Bipolar Bidirectional DC-DC Converter for Medium and High Voltage DC Micro grids

This paper proposes a soft switching technique for a non-isolated bipolar bidirectional DC-DC converter with series connection of modular bidirectional DC converters suitable for both small and medium scale bipolar DC microgrids to achieve high voltage gain. The soft switching technique is implemented by turning-on all the power devices automatically at zero current during discontinuous conduction and turning-off is achieved by using an auxiliary devices in the circuit. Soft switching, high efficiency, transformer less structure and inherent control for voltage balance make this converter employable in bipolar DC grids. Further proposed converter can be used in HVDC applications and electric vehicle charging stations. Detailed analysis and simulation results are presented to highlight the merits of this proposed topology.