Extending the ZVS Range of Phase-Shifted Full-Bridge DC-DC Converters with a Variable Inductor

The objective of this study is to introduce a novel method for extending the soft-switching range of Phase-Shifted Full-Bridge DC-DC converters. Although these converters are renowned for their high efficiency, they face challenges in maintaining soft switching across a wide load range. The proposed approach incorporates a variable inductor, controlled by a low-power DC excitation, to reduce the current on power switches during mid- to full-load conditions and ensure adequate current to maintain soft switching under light-load conditions. Both the practical implementation of the variable inductor and the simulation of the converter confirm the feasibility of the proposed design.