Experimental investigation of high-flux density magnetic materials for high-current inductors in hybrid-electric vehicle DC-DC converters

High-flux-density materials, such as iron-based amorphous metal and 6.5% silicon steel for gapped inductors, and powdered alloys for gapless inductors, are very competitive for high-power-density inductors. The high-flux-density materials lead to low weight/volume solutions for high-power dc-dc converters used in hybrid-electric and electric vehicles. In this paper, the practical effects of frequency, dc bias, flux-density de-rating, the duty cycle, air-gap fringing on the core and winding, and thermal configuration based on lamination direction are investigated for iron-based amorphous metal, 6.5% silicon steel and iron-based powdered alloy material. A 2.5 kW converter is built to verify the optimum material selection and thermal configuration. Analytical, simulation, and experimental results are presented.