Mechanism Analysis for Oscillation Transferring in Grid-Forming Virtual Synchronous Generator Connected to Power Network

This letter proposes a new modeling framework for stability assessment in grid-forming virtual synchronous generator. Specifically, the mechanism of self-stability and induced-stability have been clarified with frequency and voltage magnitude. The models of frequency self-loop, voltage self-loop, frequency induced-loop, and voltage induced-loop are derived to comprehensively identify whether the mechanism of the oscillation is caused by the self-stabilizing loop or by oscillation transferring. By mathematical derivation combined with logical judgment of physical significance, it is found that frequency has the same closed-loop transfer function with that of active-power. Finally, analysis is validated by experiments.