High step-up/down DC-DC bidirectional converter with low switch voltage stress

In this paper a high step-up/down DC-DC bidirectional converter is presented. The voltage stress of all switches in the proposed converter is one quarter of high side voltage, before switches turn on and after turn off. This makes it possible to use MOSFETs with lower voltage and reduced conduction and switching losses to improve the overall efficiency. The conversion ratio of the proposed converter is one fourth of the conventional buck converter in step-down mode and four times higher than conventional boost converter in step up mode. Also, due to charge balance of its blocking capacitors, the proposed converter can share equal currents between two interleaved modules without using any extra current-sharing control method. Another advantage of the proposed converter is its low current ripple due to interleaved structure. The features, operating principles, and analysis of the proposed bidirectional converter are presented. The validity of theoretical analysis is confirmed by the simulation results of 400v-24v converter.