In renewable energy and grid applications, solder-attached power modules are subject to
fatigue stress cycles of low amplitudes, but the devices will be in service for decades. This
article aims to understand the slow aging process by focusing on the initial defects and their
growth under the stress cycles of concern. A finite-element analysis (FEA) is performed to
obtain the thermomechanical stress distribution around the defects, which is combined with
the solder material's property to give a lifetime model. Effort is made to validate the model by …

Solder-attached IGBT power modules are widely use in renewable energy and smart grid
applications where the thermomechanical stress cycles are relatively low in amplitude but
the service duties of the devices are expected to last for decades. Although the initial defect
voids and cracks in the solder layer are widely recognized as the triggers of initial aging, it is
still necessary to describe and simulate the physical fatigue behavior in their local regions
accurately under low amplitude stress cycling. In order to investigate the growth of the …