Stability Analysis for Energy Storage Converter with VSG Control

This paper analyzes the entire virtual synchronous generator (VSG) control system including battery energy storage system (BESS) by state space model, and compares the model with the conventional model whose DC-side is a constant voltage source. Firstly, the model of converter including BESS is established, and its accuracy is verified by frequency-scanning. On this basis, the model including BESS is compared with the conventional model whose DC-side is a constant voltage source, and bode diagrams are applied to analyze the impact of parameter changes on model differences. Then the influence of BESS on integral system stability is studied in detail, and the effects of different parameters on low frequency oscillation are analyzed by root locus. Additionally, according to the impedance expression of the BESS, the auxiliary conditions for PI parameters selection are designed and verified from the view of phase margin. Finally, the model is verified by RT-LAB experimental platform.