Study for Comprehensive Regulation of the Frequency Characteristics of Doubly-Fed Variable Speed Wind Turbine

Doubly fed induction generator use a back-to-back dual PWM converters that it can decouple of active power and reactive power, leading to reduce the system's frequency response. If it does not take additional control strategy, when the wind turbine capacity increases to a certain extent, frequency stability of the grid will have a significant hazard. On the one hand, when the frequency control loop responding the diversification of the system frequency is installed in the rotor of the doubly-fed variable speed wind turbines, the frequency can be regulated by controlling the rotor's kinetic energy. On the other hand, by additional frequency control loop is installed in pitch angle control system, the wind turbine can also contribute to frequency control. In this paper by synthesizing the above two methods, wind farms can be participate in a better performance in frequency regulation. The results of the simulation show that the above-mentioned method is correct.