Stability Analysis of DC Microgrid with Multi-converter Parallel Operation Based on Impedance Model

In the DC microgrid, in order to solve the DC bus voltage fluctuations caused by the randomness of distributed energy, multiple groups of DC bus voltage control units (DC BVC) are connected to the system through converters. The mechanism of the influence of the parameters of the converter on the stability of the DC microgrid system is still unclear. In this regard, this paper establishes the small signal model of DC BVC and load, and analyzes the output impedance characteristics of the source-side converter. Secondly, considering the influence of the interaction of multiple converters on the stability of the system, the equivalent impedance model of the DC microgrid is established. And according to the impedance matching principle, the influence characteristics of system parameters, converter control parameters and load power on system stability under different setting schemes are analyzed. Finally, the influence of the matching of multi-converter control parameters on system stability is analyzed.