A Hybrid‐Full‐Bridge Resonant Converter With Reduced RMS Current and Balanced ZVS Range

A hybrid‐full‐bridge resonant converter (HFBRC) to cope with large tank currents is proposed in this article. With the adoption of a dual‐transformer structure, the control variables are extended. Hence, a four‐control‐variable (4CV) modulation scheme is utilized to keep ZVS operation within a desired range. According to the fundamental harmonics approximation (FHA) approach, the steady‐state features, including the tank current and transmission power, are analyzed and derived. In addition, the full‐domain closed‐form optimal solution for minimizing root‐mean‐square (rms) current is obtained using the global optimal condition (GOC) optimization method. With the appropriate ZVS range and minimized rms current operation, the system efficiency is enhanced in buck mode compared with the dual‐bridge series resonant converter (DBSRC). The discussed topology and optimization method are verified by a 400 W prototype.