Gate–Emitter Pre-threshold Voltage as a Health-Sensitive Parameter for IGBT Chip Failure Monitoring in High-Voltage Multichip IGBT Power Modules

This paper proposes a novel health-sensitive parameter, called the gate-emitter pre-threshold voltage VGE(pre-th), for detecting IGBT chip failures in multichip IGBT power modules. The proposed method has been applied in an IGBT gate driver and measures the VGE at a fixed time instant of the VGE transient before the threshold voltage occurs. To validate the proposed method, theoretical analysis and practical results for a 16-chip IGBT power module are presented in the paper. The results show a 500 mV average shift in the measured VGE(pre-th) for each IGBT chip failure.