Wind Turbine Linear Parameter Varying Control Using Fast Code

Linear parameter varying (LPV) control of a three-bladed horizontal-axis wind turbine in partial and full load conditions using FAST code is presented. The multivariable LPV controller is designed for a lumped model of the wind turbine with five degrees-of-freedom consisting blades, drive-train and the tower. The controller is scheduled in real-time based on the mean wind speed. The objective is to minimize the H_∞ performance index from the wind turbulence to the controlled output vector. The closed-loop responses of the LPV controller are compared with a traditional PI-scheduled controller in the FAST/Simulink environment for the NREL 5MW baseline wind turbine. Compared to the PI-scheduled controller, the LPV design reduced the transient loads in switching between partial to full load regions of the operation. The fluctuations of the generator speed and torque are decreased resulting in a smoother power generation. The wind turbine structural loads in terms of blade root flap-wise bending moments and tower fore-aft bending moment are mitigated in different loading conditions.