Pitch varying control method and system of wind turbine generator

The invention discloses a pitch varying control method and system of a wind turbine generator. The method includes the steps that current rotating speed of a wind wheel is acquired; the difference between the current rotating speed and a reference rotating speed of the wind wheel is calculated; according to the formulae shown in the specification, the angle needed by pitch varying is calculated; the wind turbine generator is controlled to execute pitch varying motions corresponding to the angle needed by pitch varying. By the adoption of the pitch varying control method and system of the wind turbine generator, super adjustment generated by the angle needed by pitch varying can be reduced, and following features of the pitch varying motions on wind speed changes can be enhanced.