Synchronous Frequency Resonance Stability of Vsg Grid-Connected Systems Based on [P Q]- [$\omega U$] Admittance Model

This paper focuses on the issue of synchronous frequency resonance (SFR) in virtual synchronous generator (VSG) grid-connected systems. Based on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left[\begin{array}{lll}P &amp; Q\end{array}\right]-\left[\begin{array}{ll}\omega &amp; U\end{array}\right]$</tex> admittance model of VSG grid-connected systems, the selfstability of the converter subsystem and its interactive stability with the grid subsystem are investigated. First, the self-stability of the converter subsystem is analyzed, and a simplified self-stability criterion is presented. Then, based on the determinant-based generalized Nyquist criterion (GNC), the interactive stability between the converter and grid subsystems is analyzed, highlighting the influence of control parameters on stability and the risk of synchronous SFR due to impedance interactions. Finally, simulation results are provided to validate the accuracy and effectiveness of the stability analysis.