Efficiency Comparison of Full-Bridge DC-DC Converters for High-Power EV Charging Modules

Abstract

Isolated full-bridge DC-DC converters are being extensively used when power levels of over 100 kWare needed for fast charging of electric vehicles. This paper analyses the efficiencies of two popular unidirectional converter topologies, namely phase-shift full-bridge converter and LLC converter that utilize silicon carbide semiconductors. Efficiencies of the converters at partial load and various input-output voltage levels are evaluated by by simulations in Plexim PLECS. The results show that the designed phase-shift full-bridge converter has higher efficiency than the LLC converter when high boost ratio is required, whereas the LLC converter has higher efficiency near the nominal operating voltages.