Magnetic core

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

Mixed fault diagnosis in three-phase squirrel-cage induction motor using analysis of air-gap magnetic field

Abstract: In this paper fault diagnosis of induction motor under mixed fault is carried out using precise analysis of the air-gap magnetic field based on time stepping finite element method. By feeding voltage instead of current density to the finite element computation part, the drawbacks of the application of finite element method in fault diagnosis of induction motor are overcome. Normally static eccentricity and broken rotor bars faults have been individually diagnosed in the published papers. Here diagnosis of the mixed fault,including static eccentricity and broken rotor bars,is introduced which is considered as a novel part of the present work. Precise analysis of magnetic field in the air-gap of a faulty induction motor is carried and performance of the motor is predicted. Taking into account the magnetic core saturation is another advantage of the present work. This is required in the transient analysis of a faulty motor.

Microconverter and laminated magnetic-core inductor

Abstract: A surface-mount microconverter is formed by mounting a microinductor chip and a semiconductor integrated circuit chip on a circuit board. Stud terminals are arranged on the circuit board and the microinductor chip is supported on the stud terminals, and the microinductor chip and the semiconductor integrated circuit chip are superposed on the circuit board. The microconverter has an improved ability and is small and thin. The microconverter includes an effective laminated magnetic-core inductor. The inductor comprises a helical coil formed by uniting alternately superposed insulating magnetic layers and conductive pattern layers, and an annular closed magnetic path formed by the insulating magnetic layers and defining a magnetic field created by the coil. The inductor can be miniaturized in a thin chip, and a wide range in which magnetic flux density varies linearly can be secured by balancing a closed magnetic path for a magnetic field created by the coil.

Equivalent circuit of mush wound AC windings for high frequency analysis

Abstract: The paper describes a lumped parameter equivalent circuit for the HF analysis of mush wound coils of AC windings. The equivalent circuit takes account of turn-to-turn and turn-to-iron stray capacitances. Dissipative phenomena due to eddy currents in the coil wires and the laminated iron core are also considered. The parameter identification is based on sinusoidal impedance measurements on a test coil. The model of a multi-coil AC stator winding can be easily derived from the proposed equivalent circuit. This model allows one to predict both common- and differential-mode conducted EMI in switching converters supplying AC motors. The simulation results obtained by PSpice are in good agreement with the experimental data.

Experimental Determination of Equivalent-Circuit Parameters of a Tubular Switched Reluctance Machine With Solid-Steel Magnetic Core

Abstract: The model-based analysis of a switched reluctance machine, which has significant losses in the iron core, requires the machine to be represented by parameters that account for nonlinearities caused by both the magnetic saturation and the iron losses. This paper describes the methodology for determining the parameters of the equivalent electric circuit that includes the representation of iron losses. The parameters are derived from measurements performed under static conditions. The methodology is verified by comparing the dynamically measured results for the pull-out force against the results predicted by the model that is based on the equivalent circuit.

High- Q Three-Dimensional Microfabricated Magnetic-Core Toroidal Inductors for Power Supplies in Package

Abstract: The integration of power inductors is a roadblock in realizing highly miniaturized power supply in package (PSiP) and power supply on chip. Inductors in such power systems are used for energy storage and filtering, but they dominate in size and loss. This paper presents a novel three-dimensional in-silicon through-silicon via (TSV) magnetic-core toroidal inductor for PSiP. The magnetic powder based core is embedded into a TSV air-core inductor using a casting method. The unique air-core inductor design with a hollow core and suspended windings enables a complete core filling with microscale magnetic powders. The proposed casting method is simple, scalable, and generic for a wide range of magnetic powders. TSV magnetic-core inductors are fabricated in a compact size of 2.4 mm × 2.4 mm × 0.28 mm with the core content varying from 63 to 88 wt% of soft ferrite NiZn powders. The TSV magnetic-core toroidal inductors are fabricated and electrically characterized. Small-signal measurements show a threefold higher inductance of 112 nH and a 30% higher quality factor of 14.3 at 12.5 MHz for magnetic-core inductors compared with similar TSV air-core inductors. The small-signal measurement results are verified by the modeled results. The total core loss is characterized by large-signal measurements. A suitable inductor is implemented in a 12-MHz buck converter that operates in a zero-voltage-switching mode. The converter achieves a peak efficiency of 71.6% and an output power of 2.4 W while converting 12 to 5 Vdc.