A ZVZCS full-bridge DC/DC converter with a passive auxiliary circuit in the primary side

摘要

A ZVZCS full-bridge converter with phase-shift control is proposed in this paper. The ZCS condition of the lagging-leg is achieved by using a simple auxiliary circuit, which resets the primary-side current during the freewheeling stage. The ZVZCS operation can reduce the switching losses and the circulating conduction losses. The auxiliary circuit is composed of only a small transformer and two clamp diodes, which is inserted in the primary side of the main transformer. There are neither additional active switches nor resistors in the resetting circuit. A prototype with 1kW operating at 50kHz is built in the lab to confirm the effectiveness of the presented converter.