Integration of a measurement circuit to determine junction temperatures of IGBTs in a three-phase converter

Abstract:
In order to realize an overtemperature protection for converter modules, an online determination of the junction temperatures is advisable. By comparing the measured junction temperatures with model based reference values, a condition monitoring of the converter module can be realized. By evaluating the long-term behaviour of the junction temperatures, deteriorated thermal interfaces or wearout can be detected. However, since the junction temperature can not be measured directly in power electronic standard applications, suitable measurement methods have to be defined. In this paper, the system integration of such a measuring concept into a three-phase converter will be described.