Methods for overcoming unwanted effects by cogging torque in a wind turbine

摘要

Methods for operating a wind turbine, preferably a direct drive wind turbine, comprising a permanent magnet generator (41) driven by a wind rotor (15) that supply power to an electric grid (7) through a power electronics unit (47) that, in an idling situation that create a cogging torque that can stop the wind rotor (15), arrange the frequency converter (49) of said power electronics unit (47) for controlling the current so that an opposing torque to said cogging torque is created allowing a free idling situation. The invention also refers to a control system to carry out said methods and to wind turbine comprising said control system.