A novel full-bridge DC-DC converter for battery charging using secondary-side control combines soft switching over the full load range and low magnetics requirement

A novel full-bridge DC-DC configuration with a tapped transformer and secondary side control is proposed. It achieves zero-voltage switching for the primary side switches and zero-current switching for the secondary side switches, under all operating conditions. The conduction losses are significantly lower than those in the conventional soft-switching DC-DC converters. Due to superior filter waveforms, the filter requirements, both at the input and at the output, are significantly reduced. The features of the proposed converter are compared with those for the conventional phase-modulated full-bridge DC-DC converters. The proposed configuration is ideally suited for the AC-DC stage of high-power battery-charging applications with a power-factor-corrected preregulator. Analytical and experimental results on a 500 W/100 kHz prototype are presented.