Thermal Modeling of Fan-Cooled Plate–Fin Heatsink Considering Air Temperature Rise for Virtual Prototyping of Power Electronics

Abstract

To develop a thermal model for air-cooled plate–fin heatsink and evaluate its thermal performance, empirical equations are available to rapidly calculate the pressure drop and heat transfer coefficients for the fins. Besides the heat transfer coefficients, the local air temperature also affects the heat transfer of the fins, which rises along the channel by absorbing the released heat from the fins. In this article, a heatsink model to account for the air temperature rise is proposed, and a thermal circuit model is used to correlate the increased air temperature and the absorbed heat at the fin boundary. With this convective boundary, the temperature distribution for the base plate of the heatsink is calculated by adopting finite-difference method (FDM), which analyzes the conductive heat transfer for the base plate. Both of them have been programed in MATLAB software, and the calculated temperature by the proposed models is compared with the computational fluid dynamics (CFD) simulation. A fan-cooled plate–fin heatsink for a half-bridge power electronics inverter is tested in the laboratory as an example, and the thermal results obtained from the proposed models are within 10% of error with respect to the CFD simulation results and experimental results. The proposed method is also faster than the CFD simulation. The proposed accurate and rapid thermal modeling method will be essential for virtual prototyping and layout/geometry optimization of power electronics systems.