METHOD AND SYSTEM FOR DETECTION AND MITIGATION OF EDGE-WISE VIBRATIONS IN WIND TURBINE BLADES

A method for detecting and reducing edgewise vibrations in a rotor blade of a wind turbine includes, for a given wind speed, determining a frequency or frequency band at which edgewise vibrations are producible in the rotor blade. The method determines an electrical characteristic of the pitch actuator that correlates to an increased torque required to hold a pitch angle of the rotor blade constant at the frequency or frequency band. During an operational power-production mode of the wind turbine, the electrical characteristic of the pitch actuator is monitored. Upon the electrical characteristic reaching a predefined limit value indicative of edgewise vibrations in the rotor blade, corrective action is initiated by the wind turbine controller to reduce or prevent the edgewise vibrations.