Aging Monitoring of Bond Wires Based on EMR Signal Spectrum Characteristics for IGBT Module

Bond wires aging is one of the most common failure modes of insulated gate bipolar transistor (IGBT) module. Real-time monitoring of bond wires status is an important guarantee for the stable operation of power electronics system. In this paper, a method of monitoring the aging state of bond wires in IGBT module based on the spectrum characteristics of electromagnetic radiation (EMR) signature is proposed. Firstly, the turn-off process of IGBT module is analyzed, and the behavior model of IGBT module in the stage of rapid current change is established, which shows that EMR interference in buck converter mainly occurs during the turn-off process of IGBT module. Secondly, the relationship between the aging degree of bond wires and differential mode (DM) interference signal is deduced. Thirdly, the IGBT module is equivalent to a magnetic dipole, which proves that the change of DM interference signal will cause the change of EMR signal, thus demonstrating the feasibility of using EMR signal to monitor bond wires aging. Finally, a buck converter composed of IGBT module is used as the equipment to be tested. The EMR signal is extracted by the near-field probe, and the EMR signal spectrum is used to monitor the aging degree of the bond wires. The experimental results show that with the deepening of the aging degree of bond wires, the spectrum amplitude of EMR signal increases.