Small signal modeling and stability analysis of multiple grid-forming converters in energy storage station

With the development of new-type power systems, the application scenarios of grid-forming (GFM) converters in energy storage stations have been continuously expanded, but its large-scale application has brought more and more serious stability problems. In the multi-machine parallel system, there is a more complex coupling relationship between the devices. To explore the influence of the law of frequency stability on the multi-machine system. Firstly, based on the principle of the grid-forming energy storage converter, a small signal model of the grid-forming energy storage multi-machine parallel system is established. Secondly, the eigenvalue root locus method is used to analyze the influence of connection impedance and active loop control parameters on the system eigenvalue, and the mutual coupling mechanism between the converter and the converter, the converter and the whole system is clarified, to obtain the influence law of frequency stability of the grid-forming converter multi-machine parallel system. Finally, the effectiveness of the established small signal stability analysis model is verified by simulation. • a small signal model of grid-forming energy storage station is established • the influence of key parameters on the system is analyzed by eigenvalue method • the mutual coupling mechanism between units and its influence are analyzed