Retrieving heat transfer coefficient temperature dependence from measurement data

This paper discusses on the practical example of a power diode the problem of the heat transfer coefficient dependence on temperature and its impact on device junction temperature when the thermal resistance is dominated by the heat exchange with ambient, e.g. for the free convection cooling. The proper determination of this dependence is crucial for the accurate computation of the device operating point. Here, the problem illustrated based on the analysis of a series of temperature measurements taken for different amount of power dissipated in the device attached to a heat sink. For each measurement, a compact dynamic thermal model is generated employing the Network Identification by Deconvolution method. Then, the influence of temperature on different model element values is investigated and the variation of the heat transfer coefficient with temperature is estimated.