Comparative Evaluation of 6kV Si and SiC Power Devices for Medium Voltage Power Flectronics Applications

In order to better assist researchers to select the appropriate power device for medium voltage power electronics applications, this paper presents a comparative evaluation on three typical 6kV level Si and SiC power devices, including 6.5kV/25A Si IGBT from ABB, 6.5kV/15A normally off SiC JFET from USCi and a FREEDM System Center developed 6kV/26A SiC series-connected JFET. The 6.5kV Si IGBT and 6.5kV SiC JFET are packaged in the same module to minimize the effect of different parasitic inductance on the comparison. The 6kV SiC series-connected JFET is developed based on one 1.2kV SiC MOSFET from Cree and four 1.2kV SiC JFETs from Infineon, in this paper, named FREEDM Super-Cascode. A short introduction on the three selected devices are first given, then their forward conduction and switching performances are compared. Also, some additional features are discussed and compared, including the device size, cost, gate driver circuit complexity.