Enabling Short-Term Over-current Capability of SiC Devices using Microchannel Cooling

Fault clearance time in the power system with renewables generally varies from 0.5-10 cycles (10-667 ms for 50 Hz). Power electronic converters should be able to provide an increased current without exceeding the thermal limits during faults. Accordingly, the heat generated in the semiconductor chip during over-current (OCs) should be removed from the chip as soon as it is generated. In this paper, microchannel (MC) cooling has been investigated through COMSOL simulations for OCs with SiC MOSFETs. The upper limit of the chip temperature has been assumed to be 250 °C as SiC devices do not fail in this temperature range. The duration of OCs is from a few tens of milliseconds to a few seconds. It is concluded that MC cooling has the potential to increase the duration of OC without reaching the assumed upper limit of the temperature.