scispace - formally typeset
Search or ask a question
Topic

Magnetic core

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


Papers
More filters
Proceedings ArticleDOI
02 Oct 1994
TL;DR: In this article, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots.
Abstract: Super high-speed and high-power electric machines are required for turbomolecular pumps and spindle drives. High rotational speed and high power drives can be achieved with bearingless motors. In this paper, a bearingless motor with the principles of permanent magnet type synchronous motors is proposed. High power factor and high efficiency can be expected in permanent magnet type bearingless motors. The proposed bearingless motor is a 4 pole permanent magnet synchronous motor, in which additional 2-pole windings are wound together with 4-pole motor windings in stator slots. With currents of 2-pole windings, radial magnetic forces are produced to support a rotor shaft. Principles of radial force production of surface-mounted permanent magnet bearingless motors are analyzed mathematically. It was found that radial forces are efficiently produced by employing thin permanent magnets on the surface of rotor iron core. A test machine was built in order to measure inductance functions as well as relationships between voltages and currents.

97 citations

Journal ArticleDOI
TL;DR: This work designs novel and facile CoxFey@C composites by reducing CoxFe3−xO4@phenolic resin and shows excellent electromagnetic absorption properties, and the mechanisms of the improved microwave absorption properties are discussed.
Abstract: The shell on the nano-magnetic absorber can prevent oxidation, which is very important for its practical utilization. Generally, the nonmagnetic shell will decrease the integral magnetic loss and thus weaken the electromagnetic absorption. However, maintaining the original absorption properties of the magnetic core is a major challenge. Here, we designed novel and facile CoxFey@C composites by reducing CoxFe3−xO4@phenolic resin (x = 1, 0.5 and 0.25). High saturation magnetization value (Ms) of CoxFey particle, as a core, shows the interesting magnetic loss ability. Meanwhile, the carbon shell may increase the integral dielectric loss. The resulting composite shows excellent electromagnetic absorption properties. For example, at a coating thickness of 2 mm, the RLmin value can reach to −23 dB with an effective frequency range of 7 GHz (11–18 GHz). The mechanisms of the improved microwave absorption properties are discussed.

97 citations

Journal ArticleDOI
TL;DR: In this article, a coreless printed circuit board (PCB) transformer for isolated gate drive circuits over a wide-frequency range has been proposed, based on a resonance concept, the optimal operating condition that minimizes the power consumption of the gate drive circuit is developed and verified with experiments.
Abstract: Gate drive circuits for power MOSFETs and insulated gate bipolar transistors (IGBTs) often require electrical isolation. Coreless printed circuit board (PCB) transformers have been shown to have desirable characteristics from a few hundreds of hertz to a few megahertz and can be used for both power and signal transfer at low-power level. At low operating frequency, the magnetizing inductance has such low impedance that the driving power requirement could become excessive. This paper describes the use of a coreless PCB transformer for isolated gate drive circuits over a wide-frequency range. Based on a resonance concept, the optimal operating condition that minimizes the power consumption of the gate drive circuits is developed and verified with experiments. The coreless PCB transformer demonstrated here confirms a fundamental concept that the size and volume of a magnetic core could approach zero and become zero if the operating frequency is sufficiently high. Coreless PCB transformers do not require the manual winding procedure and thus simplify the manufacturing process of transformer-isolated gate drive circuits and low-power converters. Their sizes can be much smaller than those of typical core-based pulse transformers. The electrical isolation of a PCB is much higher than that of an optocoupler.

97 citations

Journal ArticleDOI
TL;DR: In this article, the authors analyze various aspects of designing planar inductive circuits based on magnetic films as well as demonstrate substantially enhanced inductance characteristics for some prototype structures for planar IR structures.
Abstract: Responding to the increasing demand for miniaturization and circuit integration of rf inductors we analyze various aspects of designing planar inductive circuits based on magnetic films as well as demonstrate substantially enhanced inductance characteristics for some prototype structures.

96 citations

Patent
Dirk J. Boomgaard1
16 Feb 1989
TL;DR: In this article, the authors proposed a directional common mode trap located between the point where the communication signals are applied to the power line and the source of the electrical noise, which requires only a capacitor for each electrical phase and a 1:1 transformer having a magnetic core and single turn straight through windings.
Abstract: A power line communication system which includes an electrical power line having one or more loads which feed objectionable electrical noise back into the power line. The electrical noise is attenuated across a broad frequency range to enable effective communication over the power line by a directional common mode trap located between the point where the communication signals are applied to the power line and the source of the electrical noise. The trap requires only a capacitor for each electrical phase and a 1:1 transformer having a magnetic core and single turn, straight through windings. The trap is connected to provide a low impedance path to ground for the electrical noise, while providing a high impedance to ground for the communication signals.

96 citations


Network Information
Related Topics (5)
Electromagnetic coil
187.8K papers, 1.1M citations
88% related
Voltage
296.3K papers, 1.7M citations
86% related
Capacitor
166.6K papers, 1.4M citations
84% related
Rotor (electric)
179.9K papers, 1.2M citations
84% related
Electric power system
133K papers, 1.7M citations
80% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202365
2022163
2021309
2020900
20191,254
20181,426