Magnetic core

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

High-Frequency Behavioral Ring Core Inductor Model

Abstract: The switching of the power semiconductors in static converters is the main source of electromagnetic interferences (EMI). To meet with electromagnetic compatibility standards, it is necessary to reduce the level of the conducted emissions. This reduction can be achieved by different techniques including the EMI filters whose design is mainly based on the use of ring core inductors. This element is a key point for designing efficient EMI filters, requiring then accurate inductor high-frequency (HF) models. Therefore, this paper deals with the development of an HF behavioral model of inductors, based on electrical equivalent circuit, for an implementation in circuit simulation software. The aim is to provide a robust and adjustable model under small-signal operating conditions for frequencies up to 100 MHz. The proposed model considers the frequency-dependent properties of the magnetic core material and also includes the parameterization of the electrical equivalent circuit elements with the number of winding turns and dimension of the magnetic core. Simulations results using the obtained inductor model are validated by impedance measurements with two types of magnetic materials: ferrite and nanocrystalline.

Ground fault sensing circuit

Abstract: There is disclosed a ground fault sensing circuit usable with either AC or DC circuits. It includes a closed loop magnetic core having a gap. Two windings are disposed on the core in series, respectively, with the different conductors supplying the load. The windings are arranged in such a manner that, when the currents in the conductors are equal, there is no magnetic flux produced in the core and gap. Positioned in the gap is a solid state magnetic field sensitive element such as a Hall effect device or magnetic transistor. Underground fault conditions, a magnetic field appears across the gap and an output signal is generated by the solid state device. This signal is amplified and trips a circuit breaker in series with the load.

Multi-armature motors

Abstract: A direct current motor having at least two armatures arranged in parallel between parallel magnetic circuits established through the armatures independently exciting the armatures. In one embodiment a pair of iron core coils, positioned on respective opposing sides of a pair of armatures, provides the magnetic circuit. In another embodiment an iron core coil, interposed between two or more parallel armatures, forms the magnetic circuit. This common source of magnetic excitation forms parallel magnetic circuits wherein the motor has a dual operating characteristic in that the speed of one armature varies inversely with the speed of the other armature and vice versa until the higher speed armature reaches its critical rpm permitting the load to be increased without further change in the speed of either armature.

High inductance planar transformers

Abstract: We have developed a new printed circuit board PCB technology adapted for the fabrication of ultra-flat microtransformers. The two outer layers of the PCB stack comprise the electrical windings of the inductive devices, while the inner layer is made of a micro-patterned . amorphous magnetic ribbon with extremely high relative magnetic permeability m f 100,000 . The electrical properties of the toroidal r microtransformers have been studied as a function of frequency. Inductances were found to be as much as 30 mH at 1 kHz, a relatively high value compared to microtransformers of similar size. Despite a relatively high leakage flux, the voltage transformation efficiency is measured at 89%. The high performance of these devices is primarily due to the use of the high permeability magnetic core. q 2000 Elsevier Science S.A. All rights reserved.

Method of making electronic transformer/inductor devices

Abstract: Methods of construction for inductive components such as inductors, chokes, and transformers enable these components to be fabricated using mass production techniques, thereby avoiding the need to handle discrete devices during the manufacturing process. In one preferred embodiment, holes are formed through a ferromagnetic substrate and plated with conductive material. The arrangement of these holes, and the subsequent design that ensues, will form the inductive components within the plane of the media in which the device is formed; using the substrate for a magnetic core. By using this approach, the inductive components can be miniaturized to physical sizes compatible with the requirements of modern surface mount technology (SMT) for integrated circuitry (IC). In another preferred embodiment, a series of thin, concentric high permeability rings are etched on a substrate to provide high permeability transformers and inductors having minimal eddy current effects.