Improved Lifetime Prediction Model of IGBT Module Considering Aging Effect of Solder Layer

The insulated gate bipolar transistor (IGBT) module is the core component in a converter, and its aging failure monitoring and evaluation is of great significance to the safe and reliable operation of the system. In the physical lifetime model using an energy-based method, the fixed deformation energy in a single cycle is usually used to predict the lifetime, ignoring the influence of the module aging process on the deformation energy. In this paper, a lifetime prediction model of power modules which considers the aging effect of the solder layer is proposed. Firstly, the finite element method and Clech algorithm are used to form the stress-strain hysteresis loop of the solder joint under cyclic thermal load, and the area of the hysteresis loop is calculated to represent the magnitude of the deformation energy in a single cycle; secondly, the influence of aging process on deformation energy is analyzed. And the thermal resistance degradation is taken into account to improve the traditional lifetime model; finally, the differences between this model and the existing commonly used models are compared, and the accuracy of the model proposed in this paper is verified.

I. Introduction

In recent years, with the rapid growth of the installed capacity of renewable energy, the reliability of the converter system has attracted a lot of attention. As the core component of the converter, the failure rate of insulated gate bipolar transistor (IGBT) exceeds 30% [1], [2], which seriously threatens the safe and reliable operation of the entire system. Carrying out condition monitoring and lifetime prediction for IGBT power modules can make maintenance plans in time, effectively reducing the system outage time caused by failure of converter, which is crucial to improving the reliability of the system.