Online Monitoring Method for IGBT Bond-Wire Lift-Off of Electric Vehicles via Phase-Current Spectral Analysis

Insulated gate bipolar transistors (IGBTs) are vulnerable components in electrified powertrain systems, considerably influencing inverter reliability and operational lifespan. Among their various failure mechanisms, bond-wire lift-off is a common package-level failure mode under real-world operating conditions, requiring accurate diagnosis and preventive management. This study focuses on bond-wire lift-off failure mode and proposes a phase-current-based diagnostic method. It is demonstrated that the amplitude of phase-current at the switching frequency increases markedly as bond-wire degradation progresses. The proposed method was validated through Simulink-based simulations and experimental tests using a three-phase inverter. The experimental results confirm that, under bond-wire lift-off fault scenarios, the amplitude at the switching frequency increases by up to six times that of the healthy state. The findings of this study indicate that the proposed method is highly effective in detecting bond-wire degradation in IGBTs and suggest the potential for integrated fault diagnosis of inverters and motors using phase-current signals alone.