2-VSG系统小扰动同步稳定性解析分析及稳定性增强策略

Virtual synchronous generator (VSG) introduces small-disturbance synchronization stability issues similar to synchronous generators. However, most existing research either relies on numerical analysis or focuses on particular operation scenarios, whose conclusions may not be generally applicable. Analytical analysis is the way to address this issue. This paper presents an analytical analysis of small-disturbance synchronization stability in a 2-VSG system considering various operation scenarios. First, the simplified model of the 2-VSG system is built and linearized. Its eigenvalues are analytically approximated, and the accuracy is verified. Then, two sufficient conditions for system stability from the perspective of operation scenarios and control parameters are derived. Hopf bifurcation and transcritical bifurcation are found, and their mechanisms and bifurcation conditions are analyzed. Further, it is proven that the uniform distribution of damping and inertia assists in avoiding bifurcations and ensures system stability under various operation scenarios. The inverse distribution strategy can be applied to improve the damping ratio of low-frequency oscillations only in systems where all VSGs supply power relatively uniformly. Case studies are provided to validate these conclusions. In summary, this paper provides a new perspective on the synchronization stability of the 2-VSG system and an optimistic damping distribution approach to enhance stability.