Changes

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.