Evaluation of a SiC dc/dc converter for plug-in hybrid-electric-vehicle at high inlet-coolant temperature

An all-SiC 0.25 MHz 5 kW multiphase dc/dc bidirectional boost converter, operating with a 105 degrees C inlet coolant temperature is described that serves as a charger for the intermediate high-voltage energy storage device (e. g. ultracapacitor) in a plug-in hybrid-electric vehicle (PHEV). The primary focus of this study is to report the high-temperature efficiency of the normally on SiC VJFET and SiC Schottky-based robust converter and identify the key loss components. Further, comparison of efficiencies for hard-switching, soft-switching and dynamic-power-management-based hard-switching conditions are provided that indicate efficacy as well as the limitation of the present-generation of the SiC VJFETs.