Transient electro-thermal characterisation at systemlevel for an Easypack-IGBT-Module – Reduced order modelling (ROM) and junction temperature evaluation based on the onstate resistance

This paper presents an approach for the creation of SPICE behavioral models for an IGBT and the reverse diode on a datasheet basis which explicitly describes the transient electro-thermal behavior with a closed function expression using the example of the Infineon FS25R12W1T7 IGBT module. The rapid convergence achieved in this way results in considerably shorter calculation times for an overall simulation at system level compared to an IGBT model consisting of several components (MOSFET, BJT). The validation of the simulation results is carried out in a drive application in order to obtain realistic conditions. The applied method for junction temperature estimation is based on a thermosensitive electrical parameter (TSEP) and extends the online VCEsat(T) measurement method. The onstate resistance is used as the TSEP, which on the one hand leads to a universal measurement method, but on the one hand also to a nonlinearity between temperature and TSEP on the other – Ron(T, VGE, IC). With the help of an algorithm, that has stored the calibration data in functions and applies an optimized multi-stage curve fitting, the back calculation and thus the determination of the junction temperature is made possible.