DC Impedance Stability Analysis of DC Microgrid Supplying Power to Passive Network

In the process of DC microgrid that supplies power to the passive network, the DC impedance of the inverter on the passive network side presents a negative impedance characteristic, which affects the stability of the system. Aiming at this problem, a DC impedance optimization control strategy is proposed. First, the typical topology and basic control methods of the DC microgrid that supply power to the passive network are introduced. Then, the DC impedance models of the converters at both ends are established respectively, and the reasons for the insufficient stability margin of the DC system are analyzed and put forward DC impedance optimization control strategy. Finally, the effectiveness of the proposed control strategy is verified by the controller hardware-in-the-loop experiment. The experimental results show that the proposed method can reduce the fluctuation of DC voltage, avoid the converter output power oscillation, and enhance the stability of the system.