Analysis of High-Speed PCB With SiC Devices by Investigating Turn-Off Overvoltage and Interconnection Inductance Influence

Silicon (Si) carbide (SiC)-based power switching devices provide significant performance improvements compared to conventional Si devices. The superior characteristics enable considerable loss, size, and weight reduction of power converters in the powertrain of hybrid/electric vehicles. However, the fast switching capability of SiC devices renders them more vulnerable to parasitic inductances in the circuit. The purpose of this paper is to analyze the impact of interconnection inductances to overvoltage during turn-off transient of SiC devices. To understand the switching behavior of the SiC devices, the ringing and overshoots of the voltage caused by the device capacitance and interconnection inductances are considered. Parametric studies are conducted to compare the influences of printed circuit board (PCB) and packaging inductances on the peak turn-off overvoltage under various operating conditions. A prototype half-bridge buck converter with SiC MOSFETs is constructed for the experiments. Experimental results are shown to validate the simulation results.