A report of the heat dissipation FEM simulation of the low height power supply unit for IP communications systems

This paper describes a heat dissipation design of a low height and high density power supply unit utilizing a finite element method (FEM) simulation. This power supply unit has a size that can be installed in a 1 U (44.45 mm) of a 19-inch rack (EIA standard). An output power is designed at 1,365 W and a loss is about 156 W. A heat density is 59.2 (W/l). In this process, we performed four steps of heat dissipation FEM simulations in order to effectively layout the main components. Based on the result of the simulation, we fabricate a prototype unit. A comparison between the simulation model and the actual experimental data shows that the simulation result is very reliable. However, an error on a transformer temperature is found to be large. After some study, it is determined that detailed modeling of a winding of the transformer is important to obtain the overall accuracy from the FEM simulation. In conclusion, it is proved that the heat dissipation FEM simulation is one of the most effective methods in development the low height and high-density power supply units for the IP communications systems.