Region II wind power capture maximization using robust control and estimation with alternating gradient search

A two-fold control method is proposed consisting of a nonlinear robust controller working in conjunction with an extremum seeking gradient search controller. The robust controller provides stable control of the rotor angular velocity while also producing an estimation of the hard to measure and nonlinear aerodynamic torque provided by the wind. The gradient search method uses the estimate to update the tipspeed ratio and blade pitch which will drive the system in the direction of increasing turbine power capture. The efficacy of the control method is demonstrated through simulation in the presence of a realistic wind signal and measurement noise in the wind velocity feedback.