A Novel Three-Pulse Equivalent Power Loss Profile for Simplified Thermal Estimation

One of the key challenges for long-term reliability analysis of power electronic converters is to quickly estimate extensive junction temperature cycles of power semiconductor devices while fulfilling an accepted accuracy. To address this challenge, this article proposes a novel three-pulse equivalent power loss profile. By contrast to the conventional methods of dividing the power loss equally, this article discretizes the power loss profile based on the identified occurrences of maximum and minimum junction temperatures (i.e., thermal characteristics). This proposed model decouples the conventional conflict between the thermal estimation accuracy and computational burdens. And it has the advantages of improving accuracy in terms of the maximum and minimum junction temperatures, and power-on time of thermal profiles, which are majorly concerned by today's lifetime models of power semiconductors. Moreover, the proposed method also helps to reduce computational burdens. The relevant variables of the thermal modeling methods are investigated. Finally, the effectiveness of the proposed method is verified through simulation and experiments, and the impact of its thermal estimation advantages on lifetime evaluation is analyzed further.