Condition Monitoring of IGBT Module and Forced Air Cooling System Using Time Constants of Heat Sink Temperature Cooling Curve

This paper proposes a new method that uses the time constant of heat sink temperature cooling curve as an indicator to monitor the solder fatigue of insulated gate bipolar transistor (IGBT) module as well as the deterioration of the cooling system. This approach is based on the direct correspondence between a certain time constant of the heat sink temperature cooling curve and the thermal parameters of a given part of the cascaded thermal system. The aging of IGBT module and the cooling system can be monitored by detecting the variations of corresponding time constants. Experimental tests were conducted to demonstrate the effectiveness and accuracy of this technique.