Condition Monitoring the Inhomogeneous Thermal Fatigue of Multi-chip IGBT Module Based on the Natural Frequency of Thermal Network

The inhomogeneous thermal fatigue is easily produced during the operation of multi-chip IGBT module. Condition monitoring the health status of multi-chip IGBT module can provide guidance for the regular maintenance of power converter and reduce the cost of unscheduled downtime. This paper proposed to use the natural frequency of thermal network as the characteristic quantity, and realized the condition monitoring of multi-chip IGBT module. We show that the natural frequencies increase with the degradation of multiple parallel devices. Simulations and experiments were performed to verify the proposed method. In addition, this method is able to quantify the degree of inhomogeneous thermal fatigue, which then can be used to analyze the current distribution between the parallel devices.