Impact of Phase-Locked Loop on Transient Stability by Phase Portrait Analysis Method

As the proportion of new energy generation increases, voltage source converter (VSC) becomes a key energy conversion electronic component, and transient stability analysis of VSC system becomes topical issues. Usually VSCs are synchronized with the AC grid using a phase-locked loop (PLL). In this paper, a simplified current-controlled inverter grid system model and a phase-locked-loop dynamic model are established, the equal-area method and the phase portrait analysis method are introduced and compared, and the two analysis methods are explained by a simple example.