A halbach permanent magnet array

Abstract

The application provides a Halbach permanent magnet array which is formed by alternately arranging first permanent magnet blocks and second permanent magnet blocks; the upper part of the cross section of the first permanent magnet block is rectangular, the lower part is trapezoidal, and the waist of the trapezoid is a circular arc; the upper part of the cross section of the first permanent magnet block is symmetric about an axis with respect to the rectangular shape of the lower part; the upper part of the cross section of the second permanent magnet block is rectangular, and the lower part is a circular arc; the upper part of the cross section of the second permanent magnet block is symmetric about an axis with respect to the circular arc shape of the lower part; the first permanent magnet blocks are magnetized upward in the vertical direction, the second permanent magnet blocks are magnetized to the right in the horizontal direction, the first permanent magnet blocks are magnetized downward in the vertical direction, and the second permanent magnet blocks are magnetized to the left in the horizontal direction in sequence when being arranged, and four blocks form a magnetic field distribution period.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of permanent magnet array, in particular to a Halbach permanent magnet array. BACKGROUND

[0002] In 1979, Klaus Halbach, an American scholar, invented a special arrangement method of permanent magnet array, which is called Halbach array. In the Halbach permanent magnet array, due to the mutual superposition and offset of the magnetic fields, the magnetic field strength on one side of the permanent magnet array is greatly strengthened, and the magnetic field strength on the other side is greatly reduced. Under the condition of keeping the volume of the permanent magnet unchanged, the air gap density of the motor is improved by using the Halbach array.

[0003] At present, the Halbach permanent magnet array is mainly applied in high-speed motors, maglev trains, maglev plane motors, linear motors, magnetic bearings and medical fields. In order to obtain better control effect, some precision devices, such as linear motors that provide power for nanoscale positioning equipment, need to make the permanent magnet array provide a nearly perfect sinusoidal magnetic field, and the magnetic field generated by the ordinary Halbach permanent magnet array has a large gap with the perfect sinusoidal magnetic field. SUMMARY

[0004] Technical problem: In view of the problem that the magnetic field generated by the existing Halbach permanent magnet array has a large gap with the perfect sinusoidal magnetic field, the present application proposes a Halbach permanent magnet array to replace the rectangular cross-section magnetic block used in the ordinary Halbach array.

[0005] Technical scheme: In order to solve the above problems, the present application proposes a Halbach permanent magnet array, which is composed of first permanent magnet blocks and second permanent magnet blocks arranged alternately; the upper part of the cross-section of the first permanent magnet block is rectangular, the lower part is trapezoidal, and the waist of the trapezoid is a circular arc; and the length of the rectangle and the upper side length of the trapezoid are both a; the lower side length of the trapezoid is L, the upper part of the cross-section of the first permanent magnet block is symmetric about the axis with the rectangle and the trapezoid, and the circular arc of the lower trapezoid is located on the circle with L / 2 as the radius and tangent to the lower side and the axis of symmetry; the upper part of the cross-section of the second permanent magnet block is rectangular, the lower part is circular arc, and the length of the rectangle is L-a; the lower circular arc of the cross-section of the second permanent magnet block is located on the circle with the center of the upper part of the rectangle as the center and the radius of L / 2; the upper part of the cross-section of the second permanent magnet block is symmetric about the axis with the rectangle and the circular arc; when arranged, the first permanent magnet block with vertical upward magnetization, the second permanent magnet block with horizontal right magnetization, the first permanent magnet block with vertical downward magnetization, and the second permanent magnet block with horizontal left magnetization are arranged in the order of close contact, and every four blocks constitute a magnetic field distribution period.

[0006] Further, the height of the first permanent magnet block cross section is

[0007] Further, the range of a is

[0008] Further, the circular arc waist of the lower trapezoidal shape of the first permanent magnet block cross section is half of the lower circular arc of the second permanent magnet block cross section.

[0009] Further, the height of the second permanent magnet block cross section is

[0010] Beneficial effects: compared with the prior art, the technical scheme of the application has the following beneficial technical effects:

[0011] The permanent magnet array proposed in the application greatly enhances the magnetic field on one side and greatly weakens the magnetic field on the other side, has high spatial utilization rate of the magnetic field, high uniformity and less magnetic flux leakage. The side with strong magnetic field is used to generate Lorentz magnetic force for driving the motor. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Structure cross-sectional view of the embodiment of the application composed of 9 permanent magnets;

[0013] Figure 2 Permanent magnet cross-sectional size relationship diagram;

[0014] Figure 3 The novel Halbach array of the application has magnetic field line distribution diagram;

[0015] Figure 4 Comparison diagram of the magnetic flux density in the X and Y directions of the ordinary Halbach array and the novel Halbach array permanent magnet array at the time of 0.4mm from the lower surface of the magnetic array;

[0016] Figure 5 Comparison diagram of the magnetic flux density in the X and Y directions of the ordinary Halbach array and the novel Halbach array permanent magnet array at the time of 0.6mm from the lower surface of the magnetic array;

[0017] Figure 6 Schematic diagram of a linear motor example composed of a novel Halbach permanent magnet array;

[0018] Figure 7 Schematic diagram of a magnetic levitation plane motor example composed of a novel Halbach permanent magnet array. DETAILED DESCRIPTION

[0019] The present application provides a Halbach permanent magnet array, which is formed by alternately arranging first permanent magnet blocks and second permanent magnet blocks; the first permanent magnet block has a rectangular upper part and a trapezoidal lower part in cross section, and the waist of the trapezoidal lower part is a circular arc; the length of the rectangular upper part and the upper side length of the trapezoidal lower part are both a; the lower side length of the trapezoidal lower part is L, the rectangular upper part and the trapezoidal lower part of the first permanent magnet block are symmetric about an axis, and the circular arc of the trapezoidal lower part is located on a circle with a radius of L / 2 and tangent to the axis of symmetry; the second permanent magnet block has a rectangular upper part and a circular arc lower part in cross section, and the length of the rectangular upper part is L-a; the circular arc of the second permanent magnet block is located on a circle with a center at the center of the upper side length of the rectangular upper part and a radius of L / 2; the rectangular upper part and the circular arc lower part of the second permanent magnet block are symmetric about an axis; the first permanent magnet block is magnetized upward in the vertical direction, the second permanent magnet block is magnetized to the right in the horizontal direction, the first permanent magnet block is magnetized downward in the vertical direction, and the second permanent magnet block is magnetized to the left in the horizontal direction, and the four blocks are arranged in the above order to form a magnetic field distribution period.

[0020] The height of the cross section of the first permanent magnet block is

[0021] The range of a is

[0022] The circular arc waist of the trapezoidal lower part of the first permanent magnet block is half of the lower circular arc of the second permanent magnet block.

[0023] The height of the cross section of the second permanent magnet block is

[0024] The cross sections of the first and second magnetic blocks are as shown in Figure 2 , Figure 1 An example of 9 permanent magnets, which can generate periodic sinusoidal magnetic fields. Figure 4 and Figure 5 are respectively the comparison chart of the magnetic flux density in the X and Y direction components of the ordinary Halbach array and the new Halbach array permanent magnet array at a distance of 0.4mm from the lower surface of the magnetic array when , and the comparison chart of the magnetic flux density in the X and Y direction components of the ordinary Halbach array and the new Halbach array permanent magnet array at a distance of 0.6mm from the lower surface of the magnetic array when .

[0025] Figure 3 The magnetic field distribution diagram of the new Halbach array of the present application can be seen from the figure that the magnetic field density below the magnet array is obviously greater than the magnetic field density above. Figure 4For the new Halbach array and the electromagnetic thrust of the lower coil, in the case of fixed coil, by controlling the coil current change, so that the permanent magnet array does linear motion. Figure 5 For the magnetic levitation planar motor using the new Halbach permanent magnet array, the stator part is composed of X and Y direction wire layer. By controlling the current of the lower wire, the mover composed of four new Halbach permanent magnet arrays realizes six degrees of freedom positioning control.

Claims

1. A Halbach permanent magnet array, characterized in that, The permanent magnet array is formed by alternately arranging first permanent magnet blocks and second permanent magnet blocks; the first permanent magnet block has a rectangular upper portion and a trapezoidal lower portion in cross section, the waist of the trapezoidal lower portion is an arc, the length of the rectangular upper portion and the length of the upper side of the trapezoidal lower portion are both a, the length of the lower side of the trapezoidal lower portion is L, the rectangular upper portion and the trapezoidal lower portion are symmetric about an axis, and the arc of the trapezoidal lower portion is located on a circle with a radius of L / 2 and tangent to the lower side and the axis of symmetry; the second permanent magnet block has a rectangular upper portion and an arc-shaped lower portion in cross section, the length of the rectangular upper portion is L-a, and the arc of the lower portion is located on a circle with a center at the center of the upper side of the rectangular upper portion and a radius of L / 2; the rectangular upper portion and the arc-shaped lower portion of the second permanent magnet block are symmetric about an axis; the first permanent magnet blocks are magnetized upward in the vertical direction, the second permanent magnet blocks are magnetized to the right in the horizontal direction, the first permanent magnet blocks are magnetized downward in the vertical direction, and the second permanent magnet blocks are magnetized to the left in the horizontal direction in sequence, and four blocks form a magnetic field distribution period.

2. A Halbach permanent magnet array according to claim 1, wherein, The height of the first permanent magnet block cross section is 3. A Halbach permanent magnet array according to claim 1 or 2, wherein, The range of a is 4. A Halbach permanent magnet array according to claim 1 or 2, wherein, The arc-shaped waist of the trapezoidal lower portion of the first permanent magnet block is half of the arc of the lower portion of the second permanent magnet block.

5. A Halbach permanent magnet array according to claim 1 or 2, wherein, The height of the second permanent magnet block cross section is

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