Magnetic core

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

Zero-offset magnetometer having coil and core sensor controlling period of an oscillator circuit

Abstract: A magnetometer technology is provided based on a simple axial sensor which operates using the non-linear nature of saturating magnetic core material. The sensor appears electrically as an inductor with a non-linear inductance that varies both with magnetic field applied externally and the field created by the coil current. By using this sensor as the inductor of an LR relaxation oscillator, a change in applied magnetic field will cause a change in inductance, which will in turn cause a change in the oscillator period. The period of the oscillator can be converted to a digital form by using simple counting techniques. By introducing an enhancement of this scheme whereby two different periods are measured with different oscillator characteristics, the magnetometer will have no output drift when no field is applied.

Comprehensive Dynamic Loss Model of Electrical Steel Applied to FE Simulation of Electrical Machines

Abstract: This paper presents a dynamic loss model of electrical steel that can be used with the transient finite-element simulation of electrical machines. The model is used to compute the iron losses in a 37-kW induction machine fed from a sinusoidal and frequency converter voltage supply at different frequencies and loads. The computed losses are compared with results from conventional iron loss computation method based on harmonic analysis as well as with measured losses. The presented dynamic model is based on the investigation of different measurement results as well as on phenomenological backgrounds and analogies. The model is tuned to account for the rotational losses and thus can be used with arbitrary wave form or loci of the magnetic flux density vector (as is the case in the iron core of electrical machines). The parameters of the model are identified from measurements and can be stress dependent to account for the effect of mechanical stresses on the losses in magnetic materials. The presented model differs from previously presented ones in a way that the losses can be calculated at any time and not as an average over a period of the magnetic flux density.

Single magnetic push-pull forward converter featuring built-in input filter and coupled-inductor current doubler for 48 V VRM

Abstract: This paper proposes an improved push-pull forward converter with a single EI or EE core for all the magnetic components including the input inductor, the stepdown transformer and the output inductors. This topology is essentially the modified push-pull converter with the built-in input filter and the coupled-inductor current doubler rectifier. The proposed integrated magnetics features minimized leakage inductance and an air gap in only the center leg; its winding and core losses are both lower than those of conventional integrated magnetic structures.

Electromagnetic device and high-voltage generating device and method of producing electromagnetic device

Abstract: An electromagnetic device and a high-voltage generating device which are thin and have excellent performances, wherein a magnetic core (3) is formed into a columnar shape by using a large-resistivity ferrite material. Winding is formed by winding a rectangular conductor (2) edge-wise directly around the magnetic core (3) across the almost entire length thereof. Since there is no need of an insulation material such as a coil bobbin between the magnetic core (3) and the conductor (2), the outer shape of the winding can be formed small and thin to thereby make the electromagnetic device thin. The conductor (2) directly wound around the magnetic core (3) can shorten the entire length of the winding and reduce a winding resistance. The absence of a clearance between the core (3) and the winding can reduce self-inductance compared with those required by devices of, for example, the same size and the same number of turns.

Current-controlled variable inductor

Abstract: A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections. The inductance of said variable inductor is varied by varying said control magnetic flux.