Impedance Analysis and System Stability Studies of Converter in DC Microgrid

For the impedance characteristics of the converters and its stability problems in DC microgrid.the output impedance of converter was investigated from system-level height.Moreover,in order to obtain the open-loop output impedance,small signal modeling of the Boost type DC-DC converter in CCM was derived.Based on analysis of the small signal model and effect factors for the closed-loop output impedance under droop control some conclusion were drawn to analyze the stability of DC microgrid.Finally,according to impedance ratio criterion,the stability of the system which was influenced by parasitic capacitance was analyzed.Simulation results are also given to demonstrate the correctness of the analysis.