Modeling for Oscillation Propagation with Frequency-Voltage Coupling Effect in Grid-Connected Virtual Synchronous Generator

This letter proposes a modeling method for mechanism clarification on oscillation propagation in grid-forming virtual synchronous generator (GF-VSG) system considering the frequency-voltage coupling effect. Specifically, the physical significance of oscillation propagation between frequency and voltage of VSG has been clarified by the proposed Self-Stability-Loop-Model and Induced-Stability-Loop-Model. The proposed model and method can fill in the gap that conventional single-input-single-output system cannot identify this oscillations propagation phenomenon. It is also found that frequency oscillation are not always coupled with the voltage oscillation especially when the oscillation propagation is suppressed. Finally, the modeling and analysis are validated by simulations and experiments.