Novel Flexible Nanocrystalline Flake Ribbons for High-Frequency Transformer Design

Abstract

The eddy current loss for nanocrystalline alloys is detrimental at high frequencies due to the low material resistivity. Novel flexible nanocrystalline flake ribbons fabricated from Fe-based nanocrystalline alloys are introduced to solve the problem. In this paper, the manufacturing process of a novel material and the mechanism of reducing eddy current loss are described. The material characterisation and magnetic measurement of nanocrystalline flake ribbons are given. The core losses of nanocrystalline flake ribbons and conventional nanocrystalline ribbons are compared. The experimental results show that the core losses of nanocrystalline flake ribbons decrease by 30% compared to the corresponding nanocrystalline ribbons. Following an optimal design procedure, high frequency (HF) transformers built by the flake ribbons and ferrites are tested in a 1.2 kW DAB converter, and the core losses are reduced by over 50% compared with ferrite transformers.