Aging Monitoring of Bond Wires Based on Differential Mode Conducted Interference Spectrum for IGBT Module

This article presents a method for monitoring the aging of insulate gate bipolar transistor (IGBT) module bond wires based on the spectrum characteristics of differential mode (DM) interference signals. The buck converter composed of IGBT modules is used as the device under test. The path of DM current in buck converter passes through the IGBT module, so the DM current is more suitable for monitoring the status of the module. The DM electromagnetic interference (EMI) in buck converter is mainly generated by the rapid decrease of the collector current, and the aging degree of bond wires is directly related to the DM EMI signal. The aging degree of bond wires inside IGBT module is monitored by the peak value of DM EMI signal in low frequency band. The experimental results show that the DM EMI amplitude of buck converter with aging IGBT module is larger than that of the buck converter with healthy IGBT module. The main advantage of the method proposed in this article is that it is independent of temperature and can realize the on-line accurate monitoring of the aging of the bond wires inside the IGBT module through the current probe under the actual working conditions.