Abstract：During the transition of a microgrid inverter from grid-connected mode to islanded mode and vice

versa，pre-synchronization measures are necessary under the virtual synchronous generator （VSG） control

architecture to prevent voltage waveform distortion and current surges. A VSG-based parameter-optimized presynchronization method was proposed for microgrid inverters aimed at achieving seamless transitions between the two operating modes. By fine-tuning the VSG control parameters，this method seeks to optimize system

performance and ensure appropriate power distribution，thereby enhancing the performance of mode switching

between grid-connected and islanded operation. To validate the effectiveness of the pre-synchronization control

strategy and optimized parameter design，the PSCAD simulation platform was utilized to develop the simulation

model. The results confirm the efficacy of the proposed approach，providing theoretical reference and technical

support for the application of microgrids in grid-connected scenarios.

      Key words：microgrid；virtual synchronous generator（VSG）；pre-synchronization；parameter-optimized