Virtual synchronous generator (VSG) control has gained widespread attention in academia and engineering due to its active support advantages. However
it is difficult to balance transient stability and fault current suppression during faults. To address this
this paper proposes a joint control strategy of VSG voltage control and virtual impedance based on deep reinforcement learning. First
a mathematical model of a grid-forming converter based on a virtual synchronous generator is constructed. Second
the influence mechanisms of virtual impedance and voltage droop coefficient on fault current and system transient stability are revealed. Finally
a joint control strategy that adopts a combined offline training and online operation approach is designed and implemented
which balances fault current suppression and transient stability. Simulation results show that the proposed joint control strategy can effectively enhance the transient stability of the VSG-grid-connected system and significantly improve fault current limiting capability
thereby providing a key theoretical basis and technical support for enhancing the active support capability and security defense level of new-type power systems with a high proportion of new energy integration.
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