A Novel VSG-Based Active Power Control Method for Mitigating Output Frequency Variations in Grid-Forming Converters

Grid-forming converters are crucial for stable operation in low-inertia power systems. Conventional virtual synchronous generator (VSG)-based control methods inherently introduce steady-state errors due to structural limitations and coupling between inertia emulation and load-sharing functions. Although recent PI-and IP control-based active power controllers reduce these errors, PI methods suffer from overshoot, and IP methods are vulnerable to frequency instability caused by power ripple or rapid load variations. In this study, these issues are addressed by adopting a novel VSG-based active power control strategy that incorporates a low-pass filter into the IP controller and designs the resulting third-order dynamics. The method can suppress frequency variations without overshoot when closed-loop poles are placed on the negative real axis and a zero faster than the dominant poles are added. The validity of the proposed control method is verified via hardware-in-the-loop experiments.