New Thermal Balance Control Techniques of Phase-Shift Full-Bridge Converter

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