Design and Analysis of a Novel Transformer Less Non-Isolated Bi-Directional DC-DC Converter for Applications in Isolated DC Microgrids

Energy storage is pivotal in isolated microgrids for effective power management during fluctuating load conditions. This necessitates a bidirectional converter capable of both charging and discharging energy. This paper presents a novel, non-isolated, transformer less bidirectional DC-DC converter (BDC) to address this requirement.It offers numerous advantages which includes high gain, high efficiency, simplified circuit structure, reduced switching components and switching losses, reduced voltage stress, wide voltage range through synchronous rectifier zero voltage switching (ZVS). The proposed converter facilitates bidirectional power flow, operating in both buck mode (charging) and boost mode (discharging) between the battery and a 400V DC bus, accommodating a wide range of voltage gain ratios. Comprising three switches, two inductors, and four capacitors, the converter's structure was simulated using MATLAB/SIMULINK. Simulation results indicate a voltage gain of 6 in boost mode for the proposed converter, surpassing the conventional converter's gain of 3.5. In buck mode, the proposed converter achieved a voltage gain of 0.72, outperforming the conventional converter's 0.68. These findings highlight the superior performance of the proposed converter.