Fractional order proportional integral (FOPI) controller design for the hydraulic variable pitch wind turbine system

Fractional order proportional integral (FOPI) controller was presented to deal with the characteristics of the hydraulic variable pitch wind turbine system, such as slow time-varying, nonlinearization, wind load frequently changing and serious random disturbances. Based on the Flat phases, combined with traditional control theories, phase margin and amplitude margin method, the parameters of the FOPI controller was determined. The simulation results show that FOPI controller has better control effect and excellent robustness compared with normal PID controller.