Research On Microgrid LFC Method Dominated By Wind Power

As the contradiction between social development and environmental protection has become increasingly prominent,microgrids composed of clean energy such as wind energy,solar energy,and tidal energy have developed rapidly.However,the intervention of renewable energy also brings new challenges to the safe operation of microgrids.When considering the dominant position of wind power in the microgrid,the output characteristics of wind power have a decisive impact on the stability and reliability of the microgrid.Therefore,how to adjust the output power of wind power to participate in the load frequency control of the microgrid(Load Frequency Control(LFC)process to achieve the balance of microgrid load power is a necessary condition for the safe and stable operation of microgrid.This article studies this,and the specific content is as follows:First,take the wind and diesel micro-grid system as the object,analyze the composition structure and output characteristics of each power generation unit,and derive the mathematical model of each unit;and based on the basic principle of load frequency control,the realization mechanism of primary frequency modulation and secondary frequency modulation,To build a wind power-led wind power diesel microgrid LFC system model.Then,the output characteristics of Doubly Fed Induction Generator(DFIG)and Maximum Power Point Tracking(MPPT)control methods are discussed,and the three output control methods of DFIG are introduced in detail.: Virtual inertia control,step inertia control and pitch angle control.The corresponding relationship between each output control method and the microgrid’s primary frequency modulation and secondary frequency modulation on the time scale is analyzed,and the demand and feasibility of wind power dominant microgrid load frequency control are discussed.On this basis,in response to the need for rapid primary frequency modulation,a DFIG torque-limiting inertia control method is designed,and a method based on pitch angle compensation is proposed to cope with the secondary frequency drop caused by the conventional torque-limiting control method during the speed recovery phase.problem.In response to the steady-state demand for the performance of the secondary frequency modulation control performance,the DFIG participating in the wind and diesel micro-grid frequency modulation system and process was analyzed,and the active pitch angle control mode was designed.The PSO algorithm was used to optimize the two degree of freedom PID(Two degree of freedom PID,The design of the2-DOF-PID)controller can actively adjust the pitch angle in a relatively large range,so that it can achieve the control goal of the second frequency modulation of the microgrid.Finally,the simulation verification is carried out in the Matlab/Simulink system.The simulation results show that the proposed torque-limiting control method based on pitch angle compensation can provide effective frequency support for the system,increase the lowest frequency point,smooth frequency fluctuations,and slow down the rotor The second drop in frequency caused by the speed recovery improves the dynamic response capability of the microgrid system.The proposed 2-DOF-PID second frequency modulation method for controlling the pitch angle of the wind turbine can reduce the maximum deviation and oscillation amplitude of the system response when the microgrid is subjected to continuous load disturbance,and effectively improve the anti-disturbance of the microgrid system,To ensure the stability and safety of microgrid operation.