Analysis and Active Mitigation of Fatigue in Power Electronic Inverters

Authors

C. van der Broeck, FEV Europe GmbH

Summary

Thermal cycling is a major cause of degradation within power electronic inverters. It induces strain at the interfaces of materials with different coefficients of thermal expansion. This inevitably leads to fatigue and causes fatal component failures. The strong demand for highly integrated inverters, whose reliability must be guaranteed over a long service life, puts a spotlight on this problem. Thus, next generation power modules require thermal management and control technologies that can intelligently mitigate thermal cycles. To identify key enabling technologies along this path, this paper provides insight into the physical root-cause of thermally induced fatigue. It identifies characteristics in mission profiles and powertrain control that cause the most severe thermal cycling. Finally, it presents methods for active mitigation of thermal cycling.