A Multilevel, Multimodule DC-DC Converter Architecture For Universal Electric Vehicle (EV) Battery Charging Applications

The paper presents a multi-level, multi-module DC-DC converter architecture intended for universal EV battery charging applications. The converter architecture is centered around a multi-level, multi-primary, single common secondary linear step-up transformer. The multiple primaries are individually fed with high frequency resonant inverters which are stepped up in the secondary side and subsequently rectified by an active bridge to generate DC voltage at the battery load. The proposed converter is capable of generating a wide output voltage of 150-950V at a peak power of 22kW at 97% peak efficiency, while maintaining soft-switching transition for all switches, for the full operating voltage range. A mathematical model aiding in design and selection of converter temporal characteristics for different loading conditions is presented. A scaled down experimental prototype (voltage range of 28V-140V and power range of 0.18kW – 0.6kW) with peak efficiency of 96% is built as a proof of concept.