Magnetic core

About: Magnetic core is a research topic. Over the lifetime, 30011 publications have been published within this topic receiving 155247 citations.

Flux Balancing of Isolation Transformers and Application of “The Magnetic Ear” for Closed-Loop Volt–Second Compensation

Abstract: Semiconductor switches possess nonideal behavior which, in case of isolated dc-dc converters, can generate dc-voltage components which are then applied to the isolation transformer. This dc-voltage component is translated into a dc flux density component in the transformer core, increasing the risk of driving the core into saturation. In this paper, a novel noninvasive flux density measurement principle, called “The Magnetic Ear,” based on sharing of magnetic path between the main and an auxiliary core is proposed. The active compensation of the transformer's dc magnetization level using this transducer is experimentally verified. Additionally, a classification of the previously reported magnetic flux measurement and balancing concepts is performed.

Experimental evaluation of the influence of DC-premagnetization on the properties of power electronic ferrites

Abstract: In many power electronic applications, ferrite cores of magnetic components are biased with a DC or low-frequency premagnetization. Usually however, the influence of the bias on the losses and permeability is not considered in the component design. This paper describes a precise measurement setup to determine the power losses and the magnetization curve of premagnetized ferrites. The measurements on typical ferrites of two major manufacturers prove that the influence of a DC-bias on the material properties cannot be neglected.

Iron loss analysis of Mn-Zn ferrite cores

Abstract: Iron loss measurements of Mn-Zn ferrite cores up to the megahertz range are reported. Taking the dc magnetic hysteresis, the eddy, and displacement currents into account, magnetic and electric field distributions in the cores are computed with the cylindrical coordinates and Bessel functions. The computed iron loss due to the magnetic and electric fields is compared with the experimental value at different exciting frequencies. It is noted that the computed iron loss becomes considerably smaller than the experimental at high frequencies. In order to explain the difference between the computed and experimental iron losses, a new magnetic field component yielding a dynamic magnetic loss is assumed and added to the magnetic field intensity of the dc magnetic hysteresis. This assumption is verified by evaluating the iron losses in different size cores composed of the same ferrite material. Displacement current distribution in a ferrite core depends on the cross-sectional area of the magnetic flux path, which brings about the dependence of the frequency characteristics of the iron loss upon core size.

Magnetic inductively-coupled connector

Abstract: An electrical connector for applications where reliability and safety are needed uses transformer couplings made in two separable sections. Upon clamping together the surrounding metal housing halves, each inductively coupled pair of transformer windings is enclosed by the associated cup-type ferrite magnetic core to minimize undesired interference and result in good magnetic coupling.