Fan pitch angle control method and device with active power grid supporting function

The invention relates to a fan pitch angle control method and device with an active power grid supporting function. The method comprises the steps of calculating an electromagnetic torque static valueof a generator under a target working condition according to a generator power set value under a target voltage and a target frequency, specifically, the target working condition is the working condition when the generator works in a normal power system state; performing difference between the electromagnetic torque static value of the generator under the target working condition and the electromagnetic torque value of the generator under the current working condition to obtain an electromagnetic torque pre-variable of the generator; and calculating the variable quantity of a pitch angle according to the electromagnetic torque pre-variable of the generator, and controlling a variable-pitch system according to the variable quantity of the pitch angle. By means of a pre-control mode, the pitch angle of a wind wheel