System Study of SiC MOSFET and Si IGBT Power Module Performance using a Bidirectional Buck-Boost Converter as Evaluation Platform

This paper presents the results of a system study comparing a SiC MOSFET and a Si IGBT power module on a DC/DC power conversion system level. The target of this study is the evaluation of a reduced cooling effort as well as the reduction of inductor sizes by the use of high efficient SiC switches. Therefore a conversion performance target have been defined which have to be fulfilled by the SiC and Si based power conversion system. Lower static and dynamic power losses of the SiC MOSFET based system allow a much higher switching frequency as the Si IGBT based system. As a result magnetics and capacitors of the SiC MOSFET module based system a much smaller and cheaper as for the Si IGBT system. A further reduction of the conversion losses could be achieved by the use of synchronous rectification enabled by the integrated body diodes of the SiC MOSFETs used in this work. The results of this study show the potential of SiC MOSFET modules on a system level in terms of power density, conversion performance and the reduction of system costs.