Halbach array rotor of axial coreless permanent magnet motor

Abstract

The invention discloses a Halbach array rotor of an axial coreless permanent magnet motor, which comprises two magnet yokes (1), 24 halbach array magnets (2) and a rotating shaft (3), the magnet yokes (1) are provided with 8 magnetic poles, and each magnetic pole comprises three axially arranged halbach array magnets (2); the two magnet yokes (1) are assembled along the axial direction by the rotating shaft (3), and periodic sinusoidal magnetic field distribution is formed between magnetic poles in the two magnet yokes. According to the technical scheme of the invention, by adopting the halbach array, the sinusoidal property of an air-gap magnetic field is improved, harmonic waves and edge effects are reduced, and the thickness of the magnet yoke is reduced to one third of that of the traditional magnet yoke.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of motor, in particular to a Halbach array rotor of an axial coreless permanent magnet motor. BACKGROUND

[0002] The axial permanent magnet motor has the advantages of compact structure, high efficiency and large power density, and obtains more and more attention, and is especially suitable for application in electric vehicles, renewable energy systems, gear energy storage systems and industrial equipment requiring high torque density and compact space.

[0003] However, the existing axial flux permanent magnet motor has the following disadvantages: 1, the rotor yoke is thick, and the eddy current loss is large; 2, the air gap magnetic field is poor in sinusoidal nature, and the harmonic is large; 3, the permanent magnet has edge effect, and the magnetic flux leakage is serious. SUMMARY

[0004] The present application provides a Halbach array rotor of an axial coreless permanent magnet motor, which adopts a Halbach array to improve the sinusoidal nature of the air gap magnetic field, reduce harmonics, reduce edge effects, and reduce the thickness of the yoke to one third of the traditional.

[0005] The embodiment of the present application provides a Halbach array rotor of an axial coreless permanent magnet motor, which comprises two yokes 1, 24 Halbach array magnets 2 and a rotating shaft 3. The yoke 1 is provided with eight magnetic poles, and each magnetic pole comprises three axially arranged Halbach array magnets 2. The rotating shaft 3 assembles the two yokes 1 along the axial direction, and a periodic sinusoidal magnetic field distribution is formed between the magnetic poles of the two yokes.

[0006] Optionally, the yoke is made of a material with high magnetic permeability.

[0007] Optionally, each magnetic pole is formed by three Halbach array magnets 2 with magnetizing directions of 0°, 60° and 120° to form a sinusoidal half-period magnetic field distribution.

[0008] Optionally, a non-magnetic isolation layer with a certain width is arranged between adjacent magnetic poles.

[0009] Optionally, the Halbach array magnet 2 is sintered NdFeb.

[0010] The present application provides a Halbach array rotor of an axial coreless permanent magnet motor, which has the following beneficial effects compared with the traditional structure: 1. The axial Halbach array improves the axial component of the air gap magnetic density by 30%; 2. The thickness of the yoke is reduced to one third of the traditional; 3. The eddy current loss of the yoke is reduced by two thirds. 4. The sinusoidal air-gap magnetic field is improved, the harmonic content is reduced, and the torque ripple is reduced to 4%. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 An axial cross-sectional view of a Halbach array rotor of an axial coreless permanent magnet motor is provided in the present application. Figure 2 A single-period magnet magnetization direction diagram is provided in the present application. Figure 3 A sinusoidal air-gap magnetic field distribution curve along the axial direction is provided in the present application. Figure 4 A finite element simulation axial magnetic field distribution cloud diagram is provided in the present application. DETAILED DESCRIPTION

[0012] The present application will be further described in conjunction with the drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not a limitation on the present application. In addition, it should be noted that only the parts related to the present application are shown in the drawings for ease of description. EMBODIMENT

[0013] Figure 1 An axial cross-sectional view of a Halbach array rotor of an axial coreless permanent magnet motor is provided in the present application. Referring to Figure 1 , the rotor includes 2 magnetic yokes 1, 24 Halbach array magnets 2, and 1 rotor shaft 3, and the Halbach array magnets 2 are fixed to the magnetic yoke 1 using non-magnetic materials.

[0014] In this embodiment, the Halbach array is arranged to form an axial multi-pole periodic alternating magnetic field distribution. Specifically, the magnetic yoke 1 is provided with 8 magnetic poles, each magnetic pole including 3 axially arranged Halbach array magnets 2.

[0015] The magnetic yoke 1 uses high permeability materials such as iron-based nanocrystalline alloy, pure iron, #10 steel, #20 steel, etc. High permeability materials have the advantages of high permeability, small magnetic resistance, and small eddy current loss.

[0016] Further referring to Figure 2 , each magnetic pole in this embodiment includes 3 axially arranged Halbach array magnets 2, and each magnetic pole forms a sinusoidal half-period magnetic field distribution by 3 Halbach array magnets 2 with magnetization directions of "0°→60°→120°". The magnetization direction of a pair of poles is "0°→60°→120°→180°→240°→300°".

[0017] Further, the Halbach array magnets 2 described above are sintered NdFeb.

[0018] A 1.5mm wide non-magnetic isolation layer is arranged between adjacent magnetic poles to suppress magnetic coupling.

[0019] The air gap length L in the embodiment is 1.1 times the magnet thickness T, so that the product of the air gap magnetic field strength B and the air gap length [d-2GG is the gap between the single-sided stator and the magnet] is maximized.

[0020] Referring to Figure 3 , the air gap magnetic field between the double rotors in the embodiment is axially sinusoidal.

[0021] The shaft 3 axially assembles the two magnetic yokes 1, and the magnetic poles between the two magnetic yokes form a periodic sinusoidal magnetic field distribution. Figure 4 The axial magnetic field distribution cloud chart for finite element simulation.

[0022] Further, when magnetizing and assembling, the same magnetic field direction magnet group is magnetized as a whole, and the permanent magnets are assembled according to the direction of the sinusoidal magnetic field change in the magnetic poles.

[0023] Note that the above is only the preferred embodiment of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A Halbach array rotor for an axial coreless permanent magnet motor, comprising two yokes (1), 24 Halbach array magnets (2), and one shaft (3), characterized in that: The magnetic yoke (1) is equipped with 8 magnetic poles, each magnetic pole including 3 axially arranged Halbach array magnets (2). The rotating shaft (3) assembles two magnetic yokes (1) along the axial direction, and a periodic sinusoidal magnetic field distribution is formed between the magnetic poles of the two magnetic yokes.

2. The Heilbeck array rotor of an axial coreless permanent magnet motor according to claim 1, characterized in that, The magnetic yoke is made of a material with high magnetic permeability.

3. The Heilbeck array rotor of an axial coreless permanent magnet motor according to claim 1, characterized in that, Each magnetic pole is formed by a sinusoidal half-cycle magnetic field distribution by three halbach array magnets with magnetization directions of 0°, 60° and 120° (2).

4. The Heilbeck array rotor of an axial coreless permanent magnet motor according to claim 1, characterized in that, A non-magnetic isolation layer of a certain width is provided between adjacent magnetic poles.

5. The Heilbeck array rotor of an axial coreless permanent magnet motor according to claim 1, characterized in that, The Halbach array magnet (2) is sintered NdFeB.

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