Research on VDG Control Strategy in Hybrid Energy Storage System of Photovoltaic DC Microgrid

With the access to many energy storage devices in the Photovoltaic DC microgrid, energy storage converters are also widely used, which have the characteristic of low inertia. Therefore, there are problems of low inertia in the optical storage DC microgrid system, which contains an energy storage converter, and the instability of the system causes by the fluctuation of micro-source and load mutation. In order to solve the existing problems, the paper proposes a Virtual DC Generator (VDG) control strategy based on the traditional double closed-loop control strategy in the hybrid energy storage system (HESS) of a photovoltaic DC microgrid. Applying this proposed control strategy can make the inertia and damping characteristics introduced into the converters, which provides sufficient inertia support for the optical storage DC microgrid and further improves the voltage quality. The microgrid system is modeled and analyzed based on VDG. The results show that the VDG control strategy effectively reduces power fluctuation of the hybrid energy storage and improves the stability of the microgrid system.