A Method for Individual Switching Energy Extraction in Si/SiC Fusion Switches

Abstract

The Si/SiC Fusion switches have the potential to bridge the cost-efficiency gap between IGBT and SiC MOSFETbased inverter solutions in automotive traction inverters. By shorting the SiC MOSFET and IGBT gates, a new three-terminal device is formed. The feasibility of this single gate drive feature has already been demonstrated in previous studies. To accurately calculate device temperatures and thermal stress distribution, knowledge of the switching energy distribution on individual dies is essential. However, measuring the current share rates between the SiC MOSFET and IGBT in compact power modules poses significant challenges, leading to impractical experimental setups that are modified from the final application and limited to maximum testable temperatures of typically $125^{\circ} \mathrm{C}$. To overcome this issue, a new method has been developed that utilizes only the sum current measurement and standard voltage probes, similar to a conventional double-pulse test bench. This method extracts the individual device switching loss energies based on the characteristic curve of the sum current. The method will be introduced in detail and compared to measured energy share rates using device individual current probing. Due to its high reproducibility and good correlation with measurements, the new method provides a seamless path for characterizing Si/SiC Fusion switches in various power module packages and can be used up to the limits of device temperatures of 200°C or more.