Transient energy transfer of wind-photovoltaic-storage grid-connected system under virtual synchronous coupling

In the new power system, the efficient capture of transient energy by a virtual synchronous generator (VSG) will be the key to improve the grid-connected stability of wind-photovoltaic-storage. This paper first analyzes the virtual synchronous coupling relationship between the VSG and the synchronous generator (SG), and constructs the dynamic model of grid-connected system. Secondly, based on the Hamiltonian theory, the transient energy transfer characteristics between the VSG and the SG under the virtual synchronous coupling are analyzed, and the conditions for the VSG to completely capture the transient energy is obtained, and a virtual inertia control strategy based on the efficient transfer of transient energy is proposed. Finally, a 9-node simulation system is built to verify that the proposed control strategy can significantly improve the performance of VSG in suppressing power oscillations and frequency changes.