Control optimization of a dual resonant converter for 15–75V input voltage application

This article presents a modified control strategy for a large input voltage range in an active-clamp soft switching converter. This control strategy is based on frequency modulation and allows a soft switching of all semiconductor devices on a large input voltage range. This frequency modulation also minimizes transformer loss without losing soft switching both on primary and secondary side of the converter. The proposed control strategy was implemented on a 30W prototype with a switching frequency up to 215kHz. The prototype is soft switching on an input voltage range between 15V and 75V, confirming the benefits of the presented control strategy with efficiency above 90% on a 28-63V range.