A Novel Boost Derived Input-Parallel Output-Series DC-DC Converter for Bipolar DC Nanogrid

While bipolar configurations in DC nanogrids offer numerous advantages, they typically rely on a substantial number of standalone DC-DC converters to supply power to both poles of the grid. Furthermore, voltage imbalances frequently occur due to unequal load distribution between the poles. To address these challenges, this paper describes a novel Input Parallel Output Series Boost-Cuk (IPOSBC) converter that transfers energy from a single source to both poles, effectively reducing the overall converter count in the DC nanogrid system. The proposed converter features an interleaved structure that minimizes source current ripple, delivers a bipolar output with enhanced voltage gain, and achieves zero-voltage switching for two switches, thereby improving overall efficiency. Additionally, the paper presents a unique voltage imbalance mitigation strategy that leverages the proposed converter's bidirectional operation. In this approach, the converter absorbs the neutral line current and redistributes it equally between the positive and negative poles of the bipolar DC nanogrid, balancing the pole voltages without the need for an active power source connected to its input terminals. This reduction in neutral line current also decreases the overall line losses in the nanogrid system. The feasibility and effectiveness of these techniques are validated through theoretical analysis and experimental results from a 250W hardware prototype of the IPOSBC converter.