Monitoring Chip Branch Failure in Multichip IGBT Modules Based on Gate Charge

The reliability of the multichip insulated gate bipolar transistor (IGBT) modules has been a concern. Condition monitoring is an effective approach to enhance reliability and improve the quality of customer service. This article proposes a method for monitoring the chip branch failure due to bond wires fatigue in the multichip IGBT modules. The idea is based on the cumulative effect of the gate charge deviation when the chip branch fails. By integrating the turn-on gate current of multiple switching cycles, the health state of multichip IGBT modules is characterized by the capacitor voltage as a health-sensitive parameter that can be extracted in the proposed monitoring circuit integrated into the gate driver. The capacitor voltage decreases significantly when the chip branch occurs due to bond wires fatigue. It is stable during sampling and has a strong immunity to junction temperature, collector current, and collector-emitter voltage. Besides, the method is nonintrusive and has the potential for real-time and online monitoring. These characteristics make the method reliable, easy to implement, and convenient for health status identification. The confirmatory experiment is carried out to verify the feasibility of the method.