A Pre-synchronization Method for Grid-connection Based on Virtual Synchronous Generator

Abstract

The inverter is simulated as a synchronous generator that is friendly to large power grid, which can improve the absorption capacity of distributed power supply. However, when virtual synchronous generator (VSG) is connected to the grid, there will be a large current shock. Therefore, this paper proposes an improved pre-synchronization control strategy without phase-locked loop to realize smooth switching between VSG off-grid and grid-connected. Firstly, the principle of virtual synchronous machine is introduced. Finally, through simulation analysis, it is verified that the proposed pre-synchronization control method can realize the seamless switching of VSG between different modes, and it is simpler than the traditional pre-synchronization control algorithm, which verifies the effectiveness of the proposed control strategy.