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Start Over Author "Zhu Z" Journal ieee transactions on magnetics
350 results on '"Zhu Z"'

1. Investigation of Ferrofluid Cooling in Modular Permanent Magnet Machines

Author

Zhang, W., Li, G. J., Zhu, Z. Q., Ren, B., Chong, Y. C., and Michon, M.

Abstract

Compared with conventional non-modular machines, the flux gaps in alternate stator teeth of the modular machines can increase the winding factor and provide flux focusing effect and hence can increase the torque/power density. In addition, the flux gaps can be used as cooling channels to improve the thermal performance. This article investigates an advanced cooling approach using ferrofluid (FF) as coolant to fill in the cavity around end windings and flux gaps. The multiphysics modeling in this article has shown that the influence of the flux gaps on machine thermal performances comes from two aspects: 1) the gravitational effect, the flux gaps allow more self-circulating coolant to transfer heat to the housing. This helps to reduce machine temperature by around 5 °C for a flux gap width of 2 mm; and 2) the magnetic body force, i.e., the thermomagnetic effect. This is very effective in non-modular machine cooling, but its efficiency slightly deteriorates in the modular machines. This is because the self-circulation of FF in the flux gaps due to the gravitational effect has been negatively affected by the thermomagnetic effect.

Published
2023
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12. Eddy current loss in the frame of a flux-switching permanent magnet machine

Author

Pang, Y., Zhu, Z. Q., Howe, D., Iwasaki, S., Deodhar, R., and Pride, A.

Subjects
Eddy currents (Electric) -- Analysis, Magnets, Permanent -- Usage, Finite element method -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

In flux-switching permanent magnet machines, a significant leakage flux exists at the outer surface of the stator core. Since the leakage flux varies as the rotor rotates, a significant eddy current loss may be induced in the nonmagnetic frame. The leakage flux and the associated eddy current loss in a representative flux-switching machine are investigated by finite element analysis, on both open-circuit and at rated load, predicted results being validated experimentally. In addition, the effectiveness of introducing slots in the frame to reduce the eddy current loss is investigated. Index Terms--Eddy current loss, flux-switching, permanent magnet machine.

Published
2006

32. Analysis of Anisotropic Bonded NdFeB Halbach Cylinders Accounting for Partial Powder Alignment

Author

Zhu, Z. Q., Xia, Z. P., Atallah, K., Jewell, G. W., and Howe, D.

Subjects
Magnetization -- Testing, Magnets, Permanent -- Usage, Injection molding -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

An analytical technique is developed for predicting the performance of a bonded Halbach oriented anisotropic magnet, with due account of partial alignment of the NdFeB powder during injection molding. The predicted performance of a 12-pole injection molded, Halbach oriented magnet is compared with measurement. Index Terms--Bonded NdFeB, electrical machine, Halbach magnetization, permanent magnet.

Published
2000

33. Influence of Design Parameters on the Starting Torque of a Single-Phase PM Brushless DC Motor

Author

Bentouati, S., Zhu, Z. Q., and Howe, D.

Subjects
Brushless electric motors -- Testing, Torque -- Testing, Business, Electronics, Electronics and electrical industries
Abstract

The starting torque of a single-phase permanent magnet brushless dc motor is investigated, for both radial and parallel magnetization. Finite element analysis is used to assess the relative merits of alternative methods of introducing the required airgap asymmetry, viz. tapered airgap, stepped airgap, asymmetric airgap, and slotted teeth. The predicted results are validated experimentally. Index Terms--Brushless dc motor, electrical machine, permanent magnet, reluctance torque.

Published
2000

34. Powder Alignment System for Anisotropic Bonded NdFeB Halbach Cylinders

Author

Zhu, Z. Q., Xia, Z. P., Atallah, K., Jewell, G. W., and Howe, D.

Subjects
Magnetization -- Models, Cylinders -- Models, Finite element method -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

A Halbach cylinder, fabricated from pre-magnetized sintered NdFeB magnet segments, is proposed for the powder aligning system during the compression or injection moulding of anisotropic bonded Halbach oriented NdFeB ring magnets. The influence of leading design parameters of the powder aligning system, viz. the number of magnet segments per pole, their axial length and radial thickness, and their clearance from the mould, is investigated by finite element analysis, and validated experimentally. Index Terms--Bonded NdFeB, Halbach magnetization, permanent magnet, powder alignment.

Published
2000

35. Eddy Current Loss in a Moving-Coil Tubular Permanent Magnet Motor

Author

Hor, P. J., Zhu, Z. Q., and Howe, D.

Subjects
Eddy currents (Electric) -- Research, Magnets, Permanent -- Research, Magnetism -- Research, Business, Electronics, Electronics and electrical industries
Abstract

The eddy current loss in the thrust rod of an iron-cored, 2-phase, tubular permanent magnet brushless motor is investigated by time-stepped transient finite element analysis. It is shown that the dominant cause of the loss is the permeance modulation which results from the teeth in the laminated thrust block, whose spacing is the same as the magnet pole-pitch. Loss predictions are validated by measurements. Index Terms--Eddy current loss, permanent magnet, linear motor.

Published
1999

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