An Online Bond-Wires Lift-off Monitoring Method for IGBT Without Effect of Operation Conditions

Bond-wires failure is one of the most prevalent failure modes in insulated gate bipolar transistors (IGBTs). This article proposes using the maximumdig/dtas a health-sensitive parameter (HSP) to enable non-invasive online monitoring of bond wire lift-off conditions in IGBTs. Firstly, thedig/dtis studied by differentiating the gate current, its expression and characteristics are analysed. It is discussed that the maximumdig/dtas the HSP is not affected by bus voltage, temperature, and load current, et al. And then, a sampling circuit of the maximumdig/dthas been designed with a current transformer in gate-driver circuit. And the sampling circuit can convert the maximumdig/dtinto a stable voltage signal. Finally, the inverter experimental platform is developed to verify the correctness of theoretical analysis. Compared with existing methods, experimental results show that the proposed method is more effective in the converter-level system applications and the sampling circuit of proposed method is much simpler. It indicates that the proposed method is a promising HSP method for online monitoring the IGBT bond-wires lift-off without effect of operation conditions.