AN EXPERIMENTAL COMPARISON OF THERMAL MODELLING TECHNIQUES FOR IGBT MODULES IN ELECTRICAL DRIVETRAINS

Abstract

Due to a strong drive towards a higher power density of electrical drivetrains and the impact of cooling on their reliability, the thermal characterisation and monitoring of these systems is gaining importance. The power electronic devices driving the electrical motor in this system are often integrated within one power module, complicating temperature measurements and monitoring of the semiconductor devices. Therefore, accurate thermal models of these modules are necessary. The main challenge remains to model these thermal properties sufficiently accurate to estimate the device temperatures, while maintaining an evaluation speed fast enough to ensure safe operating temperatures in real-time. Furthermore, in the search for enhanced cooling methods, it may be interesting to compare cooling designs using simulations before or instead of experiments. To this end, this paper develops and compares the accuracy of a 3D grey-box Lumped Parameter Model of an IGBT module coupled with an interchangeable cooling model with two 1D Lumped Parameter Models. The 3D model is based on a Finite Element representation, while the 1D models are based solely on datasheet information. The different model types are discussed and compared regarding their accuracy using simulation and experimental results.