A New Structure for the Magnetic Gear

Jing, Libing; Gong, Jinke; Huang, Zhangxian; Ben, Tong; Huang, Yuehua

doi:10.1109/access.2019.2919679

Cited by 23 publications

(14 citation statements)

References 19 publications

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“…Therefore, the 6 th relative permeance harmonic should be eliminated to reduce the cogging torque. Likewise, when (29) holds or consider other terms of ( 25), the same conclusion can be drawn. The complex relative airgap permeance is obtained by conformal mapping [32].…”

Section: A Optimization Of Cogging Torquesupporting

confidence: 54%

A Consequent-Pole Magnetic-Geared Machine With Axially Embedded Permanent Magnets for Hybrid Electric Vehicle

et al. 2021

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This paper reveals the fundamental reason for the asymmetrical issue in magnetic-geared machines (MGMs) based on flux modulation theory. The analysis indicates that the magnetic circuits of three-phase windings in MGMs are inherently asymmetrical. This asymmetrical issue is even more severe in conventional consequent-pole MGMs (CP-MGMs) because of the more distorted magnetic field. Hence, to address the asymmetrical issue, a novel structure featuring enhanced harmonic elimination capability is proposed in this paper. Consequently, torque density can also be improved. In particular, the proposed CP-MGM employs modular structure and axially embedded permanent magnets (PMs) to achieve symmetrical back electromotive force (EMF) waveforms and improved torque capability, respectively. To further improve the electromagnetic performance of the proposed CP-MGM, the PM arc ratio and flux modulator width ratio are analytically designed, which provides a general design guideline for CP-MGMs. To illustrate the merits of the proposed CP-MGM, a few other MGMs are included for a fair comparison based on finite element analysis (FEA). Results show the proposed CP-MGM can achieve more symmetrical back EMF waveforms and lower torque ripple, as well as lower PM consumption and higher torque density, as compared with its MGM counterparts.INDEX TERMS Asymmetrical magnetic circuit, cost-effective, high torque density, magnetic-geared machine.

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Section: A Optimization Of Cogging Torquesupporting

confidence: 54%

A Consequent-Pole Magnetic-Geared Machine With Axially Embedded Permanent Magnets for Hybrid Electric Vehicle

et al. 2021

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“…According to the analysis results, No. 16 with (p 1 , n 2 , p 3 ) = (3,11,8) reached the 2nd highest torque capacity with 71.5 N-m and the 6th lowest torque ripple at 0.85%, while its performance maintained a high maximum torque and torque ripple under 1%. Relatively, it's the best design of all pole-pair number designs.…”

Section: Discussionmentioning

confidence: 97%

“…Compared to conventional gear, the problem of low torque density shows up when the magnetic gear is applied for many powertrain designs; in order to overcome the torque density issue, a novel magnetic gear toward a higher torque density has been presented [4]. In general, magnetic gears have a lower torque density compared with a conventional gearbox; the torque density of magnetic gears found in the literature ranges from 70 to 162 Nm/L [5,6,7,8]. As already known, the torque density varies depending on magnetic gear design, an optimum design for SPM type magnetic gear.…”

Section: Introductionmentioning

confidence: 99%

Transmitted Torque Analysis of Coaxial Magnetic Gears with Different Pole-Pair Numbers

Tsai

2019

J. ICT des. eng. technol. sci.

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Transmitted torque is an important performance index of coaxial magnetic gears. This study focuses on the effects of pole-pair numbers on the maximum torque capacity and torque ripple of coaxial magnetic gearsOwing to the magnetic resistance between the pole piece and the medium of air; a torque ripple is generated during magnetic gear operation. In magnetic gear design, maximum torque capacity is considered the higher, the better, and the torque ripple should be the lower, the better. A commercial Finite-element analysis software AN-SYS/Maxwell 2D is applied to simulate the transmitted torque and torque ripple of coaxial magnetic gears by solving the magnetic ield, and mechanical motion coupled models. Model parameters, including size and inertia, are designed via the Autodesk/Inventor. The results of initeelement analysis have shown that there are certain relationships between pole-pair numbers and torque performance. It reveals that the sum of the pole-pair numbers is inversely proportional to the maximum torque capacity; the differences of maximum torque between different polepair number designs could be up to 82%. However, the torque ripple has not been proven for the relationship. For future research, the torque capability per cost would be necessary for magnetic gear product, especially when the price of rare earth metal is seen rising in the past years. Also, the ef iciency of magnetic gear is still important for powertrain system, but it's not easy to reach both high torque and ef iciency, owing to the lux saturation problem. The balance of torque capacity, ef iciency, and cost would be the next challenge.

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“…This structure reduces the torque ripple and peak cogging torque. Furthermore, the peak back-emf remains approximately constant [46][47][48][49].…”

Section: Bread-loaf-shaped Pm Modelmentioning

confidence: 99%

Analysis and Design of Novel Structured High Torque Density Magnetic-Geared Permanent Magnet Machine

et al. 2021

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The main limitation of magnetic gears is their relatively low torque density. Therefore, a novel structured high torque density magnetic-geared permanent magnet (MGPM) machine, which combines the advantages of a conventional MGPM machine and magnetic gear to enhance the torque considerably and achieve low-speed high-torque operation, is proposed in this study. However, there are different structures for increasing torque of a machine. Therefore, in order to demonstrate the advantages of the proposed structure, it is compared with other structures, using the finite element method. Moreover, the proposed MGPM machine can transmit an additional 42.3% of torque density when compared with the conventional MGPM machine of the same size.INDEX TERMS Bi-directional flux modulating, bread-Loaf shaped permanent magnet, dual-layer permanent magnet excitations, electrical continuously variable transmission (E-CVT), Halbach permanent magnet arrays, MGPM machine, torque density.

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A New Structure for the Magnetic Gear

Cited by 23 publications

References 19 publications

A Consequent-Pole Magnetic-Geared Machine With Axially Embedded Permanent Magnets for Hybrid Electric Vehicle

A Consequent-Pole Magnetic-Geared Machine With Axially Embedded Permanent Magnets for Hybrid Electric Vehicle

Transmitted Torque Analysis of Coaxial Magnetic Gears with Different Pole-Pair Numbers

Analysis and Design of Novel Structured High Torque Density Magnetic-Geared Permanent Magnet Machine

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