A Condition Monitoring Method for Solder Layer Degradation of Liquid-Cooled Power Semiconductors

This paper presents a new method for condition monitoring of solder layer degradation of liquid-cooled power semiconductors. Solder layer degradation is detected by an increased thermal impedance, which has the effect that more heat is dissipated to the air instead to the cooling liquid. The proposed condition monitoring method is based on detecting the share of heat dissipated to the liquid and to the air. Experimental validation in a down-scaled laboratory setup is presented, with the focus on an application in an industrial converter.