Comparison of a state of the art Si IGBT and next generation fast switching devices in a 4 kW boost converter

Abstract

This paper gives a comprehensive comparison of two promising silicon carbide (SiC) switching devices, i.e. normally-off SiC MOSFET and a normally-on SiC JFET, as alternatives to a conventional state of the art Si IGBT. The comparison uses datasheet information to determine conduction losses, switching transition measurements for switching loss calculations and electrical power measurements in a boost converter. Using SiC switching devices, switching energies can be reduced by almost 70% and the forward voltages of such devices are much lower compared to the IGBT which then reduce the conduction losses. This reduction in semiconductor losses can increase overall converter efficiencies up to 0.4% at 20kHz or enable high frequency operation up to 100 kHz which then reduces the size and weight of the inductor by more than 75% while still achieving efficiencies over 98.3 %.