Temperature Gradient Improvement of Power Semiconductor Modules Cooled Using Forced Air Heat Sink

This paper discusses the improvement of operational reliability and lifetime of power electronic modules due to the reduction of the temperature gradient in the semiconductor structures. High temperature gradient in the power electronic modules having a large area of the semiconductor structure is a more affecting issue than the junction temperature. The improvement in the temperature gradient is achieved by varying/degrading the thermal resistance along the heat sink length. A conventional cooling system for three semiconductor modules based on a forced air heat sink was modelled and analysed to derive a reduction rate of the appropriate thermal resistances. Implementation of the forced air heat sink having non-uniformed thermal resistances along the heat sink length ensures the uniform temperature distribution across the power semiconductors and, therefore, the improved thermal gradient.