Characterizing the Switching Behavior of a 1.2 kV mixed SiC JFET and MOSFET Half Bridge

Abstract:
For cost savings and loss reduction in automotive inverters, SiC JFETs are promising devices compared to SiC MOSFETs. For this reason, the switching behavior of JFETs and MOSFETs is investigated and compared with each other. The normally-on behavior of the JFET, which is a disadvantage due to a phase short-circuit while the gate driver supply voltage fails, can be turned into an advantage by mixing each half bridge of a B6 inverter with a normally-off semiconductor. The mixed half bridge configuration allows an active short-circuit case in an automotive inverter, by itself. For this reason, the switching behavior and switching effects in a mixed JFET/MOSFET half bridge are investigated and compared with the uniform half bridges. To complete the switching characterization, a performance calculation is performed using a B6 inverter.