Analysis of Influence Parameters of Stress Wave at the Turn-Off Moment in IGBT Device Based on Differential AE Sensor

Acoustic emission (AE) is a fast, non-destructive and real-time detection method widely applied in the power industry. It has been reported that AE has potential application value in the condition monitoring of insulated gate bipolar transistor (IGBT). The stress wave is released at the moment when the IGBT is turned on and off, which can be measured by the AE sensor. However, due to interference from the changing electric field on the AE sensor, the pulse signal is frequently intermingled into the stress wave during measurement, making stress wave extraction difficult. In this paper, a novel stress wave extraction method of based on the differential AE sensor is proposed, which can decouple the pulse interference mixed in the stress wave signal from IGBT, and the effectiveness of the method is demonstrated through experiment. Furthermore, extraction experiments of stress wave from IGBT under the conditions of various gate turn-off resistance (R_off), bus voltage (V_dc), and turn-off current (I_off) are carried out. By testing two models of IGBT from different manufacturers, similar conclusions can be obtained that the amplitude, peak-peak value and signal energy of IGBT’s stress wave are all strongly related toR_off,V_dcandI_off. In addition, the source mechanism of the stress wave from IGBT is also discussed through the analysis of the relationship between turn-off loss (E_off) of the IGBT andR_off,V_dcandI_off.