New active snubber cell for high power isolated PWM DC-DC converters

Abstract

Here, a new active snubber cell for high-power isolated pulse-width-modulated (PWM) DC-DC converters is proposed. All semiconductor power devices in the proposed converters operate with full soft switching under a very wide load range, and they are not exposed to any voltage and current stress. The main switches turn on with zero-voltage transition (ZVT) and turn off with zero-voltage switching (ZVS). The auxiliary switches turn on with zero-current switching (ZCS) and turn off with ZVS. The theoretical analysis and design procedure for the proposed active snubber cell are carried out in detail and are verified with a half-bridge (HB) converter implementation having 20V output voltage, 50 A output current, and 80 kHz switching frequency. The overall efficiency of the HB DC-DC converter is increased from about 83% in the hard switching condition to about 90% thanks to the proposed active snubber cell.