Simplified Thermal Analysis and CFD Simulation in Design Process of Power PCB Fitted with SMD

Abstract

This article discusses power losses, heating, and heat distribution on high-power PCBs fitted with high-power SMD components. The paper presents two thermal design methods for power SMD PCBs, compares them with each other, and contrasts them with reference thermal measurements on a PCB prototype. The main contribution of the paper is to evaluate simplified thermal estimation for rapid PCB prototyping and Computational Fluid Dynamics (CFD) thermal simulation for the final design and thermal optimization of the PCB in the PCB thermal design process. Therefore, the paper is divided into two parts. The first part discusses heat estimation using simplified analytical thermal calculations. The second part discusses thermal CFD modeling of PCBs and CFD thermal optimization. For verification purposes, two PCB variants are discussed—direct PCB cooling and double-sided cooling of the power SMD components. Two testing current values are used in the paper—20 A and 50 A.