Comparative study of current redistributor's topologies for mitigating unbalanced currents in bipolar DC microgrids

Whereas bipolar DC microgrid has several advantages over monopolar DC grid [1], [2], its disadvantages cannot be underestimated. The currents in the pole lines can become asymmetric, and the neutral conductor carries non-zero current. To eliminate the current imbalance caused by unipolar loads/generators in bipolar DC microgrids, different types of current redistributor have been proposed and implemented [3], [4]. However, the control design, switching currents and required operational power of the current redistributors have not been clearly discussed. This paper focuses on comparing single half-bridge and three phase half-bridge current redistributors by simulation and experimental validation.