A New Transient Thermal Impedance Model for Estimating the Dynamic Junction Temperature of IGBT Modules

Inhalt:
Insulated Gate Bipolar Transistors (IGBTs) are the key component and have been widely used in power electronic systems. The transient junction temperature within the IGBT module is of vital importance for thermal protection and lifetime estimation of a power converter system. This paper proposes a new transient thermal impedance model from IGBT junction to the built-in NTC thermistor Zth,jntc to estimate the dynamic junction temperature of the IGBT. This model is generated using the transient thermal impedance Zth,jc given in the IGBT’s datasheet[1] and the temperatures of baseplate(Case) and NTC thermistor of the IGBT module by experimental measurement. By using the Zth,jntc the necessity of doing a direct measurement of Tj with a high effort high speed data acquisition system is avoided. A case study of a wind power converter is taken as an example to investigate the effectiveness of this new transient thermal impedance model in estimating the dynamic junction temperature of the IGBT.