The accuracy of the lifetime calculation approach of IGBT power modules used in hybrid-electric power trains suffers greatly from\nthe inaccurate knowledge of application typical load-profiles. To verify the theoretical load-profiles with data from the field this\npaper presents a concept to record all junction temperature cycles of an IGBTpower module during its operation in a test vehicle. For\nthis purpose the IGBT junction temperature is measured with a modified gate driver that determines the temperature sensitive IGBT\ninternal gate resistor by superimposing the negative gate voltage with a high-frequency identification signal. An integrated control\nunit manages the TJ measurement during the regular switching operation, the exchange of data with the system controller, and\nthe automatic calibration of the sensor system. To calculate and store temperature cycles on a micro controller an online Rain flow\ncounting algorithm was developed.The special feature of this algorithm is a very accurate extraction of lifetime relevant information\nwith a significantly reduced calculation and storage effort. Until now the recording concept could be realized and tested within a\nlaboratory voltage source inverter. Currently the IGBT driver with integrated junction temperature measurement and the online\ncycle recording algorithm is integrated in the voltage source inverter of first test vehicles. Such research will provide representative\nload-profiles to verify and optimize the theoretical load-profiles used in today�s lifetime calculation.
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