A Control Strategy for Variable-Speed Variable-Pitch Wind Turbines within the regions of partial- and full-load operation without wind speed feedback

摘要

In this paper, the control of a variable-speed variable-pitch wind turbine in the whole wind speed range is addressed, without any feedback measurement of wind speed. An aerodynamic torque observer is adopted to ensure the tracking of the Maximum Delivered Power in the partial-load region, while a novel wind speed observer is proposed for power regulation in the full-load region, along with a novel sliding surface ensuring finite-time set-point stabilization of the speed tracking error. Transitions between regions can be seen as changes in the reference to be tracked by the generator electrical torque and by the blades pitch angle. The proposed control solution has been validated on the National Renewable Energy Laboratory (NREL) 5 - MW three-blade wind turbine model.