Research On Power And Load Control Of Large-scale Wind Turbines Based On Active Disturbance Rejection

As the power and size of wind turbines increase,under the influence of wind shear and tower shadow effects,the blades and hubs will also bear unbalanced loads.These loads are transmitted to the generator through drivetrain,which in turn affects the force and service life of the wind turbine.In addition,changes in wind speed will also cause large fluctuations in the output power of the generator,which will affect the quality of power.Therefore,the use of appropriate control strategies to reduce power fluctuations and reduce the unbalanced load of the blades has important research significance for improving the quality of power generation and increasing the service life of wind turbines.The main research contents of the thesis are as follows:(1)based on the aerodynamic theory,the aerodynamic load of the wind turbine blades is analyzed in detail,the common wind speed model is established according to the GL specification,and the influence of wind shear and tower shadow effect on wind speed is discussed.The multi-body dynamics software SIMPACK was used to establish a complete wind turbine model,and briefly introduced the operating area of the wind turbine and its corresponding control strategy,which lays the theoretical foundation for the construction of the variable pitch control model later.(2)based on the simplified two-mass wind turbine drivetrain model,this paper derives the PI variable pitch controller parameters based on gain scheduling.Aiming at the output power fluctuation caused by wind speed changes and unknown disturbances in the system,a variable-speed pitch control strategy based on active disturbance rejection is proposed.Among them,the active disturbance rejection control can estimate and appropriately compensate the unknown disturbance of the system to suppress the fluctuation of the output power.Through SIMPACK and Matlab/Simulink co-simulation,two variable pitch control strategies are compared and analyzed.The simulation results show that the proposed control strategy can reduce power fluctuations and has strong anti-interference ability.(3)this paper analyzes the linearized model of the wind turbine blade,and transforms the unbalanced load on the rotating blade into the tilt moment and the yaw moment under the stationary hub coordinates through the d-q axis transformation.Aiming at the unbalanced load on wind turbine blades and hubs caused by wind shear and tower shadow effect,a BP neural network PID individual pitch control strategy based on auto disturbance rejection is proposed.Among them,the active disturbance rejection control is used to suppress the fluctuation of the output power;the BP neural network PID controller is used to reduce the unbalanced load on the blade and the hub.Co-simulation analysis is used and compared with traditional PI individual pitch control.The results show that the proposed control strategy can reduce the unbalanced load of wind turbine blades and hubs while reducing power fluctuations.