Moving horizon h∞ control of variable speed wind turbines with actuator saturation

This study suggests a moving horizon ℋ_∞ control scheme for variable speed wind turbines above the rated wind speed to maintain the output power at the rated value for variable operating points. A constrained ℋ_∞ control problem is solved at each sampling time with the update of not only the initial condition but also the prediction model based on different operating points. Closed-loop properties inclusive of ℒ₂ disturbance attenuation are discussed in the framework of dissipation theory. The moving horizon ℋ_∞ control considers the non-linear dynamic aspect of the wind turbine, the turbulent nature of the wind and actuator saturations. Analysis and simulation results for WD34 wind turbine show possible improvements on the output electrical power regulation performance for variable operating points, while respecting actuator saturation limits.