A Health Monitoring Framework for IGBT Power Modules

Abstract:
A health monitoring framework which enables the detection of wire-bond lift-offs and thermal degradation due to solder fatigue in IGBT power modules is presented in this paper. The framework is applied to power converters during their normal operation and makes use of online measurements of the on-state voltage VCE(ON) and gate threshold voltage Vth to estimate the junction temperature TJ and to monitor the health state of IGBT modules. The online measurements obtained from the monitored IGBT module are compared to reference models (electrical and thermal) which characterize the module in its original state in order to generate a residual. This residual enables the detection of power module degradation by solder fatigue or wire-bonds lift-off. It isolates the effects of degradation from the effects of operating conditions which can mask the impact of module degradation on the measurements. The framework is verified experimentally through power cycling an IGBT module which is at the same time used in a full bridge inverter where the framework is implemented.