Wind turbine generator, active damping method thereof, and windmill tower

A wind turbine generator comprising a plurality of blades attached to a hub within a nacelle and a mechanism for active damping of the wind turbine generator including a pitch-angle control mechanism for controlling a pitch angle of the blades on the basis of a blade-pitch-angle command, and an accelerometer, attached to a nacelle, for detecting the acceleration due to vibrations of the nacelle, wherein the mechanism comprises:

• a phase compensator which applies phase compensation by a predetermined amount, an integrator coupled to the phase compensator,
• a calculation device which, on the basis of the results of the integration and the phase compensation, calculates a pitch angle of the windmill blades so as to generate a thrust on the windmill blades which tends to cancel out the vibrations on the nacelle, a combiner coupled to the calculation device which produces a blade-pitch-angle command value taking into account the pitch angle calculated by the calculation device and other information,
• a limiter coupled to the calculation device for limiting a pitch angle value or the rate of variation of a pitch angle value,
• a device for providing the blade-pitch-angle command to the pitch angle control mechanism based on the calculated pitch angle.