A Novel Bond Wire Fault Detection Method for IGBT Modules Based on Turn-on Gate Voltage Overshoot

Bond wire degradation is one of the most common failure modes for wire-welded packaging insulated-gate bipolar transistor (IGBT) modules. This article proposes a novel bond wire detection method based on IGBT turn- on gate voltage overshoot. The degree of bond wires lift-off will change the stray inductance of the gate charge loop circuit, and therefore has a strong influence on turn- on gate voltage overshoot before miller platform, which can be used as an effective bond wire fault indicator. A double pulse test platform is built to verify the resolution and sensitivity of the proposed precursor for bond wire degradation. The dependences on bus voltages, load currents, junction temperatures are discussed and tested. The experimental results show that the gate turn- on voltage overshoot of IGBT increases with the increasing severity of bond wire faults, which agrees with the theoretical analysis. The proposed turn- on gate voltage overshoot-based method has a high sensitivity for identifying bond wire fault at the incipient stage. It offers an effective technique for detecting bond wire degradation for practical applications.