Online condition monitoring of IGBT modules using gate-charge identification

Power converters have been widely used in safety-critical applications, such as marine, aerospace, electric vehicles, and renewable energy, which require much more stringent reliability performance than most industrial applications. Most of these power converters use an insulated gate bipolar transistor as switching devices because of their high voltage and high current capabilities. Reliability of a power converter is mainly verbalized by the failure rate of power modules. Therefore, condition monitoring of IGBT module is crucial to give early sign of device degradations in a power converter. This paper presents a method for detecting degradations or an early failure in the IGBT module by identifying the dynamic change in the gate-charge. An ageing setup using a power cycling machine has been done to trigger degradation and failures in several IGBT samples. The results from the accelerated ageing test indicate that the gate-charge of the IGBTs increases with accelerated ageing over the time period.