Consensus-based improved droop control for suppressing circulating current using adaptive virtual impedance in microgrids

To suppress large circulating currents due to slight differences in both phases and magnitudes of distributed generation (DG) output voltages in microgrid with considering mismatched line impedance, this paper proposes a circulating current suppressing method that employs distributed adaptive virtual impedance for islanded microgrid. The reactive power mismatch among the DG units is discovered by using the consensus control and then is used to adaptively regulate the virtual impedance of each DG. The circulating line currents among the DGs are effectively suppressed with fully distributed regulation of the DG virtual impedance by the proposed control strategy which requires no knowledge of the line impedances. Simulation results are presented to prove the effectiveness of the proposed method to suppress effectively the circulating current.