Development of a Computational Fluid Dynamics Model to Evaluate the Thermal Resistance of a SiC Power Module under Several Operating Condition

This study developed a 3D Computational Fluid Dynamics (CFD) model to compute the thermal resistance of the SiC-based direct cooled ACEPACK™ DRIVE power module, by STMicroelectronics. The model was validated with respect to experimental data. The model investigate regarding the temperature dependency of materials thermal conductivity. In more detail, two different thermal conductivity values for solder layer were considered, showing their significant impact on thermal resistance. After adjusting for this parameter and taking into account the effects of temperature-dependent thermal conductivity of the active metal brazing (AMB) substrate, the model showed good accuracy with an error ranging from 0.5% to 1.6%. Furthermore, the CFD model was used to investigate the influence of the non-linear thermal conductivity of the AMB on thermal resistance, finding that it varies as a polynomial function of flow rates and increases linearly with dissipated power.