Improved zero-voltage-switching pulse width modulation full bridge converter with self-regulating auxiliary current

An improved zero-voltage-switching (ZVS) phase-shift full-bridge converter with self-regulating auxiliary current is proposed. ZVS of lagging-leg switches can be achieved in whole conversion range because of the introduced active auxiliary circuit. Meanwhile, the auxiliary circuit that features simple control of the auxiliary switches has no effect on the main power transferring path and the auxiliary energy stored for ZVS of lagging-leg can be regulated by the load current without significantly increasing conduction loss over the entire load range. The operation principle of the proposed converter is discussed in detail and further simplification of the proposed topology is suggested. The design method of key parameters is carefully depicted. Finally, the operation and performance of the proposed converter are verified on a 1 kW/54 V, 100 kHz prototype.