MHz-Driven Snubberless Soft-Switching Current-Fed Multiresonant DC-DC Converter

Abstract

A new multiresonant step-up dc-dc converter is proposed in this article, which is suitable for obtaining a high dc-dc voltage ratio with minimizing the counts of active and passive components. The proposed dc-dc converter features the snubberless zero current soft-switching (ZCS) commutation with megahertz (MHz) high-frequency driving of galliumnitride-high electron mobility transistor-based two-phase class-E inverters by adopting quasi resonance and dual parallel load resonance; multiresonant circuitry. The circuit configuration and operation principle are described together with the theory of switch-mode transitions and steady-state power transfer. A frequency-domain analysis is provided on the basis of the equivalent circuit, and the design guideline of multiresonant tanks is provided in details. The essential performances of the proposed dc-dc converter are demonstrated by experiment of a rm 1-rm 2MHz / rm 120W prototype; ZCS operations are confirmed over the wide range of load variations (rm 40%-rm 100%) with maximum efficiency rm 91.3% at rm 86.5% load, electro magnetic interference noise reduction rm 29%-rm 79% as compared to hard switching, and the voltage ratio 1.5 times higher than the nonmultiresonant topology, and less than rm 1% low-current ripple factor in the dc inductor.