Composite magnetic suspension motor

Abstract

The invention belongs to the technical field of magnetic suspension motors, and discloses a composite magnetic suspension motor, a stator of which comprises a first magnet yoke group and a second magnet yoke fixedly arranged on the first magnet yoke group, and the second magnet yoke is fixedly connected with all the first magnet yokes; a first driving coil group for driving the rotor to suspend and rotate is wound on an axial arm of the first magnet yoke; the rotor comprises a longitudinally arranged connecting shaft and a magnetic upper rotor and a magnetic lower rotor which are vertically arranged at the two ends of the connecting shaft, radial extension parts are outwards symmetrically arranged on the outer sides of the upper rotor and the lower rotor in the radial direction, a radially magnetized connecting magnet is embedded between every two adjacent radial extension parts, and the polarities of the connecting magnets located on the same horizontal plane are consistent; and the connecting shaft is made of a non-magnetic material. The radial extension parts and the connecting magnets on the rotor are alternately arranged, so that the magnetic field intensity and the magnetic field density of the rotor are greatly improved, and the operation stability and the control precision of the rotor are remarkably improved through the cooperation with the stator.

Description

Technical Field

[0001] The present invention relates to the technical field of compound magnetic levitation motors, and particularly to a compound magnetic levitation motor. Background Art

[0002] Magnetic levitation motors are divided into bearing magnetic levitation motors and shaftless magnetic levitation motors. The levitation force of bearing magnetic levitation motors is provided by separate electromagnetic bearings. Compared with traditional motors, shaftless magnetic levitation motors use stator windings and permanent magnet rotors to achieve active levitation control, no longer requiring additional magnetic levitation bearings. And because there is no mechanical contact between the rotor and the stator, the noise and wear during operation are small, the pollution is also less, and the operation efficiency and precision are higher. Therefore, they are widely used in various fields, such as semiconductor, health care, smart home, and industrial automation.

[0003] Currently, in order to achieve radial levitation control of the rotor in a magnetic levitation bearingless motor, in addition to the rotating winding, another set of levitation force windings is added to the stator winding of a compound magnetic levitation motor. The magnetic fields of the two sets of windings interact through the air gap to generate a radial force. Reasonable control of this force can achieve the levitation of the rotor, and the rotating torque of the motor is generated by the original torque winding, thus forming a bearingless permanent magnet motor. Its stator includes a plurality of longitudinally arranged magnetic yokes arranged around the rotor as the center, so that the magnetic force lines respectively pass through the closed magnetic circuits formed by the longitudinally arranged multiple groups of symmetrically arranged magnetic yokes and the permanent magnets on the corresponding rotor to form a rotating torque and a levitation torque. Currently, such motors can also be divided into reluctance motors, permanent magnet motors, and compound motors according to the type of rotor.

[0004] However, in practical applications, due to its traditional structural design, the above-mentioned existing compound magnetic levitation motors generally have problems of excessive magnetic leakage, poor magnetic collection effect, and low utilization rate of the spatial magnetic field.

[0005] Therefore, the existing technology needs to be further improved. Summary of the Invention

[0006] Aiming at the above problems, the present invention provides a compound magnetic levitation motor. The structure of the compound magnetic levitation motor is simple, the magnetic collection effect is good, the magnetic field utilization rate of the motor can be greatly improved, and the operation stability and reliability of the rotor can be improved.

[0007] To solve the above problems, the present application provides the following technical solutions: A composite magnetic levitation motor, comprising a rotor and a stator, the stator including: a first yoke group and an annular second yoke fixedly arranged in the middle of the first yoke group, the first yoke group being composed of a plurality of longitudinally arranged first yokes arranged in a circumferential pattern centered on the rotor, and the second yoke being fixedly connected to all the first yokes; the first yoke includes an axially arranged axial arm and a radially extending arm extending radially from at least one end of the axial arm, and a first drive coil group for driving the rotor to levitate and rotate is wound around the axial arm of the first yoke; the center of the annular second yoke is set to coincide with the rotor center axis of the rotor; The rotor includes a longitudinally arranged connecting shaft and an upper rotor and a lower rotor vertically arranged at both ends of the connecting shaft. A plurality of radially extending portions evenly distributed in the circumferential direction are symmetrically arranged radially outward on the outer sides of the upper rotor and the lower rotor respectively. The main bodies of the upper rotor and the lower rotor are made of a magnetically conductive material, and radially magnetized connecting magnets are embedded between adjacent radially extending portions. The polarities of the connecting magnets in the same horizontal plane are the same, and the connecting shaft is made of a non-magnetically conductive material.

[0008] In a first optional implementation manner, in the composite magnetic levitation motor, the radially extending portion is made of a magnetically conductive material, the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are symmetrically arranged up and down and their projections overlap, and the magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are opposite.

[0009] Optionally, in the composite magnetic levitation motor, the radially extending portion and the upper rotor / lower rotor are integrally designed, or the radially extending portion and the upper rotor / lower rotor are fixedly connected.

[0010] In a second optional implementation manner, in the composite magnetic levitation motor, the radially extending portion is made of a magnetically conductive material, the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are symmetrically arranged up and down and their projections overlap, and the magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are the same.

[0011] Specifically, the above-mentioned mover is applicable to a stator provided with a horizontal intermediate annular yoke.

[0012] In a third optional implementation manner, in the composite magnetic levitation motor, the radially extending portion is a radially magnetized magnet, and the magnetization direction of the radially extending portion is opposite to that of the adjacent connecting magnet; the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are symmetrically arranged up and down and their projections overlap, and the magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are opposite.

[0013] Specifically, the above-mentioned mover is applicable to a stator without a horizontal intermediate annular yoke, or is applicable to a stator provided with a non-magnetically conductive material intermediate annular connecting plate.

[0014] In the fourth optional embodiment, in the composite magnetic levitation motor, the radially extending portion is a magnet magnetized radially. The magnetization directions of the radially extending portion and the adjacent connecting magnet are opposite. The upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are symmetric up and down and are arranged with overlapping projections. The magnetization directions of the connecting magnets corresponding to the same positions on the upper rotor and the lower rotor are the same.

[0015] Specifically, the above-mentioned mover is applicable to a stator provided with a horizontally intermediate annular magnetic yoke for magnetic conduction. The magnetic circuit is divided into two separate upper and lower layers and is radially symmetric. Preferably, the radially extending portion and the connecting magnet are permanent magnets with the same shape.

[0016] In the fifth optional embodiment, in the composite magnetic levitation motor, the radially extending portion is a magnetic conductive material. The upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are arranged with an offset up and down.

[0017] Further preferably on the above basis, the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are offset by ° up and down, and the specifications of the radially extending portion and the connecting magnet are kept the same.

[0018] Optionally, in the composite magnetic levitation motor, the radially extending portion is a fan-shaped tooth-like structure, the connecting magnet is a fan-shaped ring structure, and the fan-shaped ring structure of the connecting magnet and the groove of the adjacent radially extending portion of the rotor are complementary in shape, and the upper rotor or the lower rotor in a disc shape is integrally formed.

[0019] Optionally, one of the installation methods of the rotor: the upper end of the connecting shaft is fixedly connected to the lower end face of the upper rotor, and the lower end of the connecting shaft is fixedly connected to the upper end face of the lower rotor; the connecting shaft is a hollow tubular structure, and a through hole is arranged in the middle; the main bodies of the upper rotor and the lower rotor are circular, and a central hole is arranged along the center of the upper rotor and the lower rotor to align with the through hole of the connecting shaft; Optionally, the second installation method of the rotor: the connecting shaft is a hollow tubular structure, and first plug-in portions are respectively arranged at the upper and lower ends of the connecting shaft, and second plug-in portions for plug-in cooperation with the first plug-in portions are arranged at the central positions of the upper rotor and the lower rotor; the first plug-in portion and the second plug-in portion are also adhesively cooperated.

[0020] Optionally, in the composite magnetic levitation motor, the second magnetic yoke is vertically connected to the axial arm of the first magnetic yoke; the center of the annular second magnetic yoke is set to coincide with the rotor center axis of the rotor; the second magnetic yoke is vertically connected to the middle position of the first magnetic yoke.

[0021] Optionally, in the composite magnetic levitation motor, radial arms respectively extend from the upper and lower ends of the axial arm of the first magnetic yoke.

[0022] Optionally, in the composite magnetic levitation motor, a second drive coil group for assisting in driving the rotor to suspend and rotate is wound around a portion of the second yoke located between two adjacent first yokes.

[0023] Optionally, each group of the second drive coil groups includes two coils, a suspension coil for the rotor suspension magnetic field and a rotation coil for providing a rotating magnetic field for the rotor; or each group of the second drive coil groups is one coil.

[0024] In an optional implementation manner, in the composite magnetic levitation motor, each first drive coil group is a coil that simultaneously provides a rotating magnetic field and a levitation magnetic field for the rotor, and the first drive coil group is arranged above the second magnetic yoke and / or below the second magnetic yoke. Optionally in another embodiment, in the composite magnetic levitation motor, each first drive coil group includes a levitation coil for providing a rotor levitation magnetic field and a rotating coil for providing a rotating magnetic field for the rotor.

[0025] On the basis of the above, specifically, each group of first drive coils is arranged above the second magnetic yoke and / or below the second magnetic yoke, or the suspension coil and the rotation coil of each group of drive coils are arranged at a position above or below the second magnetic yoke.

[0026] The present invention has the following beneficial effects: 1. The structure of the composite rotor is simple. By connecting the magnets and the radial extension, the magnetic field strength is improved, the magnetic circuit is optimized, the torque and axial stiffness of the rotor are improved, and the rotor has better working performance. In addition, there are multiple deformation schemes for the rotor. By cleverly setting the positions and magnetization directions of the permanent magnets on the upper rotor and the lower rotor, the magnetic circuit and magnetic field distribution are optimized, and the working efficiency and stability of the rotor are improved.

[0027] 2. The stator of the magnetic levitation motor adopts an annular second magnetic yoke to connect the magnetic circuits between the independent first magnetic yokes distributed in an annular shape, so that the leakage magnetic flux of each first magnetic yoke can be fully utilized through the connected annular magnetic yokes, thereby improving the magnetic collection effect of the stator, improving the utilization rate of the magnetic field, and then improving the working efficiency of the rotor; and when the rotor rotates from one first magnetic yoke to another first magnetic yoke, the magnetic field of the second magnetic yoke plays a higher transition, so that the magnetic field in the middle of the transition can be supplemented, and the rotor transitions more smoothly during the rotation process.

[0028] 3. The stator of the motor of the present invention is symmetrically distributed up and down with the second magnetic yoke as the center of symmetry. Therefore, during operation, there are closed-loop main magnetic paths that are symmetrically distributed up and down in the stator. These two main magnetic paths are respectively controlled by two sets of driving coil groups that are distributed up and down, so as to achieve independent control of the upper and lower parts of the rotor. In this way, not only can the axial position offset and radial offset of the rotor be adjusted, but it is more conducive to accurately adjusting the tilt angle of the rotor, realizing the transformation of the tilt angle and suspension control of the rotor from passive control to active control, thereby greatly improving the operation stability of the rotor. Due to the high stability of the rotor driven by this stator, the torque of the rotor can be significantly increased. The motor can increase the torque of the rotor by at least more than 10%.

[0029] 4. Through the cooperation of the first driving coil group and the second driving coil group, the stator of the magnetic levitation motor can achieve multi-dimensional regulation methods, making the regulation of the rotor more flexible and variable, and effectively improving the control accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic three-dimensional structure diagram of the composite magnetic levitation motor in Embodiment 1; Figure 2 Schematic top view structure diagram of the composite rotor in Embodiment 1; Figure 3 Schematic top view structure diagram of the stator in Embodiment 1; Figure 4 Schematic A-A cross-sectional structure diagram of the magnetic levitation motor in an embodiment of Embodiment 1; The arrowed lines represent magnetic field lines; Figure 5 Schematic diagram of the magnetic field line distribution from the top view angle of the upper rotor layer and the lower rotor layer of the motor in Embodiment 1; A is the top view of the upper rotor, and B is the top view of the lower rotor; Figure 6 Schematic A-A cross-sectional structure diagram of the magnetic levitation motor in Embodiment 2; The arrowed lines represent magnetic field lines; Figure 7 Schematic diagram of the magnetic field line distribution from the top view angle of the upper rotor layer and the lower rotor layer of the magnetic levitation motor in Embodiment 2; Figure 8 Schematic three-dimensional structure diagram of the composite rotor in Embodiment 3; Figure 9 Schematic diagram of the magnetic field line distribution from the top view angle of the upper rotor layer and the lower rotor layer of the magnetic levitation motor in Embodiment 3; Figure 10 Schematic A-A cross-sectional structure diagram of the magnetic levitation motor in Embodiment 3; The arrowed lines represent magnetic field lines; Figure 11 Schematic three-dimensional structure diagram of the magnetic levitation motor in Embodiment 4; Figure 12 Schematic diagram of the three-dimensional structure of the composite rotor in Embodiment 4; Figure 13 Schematic diagram of the magnetic field line distribution from a top-down perspective of the upper rotor layer and the lower rotor layer of the magnetic levitation motor in Embodiment 4; Figure 14 Schematic diagram of the A-A cross-sectional structure of the magnetic levitation motor in Embodiment 4; The arrowed lines represent magnetic field lines; Figure 15 Schematic diagram of the three-dimensional structure of the magnetic levitation motor in Embodiment 5; Figure 16 Schematic diagram of the A-A cross-sectional structure of the magnetic levitation motor in Embodiment 5; The arrowed lines represent magnetic field lines; Figure 17 Schematic diagram of the magnetic field line distribution from a top-down perspective of the upper rotor layer and the lower rotor layer of the magnetic levitation motor in Embodiment 5; Figure 18 A, B, C, and D are schematic diagrams of four different implementations of the stator of the magnetic levitation motor in Embodiment 6; The arrowed closed-loop routes in the figure represent the main magnetic circuit; Figure 19 Schematic diagram of the three-dimensional structure of the motor in Embodiment 7; Figure 20 Schematic diagram of the stator structure of the motor in Embodiment 7. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention. It should be noted that when an element is expressed as "fixed to" another element, it can be directly on the other element, or there can be one or more intermediate elements therebetween. When an element is expressed as "connected to" another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. The terms "vertical", "horizontal", "left", "right", "upper", "lower", "inner", "outer", "bottom", etc. used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in this specification in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items. In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Embodiment 1 As Figures 1 - 4 shown, this embodiment provides a composite maglev motor, which includes a rotor 1 and a stator 2. The stator includes: a first yoke group composed of a plurality of longitudinally arranged first yokes 21 arranged in a circle with the rotor as the center, and an annular second yoke 23 vertically and fixedly arranged in the middle of the first yoke group. The second yoke is fixedly connected to all the first yokes.

[0034] The rotor includes a non-magnetic connecting shaft 12 and an upper rotor 11 and a lower rotor 13 fixed at both ends of the connecting shaft.

[0035] The connecting shaft is made of non-magnetic material, such as plastic, aluminum alloy, copper alloy, stainless steel, etc. In this embodiment, the connecting shaft is a hollow or solid cylinder. This is because the suspension and rotation main magnetic circuits of the rotor do not need to be closed through this connecting piece.

[0036] In this embodiment, the number of radial extension parts on each rotor is 4, and the number of connecting magnets is also 4, with the same specifications. The specifications of the radial extension parts and the connecting magnets are kept the same. In other embodiments, the number of radial extension parts and connecting magnets on the upper and lower rotors can be reasonably adjusted, not limited to this embodiment.

[0037] In this embodiment, the radial extension part and the upper rotor / lower rotor body are integrally designed, or the radial extension part and the upper rotor / lower rotor body are fixedly connected by various existing methods.

[0038] In this embodiment, the rotor is a composite reluctance rotor. The circular bodies of the upper rotor and the lower rotor are made of soft magnetic material. A plurality of radially extending parts 111 evenly distributed in the circumferential direction are respectively arranged on the outer sides of the bodies of the upper rotor and the lower rotor along the radial arm direction at the top of the stator. The radial extension parts are also made of soft magnetic material. A radially magnetized connecting magnet 15 is embedded between adjacent radial extension parts 111. The radial magnetization of the connecting magnet means pointing towards or away from the axis along the radius direction of the rotor. The polarities of the connecting magnets in the upper rotor are the same, and the polarities of the connecting magnets in the lower rotor are the same.

[0039] The connecting magnets (permanent magnets) embedded in the adjacent radially extending portions of the rotor can provide an additional exciting magnetic field to enhance the torque of the motor. In addition, the connecting magnets can provide a basic magnetic field, endowing the rotor with polarity, enabling it to attract magnetically conductive materials. Together with the principle of minimum magnetic resistance, the axial stiffness can be further improved.

[0040] In this embodiment, the magnetization directions of the connecting magnets 15 at corresponding positions on the upper rotor and the lower rotor are the same, and the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor overlap vertically.

[0041] Moreover, the magnetization directions of the connecting magnets 15 at corresponding positions on the upper rotor and the lower rotor are the same. When the rotor configured in this way is combined with the stator of the annular second magnetic yoke, further optimization of the main magnetic circuit can be achieved.

[0042] In this embodiment, the radially extending portion is a fan-shaped tooth-like structure, and the connecting magnet 15 is a fan-shaped ring structure. The fan-shaped ring structure of the connecting magnet and the groove of the adjacent radially extending portion of the rotor are complementary in shape, and together they form a disk-shaped upper rotor or lower rotor. In other embodiments, the shapes of the radially extending portion and the connecting magnet can have other deformations, not limited to the drawings of this embodiment.

[0043] In other embodiments, the outer diameter of the fan-shaped ring connecting magnet is smaller than the outer diameter of the radially extending portion, and the fan-shaped ring magnet is recessed in the upper rotor or the lower rotor. Alternatively, in other embodiments, the thickness of the fan-shaped ring connecting magnet is smaller than that of the radially extending portion, and one surface of the two is located in a horizontal plane. These embodiments are all deformation schemes of this embodiment and fall within the protection scope of this application.

[0044] As Figure 1 and Figure 3 shown, compared with the existing stator structure, in the stator of this embodiment, an annular second magnetic yoke 23 is vertically arranged in the middle of the first magnetic yoke group. Such an arrangement not only enables the second magnetic yoke to be fixedly connected to all the first magnetic yokes, but also enables the adjacent originally independently arranged first magnetic yokes to achieve magnetic circuit connection through the second magnetic yoke.

[0045] During operation, two closed loops symmetrically distributed in the vertical and radial directions are formed among the second magnetic yoke where the main magnetic route coil is located, the upper / lower parts of the first magnetic yokes on the left and right sides of each driving coil group, and the corresponding radially extending portions. The upper and lower two closed main magnetic circuits share a magnetic path in the part of the second magnetic yoke.

[0046] In other embodiments, the position of the second yoke can be set above or below the middle of the axial arm of the first yoke and can be adjusted as needed. These deformation schemes all fall within the scope of protection of this application. This scheme can improve the adverse effects caused by the offset of the rotor center of gravity due to the load, such as rotor tilt. This is because the magnetic circuit of the offset end of the second yoke is shorter, the magnetic resistance is smaller, and the relative output force is larger, which can effectively balance the influence brought by the center of gravity offset.

[0047] In the stator of this embodiment, the first yoke includes an axially arranged axial arm 21a and a radially extending radial arm 21b from at least one end of the axial arm. A first drive coil group 22 for driving the rotor to levitate and rotate is wound around the axial arm of the first yoke.

[0048] The second yoke 23 is vertically connected to the axial arm of the first yoke; the center of the annular second yoke is set to coincide with the rotor center axis of the rotor. In this embodiment, further, the second yoke 23 is vertically connected to the middle of the axial arm of the first yoke, so that the stator is symmetrically arranged up and down with the second yoke as the central axis.

[0049] In this embodiment, the first yoke includes an axially arranged axial arm 21a and radially extending radial arms 21b respectively extending from the upper and lower ends of the axial arm to the rotor radius. The structure of the first yoke is in a similar C-shaped structure, and a first drive coil group 22 for driving the rotor to levitate and rotate is wound around the axial arm of the first yoke.

[0050] The stator using the above C-shaped first yoke is suitable for cooperating with the long-axis rotor of this embodiment. The upper and lower radial arms of the first yoke respectively correspond to the upper radial extension part and the lower radial extension part of the rotor, so as to form a closed magnetic circuit between the radial extension parts of two adjacent or non-adjacent long-axis rotors, the corresponding first yokes, and the second yoke part located between the two first yokes. The structure of this stator is simple, and the magnetic conductive backplane (used to facilitate the closed-loop setting of the magnetic circuit) provided at the bottom of the conventional stator can be omitted.

[0051] Specifically, in this embodiment, the number of the first yokes is 8, and the number of the rotor magnetic poles cooperating with it is 2, 4 or 6, etc.; in other embodiments, the number of the first yokes can also be 6, 10 or more, and the number of the radial extension parts of the rotor can be 2, 4 or 8; 2 or 4.

[0052] In this embodiment, in order to facilitate the installation of the second yoke and its connection with the first yoke and ensure that the magnetic lines of force can be connected between the second yoke and the adjacent first yoke, the following settings are made: The second yoke 23 is provided with a positioning hole for the axial arm of the first yoke to penetrate through, and the second yoke and the first yoke are fixedly connected, such as by bonding, screwing, welding or riveting and other fixed connection methods.

[0053] In other embodiments, the outer peripheral side wall / inner peripheral side wall of the second yoke is clamped and bonded to the inner side wall / outer side wall portion of the axial arm of the first yoke, or is fixedly connected in other ways.

[0054] The second yoke is composed of a plurality of second annular laminations laminated with each other along the lamination direction, and the lamination direction is set axially or radially. The first yoke is formed by laminating a plurality of first laminations along the lamination direction. The laminations can be made of silicon steel sheets.

[0055] In this embodiment, specifically, the second yoke is formed by a plurality of second annular laminations laminated up and down. The first yoke is formed by laminating a plurality of C-shaped first laminations back and forth. In other embodiments, the second yoke is formed by laminating a plurality of annular laminations arranged concentrically inside and outside.

[0056] In this embodiment, as Figure 3 shown, each first drive coil group includes a suspension coil 22a for the suspension magnetic field of the rotor and a rotation coil 22b for providing a rotation magnetic field for the rotor. In this embodiment, a set of the above-mentioned first drive coil groups 22 are respectively arranged above and below the second yoke. This method uses more coils, but has lower requirements for the control system. The suspension and rotation of the rotor can be independently controlled by controlling the suspension coil or the rotation coil respectively, and the control flexibility is higher.

[0057] Currently, in traditional longitudinally arranged yokes (or coil cores), due to their independent settings, during operation, in addition to forming a closed main magnetic path between the energized yoke and the corresponding rotor magnetic poles, the yoke will also release unused magnetic lines of force to the side directions other than the main magnetic path direction, resulting in relatively large magnetic leakage and low magnetic field utilization rate.

[0058] However, in the stator of the motor in this embodiment, since the annular second yoke connects the magnetic paths between the independent annularly distributed first yokes, during operation, the magnetic leakage to the side in each originally independent first yoke can form other magnetic paths through the connected annular yoke and be fully utilized, thereby improving the magnetic collection effect of the stator, increasing the utilization rate of the magnetic field, and further improving the working efficiency of the rotor.

[0059] On this basis, since the stator of this embodiment is symmetrically distributed up and down with the second yoke as the center of symmetry, during operation, there are closed-loop main magnetic paths symmetrically distributed up and down in the stator, and these two main magnetic paths are respectively controlled by two sets of first drive coil groups 22 distributed up and down, so as to realize the separate control of the rotation and suspension torques of the upper and lower parts of the rotor, and improve the controllability and stability of the rotor.

[0060] The working principle will be described below by taking the main magnetic circuit of the upper half of the motor stator as an example. The main magnetic circuit of the lower half of the stator is symmetrically arranged with that of the upper half, so it is omitted here.

[0061] Working principle of rotor rotation: As Figure 5 shown, at a certain moment, taking the rotating coils on two adjacent first yokes 21 as a group, at least two groups of adjacent rotating coils on the first yokes 21 that are not radially symmetric with the radial extension of the rotor are energized simultaneously. The magnetic force lines excited by the coils flow axially upward / downward in the first yoke. The main magnetic force lines pass through a first yoke, the corresponding upper / lower radial extension part, flow to the adjacent connecting magnet, then flow radially to the adjacent first yoke, and finally the magnetic circuit is closed through the second yoke part between the two first yokes, forming multiple upper closed magnetic circuits distributed left and right. Since the path of this magnetic circuit at the air gap is not the shortest distance, the rotor will rotate clockwise so that the magnetic force lines can be closed through the shortest distance. When the pair of first yokes is aligned with the upper radial extension part of the rotor they drive, the rotating coils on another pair of first yokes arranged at a 90° angle to this pair of first yokes work in the same way as above and pull the rotor to rotate clockwise again. According to the above rules, the rotating coils at the corresponding positions in the stator are energized in sequence, thus realizing the continuous rotation of the rotor. The two main magnetic circuits distributed up and down are radially symmetric. During the suspension process, opposite currents are passed through each pair of rotating coils and the magnetic circuit is closed through the transverse arm of the second yoke. The upper and lower double-layer counterpoint magnetic paths are radially symmetric. This control method can also use a structure with the upper and lower radial extensions offset. As long as the directions of the magnetic circuits flowing in the transverse yoke in the upper and lower layers are the same, the coordinated cooperation of the upper and lower magnetic circuits can be achieved. The rotational torque of the rotor can be increased by coordinately controlling the rotating coils of the upper half and the lower half of the stator, and the stability and accuracy of the rotor can be improved.

[0062] Working principle of rotor suspension: As Figure 4 shown, the suspension of the rotor in this embodiment is mainly achieved by generating a suction force between the first yoke and the rotor. When the suspension coils on each first yoke of the stator are energized and the current magnitude is adjusted so that the axial pulling force (magnetic resistance torque) on the rotor is equal, the rotor can achieve radial centered suspension. The distribution of the main magnetic force lines is the same as Figure 8 that.

[0063] In the motor of this embodiment, since a radially magnetized connecting magnet 15 is embedded between adjacent radially extending portions 111, the torque of the rotor is greatly increased and the axial stiffness is improved. The connecting magnet (permanent magnet) embedded in the adjacent radially extending portions of the rotor can provide an additional excitation magnetic field intensity to enhance the torque of the motor. In addition, the connecting magnet can provide a basic magnetic field, magnetize the rotor, attract ferromagnetic materials, and combined with the principle of minimum magnetic resistance, the axial stiffness is further improved. When the rotor has an axial displacement, the magnetic lines of force will be passively adjusted according to the principle of minimum magnetic resistance.

[0064] At a certain moment, when the top of the rotor has a radial offset, the suspension coil on the side with an increased air gap in the upper part of the stator will increase the current, increasing the attraction force on that side to correct the radial offset of the top of the rotor. Similarly, when the bottom of the rotor has a radial offset, the suspension coil on the side with an increased air gap in the lower part of the stator will increase the current, increasing the attraction force on that side to correct the radial offset of the bottom of the rotor.

[0065] In this embodiment, the rotor can independently adjust the radial offset of the upper or lower part of the rotor by controlling the coil current of the first magnetic yoke in the stator, thereby not only improving the controllability of the radial horizontal offset and the vertical axial position offset of the rotor, but also realizing the regulation of the tilt angle of the rotor, converting its original passive control into active control, and thus greatly improving the stability of the rotor during high-speed operation.

[0066] When the stability of the rotor is significantly improved, the stator can carry a larger working current during operation, significantly increasing the torque of the rotor. The stator of this application can increase the torque of the rotor by at least more than 10%.

[0067] In this embodiment, a connecting magnet is embedded between the radially extending portions of the original reluctance rotor. The connecting magnet provides an additional magnetic field for the rotor, causing magnetic field superposition under the electromagnetic field of the original stator coil. This not only significantly increases the magnetic field intensity, but also the improved main magnetic circuit of this embodiment is shorter, with smaller magnetic resistance, and the torque and axial stiffness of the rotor are significantly improved.

[0068] The motor further includes: a controller and a sensor that is control-connected to the controller. The sensor is used to detect the radial and axial positions and postures of the rotor, and the controller is used to regulate the current direction and magnitude of the first drive coil group and the second drive coil group.

[0069] For other structures provided inside the motor, reference can be made to the prior art.

[0070] Embodiment 2 Such as Figures 6 - 7As shown in the figure, this embodiment provides a composite magnetic levitation motor, which includes a stator and a rotor. The difference from Embodiment 1 lies in the setting of the rotor. The stator structure can be seen in Embodiment 1. The three-dimensional structure schematic diagram refers to Figure 1 .

[0071] In this embodiment, the composite rotor includes a connecting shaft 12 arranged longitudinally and upper and lower rotors 11 and 13 vertically arranged at both ends of the connecting shaft. The upper and lower rotors are coaxially arranged with the connecting shaft. The connecting shaft is made of non-magnetic material.

[0072] The main bodies of the upper and lower rotors are made of magnetic conductive material. The upper rotor extends radially outward along the main body to form a plurality of upper radial extension parts 111 evenly distributed in the circumferential direction. The lower rotor extends radially outward to form a plurality of lower radial extension parts 131 evenly distributed in the circumferential direction. The specifications of the upper and lower radial extension parts are the same, and the radial extension parts are made of magnetic conductive material.

[0073] In this embodiment, radially magnetized connecting magnets 15 are also fixedly embedded between adjacent radial extension parts. The radial magnetization of the connecting magnet 15 means pointing towards or away from the axis along the radius direction of the rotor. The polarities of the connecting magnets in the upper rotor are the same, and the polarities of the connecting magnets in the lower rotor are the same.

[0074] The difference from Embodiment 1 is as follows: In this embodiment, the upper radial extension part 111 of the upper rotor and the lower radial extension part 111 of the lower rotor are symmetric up and down and overlap in projection. The magnetization directions of the two connecting magnets 15 that overlap in position and projection on the upper and lower rotors are opposite.

[0075] Since the connecting shaft of the composite rotor in this embodiment is made of non-magnetic material, during operation, the main magnetic path does not pass through the connecting shaft, but passes through the upper radial arm of a first magnetic yoke of the stator, the adjacent radial extension part of the upper rotor, the adjacent connecting magnet, and the radial arm of another first magnetic yoke near the connecting magnet, and then flows axially downward along the longitudinal magnetic yoke to the radial extension part of the lower rotor and the adjacent connecting magnet, and finally passes through the lower radial arm of the corresponding other first magnetic yoke to complete the closed loop of the main magnetic path.

[0076] It can be seen that the main magnetic path of the stator in this embodiment is a closed-loop magnetic path that runs through the upper and lower parts of the stator. The second magnetic yoke plays a transitional role during the rotor switching operation, which can improve the smoothness of the rotor operation.

[0077] Rotating working principle: As Figure 7As shown, at a certain moment, the rotating coils of the two C-type first yokes that are not aligned with the radial extension of the rotor are energized at the same time, and the magnetic lines of force flow axially upward or downward at the same time. The magnetic lines of force pass through the first yoke, the radial extension of the upper rotor, the adjacent connecting magnet, and the radial arm of another adjacent first yoke, and then flow axially downward to the radial extension of the lower rotor, the adjacent connecting magnet, and finally flow back to the initial first yoke, completing the closed loop of the main magnetic circuit, forming two closed magnetic circuits distributed on the left and right. Since the path of the magnetic circuit at the air gap is not the shortest distance, the rotor will rotate counterclockwise so that the magnetic lines of force can be closed through the shortest distance. When the pair of C-type first yokes are aligned with the radial extension of the rotor pulled by them, the rotating coils on the other pair of C-type first yokes that are 90° different from the pair of C-type first yokes work in the same way as above, and pull the rotor again to rotate counterclockwise. According to this rule, the rotating coils are energized in sequence, thereby realizing the continuous rotation of the rotor. At the same time, the rotational drive can also be controlled by using two pairs of cross-shaped C-shaped yokes at the same time according to the above rules to enhance the rotational driving force.

[0078] How suspension works: Figure 6 As shown, when the suspension coils on the C-shaped magnetic yoke are energized and the current is adjusted to make the axial pulling force (magnetic drag torque) on the rotor equal, the rotor can achieve radially centered suspension. During the suspension process of the rotor, its two radial degrees of freedom are active suspension, and the remaining three degrees of freedom are passive suspension. The active suspension mechanism of the rotor is to increase the Maxwell force at the increased air gap to suppress radial deviation by adjusting the Maxwell force around the rotor. For example, at a certain moment, when the rotor deviates radially, the suspension coil on the side with increased air gap will increase the current, so that the attraction on that side increases to correct the radial deviation.

[0079] In this embodiment, although the second magnetic yoke does not directly play a major role in the main magnetic circuit, when the rotor rotates from one first magnetic yoke to another first magnetic yoke, the magnetic field of the second magnetic yoke plays a higher transition role, so that the magnetic field in the middle of the transition can be supplemented, and the rotor transitions more smoothly during rotation.

[0080] Example 3 This embodiment provides a composite magnetic levitation motor, which differs from the first embodiment in that: like Figure 8 As shown, the radial extension portion of the rotor used in the motor is a magnetic conductive material, the upper radial extension portion 111 of the upper rotor and the lower radial extension portion 111 of the lower rotor are staggered up and down, and the magnetization directions of the corresponding connecting magnets 15 on the upper and lower rotors are consistent.

[0081] In this embodiment, the upper radial extension portion 111 of the upper rotor and the lower radial extension portion 111 of the lower rotor are offset by 45° vertically, and the specifications of the radial extension portions and the connecting magnets are kept the same. Since there are a total of 8 magnetic poles on the rotor, each single piece is 45°, and the offset of 45° just results in opposite polarities.

[0082] This way of arranging the upper and lower rotors offset can make the rotor transition more smoothly during rotation and have smaller torque fluctuations. The main magnetic circuit distribution of this scheme is equivalent to that of the main magnetic circuit with the upper and lower rotors overlapping.

[0083] Figure 9 Shows the magnetic induction line distribution in the upper rotor and the lower rotor; Figure 10 Is the magnetic induction line distribution of the longitudinal section in the motor. The suspension principle and rotation principle of its rotor are the same as those in Embodiment 2, and will not be elaborated here.

[0084] Embodiment 4 As Figure 11 shown, in the composite magnetic levitation motor of this embodiment, it includes a rotor 1 and a stator 2. The stator structure can refer to Embodiment 1 and Embodiment 7, or other embodiments.

[0085] In this embodiment, the rotor is a composite reluctance rotor. On the outer sides of the upper rotor and the lower rotor of the rotor, a plurality of radially extending portions evenly distributed circumferentially are respectively arranged along the radial arm direction at the top of the stator. The main bodies of the upper rotor and the lower rotor are made of soft magnetic materials. Connecting magnets 15 magnetized radially are embedded between adjacent radially extending portions. The connecting shaft is made of non-magnetic material.

[0086] In this embodiment, in order to further optimize the structure, as Figure 12 shown, the radially extending portion 111 is also a magnet magnetized radially. The magnetization directions of the radially extending portion 111 and the adjacent connecting magnet 15 are opposite. The upper radially extending portion of the upper rotor and the corresponding lower radially extending portion of the lower rotor are symmetric up and down and overlap in projection. The magnetization directions of the connecting magnets 15 at corresponding positions on the upper rotor and the lower rotor are the same.

[0087] In this embodiment, the radially extending portion and the connecting magnet are permanent magnets with the same shape. The radially extending portion is a fan-shaped tooth-like structure, and the connecting magnet is a fan-shaped ring structure. The fan-shaped ring structure of the connecting magnet and the groove of the adjacent radially extending portion of the rotor are complementary in shape, and together form a disk-shaped upper rotor or lower rotor. The radial magnetization of the connecting magnet means pointing towards or away from the axis along the radius direction of the rotor.

[0088] Figure 14 Shows the magnetic induction line distribution in the upper rotor and the lower rotor; The magnetic induction line distribution of the longitudinal section in this motor is as Figure 13 shown. The magnetic circuit design, suspension principle and rotation principle of the rotor in the motor of this embodiment are similar to those in Embodiment 2, and will not be elaborated here.

[0089] Compared with the motor of Embodiment 1, in the motor of this embodiment, the radially extending portions and the connecting magnets with opposite magnetization directions on the rotor are alternately arranged, and the magnetization directions of the connecting magnets 15 corresponding to the upper and lower rotors are the same. This arrangement not only greatly improves the magnetic field intensity of the rotor, increases the magnetic field density per unit area, and shortens the main magnetic path, but also can significantly improve the torque and axial stiffness of the rotor. Moreover, since there are two independently controllable closed-loop main magnetic paths symmetrically distributed up and down in the stator and rotor, independent control of the rotational and levitation torques of the upper and lower parts of the rotor can be achieved, improving the stability and torque of the rotor.

[0090] Embodiment 5 As Figure 15 shown, this embodiment provides a composite magnetic levitation motor, which is different from that of Embodiment 2 in that: In the composite rotor, the radially extending portion 111 is a magnet with radial magnetization, and the magnetization directions of the radially extending portion and the adjacent connecting magnet are opposite, so that the magnetic force lines from the longitudinally arranged first magnetic yoke of the stator flow circumferentially along the rotor between the radially extending portion and the adjacent connecting magnet. In this embodiment, the radially extending portion and the connecting magnet are permanent magnets with the same shape.

[0091] In this embodiment, the magnetization directions of the connecting magnets 15 corresponding to the upper and lower rotors are opposite.

[0092] For other settings of the motor in this embodiment, refer to Embodiment 2.

[0093] Figure 17 shows the magnetic induction line distributions in the upper and lower rotors; Figure 16 is the magnetic induction line distribution of the longitudinal section in the motor. The levitation principle and rotation principle of the rotor in this motor are the same as those in Embodiment 4, and will not be elaborated here.

[0094] Compared with the rotor of Embodiment 2, the radially extending portions and the connecting magnets with opposite magnetization directions on the rotor of this embodiment are alternately arranged, which not only greatly improves the magnetic field intensity of the rotor, increases the magnetic field density per unit area, significantly reduces the magnetic resistance, improves the magnetic induction intensity of the rotor, but also significantly improves the torque and axial stiffness of the rotor.

[0095] Embodiment 6 This embodiment provides a magnetic levitation motor, which is different from that of Embodiment 1 in that: only one set of first drive coil groups 22 is wound on each first magnetic yoke 21, and this set of first drive coil groups 22 is located above or below the second magnetic yoke, as Figure 18 shown.

[0096] In the first implementation manner, as Figure 18 A andFigure 18 As shown in Fig. B, each of the first drive coil groups 22 includes a suspension coil 22a for the suspension magnetic field of the rotor and a rotating coil 22b for providing a rotating magnetic field for the rotor. The first drive coil group is located above or below the second yoke. This method uses more coils, but has lower requirements for the control system. The suspension and rotation of the rotor can be independently controlled by controlling the suspension coil or the rotating coil respectively, with higher control flexibility.

[0097] In the second embodiment, as Figure 18 shown in Fig. C, the first drive coil group 22 is a coil that simultaneously provides a rotating magnetic field and a suspension magnetic field for the rotor, and is arranged above or below the second yoke. In this setting, by controlling the coil on the first yoke, the rotating magnetic field and the suspension magnetic field provided by the stator for the rotor are adjusted simultaneously. This setting can simplify the coil arrangement and reduce the use cost of the coil, but has higher requirements for the control system of the stator.

[0098] In the third embodiment, as Figure 18 shown in Fig. D, the suspension coil 22a and the rotating coil 22b of each first drive coil group are respectively arranged above and below the second yoke. Specifically, the suspension coil 22a is arranged at the position above the second yoke of each first yoke, and the rotating coil 22b is arranged at the position below the second yoke of each first yoke. In other cases, the positions of the suspension coil 22a and the rotating coil 22b are set in reverse. For other structural settings of the motor in this embodiment, refer to Embodiment 1.

[0099] In this embodiment, the suspension of the rotor is controlled by the suspension coil located above the second yoke, and the rotation of the rotor is controlled by the rotating coil located below the second yoke. Such a setting can reduce the difficulty of controlling the suspension and rotation of the rotor. Since the suspension coil 22a and the rotating coil 22b of the above-mentioned first drive coil group are respectively arranged in the upper half and the lower half of the stator, the suspension main magnetic circuit and the rotating main magnetic circuit are respectively distributed in the upper half or the lower half of the stator. The working principle of the stator driving the mover to rotate and suspend also refers to Embodiment 1.

[0100] For the rotor structure of the motor in this embodiment and other structures of the stator, refer to Embodiment 1. Since the first drive coil group 22 in this embodiment is only arranged in the upper half or the lower half of the stator, its main magnetic circuit is only distributed in the upper half or the lower half, and the control method is not as flexible as that in Embodiment 1. The working principle of the stator driving the mover to rotate and suspend refers to Embodiment 1.

[0101] Embodiment 7 As Figure 19As shown in the figure, this embodiment provides a magnetic levitation motor obtained by improving the stator structure on the basis of Embodiments 1 to 6. The motor includes a rotor and a stator. The structure of the rotor can be referred to the foregoing embodiments.

[0102] As Figure 20 shown in the figure, the stator includes the aforementioned first yoke group and an annular second yoke 23 fixedly arranged on the first yoke group. The second yoke is connected to all the first yokes. The second yoke 23 is vertically connected to the middle of the axial arm of the first yoke. The center of the annular second yoke is set to coincide with the rotor center axis of the rotor. In this embodiment, the first yoke includes an axially arranged axial arm 21a and radial arms 21b radially extending from the upper and lower ends of the axial arm to the rotor. The structure of the first yoke is in a similar C-shaped structure, and a first drive coil group 22 for driving the rotor to levitate and rotate is wound on the axial arm of the first yoke. In this embodiment, each first drive coil group includes a levitation coil for the rotor levitation magnetic field and a rotation coil for providing a rotation magnetic field for the rotor.

[0103] On this basis, the improvement of the stator in this embodiment lies in that a second drive coil group 24 for assisting in driving the rotor to levitate and rotate is wound on the part (i.e., the connecting part) of the second yoke 23 located between two adjacent first yokes 21.

[0104] During operation, the first drive coil group 22 wound on the axial arm of the first yoke provides the main driving force for the levitation and suspension of the rotor, while the second drive coil group 24 arranged on the second yoke 23 plays an auxiliary adjustment role according to the state of the rotor, which is used to improve the control accuracy and stability of the rotor.

[0105] The specific principle is as follows: At a certain moment, for example, when the rotor as a whole has a radial offset, in addition to adjusting the current of the first drive coil, the current of the second drive coil on the side with a larger stator air gap can be increased, so that the auxiliary magnetic path generated by the second drive coil is in the same direction as the magnetic path of the first drive coil, strengthening the original magnetic field; thus increasing the attraction force on this side to correct the radial offset of the rotor at this place.

[0106] Or, the current of the second drive coil on the side with a smaller stator air gap can be reduced, so that the auxiliary magnetic path generated by the second drive coil is opposite to the magnetic path of the first drive coil, cutting the original magnetic field at this place, thereby reducing the radial offset of the rotor at this place.

[0107] In another case, when the rotor as a whole has an axial offset (such as dropping), the current of the corresponding second drive coil is increased to increase the axial suction force of the stator on the rotor, so that the rotor moves upward to correct its axial offset and improve the axial stiffness.

[0108] For other settings of the stator in this embodiment, reference may be made to Embodiment 1.

[0109] In the motors of other embodiments, the second driving coil group 24 on the second yoke can also provide the main driving force for the suspension and levitation of the rotor, and the first driving coil groups 22 distributed up and down on the axial arms of the first yoke are respectively used to independently and precisely assist in adjusting the upper and lower states of the rotor, significantly improving the stability and control accuracy of the rotor.

[0110] In the case where the stability of the rotor is significantly improved, the working current that the stator can carry is larger, and the torque of the rotor can be significantly increased.

[0111] It can be seen that due to the existence of two different driving coil groups in the motor of this embodiment, there are various adjustment methods for the stator, the control of the rotor is more flexible, variable, with more control dimensions, and the control accuracy and stability of the rotor are higher.

[0112] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood that for those of ordinary skill in the art, equivalent replacements or changes can be made according to the technical solution of the present invention and the concept of the present invention, and all such changes or replacements should fall within the protection scope of the appended claims of the present invention.

Claims

1. A composite magnetic levitation motor, comprising a rotor (1) and a stator (2), characterized in that: The stator comprises: a first yoke group and an annular second yoke (23) fixedly arranged on the first yoke group, the first yoke group comprising a plurality of first yokes (21) arranged longitudinally and arranged in a circumferential manner with the rotor as the center, the second yoke being fixedly connected to all the first yokes; the first yoke comprises an axial arm (21a) arranged longitudinally and a radial arm (21b) extending radially from at least one end of the axial arm to the rotor, the axial arm of the first yoke being wound with a first drive coil group (22) for driving the rotor to suspend and rotate; the center of the annular second yoke is arranged to coincide with the rotor center axis of the rotor; The rotor comprises a longitudinally arranged connecting shaft (12) and an upper rotor (11) and a lower rotor (13) arranged vertically at both ends of the connecting shaft. The outer sides of the upper rotor and the lower rotor are respectively provided with a plurality of radial extensions symmetrically arranged radially outward and evenly distributed in the circumferential direction. The main bodies of the upper rotor and the lower rotor are made of magnetically conductive material. Radially magnetized connecting magnets (15) are embedded between adjacent radially extending parts. The polarities of the connecting magnets on the same horizontal plane are consistent. The connecting shaft is made of non-magnetic conductive material.

2. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion is made of magnetically conductive material, the upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are vertically symmetrical and overlapped in projection, and the magnetization directions of the corresponding connecting magnets (15) on the upper rotor and the lower rotor are opposite.

3. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion and the upper rotor / lower rotor are designed as one piece, or the radial extension portion and the upper rotor / lower rotor are fixedly connected.

4. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion is made of magnetically conductive material, the upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are vertically symmetrical and overlapped in projection, and the magnetization directions of the corresponding connection magnets (15) on the upper rotor and the lower rotor are the same.

5. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion is a radially magnetized magnet, and the magnetization directions of the radial extension portion and the adjacent connecting magnet are opposite; the upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are symmetrical in upper and lower directions and overlap in projection, and the magnetization directions of the connecting magnets (15) at corresponding positions on the upper rotor and the lower rotor are opposite.

6. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion is a radially magnetized magnet, the magnetization directions of the radial extension portion and the adjacent connecting magnet are opposite, the upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are vertically symmetrical and projected overlappingly, and the magnetization directions of the connecting magnets (15) at corresponding positions on the upper rotor and the lower rotor are consistent.

7. The composite magnetic levitation motor according to claim 6, characterized in that: The radial extension and the connecting magnet are permanent magnets of identical shape.

8. The composite magnetic levitation motor according to claim 1, characterized in that: The radial extension portion is made of magnetic conductive material, and the upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are arranged in an upper and lower staggered manner.

9. The composite magnetic levitation motor according to claim 8, characterized in that: The upper radial extension portion (111) of the upper rotor and the lower radial extension portion (111) of the lower rotor are vertically offset by 45 degrees, and the specifications of the radial extension portion and the connection magnet are consistent.

10. The composite magnetic levitation motor according to claim 2, characterized in that: The radial extension portion is a fan-shaped tooth structure, and the connecting magnet is a fan-shaped ring structure. The connecting magnet of the fan-shaped ring structure and the groove of the adjacent radial extension portion of the rotor are complementary in shape, forming a disc-shaped upper rotor or lower rotor as a whole.

11. The composite magnetic levitation motor according to claim 1, characterized in that: The second magnetic yoke (23) is vertically connected to the axial arm of the first magnetic yoke; the center of the annular second magnetic yoke is arranged to coincide with the rotor center axis of the rotor; and the second magnetic yoke is vertically connected to the middle position of the first magnetic yoke.

12. The composite magnetic levitation motor according to any one of claims 1 to 11, characterized in that: Each first drive coil group is a coil that simultaneously provides a rotating magnetic field and a suspension magnetic field for the rotor, and the first drive coil group (22) is arranged above the second magnetic yoke and / or below the second magnetic yoke.

13. The composite magnetic levitation motor according to any one of claims 1 to 11, characterized in that: Each first driving coil group includes a suspension coil (22a) for providing a rotor suspension magnetic field and a rotation coil (22b) for providing a rotating magnetic field for the rotor.

14. The composite magnetic levitation motor according to claim 1, characterized in that: A second drive coil group (24) for adjusting the suspension and rotation state of the rotor is wound around a portion of the second magnetic yoke located between two adjacent first magnetic yokes.

15. The composite magnetic levitation motor according to claim 14, characterized in that: Each group of first drive coils (22) is arranged above the second magnetic yoke and / or below the second magnetic yoke, or the suspension coil (22a) and the rotation coil (22b) of each group of drive coils are arranged at a position above or below the second magnetic yoke.

16. The composite magnetic levitation motor according to claim 15, characterized in that: Each group of second drive coil groups (24) comprises two coils, a suspension coil for the rotor suspension magnetic field and a rotation coil for providing a rotating magnetic field for the rotor; or each group of second drive coil groups comprises one coil.

17. The composite magnetic levitation motor according to claim 16, characterized in that: Also includes: A controller and a sensor connected to the controller for control, wherein the sensor is used to detect the radial and axial positions of the rotor, and the controller is used to adjust the current direction and magnitude of the first drive coil group and the second drive coil group.

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