Soft switching circuit for IGBTs in high-frequency buck converters using saturable inductors

A PWM DC/DC buck converter with a soft-switching network using saturable inductors is presented. The circuit has soft-switching transition over a wide load range, with low electromagnetic emission and high efficiency. This paper presents its operating principle together with the relations for complete converter design. The design was applied to an IGBT prototype with a 300 V input voltage and a 800 W output power with a switching frequency of 80 kHz. Experimental results on the laboratory prototype showed good agreement with theoretical predictions.