High voltage Si/SiC hybrid switch: An ideal next step for SiC

Silicon carbide (SiC) power switches such as MOSFET or JFET 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 switch should be a natural next step moving forward for high voltage applications to address the cost issue. In the proposed Si/SiC hybrid switch, a SiC MOSFET is connected in parallel with Si IGBT to combine the advantages of IGBT and MOSFET. This concept can also works well with SiC JFET. A 6.5 kV Si IGBT and SiC MOSFET hybrid switch is developed as an example to demonstrate its superior cost/performance. The switching loss can be reduced by more than 70% at a cost of only 50% higher compared to Si IGBT. This work is especially essential for high voltage applications such as medium voltage motor drive, FACTS and HVDC systems.