Novel Phase-Shift Control Technique for Full-Bridge Converter to Reduce Thermal Imbalance Under Light-Load Condition

A new phase-shift control technique for the phase-shift full-bridge converter is proposed to reduce thermal imbalance of power devices. For the full-bridge converter with phase-shift control, zero-voltage switching (ZVS) can be realized. However, the power devices for the leading leg are with higher thermal temperature since the related current to achieve ZVS is much higher than that for the lagging leg. The proposed new phase-shift control technique is to swap the leading leg and the lagging leg with each other by either alternating control, temperature feedback, or pseudo random method. Experimental results derived from a digital signal processor-controlled full-bridge converter are presented for confirmation. It will be shown that thermal balance among power devices can be achieved, thereby confirming the effectiveness of the proposed control technique.