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 (V-CZ,V-ON) is a frequently employed failure precursor to identify the bond wire aging. In this paper, a method of separating V-CZ,V-ON is proposed to monitor the bond wire lift-off of IGBT module. Firstly, based on the circuit structure of IGBT module, the VczoN is divided into voltage drop across IGBT chip (V-CZ,V-ON) and voltage drop across bond wire (V-RW). Secondly, the working principle of IGBT chip is investigated, and the calculation method of voltage drop across P-i-N diode (V-PIN) is proposed. Finally, the V-Chy, is analyzed, and information provided by collector current (I-C) at the IC-VCHtp, curve intersection point that is not affected by solder layer fatigue is adoptedto monitor the lift-off degree of bond wire. The feasibility of the above methods is verified by theory and experiment