Load mitigation for a floating wind turbine via generalized h∞ structural control

Active structural control is a promising and effective approach to load reduction of floatingwind turbines. This paper investigates use of active structural control to mitigate loads of a floating wind turbine on a barge platform. Different from the existing results, static output feedback is employed as the control law for reducing implementation complexity while a turned mass damper is considered to be installed on the platform instead of in the nacelle. To design active structural controllers, first an input-output linear design model for the wind turbine is identified from time response data, and then an advanced generalizedH∞ method is employed for optimizing the controller gain so as to reduce wave induced loads. Through high-fidelity simulation results of the wind turbine, it is found that the designed active controllers could further reduce the main fatigue load and the generator power error, but the standard H∞ one is not economical and lacks enough reliability. The rationale of the generalized H∞ method in trading off load reduction and controller gain reduction is also discussed.