Mutual and self-aging effects of power semiconductors on the thermal behaviour of DC-DC boost power converter

A shift from conventional to renewable resources has increased the importance of power exploitation via power converters. In this respect, estimating an accurate useful lifetime of power converters plays a major role for the manufacturers and users. This paper touches the issues related to the self and the mutual degradation effects of the power semiconductors such as IGBT and diode on each other in a conventional DC-DC boost converter. By IGBT and diode aging, junction-case thermal resistance, IGBT collector-emitter voltage and diode forward voltage have been increased leading to thermal operating point changes. These changes have a significant effect on the degradation and the useful lifetime of devices. It is shown that by either IGBT or diode aging due to the thermo-mechanical fatigue, an increase in the IGBT or diode junction temperature has been occurred. The results reveal the importance of mutual- and self-aging effects on the reliability assessment. An experimental validation has been also performed via a prototype setup of 200/400V 3000W DC-DC boost converter.