Design of Real Time Switching System for Multi Energy Microgrid and Off Grid based on Virtual Synchronous Machine

In the process of multi-energy microgrid on-grid and off-grid switching, how to achieve smooth transition and efficient management has become an urgent problem to be solved. This paper aims to design a multi-energy microgrid on-grid and off-grid real-time switching system based on virtual synchronous machine. By building a virtual synchronous machine model, real-time monitoring and coordination of various energy sources in the microgrid are realized. First, the system architecture is established, including virtual synchronous machine controller, energy management system, communication network and load prediction module. Then Simulink is used to model and simulate the system, and the switching strategy is designed, including the power balance algorithm in the on-grid mode and the frequency and voltage control algorithm in the off-grid mode. During the switching process, the system first performs load forecasting to ensure that the energy supply and demand can be balanced before switching; then the virtual synchronous machine controller adjusts the output of each energy source to ensure that the frequency and voltage of the power grid remain stable during the switching process. The average frequency stability of the system in the on-grid mode is within 98.9%, and seamless switching can be achieved within 6 seconds in the off-grid mode.