The article adopting strategy of fuzzy reasoning,proposed method of control paddle pitch angle of windmill according to propeller pitch control principle of mutative propeller pitch aerogenerator of constant rate constant frequency in order to make it keep specific speed at high wind velocity and obtain steady delivered power.

When the wind speed is above the rated value,pitch angle is regulated to maintain the constant power output and the constant rotor speed.

In the case of the consideration of angle of attack,propeller pitch angle,yawing rotation,gravity and moment of inertia,a mathematical model based on static analysis is put forward,which is used to study loads of the blade bearing system of a wind turbine.

According to the theory of the function approximation,we take the existing characteristic curve of propeller for Fourier analysis,and on this basis,get the empirical formula of the propeller efficiency and the propeller blade angle.