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 softswitching 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 softswitching 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.