Prof. Uwe Scheuermann, Semikron Elektronik
Dirk Malipaard, Fraunhofer IISB
Prof. Martin Pfost, TU Dortmund University
Dr. Evgeny Rudnyi, CADFEM
Dr. Arendt Wintrich, Semikron Elektronik
After a review of the basic theory of heat transfer, the calculation of losses in a voltage source inverter will be explained. For selected stationary operating conditions, the expected device temperatures of the sample converter will be calculated from datasheet values. Application of online tools to facilitate this process will be demonstrated. Participants can chose between FEM simulations with ANSYS™ and equivalent thermal network calculation with LTspice™ to simulate these operating conditions. The results are compared to thermal measurements using thermocouples and an IR camera.
Following a brief summary of the results of the first part, the transient thermal characteristic of the converter is addressed. Details on failure mechanisms, mission profiles and TIM materials will highlight the correlation between thermal characteristic and reliability. The measurement of the system thermal impedance with standard laboratory equipment and the evaluation process will be demonstrated. Reliability testing and the impact of module design on reliability and lifetime will be discussed. Application of simulation tools to analyze the correlation between thermal impedance and reliability and the impact of cooling technologies will conclude the tutorial.