Active Vibration Control of Wind Turbine Using Virtual TMD Algorithm Based on Aerodynamic-Structure-Servo Coupling Model

Abstract

In order to extract more wind energy, the wind turbine rotor becomes larger and the tower becomes taller. With more flexibility and smaller damping, wind turbine tower is prone to vibrate in winds. Meanwhile, the tower suffers the periodic loadings caused by the rotor rotation in the operational condition. The excessive vibrations could not only significantly affect the power generation but shorten the structural life due to the fatigue as well. It is challenging to reduce the vibration caused by the rotor rotation using the passive tuned mass damper (TMD) and traditional LQR controller due to the limited effective bandwidth. Therefore, an active tuned mass damper (ATMD) using a virtual TMD algorithm is proposed to mitigate the along-wind vibration of the tower under parked and operational conditions. The virtual TMD algorithm exhibits wide effective bandwidth and only requires the acceleration information on the top of the tower or the relative displacement of the active TMD. Firstly, the aerodynamic-structure-servo coupling (ASSC) model of the wind turbine is established which considers the interaction among the aerodynamic load, structure, and servo system. Secondly, the accuracy of the ASSC model is then verified using the onshore 5 MW wind turbine by the National Renewable Energy Laboratory (NREL). Thirdly, the ATMD feedback control force is designed by the virtual TMD algorithm. Finally, the reduction effect on the along-wind vibration by the proposed controller is evaluated at both of operational and parked conditions using the ASSC model. The TMD and LQR controller are utilized for comparison. The numerical results demonstrate that tuned mass damper (TMD) system with fixed parameters becomes detuned and may loses its effectiveness at different wind speeds. In contrast, active control can suppress the vibration of wind turbines at different wind speeds. Compared to the LQR controller, the proposed controller can enhance the reduction effect of wind turbine response with smaller stroke and control force at operational conditions.