A Novel SiC MOSFET Module for High-power Soft-switching Converter

Fast switching characteristic of SiC MOSFET requires the packaging with low stray inductance. SiC MOSFET chips are used in parallel to extend its rated power, so the current balance must be considered in power module design. To push the switching frequency, soft-switching technique can be introduced to reduce the switching loss. For a soft-switching topology with auxiliary switch, the longer commutation loop makes a higher requirement for low stray inductance design. This paper proposes a SiC MOSFET module for high-power soft-switching converter with auxiliary switch. The low stray inductance is realized by the second layer DBC, internal busbars and small size decoupling capacitors. The stray inductance is extracted to be no more than 7.4 nH in a longer commutation loop by Q3D extractor. At the same time, the current balance among paralleled chips and the thermal stress of the chips are studied.