Vibration control of wind turbine towers with the nonlinear tuned liquid damper considering the aero-elastic coupling behavior

Large-megawatts wind turbines with big-scale blade and tower have been rapidly upgraded and developed in the past several years, resulting in the more significant aero-elastic coupling vibrations between operating blade and tower structures. By means of the low design-cost, virtually maintenance-free and simpler frequency-tuning pattern, nonlinear tuned liquid dampers (TLDs) provide a promising means in controlling the vibrations of wind turbine tower. This paper considers the structural aero-elastic coupling behavior of wind turbine to evaluate the vibration control performance of nonlinear TLD synthetically. A dynamical aero-elastic coupling model of wind turbine is established by combining Euler-Lagrange equation with blade element momentum (BEM) method, and this model is validated by using the OpenFAST simulation tool. The stiffness and damping nonlinearities induced by the irregular liquid slope-deformation are considered to design a control system of nonlinear TLD, and the control performances of this nonlinear TLD for wind turbine tower are investigated and evaluated comprehensively. The theoretical and numerical analysis results indicated that the control capability of nonlinear TLD greatly depends on the aerodynamic damping of wind turbine under the different operation conditions, and it can provide the more outstanding contributions in controlling the dynamic responses of tower-top at side-side direction.