A Novel Soft-Switching Full-Bridge Converter With a Combination of a Secondary Switch and a Nondissipative Snubber.

In this paper, a novel soft-switching full-bridge converter with an additional secondary switch and a nondissipative energy recovery snubber is proposed. Thanks to the combination of an active switch and the capacitor—diode–diode snubber employed at the secondary side of the converter, the proposed converter can achieve zero-voltage zero-current switching for all of the primary switches and rectifier diodes over the entire load range. As a result, the rectifier diodes have no reverse-recovery problem and their ringing voltage is clamped. In addition, since no phase shift is used for the gate signals of the primary-side switches, the converter control can be implemented easily and it has no circulating current inherently. The converter exhibits a significant improvement in terms of efficiency, especially under light-load conditions, which is difficult to achieve with conventional phase-shift full-bridge converters. A 3-kW prototype circuit is implemented to verify the superior performance of the proposed converter. [ABSTRACT FROM AUTHOR]