Design of a flyback transformer using a stress-annealed iron-based nanocrystalline alloy

¹ Power Electronic research team, LESIR/SATIE, ESA 8029, ENS de Cachan, 61 avenue du Président Wilson, 94230 Cachan, France
² Magnetic Materials research team, LESIR/SATIE, ESA 8029, ENS de Cachan, 61 avenue du Président Wilson, 94230 Cachan, France

Corresponding author: alves@lesir.ens-cachan.fr

Received: 21 January 2002
Revised: 5 March 2002
Accepted: 26 March 2002
Published online: 6 June 2002

Abstract

This paper presents some results from experiments carried out on a flyback converter whose transformer has been built with a new stress-annealed nanocrystalline (iron-based) material developed by our laboratory team. This original process has provided a low value of relative permeability (around 200) at a high induction level, thereby making it possible to store large amounts of energy. A flyback transformer without air-gap was thus tested in order to evaluate the performance of this material, with highly satisfactory results being obtained. Because of the material's low magnetic losses at a high induction level and high-frequency switching (up to 25 kHz), low transformer losses along with a low temperature rise were observed. A figure of merit is proposed in order to situate our material performances among others.