Non-Intrusive Case Temperature Measurement Method of Direct-Water-Cooled Power Module

In this paper, we present a non-intrusive case temperature measurement method of the direct-water-cooled power module. It uses the structure function, which in this case comprises the cumulative thermal capacitance and the cumulative thermal resistance. Since the effective heat transfer rate of the pinfin heatsink varies with the water flow rate, in this study we assumed the inflection point of the structure function corresponding to the change in the flow rate was junction-case thermal resistance. We compared numerical simulation results with experimental results and present our findings. Finally, we show that the design area in which the heat spreading angle of 45 degrees, the well-known rule of thumb, is suitable.Copyright © 2015 by ASME