A Bidirectional Buck–Boost DC–DC Converter with Continuous Input and Output Currents for Energy Storage Systems

Abstract

This paper presents a novel non-isolated bidirectional buck–boost DC–DC converter capable of regulating the output voltage over a wide range of input voltage and load variations for Energy Storage Systems (ESS) applications. Unlike many existing bidirectional converter topologies that emphasize either high voltage gain or continuous current operation, the proposed converter features continuous input/output currents, reduced voltage and current stresses on switches, and improved gain linearity in the buck region. These features contribute to lower current ripple, simplified converter control, improved semiconductor device utilization, and higher conversion efficiency. The operating principles and steady-state characteristics of the proposed converter were analyzed in detail and a comparative analysis with recently reported bidirectional DC–DC converters was conducted with respect to voltage gain characteristics, current continuity, and switch voltage/current stresses. A 500 W laboratory prototype operating at 40 kHz was developed to validate the theoretical analysis. The experimental results agree well with the theoretical analysis, confirming stable bidirectional power transfer, continuous input/output current operation, reduced switch stresses, and achieving a peak efficiency of 97.18%, demonstrating the suitability of the proposed converter for energy storage applications.