A Novel Torsional Vibration Mitigation Strategy for DFIG Based Wind Turbines

During normal operation Doubly Fed Induction Generator (DFIG) wind turbine drivetrains are exposed to transients in mechanical and electromagnetic torque which excite drivetrain torsional modes. This can cause twisting in the drivetrain which over time can weaken the system and eventually result in failure. This paper presents an active damping method to smooth drivetrain transients that may arise due to turbulent winds or faults in the power system. The proposed method utilizes the generator and turbine speeds to maintain the drivetrain twist angle at a stable value and is realized through sliding mode control. The efficacy of the proposed method is verified through subjecting the wind generator to rapid changes in wind speed and power system transients. Simulations are carried out using the detailed DFIG model in the RTDS® simulation platform.