Research On Operation Strategy Of AC/DC Hybrid Microgrid Based On Droop Control

Large-scale grid integration of distributed energy is the key to solving the problem of fossil energy exhaustion facing the world.Therefore,microgrid is one of the important ways to convert clean energy into electric energy and increase the consumption rate of renewable energy.In the research of microgrid,it has important practical significance to control issues such as the stability of load power supply,maintaining the balance of system power supply and demand,and ensuring the stable operation of the system.In response to this,this paper proposes a droop control strategy based on sliding mode control in the AC/DC hybrid microgrid.First of all,in order to study the operation control of the AC/DC hybrid microgrid,an AC/DC hybrid microgrid including wind,solar,and storage is established.The mathematical model and operating characteristics of each distributed power supply are analyzed and built in Matlab/Simulink.The simulation model simulates external force interference after changing the light intensity,wind speed and load size to perform simulation analysis to ensure the safe and stable operation of the entire hybrid network system.Secondly,through the topology diagram and operation mode of the AC-DC hybrid microgrid,the frequency modulation characteristics and power characteristics of the traditional inverter droop control strategy are deeply studied,and a nonlinear control method—variable structure control(sliding)is analyzed.Sliding Mode Control(SMC)method,and analyze and design the controller of this control method;there are many neglects and approximations in the design and calculation process of nonlinear inverter,so the droop control inverter adopts dual closed-loop PI control strategy has poor anti-interference ability and robustness.On this basis,the SMC-based droop control strategy is simulated in the AC/DC hybrid microgrid.Finally,in view of the different output and load changes of each micro source,several working conditions are designed to simulate and analyze the pros and cons of the droop control inverter using PI control and SMC.The simulation results verify the feasibility of the established model and control strategy.