Bond wire lift-off monitoring based on intersection point movement characteristic in IGBT module

Condition monitoring (CM) the insulated-gate bipolar transistor (IGBT) module is of vital significance to improve the reliability of power electronics system. Collector–emitter on-state voltage VCE,ON is a frequently employed failure precursor to identify the bond wire aging. In this paper, a method of separating VCE,ON is proposed to monitor the bond wire lift-off of IGBT module. Firstly, based on the circuit structure of IGBT module, the VCE,ON is divided into voltage drop across IGBT chip VChip and voltage drop across bond wire VBW. Secondly, the working principle of IGBT chip is investigated, and the calculation method of voltage drop across P-i-N diode VPiN is proposed. Finally, the VChip is analyzed, and information provided by collector current IC at the IC–VChip curve intersection point that is not affected by solder layer fatigue is adopted to monitor the lift-off degree of bond wire. The feasibility of the above methods is verified by theory and experiment.