Research On Fuzzy Control Of Large-scale Wind Turbine

Energy and environment are pressing problems that must be settled by human beings for future survival and development. Wind energy is one kind of renewable energy, which is cleanliness and free pollution with rich reservation. Wind power generation is the most important form of utilizing wind energy. Developing wind power generation to adjust the energy structure and improve environment is an important strategy in the energy development domain, has been highly regarded by various countries' government.Wind energy has lower density, instability and randomicity, wind turbines have strong nonlinear multivariable with many uncertain factors and disturbances, the exact model is uneasy established, so Conventional PID control method is difficult to obtain satisfactory control effect. The fuzzy control is a kind of effective control strategy to implement to the object which is difficult to establish precise mathematical model. This paper studies the fuzzy control theory application to large-scale variable speed-variable pitch wind turbine. Main works can be concluded the following:It adopts the mechanism analytic method to obtain each part of wind turbine's submodel, including wind speed, wind rotor, drive system, generator, then the entire unit's model is realized in the Simulink environment of MATLAB software.Based on introduction the basic principle of fuzzy control and fuzzy controller's design and classification, one kind of simplified PID type fuzzy controller is deduced. This fuzzy controller only needs two input variables and one rule base, which reduces control rule greatly. In order to validate the performance of simplified PID type fuzzy controller, it is compared with the PD and PI type fuzzy controller. The simulation result indicates that the performance of the PID fuzzy controller is preferable to the PD and PI type fuzzy controller when choosing the same controller parameters.Power coefficient of wind turbine is a nonlinear function of blade pitch angle and tip speed ratio. Neural network model for power coefficient is proposed, this model can fit the power coefficient well. The simplified PID type fuzzy controller is applied to the variable speed control and variable pitch control of the variable speed-variable pitch wind turbine. Below the rated wind speed, through adjustment asynchronous generator's stator voltage to control the wind rotor speed, and realize capture more wind energy. Above the rated wind speed, we change the power coefficient through the adjustment blade pitch angle to realize output power nearby the rated power. Finally, this fuzzy control method is compared with the PID controller, the simulation result indicates that the fuzzy control method is preferable to the PID controller.