Simultaneous online estimation of junction temperature and current of IGBTs using emitter-auxiliary emitter parasitic inductance

A novel method is presented for online estimation of the junction temperature (Tj) of semiconductor chips in IGBT modules, based on the voltage drop (VEE') across the parasitic inductor that exists between the main emitter (E) and auxiliary emitter (E) terminals. The peak amplitude of the voltage drop (VEE') was found to depend on the junction temperature at a known current and DC link voltage. Also, the collector current can be estimated simultaneously, by integrating VEE' without the use of any additional sensors. Measurement circuits were implemented to estimate Tj and the current, and their results are discussed. The results of these measurement circuits when implemented in a real power electronic (PE) converter to estimate Tj and current in real time are also presented. This method opens up a full set of new opportunities for engineers and designers to better understand the behavior and performance of high power modules in real PE applications.