Fan variable- pitch optimizing method based on diagonal smooth power control

The invention discloses a fan variable-pitch optimizing method based on diagonal smooth power control. Aiming at solving the problem of frequent pitch changing of a fan under the air condition of highair speed, the method sufficiently uses the large rotational inertia air wheel kinetic energy buffering/release function of any pitch angle and achieves the rotation speed interval control of the fanunder any pitch angle on the basis of reducing the output power fluctuation of the fan based on diagonal smooth power control. Through cooperative use of the variable-speed adjustment and variable-pitch adjustment, the smooth variable-speed adjustment causes power fluctuation due to small-amplitude and high-frequency air speed fluctuation, and the variable-pitch adjustment responds to the large-amplitude and low-frequency air speed changes. The amplitude and frequency of the variable-pitch action are reduced effectively while influence of the power fluctuation on the power grid frequency is not expanded, the fatigue degree and blade loads of a variable-pitch servo mechanism are reduced, and the service life of the fan is prolonged.