Adaptive power acquisition control of variable-speed wind energy conversion systems under inaccurate wind speed measurement

In this paper, a novel nonlinear adaptive torque controller is proposed for variable-speed wind energy conversion systems to track the maximum power curve. Firstly, the controller is designed for the ideal case where known system parameters are assumed. Then, in the presence of uncertain internal system dynamics, the need for the exact knowledge of the system model is waived by using adaptive technologies. Furthermore, the chattering phenomenon in the generator torque which can result in high mechanical stress is avoided by adopting a modified robust term. Compared with existing methods, no accurate measurement of wind speed is required for the controller design. The control goal is achieved in the sense that the tracking error is guaranteed to converge to an arbitrarily small set. It is theoretically proved that all the signals in the closed-loop system are bounded via Lyapunov synthesis. Finally, the effectiveness and the merit of our proposed controller is shown by simulation on a 1.5MW three-blade wind turbine.