Comparing investigation for a bi-directional isolated DC/DC converter using series voltage compensation

This paper discusses a bi-directional isolated DC/DC converter using series compensation method. The proposed converter consists of a high efficiency resonance full-bridge converter and a series converter. This proposed circuit regulates the output voltage by the series converter, which provides only the differential voltage between the input voltage and the output voltage, which is closed to the nominal voltage. In this paper, four types of the auxiliary circuits are investigated in term of loss. The relationship between the loss element and efficiency characteristics is clarified. The validity of the proposed circuit is confirmed by the loss calculation, with a maximum efficiency of over 94% at 2kW. Moreover, the experimental results confirmed that the proposed circuit, which converts 48-V to 380-V at 1kW, achieves the maximum efficiency of 93.0% at the nominal input voltage region.