Vibration reduction strategy for wind turbine based on individual pitch control and torque damping control

This paper presents the vibration reduction strategy of large-size pitch-controlled variable-speed wind turbine based on pitch control and torque control. First, the torque control below the rated operating area and the pitch control above rated operating area are presented, and the control method to reduce the coupling between torque control and pitch control is discussed. Then the vibration mechanism and the modal analysis of the main components (the blade, tower and drive train) of wind turbine are studied. In terms of alleviating the blade flap-wise vibration and drive train torsion vibration, the individual pitch control strategy and torque damping control strategy are proposed to reduce the fluctuations of blade flap-wise load and add damping to the drive train torsion vibration mode. Finally, simulations were conducted using the GH Bladed 1.5-MW wind turbine, and the results show that the proposed vibration reduction strategy can effectively alleviate the blade flap-wise vibration and drive train torsion vibration. Besides, because of the coupling relationship of blade/tower/drive train vibration modes, the proposed strategy can also mitigate the tower fore-aft and side-side vibration. Copyright (c) 2016 John Wiley & Sons, Ltd.