An Active Damping Technique for Current-Mode Droop Control in DC Microgrids

Droop-controlled dc microgrids are widely used in the field of renewable energy generation. In order to endow fast transient response to the source converters, current-mode droop control approaches are preferred rather than the voltage-mode counterparts. However, a small droop gain in current-mode droop-control will bring instability challenges to the system. In this paper, a novel impedance-shaping based active damping technique is proposed to facilitate better stability performance of the current-mode droop-controlled system. A detailed impedance model is established to analyze the system stability under different operating conditions. The theoretical results obtained in this paper are validated by simulation results with switching models.