Resynchronization of Grid-Forming Inverter -Stability Analysis and Design Guidelines-

Transition between islanded and grid-connected operations of grid-forming inverters requires a stable and well-designed voltage synchronization. In this paper, the voltage synchronization scheme of grid-forming inverter is addressed with the stability analysis and design guidelines. The stability conditions of vector Phase-Locked Loop (PLL) are given, and the design guidelines of controllers are provided to achieve the tracking performance. Implementation of 1.6 kVA grid-forming inverter is conducted to validate the proposed concept.