Optimal Output Feedback H_∞ Torque Control of a Wind Turbine Rotor using a Parametrically Scheduled Model

Abstract. Wind turbines are nonlinear, time-varying systems that are subject and sensitive to model parameter variations and a stochastic wind field. For such applications, Linear Parameter Varying (LPV) control provides a state-space approach to designing nonlinear controllers with robust performance. LPV uses multi-input multi-output (MIMO) model with a guaranteed limit on the exogenous disturbance's gain with respect to performance signals. A robust matrix inequality synthesis of an H_∞ based performance LPV controller using a parametrically varying model will be developed with the goal of obtaining a torque controller with drive-train damping properties. The technique guarantees a-priori performance values and closed-loop stability for the simplified model, and provides a systematic tuning procedure to adjust controller performance.