A Robust Controller with Active Tendons for Vibration Mitigation in Wind Turbine Rotor Blades

A new robust active controller design to suppress flapwise vibrations in wind turbine rotor blades is presented in this chapter. The control is based on active tendons mounted inside the blades of a horizontal-axis wind turbine (HAWT). The multimodal model proposed includes the effects of centrifugal stiffening, gravity, and aerodynamic loading. Dynamic interaction between the blades and the tower has been included, and variable mass and stiffness per unit length of the blade have been also taken into account. A robust model predictive control (MPC) algorithm has been implemented to study the effectiveness of the proposed active control system. Due to its high complexity and to the variable nature of its operating environment, a wind turbine is subjected to changes in operating condition. As a consequence, significant variations may occur in certain parameters of the turbine. Therefore, robustness is of particular concern for control design purposes. The main advantage of the proposed method is to explicitly incorporate plant model uncertainty in designing the controller. Numerical simulations have been carried out by using data describing aerodynamic and structural properties for a 5-MW wind turbine.