This paper proposes a non-isolated bidirectional DC-DC converter for energy storage systems. On the battery side, two sets of coupled inductors are used to achieve high voltage gain and reduce current ripple on the low-voltage side. The DC bus side employs a three-level neutral-point clamped structure to mitigate the problem of high switch voltage ratings. In addition, finite element simulation analysis was performed on the design of magnetic components, and an analysis of using two magnetic materials and different gap distributions on the magnetic core was proposed. Finally, following the design process outlined in this paper, a converter with a low-voltage side of 60 V, a high-voltage side of 400 V, a rated power of 300 W, and a switching frequency of 100 kHz was developed and tested. Experimental results demonstrate the feasibility of the proposed bidirectional topology, achieving a maximum efficiency of 93.72% in step-up mode and 92.33% in step-down mode under the condition of a 300 W output power.
