Synchronization Stability Analysis of PLL-Based Grid-Connected VSC System by Voltage Space Vectors

This paper focuses on synchronization stability analysis of the power system, in which power electronics are synchronized by the phase-locked loop (PLL). It provides new insight into the synchronization stability of power electronics from the voltage perspective. The synchronization stability analysis based on space vector is carried out by establishing a simplified model of the grid-connected voltage source converter (VSC) system. Without complex mathematical calculation, the existence criterion of equilibrium points and the criterion of transient instability dominated by the unstable equilibrium point (UEP) are derived, respectively. With the proposed method, synchronization stability can be determined by the voltage space vectors, which are more observable in potential engineering applications. At the end of this study, the steps of the synchronization stability determination by voltage space vectors are summarized, and the effectiveness and applicability of the proposed method are demonstrated by numerical simulations performed on the PSCAD/EMTDC platform.