Research On Pitch Angle Control Strategy Of Large Wind Turbine Considering Aerodynamic Effect

In the current environment of energy exhaustion in many regions of the world,the research on wind power generation system is becoming a research focus in many countries.This paper considering the influence of the pneumatic effect on the wind turbine,the overall variable pitch control strategy of the large wind turbine is studied.With the 5WM large variable pitch wind turbine,the fuzzy PID(FPID)and the fractional fuzzy PID(FOFPID)are proposed to improve the performance of the variable pitch angle control.The main work is summarized as follows:(1)First analyzed the aerodynamic characteristics of wind turbine,this paper introduces the leaf element characteristics,betz theory.The characteristics of controlled objects such as blade force of wind turbine and the operation state of variable pitch wind turbine are analyzed.Concluded that the variable pitch ring unit power regulation principle,for further research of wind turbine system wind speed modeling pitch control laid a foundation.(2)Due to the non-linear and time-varying characteristics of the wind power generation system,the traditional PID control method is difficult to achieve a satisfactory control effect.Fuzzy control is an effective control strategy for objects that is difficult to establish accurate mathematical model.Therefore,this paper studies the advantages of fuzzy logic controller over PID controller in large variable pitch wind turbine control.Simulation results show that the fuzzy logic controller can improve the stability of the wind power generation system compared with the traditional PID controller.It lays a foundation for introducing the variable pitch control of wind turbine by the fuzzy control principle.(3)In order to further improve the control performance of the fuzzy logic controller,this paper puts forward two advanced variable pitch controllers,called fuzzy PID(FPID)and fractional fuzzy PID(FOFPID),to improve the power quality of wind power generation,reduce the fatigue damage of the transmission system,and maintain a stable power output.Meanwhile,in order to find the parameters of the controller,a chaotic evolutionary optimization method is used.The use of evolutionary optimization methods not only provides unknown parameters of the controller,but also guarantees optimality based on the selected objective function.All the optimization procedures were applied to the 5MW wind turbine model.The proposed controller will be validated using a FAST simulator developed by the American Renewable Energy Laboratory.Simulation results show that the FOFPID controller can achieve better performance and robustness than the FPID,fractional PID(FOPID),and gain scheduling PID(GSPID)controllers,while ensuring less fatigue damage at different wind speeds.