Permanent magnet circuit device

Abstract

The present invention provides a permanent magnetic circuit device. The permanent magnetic circuit device comprises a first magnet assembly, the first magnet assembly comprises a plurality of first permanent magnets and a plurality of first soft magnets, the plurality of first permanent magnets and the plurality of first soft magnets are connected to form a ring structure, and the plurality of first soft magnets are symmetrically arranged relative to the center of the ring structure. The present invention solves the problems of large amount of permanent magnets, high cost and unreasonable partitioning in the permanent magnetic device in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic equipment, and in particular to a permanent magnet magnetic circuit device. Background Art

[0002] The purpose of magnetic circuit design is to use the smallest magnet volume to generate a higher magnetic field strength in a specific magnetic field working air gap space. The optimal design of a permanent magnet mechanism is an inverse problem of magnetic field design. Given the spatial size of the design air gap, the optimal permanent magnet structure is designed.

[0003] A simple method for designing a permanent magnetic circuit is to place two pieces of permanent magnetic material parallel to each other to form the two poles of the magnet. A certain magnetic field is generated between the gaps of the two poles. In order to increase the field strength, people use soft magnetic materials with high magnetic permeability to stick to both ends of the permanent magnet to form a magnetic circuit with a yoke. Later, in order to further enhance the magnetic field, someone proposed the Halbach rotation theory and designed a hollow cylindrical magnet. The cylinder is divided into multiple magnet blocks, each of which is magnetized according to the direction of the Halbach rotation theory, and then assembled. The magnetic lines of force are constrained in the hole of the cylinder to form a high, approximately uniform magnetic field. Based on the Halbach rotation principle, magnetic circuit designs with different air gap shapes continue to emerge, using one or more magnetic circuits to superimpose at the working air gap to increase the magnetic field strength.

[0004] At present, in order to increase the magnetic field strength of the permanent magnetic field at the air gap, neodymium iron boron is often used as the magnet material, because of its high magnetic energy product and superior performance. However, neodymium iron boron is expensive, especially when the magnetic field needs to be strong, such as in the field of magnetic refrigeration, the magnetic field strength of permanent magnets is about 0.8T to 1.5T, especially when it is greater than 1.2T, the cost of the magnet will be very high, which is not conducive to commercialization. The existing traditional technology has the problem of large amount of permanent magnets and unreasonable block division.

[0005] That is to say, the permanent magnet device in the prior art has the problems of large amount of permanent magnets, high cost and unreasonable partitioning. Summary of the invention

[0006] The main purpose of the present invention is to provide a permanent magnet magnetic circuit device to solve the problems of large amount of permanent magnets, high cost and unreasonable partitioning in the permanent magnet device in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a permanent magnet magnetic circuit device is provided, including a first magnet assembly, the first magnet assembly including a plurality of first permanent magnets and a plurality of first soft magnets, the plurality of first permanent magnets and the plurality of first soft magnets are connected to form an annular structure, and the plurality of first soft magnets are symmetrically arranged relative to the center of the annular structure.

[0008] Furthermore, the annular structure has a set of magnetic pole pairs, there are two first soft magnetic bodies, and the two magnetic poles of the magnetic pole pair are located in the area where the two first soft magnetic bodies are located.

[0009] Furthermore, there are two basic magnetic circuits on both sides of the magnetic pole pair, one basic magnetic circuit is oriented counterclockwise and the other basic magnetic circuit is oriented clockwise, and the magnetization directions of the multiple first permanent magnets at the positions of the basic magnetic circuits constitute the directions of the basic magnetic circuits.

[0010] Furthermore, the magnetic field of the first soft magnetic body is smaller than the magnetic field of the first permanent magnet.

[0011] Furthermore, the first soft magnetic body is connected to the outer peripheral surface of the annular structure.

[0012] Furthermore, the plurality of first soft magnetic bodies have the same shape, are spaced apart around the circumference of the annular structure, and the distance between two adjacent first soft magnetic bodies is the same.

[0013] Furthermore, the permanent magnet magnetic circuit device also includes a second magnet assembly, which is cylindrical, and the annular structure is sleeved on the outside of the second magnet assembly and the two are concentric and spaced apart.

[0014] Furthermore, the second magnet assembly includes at least one second permanent magnet and at least one second soft magnet, and the second soft magnet and the second permanent magnet are spliced ​​into a cylindrical shape.

[0015] Furthermore, the annular structure has a plurality of magnetic pole pairs, and the two magnetic poles in each magnetic pole pair are symmetrically arranged relative to the center of the annular structure.

[0016] Furthermore, each magnetic pole pair has two basic magnetic circuits on both sides, one basic magnetic circuit is in a counterclockwise direction and the other basic magnetic circuit is in a clockwise direction, and the magnetization directions of the first permanent magnet and the second permanent magnet at the location of each basic magnetic circuit constitute the direction of the basic magnetic circuit.

[0017] Furthermore, the magnetic field of the second soft magnetic body is smaller than the magnetic field of the second permanent magnet.

[0018] Furthermore, both the annular structure and the cylindrical shape have a plurality of magnetic poles, and the magnetic poles on the annular structure and the cylindrical shape that are close to each other form a group of magnetic pole pairs, and the number of magnetic pole pairs is an even number.

[0019] Furthermore, there is one second permanent magnet, and there are multiple second soft magnetic bodies arranged in pairs. The multiple second soft magnetic bodies are symmetrically arranged relative to the center of the cylinder and connected to the outer peripheral surface of the cylinder.

[0020] Furthermore, the second permanent magnet has a plurality of gaps arranged at intervals in the circumferential direction, and a plurality of second soft magnetic bodies are filled in the plurality of gaps.

[0021] Furthermore, the number of the second soft magnetic bodies is two, and the number of the magnetic pole pairs is two groups.

[0022] Furthermore, the number of the first soft magnetic bodies is four, and two of the first soft magnetic bodies are arranged correspondingly to the two second soft magnetic bodies.

[0023] Furthermore, the second soft magnetic body is filled in the central hole surrounded by the second permanent magnet.

[0024] Furthermore, there are multiple second permanent magnets, and the multiple second permanent magnets are connected in sequence to form a permanent magnet ring, and the second soft magnet is filled in the central hole of the permanent magnet ring.

[0025] Furthermore, the number of the second permanent magnets is an even number; and / or the magnetization directions of all the second permanent magnets are different.

[0026] Furthermore, the number of the first soft magnetic bodies is four or six, and the number of the magnetic pole pairs is four or six.

[0027] Applying the technical solution of the present invention, the permanent magnet magnetic circuit device includes a first magnet assembly, the first magnet assembly includes multiple first permanent magnets and multiple first soft magnets, the multiple first permanent magnets and the multiple first soft magnets are connected to form an annular structure, and the multiple first soft magnets are symmetrically arranged relative to the center of the annular structure.

[0028] By connecting the first permanent magnet and the first soft magnet into a ring structure to form the first magnet assembly, the amount of the first permanent magnet is reduced without affecting the performance of the magnetic field of the first magnet assembly, greatly saving the production cost of the permanent magnetic circuit device. The plurality of first soft magnets are symmetrically arranged relative to the center of the ring structure, which facilitates the manufacture and design of the first magnet assembly and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 A schematic diagram showing the structure of a target magnet according to a first embodiment of the present invention is shown; and

[0031] Figure 2 A magnetic field distribution area diagram with magnetic field equipotential lines according to the first embodiment of the present invention is shown;

[0032] Figure 3 A magnetic field distribution area diagram with magnetic field equipotential lines and magnetic field contour lines according to the first embodiment of the present invention is shown;

[0033] Figure 4 A schematic structural diagram of a permanent magnetic circuit device according to Embodiment 1 of the present invention is shown;

[0034] Figure 5 A schematic diagram of the structure of a target magnet according to a second embodiment of the present invention is shown;

[0035] Figure 6 A schematic diagram showing the superposition of magnetic circuits of an equivalent permanent magnet according to the second embodiment of the present invention is shown;

[0036] Figure 7 A magnetic field distribution area diagram with magnetic field equipotential lines and magnetic field contour lines according to the second embodiment of the present invention is shown;

[0037] Figure 8 A schematic diagram showing the structure of one half of a permanent magnetic circuit device according to a second embodiment of the present invention is shown;

[0038] Fig. 9 A schematic structural diagram of a permanent magnetic circuit device according to a second embodiment of the present invention is shown;

[0039] Fig.10 A schematic diagram of the structure of a target magnet according to a third embodiment of the present invention is shown;

[0040] Fig.11 A schematic diagram showing the superposition of magnetic circuits of an equivalent permanent magnet according to the third embodiment of the present invention is shown;

[0041] Fig.12 A magnetic field distribution area diagram with magnetic field equipotential lines according to the third embodiment of the present invention is shown;

[0042] Fig.13 A magnetic field distribution area diagram with magnetic field equipotential lines and magnetic field contour lines according to the third embodiment of the present invention is shown;

[0043] Fig.14 A schematic diagram showing a quarter of the structure of a permanent magnetic circuit device according to Embodiment 3 of the present invention is shown;

[0044] Fig.15 A schematic structural diagram of a permanent magnetic circuit device according to a third embodiment of the present invention is shown;

[0045] Fig.16 A schematic diagram of the structure of a target magnet according to a fourth embodiment of the present invention is shown;

[0046] Fig.17 A schematic diagram showing the superposition of magnetic circuits of an equivalent permanent magnet according to a fourth embodiment of the present invention is shown;

[0047] Fig.18 A magnetic field distribution area diagram with magnetic field equipotential lines and magnetic field contour lines according to a fourth embodiment of the present invention is shown;

[0048] Fig.19 A schematic diagram showing one sixth of the structure of a permanent magnetic circuit device according to a fourth embodiment of the present invention is shown;

[0049] Fig. 20 A structural schematic diagram of a permanent magnet magnetic circuit device according to a fourth embodiment of the present invention is shown.

[0050] The above drawings include the following reference numerals:

[0051] 10. First magnet assembly; 11. First permanent magnet; 12. First soft magnet; 20. Second magnet assembly; 21. Second permanent magnet; 22. Second soft magnet; 30. Equivalent permanent magnet; 50. Magnetic field distribution area; 51. Sub-area; 60. Magnetic field equipotential lines; 70. Magnetic field contour lines; 100. Target magnet; 110. Target area. DETAILED DESCRIPTION

[0052] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0053] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0054] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0055] In order to solve the problems of large amount of permanent magnets, high cost and unreasonable partitioning in the permanent magnet device in the prior art, the present invention provides a permanent magnet magnetic circuit device.

[0056] like Figures 1 to 20 As shown, the permanent magnet magnetic circuit device includes a first magnet assembly 10, the first magnet assembly 10 includes multiple first permanent magnets 11 and multiple first soft magnets 12, the multiple first permanent magnets 11 and the multiple first soft magnets 12 are connected to form an annular structure, and the multiple first soft magnets 12 are symmetrically arranged relative to the center of the annular structure.

[0057] By connecting the first permanent magnet 11 and the first soft magnet 12 into a ring structure to form the first magnet assembly 10, the amount of the first permanent magnet 11 is reduced without affecting the performance of the magnetic field of the first magnet assembly 10, greatly saving the production cost of the permanent magnetic circuit device. The plurality of first soft magnets 12 are symmetrically arranged relative to the center of the ring structure, which facilitates the manufacture and design of the first magnet assembly 10 and reduces the production cost.

[0058] Specifically, the magnetic field of the first soft magnet 12 is smaller than the magnetic field of the first permanent magnet 11. In other words, the first soft magnet 12 is located at a position where the magnetic field strength is smaller in the first magnet assembly 10, so that the first soft magnet 12 does not affect the magnetic field strength of the first magnet assembly 10 and the working performance of the first magnet assembly 10, and the manufacturing cost of the first magnet assembly 10 can be saved.

[0059] exist Figure 4 , Fig. 9 , Fig.15 , Fig. 20 In the embodiment, the first soft magnetic body 12 is connected to the outer peripheral surface of the annular structure. Since the target magnetic field region generated by the first magnetic assembly 10 is located inside the annular structure, connecting the first soft magnetic body 12 to the outer peripheral surface of the annular structure does not affect the magnetic field strength in the target magnetic field region, which can effectively ensure the operation of the first magnetic assembly 10, and at the same time greatly save the production and manufacturing costs of the permanent magnetic circuit device, so that the permanent magnetic circuit device can better meet the needs of commercial production.

[0060] exist Figure 4 , Fig. 9 , Fig.15 , Fig. 20 In the embodiment, the plurality of first soft magnetic bodies 12 have the same shape, are arranged at intervals around the circumference of the annular structure, and the distance between two adjacent first soft magnetic bodies 12 is the same. This arrangement facilitates the production of the first soft magnetic bodies 12, and a plurality of first permanent magnets 11 are arranged between two adjacent first soft magnetic bodies 12, which facilitates the production of the first magnet assembly 10.

[0061] exist Fig. 9 , Fig.15 , Fig. 20 In the embodiment, the permanent magnet magnetic circuit device also includes a second magnet assembly 20, which is cylindrical, and the annular structure is sleeved on the outside of the second magnet assembly 20, and the two are concentric and spaced. This arrangement makes the area between the first magnet assembly 10 and the second magnet assembly 20 the area where the rotor moves. This double-cylinder nested form is preferably used as a magnetic field source in a magnetic refrigeration or magnetic heat pump unit. Magnetic refrigeration or magnetic heat pumps are achieved by periodically magnetizing and demagnetizing magnetocaloric materials based on the magnetocaloric effect, and refrigeration is achieved after multiple cycles, so a magnetization and demagnetization process is required. When the magnetic working fluid bed containing magnetocaloric material moves relative to the double-cylinder nested magnet in the annular air gap space, the magnetocaloric material can be periodically swept by the high magnetic field area and the low magnetic field area in the annular air gap, thereby achieving periodic magnetization and demagnetization.

[0062] exist Fig. 9 , Fig.15 , Fig. 20In the embodiment, the second magnet assembly 20 includes at least one second permanent magnet 21 and at least one second soft magnet 22, and the second soft magnet 22 and the second permanent magnet 21 are spliced ​​into a cylindrical shape. By arranging a plurality of second permanent magnets 21 and a plurality of second soft magnets 22 to be spliced ​​into a cylindrical shape, the magnetic field strength of the target area between the second magnet assembly 20 and the first magnet assembly 10 can be ensured, while the manufacturing cost of the second magnet assembly 20 is greatly saved.

[0063] Optionally, the annular structure has a plurality of magnetic pole pairs, and the two magnetic poles in each magnetic pole pair are symmetrically arranged relative to the center of the annular structure. There are two magnetic poles of different names in a pair of magnetic pole pairs, so that the magnetic field direction in the target area can be obtained. It should be noted that in the case of different magnetic pole pairs, the number and position of the first soft magnetic body 12 are different.

[0064] There are two basic magnetic circuits on both sides of each magnetic pole pair, one of which is in a counterclockwise direction and the other is in a clockwise direction, and the magnetization directions of the first permanent magnet 11 and the second permanent magnet 21 at the location of each basic magnetic circuit constitute the direction of the basic magnetic circuit. This arrangement allows the basic magnetic circuits on both sides of the magnetic pole pair to be superimposed at the magnetic pole pair, so that the magnetic field in the area of ​​the magnetic pole pair is the strongest.

[0065] Specifically, the magnetic field of the second soft magnet 22 is smaller than the magnetic field of the second permanent magnet 21. In other words, the second soft magnet 22 is located at a position in the second magnet assembly 20 where the magnetic field strength is smaller, so that the second soft magnet 22 does not affect the magnetic field strength of the second magnet assembly 20 and the working performance of the second magnet assembly 20, and the manufacturing cost of the second magnet assembly 20 can be saved.

[0066] Optionally, both the annular structure and the cylindrical shape have multiple magnetic poles, and the magnetic poles on the annular structure and the cylindrical shape that are close to each other form a set of magnetic pole pairs, and the magnetic pole pairs are an even number. This arrangement allows the magnetic poles in the first magnet assembly 10 and the second magnet assembly 20 to form magnetic pole pairs in one-to-one correspondence. In the case of the second magnet assembly 20, the number of magnetic pole pairs must be an even number to achieve periodic magnetization and demagnetization.

[0067] The materials of the first permanent magnet 11 and the second permanent magnet 21 include but are not limited to neodymium iron boron, samarium cobalt alloy, permanent ferrite, aluminum nickel cobalt, MnBi, samarium iron nitrogen, etc. At the same time, the solid arrow in the first permanent magnet 11 is the magnetic field direction of the first permanent magnet 11, and the solid arrow in the second permanent magnet 21 is the magnetic field direction of the second permanent magnet 21.

[0068] The materials of the first soft magnetic body 12 and the second soft magnetic body 22 include but are not limited to pure iron, low carbon steel, soft ferrite, silicon steel, industrial pure iron, iron-cobalt-vanadium alloy, Permalloy, etc. The first soft magnetic body 12 and the second soft magnetic body have low costs, which greatly reduces the production cost of the permanent magnetic circuit device.

[0069] Embodiment 1

[0070] In this embodiment, the permanent magnet circuit device only includes the first magnet assembly 10 .

[0071] exist Figures 1 to 4 In the specific embodiment shown in , the magnetic pole pair is a group, the first soft magnetic bodies 12 are two, and the two magnetic poles of the magnetic pole pair are located in the area where the two first soft magnetic bodies 12 are located. This arrangement ensures that the first soft magnetic body 12 does not affect the magnetic field strength and magnetic field direction in the target area, thereby ensuring the working stability of the first magnet assembly 10.

[0072] In this embodiment, there are two basic magnetic circuits on both sides of the magnetic pole pair, one of which is in a counterclockwise direction and the other is in a clockwise direction, and the magnetization directions of the multiple first permanent magnets 11 at the positions of the basic magnetic circuits constitute the direction of the basic magnetic circuits. This arrangement enables the basic magnetic circuits on both sides of the magnetic pole pair to be superimposed at the magnetic pole pair, so that the magnetic field in the area at the magnetic pole pair is the strongest.

[0073] It should be noted that the magnetization directions of two adjacent first permanent magnets 11 are different, so that the magnetization directions of multiple first permanent magnets 11 at the positions of each basic magnetic circuit can constitute the direction of the basic magnetic circuit. This embodiment is a new design optimization based on the traditional monopole cylindrical Halbach array.

[0074] First, the parameters of the target magnet 100 are determined.

[0075] exist Figure 1 In the specific embodiment shown, the target magnet 100 is a circular ring structure, the boundary of the target magnet 100 is the boundary of the circular ring structure, the number of magnetic pole pairs of the target magnet 100 is one pair, and the magnetic field direction of the target magnet 100 is the direction of the solid arrow in the figure.

[0076] Then, the parameters of the target area 110 are determined according to the parameters of the target magnet 100 .

[0077] exist Figure 1 In the specific embodiment shown, the center of the annular structure is the target area 110 , and the direction of the hollow arrow in the target area 110 is the direction of the magnetic field of the target area 110 .

[0078] Then, the target region 110 is equivalent to the equivalent permanent magnet 30 according to the parameters of the target region 110 , and the magnetic field distribution region 50 of the equivalent permanent magnet 30 is solved.

[0079] exist Figure 2 In the specific embodiment shown, the magnetic field distribution area 50 is distributed within the boundary of the target area 110 and the target magnet 100. Figure 2The magnetic field vector diagram in the figure mainly includes the magnitude and direction of the magnetic field vector and the drawn magnetic field equipotential lines. The magnetic field equipotential lines divide the boundary of the target magnet 100 into multiple sub-areas 51. By adjusting the density of the magnetic field equipotential lines 60, a suitable division result is found. The magnetic field equipotential lines 60 are approximated to straight lines by computer algorithms or other methods to perform regular division of the magnetic field area. For each divided area, the direction of the magnetic field vector is approximated by computer algorithms or other methods, so that each divided area has a consistent magnetic field direction.

[0080] exist Figure 3 In the specific embodiment shown, Figure 2 The magnetic field contour lines 70 are superimposed on the basis of the magnetic field contour lines 70, and the magnetic field design area is divided again to form sub-areas 51 by adjusting the density of the magnetic field contour lines 70. The magnetic field contour lines 70 are processed as approximate straight lines by computer algorithms or other methods to perform regular division of the magnetic field area, and the magnetic field vector size is approximated by computer algorithms or other methods for each divided area, so that the magnetic field size is consistent inside each divided area.

[0081] like Figure 4 As shown, through the previous steps, the spatial magnetic field design area is divided and regularized by magnetic field equipotential lines 60 and magnetic field contour lines 70 to obtain multiple sub-areas 51 with consistent internal magnetic field size and direction.

[0082] According to the reciprocity law, a first magnet assembly 10 with consistent internal magnetization direction and corresponding residual magnetism is designed. The soft magnetic material is replaced and optimized in the area with smaller magnetic field vector. Figure 3 In the diagram, the areas with smaller magnetic field vector magnitudes are the areas with smaller arrow lengths and lighter arrow colors. Figure 4 In the specific embodiment shown, a part of the permanent magnetic material is replaced by a soft magnetic material to form a first magnet assembly formed by splicing a first permanent magnet 11 and a first soft magnet 12 .

[0083] Of course, it is also possible to use ferrite and other permanent magnet materials with small remanence but low price to partially or completely optimize and replace the NdFeB permanent magnet materials in areas with smaller magnetic field vector sizes.

[0084] Preferably, the steps of the method can be implemented partially or consecutively by a computer program.

[0085] By using an objective function, such as the minimum permanent magnet volume or the minimum magnet cost as the objective function, an optimization algorithm is used to perform an optimal design to find the optimal sub-region 51 .

[0086] The optimization algorithm can be a genetic algorithm, a neural network algorithm, an ant colony algorithm, a simulated annealing algorithm, etc.

[0087] Embodiment 2

[0088] The difference from the first embodiment is that the permanent magnetic circuit device further includes a second magnet assembly 20

[0089] exist Figure 2 In the specific embodiment shown, there is one second permanent magnet 21, and there are multiple second soft magnets 22 arranged in pairs. The multiple second soft magnets 22 are symmetrically arranged relative to the center of the cylinder and connected to the outer peripheral surface of the cylinder. In this embodiment, the number of magnetic pole pairs is two, and the directions of the magnetic fields generated by the two magnetic pole pairs are the same. Setting one second permanent magnet 21 can satisfy the magnetic field generated by the two magnetic pole pairs, so as to ensure that the first magnet assembly 10 and the second magnet assembly 20 can work stably.

[0090] exist Figure 2 In the specific embodiment shown, the second permanent magnet 21 has a plurality of gaps arranged at intervals in the circumferential direction, and a plurality of second soft magnetic bodies 22 are filled in the plurality of gaps. Such an arrangement does not affect the magnetic field strength and magnetic field direction generated by the second permanent magnet 21, and can also reduce the amount of the second permanent magnet 21, thereby reducing the production cost of the second magnet assembly 20.

[0091] exist Figure 2 In the specific embodiment shown, the number of the second soft magnetic bodies 22 is two, and the number of the magnetic pole pairs is two groups. This arrangement can form two high magnetic field areas and two low magnetic field areas, thereby achieving periodic magnetization and demagnetization. It should be noted that Figure 2 In the region between the first magnet assembly 10 and the second magnet assembly 20, the region with hollow arrows is a high magnetic field region, and the region without hollow arrows is a low magnetic field region.

[0092] In this embodiment, the number of the first soft magnetic bodies 12 is four, and two of the first soft magnetic bodies 12 are arranged correspondingly to the two second soft magnetic bodies 22. In other words, in the double-cylinder type permanent magnetic circuit device with two pairs of magnetic poles, there are four areas with smaller magnetic fields on the first magnet assembly 10. The first soft magnetic body 12 does not affect the magnetic field strength generated by the first magnet assembly 10, greatly reducing the usage of the first permanent magnet 11 and greatly saving production costs.

[0093] First, the parameters of the target magnet 100 are determined.

[0094] exist Figure 5 In the specific embodiment shown, the target magnet 100 includes a magnetic ring and a magnetic column. The magnetic ring and the magnetic column are nested. The area of ​​the magnetic ring and the magnetic column is the boundary of the target magnet 100. The number of magnetic pole pairs of the target magnet 100 is two.

[0095] Then, the parameters of the target area 110 are determined according to the parameters of the target magnet 100 .

[0096] exist Figure 5 In the specific embodiment shown, the shaded portion is the boundary of the target magnet 100, and the annular area is the air gap area of ​​the designed magnetic field, in order to form two pairs of magnetic poles, that is to say, to form two high magnetic field areas, and also to alternate with two low magnetic field areas. The magnetic field designed in this embodiment is mainly used as a magnetic field source in a magnetic refrigerator. Magnetic refrigeration is achieved by periodically magnetizing and demagnetizing magnetocaloric materials based on the magnetocaloric effect, and multiple cycles are used to achieve refrigeration, so a magnetization and demagnetization process is required. The area with a hollow arrow in the annular area in the figure is the target area 110, and the direction of the hollow arrow is the direction of the magnetic field of the target area 110. The area with a hollow arrow is a high magnetic field area.

[0097] When the magnetic working fluid bed loaded with magnetocaloric material moves relative to the double-cylindrical magnet in the annular air gap space, the magnetocaloric material can be periodically swept by the high magnetic field area and the low magnetic field area in the annular air gap, thereby achieving periodic magnetization and demagnetization.

[0098] like Figure 5 As shown, the two-pair magnetic pole double-cylindrical magnetic field magnet assembly is mainly composed of a magnetic ring and a magnetic column, and a circular air gap space is formed between the magnetic ring and the magnetic column. The space area is initially divided into 4 blocks, of which there are 2 areas with hollow arrows, representing high magnetic field areas, or target areas 110, and the arrows thereon represent the magnetic field vector direction of the designed target area 110. Other areas represent low magnetic field or zero magnetic field areas. The high magnetic field area and the low magnetic field or zero magnetic field area are adjacent to each other.

[0099] Then, the target region 110 is equivalent to the equivalent permanent magnet 30 according to the parameters of the target region 110 , and the magnetic field distribution region 50 of the equivalent permanent magnet 30 is solved.

[0100] like Figure 6 As shown, it is a schematic diagram of the superposition of magnetic circuits of two equivalent permanent magnets 30. Through two basic annular magnetic circuits, two adjacent annular magnetic circuits are superimposed at the magnetic field design air gap. The characteristic is that the clockwise directions of the two adjacent magnetic circuits are opposite. In other words, when the reference magnetic circuit is clockwise, the magnetic circuit adjacent to it is counterclockwise.

[0101] Figure 7 for Figure 6 The magnetic field vector diagram and magnetic field equipotential line diagram of half of the magnetic field generated by the equivalent permanent magnet 30 in the target magnet 100 are obtained by numerical simulation methods or software such as finite element method. Figure 7 The magnetic field vector diagram mainly includes the magnitude and direction of the magnetic field vector, as well as the drawn magnetic field equipotential lines 60 and magnetic field contour lines 70.

[0102] exist Figure 7 In the specific embodiment shown, the magnetic field equipotential lines 60 and the magnetic field contour lines 70 divide the boundary of the target magnet 100 into a plurality of sub-regions 51. By adjusting the density of the magnetic field equipotential lines 60 and the magnetic field contour lines 70, a suitable division result is found, and the magnetic field equipotential lines 60 and the magnetic field contour lines 70 are approximated as straight lines by computer algorithms or other methods to perform regular division of the magnetic field region. For each divided sub-region 51, the direction of the magnetic field vector is approximated by computer algorithms or other methods, so that the interior of each divided sub-region 51 has a consistent magnetic field direction.

[0103] like Figure 8 As shown, through the previous steps, the spatial magnetic field design area is processed, and the magnetic field distribution area is divided and regularized by magnetic field equipotential lines 60 and magnetic field contour lines 70 to obtain multiple sub-areas 51 with consistent internal magnetic field size and direction.

[0104] According to the reciprocity law, the first magnet assembly 10 and the second magnet assembly 20 are designed to have the same internal magnetization direction and corresponding residual magnetization. The soft magnetic material is replaced and optimized in the area with smaller magnetic field vector. Figure 7 In the figure, the area with smaller magnetic field vector magnitude is the area with smaller arrow length and lighter arrow color. Figure 8 In the specific embodiment shown, a part of the permanent magnetic material is replaced by soft magnetic material, the first permanent magnet 11 and the first soft magnet 12 are spliced ​​into a first magnet assembly, and the second permanent magnet 21 and the second soft magnet 22 are spliced ​​into a second magnet assembly 20.

[0105] Figure 8 FIG. 1 is a design diagram of half of the present embodiment. By symmetrical arrangement, a complete first magnet assembly 10 and a second magnet assembly 20 can be obtained. Fig. 9 shown.

[0106] Preferably, the steps of the method can be implemented partially or consecutively by a computer program.

[0107] Through the objective function, such as the minimum permanent magnet volume or the minimum magnet cost as the objective function, the optimization algorithm is used to find the optimal design and find the optimal partition block. Different weights can also be set for multiple objectives to perform multi-objective parametric optimization design.

[0108] The optimization algorithm can be a genetic algorithm, a neural network algorithm, an ant colony algorithm, a simulated annealing algorithm, etc.

[0109] Embodiment 3

[0110] The difference from the second embodiment is that the number of magnetic pole pairs is different.

[0111] exist Figure 3 In the specific embodiment shown, the number of magnetic pole pairs is four, and the second soft magnetic body 22 is filled in the center hole surrounded by the second permanent magnet 21. In this embodiment, the magnetic field strength at the center of the second magnet assembly is the smallest, and filling the second soft magnetic body 22 in the center hole can effectively prevent the second soft magnetic body 22 from affecting the magnetic field strength generated by the second magnet assembly 20, while reducing the production cost of the second magnet assembly 20.

[0112] exist Figure 3 In the specific embodiment shown, there are multiple second permanent magnets 21, and the multiple second permanent magnets 21 are connected in sequence to form a permanent magnet ring, and the second soft magnet 22 is filled in the center hole of the permanent magnet ring. This arrangement allows the second permanent magnet 21 to cover the second soft magnet 22, avoiding the second permanent magnet 21 from generating a magnetic field at the center hole to interfere, and at the same time does not reduce the production cost of the second magnet assembly 20.

[0113] Optionally, the number of the second permanent magnets 21 is an even number. This arrangement makes the permanent magnet ring formed by the second permanent magnets 21 symmetrical, and part of the second permanent magnets 21 can be shared with adjacent magnetic pole pairs.

[0114] Specifically, the magnetization directions of all the second permanent magnets 21 are different. At the same time, the magnetic field direction of the permanent magnet ring formed by the plurality of second permanent magnets 21 is radially distributed to meet the requirements of the magnetic field generated by the four magnetic pole pairs.

[0115] In this embodiment, the number of the first soft magnetic bodies 12 is four, and the four first soft magnetic bodies 12 are located at positions corresponding to the positions of four magnetic pole pairs.

[0116] First, the parameters of the target magnet 100 are determined.

[0117] exist Fig.10 In the specific embodiment shown, the target magnet 100 includes a magnetic ring and a magnetic column. The magnetic ring and the magnetic column are nested. The area of ​​the magnetic ring and the magnetic column is the boundary of the target magnet 100. The number of magnetic pole pairs of the target magnet 100 is four.

[0118] Then, the parameters of the target area 110 are determined according to the parameters of the target magnet 100 .

[0119] exist Fig.10In the specific embodiment shown, the shaded portion is the boundary of the target magnet 100, and the annular area is the air gap area of ​​the designed magnetic field, in order to form four pairs of magnetic poles, that is to say, four high magnetic field areas are formed, and there are also four low magnetic field areas alternately. The magnetic field designed in this embodiment is mainly used as a magnetic field source in a magnetic refrigerator. Magnetic refrigeration is achieved by periodically magnetizing and demagnetizing magnetocaloric materials based on the magnetocaloric effect, and multiple cycles are used to achieve refrigeration, so a magnetization and demagnetization process is required. The area with a hollow arrow in the annular area in the figure is the target area 110, and the direction of the hollow arrow is the direction of the magnetic field of the target area 110. The area with a hollow arrow is a high magnetic field area.

[0120] When the magnetic working fluid bed loaded with magnetocaloric material moves relative to the double-cylindrical magnet in the annular air gap space, the magnetocaloric material can be periodically swept by the high magnetic field area and the low magnetic field area in the annular air gap, thereby achieving periodic magnetization and demagnetization.

[0121] like Fig.10 As shown, the two-pair magnetic pole double-cylindrical magnetic field magnet assembly is mainly composed of a magnetic ring and a magnetic column, and a circular air gap space is formed between the magnetic ring and the magnetic column. The space area is initially divided into 8 blocks, of which there are 4 areas with hollow arrows, representing high magnetic field areas, or target areas 110, and the arrows thereon represent the magnetic field vector direction of the designed target area 110. Other areas represent low magnetic field or zero magnetic field areas. The high magnetic field area and the low magnetic field or zero magnetic field area are adjacent to each other.

[0122] Then, the target region 110 is equivalent to the equivalent permanent magnet 30 according to the parameters of the target region 110 , and the magnetic field distribution region 50 of the equivalent permanent magnet 30 is solved.

[0123] like Fig.11 As shown, it is a schematic diagram of the superposition of magnetic circuits of four equivalent permanent magnets 30. Through four basic annular magnetic circuits, two adjacent annular magnetic circuits are superimposed at the magnetic field design air gap. Its characteristic is that the clockwise directions of the two adjacent magnetic circuits are opposite. In other words, when the reference magnetic circuit is clockwise, the magnetic circuit adjacent to it is counterclockwise.

[0124] Fig.12 for Fig.11 A quarter of the magnetic field vector diagram and magnetic field equipotential line diagram generated by the equivalent permanent magnet 30 in the figure. The magnetic field has a certain symmetry. A quarter of the cross-section area is taken to design the permanent magnetic circuit device, and the other areas can be mirrored in the same way. The magnetic field distribution generated by the equivalent permanent magnet 30 within the boundary of the target magnet 100 is solved by numerical simulation methods such as finite element or software. Fig.12 The magnetic field vector diagram mainly includes the magnitude and direction of the magnetic field vector, as well as the drawn magnetic field equipotential lines 60 and magnetic field contour lines 70.

[0125] exist Fig.12 In the specific embodiment shown, the magnetic field distribution area 50 is distributed within the boundary of the target area 110 and the target magnet 100. Fig.12 The magnetic field vector diagram in the figure mainly includes the magnitude and direction of the magnetic field vector and the drawn magnetic field equipotential lines. The magnetic field equipotential lines divide the boundary of the target magnet 100 into multiple sub-areas 51. By adjusting the density of the magnetic field equipotential lines 60, a suitable division result is found. The magnetic field equipotential lines 60 are approximated to straight lines by computer algorithms or other methods to perform regular division of the magnetic field area. For each divided area, the direction of the magnetic field vector is approximated by computer algorithms or other methods, so that each divided area has a consistent magnetic field direction.

[0126] exist Fig.13 The specific embodiment shown is in Fig.12 The magnetic field contour lines 70 are superimposed on the basis of the magnetic field contour lines 70, and the magnetic field design area is divided again to form sub-areas 51 by adjusting the density of the magnetic field contour lines 70. The magnetic field contour lines 70 are processed as approximate straight lines by computer algorithms or other methods to perform regular division of the magnetic field area, and the magnetic field vector size is approximated by computer algorithms or other methods for each divided area, so that the magnetic field size is consistent inside each divided area.

[0127] like Fig.14 As shown, through the previous steps, the spatial magnetic field design area is divided and regularized by magnetic field equipotential lines 60 and magnetic field contour lines 70 to obtain multiple sub-areas 51 with consistent internal magnetic field size and direction.

[0128] According to the reciprocity law, the first magnet assembly 10 and the second magnet assembly 20 are designed to have the same internal magnetization direction and corresponding residual magnetism. The soft magnetic material is replaced and optimized in the area with smaller magnetic field vector. Fig.13 In the diagram, the areas with smaller magnetic field vector magnitudes are the areas with smaller arrow lengths and lighter arrow colors. Fig.14 In the specific embodiment shown, a part of the permanent magnetic material is replaced by soft magnetic material, the first permanent magnet 11 and the first soft magnet 12 are spliced ​​into a first magnet assembly, and the second permanent magnet 21 and the second soft magnet 22 are spliced ​​into a second magnet assembly 20.

[0129] Fig.14 FIG. 1 is a design diagram of one quarter of the present embodiment. By symmetrical arrangement, a complete first magnet assembly 10 and a second magnet assembly 20 can be obtained. Fig.15 shown.

[0130] Preferably, the steps of the method can be implemented partially or consecutively by a computer program.

[0131] Through the objective function, such as the minimum permanent magnet volume or the minimum magnet cost as the objective function, the optimization algorithm is used to find the optimal design and find the optimal partition block. Different weights can also be set for multiple objectives to perform multi-objective parametric optimization design.

[0132] The optimization algorithm can be a genetic algorithm, a neural network algorithm, an ant colony algorithm, a simulated annealing algorithm, etc.

[0133] Embodiment 4

[0134] The difference from the third embodiment is that the number of magnetic pole pairs is different.

[0135] exist Figure 4 In the specific embodiment shown, the number of magnetic pole pairs is six, and the second soft magnetic body 22 is filled in the center hole surrounded by the second permanent magnet 21. In this embodiment, the magnetic field strength at the center of the second magnet assembly is the smallest, and filling the second soft magnetic body 22 in the center hole can effectively prevent the second soft magnetic body 22 from affecting the magnetic field strength generated by the second magnet assembly 20, while reducing the production cost of the second magnet assembly 20.

[0136] exist Figure 4 In the specific embodiment shown, there are multiple second permanent magnets 21, and the multiple second permanent magnets 21 are connected in sequence to form a permanent magnet ring, and the second soft magnet 22 is filled in the center hole of the permanent magnet ring. This arrangement allows the second permanent magnet 21 to cover the second soft magnet 22, avoiding the second permanent magnet 21 from generating a magnetic field at the center hole to interfere, and at the same time does not reduce the production cost of the second magnet assembly 20.

[0137] Optionally, the number of the second permanent magnets 21 is an even number. This arrangement makes the permanent magnet ring formed by the second permanent magnets 21 symmetrical, and part of the second permanent magnets 21 can be shared with adjacent magnetic pole pairs.

[0138] Specifically, the magnetization directions of all the second permanent magnets 21 are different. At the same time, the magnetic field direction of the permanent magnet ring formed by the plurality of second permanent magnets 21 is radially distributed to meet the requirements of the magnetic field generated by the six magnetic pole pairs.

[0139] In this embodiment, the number of the first soft magnetic bodies 12 is six, and the six first soft magnetic bodies 12 are located at positions corresponding to the six magnetic pole pairs.

[0140] First, the parameters of the target magnet 100 are determined.

[0141] exist Fig.16 In the specific embodiment shown, the target magnet 100 includes a magnetic ring and a magnetic column. The magnetic ring and the magnetic column are nested. The area of ​​the magnetic ring and the magnetic column is the boundary of the target magnet 100. The number of magnetic pole pairs of the target magnet 100 is six.

[0142] Then, the parameters of the target area 110 are determined according to the parameters of the target magnet 100 .

[0143] exist Fig.16 In the specific embodiment shown, the shaded portion is the boundary of the target magnet 100, and the annular area is the air gap area of ​​the designed magnetic field, in order to form six pairs of magnetic poles, that is to say, six high magnetic field areas are formed, and there are also six low magnetic field areas alternately. The magnetic field designed in this embodiment is mainly used as a magnetic field source in a magnetic refrigerator. Magnetic refrigeration is achieved by periodically magnetizing and demagnetizing magnetocaloric materials based on the magnetocaloric effect, and multiple cycles achieve refrigeration, so a magnetization and demagnetization process is required. The area with a hollow arrow in the annular area in the figure is the target area 110, and the direction of the hollow arrow is the direction of the magnetic field of the target area 110. The area with a hollow arrow is a high magnetic field area.

[0144] When the magnetic working medium bed containing magnetocaloric material moves relative to the double-cylindrical magnet in the annular air gap, the magnetocaloric material can be periodically swept by the high magnetic field area and the low magnetic field area in the annular air gap, thereby achieving periodic magnetization and demagnetization. Fig.10 As shown, the two-pair magnetic pole double-cylindrical magnetic field magnet assembly is mainly composed of a magnetic ring and a magnetic column, and a circular air gap space is formed between the magnetic ring and the magnetic column. The space area is initially divided into 12 blocks, of which there are 6 areas with hollow arrows, representing high magnetic field areas, or target areas 110, and the arrows thereon represent the magnetic field vector direction of the designed target area 110. Other areas represent low magnetic field or zero magnetic field areas. High magnetic field areas and low magnetic field or zero magnetic field areas are adjacent to each other.

[0145] Then, the target region 110 is equivalent to the equivalent permanent magnet 30 according to the parameters of the target region 110 , and the magnetic field distribution region 50 of the equivalent permanent magnet 30 is solved.

[0146] like Fig.17 As shown, it is a schematic diagram of the superposition of magnetic circuits of six equivalent permanent magnets 30. Through six basic annular magnetic circuits, two adjacent annular magnetic circuits are superimposed at the magnetic field design air gap. Its characteristic is that the clockwise directions of the two adjacent magnetic circuits are opposite. In other words, when the reference magnetic circuit is clockwise, the magnetic circuit adjacent to it is counterclockwise.

[0147] Fig.18 for Fig.11 The magnetic field vector diagram and magnetic field equipotential line diagram of one sixth of the magnetic field generated by the equivalent permanent magnet 30 in the figure. The magnetic field has a certain symmetry. A quarter of the cross-section area is taken to design the permanent magnetic circuit device, and the other areas can be mirrored in the same way. The magnetic field distribution generated by the equivalent permanent magnet 30 within the boundary of the target magnet 100 is solved by numerical simulation methods such as finite element or software. Fig.12The magnetic field vector diagram mainly includes the magnitude and direction of the magnetic field vector, as well as the drawn magnetic field equipotential lines 60 and magnetic field contour lines 70.

[0148] exist Fig.18 In the specific embodiment shown, the magnetic field equipotential lines 60 and the magnetic field contour lines 70 divide the boundary of the target magnet 100 into a plurality of sub-regions 51. By adjusting the density of the magnetic field equipotential lines 60 and the magnetic field contour lines 70, a suitable division result is found, and the magnetic field equipotential lines 60 and the magnetic field contour lines 70 are approximated as straight lines by computer algorithms or other methods to perform regular division of the magnetic field region. For each divided sub-region 51, the direction of the magnetic field vector is approximated by computer algorithms or other methods, so that the interior of each divided sub-region 51 has a consistent magnetic field direction.

[0149] like Fig.18 As shown, through the previous steps, the spatial magnetic field design area is processed, and the magnetic field distribution area is divided and regularized by magnetic field equipotential lines 60 and magnetic field contour lines 70 to obtain multiple sub-areas 51 with consistent internal magnetic field size and direction.

[0150] According to the reciprocity law, the first magnet assembly 10 and the second magnet assembly 20 are designed to have the same internal magnetization direction and corresponding residual magnetization. The soft magnetic material is replaced and optimized in the area with smaller magnetic field vector. Fig.18 In the figure, the area with smaller magnetic field vector magnitude is the area with smaller arrow length and lighter arrow color. Fig.19 In the specific embodiment shown, a part of the permanent magnetic material is replaced by soft magnetic material, the first permanent magnet 11 and the first soft magnet 12 are spliced ​​into a first magnet assembly, and the second permanent magnet 21 and the second soft magnet 22 are spliced ​​into a second magnet assembly 20.

[0151] Fig.19 FIG. 1 is a design diagram of half of the present embodiment. By symmetrical arrangement, a complete first magnet assembly 10 and a second magnet assembly 20 can be obtained. Fig. 20 shown.

[0152] Preferably, the steps of the method can be implemented partially or consecutively by a computer program.

[0153] Through the objective function, such as the minimum permanent magnet volume or the minimum magnet cost as the objective function, the optimization algorithm is used to find the optimal design and find the optimal partition block. Different weights can also be set for multiple objectives to perform multi-objective parametric optimization design.

[0154] The optimization algorithm can be a genetic algorithm, a neural network algorithm, an ant colony algorithm, a simulated annealing algorithm, etc.

[0155] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0156] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0157] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A permanent magnet magnetic circuit device, characterized in that: The invention comprises a first magnet assembly (10), wherein the first magnet assembly (10) comprises a plurality of first permanent magnets (11) and a plurality of first soft magnets (12), wherein the plurality of first permanent magnets (11) and the plurality of first soft magnets (12) are connected to form an annular structure, and the plurality of first soft magnets (12) are symmetrically arranged relative to the center of the annular structure; The annular structure has a set of magnetic pole pairs, the number of the first soft magnetic bodies (12) is two, and the two magnetic poles of the magnetic pole pair are located in the area where the two first soft magnetic bodies (12) are located; There are two basic magnetic circuits on both sides of the magnetic pole pair, one of which is in a counterclockwise direction and the other is in a clockwise direction, and the magnetization directions of the plurality of first permanent magnets (11) at the positions where the basic magnetic circuits are located constitute the directions of the basic magnetic circuits.

2. The permanent magnet circuit device according to claim 1, characterized in that: The magnetic field of the first soft magnetic body (12) is smaller than the magnetic field of the first permanent magnet (11).

3. The permanent magnet circuit device according to claim 1, characterized in that: The first soft magnetic body (12) is connected to the outer peripheral surface of the annular structure.

4. The permanent magnet circuit device according to claim 1, characterized in that: The plurality of first soft magnetic bodies (12) have the same shape, are arranged at intervals in the circumferential direction of the annular structure, and the distance between two adjacent first soft magnetic bodies (12) is the same.

5. The permanent magnet circuit device according to claim 1, characterized in that: The permanent magnet magnetic circuit device further comprises a second magnet component (20), the second magnet component (20) is cylindrical, the annular structure is sleeved on the outside of the second magnet component (20), and the two are concentric and spaced apart.

6. The permanent magnet circuit device according to claim 5, characterized in that: The second magnet assembly (20) comprises at least one second permanent magnet (21) and at least one second soft magnet (22), wherein the second soft magnet (22) and the second permanent magnet (21) are spliced ​​into the cylindrical shape.

7. The permanent magnet circuit device according to claim 6, characterized in that: The annular structure has a plurality of magnetic pole pairs, and the two magnetic poles in each magnetic pole pair are symmetrically arranged relative to the center of the annular structure.

8. The permanent magnet circuit device according to claim 7, characterized in that: There are two basic magnetic circuits on both sides of each magnetic pole pair, one of which is oriented counterclockwise and the other is oriented clockwise, and the magnetization directions of the first permanent magnet (11) and the second permanent magnet (21) at the positions of each basic magnetic circuit constitute the directions of the basic magnetic circuits.

9. The permanent magnetic circuit device according to claim 6, characterized in that: The magnetic field of the second soft magnet (22) is smaller than the magnetic field of the second permanent magnet (21).

10. The permanent magnet circuit device according to claim 6, characterized in that: The annular structure and the cylindrical shape both have a plurality of magnetic poles, and the magnetic poles on the annular structure and the cylindrical shape that are close to each other form a group of magnetic pole pairs, and the number of magnetic pole pairs is an even number.

11. The permanent magnetic circuit device according to claim 10, characterized in that: There is one second permanent magnet (21), and there are multiple second soft magnets (22) arranged in pairs. The multiple second soft magnets (22) are symmetrically arranged relative to the center of the cylinder and connected to the outer peripheral surface of the cylinder.

12. The permanent magnet circuit device according to claim 10, characterized in that: The second permanent magnet (21) has a plurality of gaps arranged at intervals in the circumferential direction, and a plurality of the second soft magnetic bodies (22) are filled in the plurality of gaps.

13. The permanent magnetic circuit device according to claim 10, characterized in that: The number of the second soft magnetic bodies (22) is two, and the number of the magnetic pole pairs is two groups.

14. The permanent magnetic circuit device according to claim 13, characterized in that: The number of the first soft magnetic bodies (12) is four, and two of the first soft magnetic bodies (12) and two of the second soft magnetic bodies (22) are arranged correspondingly.

15. The permanent magnetic circuit device according to claim 10, characterized in that: The second soft magnetic body (22) is filled in the central hole surrounded by the second permanent magnet (21).

16. The permanent magnetic circuit device according to claim 15, characterized in that: There are a plurality of second permanent magnets (21), and the plurality of second permanent magnets (21) are connected in sequence to form a permanent magnet ring, and the second soft magnet (22) is filled in the central hole of the permanent magnet ring.

17. The permanent magnetic circuit device according to claim 16, characterized in that: The number of the second permanent magnets (21) is an even number; and / or The magnetization directions of all the second permanent magnets (21) are different.

18. The permanent magnetic circuit device according to claim 16, characterized in that: The number of the first soft magnetic bodies (12) is four or six, and the number of the magnetic pole pairs is four or six.

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