Analysis and Design of a Current-fed Two Inductor Bi-directional DC/DC Converter using Resonance for a Wide Voltage Range

Abstract

In this paper, a current-fed two-inductor bi-directional DC/DC converter using resonance (CF-TIBCR) and its design method are proposed. The CF-TIBCR has characteristics of low current ripple and a high current rating because of two separated inductors. Also, it achieves zero voltage switching for all switches and zero current switching for switches of a low voltage stage by using the resonant tank. Besides, a voltage spike problem in conventional current-fed converters is solved without the need for an additional snubber or clamping circuits. As a result, the CF-TIBCR features high step-up and high efficiency. Since the proposed converter has difficulty achieving the soft switching condition when the converter requires the low voltage transfer ratio, a method that varies the number of resonant cycles is adopted to extend the output voltage range with satisfying the soft switching condition. The principles of the operation characteristics are presented with a theoretical analysis, and the proposed converter is verified through results of an experiment using a laboratory prototype.