Stability Analysis of Isolated Operation Mode of DC Distribution System with Battery Energy Storage

For the application scenario of DC distribution system supplying for AC passive network using voltage source converter (VSC), the bidirectional DC-DC converters should be connected with the battery energy storage devices to maintain the DC voltage unchanged. Firstly, the small signal dynamic equation of VSC is established by treating the AC load as constant power model for modeling simplification. Secondly, the control strategies of DC voltage-controlled and power-controlled DC-DC converters are studied as well as the small signal models of the two types according to the voltage stability requirement of DC bus. Thirdly, taking the DC network system as the connection nodes, the integrated state space model of whole system is established. The influence of steady-state operating points, main circuit parameters and the control system parameters on the stability of the DC distribution system is studied. Finally, the correctness of modeling and conclusion are verified by the electromagnetic transient simulation models.