A Leader-Follower Control for Negative-Sequence Current Sharing Among Grid-Forming Sources in Islanded Microgrids

Negative-sequence (NS) current sharing among different grid-forming (GFM) sources is a critical issue in islanded microgrids (MGs). Existing sharing strategies only focus on the NS current distribution among inverter-based resources (IBRs). However, existing approaches have not fully considered the NS current sharing among IBRs and SGs and are easily affected by line impedances. In this paper, a leader-follower-based approach is proposed for the NS current sharing among IBRs and SGs. The leader IBR, attempting to regulate the bus NS voltage to zero, generates the total NS current references. The NS current references are distributed to follower IBRs. After the IBRs’ NS currents track the references, the SGs’ NS currents is subsequently determined. The proposed control strategy is verified through both simulation and experimental testing on a converter-based hardware testbed.