A Common Ground Non-Isolated Bidirectional DC-DC Converter with Low Stress and High Conversion ratio for Utilization in DC Micro-Grids

With the increasing integration of renewable energy sources and energy storage systems in DC micro-grids, there is a growing demand for bidirectional DC–DC converters that combine high efficiency, wide voltage conversion capability, and simple control structures. A non-isolated bidirectional DC–DC topology is introduced in this study, suitable for micro-grid utilizations, aiming to establish a common ground. The converter comprises four primary switches, supplemented by four capacitors and three inductors. Its straightforward configuration, high voltage gain conversion ratio, minimal voltage stress on switches, and common ground connectivity constitute key advantages. Additionally, the converter offers good step-up/step-down voltage conversion ratio, e.g. output voltage four times higher(lower) for step-up (step-down) mode with a fifty percent duty cycle. With its simple architecture and having only two modes in each switching period for both step-up and step-down operation states, the control for this topology becomes streamlined. The paper conducts a comprehensive analysis encompassing steady-state considerations in both operational directions, assessment of voltage stress on switches, and juxtaposition with alternative bidirectional converters. To prove the presented theoretical analyses, a 200 W laboratory model of the circuit is constructed and evaluated. The efficiency of the introduced circuit at nominal power is 92 percent.