Integrated control strategy for the vibration mitigation of wind turbines based on pitch angle control and TMDI systems

Abstract

Modern wind turbines are becoming taller and more slender to gather wind energy more efficiently and are increasingly installed in complex environments. Consequently, the new generations of wind turbines are prone to vibration-related problems, making the development of vibration control strategies important. Various pitch angle control methods and dynamic vibration absorbers (DVAs) have been proposed recently to reduce the aerodynamic forces and structural responses of wind turbines. However, these approaches are often implemented independently, limiting the effectiveness of the overall control strategy. In this paper, pitch angle control and DVAs are integrated to improve the performance of wind turbines in a complex environment. Firstly, a simplified eight degree-of-freedoms (DOFs) model of the wind turbine is developed using Lagrange’s Equation, and the wind turbine is linearized at specific operating points. The NREL 5MW wind turbine is taken as a benchmark model with strategies based on a proportional–integral (PI) pitch controller. Secondly, the pitch angle of each blade is adjusted by the combination of disturbance accommodating control (DAC) and linear quadratic gaussian (LQG) controller considering the wind speed disturbances. Additionally, the tuned mass damper with inerter (TMDI) is adopted to further suppress the structural vibrations. Thirdly, the passive and active methods of TMDl integrated with the pitch controller are investigated. Lastly, the effectiveness of the integrated control strategies is assessed when the wind turbines are subjected to earthquake and wind loads. The results indicate that combining active pitch control and TMDI can improve the power generation performance of wind turbines by reducing structural responses and damage-equivalent loads, and can also improve the power generation performance more effectively than when they are used separately.