A Health Monitoring Method for Bond Wires in IGBT Modules Based on Voltage Ringing Characteristics

Bond wire failure is a common failure that seriously affects the reliability of insulated-gate bipolar transistor (IGBT) modules. Real-time health monitoring for bond wires is very important to avoid catastrophic failures. In this article, we introduce a new health monitoring method for bond wires in IGBT modules based on the voltage ringing characteristics. We applied a double pulse circuit to generate voltage ringing in IGBTs and freewheeling diodes (FWDs) during turn off and reverse recovery phases. To monitor bond wire failure, we theoretically and experimentally validated the overshoot and oscillation frequency as indicators. In particular, we investigated the effects of the junction temperature and operating conditions on the overshoot and proposed their influence functions. We designed a measurement circuit to identify small changes in the overshoot. Finally, the health baselines for the overshoot under different conditions were experimentally verified. The novelty of the research lies in the accurate online monitoring for bond wire failure in IGBT modules without any external injection; the measurement circuit adopts the interrupt mode to save the controller resources. Our experimental results showed that after half the bond wire of the IGBT and the FWD failed, their voltage overshoot increased by nearly 5%.