Analysis, Design, and Experimental Results of Novel Snubberless Bidirectional Naturally Clamped ZCS/ZVS Current-Fed Half-Bridge DC/DC Converter for Fuel Cell Vehicles

This paper presents a novel snubberless naturally clamped bidirectional current-fed half-bridge isolated dc/dc converter for fuel cell vehicles (FCVs). The proposed converter achieves zero-current switching (ZCS) of the primary-side active semiconductor devices and zero-voltage switching of the secondary-side active semiconductor devices. It is a potential topology for FCVs, front-end dc/dc power conversion for fuel cell inverters, and energy storage. A proposed secondary-modulation clamps the voltage across the primary-side devices (current fed) naturally and eliminates switch turn-off voltage spike concern with ZCS without any additional circuit. This leads to reduced footprints and lower cost. Voltage across the primary-side current-fed devices is independent of duty cycle like conventional current-fed converters but clamped at a reflected output voltage. Therefore, comparatively low-voltage-rating devices with a low on-state resistance are used, introducing low conduction losses and higher efficiency. Steady-state analysis, operation, design, simulation, and experimental results of the proposed converter are reported in this paper.