Influence of Pulse Duration on the Double Linear Damage Accumulation Rule With Power Cycling Test for the Lifetime Prediction in Power Devices

A proper lifetime model is beneficial to the reliability evaluation of power converters. In this article, a lifetime model for solder layer aging of power module is proposed, with thermal resistance growth rate as the characteristic quantity. The focus is on the effect of pulse duration on module lifetime in power cycling test. The increase in thermal resistance of the solder layer is extracted by transforming the transient thermal impedance curve. A double linear damage accumulation model is proposed to describe the initiation and propagation of cracks in the solder layer during the aging process of the module. The effect of different pulse durations on the aging of solder layers is analyzed through finite element simulation and power cycling test results. By comparing with conventional models, the accuracy of the proposed model for lifetime prediction under variable load conditions is demonstrated.