Multi-port DC-DC Converter for Interconnecting Bipolar DC Buses of Bipolar DC Distribution System

Abstract

This paper proposes a multi-port dc-dc converter that can interconnect bipolar dc buses of the bipolar dc distribution system. The bipolar dc distribution system has enhanced features compared with the unipolar dc distribution system. However, the bipolar dc bus requires the voltage balancing capability to balance the bipolar voltage levels under unbalanced load conditions. The proposed multi-port dc-dc converter can interconnect two bipolar dc buses, which can transfer bidirectional power flows between two bipolar dc buses and can balance their bipolar voltage levels without additional voltage balancers. The proposed converter is based on the dualactive-bridge converter. Therefore, since two voltage balancers can be eliminated at each bipolar dc bus, the proposed converter can improve power conversion efficiency, power density, and cost-effectiveness, thereby enhancing the performance of the bipolar dc system. A 3-kW experimental result is provided to prove the effectiveness of the proposed converter.