Bidirectional DC-DC Converter with High Voltage Step-Up/Down Ratio and Voltage Balance Capability for the Interconnection of Unipolar and Bipolar DC Microgrids

The importance of DC microgrids is growing in the realm of the today's electrical energy distribution networks. When it comes to the configuration of DC microgrids, several options exist. Yet, two structures have emerged as the most widely adopted: unipolar and bipolar DC microgrids. Consequently, their interconnection could be crucial for various applications. Given that these microgrids can operate at significantly different voltage levels, interconnection must account for this variation. Accordingly, this paper introduces a novel bidirectional DC‑DC converter with a high voltage step-up/down ratio for interconnecting these two DC microgrids. The converter boasts a non-isolated configuration, enabling the transfer of energy between DC microgrids while simultaneously supporting the balance of the bipolar infrastructure. Results from the experimental tests obtained from a laboratory prototype showing the capability to transfer energy in both directions are presented. The findings indicate that the proposed solution aligns with the anticipated outcomes.