Enhancement and Analysis of Transient Stability of VSC with Anti-Windup Augmented Phase-Locked Loop

Maintaining stability of grid-following VSC during severe grid faults remains an open problem, where phase locked loop (PLL) plays a critical role. Previous research on PLL and transient stability either introduces time delays which degrades the system dynamics, or is computationally expensive. In this paper, an improved SRF -PLL configuration with an anti-windup compensator is proposed to improve the transient stability of the grid-following VSC. Based on the linearized model of PLL, an optimization problem is formulated to determine the parameters of the anti-windup compensator. Simulation results illustrated that the proposed PLL can tremendously enhance the transient stability of grid-following VSC compared with the existing PLLs.