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This paper proposes an enhanced transient control strategy for Virtual synchronous generators (VSGs) to address the challenges faced by grid-connected inverters, including DC-side voltage fluctuations, overcurrent, active power dynamic oscillations, and frequency overshoots during transient processes. Firstly, an active closed-loop small-signal model of the optical storage VSG is developed, and the effects of inertia and damping on the system stability are analyzed. Then, the power angular transient characteristics of the VSG are investigated, and the active power deviation factor is introduced to enhance the transient stability. The proposed strategy categorizes the operating phases according to the angular frequency deviation, the active power deviation, and the rate of change of these deviations while preserving the power angle characteristics of the VSG. By adaptively optimizing these parameters, the DC-side voltage fluctuations and overcurrent are effectively suppressed, and the active power and frequency overshoots are reduced. Simulation results verify the effectiveness of the strategy, with active power overshoot reduced by 9.43 %, voltage fluctuation reduced by 8.97 %, and frequency fluctuation stabilized within ±0.13 Hz. These improvements greatly enhance the dynamic performance of the optical storage microgrid and ensure grid stable operation in complex environment. |
