Modeling and Analysis of Grid-Tied VSC with Hybrid Synchronization Control

Power synchronization control (PSC) improves stability in weak grids, but may cause instability in strong grids. In contrast, phase-locked loop (PLL)-based synchronization shows opposite performance trends. To address this limitation, a hybrid synchronization control (HSC) that combines PSC and PLL is proposed from a new perspective. An impedance model of the grid-tied voltage source converter (VSC) is established, and Nyquist stability analysis is applied to evaluate the effect of hybrid coefficient on stability. The damping contribution of virtual admittance is also examined. Experimental results from hardware-in-the-loop tests validate the theoretical analysis.