Study On Fuzzy Control For Variable-Speed Variable Pitch Doubly-Fed Wind Turbine

Human economic and social development are inseparable from energy supply. Reserves of conventional energy is not only limited, but large-scale use can also cause environment pollution. In order to solve the problem of contradiction between population and environment, we should establish new energy strategy and develop recycling economy. As an inexhaustible and renewable energy, wind energy has been paid more and more attention by countries and regions. Meanwhile, advanced and reliable control technology is an important guarantee for the popularization and promotion of wind power. At present, Double-fed variable speed wind turbine is the mainstream model of wind turbine. The research on variable pitch control and maximum power point tracking based on double-fed wind generator had been paid more and more attentions.This article first analyses the characteristic of wind electric power system, and a proximate mathematical model for variable pitch system is provided by identifying the model with the spot Data, then the simulation model of wind electric power system is built. In order to achieve a rapid control for the output power, a 3-stage phase control scheme is proposed,in which the deviation between desired output power and actual output power is used for control decision. Min-max pitch angle control, fuzzy control and integrator compensating control is used in different stage to guarantee the fast and errorness adjusting of output power. Fuzzy control system of which wind speed and generator power are considered as control input, and pitch angle of wind turbine is considered as output is designed by ANFIS toolbox. Moreover, simulations under complex wind conditions are given, and the results show that the controller has good dynamic and static characteristics.During the research of maximum power tracking control, we first investigate the principle of tracing maximum wind-energy for doubly-fed wind generator, then the mathematical model for doubly-fed wind generator is simplified by using vector control of stator flux linkage. Taking into account the drawback of power perturbation analysis during the maximum wind-energy process, speed presetting caculation and speed fine tuning fuzzy control is investigated according to the change rate of the speed velocity. A strategy of reactive power, speed PI control and feedback compensating is utilized to improve the control response speed. Finally, simulation results show the effectiveness of the proposed method.