Adaptive ℋ∞ control of variable-speed wind turbines with wind speed estimator

This work presents an adaptive nonlinear ℋ_∞ control strategy for variable-speed wind turbines intended to maximize turbine power extraction. The control structure is shown to robustly reject disturbances acting on the system, particularly those introduced by time-varying wind profiles. Remarkably, the controller does not make use of externally sensed wind speed measures, but are obtained from a properly designed estimator. The estimator make use of the knowledge about the plant dynamics to asymptotically track the average component of the wind profile, providing a reliable measure for control purposes. The overall adaptive controller+wind speed estimator is tested on a wind turbine simulator with realistic wind profiles providing satisfactory results.