Study On Excitation Source Control Policy Of Variable Speed Constant Frequency Double Fed Wind Power Generation System

Nowadays the problems of energy lack and environment pollution are more and more serious, the utilization of renewable energy is popular all over the world. Wind power generation develop rapidly because of its cleanliness and free pollution. Variable speed constant frequency (VSCF) double fed wind power generation is the research hotspot in wind power generation systems. The VSCF double fed wind power generation has many advantages, such as low cost, smaller rating of the excitation converter and very good performance. So it is especially suitable for wind power generation.This paper first has analyzed the characteristics of the wind turbine and the operation principle of the maximum wind energy capture. Then, the structure characteristics and opration principle of doubly fed induction generator (DFIG) have been researched. According to the characteristic of DFIG, the stator flux oriented vector control technique is applied in it's excitation control.With combination of vector control technique, inverse system method and variable structure control technique, a new excitation control strategy is presented for VSCF double fed wind power generation. First, with the inverse system method, the original system model of DFIG is linearized and decoupled to be a pseudo linear system. Then, the variable structure controller is designed for the pseudo linear system. Finally, the system VSCF double fed wind power generation is established under the support of Matlab soft. The simulation by Matlab/simulink proves the proposed no-load cutting-in scheme is relatively ideal and the active power, the reactive power can be decoupled. Compared with PI controller, Variable structure controller shows better dynamic response.