Application of an Augmented Unscented H-infinity Effective Wind Speed Estimation to H-infinity Control of Wind Turbines

Wind energy is a fast-growing industry in Canada and worldwide. As wind turbine size and capacity increase, control systems become exceedingly important in order to maximize the efficiency of the power output and to reduce loads to extend their longevity. Effective wind speed (EWS) is not easy to measure because wind speed varies in time and space across the rotor area of the turbine, nor is it a real physical signal. This research builds on a previous paper’s method of EWS estimation to design a turbine controller based on this normally unknown input. The unscented H-infinity scheme was used in combination with a data fusion technique to estimate effective wind speed. The EWS was used to determine the optimal tip speed ratio (TSR) for the reference for the turbine. This was accomplished with a mixed sensitivity H-infinity tracking controller to optimize power output. The mixed sensitivity control was used to limit the bandwidth of the controller while also minimizing the tracking error. The methods are thus shown to be effective in wind speed estimation for two sizes of turbines and showed up to a 14.6 percent increase in power production the in maximum power point tracking region when compared to a baseline PI controller.