A novel bi-directional DC-DC converter for distributed energy storage device

This paper presents a high efficiency, low-cost bidirectional isolated dc-dc converter for distributed energy storage device (DESD). Derived from dual active bridge (DAB), the proposed converter consists of a half-bridge circuit at high voltage side and a push-pull circuit with active clamp at low voltage side. The proposed topology is attractive in low voltage and high current applications and it also reduces the number of switching transistors such that the cost and complexity are considerably reduced. With single phase-shift control strategy, all the switches operate in zero-voltage switching (ZVS) condition without increasing circuit complexity. Besides, planar transformer is implemented where the low voltage windings consist of PCB trace and external copper foils. A 380V to 12V DC, 500W DESD hardware prototype has been designed, fabricated, and tested. Experimental results verify the validity of the proposed bi-directional converter, which has 97.3% peak efficiency and maintains greater than 92% efficiency over a load range between 100W and 600W.