ABSTRACT Press‐pack insulated‐gate bipolar transistor (PP‐IGBT) modules are core components in high‐voltage direct‐current (HVDC) transmission power system applications. The most dominant failure mode in a PP‐IGBT module during service is fretting wear between its contact surfaces. Because the displacement amplitude of these contact surfaces is the most significant factor affecting fretting damage, a quantitative assessment of the displacement amplitude is crucial for analysing the fretting wear behaviour of a PP‐IGBT module. However, little is known about the displacement amplitude that can be induced by the relative motion of contact surfaces within a PP‐IGBT module during service. In this work, we investigate the displacement amplitude of the contact surfaces between the Si chip and the Mo emitter plate of a PP‐IGBT module during power cycling on the basis of experimental measurements, as well as the effects of loading conditions such as the load current, switching time and normal load on the displacement amplitude. The results show that the Si chip and the Mo emitter plate move reciprocally with the cyclic current fluctuation during power cycling and exhibit obvious tangential microslippage between the contact surfaces. As the load current increases, the switching time increases, the normal load decreases and the displacement amplitude of the contact surfaces increases significantly. After a certain number of cycles, slight abrasive wear occurs on the contact surfaces. This work provides an important basis for the study of fretting behaviours and the degradation mechanisms of contact surfaces of PP‐IGBT modules.
An et al. (Thu,) studied this question.