Wind Turbine Pitch Control and Load Mitigation Using an Adaptive Approach

We present an application of adaptive output feedback control design to wind turbine collective pitch control and load mitigation. Our main objective is the design of an output feedback controller without wind speed estimation, ensuring that the generator speed tracks the reference trajectory with robustness to uncertain parameters and time-varying disturbances (mainly the uniform wind disturbance across the wind turbine rotor). The wind turbine model CART (controls advanced research turbine) developed by the national renewable energy laboratory (NREL) is used to validate the performance of the proposed adaptive controller using the FAST (fatigue, aerodynamics, structures, and turbulence) code. A comparative study is also conducted between the proposed controller and the most popular methods in practice: gain scheduling PI (GSPI) controls and disturbance accommodating control (DAC) methods. The results show better performance of output feedback controller over the other two methods. Moreover, based on the FAST software and LQR analysis in the reference model selection of adaptive controller, tradeoff can be achieved between control performance and loads mitigation.