The Development of New Amorphous Cores forHigh Frequency Power Applications


The Development of New Amorphous Cores forHigh Frequency Power Applications

Increased electrification is driving the development of more efficient energy solutions for all market segments. Designers of semiconductor technology have developed new methods for switching such as soft switching or zero current switching, which have contributed to increased bandwidth and the introduction of devices using GaN and SiC materials. Increased bandwidth helps to reduce the size of magnetic components as the magnetizing inductance increases, yet core materials can struggle to dissipate less power as the frequency increases. Typically, materials with high flux density and low coercivity exhibit excess core losses as the frequency approaches 1 MHz.This paper introduces new core material research published at APEC 2019 and PCIM 2019 by Bourns in collaboration with Tyndall Research Institute. The purpose of developing new magnetic materials is to achieve minimal core losses at high switching frequencies. Get more news about Amorphous core,you can vist our website!
Magnetic materials differ from non-magnetic materials by the way they react when a magnetic field is applied. If a magnetic field is generated, the atoms in magnetic materials will experience a torque proportional to the flux density in the field by a vector quantity called the magnetic moment. A strip of magnetic material can be described furthermore by groups of magnetic moments, known as domains, where every domain has a different direction. Once a field is applied,the domains will align along the direction where the least amount of energy is lost (called the easy axis as shown in Figure 1). All magnetic materials have these qualities although some have higher anisotropic energies, which is the energy required to rotate the magnetic domains to a saturated state where the applied field has no effect, than others and a few materials enable better performance at different switching frequencies compared to others.
The chart in Figure 2 shows that amorphous materials have a good mixture of coercivity and saturation flux density. The composition of amorphous materials consists of trace elements such as Cobalt and Iron together with mixtures of Silicon and other elements such as Niobium. One of the objectives of this research was to prepare and test amorphous material which did not depend on traditional elements and resulted in reducing the material cost by 30 %. The experimental material used in this research was based on Cobalt and Iron and other elements. In order to prepare the material, the elements were carefully weighed and arc-melted at
temperatures of 4000 °C in an arc furnace producing 1 g ingots. The ingots were subsequently put into an induction heater and the molten liquid ejected onto a spinning disk and cooled at a very severe rate (1 million degrees per second) producing 20 µm thick, 1 mm wide ribbons into a quartz vial. Figure 3 illustrates the steps taken in the first stage of making the material.

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