In Situ Diagnosis of Multi-site Wire Bonding Failures for Multichip IGBT Power Modules Based on Crosstalk Voltage

The online detection of aging bond wires is key to the health status awareness of smart power converters. In this paper, a new health precursor of the gate voltage undershoot V_GE(pk) of the complementary switch in the half-bridge structure is proposed. It can be used to identify and distinguish multi-site bonding wire failures for both insulated gate bipolar transistors (IGBTs) and freewheeling diodes (FWDs) in multichip IGBT modules. A theoretical analysis is conducted to derive this novel precursor, which is then verified by experimental results. Then, a dedicated read-out circuit is designed for the data acquisition front end that can be integrated into gate drivers for in-situ monitoring. Finally, the effectiveness of this method is evaluated under changing operating conditions including the DC-bus voltage, the load current, and the junction temperature. The effects of their fluctuations are studied and quantified, with corresponding calibration relationships provided to improve precursor accuracy.