Small-signal Stability Analysis of Multiple Grid-connected Virtual Synchronous Generators

At present, the stability of virtual synchronous generator (VSG) is mainly studied in micro-grid or single grid-connected VSC, and the stability of multiple grid-connected VSCs still lacked the research. This paper builds the small signal models of multiple grid-connected VSCs, and the influence of VSC control parameters (active power droop coefficient, virtual inertia, etc.) on the characteristic roots and stability of the system are discussed. Besides, the stability difference between multiple grid-connected VSC and single VSC are compared. Finally, the correctness of small signal modeling and results analysis are verified by simulation. The results of this paper show that when the parameters of multiple VSC grid-connected systems are the same, the stability of multiple VSCs is basically the same as that of single VSC system, while the system oscillation mode may have a significant difference when there are some differences in VSC parameters.