Analytical simulation and experimental comparison of the losses in resonant DC/DC converter with Si and SiC switches

High efficiency is among the most important targets in power electronic converters. A possible approach to obtain this goal is the usage of better switches. This paper is focused at the study and comparison of SiC and Si power MOSFETS in soft switching resonant DC/DC converter. The latter converter being a part of light battery charger used in ultra-light electric vehicles is realized and investigated. The losses in the power switches are compared mathematically, with simulations and experimental verification. Two types of transistors are considered. First traditional state of the art Si-technology using a FREDFET (fast recovery diode MOSFET) and it is compared with what the SiC technology offers, using a fast Schottky antiparallel diode. As an example a 1500 W series resonance converter with input voltage of 400 V and output voltage of 100 V is used. The latter voltage permitting the use of Schottky diodes at the secondary side. The losses in both converters are compared via calorimetic measurements to avoid accuracy problems as in loss measurements with an oscilloscope for example.