Ferrites and Nanocrystalline Alloys Applied to DC–DC Converters for Renewable Energies

Dante Ruiz,Claudio Fuerte,Héctor Vergara,Edgar Moreno,Alejandro Vargas,Jorge Ortíz,Vicente Venegas

doi:10.3390/app12020709

Abstract

The medium frequency transformer (MFT) with nanocrystalline alloys is quintessential in new DC–DC converters involved in various front-end applications. The center piece to achieve high-performance, efficient MFTs is the core. There are various options of core materials; however, no deep information is available about which material characteristics and design procedure combo are best to get high performance MFTs while operating at maximal power density. To provide new insights about interrelation between the selection of the core material with the compliance technical specifications, differently to other proposals, this research work aims to design and build, with the same methodology, two MFT prototypes at 20 kHz, with nanocrystalline and ferrite cores, to highlight power density, and overall performance and cost, as matching design criteria. As the experimental results show, a nanocrystalline core has the highest power density (36.91 kW/L), designed at 0.8 T to obtain low losses at 20 kHz, achieving an efficiency of 99.7%. The power density in the ferrite MFT is 56.4% lower than in the nanocrystalline MFT. However, regarding construction cost, the ferrite MFT is 46% lower, providing this a trend towards low-cost DC–DC converters. Finally, high power density in MFTs increases the power density of power DC–DC converters, which have relevant applications in fuel cell-supplied systems, renewable energies, electric vehicles, and solid-state transformers.

Highlights

Introductionmedium frequency transformer (MFT), are fundamental to the development of newly advanced DC–DC converters [1,2,3,4]
An important point is the selection of the core material in the pursuit of achieving high power density and excellent efficiency of the medium frequency transformer (MFT) [11,12,13,14,15]
The analysis and results presented in this paper highlight the better performance, 56.4% higher in terms of the power density, for instance, of the nanocrystalline MFT compared to the ferrite MFT

Summary

Introduction

MFTs, are fundamental to the development of newly advanced DC–DC converters [1,2,3,4]. Different from the previous materials, nanocrystalline alloys are a high-cost material (considering per unit of volume) compared to ferrites and silicon steel. It has higher permeability, lower core losses, and a higher design flux density in the 1 to 5 kHz range [16,17,19]

Objectives

Findings

Discussion

Conclusion