Large-Signal Grid-Synchronization Stability Analysis of PLL-Based VSCs Using Lyapunov's Direct Method

Grid-synchronization stability (GSS) is an emerging issue of grid-tied voltage source converters (VSCs), which can be provoked by severe grid sags. Although a qualitative understanding the mechanism behind loss synchronization has been acquired in recent studies, analytical method for quantitative assessment GSS VSCs still missing. To bridge this gap, dedicated Lyapunov function analytically proposed, and its corresponding criterion analysis rigorously constructed. Both theoretical simulation result demonstrate that proposed provide credible evaluation compared to previous EAC/EF-based method. Therefore, it applied fast as exemplified letter, well tool some GSS-related issues, e.g., GSS-oriented parameter design stabilization control.