Abstract. Large-capacity energy storage systems can meet the demands of micro-grid and the smart grid. But the traditional control method is difficult to realize plug and play and seamless switching between different operation modes, it has limited the roles of large-capacity energy storage system. Virtual synchronous generator (VSG) has became a hot topic in recent years because of its synchronous generator external characteristics, such as inertia, frequency voltage regulation and automatic phase lock. A novel control strategy based on VSG is proposed for large-capacity energy storage systems. Firstly, the topological structure characteristics of large-capacity energy storage systems and the basic principle of the novel control strategy based on VSG are introduced, then setting method of the control strategy parameters is given. Finally, the proposed control strategy is verified by simulation and experiment. The results of simulation and experiment show that large-capacity energy storage systems based on this novel control strategy can automatically adjust the active power output according to the grid frequency changes and realize seamless switching between connected-grid and off-grid mode.

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