Study on Condition Monitoring Method Based on Magnetic Flux Density for Multi-chips Parallel IGBT Modules

IGBT modules are widely used in various fields of power electronics, and their reliability is important for power systems. Multi-chips parallel IGBT modules face more challenges in condition monitoring and health assessment due to their complex spatial structure, uneven current distribution, and uneven temperature distribution, resulting in uneven aging. Focusing on this problem, based on the multi-physics field finite element simulation technology, the degradation law of the electrothermal and magnetic characteristic parameters during the aging failure process of the multi-chips parallel IGBT module is studied, and the magnetic flux density is used as the aging status monitoring parameter. A health status evaluation model is established for the bonding wire lift-off and solder layer aging failure modes, which is used to realize multi-chips parallel IGBT module failure type identification and quantitatively evaluate for the health status and aging chip positioning. Then, the accuracy of the health assessment model is verified by experiments, and the condition monitoring method does not require changing or touching the internal circuits of the modules. Finally, an aging failure mode based on the change of the sum of the magnetic flux density is proposed to realize the judgment of the aging failure mode and the quantitative evaluation of the health status.