Multiobjetive H2/H control of a pitch regulated wind turbine for mechanical load reduction.

The paper deals with the design of acontrol system for a variable-speed pitch-regulatedwind turbine in the operating region correspond-ing to wind speeds above rated wind speed. Thecontrol objectives are mostly to regulate the plantoutput power and to reduce the mechanical fatigueof the plant components. The controller is designedfrom a non linear model of the system which takesinto account the blades, shaft and tower flexibil-ities. A Linear Matrix Inequalities (LMI) formu-lation of the control problem permits to obtaina Linear Parameter Varying (LPV) controller op-timizing, throughH2/H∞norm minimization, acriteria close to mechanical fatigue affecting theplant. The proposed controller performances arethen compared in simulation with those of a gainscheduling Linear Quadratic Gaussian (LQG) con-troller and with a gain scheduling PI controller, andis seen to be more efficient.