6.5 kV Si/SiC hybrid power module: An ideal next step?

Abstract

Silicon carbide (SiC) power switches such as JFET or MOSFET have demonstrated their superior advantages over silicon (Si) power devices such as IGBT, especially in terms of significantly reduced switching losses. A major issue facing large scale adoption of SiC power devices is still the much higher cost. This paper proposes that Si/SiC hybrid power module (HPM) should be a natural next step moving forward for high voltage applications to address the cost issue. In the proposed Si/SiC HPM, a SiC JFET is connected in parallel with Si IGBT to combine the advantages of both IGBT and JFET. A 6.5 kV HPM is developed based on Si IGBT and SiC JFET as an example to demonstrate its superior cost/performance. The switching loss can be reduced by more than 70% at a cost of about 70% higher compared to Si IGBT. This work is especially essential for high voltage applications such as medium voltage motor drive, FACTS and HVDC systems.