Improved Pre-synchronization and Grid Connection Strategy Based on Virtual Synchronous Generator

To enhance the inertia and damping of power grid, enhance the support ability of voltage and frequency, virtual synchronous generator (VSG) technology is widely applied. An improved pre-synchronous grid connection strategy is proposed to address the issues of large power oscillations and current surges during VSG off grid switching. Under the coordinate αβ axis, a method similar to reactive power calculation is used to obtain the adjustment amount of VSG output voltage, and through control, fast and accurate synchronization with grid voltage is obtained to achieve smooth switching of VSG off grid. Finally, the effectiveness of the proposed improved pre-synchronization grid connection strategy is verified through simulation and a 50 kV/A prototype is built to prove the feasibility of proposed method.