Analysis on Control Method VSCF Wind Power System

By analyzing the operation behavior of an A.C. excited variable-speed constant-frequency (VSCF) wind-power generator, the field-oriented vector control technique and and the internal model controller (IMC) are transplanted into the voltage control of DFIG.The IMC were transplanted into the cutting-in control of the doubly-fed induction generator with no-load and a novel cutting-in control strategy was obtained. The strategy can realize cutting-in without accurate parameters of doubly-fed induction generator (DFIG) and the controller can be designed without accurate DFIG model. A dynamic model of variable pitch and variable speed wind turbine was developed. This model can be used simulate wind turbine and design pitch and toque controller. The research work presented in this paper is aimed to reduce pitch actuator fatigue and smooth output power above-rated power operating condition. To cope with the nonlinear characteristics of wind turbine and reduce the pitch actuator fatigue, a new control strategy for variable pitch variable speed wind turbine is proposed. In the proposed method a variable gains PD controller based on fuzzy control theory is used. The simulation results show that the controllers ensure very good robustness and adaptability under modeling uncertainty and external disturbance, and produce good dynamic performance.