Condition monitoring the thermal path degradation of IGBT module using the time constants of junction temperature cooling curves

In this paper, we propose a new method to monitor the thermal path degradation of IGBT module using the time constants of the junction temperature cooling curve. The correlation between the time constants and Cauer-type thermal parameters is investigated. Results show that the thermal path degradation of IGBT module can be monitored by detecting the variation of time constants. Simulation and experimental tests are performed to verify the effectiveness of the proposed method.