Impact of the Different Parasitic Inductances on the Switching Behavior of SiC MOSFETs

Abstract

This paper experimentally investigates into the effects of parasitic inductances on the switching performance of a SiC MOSFET half bridge. As the switching dynamics of wide-bandgap power semiconductors are by magnitudes larger compared to silicon devices, the parasitic elements in the switching cell become increasingly important, as they limit the current and voltage slopes and cause oscillations. A thorough understanding of those effects is necessary for the design of highly efficient and integrated next-generation power electronic converters. An implementation method to realize cheap and well-reproducible variable inductors in the nanohenry range is presented. Furthermore, a test PCB equipped with SiC MOS-FETs is built and double pulse experiments are carried out under the variation of all relevant inductances in the switching cell. The results are analyzed with respect to the switching performance and differences between the switching transients of Si and SiC devices are demonstrated and explained with respect to the parasitic elements.