A Half-Turn Transformer With Symmetry Magnetic Flux for High-Frequency-Isolated DC/DC Converters

A half-turn transformer with symmetrical magnetic flux is proposed for high-frequency-isolated dc/dc converters. The transformer structure can reduce the minimum number of turns from 1 to 0.5. By adopting a novel winding and circuit configuration, a symmetrical magnetic flux is realized to make full utilization of the ferrite core. A simple EI core, which is easily manufacture and commercially available, can be used to make the half-turn transformer. The operation principles of the transformer are analyzed and simulated. The performance of the transformer is experimentally evaluated on a 750-kHz, 380/12-V, 600-W LLC converter using gallium nitride devices with a peak efficiency of 98%.