D $v$ /D $t$ -Control Methods for the SiC JFET/Si MOSFET Cascode

Switching devices based on SiC offer outstanding performance with respect to operating frequency, junction temperature, and conduction losses enabling significant improvement of the performance of converter systems. There, the cascode consisting of a MOSFET and a JFET has additionally the advantage of being a normally off device and offering a simple control via the gate of the MOSFET. Without dv /dt-control, however, the transients for hard commutation reach values of up to 45kV/μs, which could lead to electromagnetic interference problems. Especially in drive systems, problems could occur, which are related to earth currents (bearing currents) due to parasitic capacitances. Therefore, new dv/d t-control methods for the SiC JFET/Si MOSFET cascode as well as measurement results are presented in this paper. Based on this new concepts, the outstanding performance of the SiC devices can be fully utilized without impairing electromagnetic compatibility.