Influence of IGBT and Diode Parameters on the Current Sharing and Switching-Waveform Characteristics of Parallel-Connected Power Modules

The parallel connection of IGBT power modules allows flexible power converter designs. However, differences in parameters like forward and threshold voltage ( $\Delta V_{\text{CEsat}} \Delta V_{\mathrm{G}\mathrm{E}(\mathrm{t}\mathrm{h}}$, and $\Delta V_{\mathrm{E}\mathrm{C}})$ between parallel-connected power modules may particularly influence static and dynamic current sharing, and switching characteristics, among several factors. Therefore, when designing converters with parallel-connected power modules, current sharing and switching characteristics of individual power modules must be considered to ensure operation within safe operating area and temperature limits. Derating is to be considered if necessary. Identifying the influential parameters in a parallel-connection, and quantifying their influence on current sharing and switching characteristics, are essential to understand and optimize the amount of derating. This paper first describes the measurement results of ten parallel-connected pairs of 3.3 kV IGBT power modules. Afterwards, the imbalance of switching characteristics (such as switching energy or current amount) is related to power-module parameters, by multiple linear regression. Fanally a methodology for defining the derating ratio for each switching characteristic is described.