Study On Independent Variable Pitch Control System Of Direct Drive Permanent Magnet Wind Turbine

Direct-drive wind turbine with its excellent operating characteristics,has been widely applied,in the domestic wind power market.In the domestic direct-drive wind turbine machine manufacturers represented as Goldwind and XEMC.This paper focuses on the research on the variable pitch control technology of direct drive wind power generation,and studies the aerodynamic model,the operation control process,the load source and the electric pitch control of the direct drive wind turbine.In order to reduce the power fluctuation and fatigue load during the operation of the wind turbine,this paper focuses on the independent variable pitch control technology of the direct drive wind turbine.Firstly,the control mechanism and the source of the load of the wind turbine are analyzed.The process of wind turbine operation load sources has been studied based on wind turbine aerodynamics theory.Moreover,make a simulation by comparing the influence of wind shear,tower shadow effect and turbulent wind loads the wind turbine.The control object and control target of each stage of the wind turbine are described in detail,build a model based on load analysis of pitch control,The wind turbines under turbulent wind influence,the wind turbine pitch angle changes,power output characteristics and load components were observed.Secondly,Direct-drive wind turbine widely used electric pitch control systems,three blade pitch motors three independently controlled.In this paper,the structure of variable pitch motor,servo driver,backup power supply and main controller are designed in detail.Considering the serious influence of the power failure on the variable pitch system of the wind turbine,the power supply redundancy design of the variable pitch control system is carried out.The pitch motor adopts three closed loop vector control strategy of rotor based on flux orientation,the position loop,speed loop and torque loop shows the design and in Matlab/Simulink to build a variable pitch motor servo control model,through the simulation under the actual working condition variable propeller motor work conditions,the simulation results show that:the electric pitch has fast response speed and control precision,can quickly follow the change of pitch angle.Finally,the design of the LQG controller is designed based on the state space equation of individual pitch control strategy,using the method of modern control theory,LQG controller is a linear quadratic regulator(LQR)and Kalman filter is composed.In order to suppress the wind effect of disturbance signal to the wind tuebine,using adaptive anti jamming control(DAC)feedforward control,and finally build a simulation,the proposed control strategy can effectively reduce the fluctuation of wind turbine output power,and can reduce the load of wind tuebine each component.