Research On Operation Control Of Small AC And DC Hybrid Microgrid

With the development of society,the traditional energy sources such as petroleum,coal and other fossil fuels are rapidly consumed,and the environmental pollution is becoming more and more serious.The clean energy power generation system,such as solar energy and wind energy,makes up the micro grid in the form of distributed power supply,which not only alleviates the energy crisis,but also is an important supplement to the remote area and the area of electricity shortage.As a medium of distributed power supply to microgrid,there are many types of power electronic conversion devices,and the control methods are generally flexible.However,because of the different power generation capacity of different types of distributed power,the control of power balance and voltage frequency stability is relatively complex,and high degree of difficulty..The AC micro grid and DC microgrid have advantages and disadvantages.Combined with the advantages of AC and DC hybrid microgrid,the use and complexity of the power electronic conversion device in the middle transformation are reduced,and the loss of energy conversion is reduced.In this paper,the structure and working principle of the photovoltaic power system,the wind power generation system and the storage battery energy storage unit are studied in detail.The mathematical models of each module are established.The simulation models are set up in MATLAB/Simulink.The simulation results verify the characteristics of each micro power supply.The overall operation control strategy of the hybrid microgrid and the control method used in the micro power supply control are studied and designed.In MATLAB/Simulink,a microgrid system model based on the master slave control strategy is built,and the simulation module of constant voltage constant frequency control,constant power control and droop control for micro power control is established.Through the simulation model,the simulation of the hybrid microgrid operating in the grid mode,the island mode,the grid mode switching to the island mode and the island mode switching mode to the grid mode is simulated,and the correctness of the whole control strategy and the micro power control method adopted in this paper is verified.