Pitch control design for optimum energy capture in variable-speed wind turbines

In this paper, we consider the pitch control of variable speed wind turbines with the aim of maximizing power output. Pitch angle control is a common approach for regulating the aerodynamic torque of the wind turbine when wind speed is above rated speed. The proposed pitch controller includes two paths, a nonlinear feed-forward path and a linear feedback path. The feed-forward path uses the information about the desired power output, wind velocity and the turbine speed to determine the pitch angle required. The gains of the linear controller are tuned to minimize changes in the tip speed ratio, which in turn will lead to optimum power. The results obtained from the implementing the proposed controller to a wind turbine show a good performance and optimum energy capture.