Virtual Synchronous Machine Control Strategy for Interface Converter in Hybrid Micro-grid

The interface converter, which is used to connect the AC micro-grid and DC micro-grid, can operate as rectifier and inverter in AC/DC hybrid micro-grid to control bidirectional power flow. This paper proposes a virtual synchronous machine control strategy based on two operation modes of synchronous machine, which operates as both generator and motor. The voltage and power output characteristics of the interface converter and the synchronous motor are compared and analyzed. Then, the virtual synchronous machine control models are designed, including the virtual frequency controller, excitation regulator and the inertia unit. Finally, the interface converter model was established in MATLAB/Simulink, which operated in two modes. The simulating results indicate that the proposed virtual synchronous machine control strategy can reduce the fluctuation of frequency and maintain stability of DC voltage during a sudden load changing.