Characteristics of Electric and Magnetic Circuit Parameters in Thread-Type Magnetic Core System

This paper presents the characteristics of a thread-type magnetic core system in terms of the electric and magnetic circuit parameters. The thread-type core, a magnetic core with a new structure, is composed of iron threads surrounded by an insulator. In the previous study, it was shown that the thread-type core can reduce an amount of iron loss [1]. In this study, the characteristics of the thread-type core are quantified in terms of the electric and magnetic circuit parameters such as iron loss resistance, magnetizing inductance, and reluctance. These parameters are compared with those of bulk- and lamination-type core systems. The circuit parameters are calculated using a numerical analysis of the finite-element method, and the calculated parameters are also compared with experimental data. The comparison shows that the thread-type core exhibits improved system parameters for magnetic systems, particularly in the high-frequency range. This means that the thread-type core has advantages in efficiency, core size, and power capacity. An additional numerical analysis shows that the more segmented thread-type core results in further improved performance.

I. Introduction

Eddy currents have adverse effects on electric machines and are one of the factors that engineers should consider when designing magnetic core systems. To reduce the eddy current, a ferromagnetic material is mixed with impurities and laminated in electrical steel sheets. Furthermore, new magnetic materials with higher efficiency and better performance, such as Permalloy and nano-crystalline alloy powders, are still under development [2]–[4]. However, the manufacture of these materials requires some complicated and expensive processes. Moreover, in developing a new material with a specific property, it is difficult to characterize in advance a material that is composed of more than two compounds [5], [6].