Megawatt Level Wind Turbine Fuzzy Control

Wind turbine is a comprehensive system engineering of high technology which deals with aerodynamics, automatic control, mechanical drive and generator etc. The research difficulties and hot pots of wind power are focused on high power capacity, advanced control and optimization etc. Control is crucial to the efficiency and reliability of wind turbines. Wind energy has lower density, instability and randomness, wind turbines have strong nonlinear multivariable with many uncertain factors and disturbances. The thesis expands its investigation on relevant control problems of wind turbines, main contents can be concluded the following:(1) The mathematical model of large-scale wind turbine is established by the method of analysis modeling to reveal the dynamic behavior of complete wind turbine. The model can reflect the basic dynamics and is suitable for control purpose. It also can be used for the validity of control strategy.(2) A new method for estimating the optimal rotating speed at low wind speed is proposed by an application of fuzzy inference system. The method can realize maximum wind energy capture and avoids the inaccuracy by measuring the wind speed. It need not know the aerodynamic characteristics of wind turbine.(3) Adaptive optimal fuzzy system for speed control is proposed based on the motion equation of wind turbine and generator. This algorithm synthesizes the mechanical and electrical characteristics. System identification is part of the controller. An improved nearest-neighbor clustering learning algorithm is proposed for adaptive optimal fuzzy system on the basis of principle introduction. It considers input and output data to determine cluster and adapts the decay factor according to cluster sample amounts. The improved algorithm overcomes the shortcomings of many sensitive parameters and difficult adjustment of parameters.(4) In view of the control request at high wind speed for variable speed constant frequency wind turbine, has designed the fuzzy controller. This controller adjust the pitch angle according to the change of wind speed to limit the energy which the rotor catches and keep rated output power. The simulation result express that the pitch controller has good abilities of real time and robustness.