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This report presents a brief introduction to wind energy and technologies available for horizontal wind turbines. A detailed taxonomy for horizontal axis wind turbines is presented covering parts of the turbine, control systems, applications among others. A detailed landscape analysis of patent and non-patent literature is done with a focus on Doubly-fed Induction Generators (DFIG) used in the horizontal axis wind turbines for efficient power generation. The product information of major players in the market is also captured for Doubly-fed Induction Generators. The final section of the report covers the existing and future market predictions for wind energy-based power generation.
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[[Image:Wind_Flowchart.PNG|right|580px|thumb|Process Flow]]
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<br>
 
=Introduction=
 
=Introduction=
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* Humans have been using wind power for at least 5000 BC to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. The use of wind to provide mechanical power came later.
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* We have been using wind power at least since 5000 BC to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. The use of wind to provide mechanical power came later.
 
* Harnessing renewable alternative energy is the ideal way to tackle the energy crisis, with due consideration given to environmental pollution, that looms large over the world.
 
* Harnessing renewable alternative energy is the ideal way to tackle the energy crisis, with due consideration given to environmental pollution, that looms large over the world.
  
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* Renewable energy is also called "clean energy" or "green power" because it doesn’t pollute the air or the water. Wind energy is one such renewable energy source that harnesses natural wind power.
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* Renewable energy is also called "clean energy" or "green power" because it doesn’t pollute the air or the water. Wind energy is one such renewable energy source that harnesses natural wind power.<br>
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== Read More? ==
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Click on '''[[Wind Energy Background]]''' to read more about wind energy.
  
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==Brief History of Wind Energy==
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In order to overcome the problems associated with fixed speed wind turbine system and to maximize the wind energy capture, many new wind farms are employing variable speed wind energy conversion systems (WECS) with doubly-fed induction generator (DFIG). It is the most popular and widely used scheme for the wind generators due to its advantages.
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Although the use of wind power started around 5000 BC, but electric power generation through wind energy started in 18th century and increasing drastically in 19th and 20th centuries. A brief view on developments on wind power sector are listed below.
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[[Image:totalcapacityworld2009.JPEG|thumb|right|400px|Fig 1 [http://www.wwindea.org/home/index.php Development of wind power worldwide]]]
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* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1887]        :  Prof. James Blyth of Scotland used windmills for generating electricity.
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* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1888]      :  Charles Brush developed the first wind-powered turbine that generated electricity in the United States based on emulated James Blyth work.
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* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1927]      :  Joe Jacobs and Marcellus Jacobs improved the wind turbine generator for use in farms.
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* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1931] : development of Darrieus wind turbine. It is a vertical axis turbine that rotates with wind from any direction.
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* 1941: Largest mega watt range wind turbine was connected to the local electrical distribution system on the mountain known as Grandpa's Knob in Castleton, Vermont, USA.
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* 1971: Denmark installed the first offshore wind farms
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* 1990s: More than 2200 MW capacity of wind turbines are installed in california.
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* 2003: the largest offshore wind farm North Hoyle  was built in  the United Kingdom.
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* 2003-2010: Research is going is on wind turbines in blades structures, generators, operation and protection, efficiency of wind turbines.
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Source:[[Media:windenergy.pdf| Wind Energy]]<br>
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The total installed wind power capacity from 2001 to 2010 is shown in fig. 1.  All wind turbines installed by the end of year 2009 worldwide are generating 340 TWh per annum.
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The country wise share of wind energy by the end of year 2009 is shown in fig. 2.
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[[Image:countryshare.JPEG|thumb|center|350px|Fig 2 [http://www.wwindea.org/home/index.php  Country share of total capacity]]]
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For variable-speed systems with limited variable-speed range, e.g. ±30% of synchronous speed, the doubly-fed induction generator(DFIG) can be an interesting solution. This is mainly due to the fact that the power electronic converter only has to handle a fraction (20-30%) of the total power as the converters are connected to the rotor and not to the stator. Therefore, the losses in the power electronic converter can be reduced, compared to a system where the converter has to handle the total power. The overall structure of wind power generation through DFIG as shown in the figure below.
  
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Source:[http://www.wwindea.org/home/index.php?option=com_content&task=view&id=266&Itemid=43 World Wind Energy Report 2009]
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=Market Research=
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==The History of Wind Energy==
  
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==Working Principle of Wind Turbine ==
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To read about '''the History of Wind Energy''', '''[http://dolcera.com/wiki/index.php?title=The_History_of_Wind_Energy click here]'''
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Wind is air in motion. It is a form of solar energy. Solar radiation heats every part of the Earth’s surface unevenly due to irregularities and rotation of earth. The flow of wind patterns are modified by the earth's terrain, bodies of water, and vegetative cover. When air moves, causing wind, it has kinetic energy. The kinetic energy of wind can be captured by a wind turbine and converted to other forms of energy such as electricity or mechanical power.
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[[Image:windprinciple.png|center|550px|thumb|Fig 3 [http://www.atlantissolar.com/wind_story.html Wind turbine principle]]]
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==Global Wind Energy Market==
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===Market Overview===
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* In the year 2010, the wind capacity reached worldwide '''196’630 Megawatt''', after '''159’050 MW''' in 2009, '''120’903 MW''' in 2008, and '''93’930 MW''' in 2007.
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[[Image:World_Installed2.PNG|center|600px|thumb|Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
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* Wind power showed a growth rate of '''23.6 %''', the lowest growth since 2004 and the second lowest growth of the past decade.
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* For the first time in more than two decades, the market for new wind turbines was smaller than in the previous year and reached an overall size of '''37’642 MW''', after 38'312 MW in 2009.
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[[Image:New.PNG|center|600px|thumb|Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
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* All wind turbines installed by the end of 2010 worldwide can generate '''430 Tera watt hours per annum''', more than the total electricity demand of the United Kingdom, the sixth largest economy of the world, and equaling 2.5 % of the global electricity consumption.
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* In the year 2010, altogether '''83 countries''', one more than in 2009, used wind energy for electricity generation. 52 countries increased their total installed capacity, after 49 in the previous year.
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* The turnover of the wind sector worldwide reached '''40 billion Euros (55 billion US$) in 2010''', after 50 billion Euros (70 billion US$) in the year 2009. The decrease is due to lower prices for wind turbines and a shift towards China.
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* China became number one in total installed capacity and the center of the international wind industry, and added '''18’928 Megawatt''' within one year, accounting for more than 50 % of the world market for new wind turbines.
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* The wind sector in 2010 employed '''670’000 persons''' worldwide.
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* Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.
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* WWEA sees a global capacity of '''600’000 Megawatt''' as possible by the year 2015 and more than '''1’500’000 Megawatt''' by the year 2020.
  
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Sources:[http://windeis.anl.gov/guide/basics/index.cfm Wind Energy Basics],[http://www1.eere.energy.gov/windandhydro/wind_how.html#inside How Wind Turbines Work]
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Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]
  
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==Horizontal Axis and Vertical Axis Wind Turbines ==
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===Global Market Forecast===
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Wind turbines are mainly classified into two types based on the axis in which turbine rotates. They are Horizontal axis wind turbine and vertical axis wind turbine.
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* Global Wind Energy Outlook 2010, provides forecast under  [http://dolcera.com/wiki/index.php?title=Forecast_Scenarios three different scenarios] - Reference, Moderate and Advanced.
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* The Global Cumulative Wind Power Capacity is estimated to reach 572,733 MW by the year 2030, under the Reference Scenario
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* The Global Cumulative Wind Power Capacity is estimated to reach 1,777,550 MW by the year 2030, under the Moderate Scenario
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* The Global Cumulative Wind Power Capacity is estimated to reach 2,341,984 MW by the year 2030, under the Advanced Scenario
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* The following chart shows the Global Cumulative Wind Power Capacity Forecast,under the different scenarios:
  
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
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[[Image:Global_Forecast.PNG|center|1080px|thumb|Global Cumulative Wind Power Capacity Forecast, Source: [http://www.gwec.net/fileadmin/documents/Publications/GWEO%202010%20final.pdf Global Wind Energy Outlook 2010]]]
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| align = "center" bgcolor = "#83caff"|'''Horizontal axis wind turbines'''
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| align = "center" bgcolor = "#83caff"|'''Vertical axis wind turbines'''
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|
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* It is mounted on top of a tower ,requires huge towers leads to complex in operation, maintanace and high intial costs.
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* It operates only with upstream or down stream wind directions.
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* It can be constructed in offshores.
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* It produces large amount of electricity with high efficiency.
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[[Image:Horizontal.jpg|center|thumb|Fig 4(a) [http://www.windturbinesnow.com/horizontalaxis-windturbines.htm Horizontal axis wind turbine]]]
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|
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* These are easy to build and maintain, safer, easier to transport and they can be mounted close to the ground.
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* These can handle much turblence in wind than horizontal wind turbines.
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* Mostly it can be constructed with two blades
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* It operates with any direction of wind
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* Production of electricity is less due to low wind speeds near to ground
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[[Image:vertical.jpg|center|thumb|Fig 4(b)[http://www.solarpowerwindenergy.org/2009/12/25/types-of-wind-turbines/ Vertical axis wind turbine]]]
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|}
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Source:[http://www.windpowertv.com/forum/index.php?topic=18.0 Different types of wind turbines]
 
  
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=Horizontal Axis Wind Turbines=
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Source: [http://www.gwec.net/fileadmin/documents/Publications/GWEO%202010%20final.pdf Global Wind Energy Outlook 2010]
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== Onshore and Offshore Wind Turbines ==
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
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| align = "center" bgcolor = "#83caff"| '''Onshore wind turbines'''
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| align = "center" bgcolor = "#83caff"| '''Offshore wind turbines'''
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===Market Growth Rates===
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| Advantages
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* The growth rate is the relation between the new installed wind power capacity and the installed capacity of the previous year.
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* With '''23.6 %''', the year 2010 showed the second lowest growth rate of the last decade.
  
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* It requires cheaper foundations
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[[Image:World_Market_Growth Rates.PNG|center|600px|thumb|World Market Growth Rates, Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
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* Easily intergrated with the electrical- grid network
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* cheaper Installation and access during the construction phase.
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* It can be operated and maintained easily and cheaply
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Source:[http://www.house-energy.com/Wind/Offshore-Onshore.htm Onshore Vs Offshore Wind Turbines]
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| These are two types, namely Near shore and Off shore.
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* Before 2010, the annual growth rate had continued to increase since the year 2004, '''peaking in 2009 at 31.7%''', the highest rate since 2001.
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* The highest growth rates of the year 2010 by country can be found in '''Romania''', which increased its capacity by 40 times.
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* The second country with a growth rate of more than 100 % was '''Bulgaria (112%)'''.
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* In the year 2009, four major wind markets had more than doubled their wind capacity: '''China, Mexico, Turkey, and Morocco'''.
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* Next to China, strong growth could be found mainly in '''Eastern European and South Eastern European''' countries: Romania, Bulgaria, Turkey, Lithuania, Poland, Hungary, Croatia and Cyprus, and Belgium.
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* Africa (with the exception of Egypt and Morocco) and Latin America (with the exception of Brazil), are again lagging behind the rest of the world in the commercial use of wind power.
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* The Top 10 countries by Growth Rate are shown in the figure listed below (only markets bigger than 200 MW have been considered):
  
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Advantages:
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[[Image:Top_Growth_Countries.PNG|center|600px|thumb|Top Countries by Market Growth Rates, Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
  
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* The roughness of the water surface is very low Wind and obstacles to the wind are less.  
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==Geographical Market Distribution==
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so, large turbines can be installed
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* China became number one in total installed capacity and the center of the international wind industry, and added '''18'928 Megawatt''' within one year, accounting for more than 50 % of the world market for new wind turbines.
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* Noise pollution is also not a factor because these are too far from shores
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* Major decrease in new installations can be observed in North America and the '''USA lost its number one position''' in total capacity to China.
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* Less affected to turbulance in wind and low wind shear<br/>
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* Many Western European countries are showing stagnation, whereas there is strong growth in a number of Eastern European countries.
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|-
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* '''Germany''' keeps its number one position in Europe with '''27'215 Megawatt''', followed by Spain with 20'676 Megawatt.
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|  Disadvantages
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* The highest shares of wind power can be found in three European countries: '''Denmark (21.0%), Portugal (18.0 %) and Spain (16.0%)'''.
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* Neagtive visual impact or noise.
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* '''Asia''' accounted for the largest share of new installations '''(54.6%)''', followed by '''Europe (27.0%)''' and '''North America (16.7 %)'''.
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* Limted avaliability of lands
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* '''Latin America (1.2%)''' and '''Africa (0.4%)''' still played only a marginal role in new installations.
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* Restrictions asscociated with obstructions like buildings, mountains, etc.
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* Africa: North Africa represents still lion share of installed capacity, wind energy plays hardly a role yet in Sub-Sahara Africa.
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* Noise pollution
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* Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.
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* Afftected to more turbulance
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Sources:[http://library.thinkquest.org/06aug/01335/wind%20Power.htm Wind Power],[http://www.ehow.com/list_5938067_types-wind-farms-there_.html Types of Wind Farms]
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| Disadvantages:
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* Installing offshore windturbines is much more complex and costly
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* Connection to the utility grid is also much more complex and expensive
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* Operation and maintanances is also a complex task with off shore wind turbines
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Source:[http://www.offshorewindenergy.org/ca-owee/indexpages/Offshore_technology.php?file=offtech_p2.php Offshore Technology]
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| align = "center"|[[Image:Onshore.jpeg|center|thumb|Fig 5(a) [http://www.eco-trees.org/europes-biggest-onshore-wind-farm-goes-online/ Onshore Wind turbines]]]
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| align = "center"|[[Image:offshore.jpeg|center|thumb|Fig5(b) [http://www.house-energy.com/Wind/Offshore-Onshore.htm Offshore wind turbines]]]
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|}
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==Parts of a Horizontal Axis Wind Turbine==
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Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]
  
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The regional breakdowns for the period 2009-2030 has been provided for the following three scenarios:
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;# [[Regional Breakdown: Reference scenario (GWEO 2010)]]
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;# [[Regional Breakdown: Moderate scenario (GWEO 2010)]]
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;# [[Regional Breakdown: Advanced scenario (GWEO 2010)]]
  
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The basic parts of a horizontal axis wind turbine(HAWT) is foundation, tower, nacelle, Generator, Rotor Blades.
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''Note: To know more about the '''Forecast Scenarios''' [http://dolcera.com/wiki/index.php?title=Forecast_Scenarios click here]''
  
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[[Image:partss.jpeg|center|300px|thumb|Fig 6 [http://www.solarpowerwindenergy.org/2010/04/02/parts-of-a-wind-turbine/ Wind turbine parts]]]
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==Country-wise Market Distribution==
  
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'''Foundation''': A very good foundation is required to support the tower and various parts of a wind turbine
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* In 2010, the Chinese wind market represented more than half of the world market for new wind turbines adding '''18.9 GW''', which equals a market share of '''50.3%'''.
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which weighs in tonnes.
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* A sharp decrease in new capacity happened in the USA whose share in new wind turbines fell down to '''14.9% (5.6 GW)''', after 25.9% or 9.9 GW in
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the year 2009.
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* '''Nine further countries''' could be seen as major markets, with turbine sales in a range '''between 0.5 and 1.5 GW''': Germany, Spain, India, United
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Kingdom, France, Italy, Canada, Sweden and the Eastern European newcomer Romania.
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* Further, '''12 markets''' for new turbines had a medium size '''between 100 and 500 MW''': Turkey, Poland, Portugal, Belgium, Brazil, Denmark, Japan, Bulgaria, Greece, Egypt, Ireland, and Mexico.
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* By end of 2010, '''20 countries''' had installations of '''more than 1 000 MW''', compared with 17 countries by end of 2009 and 11 countries byend of 2005.
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* Worldwide, '''39 countries''' had wind farms with '''a capacity of 100 Megawatt''' or more installed, compared with 35 countries one year ago, and 24 countries five years ago.
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* The top five countries (USA, China, Germany, Spain and India) represented '''74.2%''' of the worldwide wind capacity, significantly more than 72.9 % in the year.
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* The '''USA and China''' together represented '''43.2%''' of the global wind capacity (up from 38.4 % in 2009).
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* The newcomer on the list of countries using wind power commercially is a Mediterranean country, '''Cyprus''', which for the first time installed a larger grid-connected wind farm, with 82 MW.
  
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===Tower===
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Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]
  
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A tower that supports the nacelle and rotor hub at its top. These are made from tubular steel, concrete, or steel lattice. Height of the tower is an important in design of HWAT. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Generally output power of the wind system increase with increase in height and also reduces the turbulance in wind. The theoritical view of tower height versus power out is shown in figure 7 .
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The top 10 countries by Total Installed Capacity for the year 2010, is illustrated in the chart below:
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click on the link to get more about towers [[Wind Turbine Towers]]
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[[Image:Top_Installed_Countries.PNG|center|600px|thumb|Top Countries by Market Growth Rates, Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
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[[Image:height.jpeg|center|300px|thumb| Fig 7 [http://www.windsolarenergy.org/map-of-best-locations-for-wind-power.htm Tower height Vs Power output]]]
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Source:[http://windsine.org/?act=spage&f=wind The Fundamentals of Wind Energy]
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
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To view the Top 10 countries by different other parameters for the year 2010, click on the links below:
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| align = "center" bgcolor = "#83caff"|'''Different types of wind turbine towers'''
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;# [[Top 10 countries by Total New Installed Capacity]]
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| align = "center" bgcolor = "#83caff"|'''Structure'''
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;# [[Top 10 countries by Capacity per Capita (kW/cap)]]
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|-
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;# [[Top 10 countries by Capacity per Land Area (kW/sq. km)]]
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|'''Tubular Tower: '''They are constructed from rolled steel plates welded together with flanges top and bottom, being sprayed with several coats of gray weatherproof paint at the construction yard. They have doors top and bottom allowing entrance to the vertical ladders inside used to access the power cables and the yaw mechanism. There are also a set of vertical ladders on the outside of the tower accessing the nacelle for maintenance and other checks.
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;# [[Top 10 countries by Capacity per GDP (kW/ million USD)]]
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|[[Image:turbular.jpeg|200px|center|thumb|Fig 8(a) [http://americanrenewableenergycorp.com/towers Tubular tower]]]
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|-
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|  '''Lattice tower''': A Lattice tower can be constructed with perfectly shapped steel rods that are put together to form a lattice. These towers are very strong and inexpensive to manufacture and easy to transport and erect.
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|[[Image:lattices.jpeg|center|200px|thumb|Fig 8(b) [http://www.mywindpowersystem.com/2010/03/wind-power-stats-quiet-critics/ Lattice tower]]]
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|-
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| '''Guyed wind tower''': These are very strong and most economical when properly installed. But it requires more space around the tower for guy wires
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|[[Image:guyed.jpeg|center|200px|thumb|Fig 8(c) [http://itgiproducts.com/energy/windTowers.asp Guy tower]]]
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|-
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| '''Tilt up wind towers:'''These type of towers are used for consumer wind energy. These turbines have locking system, while working the turbine is locked. It can easily ulocked and lowered to ground to perform repairs.
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| [[Image:tiltup.jpeg|center|200px|thumb|Fig 8(d) [http://itgiproducts.com/energy/windTowers.asp Tiltup tower]]]
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|-
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| '''Free standing tower:'''These can be used for small wind turbines with cautions.
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| [[Image:free.jpeg |center|thumb|Fig 8(e) [http://itgiproducts.com/energy/windTowers.asp Free stand tower]]]
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|}
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Sources:[http://windertower.com/ Winder Tower],[http://www.thesolarguide.com/wind-power/wind-towers.aspx Wind Towers]
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=== Blades===
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To view the '''[[Country-wise Installed Wind Power Capacity]]''' (MW) 2002-2010 (Source: World Wind Energy Association), '''[http://dolcera.com/wiki/index.php?title=Country-wise_Installed_Wind_Power_Capacity click here]'''
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Wind turbine blades are used to extract the kinetic energy of wind and convert to mechanical energy. These blades are made up of fiber glass-reinforced polyester or wood-epoxy. Wind turbines have one or two or three or multiple blades based up on the construction. Most of the HAWT have three blades. These are connected to rotor hub. Multiple blade concept is used in earlier days for pumping water and grinding etc.
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
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==Country Profiles==
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| align = "center" bgcolor = "#99ccff"|'''Single blade HAWT'''
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===China===
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| align = "center" bgcolor = "#99ccff"|'''Two blade HAWT'''
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<br>'''Wind Energy Outlook for China - 2011 & Beyond'''
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| align = "center" bgcolor = "#99ccff"|'''Three blade HAWT'''
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<br>Despite its rapid and seemingly unhampered expansion, the
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|-
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Chinese wind power sector continues to face significant
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| It reduces the cost and weight of the turbine. These are rarely used due to tower shadow effects, needs counter weights on the other side of the blade, less stability.
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challenges, including issues surrounding grid access and
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[[Image:single.jpeg|center|200px|thumb|Fig 9(a) [http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Single blade turbine]]]
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integration, reliability of turbines and a coherent strategy for
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developing China’s offshore wind resource. These issues will
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be prominent during discussions around the twelfth Five-Year
 +
Plan, which will be passed in March 2011. According to the
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draft plan, this is expected to reflect the Chinese
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government’s continuous and reinforced commitment to
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wind power development, with national wind energy targets
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of 90 GW for 2015 and 200 GW for 2020.
  
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|  It requires more complex design due to sustain of wind shocks. It is also less stable. It saves the cost and weight of one rotor blade.
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For a detailed country profile of China please visit this [[China Wind Energy Profile Link]]
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[[Image:two.jpeg|center|300px|thumb|Fig 9(b) [http://www.trendir.com/green/?start=15 Two blade turbine]]]
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|Modern wind trubines uses three blade concept. Because this structure have hight strength to withstand heavy wind stroms. Less effect due to towe shadow. Produces high output
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[[Image:three.jpeg|center| 200px|thumb|Fig 9(c) [http://www.china-windturbine.com/wind-turbines-blades.htm Three blade turbine]]]
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|}
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Sources:[http://guidedtour.windpower.org/en/tour/design/concepts.htm Wind Turbine Blades],[http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Wind Turbine Design Styles]
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===Nacelle===
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===India===
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A housing which contains all the components which is essential to operate the turbine efficiently is called a nacelle. It is fitted at the top of a tower and includes the gear box, low- and high-speed shafts, generator, controller, and brakes. A wind speed anemometer and a wind vane are mounted on the nacelle.
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<br>'''Wind Energy Main market developments in 2010'''
 +
<br>Today the Indian market is emerging as one of the major
 +
manufacturing hubs for wind turbines in Asia. Currently,
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seventeen manufacturers have an annual production capacity
 +
of 7,500 MW. According to the WISE, the annual wind turbine
 +
manufacturing capacity in India is likely to exceed
 +
17,000 MW by 2013.
 +
<br>The Indian market is expanding with the leading wind
 +
companies like Suzlon, Vestas, Enercon, RRB Energy and GE
 +
now being joined by new entrants like Gamesa, Siemens, and
 +
WinWinD, all vying for a greater market share. Suzlon, however,
 +
is still the market leader with a market share of over 50%.
 +
<br>The Indian wind industry has not been significantly affected
 +
by the financial and economic crises. Even in the face of a
 +
global slowdown, the Indian annual wind power market has
 +
grown by almost 68%. However, it needs to be pointed out
 +
that the strong growth in 2010 might have been stimulated
 +
by developers taking advantage of the accelerated
 +
depreciation before this option is phased out.
  
−
[[Image:nacell.png |center|400px|thumb|Fig 10 [http://windturbinesforthehome.com/ Internal nacelle structure]]]
+
For a detailed country profile of India please visit this [[India Wind Energy Profile Link]]
  
−
'''Hub'''
+
==Market Share Analysis==
−
A rotor hub is provided for coupling a wind turbine rotor blade and a shaft. The hub assembly consists of hub, bolts, blade bearings, pitch system and internals
+
===Global Market Share===
−
. Rotor hubs are made with welded sheet steel, cast iron, fored steel. The types of rotor hubs are
+
* Vestas leads the Global Market in the 2010 with a 12% market share according to Make Consulting, while BTM Consulting reports it to have a 14.8% market share.
−
* Hingeless hub
+
* According to Make Consulting, the global market share of Vestas has decreased from 19% in 2008, to 14.5% in 2009, to 12% in 2010.
−
* Teetering hub
+
* According to BTM Consulting, the global market share of Vestas has changed from 19% in 2008, to 12% in 2009, to 14.8% in 2010.
 +
* According to Make Consulting, the global market share of GE Energy has decreased from 18% in 2008, to 12.5% in 2009, to 10% in 2010.
 +
* The market share of world no. 2 Sinovel, has been constantly increasing, from 5% in 2008 , to 9.3% in 2009, to 11% in 2010
 +
* The top 5 companies have been occupying more than half of the Global Market Share from 2008 to 2010
  
−
[[Image:rotorhub.jpg |center|thumb|Fig 11 [http://syigroup.en.made-in-china.com/product/dbTQyzJOHYRi/China-Iron-Casting-Wind-Mill-Tower-Rotor-Hub.html Rotor hub]]]
+
Source: [http://www.make-consulting.com Make Consulting], [http://www.btmgcs.com/ BTM Global Consulting]
  
 +
The chart given below illustrates the Global Market Share Comparison of Major Wind Energy Companies for the period 2008-2010, as provided by two different agencies, Make Consulting and BTM Consulting:
 +
[[Image:Market_Share_Comparison.JPG|center|1080px|thumb|Global Market Share Comparison of Major Companies for the period 2008-2010
 +
, Source: [http://www.make-consulting.com Make Consulting], [http://www.btmgcs.com/ BTM Global Consulting]]]
  
−
'''Drive shaft'''
+
===Market Share - Top 10 Markets===
−
Drive shafts are a hollow or solid steel hardened shaft under very high stresses and considerable torque. Drive shafts are used to transfer rotational mechanical energy from blade hub to the generator to produce electricity. A wind turbine normally consists two shafts .
+
* While Vestas is the Global Leader, it is the leader in only one of Top 10 markets, which is 10<sup>th</sup> placed Sweden
−
 
+
* But, Vestas is ranked 2<sup>nd</sup> in 5 of Top 10 markets
−
'''''Main shaft''''': It is connected between blade hub and input to the gear box.  It rotates at low speeds. So It is also called as 'low speed shaft'.
+
* Sinovel, ranked 2<sup>nd</sup> globally, features only once in the Top 3 Companies list in the Top 10 markets, but scores globally because it leads the largest market China
−
 
+
* The table given below illustrates the Top 3 players in Top 10 Wind Energy Markets of the world:
−
'''''Generator shaft''''': It connects the gear box output to the generator input. It rotates at very high speed equals to the rating of the generator. It is also called 'high speed shaft'.
+
{|border="2" cellspacing="0" cellpadding="4" width="50%" align="center"
−
 
+
|bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Market'''</font>
−
[[Image:mainshaft.jpg|center|200px||thumb|Fig 12 [http://jiangyinzkforging.en.made-in-china.com/product/hewxIQjbgTpr/China-Wind-Turbine-Shaft-For-Wind-Power-Generator-ALIM2143-.html Shaft system]]]
+
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''MW'''</font>
−
 
+
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 1'''</font>
−
'''Gear box'''
+
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 2'''</font>
−
Gear box used in wind energy systems to change low speed  high toque power coming from a rotor blade to high speed low torque power which is used for generator. It is connected in between main shaft and generator shaft to increase rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1000 to 1800 rpm.
+
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 3'''</font>
−
Gearboxes used for wind turbine  are made from superior quality aluminum alloys, stainless steel, cast iron etc.
+
−
 
+
−
The various gear boxes used in wind turbines are
+
−
# Planetary Gearbox
+
−
# Helical Gearbox
+
−
# Worm Gearbox
+
−
 
+
−
[[Image:Gearra.jpg |center|250px|thumb|Fig13 [http://machinedesign.com/article/green-technology-inside-an-advanced-wind-turbine-0605 Gear box]]]
+
−
 
+
−
'''Generator'''
+
−
 
+
−
The output rotational mechanical energy of the gear box is connected to the generator through generator shaft. It works on the principle of 'Faraday's law of electromagnetic induction". It converts mechanical energy into electrical energy.
+
−
 
+
−
Sources:[http://windturbinesforthehome.com/ Wind Power Turbines], [http://www.awewind.com/Products/TurbineConstruction/MainAssembly/RotorHub/tabid/81/Default.aspx Rotor Hub Assembly],[http://www.gears-gearbox.com/wind-turbines.html Gearbox for Wind Turbines], [http://www.top-alternative-energy-sources.com/inside-a-wind-turbine.html A Wind Turbine],[http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
+
−
 
+
−
===Anemometers===
+
−
Wind speed is the most important factor for determing the power content in the wind. The power content in the wind is directly proportional to cube of the wind velocity. Measuring wind speed is important for site selection. The device which is used for measuring wind speed is called anemometer. These are usally located on top of the nacelle.
+
−
 
+
−
[[Image:windvane.png|center|300px|thumb|Fig 14 [http://www1.eere.energy.gov/windandhydro/wind_how.html Anemometer & Wind vane]]]
+
−
Source:[http://blog.mapawatt.com/2009/07/06/make-sure-you-have-wind-speed/ Anemometer]
+
−
 
+
−
'''Types of anemometers'''
+
−
The various types of anemometers are used in measuring wind speed is shown in flow  chart below.
+
−
 
+
−
[[Image:anemometers.png|center|600px]]
+
−
 
+
−
Source:[[Media:wind_power_energy.pdf| Wind Power Energy]]
+
−
 
+
−
'''Wind vane'''
+
−
Wind vanes are used to measure the wind directions and communicates with the yaw system to orient the turbine properly with respective to wind directions, to extract maximum amount of power from wind. Wind turbines are oriented to upstream wind or down stream wind.
+
−
 
+
−
Source:[http://www.top-alternative-energy-sources.com/inside-a-wind-turbine.html A Wind Turbine]
+
−
 
+
−
===Yaw Mechanism===
+
−
yaw mechanism turns the rotor into the upwind direction as the wind direction changes. Electric motors and gear boxes are used to keep the turbine yawed against wind. This can be also used as controlling mechanism during high wind speeds.
+
−
[[Image:yawsystem.png|center|350px|thumb|Fig 15 Yaw structure]]
+
−
Source:[http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
+
−
 
+
−
=Electrical Generating Systems=
+
−
 
+
−
The various types of electrical generators are used in wind energy systems are shown in figure.
+
−
[[Image:generator.png|center|600px]]
+
−
 
+
−
Source:[[Media:windturbinegenerators.pdf|Wind Turbine Generators]]
+
−
 
+
−
The most commonly used generator systems applied in wind turbines are are explained below.
+
−
 
+
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
−
| align = "center" bgcolor = "#83caff"|
+
−
| align = "center" bgcolor = "#83caff"|'''Fixed speed generating systems'''
+
−
| align = "center" bgcolor = "#83caff"|'''Variable speed generating systems'''
+
−
| align = "center" bgcolor = "#83caff"|'''Doubly fed induction generator'''
+
−
 
+
 
|-
 
|-
−
| Structure
+
|bgcolor = "#DBE5F1"|'''China'''
−
| [[Image:fixed.png|center|250px]]
+
|align = "center" bgcolor = "#DBE5F1"|18928
−
| [[Image:variable.png|center|250px]]
+
|align = "center" bgcolor = "#DBE5F1"|Sinovel
−
| [[Image:dfigg.png|center|250px]]
+
|align = "center" bgcolor = "#DBE5F1"|Goldwind
−
 
+
|align = "center" bgcolor = "#DBE5F1"|Dongfang
 
|-
 
|-
−
| Machines
+
|bgcolor = "#DBE5F1"|'''USA'''
−
| SQIG
+
|align = "center" bgcolor = "#DBE5F1"|5115
−
| PMSG/WRSG/WRIG
+
|align = "center" bgcolor = "#DBE5F1"|GE Energy
−
| DFIG
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
−
 
+
|align = "center" bgcolor = "#DBE5F1"|Siemens
 
|-
 
|-
−
| Advantages
+
|bgcolor = "#DBE5F1"|'''India'''
−
| <nowiki>* Simple and low cost </nowiki>
+
|align = "center" bgcolor = "#DBE5F1"|2139
−
<nowiki>* Low maintanace  </nowiki>
+
|align = "center" bgcolor = "#DBE5F1"|Suzlon
−
| <nowiki>* Complete control of real and reactive powers</nowiki>
+
|align = "center" bgcolor = "#DBE5F1"|Enercon
−
 
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
−
<nowiki>* High energy efficiency </nowiki>
+
−
| <nowiki>* Reduced capacity converter</nowiki>
+
−
 
+
−
<nowiki>* Decoupled control of active and reactive power flow</nowiki>
+
−
 
+
−
<nowiki>* Smooth grid connection</nowiki>
+
−
 
+
 
|-
 
|-
−
| Drawbacks
+
|bgcolor = "#DBE5F1"|'''Germany'''
−
|  <nowiki>* </nowiki>No control on real and reactive power
+
|align = "center" bgcolor = "#DBE5F1"|1551
−
 
+
|align = "center" bgcolor = "#DBE5F1"|Enercon
−
<nowiki>* Less optimum power extraction capability</nowiki>
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
−
 
+
|align = "center" bgcolor = "#DBE5F1"|Suzlon
−
<nowiki>* Poor power factor</nowiki>
+
−
 
+
−
<nowiki>* High mechanical stress on turbine mechanical components</nowiki>
+
−
|  <nowiki>* Additional cost of power electronics</nowiki>
+
−
 
+
−
<nowiki>* Limited fault ride through capability</nowiki>
+
−
| <nowiki>* Regular maintenance of slip ring and gearbox</nowiki>
+
−
 
+
−
<nowiki>* Limited fault ride-through capability</nowiki>
+
−
 
+
−
|}
+
−
Source:[http://www.uni-hildesheim.de/~irwin/inside_wind_turbines.html Inside wind turbines]
+
−
 
+
−
=Wind Turbine Control Systems=
+
−
As the wind turbines increases in size and power, control systems plays a major role to operate wind turbines in safe region and also to improve efficiency and quality of power conversion. The main objectives of wind turbine control systems is
+
−
*''Energy capture'' : Operating the wind turbine to extract maximum amount of energy considering safe restrictions like rated power, rated speed, cut-out wind speed etc.,
+
−
* ''Mechanical loads'': protecting the systems from transient loads.
+
−
* ''Power quality'': Conditioning the generated power with grid interconnection standards.
+
−
The various control techniques used in wind turbines are shown in table below
+
−
 
+
−
 
+
−
 
+
−
 
+
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
−
|align = "center" bgcolor = "#83caff"|'''Control System'''
+
−
|align = "center" bgcolor = "#83caff"|'''Pitch contol'''
+
−
|align = "center" bgcolor = "#83caff"|'''Yaw control'''
+
−
|align = "center" bgcolor = "#83caff"|'''Stall control'''
+
−
|align = "center" bgcolor = "#83caff"|'''Generator torque control'''
+
 
|-
 
|-
−
|align = "center" bgcolor = "#83caff"|'''Description'''
+
|bgcolor = "#DBE5F1"|'''UK'''
−
| A method of controlling the speed of a wind turbine by varying the orientation, or pitch, of the blades, and thereby altering its aerodynamics and efficiency.
+
|align = "center" bgcolor = "#DBE5F1"|1522
−
[[Image:pitch.jpg|thumb|center|175px|Fig 16(a) [http://zone.ni.com/devzone/cda/tut/p/id/8189 Pitch control]]]
+
|align = "center" bgcolor = "#DBE5F1"|Siemens
−
Source:[http://www.moog.com/markets/energy/wind-turbines/blade-pitch-control/ Blade Pitch Control]
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
−
| The rotation of horizontal axis wind turbine around its tower to orient the turbine in upwind or down wind direction.
+
|align = "center" bgcolor = "#DBE5F1"|Gamesa
−
[[Image:Yaw.jpg|thumb|center|175px||Fig 16(b) [http://zone.ni.com/devzone/cda/tut/p/id/8189 Yaw control]]]
+
−
Source:[http://zone.ni.com/devzone/cda/tut/p/id/8189 Wind Turbine Control Methods]
+
−
|Stall control works by increasing the angle at which the relative wind strikes the blades (angle of attack). As the wind speed increases drag force on the blade increase and lift force gets reduces, thus finally reduces the speed of turbine.A fully stalled turbine blade, when stopped, has the flat side of the blade facing directly into the wind. Compare with furling.
+
−
Source:[http://www.windmeup.org/2008/03/stall-control-basics.html Stall-control basics]
+
−
|As the aerodynamic torque control changes, rotor speed changes. it changes the output power frequency. A frequency converter is connected in between generator and the network to maintain generator power constant.
+
−
Source[[Media:windenergycontrol.pdf|Wind Energy Control]]
+
 
|-
 
|-
−
|}
+
|bgcolor = "#DBE5F1"|'''Spain'''
−
 
+
|align = "center" bgcolor = "#DBE5F1"|1516
−
=Taxonomy for Wind Turbines=
+
|align = "center" bgcolor = "#DBE5F1"|Gamesa
−
[[Image:windTurbines12.jpeg|center|1000px]]
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
−
 
+
|align = "center" bgcolor = "#DBE5F1"|GE Energy
−
==Major IPC classes==
+
−
A majority of patents describing wind turbines or wind energy are classified in the following IPC classifications.
+
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
−
| align = "center" bgcolor = "#99ccff"|'''S.NO'''
+
−
| align = "center" bgcolor = "#99ccff"|'''IPC Classification'''
+
−
| align = "center" bgcolor = "#99ccff"|'''Description'''
+
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|1
+
|bgcolor = "#DBE5F1"|'''France'''
−
| align = "center"|F03D
+
|align = "center" bgcolor = "#DBE5F1"|1186
−
| WIND MOTORS
+
|align = "center" bgcolor = "#DBE5F1"|Enercon
 +
|align = "center" bgcolor = "#DBE5F1"|Suzlon
 +
|align = "center" bgcolor = "#DBE5F1"|Vestas
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|2
+
|bgcolor = "#DBE5F1"|'''Italy'''
−
| align = "center"|F16C
+
|align = "center" bgcolor = "#DBE5F1"|948
−
| SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OF CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
+
|align = "center" bgcolor = "#DBE5F1"|Gamesa
 +
|align = "center" bgcolor = "#DBE5F1"|Vestas
 +
|align = "center" bgcolor = "#DBE5F1"|Suzlon
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|3
+
|bgcolor = "#DBE5F1"|'''Canada'''
−
| align = "center"|F16H
+
|align = "center" bgcolor = "#DBE5F1"|690
−
| GEARING
+
|align = "center" bgcolor = "#DBE5F1"|Siemens
 +
|align = "center" bgcolor = "#DBE5F1"|GE Energy
 +
|align = "center" bgcolor = "#DBE5F1"|Enercon
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|4
+
|bgcolor = "#DBE5F1"|'''Sweeden'''
−
| align = "center"|F03B
+
|align = "center" bgcolor = "#DBE5F1"|604
−
| MACHINES OR ENGINES FOR LIQUIDS
+
|align = "center" bgcolor = "#DBE5F1"|Vestas
 +
|align = "center" bgcolor = "#DBE5F1"|Enercon
 +
|align = "center" bgcolor = "#DBE5F1"|Siemens
 
|-
 
|-
−
|align = "center" bgcolor = "#99ccff"|5
+
|align = "center" bgcolor = "#DBE5F1" colspan = "5"|''Source: BTM Consult - part of Navigant Consulting - March 2011''
−
|align = "center"|H02K
+
−
|DYNAMO-ELECTRIC MACHINES
+
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|6
+
|}<br clear="all">
−
| align = "center"|H02P
+
 
−
| CONTROL OR REGULATION OF ELECTRIC MOTORS, GENERATORS, OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
+
Source: [http://www.btm.dk/reports/world+market+update+2010 BTM Consult]
 +
 
 +
==Company Profiles==
 +
 
 +
# '''[[Vestas Wind Systems A/S]]'''
 +
# '''[[Suzlon Energy]]'''
 +
 
 +
==Major Wind Turbine Suppliers==
 +
{|border="2" cellspacing="0" cellpadding="4" width="50%" align="center"
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Turbine maker'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Rotor blades'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Gear boxes'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Generators'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Towers'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Controllers'''</font>
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|7
+
|bgcolor = "#DBE5F1"|Vestas
−
| align = "center"|H02M
+
|bgcolor = "#DBE5F1"|Vestas, LM
−
| APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION
+
|bgcolor = "#DBE5F1"|Bosch Rexroth, Hansen, Wingery, Moventas
 +
|bgcolor = "#DBE5F1"| Weier, Elin, ABB, LeroySomer
 +
|bgcolor = "#DBE5F1"| Vestas, NEG, DMI
 +
|bgcolor = "#DBE5F1"|Cotas (Vestas),<br>NEG (Dancontrol)
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|8
+
|bgcolor = "#DBE5F1"|GE energy
−
| align = "center"|H02J
+
|bgcolor = "#DBE5F1"|LM, Tecsis
−
| CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
+
|bgcolor = "#DBE5F1"|Wingery, Bosch, Rexroth, Eickhoff, GE
 +
|bgcolor = "#DBE5F1"|Loher, GE
 +
|bgcolor = "#DBE5F1"|DMI, Omnical, SIAG
 +
|bgcolor = "#DBE5F1"|GE
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|9
+
|bgcolor = "#DBE5F1"|Gamesa
−
| align = "center"|G06F
+
|bgcolor = "#DBE5F1"|Gamesa, LM
−
| ELECTRIC DIGITAL DATA PROCESSING
+
|bgcolor = "#DBE5F1"| Echesa (Gamesa), Winergy, Hansen
 +
|bgcolor = "#DBE5F1"|Indar (Gamesa), Cantarey
 +
|bgcolor = "#DBE5F1"|Gamesa
 +
|bgcolor = "#DBE5F1"| Ingelectric (Gamesa)
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|10
+
|bgcolor = "#DBE5F1"|Enercon
−
| align = "center"|G05F
+
|bgcolor = "#DBE5F1"|Enercon
−
| SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
+
|bgcolor = "#DBE5F1"|Direct drive
 +
|bgcolor = "#DBE5F1"|Enercon
 +
|bgcolor = "#DBE5F1"|KGW, SAM
 +
|bgcolor = "#DBE5F1"|Enercon
 
|-
 
|-
−
| align = "center" bgcolor = "#99ccff"|11
+
|bgcolor = "#DBE5F1"| Siemens<br>wind
−
| align = "center"|H02H
+
|bgcolor = "#DBE5F1"|Siemens, LM
−
| EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
+
|bgcolor = "#DBE5F1"|Winergy
−
|}
+
|bgcolor = "#DBE5F1"|ABB
−
 
+
|bgcolor = "#DBE5F1"|Roug, KGW
−
== Major Players==
+
|bgcolor = "#DBE5F1"| Siemens, KK Electronic
−
Major players in the Wind Energy sector include: General Electric, Vestas Wind Systems, Siemens AG, Mitsubishi Ltd, REPower Systems AG, Gamesa Innovation & Technology, Enercon, Nordex, Suzlon and Sinovel Wind Group Co. Ltd.
+
−
 
+
−
=<span style="color:#C41E3A">Like this report?</span>=
+
−
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+
−
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−
|style="background:lightgrey" align = "center"  colspan = "3"|'''[mailto:info@dolcera.com <span style="color:#0047AB">Buy the customized report from Dolcera</span>]'''
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|-
 
|-
−
| align = "center"| [http://www.dolcera.com/website_prod/services/ip-patent-analytics-services Patent Analytics Services]
+
|bgcolor = "#DBE5F1"|Suzlon
−
|align = "center"| [http://www.dolcera.com/website_prod/services/business-research-services Market Research Services]
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|bgcolor = "#DBE5F1"|Suzlon
−
|align = "center"| [http://www.dolcera.com/website_prod/tools/patent-dashboard Purchase Patent Dashboard]
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|bgcolor = "#DBE5F1"|Hansen, Winergy
 +
|bgcolor = "#DBE5F1"| Suzlon,<br>Siemens
 +
|bgcolor = "#DBE5F1"|Suzlon
 +
|bgcolor = "#DBE5F1"| Suzlon, Mita Teknik
 
|-
 
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−
|align = "center"| [http://www.dolcera.com/website_prod/services/ip-patent-analytics-services/patent-search/patent-landscapes Patent Landscape Services]
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|bgcolor = "#DBE5F1"|Repower
−
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|bgcolor = "#DBE5F1"|LM
−
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+
|bgcolor = "#DBE5F1"| Winergy, Renk, Eickhoff
 +
|bgcolor = "#DBE5F1"|N/A
 +
|bgcolor = "#DBE5F1"|N/A
 +
|bgcolor = "#DBE5F1"| Mita Teknik, ReGuard
 
|-
 
|-
−
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+
|bgcolor = "#DBE5F1"|Nordex
−
|align = "center"| [http://www.dolcera.com/website_prod/services/ip-patent-analytics-services/alerts-and-updates Patent Alerting Services]
+
|bgcolor = "#DBE5F1"|Nordex
−
|align = "center"| [http://www.dolcera.com/website_prod/tools Dolcera Tools]
+
|bgcolor = "#DBE5F1"| Winergy, Eickhoff, Maag
 +
|bgcolor = "#DBE5F1"|Loher
 +
|bgcolor = "#DBE5F1"| Nordex, Omnical
 +
|bgcolor = "#DBE5F1"| Nordex, Mita Teknik
 
|-
 
|-
−
|}
+
|align = "center" bgcolor = "#DBE5F1" colspan = "6"|''Source: BTM Consult''
−
<br>
+
−
 
+
−
= Doubly-fed Induction Generator=
+
−
The present study on the IP activity in the area of horizontal axis wind turbines with focus on '''''Doubly-fed Induction Generator (DFIG)''''' is based on a search conducted on Thomson Innovation.
+
−
==Control patents==
+
−
 
+
−
{|border="2" cellspacing="0" cellpadding="5" width="100%"
+
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''S No'''</center>
+
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''Patent / Publication No.'''</center>
+
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''Publication Date'''</center>
+
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''Assignee / Applicant'''</center>
+
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''Title'''</center>
+
−
 
+
 
|-
 
|-
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''1'''</center>
+
|}<br clear="all">
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6278211.PN.&OS=PN/6278211&RS=PN/6278211 US6278211B1]</center>
+
−
|  <center>02/08/01</center>
+
−
|  <center>SWEO EDWIN A</center>
+
−
|  Brushless doubly-fed induction machines employing dual cage rotors
+
  
 +
==Products of Top Companies==
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width=”42”|<font color="#FFFFFF">'''S.No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Company'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Product'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Specifications'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 +
|bgcolor = "#DCE6F1"|V80
 +
|bgcolor = "#DCE6F1"|'''Rated Power: '''2.0 MW,  '''Frequency:''' 50 Hz/60 Hz, '''Number of Poles:''' 4-pole, '''Operating Temperature: -'''30°C to 40°
 +
|- valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 +
|V90
 +
|'''Rated Power:''' 1.8/2.0 MW, '''Frequency :''' 50 Hz/60 Hz, '''Number of Poles :''' 4-pole(50 Hz)/6-pole(60 Hz), '''Operating Temperature: -'''30°C to 40°
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 +
|bgcolor = "#DCE6F1"|V90 Offshore
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 3.0 MW, '''Frequency:''' 50 Hz/60 Hz, '''Number of Poles:''' 4-pole, '''Operating Temperature: '''-30°C to 40°
 +
|- valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://www.china-windturbine.com/news/doubly_wind_turbines.htm North Heavy Company]</u></font>
 +
|2 MW DFIG
 +
|'''Rated Power:''' 2.0 MW, '''Rated Voltage:''' 690V, '''Rated Current:''' 1670A, '''Frequency:''' 50Hz, '''Number of Poles :''' 4-pole,  '''Rotor Rated Voltage:''' 1840V, '''Rotor Rated Current''' 670A, '''Rated Speed:''' 1660rpm;''' Power Speed Range: '''520-1950 rpm, '''Insulation Class:''' H, '''Protection Class:''' IP54,  '''Motor Temperature Rise''' =<nowiki><</nowiki>95K
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://docs.google.com/viewer?a=v&q=cache:X9KReq0YEigJ:www.iberdrolarenewables.us/bluecreek/docs/primary/03-Appendices/_Q-Brochure-of-G-90-Turbine/Brochure-G-90-Turbine.pdf+gamesa+g90&hl=en&pid=bl&srcid=ADGEESgldaLogi1i5Pg71zE-FO_AMqbeKL5wJiA8LVklgq5ev2in Gamesa]</u></font>
 +
|bgcolor = "#DCE6F1"|G90
 +
|bgcolor = "#DCE6F1"|'''Rated Voltage:''' 690 V,  '''Frequency:''' 50 Hz,  '''Number of Poles:''' 4,  '''Rotational Speed:''' 900:1,900 rpm (rated 1,680 rpm) (50Hz); '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class:''' IP 54, '''Power Factor(standard):'''  0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power Factor(Optional):''' 0.95 CAP - 0.95 IND throughout the power range
 +
|- valign="top"
 +
|align = "center"|6
 +
|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 +
| N80
 +
|'''Rated Power:''' 2.5 MW, '''Rated Voltage:''' 690V, '''Frequency:''' 50/60Hz, '''Cooling Systems:''' liquid/air
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 +
|bgcolor = "#DCE6F1"| N90
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 2.5 MW, '''Rated Voltage: '''690V,''' Frequency: '''50/60Hz,''' Cooling Systems: '''liquid/air
 +
|- valign="top"
 +
|align = "center"|8
 +
|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 +
|N100
 +
|'''Rated Power:''' 2.4 MW, '''Rated Voltage: '''690V, '''Frequency: '''50/60Hz, '''Cooling Systems: '''liquid/air
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 +
|bgcolor = "#DCE6F1"| N117
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 2.5 MW, '''Rated Voltage: '''690V, '''Frequency: '''50/60Hz, '''Cooling Systems: '''liquid/air
 +
|- valign="top"
 +
|align = "center"|10
 +
|<font color="#0000FF"><u>[http://www.converteam.com/majic/pageServer/1704040148/en/index.html Converteam]</u></font>
 +
|DFIG
 +
|NA
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|11
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://geoho.en.alibaba.com/product/252321923-0/1_5MW_doubly_fed_asynchronous_generator.html Xian Geoho Energy Technology]</u></font>
 +
|bgcolor = "#DCE6F1"|1.5MW DFIG
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1550KW,  '''Rated Voltage: '''690V, '''Rated Speed: '''1755 r/min, '''Speed Range: '''975<nowiki>~</nowiki>1970 r/min, '''Number of Poles: '''4-pole, '''Stator Rated Voltage: '''690V±10%, '''Stator Rated Current: '''1115A; '''Rotor Rated Voltage: '''320V, '''Rotor Rated Current: '''430A, '''Winding Connection: '''Y / Y, '''Power Factor: '''0.95(Lead) <nowiki>~</nowiki> 0.95Lag,''' Protection Class: '''IP54, '''Insulation Class: '''H, '''Work Mode: '''S1, '''Installation ModeI: '''M B3, '''Cooling Mode: '''Air cooling,  '''Weight: '''6950kg
 +
|- valign="top"
 +
|align = "center"|12
 +
|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 +
|TW450XX (0.5-1 KW)
 +
|'''Rated Power:''' 0.5 -1 KW, '''Rated Voltage: '''460/ 575/ 690 V, '''Frequency: '''50/ 60 Hz, '''Number of Poles: '''4/6,''' Ambient Temp.(°C): -'''40 to 50, '''Speed Range (% of Synch. Speed): '''68% to 134%,  '''Power Factor (Leading): -'''0.90 to <nowiki>+</nowiki>0.90 , '''Insulation Class: '''H/F, '''Efficiency: '''<nowiki>></nowiki>= 96%
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|13
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 +
|bgcolor = "#DCE6F1"|TW500XX (1-2 KW)
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1-2 kW,''' Rated Voltage:''' 460/ 575/ 690 V, '''Frequency:''' 50/ 60 Hz, '''Number of Poles:''' 4/6, Ambient Temp.(°C): -40 to 50; '''Speed Range (% of Synch. Speed):''' 68 to 134%, '''Power Factor(Leading): -'''0.90 to <nowiki>+</nowiki>0.90, '''Insulation Class: '''H/F, '''Efficiency:''' <nowiki>></nowiki>= 96%
 +
|- valign="top"
 +
|align = "center"|14
 +
|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 +
|TW560XX (2-3 KW)
 +
|'''Rated Power: '''2-3kW, '''Rated Voltage: '''460/ 575/ 690 V, '''Frequency: '''50/ 60 Hz, '''Number of Poles: '''4/6, '''Ambient Temp(°C): ''' -40 to 50, '''Speed Range(% of Synch. Speed)''':''' '''68 to 134%, '''Power Factor(Leading):''' -0.90 to <nowiki>+</nowiki>0.90, '''Insulation Class: '''H/F, '''Efficiency:''' <nowiki>></nowiki>= 96%.
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|15
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.acciona-na.com/About-Us/Our-Projects/U-S-/West-Branch-Wind-Turbine-Generator-Assembly-Plant.aspx Acciona]</u></font>
 +
|bgcolor = "#DCE6F1"|AW1500
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1.5MW, '''Rated Voltage: '''690 V, '''Frequency: '''50 Hz, '''Number of Poles: '''4,  '''Rotational Speed: '''900:1,900 rpm(rated 1,680 rpm) (50Hz), '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class: '''IP54, '''Power Factor(standard): '''0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power factor(optional):''' 0.95 CAP - 0.95 IND throughout the power range
 +
|- valign="top"
 +
|align = "center"|16
 +
|<font color="#0000FF"><u>[http://www.acciona-na.com/About-Us/Our-Projects/U-S-/West-Branch-Wind-Turbine-Generator-Assembly-Plant.aspx Acciona]</u></font>
 +
|AW3000
 +
|'''Rated Power:''' 3.0MW, '''Rated Voltage: ''' 690 V, '''Frequency: '''50 Hz, '''Number of Poles: '''4, '''Rotational Speed: '''900:1,900 rpm(rated 1,680 rpm) (50Hz), '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class: '''IP54, '''Power Factor(standard): '''0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power Factor (optional):''' 0.95 CAP - 0.95 IND throughout the power range
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|17
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://gepower.com/businesses/ge_wind_energy/en/index.htm General Electric]</u></font>
 +
|bgcolor = "#DCE6F1"|GE 1.5/2.5MW
 +
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1.5/2.5 MW, '''Frequency(Hz): '''50/60
 
|-
 
|-
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''2'''</center>
+
|}
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6954004.PN.&OS=PN/6954004&RS=PN/6954004 US6954004B2]</center>
+
−
|  <center>11/10/05</center>
+
−
|  <center>SPELLMAN HIGH VOLTAGE ELECTRON</center>
+
−
|  Doubly fed induction machine
+
  
−
|-
+
= IP Search & Analysis =
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''3'''</center>
+
== Doubly-fed Induction Generator: Search Strategy ==
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7411309.PN.&OS=PN/7411309&RS=PN/7411309 US7411309B2]</center>
+
The present study on the IP activity in the area of horizontal axis wind turbines with focus on '''''Doubly-fed Induction Generator (DFIG)''''' is based on a search conducted on Thomson Innovation.
−
|  <center>12/08/08</center>
+
===Control Patents===
−
|  <center>XANTREX TECHNOLOGY INC</center>
+
−
|  Control system for doubly fed induction generator
+
  
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Patent/Publication No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD" width="15%"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6278211.PN.&OS=PN/6278211&RS=PN/6278211 US6278211]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|08/02/01
 +
|bgcolor = "#DCE6F1"|Sweo Edwin
 +
|bgcolor = "#DCE6F1"|Brush-less doubly-fed induction machines employing dual cage rotors
 +
|- valign="top"
 +
|align = "center"|2
 +
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6954004.PN.&OS=PN/6954004&RS=PN/6954004 US6954004]</u></font>
 +
|align = "center"|10/11/05
 +
|Spellman High Voltage Electron
 +
|Doubly fed induction machine
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7411309.PN.&OS=PN/7411309&RS=PN/7411309 US7411309]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|08/12/08
 +
|bgcolor = "#DCE6F1"|Xantrex Technology
 +
|bgcolor = "#DCE6F1"|Control system for doubly fed induction generator
 +
|- valign="top"
 +
|align = "center"|4
 +
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7485980.PN.&OS=PN/7485980&RS=PN/7485980 US7485980]</u></font>
 +
|align = "center"|02/03/09
 +
|Hitachi
 +
|Power converter for doubly-fed power generator system
 +
|- valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7800243.PN.&OS=PN/7800243&RS=PN/7800243 US7800243]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|09/21/10
 +
|bgcolor = "#DCE6F1"|Vestas Wind Systems
 +
|bgcolor = "#DCE6F1"|Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
 +
|- valign="top"
 +
|align = "center"|6
 +
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7830127.PN.&OS=PN/7830127&RS=PN/7830127 US7830127]</u></font>
 +
|align = "center"|11/09/10
 +
|Wind to Power System
 +
|Doubly-controlled asynchronous generator
 
|-
 
|-
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''4'''</center>
+
|}
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7485980.PN.&OS=PN/7485980&RS=PN/7485980 US7485980B2]</center>
+
−
|  <center>03/02/09</center>
+
−
|  <center>HITACHI LTD</center>
+
−
|  Power converter for doubly-fed power generator system
+
  
−
|-
+
===Patent Classes===
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''5'''</center>
+
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7800243.PN.&OS=PN/7800243&RS=PN/7800243 US7800243B2]</center>
+
−
|  <center>21/09/10</center>
+
−
|  <center>VESTAS WIND SYS AS</center>
+
−
|  Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
+
  
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Class No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Class Type'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Definition'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F03D0009000000 F03D9/00 ]</u></font>
 +
|bgcolor = "#DCE6F1"|IPC
 +
|bgcolor = "#DCE6F1"|Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / '''Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus) '''
 +
|-valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://v3.espacenet.com/eclasrch?classification=ecla&locale=en_EP&ECLA=f03d9/00c F03D9/00C ]</u></font>
 +
|ECLA
 +
|Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus) /''' The apparatus being an electrical generator '''
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#&refresh=page&notion=scheme&version=20110101&symbol=H02J0003380000 H02J3/38 ]</u></font>
 +
|bgcolor = "#DCE6F1"|IPC
 +
|bgcolor = "#DCE6F1"|Generation, conversion, or distribution of electric power / Circuit arrangements or systems for supplying or distributing electric power; systems for storing electric energy / Circuit arrangements for ac mains or ac distribution networks / '''Arrangements for parallely feeding a single network by two or more generators, converters or transformers '''
 +
|-valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02K0017420000 H02K17/42 ]
 +
</u></font>
 +
|IPC
 +
|Generation, conversion, or distribution of electric power / Dynamo-electric machines / Asynchronous induction motors; Asynchronous induction generators / '''Asynchronous induction generators '''
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02P0009000000 H02P9/00 ]</u></font>
 +
|bgcolor = "#DCE6F1"|IPC
 +
|bgcolor = "#DCE6F1"|Generation, conversion, or distribution of electric power / Control or regulation of electric motors, generators, or dynamo-electric converters; controlling transformers, reactors or choke coils /''' Arrangements for controlling electric generators for the purpose of obtaining a desired output '''
 +
|-valign="top"
 +
|align = "center"|6
 +
|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S044000 290/044]</u></font>
 +
|USPC
 +
|Prime-mover dynamo plants / electric control / Fluid-current motors / '''Wind '''
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S055000 290/055]</u></font>
 +
|bgcolor = "#DCE6F1"|USPC
 +
|bgcolor = "#DCE6F1"|Prime-mover dynamo plants / Fluid-current motors / '''Wind'''
 +
|-valign="top"
 +
|align = "center"|8
 +
|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc318/sched318.htm#C318S727000 318/727]</u></font>
 +
|USPC
 +
|Electricity: motive power systems / '''Induction motor systems '''
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc322/sched322.htm#C322S047000 322/047]</u></font>
 +
|bgcolor = "#DCE6F1"|USPC
 +
|bgcolor = "#DCE6F1"|Electricity: single generator systems / Generator control / '''Induction generator '''
 
|-
 
|-
−
| style="background-color:#99ccff;border:none;padding:0.079cm;"| <center>'''6'''</center>
 
−
|  <center>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7830127.PN.&OS=PN/7830127&RS=PN/7830127 US7830127B2]</center>
 
−
|  <center>09/11/10</center>
 
−
|  <center>WIND TO POWER SYSTEM S L</center>
 
−
|  Doubly-controlled asynchronous generator
 
 
|}
 
|}
  
−
==Thomson Innovation Search==
+
===Concept Table===
−
A search is carried out using a combination of keywords and classifications in Thomson Innovation.
+
−
The Classifications identified relevant to the scope of the search are:
+
−
 
+
−
===IPC/ ECLA Classes===
+
−
 
+
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
−
|align = "center" bgcolor = "#99ccff"|'''IPC/ ECLA Class'''
+
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
−
|align = "center" bgcolor = "#99ccff"|'''Definition'''
+
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 1'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 2'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 3'''</font>
 
|-
 
|-
−
|align = "center"| F03D9/00
+
|align = "center" bgcolor = "#95B3D7"|'''Doubly Fed'''
−
|Adaptations of wind motors for special use; Combinations of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)
+
|align = "center" bgcolor = "#95B3D7"|'''Induction'''
 +
|align = "center" bgcolor = "#95B3D7"|'''Generator'''
 
|-
 
|-
−
|align = "center"| F03D9/00C
+
|align = "center" bgcolor = "#DCE6F1"|1
−
|Adaptations of wind motors for special use; Combinations of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)/ the apparatus being an electrical generator
+
|bgcolor = "#DCE6F1"|doubly fed
 +
|bgcolor = "#DCE6F1"|induction
 +
|bgcolor = "#DCE6F1"|generator
 
|-
 
|-
−
|align = "center"| H02J3/38
+
|align = "center"|2
−
|Circuit arrangements for ac mains or ac distribution networks/ Arrangements for parallely feeding a single network by two or more generators, converters or transformers
+
|double output
 +
|asynchronous
 +
|machines
 
|-
 
|-
−
|align = "center"| H02K17/42
+
|align = "center" bgcolor = "#DCE6F1"|3
−
|DYNAMO-ELECTRIC MACHINES/ Asynchronous induction motors; Asynchronous induction generators/ Asynchronous induction generators
+
|bgcolor = "#DCE6F1"|dual fed
 +
|bgcolor = "#DCE6F1"|
 +
|bgcolor = "#DCE6F1"|systems
 
|-
 
|-
−
|align = "center"| H02P9/00
+
|align = "center"|4
−
|CONTROL OR REGULATION OF ELECTRIC MOTORS, GENERATORS, OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS / Arrangements for controlling electric generators for the purpose of obtaining a desired output
+
|dual feed
 +
|
 +
|
 +
|-
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|dual output
 +
|bgcolor = "#DCE6F1"|
 +
|bgcolor = "#DCE6F1"|
 
|-
 
|-
 
|}
 
|}
  
−
===US Classes===
+
===Thomson Innovation Search===
 +
'''Database:''' Thomson Innovation<br>
 +
'''Patent coverage:''' US EP WO JP DE GB FR CN KR DWPI<br>
 +
'''Time line:''' 01/01/1836 to 07/03/2011
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Scope'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Search String'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. of Hits'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|Doubly-fed Induction Generator: Keywords(broad)
 +
|bgcolor = "#DCE6F1"|Claims, Title, and Abstract
 +
|bgcolor = "#DCE6F1"|(((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>4 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3)) NEAR5 (induction OR asynchronous)) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR dfig or doig)
 +
|align = "right" bgcolor = "#DCE6F1"|873
 +
|-valign="top"
 +
|align = "center"|2
 +
|Doubly-fed Induction Generator: Keywords(broad)
 +
|Full Spec.
 +
|(((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>1 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3)) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1))) OR dfig or doig)
 +
|align = "center"|<nowiki>-</nowiki>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|Induction Machine: Classes
 +
|bgcolor = "#DCE6F1"|US, IPC, and ECLA Classes
 +
|bgcolor = "#DCE6F1"|((318/727 OR 322/047) OR (H02K001742))
 +
|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 +
|-valign="top"
 +
|align = "center"|4
 +
|Generators: Classes
 +
|US, IPC, and ECLA Classes
 +
|((290/044 OR 290/055) OR (F03D000900C OR H02J000338 OR F03D0009<nowiki>*</nowiki> OR H02P0009<nowiki>*</nowiki>))
 +
|align = "center"|<nowiki>-</nowiki>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|Combined Query
 +
|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 +
|align = "left" bgcolor = "#DCE6F1"|2 AND 3
 +
|align = "right" bgcolor = "#DCE6F1"|109
 +
|-valign="top"
 +
|align = "center"|6
 +
|Combined Query
 +
|align = "center"|<nowiki>-</nowiki>
 +
|align = "left"|2 AND 4
 +
|align = "right"|768
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|French Keywords
 +
|bgcolor = "#DCE6F1"|Claims, Title, and Abstract
 +
|bgcolor = "#DCE6F1"|((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two OR deux) NEAR4 (nourris OR feed<nowiki>*</nowiki>3 OR puissance OR sortie<nowiki>*</nowiki>1 OR contrôle<nowiki>*</nowiki>1)) NEAR4 (induction OR asynchron<nowiki>*</nowiki>1) NEAR4 (générateur<nowiki>*</nowiki>1 OR generator<nowiki>*</nowiki>1 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR dfig or doig)
 +
|align = "right" bgcolor = "#DCE6F1"|262
 +
|-valign="top"
 +
|align = "center"|8
 +
|German Keywords
 +
|Claims, Title, and Abstract
 +
|(((((doppel<nowiki>*</nowiki>1 OR dual OR two OR zwei) ADJ3 (ausgang OR ausgänge OR kontroll<nowiki>*</nowiki> OR control<nowiki>*</nowiki>4 OR gesteuert OR macht OR feed<nowiki>*</nowiki>1 OR gefüttert OR gespeiste<nowiki>*</nowiki>1)) OR (doppeltgefüttert OR doppeltgespeiste<nowiki>*</nowiki>1)) NEAR4 (((induktion OR asynchronen) NEAR4 (generator<nowiki>*</nowiki>2 OR maschine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR (induktion?maschinen OR induktion?generatoren OR asynchronmaschine OR asynchrongenerator))) OR dfig)
 +
|align = "right"|306
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|Doubly-fed Induction Generator: Keywords(narrow)
 +
|bgcolor = "#DCE6F1"|Full Spec.
 +
|bgcolor = "#DCE6F1"|(((((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>4 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3))) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1))) SAME wind) OR (dfig SAME wind))
 +
|align = "right" bgcolor = "#DCE6F1"|1375
 +
|-valign="top"
 +
|align = "center"|10
 +
| Top Assignees
 +
|align = "center"|<nowiki>-</nowiki>
 +
|(vestas* OR (gen* ADJ2 electric*) OR ge OR hitachi OR woodward OR repower OR areva OR gamesa OR ingeteam OR nordex OR siemens OR (abb ADJ2 research) OR (american ADJ2 superconductor*) OR (korea ADJ2 electro*) OR (univ* NEAR3 navarra) OR (wind OR technolog*) OR (wind ADJ2 to ADJ2 power))
 +
|align = "center"|-
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|11
 +
|bgcolor = "#DCE6F1"|Combined Query
 +
|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 +
|bgcolor = "#DCE6F1"|2 AND 10
 +
|align = "right" bgcolor = "#DCE6F1"|690
 +
|-valign="top"
 +
|align = "center"|12
 +
|Top Inventors
 +
|align = "center"|<nowiki>-</nowiki>
 +
|((Andersen NEAR2 Brian) OR (Engelhardt NEAR2 Stephan) OR (Ichinose NEAR2 Masaya) OR (Jorgensen NEAR2 Allan NEAR2 Holm) OR ((Scholte ADJ2 Wassink) NEAR2 Hartmut) OR (OOHARA NEAR2 Shinya) OR (Rivas NEAR2 Gregorio) OR (Erdman NEAR2 William) OR (Feddersen NEAR2 Lorenz) OR (Fortmann NEAR2 Jens) OR (Garcia NEAR2 Jorge NEAR2 Martinez) OR (Gertmar NEAR2 Lars) OR (KROGH NEAR2 Lars) OR (LETAS NEAR2 Heinz NEAR2 Hermann) OR (Lopez NEAR2 Taberna NEAR2 Jesus) OR (Nielsen NEAR2 John) OR (STOEV NEAR2 Alexander) OR (W?ng NEAR2 Haiqing) OR (Yuan NEAR2 Xiaoming))
 +
|align = "center"|-
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|13
 +
|bgcolor = "#DCE6F1" |Combined Query
 +
|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 +
|bgcolor = "#DCE6F1"|((3 OR 4) AND 10)
 +
|align = "right" bgcolor = "#DCE6F1"|899
 +
|-valign="top"
 +
|align = "center"|14
 +
|Final Query
 +
|align = "center"|<nowiki>-</nowiki>
 +
|1 OR 5 OR 6 OR 7 OR 8 OR 9 OR 11 OR 13
 +
|'''2466(1060 INPADOC Families)'''
 +
|-
 +
|}
  
 +
==Taxonomy==
 +
*''Use the mouse(click and drag/scroll up or down/click on nodes) to explore nodes in the detailed taxonomy''
 +
*''Click on the red arrow adjacent to the node name to view the content for that particular node in the dashboard''
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
−
|align = "center" bgcolor = "#99ccff"|'''US Class'''
+
|<mm>[[Doubly_fed_Induction_Generator.mm|Interactive Mind-map|center|flash|Doubly-fed Induction Generator|600pt]]</mm>
−
|align = "center" bgcolor = "#99ccff"|'''Definition'''
+
|}
 +
 
 +
==Sample Analysis==
 +
A sample of 139 patents from the search is analyzed based on the taxonomy.
 +
Provided a link below for sample spread sheet analysis for doubly-fed induction generators.<br>
 +
===Patent Analysis===
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="38"|<font color="#FFFFFF">'''S.No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD" rowspan = "2" |<font color="#FFFFFF">'''Patent/Publication No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="105"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
 +
|align = "center" bgcolor = "#4F81BD" rowspan = "2"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
 +
|align = "center" bgcolor = "#4F81BD" rowspan = "2"|<font color="#FFFFFF">'''Title'''</font>
 +
|align = "center" bgcolor = "#4F81BD" colspan = "2"|<font color="#FFFFFF">'''Dolcera Analysis'''</font>
 
|-
 
|-
−
|align = "center"|290/044
+
|align = "center" bgcolor = "#95B3D7"|'''Problem'''
−
|PRIME-MOVER DYNAMO PLANTS/ ELECTRIC CONTROL/ Fluid-current motors / Wind
+
|align = "center" bgcolor = "#95B3D7"|'''Solution'''
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100117605%22.PGNR.&OS=DN/20100117605&RS=DN/20100117605 US20100117605]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|05/13/10
 +
|bgcolor = "#DCE6F1"|Woodward
 +
|bgcolor = "#DCE6F1"|Method of and apparatus for operating a double-fed asynchronous machine in the event of transient mains voltage changes
 +
|bgcolor = "#DCE6F1"|The short-circuit-like currents in the case of transient mains voltage changes lead to a corresponding air gap torque which loads the drive train and transmission lines can damages or reduces the drive train and power system equipments.
 +
|bgcolor = "#DCE6F1"|The method presents that the stator connecting with the network and the rotor with a converter. The converter is formed to set a reference value of electrical amplitude in the rotor, by which a reference value of the electrical amplitude is set in the rotor after attaining a transient mains voltage change, such that the rotor flux approaches the stator flux.
 +
|-valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100045040%22.PGNR.&OS=DN/20100045040&RS=DN/20100045040 US20100045040]</u></font>
 +
|align = "center"|02/25/10
 +
|Vestas Wind Systems
 +
|Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
 +
|The DFIG system has poor damping of oscillations within the flux dynamics due to cross coupling between active and reactive currents, which makes the system potentially unstable under certain circumstances and complicates the work of the rotor current controller. These oscillations can damage the drive train mechanisms.
 +
|A compensation block is arranged, which feeds a compensation control output to the rotor of the generator. The computation unit computes the control output during operation of the turbine to compensate partly for dependencies on a rotor angular speed of locations of poles of a generator transfer function, so that the transfer function is made independent of variations in the speed during operation of the turbine which eliminates the oscillations and increases the efficiency of the wind turbine.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090267572%22.PGNR.&OS=DN/20090267572&RS=DN/20090267572 US20090267572]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|10/29/09
 +
|bgcolor = "#DCE6F1"|Woodward
 +
|bgcolor = "#DCE6F1"|Current limitation for a double-fed asynchronous machine
 +
|bgcolor = "#DCE6F1"|Abnormal currents can damage the windings in the doubly- fed induction generator. Controlling these currents with the subordinate current controllers cannot be an efficient way to extract the maximum amount of active power.
 +
|bgcolor = "#DCE6F1"|The method involves delivering or receiving of a maximum permissible reference value of an active power during an operation of a double-fed asynchronous machine, where predetermined active power and reactive power reference values are limited to a calculated maximum permissible active and reactive power reference values, and hence ensures reliable regulated effect and reactive power without affecting the power adjustment, the rotor is electrically connected to a pulse-controlled inverter by slip rings with a static frequency changer, and thus a tension with variable amplitude and frequency is imposed in the rotor.
 +
|-valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008944%22.PGNR.&OS=DN/20090008944&RS=DN/20090008944 US20090008944]</u></font>
 +
|align = "center"|01/08/09
 +
|Universidad Publica De Navarra
 +
|Method and system of control of the converter of an electricity generation facility connected to an electricity network in the presence of voltage sags in said network
 +
|Double-fed asynchronous generators are very sensitive to the faults that may arise in the electricity network, such as voltage sags. During the sag conditions the current which appears in said converter may reach very high values, and may even destroy it.
 +
|During the event of a voltage sag occurring, the converter imposes a new set point current which is the result of adding to the previous set point current a new term, called demagnetizing current, It is proportional to a value of free flow of a generator stator. A difference between a value of a magnetic flow in the stator of the generator and a value of a stator flow associated to a direct component of a stator voltage is estimated. A value of a preset calculated difference is multiplied by a factor for producing the demagnetizing current.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7355295.PN.&OS=PN/7355295&RS=PN/7355295 US7355295]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|04/08/08
 +
|bgcolor = "#DCE6F1"|Ingeteam Energy
 +
|bgcolor = "#DCE6F1"|Variable speed wind turbine having an exciter machine and a power converter not connected to the grid
 +
|bgcolor = "#DCE6F1"|a) The active switching of the semiconductors of the grid side converter injects undesirable high frequency harmonics to the grid.<br>b) The use of power electronic converters (4) connected to the grid (9) causes harmonic distortion of the network voltage.
 +
|bgcolor = "#DCE6F1"|Providing the way that power is only delivered to the grid through the stator of the doubly fed induction generator, avoiding undesired harmonic distortion. <br>Grid Flux Orientation (GFO) is used to accurately control the power injected to the grid. An advantage of this control system is that it does not depend on machine parameters, which may vary significantly, and theoretical machine models, avoiding the use of additional adjusting loops and achieving a better power quality fed into the utility grid.
 +
|-valign="top"
 +
|align = "center"|6
 +
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080203978%22.PGNR.&OS=DN/20080203978&RS=DN/20080203978 US20080203978]</u></font>
 +
|align = "center"|08/28/08
 +
|Semikron
 +
|Frequency converter for a double-fed asynchronous generator with variable power output and method for its operation
 +
|Optislip circuit with a resistor is used when speed is above synchronous speed, results in heating the resistor and thus the generator leads to limitation of operation in super synchronous range which results in tower fluctuations.
 +
|Providing a back-to-back converter which contains the inverter circuit has direct current (DC) inputs, DC outputs, and a rotor-rectifier connected to a rotor of a dual feed asynchronous generator. A mains inverter is connected to a power grid, and an intermediate circuit connects one of the DC inputs with the DC outputs. The intermediate circuit has a semiconductor switch between the DC outputs, an intermediate circuit condenser between the DC inputs, and a diode provided between the semiconductor switch and the condenser. Thus the system is allowed for any speed of wind  and reduces the tower fluctuations.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070210651%22.PGNR.&OS=DN/20070210651&RS=DN/20070210651 US20070210651]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|09/13/07
 +
|bgcolor = "#DCE6F1"|Hitachi
 +
|bgcolor = "#DCE6F1"|Power converter for doubly-fed power generator system
 +
|bgcolor = "#DCE6F1"|During the ground faults, excess currents is induced in the secondary windings and flows into power converter connected to secondary side and may damage the power converter. Conventional methods of increasing the capacity of the power converter increases system cost, degrade the system and takes time to activate the system to supply power again.
 +
|bgcolor = "#DCE6F1"|The generator provided with a  excitation power converter connected to secondary windings of a doubly-fed generator via impedance e.g. reactor, and a diode rectifier connected in parallel to the second windings of the doubly-fed generator via another impedance. A direct current link of the rectifier is connected in parallel to a DC link of the converter. A controller  outputs an on-command to a power semiconductor switching element of the converter if a value of current flowing in the power semiconductor switching element is a predetermined value or larger.
 +
|-valign="top"
 +
|align = "center"|8
 +
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070132248%22.PGNR.&OS=DN/20070132248&RS=DN/20070132248 US20070132248]</u></font>
 +
|align = "center"|06/14/07
 +
|General Electric
 +
|System and method of operating double fed induction generators
 +
|Wind turbines with double fed induction generators are sensitive to grid faults. Conventional methods are not effective to reduce the shaft stress during grid faults and slow response and using dynamic voltage restorer (DVR) is cost expensive.
 +
|The protection system has a controlled impedance device. Impedance device has bidirectional semiconductors such triac, assembly of thyristors or anti-parallel thyristors. Each of the controlled impedance devices is coupled between a respective phase of a stator winding of a double fed induction generator and a respective phase of a grid side converter. The protection system also includes a controller configured for coupling and decoupling impedance in one or more of the controlled impedance devices in response to changes in utility grid voltage and a utility grid current. High impedance is offered to the grid during network faults to isolate the dual fed wind turbine generator.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060192390%22.PGNR.&OS=DN/20060192390&RS=DN/20060192390 US20060192390]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|08/31/06
 +
|bgcolor = "#DCE6F1"|Gamesa Innovation
 +
|bgcolor = "#DCE6F1"|Control and protection of a doubly-fed induction generator system
 +
|bgcolor = "#DCE6F1"|A short-circuit in the grid causes the generator to feed high stator-currents into the short-circuit and the rotor-currents increase very rapidly which cause damage to the power-electronic components of the converter connecting the rotor windings with the rotor-inverter.
 +
|bgcolor = "#DCE6F1"|The converter is provided with a clamping unit which is triggered from a non-operation state to an operation state, during detection of over-current in the rotor windings. The clamping unit comprises passive voltage-dependent resistor element for providing a clamping voltage over the rotor windings when the clamping unit is triggered.
 +
|-valign="top"
 +
|align = "center"|10
 +
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220050189896%22.PGNR.&OS=DN/20050189896&RS=DN/20050189896 US20050189896]</u></font>
 +
|align = "center"|09/01/05
 +
|ABB Research
 +
|Method for controlling doubly-fed machine
 +
|Controlling the double fed machines on the basis of inverter control to implement the targets set for the machine, this model is extremely complicated and includes numerous parameters that are often to be determined.
 +
|A method is provided to use a standard scalar-controlled frequency converter for machine control. A frequency reference for the inverter with a control circuit, and reactive power reference are set for the machine. A rotor current compensation reference is set based on reactive power reference and reactive power. A scalar-controlled inverter is controlled for producing voltage for the rotor of the machine, based on the set frequency reference and rotor current compensation reference.
 
|-
 
|-
−
|align = "center"|290/055
+
|}
−
|PRIME-MOVER DYNAMO PLANTS/ FLUID-CURRENT MOTORS/ Wind
+
Click '''[[Media:Doublyfed_induction_generator1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators patent analysis.
 +
 
 +
===Article Analysis===
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S.No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
 +
|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Dolcera Summary'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=1709031&queryText=Study+on+the+Control+of+DFIG+and+Its+Responses+to+Grid+Disturbances&openedRefinements=*&searchField=Search+All Study on the Control of DFIG and its Responses to Grid Disturbances ]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|01/01/06
 +
|bgcolor = "#DCE6F1"|Power Engineering Society General Meeting, 2006. IEEE
 +
|bgcolor = "#DCE6F1"|Presented dynamic model of the DFIG, including mechanical model, generator model, and PWM voltage source converters. Vector control strategies adapted for both the RSC and GSC to control speed and reactive power independently. Control designing methods, such as pole-placement method and the internal model control are used. MATLAB/Simulink is used for simulation.
 +
|-valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=1649950&queryText=Application+of+Matrix+Converter+for+Variable+Speed+Wind+Turbine+Driving+an+Doubly+Fed+Induction+Generator&openedRefinements=*&searchField=Search+All Application of Matrix Converter for Variable Speed Wind Turbine Driving an Doubly Fed Induction Generator ]</u></font>
 +
|align = "center"|05/23/06
 +
|Power Electronics, Electrical Drives, Automation and Motion, 2006. SPEEDAM 2006.
 +
|A matrix converter is replaced with back to back converter in a variable speed wind turbine using doubly fed induction generator. Stable operation is achieved by stator flux oriented control technique and the system operated in both sub and super synchronous modes, achieved good results.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=4778305&queryText=Optimal+Power+Control+Strategy+of+Maximizing+Wind+Energy+Tracking+and+Conversion+for+VSCF+Doubly+Fed+Induction+Generator+System&openedRefinements=*&searchField=Search+Al Optimal Power Control Strategy of Maximizing Wind Energy Tracking and Conversion for VSCF Doubly Fed Induction Generator System ]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|08/14/06
 +
|bgcolor = "#DCE6F1"|Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International
 +
|bgcolor = "#DCE6F1"|Proposed a new optimal control strategy of maximum wind power extraction strategies and testified by simulation. The control algorithm also used to minimize the losses in the generator. The dual passage excitation control strategy is applied to decouple the active and reactive powers. With this control system, the simulation results show the good robustness and high generator efficiency is achieved.
 +
|-valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://docs.google.com/viewer?a=v&q=cache:HqaFsMBhchcJ:iris.elf.stuba.sk/JEEEC/data/pdf/3_108-8.pdf+A+TORQUE+TRACKING+CONTROL+ALGORITHM+FOR+DOUBLY–FED+INDUCTION+GENERATOR&hl=enπd=bl&srcid=ADGEESgbHXoAbKe4O7b5DnykDc7h_LaHwCMIhkVrGX_whx4iUuE4Mc-3Rfq1DyW_h A Torque Tracking Control algorithm for Doubly–fed Induction Generator ]</u></font>
 +
|align = "center"|01/01/08
 +
|Journal of Electrical Engineering
 +
|Proposed a torque tracking control algorithm for Doubly fed induction generator using PI controllers. It is achieved by controlling the rotor currents and using a stator voltage vector reference frame.
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=4651578&queryText=Fault+Ride+Through+Capability+Improvement+Of+Wind+Farms+Usind+Doubly+Fed+Induciton+Generator&openedRefinements=*&searchField=Search+All Fault Ride Through Capability Improvement Of Wind Farms Using Doubly Fed Induction Generator ]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|09/04/08
 +
|bgcolor = "#DCE6F1"|Universities Power Engineering Conference, 2008. UPEC 2008. 43rd International
 +
|bgcolor = "#DCE6F1"|An active diode bridge crowbar switch presented to improve fault ride through capability of DIFG. Showed different parameters related to crowbar such a crowbar resistance, power loss, temperature and time delay for deactivation during fault.
 
|-
 
|-
−
|align = "center"|318/727
+
|}
−
|ELECTRICITY: MOTIVE POWER SYSTEMS/ INDUCTION MOTOR SYSTEMS
+
Click '''[[Media:Doublyfed_induction_generators1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators article analysis.
 +
<br>
 +
 
 +
===Top Cited Patents===
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Patent/Publication No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''Publication Date'''<br>(mm/dd/yyyy)</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Citation Count'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5289041.PN.&OS=PN/5289041&RS=PN/5289041 US5289041]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|02/22/94
 +
|bgcolor = "#DCE6F1"|US Windpower
 +
|bgcolor = "#DCE6F1"|Speed control system for a variable speed wind turbine
 +
|align = "center" bgcolor = "#DCE6F1"|80
 +
|-valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4982147.PN.&OS=PN/4982147&RS=PN/4982147 US4982147]</u></font>
 +
|align = "center"|01/01/91
 +
|Oregon State
 +
|Power factor motor control system
 +
|align = "center"|62
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5028804.PN.&OS=PN/5028804&RS=PN/5028804 US5028804]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|07/02/91
 +
|bgcolor = "#DCE6F1"|Oregon State
 +
|bgcolor = "#DCE6F1"|Brushless doubly-fed generator control system
 +
|align = "center" bgcolor = "#DCE6F1"|51
 +
|-valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5239251.PN.&OS=PN/5239251&RS=PN/5239251 US5239251]</u></font>
 +
|align = "center"|08/24/93
 +
|Oregon State
 +
|Brushless doubly-fed motor control system
 +
|align = "center"|49
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6856038.PN.&OS=PN/6856038&RS=PN/6856038 US6856038]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|02/15/05
 +
|bgcolor = "#DCE6F1"|Vestas Wind Systems
 +
|bgcolor = "#DCE6F1"|Variable speed wind turbine having a matrix converter
 +
|align = "center" bgcolor = "#DCE6F1"|43
 +
|-valign="top"
 +
|align = "center"|6
 +
|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=1999029034 WO1999029034]</u></font>
 +
|align = "center"|06/10/99
 +
|Asea Brown
 +
|A method and a system for speed control of a rotating electrical machine with flux composed of two quantities
 +
|align = "center"|36
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=1999019963 WO1999019963]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|04/22/99
 +
|bgcolor = "#DCE6F1"|Asea Brown
 +
|bgcolor = "#DCE6F1"|Rotating electric machine
 +
|align = "center" bgcolor = "#DCE6F1"|36
 +
|-valign="top"
 +
|align = "center"|8
 +
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7015595.PN.&OS=PN/7015595&RS=PN/7015595 US7015595]</u></font>
 +
|align = "center"|03/21/06
 +
|Vestas Wind Systems
 +
|Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch control
 +
|align = "center"|34
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4763058.PN.&OS=PN/4763058&RS=PN/4763058 US4763058]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|08/09/88
 +
|bgcolor = "#DCE6F1"|Siemens
 +
|bgcolor = "#DCE6F1"|Method and apparatus for determining the flux angle of rotating field machine or for position-oriented operation of the machine
 +
|align = "center" bgcolor = "#DCE6F1"|32
 +
|-valign="top"
 +
|align = "center"|10
 +
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7095131.PN.&OS=PN/7095131&RS=PN/7095131 US7095131]</u></font>
 +
|align = "center"|08/22/06
 +
|General Electric
 +
|Variable speed wind turbine generator
 +
|align = "center"|25
 
|-
 
|-
−
|align = "center"|322/047
+
|}
−
|ELECTRICITY: SINGLE GENERATOR SYSTEMS/ GENERATOR CONTROL/ Induction generator
+
===Top Cited Articles===
 +
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 +
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Publication Date'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>
 +
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Citations Count'''</font>
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|1
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=502360 Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|May. 1996
 +
|bgcolor = "#DCE6F1"|IEEE Proceedings Electric Power Applications
 +
|align = "center" bgcolor = "#DCE6F1"|906
 +
|-valign="top"
 +
|align = "center"|2
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=999610 Doubly fed induction generator systems for wind turbines]</u></font>
 +
|align = "center"|May. 2002
 +
|IEEE Industry Applications Magazine
 +
|align = "center"|508
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|3
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=1198317 Dynamic modeling of doubly fed induction generator wind turbines]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|May. 2003
 +
|bgcolor = "#DCE6F1"|IEEE Transactions on Power Systems
 +
|align = "center" bgcolor = "#DCE6F1"|274
 +
|-valign="top"
 +
|align = "center"|4
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1201089 Modeling and control of a wind turbine driven doubly fed induction generator]</u></font>
 +
|align = "center"|Jun. 2003
 +
|IEEE Transactions on Energy Conversion
 +
|align = "center"|271
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|5
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/iel5/60/30892/01432858.pdf?arnumber=1432858 Ride through of wind turbines with doubly-fed induction generator during a voltage dip]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|Jun. 2005
 +
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
 +
|align = "center" bgcolor = "#DCE6F1"|246
 +
|-valign="top"
 +
|align = "center"|6
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=970114 Dynamic modeling of a wind turbine with doubly fed induction generator]</u></font>
 +
|align = "center"|July. 2001
 +
|IEEE Power Engineering Society Summer Meeting, 2001
 +
|align = "center"|196
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|7
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1597345 Modeling of the wind turbine with a doubly fed induction generator for grid integration studies]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|Mar. 2006
 +
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
 +
|align = "center" bgcolor = "#DCE6F1"|174
 +
|-valign="top"
 +
|align = "center"|8
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=543631 A doubly fed induction generator using back-to-back PWM converters supplying an isolated load from a variable speed wind turbine]</u></font>
 +
|align = "center"|Sept. 1996
 +
|IEEE Proceedings Electric Power Applications
 +
|align = "center"|150
 +
|-valign="top"
 +
|align = "center" bgcolor = "#DCE6F1"|9
 +
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=1432853 Doubly fed induction generator model for transient stability analysis]</u></font>
 +
|align = "center" bgcolor = "#DCE6F1"|Jun. 2005
 +
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
 +
|align = "center" bgcolor = "#DCE6F1"|106
 +
|-valign="top"
 +
|align = "center"|10
 +
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1677655 Control of a doubly fed induction generator in a wind turbine during grid fault ride-through]</u></font>
 +
|align = "center"|Sept. 2006
 +
|IEEE Transactions on Energy Conversion
 +
|align = "center"|112
 
|-
 
|-
 
|}
 
|}
  
 +
===White Space Analysis===
 +
* White-space analysis provides the technology growth and gaps in the technology where further R&D can be done to gain competitive edge and to carry out incremental innovation.
 +
* Dolcera provides White Space Analysis in different  dimensions. Based on Product, Market, Method of Use, Capabilities or Application or Business Area and defines the exact categories within the dimension.
 +
* Below table shows a sample representation of white space analysis for controlling DFIG parameters with converters, based on the sample analysis.
 +
{|border="2" cellspacing="0" cellpadding="14" width="20%"
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''White Space of converters used to control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Active power'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Reactive Power'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Decoupled P-Q control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Field oriented control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Direct torque control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Speed control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Frequency Control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Pitch control'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''PWM Technique'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Low voltage ride through'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Network fault/Grid fault'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Symmetrical and Asymmetrical Faults'''</font></center>
 +
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Temp control'''</font></center>
  
−
 
−
===Concept Table===
 
−
{|border="2" cellspacing="0" cellpadding="4" width="50%"
 
−
|align = "center" bgcolor = "#99ccff"|'''S.No'''
 
−
|align = "center" bgcolor = "#99ccff"|'''Concept1'''
 
−
|align = "center" bgcolor = "#99ccff"|'''Concept1'''
 
−
|align = "center" bgcolor = "#99ccff"|'''Concept1'''
 
 
|-
 
|-
−
|align = "center"|1
+
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Grid Side active converters'''</font></center>
−
|Doubly fed
+
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1]
−
|Induction
+
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060028025%22.PGNR.&OS=DN/20060028025&RS=DN/20060028025 US20060028025A1]
−
|Generator
+
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100148508%22.PGNR.&OS=DN/20100148508&RS=DN/20100148508 US20100148508A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100133816%22.PGNR.&OS=DN/20100133816&RS=DN/20100133816 US20100133816A1]
 +
[http://v3.espacenet.com/searchResults?NUM=EP2166226A1&DB=EPODOC&submitted=true&locale=en_V3&ST=number&compact=false EP2166226A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070132248%22.PGNR.&OS=DN/20070132248&RS=DN/20070132248 US20070132248A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100096853%22.PGNR.&OS=DN/20100096853&RS=DN/20100096853 US20100096853A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100114388%22.PGNR.&OS=DN/20100114388&RS=DN/20100114388 US20100114388A1]
 +
|
 +
|
 +
| style="background-color:#ffffff;"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
 +
| style="background-color:#ffffff;"| [http://www.wipo.int/pctdb/en/wo.jsp?WO=2010079234 WO2010079234A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090230689%22.PGNR.&OS=DN/20090230689&RS=DN/20090230689 US20090230689A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090206606%22.PGNR.&OS=DN/20090206606&RS=DN/20090206606 US20090206606A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070024247%22.PGNR.&OS=DN/20070024247&RS=DN/20070024247 US20070024247A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090206606%22.PGNR.&OS=DN/20090206606&RS=DN/20090206606 US20090206606A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080129050%22.PGNR.&OS=DN/20080129050&RS=DN/20080129050 US20080129050A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100156192%22.PGNR.&OS=DN/20100156192&RS=DN/20100156192 US20100156192A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070182383%22.PGNR.&OS=DN/20070182383&RS=DN/20070182383 US20070182383A1]
 +
| style="background-color:#ffffff;"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100002475%22.PGNR.&OS=DN/20100002475&RS=DN/20100002475 US20100002475A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080296898%22.PGNR.&OS=DN/20080296898&RS=DN/20080296898 US20080296898A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070273155%22.PGNR.&OS=DN/20070273155&RS=DN/20070273155 US20070273155A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070278797%22.PGNR.&OS=DN/20070278797&RS=DN/20070278797 US20070278797A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052244%22.PGNR.&OS=DN/20070052244&RS=DN/20070052244 US20070052244A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070024059%22.PGNR.&OS=DN/20070024059&RS=DN/20070024059 US20070024059A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060238929%22.PGNR.&OS=DN/20060238929&RS=DN/20060238929 US20060238929A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070177314%22.PGNR.&OS=DN/20070177314&RS=DN/20070177314 US20070177314A1]
 +
| style="background-color:#ffffff;"|[http://v3.espacenet.com/searchResults?NUM=EP2166226A1&DB=EPODOC&submitted=true&locale=en_V3&ST=number&compact=false EP2166226A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090121483%22.PGNR.&OS=DN/20090121483&RS=DN/20090121483 US20090121483A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
 
|-
 
|-
−
|align = "center"|2
+
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Grid side passive converters'''</font></center>
−
|Double output
+
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220030151259%22.PGNR.&OS=DN/20030151259&RS=DN/20030151259 US20030151259A1]
−
|Asynchronous
+
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220030151259%22.PGNR.&OS=DN/20030151259&RS=DN/20030151259 US20030151259A1]
−
|Machines
+
−
|-
+
−
|align = "center"|3
+
−
|Dual fed
+
 
|
 
|
−
|Systems
+
|
 +
|
 +
|
 +
|
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220030151259%22.PGNR.&OS=DN/20030151259&RS=DN/20030151259 US20030151259A1]
 +
|
 +
|
 +
|
 +
|
 +
|
 +
 
 
|-
 
|-
−
|align = "center"|4
+
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Rotor side converter'''</font></center>
−
|Dual feed
+
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100142237%22.PGNR.&OS=DN/20100142237&RS=DN/20100142237 US20100142237A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060028025%22.PGNR.&OS=DN/20060028025&RS=DN/20060028025 US20060028025A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100096853%22.PGNR.&OS=DN/20100096853&RS=DN/20100096853 US20100096853A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100148508%22.PGNR.&OS=DN/20100148508&RS=DN/20100148508 US20100148508A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100133816%22.PGNR.&OS=DN/20100133816&RS=DN/20100133816 US20100133816A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070132248%22.PGNR.&OS=DN/20070132248&RS=DN/20070132248 US20070132248A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100114388%22.PGNR.&OS=DN/20100114388&RS=DN/20100114388 US20100114388A1]
 
|
 
|
 
|
 
|
 +
| style="background-color:#ffffff;"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
 +
| style="background-color:#ffffff;"|[http://www.wipo.int/pctdb/en/wo.jsp?WO=2010079234 WO2010079234A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090230689%22.PGNR.&OS=DN/20090230689&RS=DN/20090230689 US20090230689A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070024247%22.PGNR.&OS=DN/20070024247&RS=DN/20070024247 US20070024247A1]
 +
| style="background-color:#ffffff;"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080129050%22.PGNR.&OS=DN/20080129050&RS=DN/20080129050 US20080129050A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070182383%22.PGNR.&OS=DN/20070182383&RS=DN/20070182383 US20070182383A1]
 +
| style="background-color:#ffffff;"|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100002475%22.PGNR.&OS=DN/20100002475&RS=DN/20100002475 US20100002475A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080296898%22.PGNR.&OS=DN/20080296898&RS=DN/20080296898 US20080296898A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070273155%22.PGNR.&OS=DN/20070273155&RS=DN/20070273155 US20070273155A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070278797%22.PGNR.&OS=DN/20070278797&RS=DN/20070278797 US20070278797A1]
 +
| style="background-color:#ffffff;"|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080157533%22.PGNR.&OS=DN/20080157533&RS=DN/20080157533 US20080157533A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052244%22.PGNR.&OS=DN/20070052244&RS=DN/20070052244 US20070052244A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070024059%22.PGNR.&OS=DN/20070024059&RS=DN/20070024059 US20070024059A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060238929%22.PGNR.&OS=DN/20060238929&RS=DN/20060238929 US20060238929A1]
 +
| style="background-color:#ffffff;"|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090273185%22.PGNR.&OS=DN/20090273185&RS=DN/20090273185 US20090273185A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070177314%22.PGNR.&OS=DN/20070177314&RS=DN/20070177314 US20070177314A1]
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090121483%22.PGNR.&OS=DN/20090121483&RS=DN/20090121483 US20090121483A1]
 +
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
 
|-
 
|-
−
|align = "center"|5
+
| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Matrix converters'''</font></center>
−
|Dual output
+
|
 +
| style="background-color:#ffffff;"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220020079706%22.PGNR.&OS=DN/20020079706&RS=DN/20020079706 US20020079706A1]
 +
|
 +
|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070216164%22.PGNR.&OS=DN/20070216164&RS=DN/20070216164 US20070216164A1]
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|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090265040%22.PGNR.&OS=DN/20090265040&RS=DN/20090265040 US20090265040A1]
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|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070216164%22.PGNR.&OS=DN/20070216164&RS=DN/20070216164 US20070216164A1]
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===Search Strategy===
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== Dolcera Dashboard ==
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[[Image:dashboard_features.png|center|750px|]]
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The databases covered in the search include: US Grant, GB App, US App, FR App, WO App, DE Util, EP Grant, DE Grant, EP App, DE App, JP Util, JP Grant, JP App, CN Util, CN App, KR Util , KR Grant, KR App, Other, DWPI
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'''Dashboard Link'''<br>
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
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|align = "center" bgcolor = "#99ccff"|'''S.No'''
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|'''[https://www.dolcera.com/auth/dashboard/dashboard.php?workfile_id=825 Doubly Fed Induction Generator - Dashboard] '''
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|align = "center" bgcolor = "#99ccff"|'''No. of Hits'''
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|width="100"|[[Image:dashboard_thumb.png|center|100px|]]
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|align = "center" bgcolor = "#99ccff"|'''Remarks'''
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|align = "center" bgcolor = "#99ccff"|'''Search String'''
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|-
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|align = "center"|1
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|align = "center"|795 hits
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|Doubly fed induction generator keywords
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|CTB=(((((Doubl*3 or dual*3 or two) adj3 (power*2 or output*4 or control*4 or fed or feed*3)) near5 (induction or asynchronous)) near5 (generat*3 or machine*1 or dynamo*1)) OR DFIG);
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|-
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|align = "center"|2
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|align = "center"|93 hits
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|Induction motor classes AND Doubly fed generator keywords
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|(UC=(318/727 OR 322/047) OR AIOE=(H02K001742)) AND ALL=(((((Doubl*3 or dual*3 or two) adj3 (power*2 or output*1 or control*4 or fed or feed*3)) near5 (generat*3 or machine*1 or dynamo*1))) OR DFIG);
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|-
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|align = "center"|3
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|align = "center"|675 hits
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|Broad classes of generators AND Doubly fed induction generator keywords
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|(UC=(290/044 OR 290/055) OR AIOE=(F03D000900C OR H02J000338 OR F03D0009* OR H02P0009*)) AND ALL=(((((Doubl*2 or dual*3 or two) adj3 (power*2 or output*1 or control*3 or fed or feed*3)) near5 (induction or asynchronous)) near5 (generat*3 or machine*1 or dynamo*1)) or DFIG);
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|-
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|align = "center"|4
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|align = "center"|240 hits
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|French keywords
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| CTB=((((Doubl*3 or dual*3or ADJ two or deux) near4 (nourris or feed*3 or puissance or sortie*1 or contrôle*1)) near4 (induction or asynchrone*1) near4 (générateur*1 or generator*1 or machine*1 or dynamo*1)) or DFIG);
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|align = "center"|5
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|align = "center"|282 hits
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|German keywords
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|CTB=(((((doppel*1 or dual or two or zwei) adj3 (Ausgang or Ausgänge or Kontroll* or control*4 or gesteuert or Macht or feed*1 or gefüttert or gespeiste*1)) or (doppeltgefüttert or DOPPELTGESPEISTE*1)) near4 (((Induktion or asynchronen) near4 (generator*2 or Maschine*1 or dynamo*1)) or (INDUKTION?MASCHINEN or INDUKTION?generatoren or Asynchronmaschine or Asynchrongenerator))) or DFIG);
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|align = "center"|6
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|align = "center"|920 hits
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|ALL=(((((((Doubl*3 or dual*3) adj3 (power*2 or output*4 or control*4 or fed or feed*3))) near5 (generat*3 or machine*1 or dynamo*1))) same wind) or (DFIG same wind)) AND DP>=(18360101);
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|align = "center"|7
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|align = "center"|'''1434 hits (702 INPADOC Families)'''
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|Combined Query
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|1 OR 2 OR 3 OR 4 OR 5 OR 6
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*Flash Player is essential to view the Dolcera dashboard
  
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==Taxonomy==
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==Key Findings==
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<mm>[[mmap825(1.1)_1.mm|Interactive Mindmap|center|title Doubly-fed Induction Generator]]</mm>
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=== Major Players ===
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* [http://www.vestas.com/ Vestas Wind Energy Systems] and [http://www.ge.com/ General Electric] are the major players in wind energy generation technology.
 +
[[Image:Wind_Major_Players.png|center|thumb|700px|'''Major Players''']]
  
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==Sample Analysis==
+
=== Key Patents ===
−
A sample of 139 patents from the search are analysed based on the taxonomy.
+
* The key patents in the field are held by [http://www.windpoweringamerica.gov/wind_installed_capacity.asp US Windpower], [http://www.oregon.gov/ENERGY/RENEW/Wind/windhome.shtml Oregon State] and [http://www.vestas.com/ Vestas Wind Energy Systems].
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Provided a link below for sample spread sheet analysis for doubly-fed induction generators.<br>
+
  
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* [[Media:Doublyfed_induction_generator1.xls| Sample analysis on Doubly-Fed Induction Generator-Patent Literature]]<br>
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[[Image:wind_top_cited.png|center|thumb|700px|'''Key Patents''']]
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* [[Media:Doublyfed_induction_generators1.xls| Sample analysis on Doubly-Fed Induction Generator-Non Patent Literature]]
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==IP Trend Analysis==
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=== IP Activity ===
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Patenting activity has seen high growth rate in the last two years.
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* Patenting activity has seen a very high growth rate in the last two years.
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[[Image:ipublication trends.png|center|750px]]
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[[Image:ind_pat_act_3.png|center|thumb|700px|'''Year wise IP Activity''']]
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Vestas Wind Systems and General Electric are the major players in this technology field.
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[[Image:Major Players.png|center|750px]]
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==Dashboard==
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=== Geographical Activity ===
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[[Image:Dashboard12.jpg|center|750px|]]
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* USA, China, Germany, Spain, and India are very active in wind energy research.
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[[Image:wind_geographical_act.png|center|thumb|700px|'''Geographical Activity''']]
  
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'''Dashboard Link'''<br>
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=== Research Trend ===
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[http://client.dolcera.com/dashboard/dashboard.html?workfile_id=825 Dashboard for doubly fed induction generator]
+
* Around 86% patents are on controlling the doubly-fed induction generation(DFIG) which indicates high research activity going on in rating and controlling of the DFIG systems.
  
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*Flash Player is essential to view the Dashboard
+
=== Issues in the Technology ===
 +
* 86% of the patent on DFIG operation are focusing on grid connected mode of operation, suggesting continuous operation of the DFIG system during weak and storm winds, grid voltage sags, and grid faults are major issues in the current scenario.
  
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=Market Research=
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[[Image:Windenergyanalysis.jpg|center|1200px|thumb|'''Problem Solution Mapping''']]
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==Major Players==
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−
Vestas Wind Systems, General Electric and Gamesa Innovation & Technology are the top players in terms of installed power capacity in the year 2007.
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{| border="2" cellspacing="0" cellpadding="4"
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| style="background-color:#99ccff;padding:0.079cm;"| <center>'''S.No'''</center>
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| style="background-color:#99ccff;padding:0.079cm;"| <center>'''Company'''</center>
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| colspan="2"  style="background-color:#99ccff;padding:0.079cm;"| <center>'''Installed Capacity'''</center>
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|-
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| style="padding:0.079cm;"| <center>1</center>
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| style="padding:0.079cm;"| <center>Vestas (Denmark)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>4,500 MW</center>
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|-
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| style="padding:0.079cm;"| <center>2</center>
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| style="padding:0.079cm;"| <center>GE Energy (United States)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>3,300 MW</center>
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|-
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| style="padding:0.079cm;"| <center>3</center>
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| style="padding:0.079cm;"| <center>Gamesa (Spain)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>3,050 MW</center>
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|-
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| style="padding:0.079cm;"| <center>4</center>
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| style="padding:0.079cm;"| <center>Enercon (Germany)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>2,700 MW</center>
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|-
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| style="padding:0.079cm;"| <center>5</center>
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| style="padding:0.079cm;"| <center>Suzlon (India)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>2,000 MW</center>
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|-
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| style="padding:0.079cm;"| <center>6</center>
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| style="padding:0.079cm;"| <center>Siemens (Denmark / Germany)</center>
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| colspan="2"  style="padding:0.079cm;"| <center>1,400 MW</center>
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|-
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| style="padding:0.079cm;"| <center>7</center>
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| style="padding:0.079cm;"| <center>Acciona (Spain)</center>
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| style="padding:0.079cm;"| <center>870 MW</center>
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|-
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| style="padding:0.079cm;"| <center>8</center>
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| style="padding:0.079cm;"| <center>Goldwind (China - PRC)</center>
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| style="padding:0.079cm;"| <center>830 MW</center>
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|-
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| style="padding:0.079cm;"| <center>9</center>
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| style="padding:0.079cm;"| <center>Nordex (Germany)</center>
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| style="padding:0.079cm;"| <center>670 MW</center>
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|-
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| style="padding:0.079cm;"| <center>10</center>
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| style="padding:0.079cm;"| <center>Sinovel (China - PRC)</center>
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| style="padding:0.079cm;"| <center>670 MW</center>
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|}
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−
Source:[http://www.mywindpowersystem.com/2009/04/the-10-major-wind-power-companies-in-the-world/ Wind power companies]
+
=== Emerging Player ===
 +
* [http://www.woodward.com/ Woodward] is a new and fast developing player in the field of DFIG technology. The company filed 10 patent applications in the field in year 2010, while it has no prior IP activity.
  
−
==Market Overview==
 
−
 
−
 
−
* The world's wind industry defied the economic downturn in 2008 and by he end of the year 2009, the sector saw its annual market grow by 41.5% over 2008, and total global wind power capacity increased by 31.7% to 158GW in 2009
 
−
* US, China and Germany together hold more than 50% of the global wind power capacity
 
−
* Asia and North America have seen tremendous growth in the installed wind power capacity over the last 6 years
 
−
* Asia was the world's largest regional market for wind energy with capacity additions amounting to 15.4GW. China was the world's largest market in 2009, more than doubling its capacity from 12.1GW in 2008 to 25.8GW, adding a staggering 13.8GW of capacity
 
−
* China and the US account for more than 60% of the new installed capacity of 38.3GW in 2009. India's total installed capacity increased to 10.9GW with 1.3GW of new installed capacity in 2009
 
−
* The 2009 market for turbine installations was worth about 45 bn € or 63 bn US$ and about half a million people are now employed by the wind industry around  the world
 
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[[Image:Installed capacity 2009.png|600px|center|thumb|Top 10 Cumulative Installed Capacity 2009]]
 
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[[Image:New capacity.png|600px|center|thumb|Top 10 New Installed Capacity 2009]]
 
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[[Image:Region Capacities.png|600px|center|thumb|Annual Installed Capacity by Region 2003-2009]]
 
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==Market Forecast==
 
−
* Global wind power capacity could reach 2,300 GW by 2030, providing up to 22% of the world's electricity needs, from the existing 2.2% in 2010.
 
−
* Global wind capacity will stand at 409GW up from 158GW at the end of 2008. During 2014, 62.5 GW of new capacity will be added to the global total, compared to 38.3 GW in 2009
 
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* The annual growth rates during this period will average 20.9% in terms of total installed capacity, and 10.3% for annual market growth
 
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* Three regions will continue to drive the expansion of wind energy capacity: Asia, North America and Europe
 
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* Asia will remain the fastest growing market in the world, driven primarily by China, which is set to continue the rapid upscaling of its wind capacity and hold its position as the world’s largest annual market. Annual additions are expected to be well over 20 GW in China by 2014
 
−
* Sustained growth is also expected in India, which will increase its capacity steadily by 2 GW every year, and be
 
−
complemented by growth in other Asian markets, including Japan, Taiwan, South Korea and the Philippines, and potentially some others
 
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* By 2014, the annual market will reach 14.5 GW, and a total of 60 GW will be installed in Europe over this five year period
 
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[[Image:Market forecast.png|800px|center|thumb|ANNUAL MARKET FORECAST BY REGION 2009-2013]]
 
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<br>
 
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Source:[http://www.gwec.net/index.php?id=167 GWEC's Global Wind Report 2009]
 
 
=<span style="color:#C41E3A">Like this report?</span>=
 
=<span style="color:#C41E3A">Like this report?</span>=
 
<p align="center"> '''This is only a sample report with brief analysis''' <br>
 
<p align="center"> '''This is only a sample report with brief analysis''' <br>
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<br>
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=References =
 +
{|border="0" cellspacing="0" cellpadding="4" width="100%"
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|-valign="top"
 +
|'''Background References'''
 +
# [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx Wind Energy History]
 +
# [[Media:windenergy.pdf| Wind Energy]]
 +
# [http://windeis.anl.gov/guide/basics/index.cfm Wind Energy Basics]
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# [http://www1.eere.energy.gov/windandhydro/wind_how.html#inside How Wind Turbines Work]
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# [http://www.windpowertv.com/forum/index.php?topic=18.0 Different types of wind turbines]
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# [http://www.house-energy.com/Wind/Offshore-Onshore.htm Onshore Vs Offshore Wind Turbines]
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# [http://library.thinkquest.org/06aug/01335/wind%20Power.htm Wind Power]
 +
# [http://www.ehow.com/list_5938067_types-wind-farms-there_.html Types of Wind Farms]
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# [http://www.offshorewindenergy.org/ca-owee/indexpages/Offshore_technology.php?file=offtech_p2.php Offshore Technology]
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# [http://windsine.org/?act=spage&f=wind The Fundamentals of Wind Energy]
 +
# [http://windertower.com/ Winder Tower]
 +
# [http://www.thesolarguide.com/wind-power/wind-towers.aspx Wind Towers]
 +
# [http://guidedtour.windpower.org/en/tour/design/concepts.htm Wind Turbine Blades]
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# [http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Wind Turbine Design Styles]
 +
# [http://www.awewind.com/Products/TurbineConstruction/MainAssembly/RotorHub/tabid/81/Default.aspx Rotor Hub Assembly]
 +
# [http://www.gears-gearbox.com/wind-turbines.html Gearbox for Wind Turbines]
 +
# [http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
 +
# [http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
 +
# [[Media:windturbinegenerators.pdf| Wind Turbine Generators]]
 +
# [http://www.uni-hildesheim.de/~irwin/inside_wind_turbines.html Inside wind turbines]
 +
|'''Image References'''
 +
# [http://www.windsimulators.co.uk/DFIG.htm DFIG Working Principle]
 +
# [http://www.wwindea.org/home/index.php  Country share of total capacity]
 +
# [http://www.atlantissolar.com/wind_story.html Wind turbine principle]
 +
# [http://www.windturbinesnow.com/horizontalaxis-windturbines.htm Horizontal axis wind turbine]
 +
# [http://www.solarpowerwindenergy.org/2009/12/25/types-of-wind-turbines/ Vertical axis wind turbine]
 +
# [http://zone.ni.com/devzone/cda/tut/p/id/8189 Pitch control]
 +
# [http://zone.ni.com/devzone/cda/tut/p/id/8189 Yaw control]
 +
# [http://www.eco-trees.org/europes-biggest-onshore-wind-farm-goes-online/ Onshore Wind turbines]
 +
# [http://www.house-energy.com/Wind/Offshore-Onshore.htm Offshore wind turbines]
 +
# [http://www.solarpowerwindenergy.org/2010/04/02/parts-of-a-wind-turbine/ Wind turbine parts]
 +
# [http://www.windsolarenergy.org/map-of-best-locations-for-wind-power.htm Tower height Vs Power output]
 +
# [http://americanrenewableenergycorp.com/towers Tubular tower]
 +
# [http://www.mywindpowersystem.com/2010/03/wind-power-stats-quiet-critics/ Lattice tower]
 +
# [http://itgiproducts.com/energy/windTowers.asp Guy tower]
 +
# [http://itgiproducts.com/energy/windTowers.asp Tiltup tower]
 +
# [http://itgiproducts.com/energy/windTowers.asp Free stand tower]
 +
# [http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Single blade turbine]
 +
# [http://www.trendir.com/green/?start=15 Two blade turbine]
 +
# [http://www.china-windturbine.com/wind-turbines-blades.htm Three blade turbine]
 +
# [http://windturbinesforthehome.com/ Internal nacelle structure]
 +
# [http://syigroup.en.made-in-china.com/product/dbTQyzJOHYRi/China-Iron-Casting-Wind-Mill-Tower-Rotor-Hub.html Rotor hub]
 +
# [http://jiangyinzkforging.en.made-in-china.com/product/hewxIQjbgTpr/China-Wind-Turbine-Shaft-For-Wind-Power-Generator-ALIM2143-.html Shaft system]
 +
# [http://machinedesign.com/article/green-technology-inside-an-advanced-wind-turbine-0605 Gear box]
 +
# [http://www1.eere.energy.gov/windandhydro/wind_how.html Anemometer & Wind vane]
 +
 +
|-
 +
|}
 +
 
=Contact Dolcera=
 
=Contact Dolcera=
  

Latest revision as of 01:54, 27 July 2015

This report presents a brief introduction to wind energy and technologies available for horizontal wind turbines. A detailed taxonomy for horizontal axis wind turbines is presented covering parts of the turbine, control systems, applications among others. A detailed landscape analysis of patent and non-patent literature is done with a focus on Doubly-fed Induction Generators (DFIG) used in the horizontal axis wind turbines for efficient power generation. The product information of major players in the market is also captured for Doubly-fed Induction Generators. The final section of the report covers the existing and future market predictions for wind energy-based power generation.

Process Flow


Introduction

  • We have been using wind power at least since 5000 BC to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. The use of wind to provide mechanical power came later.
  • Harnessing renewable alternative energy is the ideal way to tackle the energy crisis, with due consideration given to environmental pollution, that looms large over the world.
  • Renewable energy is also called "clean energy" or "green power" because it doesn’t pollute the air or the water. Wind energy is one such renewable energy source that harnesses natural wind power.

Read More?

Click on Wind Energy Background to read more about wind energy.

In order to overcome the problems associated with fixed speed wind turbine system and to maximize the wind energy capture, many new wind farms are employing variable speed wind energy conversion systems (WECS) with doubly-fed induction generator (DFIG). It is the most popular and widely used scheme for the wind generators due to its advantages.

For variable-speed systems with limited variable-speed range, e.g. ±30% of synchronous speed, the doubly-fed induction generator(DFIG) can be an interesting solution. This is mainly due to the fact that the power electronic converter only has to handle a fraction (20-30%) of the total power as the converters are connected to the rotor and not to the stator. Therefore, the losses in the power electronic converter can be reduced, compared to a system where the converter has to handle the total power. The overall structure of wind power generation through DFIG as shown in the figure below.

Market Research

The History of Wind Energy

To read about the History of Wind Energy, click here

Global Wind Energy Market

Market Overview

  • In the year 2010, the wind capacity reached worldwide 196’630 Megawatt, after 159’050 MW in 2009, 120’903 MW in 2008, and 93’930 MW in 2007.
Source: World Wind Energy Report, 2010
  • Wind power showed a growth rate of 23.6 %, the lowest growth since 2004 and the second lowest growth of the past decade.
  • For the first time in more than two decades, the market for new wind turbines was smaller than in the previous year and reached an overall size of 37’642 MW, after 38'312 MW in 2009.
Source: World Wind Energy Report, 2010
  • All wind turbines installed by the end of 2010 worldwide can generate 430 Tera watt hours per annum, more than the total electricity demand of the United Kingdom, the sixth largest economy of the world, and equaling 2.5 % of the global electricity consumption.
  • In the year 2010, altogether 83 countries, one more than in 2009, used wind energy for electricity generation. 52 countries increased their total installed capacity, after 49 in the previous year.
  • The turnover of the wind sector worldwide reached 40 billion Euros (55 billion US$) in 2010, after 50 billion Euros (70 billion US$) in the year 2009. The decrease is due to lower prices for wind turbines and a shift towards China.
  • China became number one in total installed capacity and the center of the international wind industry, and added 18’928 Megawatt within one year, accounting for more than 50 % of the world market for new wind turbines.
  • The wind sector in 2010 employed 670’000 persons worldwide.
  • Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.
  • WWEA sees a global capacity of 600’000 Megawatt as possible by the year 2015 and more than 1’500’000 Megawatt by the year 2020.

Source: World Wind Energy Report, 2010

Global Market Forecast

  • Global Wind Energy Outlook 2010, provides forecast under three different scenarios - Reference, Moderate and Advanced.
  • The Global Cumulative Wind Power Capacity is estimated to reach 572,733 MW by the year 2030, under the Reference Scenario
  • The Global Cumulative Wind Power Capacity is estimated to reach 1,777,550 MW by the year 2030, under the Moderate Scenario
  • The Global Cumulative Wind Power Capacity is estimated to reach 2,341,984 MW by the year 2030, under the Advanced Scenario
  • The following chart shows the Global Cumulative Wind Power Capacity Forecast,under the different scenarios:
Global Cumulative Wind Power Capacity Forecast, Source: Global Wind Energy Outlook 2010


Source: Global Wind Energy Outlook 2010

Market Growth Rates

  • The growth rate is the relation between the new installed wind power capacity and the installed capacity of the previous year.
  • With 23.6 %, the year 2010 showed the second lowest growth rate of the last decade.
World Market Growth Rates, Source: World Wind Energy Report, 2010
  • Before 2010, the annual growth rate had continued to increase since the year 2004, peaking in 2009 at 31.7%, the highest rate since 2001.
  • The highest growth rates of the year 2010 by country can be found in Romania, which increased its capacity by 40 times.
  • The second country with a growth rate of more than 100 % was Bulgaria (112%).
  • In the year 2009, four major wind markets had more than doubled their wind capacity: China, Mexico, Turkey, and Morocco.
  • Next to China, strong growth could be found mainly in Eastern European and South Eastern European countries: Romania, Bulgaria, Turkey, Lithuania, Poland, Hungary, Croatia and Cyprus, and Belgium.
  • Africa (with the exception of Egypt and Morocco) and Latin America (with the exception of Brazil), are again lagging behind the rest of the world in the commercial use of wind power.
  • The Top 10 countries by Growth Rate are shown in the figure listed below (only markets bigger than 200 MW have been considered):
Top Countries by Market Growth Rates, Source: World Wind Energy Report, 2010

Geographical Market Distribution

  • China became number one in total installed capacity and the center of the international wind industry, and added 18'928 Megawatt within one year, accounting for more than 50 % of the world market for new wind turbines.
  • Major decrease in new installations can be observed in North America and the USA lost its number one position in total capacity to China.
  • Many Western European countries are showing stagnation, whereas there is strong growth in a number of Eastern European countries.
  • Germany keeps its number one position in Europe with 27'215 Megawatt, followed by Spain with 20'676 Megawatt.
  • The highest shares of wind power can be found in three European countries: Denmark (21.0%), Portugal (18.0 %) and Spain (16.0%).
  • Asia accounted for the largest share of new installations (54.6%), followed by Europe (27.0%) and North America (16.7 %).
  • Latin America (1.2%) and Africa (0.4%) still played only a marginal role in new installations.
  • Africa: North Africa represents still lion share of installed capacity, wind energy plays hardly a role yet in Sub-Sahara Africa.
  • Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.

Source: World Wind Energy Report, 2010

The regional breakdowns for the period 2009-2030 has been provided for the following three scenarios:

  1. Regional Breakdown: Reference scenario (GWEO 2010)
  2. Regional Breakdown: Moderate scenario (GWEO 2010)
  3. Regional Breakdown: Advanced scenario (GWEO 2010)

Note: To know more about the Forecast Scenarios click here

Country-wise Market Distribution

  • In 2010, the Chinese wind market represented more than half of the world market for new wind turbines adding 18.9 GW, which equals a market share of 50.3%.
  • A sharp decrease in new capacity happened in the USA whose share in new wind turbines fell down to 14.9% (5.6 GW), after 25.9% or 9.9 GW in

the year 2009.

  • Nine further countries could be seen as major markets, with turbine sales in a range between 0.5 and 1.5 GW: Germany, Spain, India, United

Kingdom, France, Italy, Canada, Sweden and the Eastern European newcomer Romania.

  • Further, 12 markets for new turbines had a medium size between 100 and 500 MW: Turkey, Poland, Portugal, Belgium, Brazil, Denmark, Japan, Bulgaria, Greece, Egypt, Ireland, and Mexico.
  • By end of 2010, 20 countries had installations of more than 1 000 MW, compared with 17 countries by end of 2009 and 11 countries byend of 2005.
  • Worldwide, 39 countries had wind farms with a capacity of 100 Megawatt or more installed, compared with 35 countries one year ago, and 24 countries five years ago.
  • The top five countries (USA, China, Germany, Spain and India) represented 74.2% of the worldwide wind capacity, significantly more than 72.9 % in the year.
  • The USA and China together represented 43.2% of the global wind capacity (up from 38.4 % in 2009).
  • The newcomer on the list of countries using wind power commercially is a Mediterranean country, Cyprus, which for the first time installed a larger grid-connected wind farm, with 82 MW.

Source: World Wind Energy Report, 2010

The top 10 countries by Total Installed Capacity for the year 2010, is illustrated in the chart below:

Top Countries by Market Growth Rates, Source: World Wind Energy Report, 2010

To view the Top 10 countries by different other parameters for the year 2010, click on the links below:

  1. Top 10 countries by Total New Installed Capacity
  2. Top 10 countries by Capacity per Capita (kW/cap)
  3. Top 10 countries by Capacity per Land Area (kW/sq. km)
  4. Top 10 countries by Capacity per GDP (kW/ million USD)

To view the Country-wise Installed Wind Power Capacity (MW) 2002-2010 (Source: World Wind Energy Association), click here

Country Profiles

China


Wind Energy Outlook for China - 2011 & Beyond
Despite its rapid and seemingly unhampered expansion, the Chinese wind power sector continues to face significant challenges, including issues surrounding grid access and integration, reliability of turbines and a coherent strategy for developing China’s offshore wind resource. These issues will be prominent during discussions around the twelfth Five-Year Plan, which will be passed in March 2011. According to the draft plan, this is expected to reflect the Chinese government’s continuous and reinforced commitment to wind power development, with national wind energy targets of 90 GW for 2015 and 200 GW for 2020.

For a detailed country profile of China please visit this China Wind Energy Profile Link

India


Wind Energy Main market developments in 2010
Today the Indian market is emerging as one of the major manufacturing hubs for wind turbines in Asia. Currently, seventeen manufacturers have an annual production capacity of 7,500 MW. According to the WISE, the annual wind turbine manufacturing capacity in India is likely to exceed 17,000 MW by 2013.
The Indian market is expanding with the leading wind companies like Suzlon, Vestas, Enercon, RRB Energy and GE now being joined by new entrants like Gamesa, Siemens, and WinWinD, all vying for a greater market share. Suzlon, however, is still the market leader with a market share of over 50%.
The Indian wind industry has not been significantly affected by the financial and economic crises. Even in the face of a global slowdown, the Indian annual wind power market has grown by almost 68%. However, it needs to be pointed out that the strong growth in 2010 might have been stimulated by developers taking advantage of the accelerated depreciation before this option is phased out.

For a detailed country profile of India please visit this India Wind Energy Profile Link

Market Share Analysis

Global Market Share

  • Vestas leads the Global Market in the 2010 with a 12% market share according to Make Consulting, while BTM Consulting reports it to have a 14.8% market share.
  • According to Make Consulting, the global market share of Vestas has decreased from 19% in 2008, to 14.5% in 2009, to 12% in 2010.
  • According to BTM Consulting, the global market share of Vestas has changed from 19% in 2008, to 12% in 2009, to 14.8% in 2010.
  • According to Make Consulting, the global market share of GE Energy has decreased from 18% in 2008, to 12.5% in 2009, to 10% in 2010.
  • The market share of world no. 2 Sinovel, has been constantly increasing, from 5% in 2008 , to 9.3% in 2009, to 11% in 2010
  • The top 5 companies have been occupying more than half of the Global Market Share from 2008 to 2010

Source: Make Consulting, BTM Global Consulting

The chart given below illustrates the Global Market Share Comparison of Major Wind Energy Companies for the period 2008-2010, as provided by two different agencies, Make Consulting and BTM Consulting:

Global Market Share Comparison of Major Companies for the period 2008-2010 , Source: Make Consulting, BTM Global Consulting

Market Share - Top 10 Markets

  • While Vestas is the Global Leader, it is the leader in only one of Top 10 markets, which is 10th placed Sweden
  • But, Vestas is ranked 2nd in 5 of Top 10 markets
  • Sinovel, ranked 2nd globally, features only once in the Top 3 Companies list in the Top 10 markets, but scores globally because it leads the largest market China
  • The table given below illustrates the Top 3 players in Top 10 Wind Energy Markets of the world:
Market MW No. 1 No. 2 No. 3
China 18928 Sinovel Goldwind Dongfang
USA 5115 GE Energy Vestas Siemens
India 2139 Suzlon Enercon Vestas
Germany 1551 Enercon Vestas Suzlon
UK 1522 Siemens Vestas Gamesa
Spain 1516 Gamesa Vestas GE Energy
France 1186 Enercon Suzlon Vestas
Italy 948 Gamesa Vestas Suzlon
Canada 690 Siemens GE Energy Enercon
Sweeden 604 Vestas Enercon Siemens
Source: BTM Consult - part of Navigant Consulting - March 2011

Source: BTM Consult

Company Profiles

  1. Vestas Wind Systems A/S
  2. Suzlon Energy

Major Wind Turbine Suppliers

Turbine maker Rotor blades Gear boxes Generators Towers Controllers
Vestas Vestas, LM Bosch Rexroth, Hansen, Wingery, Moventas Weier, Elin, ABB, LeroySomer Vestas, NEG, DMI Cotas (Vestas),
NEG (Dancontrol)
GE energy LM, Tecsis Wingery, Bosch, Rexroth, Eickhoff, GE Loher, GE DMI, Omnical, SIAG GE
Gamesa Gamesa, LM Echesa (Gamesa), Winergy, Hansen Indar (Gamesa), Cantarey Gamesa Ingelectric (Gamesa)
Enercon Enercon Direct drive Enercon KGW, SAM Enercon
Siemens
wind 		Siemens, LM Winergy ABB Roug, KGW Siemens, KK Electronic
Suzlon Suzlon Hansen, Winergy Suzlon,
Siemens 		Suzlon Suzlon, Mita Teknik
Repower LM Winergy, Renk, Eickhoff N/A N/A Mita Teknik, ReGuard
Nordex Nordex Winergy, Eickhoff, Maag Loher Nordex, Omnical Nordex, Mita Teknik
Source: BTM Consult

Products of Top Companies

S.No. Company Product Specifications
1 Vestas V80 Rated Power: 2.0 MW, Frequency: 50 Hz/60 Hz, Number of Poles: 4-pole, Operating Temperature: -30°C to 40°
2 Vestas V90 Rated Power: 1.8/2.0 MW, Frequency : 50 Hz/60 Hz, Number of Poles : 4-pole(50 Hz)/6-pole(60 Hz), Operating Temperature: -30°C to 40°
3 Vestas V90 Offshore Rated Power: 3.0 MW, Frequency: 50 Hz/60 Hz, Number of Poles: 4-pole, Operating Temperature: -30°C to 40°
4 North Heavy Company 2 MW DFIG Rated Power: 2.0 MW, Rated Voltage: 690V, Rated Current: 1670A, Frequency: 50Hz, Number of Poles : 4-pole, Rotor Rated Voltage: 1840V, Rotor Rated Current 670A, Rated Speed: 1660rpm; Power Speed Range: 520-1950 rpm, Insulation Class: H, Protection Class: IP54, Motor Temperature Rise =<95K
5 Gamesa G90 Rated Voltage: 690 V, Frequency: 50 Hz, Number of Poles: 4, Rotational Speed: 900:1,900 rpm (rated 1,680 rpm) (50Hz); Rated Stator Current: 1,500 A @ 690 V, Protection Class: IP 54, Power Factor(standard): 0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, Power Factor(Optional): 0.95 CAP - 0.95 IND throughout the power range
6 Nordex N80 Rated Power: 2.5 MW, Rated Voltage: 690V, Frequency: 50/60Hz, Cooling Systems: liquid/air
7 Nordex N90 Rated Power: 2.5 MW, Rated Voltage: 690V, Frequency: 50/60Hz, Cooling Systems: liquid/air
8 Nordex N100 Rated Power: 2.4 MW, Rated Voltage: 690V, Frequency: 50/60Hz, Cooling Systems: liquid/air
9 Nordex N117 Rated Power: 2.5 MW, Rated Voltage: 690V, Frequency: 50/60Hz, Cooling Systems: liquid/air
10 Converteam DFIG NA
11 Xian Geoho Energy Technology 1.5MW DFIG Rated Power: 1550KW, Rated Voltage: 690V, Rated Speed: 1755 r/min, Speed Range: 975~1970 r/min, Number of Poles: 4-pole, Stator Rated Voltage: 690V±10%, Stator Rated Current: 1115A; Rotor Rated Voltage: 320V, Rotor Rated Current: 430A, Winding Connection: Y / Y, Power Factor: 0.95(Lead) ~ 0.95Lag, Protection Class: IP54, Insulation Class: H, Work Mode: S1, Installation ModeI: M B3, Cooling Mode: Air cooling, Weight: 6950kg
12 Tecowestinghouse TW450XX (0.5-1 KW) Rated Power: 0.5 -1 KW, Rated Voltage: 460/ 575/ 690 V, Frequency: 50/ 60 Hz, Number of Poles: 4/6, Ambient Temp.(°C): -40 to 50, Speed Range (% of Synch. Speed): 68% to 134%, Power Factor (Leading): -0.90 to +0.90 , Insulation Class: H/F, Efficiency: >= 96%
13 Tecowestinghouse TW500XX (1-2 KW) Rated Power: 1-2 kW, Rated Voltage: 460/ 575/ 690 V, Frequency: 50/ 60 Hz, Number of Poles: 4/6, Ambient Temp.(°C): -40 to 50; Speed Range (% of Synch. Speed): 68 to 134%, Power Factor(Leading): -0.90 to +0.90, Insulation Class: H/F, Efficiency: >= 96%
14 Tecowestinghouse TW560XX (2-3 KW) Rated Power: 2-3kW, Rated Voltage: 460/ 575/ 690 V, Frequency: 50/ 60 Hz, Number of Poles: 4/6, Ambient Temp(°C): -40 to 50, Speed Range(% of Synch. Speed): 68 to 134%, Power Factor(Leading): -0.90 to +0.90, Insulation Class: H/F, Efficiency: >= 96%.
15 Acciona AW1500 Rated Power: 1.5MW, Rated Voltage: 690 V, Frequency: 50 Hz, Number of Poles: 4, Rotational Speed: 900:1,900 rpm(rated 1,680 rpm) (50Hz), Rated Stator Current: 1,500 A @ 690 V, Protection Class: IP54, Power Factor(standard): 0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, Power factor(optional): 0.95 CAP - 0.95 IND throughout the power range
16 Acciona AW3000 Rated Power: 3.0MW, Rated Voltage: 690 V, Frequency: 50 Hz, Number of Poles: 4, Rotational Speed: 900:1,900 rpm(rated 1,680 rpm) (50Hz), Rated Stator Current: 1,500 A @ 690 V, Protection Class: IP54, Power Factor(standard): 0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, Power Factor (optional): 0.95 CAP - 0.95 IND throughout the power range
17 General Electric GE 1.5/2.5MW Rated Power: 1.5/2.5 MW, Frequency(Hz): 50/60

IP Search & Analysis

Doubly-fed Induction Generator: Search Strategy

The present study on the IP activity in the area of horizontal axis wind turbines with focus on Doubly-fed Induction Generator (DFIG) is based on a search conducted on Thomson Innovation.

Control Patents

S. No. Patent/Publication No. Publication Date
(mm/dd/yyyy) 		Assignee/Applicant Title
1 US6278211 08/02/01 Sweo Edwin Brush-less doubly-fed induction machines employing dual cage rotors
2 US6954004 10/11/05 Spellman High Voltage Electron Doubly fed induction machine
3 US7411309 08/12/08 Xantrex Technology Control system for doubly fed induction generator
4 US7485980 02/03/09 Hitachi Power converter for doubly-fed power generator system
5 US7800243 09/21/10 Vestas Wind Systems Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
6 US7830127 11/09/10 Wind to Power System Doubly-controlled asynchronous generator

Patent Classes

S. No. Class No. Class Type Definition
1 F03D9/00 IPC Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)
2 F03D9/00C ECLA Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus) / The apparatus being an electrical generator
3 H02J3/38 IPC Generation, conversion, or distribution of electric power / Circuit arrangements or systems for supplying or distributing electric power; systems for storing electric energy / Circuit arrangements for ac mains or ac distribution networks / Arrangements for parallely feeding a single network by two or more generators, converters or transformers
4 H02K17/42

IPC Generation, conversion, or distribution of electric power / Dynamo-electric machines / Asynchronous induction motors; Asynchronous induction generators / Asynchronous induction generators
5 H02P9/00 IPC Generation, conversion, or distribution of electric power / Control or regulation of electric motors, generators, or dynamo-electric converters; controlling transformers, reactors or choke coils / Arrangements for controlling electric generators for the purpose of obtaining a desired output
6 290/044 USPC Prime-mover dynamo plants / electric control / Fluid-current motors / Wind
7 290/055 USPC Prime-mover dynamo plants / Fluid-current motors / Wind
8 318/727 USPC Electricity: motive power systems / Induction motor systems
9 322/047 USPC Electricity: single generator systems / Generator control / Induction generator

Concept Table

S. No. Concept 1 Concept 2 Concept 3
Doubly Fed Induction Generator
1 doubly fed induction generator
2 double output asynchronous machines
3 dual fed systems
4 dual feed
5 dual output

Thomson Innovation Search

Database: Thomson Innovation
Patent coverage: US EP WO JP DE GB FR CN KR DWPI
Time line: 01/01/1836 to 07/03/2011

S. No. Concept Scope Search String No. of Hits
1 Doubly-fed Induction Generator: Keywords(broad) Claims, Title, and Abstract (((((doubl*3 OR dual*3 OR two) ADJ3 (power*2 OR output*4 OR control*4 OR fed OR feed*3)) NEAR5 (induction OR asynchronous)) NEAR5 (generat*3 OR machine*1 OR dynamo*1)) OR dfig or doig) 873
2 Doubly-fed Induction Generator: Keywords(broad) Full Spec. (((((doubl*3 OR dual*3 OR two) ADJ3 (power*2 OR output*1 OR control*4 OR fed OR feed*3)) NEAR5 (generat*3 OR machine*1 OR dynamo*1))) OR dfig or doig) -
3 Induction Machine: Classes US, IPC, and ECLA Classes ((318/727 OR 322/047) OR (H02K001742)) -
4 Generators: Classes US, IPC, and ECLA Classes ((290/044 OR 290/055) OR (F03D000900C OR H02J000338 OR F03D0009* OR H02P0009*)) -
5 Combined Query - 2 AND 3 109
6 Combined Query - 2 AND 4 768
7 French Keywords Claims, Title, and Abstract ((((doubl*3 OR dual*3 OR two OR deux) NEAR4 (nourris OR feed*3 OR puissance OR sortie*1 OR contrôle*1)) NEAR4 (induction OR asynchron*1) NEAR4 (générateur*1 OR generator*1 OR machine*1 OR dynamo*1)) OR dfig or doig) 262
8 German Keywords Claims, Title, and Abstract (((((doppel*1 OR dual OR two OR zwei) ADJ3 (ausgang OR ausgänge OR kontroll* OR control*4 OR gesteuert OR macht OR feed*1 OR gefüttert OR gespeiste*1)) OR (doppeltgefüttert OR doppeltgespeiste*1)) NEAR4 (((induktion OR asynchronen) NEAR4 (generator*2 OR maschine*1 OR dynamo*1)) OR (induktion?maschinen OR induktion?generatoren OR asynchronmaschine OR asynchrongenerator))) OR dfig) 306
9 Doubly-fed Induction Generator: Keywords(narrow) Full Spec. (((((((doubl*3 OR dual*3) ADJ3 (power*2 OR output*4 OR control*4 OR fed OR feed*3))) NEAR5 (generat*3 OR machine*1 OR dynamo*1))) SAME wind) OR (dfig SAME wind)) 1375
10 Top Assignees - (vestas* OR (gen* ADJ2 electric*) OR ge OR hitachi OR woodward OR repower OR areva OR gamesa OR ingeteam OR nordex OR siemens OR (abb ADJ2 research) OR (american ADJ2 superconductor*) OR (korea ADJ2 electro*) OR (univ* NEAR3 navarra) OR (wind OR technolog*) OR (wind ADJ2 to ADJ2 power)) -
11 Combined Query - 2 AND 10 690
12 Top Inventors - ((Andersen NEAR2 Brian) OR (Engelhardt NEAR2 Stephan) OR (Ichinose NEAR2 Masaya) OR (Jorgensen NEAR2 Allan NEAR2 Holm) OR ((Scholte ADJ2 Wassink) NEAR2 Hartmut) OR (OOHARA NEAR2 Shinya) OR (Rivas NEAR2 Gregorio) OR (Erdman NEAR2 William) OR (Feddersen NEAR2 Lorenz) OR (Fortmann NEAR2 Jens) OR (Garcia NEAR2 Jorge NEAR2 Martinez) OR (Gertmar NEAR2 Lars) OR (KROGH NEAR2 Lars) OR (LETAS NEAR2 Heinz NEAR2 Hermann) OR (Lopez NEAR2 Taberna NEAR2 Jesus) OR (Nielsen NEAR2 John) OR (STOEV NEAR2 Alexander) OR (W?ng NEAR2 Haiqing) OR (Yuan NEAR2 Xiaoming)) -
13 Combined Query - ((3 OR 4) AND 10) 899
14 Final Query - 1 OR 5 OR 6 OR 7 OR 8 OR 9 OR 11 OR 13 2466(1060 INPADOC Families)

Taxonomy

  • Use the mouse(click and drag/scroll up or down/click on nodes) to explore nodes in the detailed taxonomy
  • Click on the red arrow adjacent to the node name to view the content for that particular node in the dashboard

Sample Analysis

A sample of 139 patents from the search is analyzed based on the taxonomy. Provided a link below for sample spread sheet analysis for doubly-fed induction generators.

Patent Analysis

S.No. Patent/Publication No. Publication Date
(mm/dd/yyyy) 		Assignee/Applicant Title Dolcera Analysis
Problem Solution
1 US20100117605 05/13/10 Woodward Method of and apparatus for operating a double-fed asynchronous machine in the event of transient mains voltage changes The short-circuit-like currents in the case of transient mains voltage changes lead to a corresponding air gap torque which loads the drive train and transmission lines can damages or reduces the drive train and power system equipments. The method presents that the stator connecting with the network and the rotor with a converter. The converter is formed to set a reference value of electrical amplitude in the rotor, by which a reference value of the electrical amplitude is set in the rotor after attaining a transient mains voltage change, such that the rotor flux approaches the stator flux.
2 US20100045040 02/25/10 Vestas Wind Systems Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed The DFIG system has poor damping of oscillations within the flux dynamics due to cross coupling between active and reactive currents, which makes the system potentially unstable under certain circumstances and complicates the work of the rotor current controller. These oscillations can damage the drive train mechanisms. A compensation block is arranged, which feeds a compensation control output to the rotor of the generator. The computation unit computes the control output during operation of the turbine to compensate partly for dependencies on a rotor angular speed of locations of poles of a generator transfer function, so that the transfer function is made independent of variations in the speed during operation of the turbine which eliminates the oscillations and increases the efficiency of the wind turbine.
3 US20090267572 10/29/09 Woodward Current limitation for a double-fed asynchronous machine Abnormal currents can damage the windings in the doubly- fed induction generator. Controlling these currents with the subordinate current controllers cannot be an efficient way to extract the maximum amount of active power. The method involves delivering or receiving of a maximum permissible reference value of an active power during an operation of a double-fed asynchronous machine, where predetermined active power and reactive power reference values are limited to a calculated maximum permissible active and reactive power reference values, and hence ensures reliable regulated effect and reactive power without affecting the power adjustment, the rotor is electrically connected to a pulse-controlled inverter by slip rings with a static frequency changer, and thus a tension with variable amplitude and frequency is imposed in the rotor.
4 US20090008944 01/08/09 Universidad Publica De Navarra Method and system of control of the converter of an electricity generation facility connected to an electricity network in the presence of voltage sags in said network Double-fed asynchronous generators are very sensitive to the faults that may arise in the electricity network, such as voltage sags. During the sag conditions the current which appears in said converter may reach very high values, and may even destroy it. During the event of a voltage sag occurring, the converter imposes a new set point current which is the result of adding to the previous set point current a new term, called demagnetizing current, It is proportional to a value of free flow of a generator stator. A difference between a value of a magnetic flow in the stator of the generator and a value of a stator flow associated to a direct component of a stator voltage is estimated. A value of a preset calculated difference is multiplied by a factor for producing the demagnetizing current.
5 US7355295 04/08/08 Ingeteam Energy Variable speed wind turbine having an exciter machine and a power converter not connected to the grid a) The active switching of the semiconductors of the grid side converter injects undesirable high frequency harmonics to the grid.
b) The use of power electronic converters (4) connected to the grid (9) causes harmonic distortion of the network voltage. 		Providing the way that power is only delivered to the grid through the stator of the doubly fed induction generator, avoiding undesired harmonic distortion.
Grid Flux Orientation (GFO) is used to accurately control the power injected to the grid. An advantage of this control system is that it does not depend on machine parameters, which may vary significantly, and theoretical machine models, avoiding the use of additional adjusting loops and achieving a better power quality fed into the utility grid.
6 US20080203978 08/28/08 Semikron Frequency converter for a double-fed asynchronous generator with variable power output and method for its operation Optislip circuit with a resistor is used when speed is above synchronous speed, results in heating the resistor and thus the generator leads to limitation of operation in super synchronous range which results in tower fluctuations. Providing a back-to-back converter which contains the inverter circuit has direct current (DC) inputs, DC outputs, and a rotor-rectifier connected to a rotor of a dual feed asynchronous generator. A mains inverter is connected to a power grid, and an intermediate circuit connects one of the DC inputs with the DC outputs. The intermediate circuit has a semiconductor switch between the DC outputs, an intermediate circuit condenser between the DC inputs, and a diode provided between the semiconductor switch and the condenser. Thus the system is allowed for any speed of wind and reduces the tower fluctuations.
7 US20070210651 09/13/07 Hitachi Power converter for doubly-fed power generator system During the ground faults, excess currents is induced in the secondary windings and flows into power converter connected to secondary side and may damage the power converter. Conventional methods of increasing the capacity of the power converter increases system cost, degrade the system and takes time to activate the system to supply power again. The generator provided with a excitation power converter connected to secondary windings of a doubly-fed generator via impedance e.g. reactor, and a diode rectifier connected in parallel to the second windings of the doubly-fed generator via another impedance. A direct current link of the rectifier is connected in parallel to a DC link of the converter. A controller outputs an on-command to a power semiconductor switching element of the converter if a value of current flowing in the power semiconductor switching element is a predetermined value or larger.
8 US20070132248 06/14/07 General Electric System and method of operating double fed induction generators Wind turbines with double fed induction generators are sensitive to grid faults. Conventional methods are not effective to reduce the shaft stress during grid faults and slow response and using dynamic voltage restorer (DVR) is cost expensive. The protection system has a controlled impedance device. Impedance device has bidirectional semiconductors such triac, assembly of thyristors or anti-parallel thyristors. Each of the controlled impedance devices is coupled between a respective phase of a stator winding of a double fed induction generator and a respective phase of a grid side converter. The protection system also includes a controller configured for coupling and decoupling impedance in one or more of the controlled impedance devices in response to changes in utility grid voltage and a utility grid current. High impedance is offered to the grid during network faults to isolate the dual fed wind turbine generator.
9 US20060192390 08/31/06 Gamesa Innovation Control and protection of a doubly-fed induction generator system A short-circuit in the grid causes the generator to feed high stator-currents into the short-circuit and the rotor-currents increase very rapidly which cause damage to the power-electronic components of the converter connecting the rotor windings with the rotor-inverter. The converter is provided with a clamping unit which is triggered from a non-operation state to an operation state, during detection of over-current in the rotor windings. The clamping unit comprises passive voltage-dependent resistor element for providing a clamping voltage over the rotor windings when the clamping unit is triggered.
10 US20050189896 09/01/05 ABB Research Method for controlling doubly-fed machine Controlling the double fed machines on the basis of inverter control to implement the targets set for the machine, this model is extremely complicated and includes numerous parameters that are often to be determined. A method is provided to use a standard scalar-controlled frequency converter for machine control. A frequency reference for the inverter with a control circuit, and reactive power reference are set for the machine. A rotor current compensation reference is set based on reactive power reference and reactive power. A scalar-controlled inverter is controlled for producing voltage for the rotor of the machine, based on the set frequency reference and rotor current compensation reference.

Click here to view the detailed analysis sheet for doubly-fed induction generators patent analysis.

Article Analysis

S.No. Title Publication Date
(mm/dd/yyyy) 		Journal/Conference Dolcera Summary
1 Study on the Control of DFIG and its Responses to Grid Disturbances 01/01/06 Power Engineering Society General Meeting, 2006. IEEE Presented dynamic model of the DFIG, including mechanical model, generator model, and PWM voltage source converters. Vector control strategies adapted for both the RSC and GSC to control speed and reactive power independently. Control designing methods, such as pole-placement method and the internal model control are used. MATLAB/Simulink is used for simulation.
2 Application of Matrix Converter for Variable Speed Wind Turbine Driving an Doubly Fed Induction Generator 05/23/06 Power Electronics, Electrical Drives, Automation and Motion, 2006. SPEEDAM 2006. A matrix converter is replaced with back to back converter in a variable speed wind turbine using doubly fed induction generator. Stable operation is achieved by stator flux oriented control technique and the system operated in both sub and super synchronous modes, achieved good results.
3 Optimal Power Control Strategy of Maximizing Wind Energy Tracking and Conversion for VSCF Doubly Fed Induction Generator System 08/14/06 Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International Proposed a new optimal control strategy of maximum wind power extraction strategies and testified by simulation. The control algorithm also used to minimize the losses in the generator. The dual passage excitation control strategy is applied to decouple the active and reactive powers. With this control system, the simulation results show the good robustness and high generator efficiency is achieved.
4 A Torque Tracking Control algorithm for Doubly–fed Induction Generator 01/01/08 Journal of Electrical Engineering Proposed a torque tracking control algorithm for Doubly fed induction generator using PI controllers. It is achieved by controlling the rotor currents and using a stator voltage vector reference frame.
5 Fault Ride Through Capability Improvement Of Wind Farms Using Doubly Fed Induction Generator 09/04/08 Universities Power Engineering Conference, 2008. UPEC 2008. 43rd International An active diode bridge crowbar switch presented to improve fault ride through capability of DIFG. Showed different parameters related to crowbar such a crowbar resistance, power loss, temperature and time delay for deactivation during fault.

Click here to view the detailed analysis sheet for doubly-fed induction generators article analysis.

Top Cited Patents

S. No. Patent/Publication No. Publication Date
(mm/dd/yyyy) 		Assignee/Applicant Title Citation Count
1 US5289041 02/22/94 US Windpower Speed control system for a variable speed wind turbine 80
2 US4982147 01/01/91 Oregon State Power factor motor control system 62
3 US5028804 07/02/91 Oregon State Brushless doubly-fed generator control system 51
4 US5239251 08/24/93 Oregon State Brushless doubly-fed motor control system 49
5 US6856038 02/15/05 Vestas Wind Systems Variable speed wind turbine having a matrix converter 43
6 WO1999029034 06/10/99 Asea Brown A method and a system for speed control of a rotating electrical machine with flux composed of two quantities 36
7 WO1999019963 04/22/99 Asea Brown Rotating electric machine 36
8 US7015595 03/21/06 Vestas Wind Systems Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch control 34
9 US4763058 08/09/88 Siemens Method and apparatus for determining the flux angle of rotating field machine or for position-oriented operation of the machine 32
10 US7095131 08/22/06 General Electric Variable speed wind turbine generator 25

Top Cited Articles

S. No. Title Publication Date Journal/Conference Citations Count
1 Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation May. 1996 IEEE Proceedings Electric Power Applications 906
2 Doubly fed induction generator systems for wind turbines May. 2002 IEEE Industry Applications Magazine 508
3 Dynamic modeling of doubly fed induction generator wind turbines May. 2003 IEEE Transactions on Power Systems 274
4 Modeling and control of a wind turbine driven doubly fed induction generator Jun. 2003 IEEE Transactions on Energy Conversion 271
5 Ride through of wind turbines with doubly-fed induction generator during a voltage dip Jun. 2005 IEEE Transactions on Energy Conversion 246
6 Dynamic modeling of a wind turbine with doubly fed induction generator July. 2001 IEEE Power Engineering Society Summer Meeting, 2001 196
7 Modeling of the wind turbine with a doubly fed induction generator for grid integration studies Mar. 2006 IEEE Transactions on Energy Conversion 174
8 A doubly fed induction generator using back-to-back PWM converters supplying an isolated load from a variable speed wind turbine Sept. 1996 IEEE Proceedings Electric Power Applications 150
9 Doubly fed induction generator model for transient stability analysis Jun. 2005 IEEE Transactions on Energy Conversion 106
10 Control of a doubly fed induction generator in a wind turbine during grid fault ride-through Sept. 2006 IEEE Transactions on Energy Conversion 112

White Space Analysis

  • White-space analysis provides the technology growth and gaps in the technology where further R&D can be done to gain competitive edge and to carry out incremental innovation.
  • Dolcera provides White Space Analysis in different dimensions. Based on Product, Market, Method of Use, Capabilities or Application or Business Area and defines the exact categories within the dimension.
  • Below table shows a sample representation of white space analysis for controlling DFIG parameters with converters, based on the sample analysis.
White Space of converters used to control
Active power
Reactive Power
Decoupled P-Q control
Field oriented control
Direct torque control
Speed control
Frequency Control
Pitch control
PWM Technique
Low voltage ride through
Network fault/Grid fault
Symmetrical and Asymmetrical Faults
Temp control
Grid Side active converters
 US20070052394A1

US20060028025A1

US20100148508A1

US20100133816A1 EP2166226A1 US20070132248A1 US20070052394A1 US20100096853A1

US20100114388A1 US20090008938A1 WO2010079234A1

US20090230689A1 US20090206606A1 US20070024247A1

US20090206606A1

US20080129050A1

US20100156192A1

US20070182383A1

US20100002475A1

US20080296898A1 US20070273155A1 US20070278797A1

US20070052244A1

US20070024059A1 US20060238929A1

US20070177314A1 EP2166226A1

US20090121483A1 US20090008938A1

Grid side passive converters
 US20030151259A1 US20030151259A1 US20030151259A1
Rotor side converter
 US20100142237A1

US20070052394A1 US20060028025A1

US20100096853A1

US20100148508A1 US20100133816A1 US20070132248A1 US20070052394A1

US20100114388A1 US20090008938A1 WO2010079234A1

US20090230689A1 US20070024247A1

US20080129050A1 US20070182383A1 US20100002475A1

US20080296898A1 US20070273155A1 US20070278797A1

US20080157533A1

US20070052244A1 US20070024059A1 US20060238929A1

US20090273185A1

US20070177314A1

US20090121483A1

US20090008938A1

Matrix converters
 US20020079706A1 US20070216164A1 US20090265040A1 US20070216164A1

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Key Findings

Major Players

Major Players

Key Patents

Key Patents

IP Activity

  • Patenting activity has seen a very high growth rate in the last two years.
Year wise IP Activity

Geographical Activity

  • USA, China, Germany, Spain, and India are very active in wind energy research.
Geographical Activity

Research Trend

  • Around 86% patents are on controlling the doubly-fed induction generation(DFIG) which indicates high research activity going on in rating and controlling of the DFIG systems.

Issues in the Technology

  • 86% of the patent on DFIG operation are focusing on grid connected mode of operation, suggesting continuous operation of the DFIG system during weak and storm winds, grid voltage sags, and grid faults are major issues in the current scenario.
Problem Solution Mapping

Emerging Player

  • Woodward is a new and fast developing player in the field of DFIG technology. The company filed 10 patent applications in the field in year 2010, while it has no prior IP activity.

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References

Background References
  1. Wind Energy History
  2. Wind Energy
  3. Wind Energy Basics
  4. How Wind Turbines Work
  5. Different types of wind turbines
  6. Onshore Vs Offshore Wind Turbines
  7. Wind Power
  8. Types of Wind Farms
  9. Offshore Technology
  10. The Fundamentals of Wind Energy
  11. Winder Tower
  12. Wind Towers
  13. Wind Turbine Blades
  14. Wind Turbine Design Styles
  15. Rotor Hub Assembly
  16. Gearbox for Wind Turbines
  17. The Wind Turbine Yaw Mechanism
  18. The Wind Turbine Yaw Mechanism
  19. Wind Turbine Generators
  20. Inside wind turbines
 Image References
  1. DFIG Working Principle
  2. Country share of total capacity
  3. Wind turbine principle
  4. Horizontal axis wind turbine
  5. Vertical axis wind turbine
  6. Pitch control
  7. Yaw control
  8. Onshore Wind turbines
  9. Offshore wind turbines
  10. Wind turbine parts
  11. Tower height Vs Power output
  12. Tubular tower
  13. Lattice tower
  14. Guy tower
  15. Tiltup tower
  16. Free stand tower
  17. Single blade turbine
  18. Two blade turbine
  19. Three blade turbine
  20. Internal nacelle structure
  21. Rotor hub
  22. Shaft system
  23. Gear box
  24. Anemometer & Wind vane

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Samir Raiyani
Email: info@dolcera.com
Phone: +1-650-269-7952
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