Evaluation of on-state voltage VCE(ON) and threshold voltage Vth for real-time health monitoring of IGBT power modules

This paper investigates by experiment and simulation the use of the real-time measurements of on-state voltage V_CE(ON) and threshold voltage V_th for real-time health monitoring of IGBT power modules. A study of the dependencies of each parameter on temperature, wear-out mechanisms and operating conditions is presented. Online measurement circuits are developed to obtain these two parameters during the normal operation of power converters. Junction temperature estimation for health monitoring is implemented using V_th which is a thermo-sensitive electrical parameter. The data of V_CE(ON), V_th and T_J are combined in a residual-based health monitoring framework which allows the discrimination between two dominant failure mechanisms of power modules: wire-bond lift-off and solder fatigue.