부산대학교 도서관

When the microgrid is switched off the grid connection, the pre-synchronization control link is added reasonably.The amplitude of the two can be achieved more consistent before the grid connection, so as to reduce the adverse effects of switching from the grid connection mode, and achieve the similar effect of seamless switching.This paper first models the microgrid and the virtual synchronous machine control system, then builds the traditional pre-synchronous module, analyzes its shortcomings, and proposes a pre-synchronous control strategy without phase-locking loop. Simulation results show that the new control strategy can make the amplitude and phase of VSG output voltage follow the grid voltage at the time point before the grid connection. After comparing the results, the feasibility and effectiveness of the proposed strategy are proved.