An Electromagnetic Voiceprint Monitoring Method for Early Degradation Evaluation of IGBT Devices

Monitoring and evaluating the aging state of power semiconductor devices is crucial for the reliability of power electronic converters. Existing methods exhibit low sensitivity and struggle to quantify the early degradation of the solder layer in power devices. During switching transients, power semiconductor devices emit electromagnetic voiceprint (EMVP) signals containing aging information, which can be captured by acoustic emission (AE) sensors. However, the impact of power electronic device degradation on the measured EMVP signals has not been thoroughly investigated. This study investigates IGBT devices and employs a finite element model to simulate EMVP signals under different solder layer void ratios. The results reveal that the energy accumulation curve can serve as an effective indicator of device aging. To validate this finding experimentally, an AE sensor was used to measure EMVP signals during the turn-off transient of IGBT devices. The measurements indicate that as the number of thermal cycling aging cycles increases, the maximum accumulated EMVP energy exhibits a linear growth trend. Compared to conventional aging characterization methods, such as conduction voltage and thermal resistance, the EMVP method demonstrates significantly higher sensitivity to early-stage minor degradation. These findings highlight the potential of the EMVP method for accurate aging state monitoring and characterization of power electronic devices.