Minimum Variance Control of Constant Power Output For Wind Energy Conversion System Above Rated Wind

When the wind speed is above the rated value, pitch angle is regulated to maintain the constant power output in order to limit the wind turbine speed and power because of the mechanical load limit of the mechanical structure and the electric load limit of the electric components. After the mathematical model for the wind energy conversion system and the mechanism of pitch angle control system was analyzed, a modified adaptive minimum variance control (MVC) method with extended predictive step length and flexible control law was proposed. This control strategy was applied to realize the rated power output above the rated wind and the desired pitch controller was designed. Simulation results show that rated power output is maintained by the controller above the rated wind and the controller is robust even if there exists an uncertainty.