Magnetic Couplings With Cylindrical and Plane Air Gaps: Influence of the Magnet Polarization Direction.

Ravaud, Romain; Lemarquand, Guy

doi:10.2528/pierb09051903

Cited by 19 publications

(7 citation statements)

References 37 publications

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“…Torques transmitted in permanent magnetic couplings are subject of recent research [37][38][39][40][41][42]. The force density of a magnetic field onto some magnetization pointing in z-direction is f = M ∇B z .…”

Section: Torques Between Multi-polar Discsmentioning

confidence: 99%

Closed Analytical Formulae for Multi-Pole Magnetic Rings

Ausserlechner¹

2012

PIER B

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Abstract-Multi-pole permanent magnetic encoders are used for wheel speed sensing in automotive systems. This paper discusses rings and discs magnetized along axial direction. The vector field is calculated analytically in 3D as sums over all poles. For the case of discs with vanishing inner and infinite outer diameter the summation is done in closed form with a new summation formula. The results are discussed and several plots of field patterns are given in normalized form: At very small air-gap the field shows an overshoot. At moderate and large air-gaps it is a sine-function with exponentially decaying amplitude. The amplitude versus air gap, reading radius, thickness of the magnetic layer, and number of poles is studied and excellent agreement with measurements is found. The effect of a steel-back on the field is explained. It is also shown how to maximize the torque transmitted in axially magnetized couplings.

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Section: Torques Between Multi-polar Discsmentioning

confidence: 99%

Closed Analytical Formulae for Multi-Pole Magnetic Rings

Ausserlechner¹

2012

PIER B

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“…In order to compute the PMCs torque the field from each individual magnet is typically first determined and then the magnet's fields are summed up and used to compute the torque. Examples of authors using this approach are given in [2][3][4][5]. Frédéric [5] for instance, then used such a technique to study the performance of different magnetic couplings that utilize rectangular magnets.…”

Section: Introductionmentioning

confidence: 99%

Ideal Radial Permanent Magnet Coupling Torque Density Analysis

Bird

Acharya

2017

IEEE Trans. Magn.

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“…An exact calculation of them is vitally important for their design and optimization [4][5][6][7]. The common method for magnetic field calculation is either analytical method or numerical method (especially the finite element method, FEM) [6][7][8][9][10]. The CMGs have two air-gaps between the inner and the outer rotor which are isolated by ferromagnetic polepieces.…”

Section: Introductionmentioning

confidence: 99%

A Three Dimensional Analytical Calculation of the Air-Gap Magnetic Field and Torque of Coaxial Magnetic Gears

Ge¹,

Nie²,

Xin³

2012

PIER

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Abstract-In order to solve the defects that the end-effect of magnetic field is ignored in two dimension (2-D) analytical method or 2-D finite element method (FEM); meanwhile, mass computer resource and time for parametric design or optimization are wasted in three dimension (3-D) FEM, a concise and efficient 3-D analytical approach is put forward for the calculation of the air-gap magnetic field and torque of coaxial magnetic gears. Based on the cylindrical coordinates where a coaxial magnetic gear is in, the equivalent current model and vector magnetic potential equation of permanent magnets in high speed permanent magnetic ring are constituted. By superposed magnetic flux density of every tile permanent magnets on high speed permanent magnetic ring in cylindrical coordinates, a air-gap magnetic field 3-D analytical formula is set up without ferromagnetic pole-pieces; in the interest of modulated air-gap magnetic field 3-D analytical formula with ferromagnetic pole-pieces, three types boundary conditions using state equations of contact surfaces between ferromagnetic pole-pieces and air-gap are established by a thorough analysis of the modulate mechanism of ferromagnetic pole-pieces. Finally, magnets of the low speed permanent magnetic ring are reduced to a distribution of equivalent current, which experience the Lorentz force in modulated magnetic field of high speed permanent magnetic ring for torque calculation. The integrals in all aforementioned calculation are axial, so the end-effect is embodied in above analytical model and more precise than 2-D analytical method or 2-D FEM. As the calculation results, the formula is accurate but faster than the 3-D FEM. The analytical model is suited for programmable calculation and that will make the structural and parametric design or optimization of coaxial magnetic gears simple and timesaving.

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Magnetic Couplings With Cylindrical and Plane Air Gaps: Influence of the Magnet Polarization Direction.

Cited by 19 publications

References 37 publications

Closed Analytical Formulae for Multi-Pole Magnetic Rings

Closed Analytical Formulae for Multi-Pole Magnetic Rings

Ideal Radial Permanent Magnet Coupling Torque Density Analysis

A Three Dimensional Analytical Calculation of the Air-Gap Magnetic Field and Torque of Coaxial Magnetic Gears

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