Instrumentation Requirements for Fast 130+ V/ns Switching of 1700 V, 35 mOmega SiC MOSFETs

Abstract:
This paper demonstrates the benefits, downsides, and instrumentation requirements of switching 1.7 kV, 35 mOmega SiC MOSFETs at 130+ V/ns, beyond the speed used by the device manufacturer for datasheet characterisation. Experimental results are obtained in a 1200 V, 50 A bridge leg, and comparisons are made between passive voltage probes, optically isolated differential probes, shunt current measurement, Rogowski coils, and Infinity Sensors. At 130 V/ns, a 24% improvement over the datasheet characterised switching loss is found, however the limitations of Rogowski coils and passive probes become significant. The methods demonstrated should permit design engineers to explore switching speed and efficiency limitations in their applications.