Output power level control of variable-speed variable-pitch wind generators

A robust pitch controller for variable-speed variable-pitch wind generator systems (VSVP-WGS) is presented, in order to level the wind energy conversion based on the perturbation theory and inverse-system method. The robust pitch controller is composed of a nominal inverse-system controller and a robust compensator. With the nominal inverse-system controller, the nominal close loop system can be converted into a pseudo-linear one and then be simply stabilized by linear system approach. With the robust compensator, turbine parameters uncertainties and other nonparametric perturbations, such as the generator torque disturbances and noise, are tolerated. The performance of the robust pitch controller (RPC), which is confirmed through theory analyses and simulations, show that, it can robustly level the output power of the wind generator systems. Compared with other nonlinear controllers, RPC is simpler and can be more easily extended to other kinds of WGS.