Mitigation of circulating currents for proportional current sharing and voltage stability of isolated DC microgrid

•This paper proposes distributed dynamic consensus-based control for voltage stability and proportional current sharing of isolated DC microgrid.•The effect of circulating currents on the current sharing is analyzed and mitigated. Proportional current sharing among converters is obtained for different line resistances and power rating of converters.•A modified droop control is proposed, which can mitigate circulating currents and guarantee proper sharing ratio by incorporating average circulating current control.•A distributed consensus-based secondary control is presented with dynamic averaging of voltage and circulating current. Droop control is commonly adopted method for sharing load current among parallel-operated DC–DC converters in DC microgrid. However, when different power ratings converters are parallel connected, it gives rise to circulating currents, which deteriorates current sharing. This paper proposes consensus-based distributed secondary control for voltage regulation and current sharing with different rating converters connected. A modified droop control is presented by employing average circulating current control strategy for mitigation of circulating currents. Moreover, to compensate the voltage deviation caused by droop control, a dynamic consensus-based average voltage control is designed. The proposed algorithms can achieve proper current sharing ratio among converters and also guarantee low voltage regulation. The effect of line resistance and communication delay is also considered and better performance is achieved. Simulation and experimental tests on two DC–DC parallel buck converters based microgrid systems show the effectiveness of the proposed method.