In-situ monitoring of bond wires in IGBT modules via maximum turn-on voltage of auxiliary emitter

This paper presents a novel in-situ monitoring approach for assessing bond wire aging in IGBT modules, utilizing the maximum turn-on voltage of auxiliary emitter ( V eE-max ) as an aging-sensitive indicator. Initially, based on the turn-on characteristics of IGBT module and equivalent circuit model, this paper systematically analyzes the physical origin and evolution mechanism of V eE-max in relation to bond wire aging. To facilitate real-time measurement, a dedicated peak monitoring circuit is designed and implemented. Then, the feasibility of the proposed method is verified using a double-pulse test circuit, and the effects of operating conditions such as bus voltage, gate resistance, load current and junction temperature are discussed. Experimental results demonstrate that V eE-max exhibits high sensitivity to bond wire aging, with a measured variation of approximately 1.795 V per wire and is not affected by junction temperature and load current, validating its effectiveness as a condition monitoring parameter.