Air-Water Cooling System for Switch-Mode Power Supplies

G Casano,S Piva

doi:10.4236/jectc.2015.53005

Abstract

The results are presented of an experimental investigation of heat transfer in an air-liquid cooling system for a Switch-Mode Power Supply (SMPS) for TV digital power amplifiers. Since these SMPSs are characterized by high power and high compactness, thereby making the standard cooling techniques difficult to be used, a new cooling system is developed, using water and air as the cooling media. The active components (MOSFETs) are cooled with a liquid cold-plate, the passive ones (condensers, transformers, coils) with an air flow, in turn cooled by the cold-plate. By inserting the cooling system in an experimental tool where it is possible to control the cooling water, measurements are made of temperature in the significant points of the SMPS. The electric efficiency is also measured. The evaluation of the thermal performance of this cooling system is useful in order to limit its maximum operational temperature. The efficacy of the cooling system is demonstrated; the trends of efficiency and power dissipation are evidenced.

Highlights

In recent times, switching regulators are used as replacements for traditional regulators when high efficiency, small size and low weight are required [1]
It is difficult with a cold plate to maintain the printed circuit board (PCB) and these passive components at the design temperature, because they are originally developed for air cooling
Due to the presence of the air-cooling system, it was impossible for us an analysis of the temperature distribution on the PCB with infrared thermography, as suggested in [6]

Summary

Introduction

In recent times, switching regulators are used as replacements for traditional (linear) regulators when high efficiency, small size and low weight are required [1]. While it is easy to collocate the active components on a cold plate, the large number of passive components of a SMPS, like condensers, transformers and coils, needs to be placed on a printed circuit board (PCB). It is difficult with a cold plate to maintain the PCB and these passive components at the design temperature, because they are originally developed for air cooling.

Experiment

Test Section

Hydraulic Loop

Data Reduction and Measuring Uncertainties

Results and Discussion

Concluding Remarks