Power cycling method of power semiconductor devices based on mission profiles

With the wide application of power semiconductor devices in severe working conditions, the reliability and lifetime estimation of power semiconductor devices have become the research hotspot. Power cycling test is a significant method to study the reliability issues. This paper first analyzes the existing methods and then proposes a new power cycling method which considers not only realistic electrical conditions but also the thermal stress from different regions. Firstly, rainflow algorithm is used to extract the temperature cycles with large amplitude. Next, the junction temperature cycles and case temperature cycles are matched using integer programming algorithm and modified by means of equivalent substitution. At the same time, a method to control the case temperature and the junction temperature simultaneously is proposed. Afterwards, modified rainflow reconstruction algorithm is used to combine these matched cycles to temperature arrays. Finally, test load profile is formed. An electric vehicle motor drive system based on the Worldwide Harmonized Light Vehicle Test Procedure mission profile is used to verify the proposed method. This method can simultaneously stress the bonding wire and the solder layer, which provides a new way to access the reliability of power devices in real application.