Composite magnetic suspension bearingless motor

Abstract

The invention belongs to the technical field of magnetic suspension motors, and discloses a composite magnetic suspension bearingless motor, a stator of the composite magnetic suspension bearingless motor comprises a first magnet yoke group and an annular second magnet yoke fixed on the first magnet yoke group, and the first magnet yoke group is composed of a plurality of first magnet yokes; driving coil groups for driving the rotor to suspend and rotate are wound on the second magnet yokes; a rotor comprises a longitudinally-arranged non-magnetic-conductive connecting shaft, an upper rotor and a lower rotor, the outer sides of the upper rotor and the lower rotor are respectively, outwards and symmetrically provided with a plurality of radial extending parts which are uniformly distributed in the circumferential direction in the radial direction, the main bodies of the upper rotor and the lower rotor are made of magnetic-conductive materials, and a radially-magnetized connecting magnet is embedded between every two adjacent radial extending parts. And the connecting magnets on the same horizontal plane are consistent in polarity. According to the motor, the stator and the composite rotor are matched, the space utilization rate of the motor is higher, the manufacturing cost is lower, the magnetic field utilization rate is high, and the operation efficiency and reliability of the motor are guaranteed.

Description

Technical Field

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

[0002] Due to the combination of the advantages of magnetic levitation technology and bearingless motors, magnetic levitation motors achieve contactless, low-friction, and high-precision operation of the rotor, and thus are widely used in technical fields such as industrial automation, semiconductors, healthcare, and smart homes. The working principle of a magnetic levitation bearingless motor is based on the magnetic force provided by the energized stator windings to drive the rotor to rotate and levitate. The stator includes a plurality of longitudinally arranged 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 yokes and the permanent magnets on the corresponding rotor to form a rotating torque and a levitation torque. The types of rotors include reluctance type, permanent magnet type, and composite rotors, etc.

[0003] However, the stators of current magnetic levitation motors generally have a relatively complex structure. For example, in the magnetic levitation motor with the publication number CN112865609A, as Figure 1 shown, in the stator assembly, the levitation coil and the drive coil are both arranged on the inverted L-shaped second iron core (i.e., yoke). With such a stator, the number of coils installed is large, the volume is huge, and in order to reserve enough space for the coils, the stator has a large volume, and there are also problems of low utilization rate of the electromagnetic field of the coils and poor magnetic flux collection effect. Moreover, the traditional rotors used also have problems of small torque and insufficient axial stiffness, resulting in low operating efficiency of the motor.

[0004] Therefore, the prior art needs to be further improved. Summary of the Invention

[0005] In view of the above problems, the present invention provides a composite magnetic levitation bearingless motor. The motor uses a stator with a more compact structure, fewer coils, and better magnetic flux collection effect in cooperation with a composite rotor, which not only has higher space utilization rate and lower manufacturing cost of the motor, but also has a high magnetic field utilization rate, improving the operating efficiency and reliability of the motor.

[0006] To solve the above problems existing in the prior art, the present application provides the following technical solutions: A composite magnetic levitation bearingless motor, comprising: a rotor and a stator, the stator comprising: a first yoke group and an annular second yoke vertically fixed on the first yoke group, the first yoke group being composed of a plurality of longitudinally arranged first yokes arranged in a circumferential arrangement around the rotor as the center, the second yoke being fixedly connected to all the first yokes; drive coil groups for driving the rotor to levitate and rotate are wound on the portions of the second yoke located between two adjacent first yokes; The rotor includes a non-magnetic connecting shaft arranged longitudinally and an upper rotor and a lower rotor vertically arranged at both ends of the connecting shaft. On the outer sides of the upper rotor and the lower rotor, a plurality of radially extending parts evenly distributed in the circumferential direction are symmetrically arranged radially outward. The main bodies of the upper rotor and the lower rotor are made of magnetic conductive materials. Connecting magnets magnetized radially are embedded between adjacent radially extending parts, and the polarities of the connecting magnets in the same horizontal plane are the same.

[0007] Optionally, in the composite magnetic suspension bearingless 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.

[0008] Optionally, in the composite magnetic suspension bearingless motor, radial arms extend from the upper and lower ends of the axial arm of the first magnetic yoke respectively.

[0009] Optionally, in the composite magnetic suspension bearingless motor, each drive coil group includes a suspension coil for the suspension magnetic field of the rotor and a rotation coil for providing a rotation magnetic field for the rotor; or, each drive coil group is a coil that simultaneously provides a rotation magnetic field and a suspension magnetic field for the rotor.

[0010] Optionally, in the composite magnetic suspension bearingless motor, the second magnetic yoke is composed of a plurality of second annular laminations laminated in the lamination direction, and the lamination direction is set axially or radially.

[0011] In the first optional rotor implementation manner, the radially extending parts are made of magnetic conductive materials. The upper radially extending part of the upper rotor and the lower radially extending part of the lower rotor are symmetric up and down and their projections overlap. The magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are opposite.

[0012] In the second optional rotor implementation manner, the radially extending parts are made of magnetic conductive materials. The upper radially extending part of the upper rotor and the lower radially extending part of the lower rotor are symmetric up and down and their projections overlap. The magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are the same.

[0013] In the third optional rotor implementation manner, the radially extending parts are magnets magnetized radially, and the magnetization directions of the radially extending parts and the adjacent connecting magnets are opposite; the upper radially extending part of the upper rotor and the lower radially extending part of the lower rotor are symmetric up and down and their projections overlap. The magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are opposite.

[0014] In an optional fourth rotor embodiment, the radially extending portion is a magnet magnetized radially, and 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, and the magnetization directions of the connecting magnets at corresponding positions on the upper rotor and the lower rotor are the same.

[0015] Optionally, in the composite magnetic suspension bearingless motor, the radially extending portion is a magnetic conductive material, and the upper radially extending portion of the upper rotor and the lower radially extending portion of the lower rotor are arranged with a vertical offset.

[0016] Optionally, a positioning slot hole for connecting the axial arm of the first magnetic yoke is provided on the second magnetic yoke, and the second magnetic yoke is fixedly connected to the first magnetic yoke through the positioning slot hole.

[0017] Optionally, the outer peripheral side wall / inner peripheral side wall of the second magnetic yoke is fixedly connected to a part of the inner side wall / outer side wall of the axial arm of the first magnetic yoke.

[0018] Optionally, 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 of the rotor, and the controller is used to regulate the current direction and magnitude of the drive coil group.

[0019] The present invention has the following beneficial effects: 1. The structure of the above-mentioned composite rotor is simple. Through the cooperation of the connecting magnet and the radially extending portion, the magnetic field strength is increased, the magnetic circuit is optimized, the torque and axial stiffness of the rotor are improved, and it has better working performance; and there are various deformation schemes for this rotor. Through the ingenious setting of 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.

[0020] 2. The stator structure of the composite magnetic suspension bearingless motor is simple and compact, uses fewer coils, has good magnetic flux collection effect, and can greatly reduce the manufacturing cost and maintenance cost of the motor stator.

[0021] 3. Through the mutual cooperation of the above-mentioned composite rotor and stator, not only the manufacturing cost of the motor is effectively reduced, the motor can be flattened as a whole, the space utilization rate of the motor is improved, and the overall structure of the motor is more compact and the volume is more miniaturized, but also the magnetic field utilization rate and the working efficiency of the rotor are effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an exploded schematic view of the structure of a magnetic suspension bearingless motor stator in the prior art; Figure 2 is a three-dimensional structure schematic view of the magnetic suspension bearingless motor in Embodiment 1; Figure 3Stereogram of the stator of the magnetic levitation bearingless motor for Embodiments 1 and 2; Figure 4 Side view of the stator of the magnetic levitation bearingless motor for Embodiments 1 and 2; Figure 5 Schematic longitudinal sectional structure diagram of the motor applying the stator structure of Embodiment 1; The closed-loop route with arrows in the figure represents the main magnetic circuit; Figure 6 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 of Embodiment 1; A is the top view of the upper rotor, and B is the top view of the lower rotor; The closed-loop route with arrows in the figure represents the main magnetic circuit; Figure 7 Stereogram of the rotor adopted in the motor of Embodiment 1; Figure 8 Stereogram of the magnetic levitation bearingless motor of Embodiment 2; Figure 9 Stereogram of the rotor adopted in the motor of Embodiment 2; Figure 10 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 of Embodiment 2; A is the top view of the upper rotor, and B is the top view of the lower rotor; The closed-loop route with arrows in the figure represents the main magnetic circuit; Figure 11 Schematic sectional structure diagram of the rotor adopted in the motor; A is the rotor of one implementation manner, and B is the rotor of another implementation manner. Specific implementation manners

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection 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", "up", "down", "inside", "outside", "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 understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present 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 used 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.

[0025] Embodiment 1 As Figure 2 shown, this embodiment provides a composite magnetic levitation bearingless motor, which includes: a rotor 1 and a stator 2. The stator includes: a first yoke group and an annular second yoke 23 vertically fixed on the first yoke group. The first yoke group is composed of a plurality of longitudinally arranged first yokes 21 arranged in a circumferential pattern centered on the rotor. The second yoke is fixedly connected to all the first yokes; drive coil groups 24 for driving the rotor to levitate and rotate are wound on the portions of the second yoke located between two adjacent first yokes.

[0026] Stator structure In this embodiment, as Figures 3 - 4 shown, 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 central axis of the rotor installation position.

[0027] During operation, two closed loops are formed between the second yoke connection part where the main magnetic path coil is located, the upper / lower parts of the first yoke on the left and right sides of each drive coil group, and the corresponding radially extending parts, which are symmetrically distributed in the upper and lower radial directions. The upper and lower closed main magnetic paths share a part of the magnetic path in the second yoke.

[0028] In this embodiment, the first yoke includes an axially arranged axial arm 21a and radially extending arms 21b extending from the upper and lower ends of the axial arm to the rotor mounting position respectively. The structure of the first yoke is similar to a C-shaped structure.

[0029] Specifically, in this embodiment, the number of the first yokes is 8, and the number of the rotor magnetic poles cooperating with them 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 radially extending parts of the rotor can be 2, 4, or 8; 2 or 4.

[0030] In this embodiment, in order to facilitate the installation of the second yoke and its connection with the first yoke and ensure that magnetic lines of force can be connected between the second yoke and the adjacent first yoke, the following settings are made: a positioning slot hole (not shown in the figure) for the axial arm of the first yoke to penetrate is provided on the second yoke 23, and the second yoke and the first yoke are fixedly connected, such as by bonding, screwing, welding, or riveting and other fixed connection methods.

[0031] In other embodiments, the outer peripheral side wall / inner peripheral side wall of the second yoke is clamped and bonded with the inner side wall / outer side wall of the axial arm of the first yoke, or fixed connection is carried out in other ways.

[0032] The second yoke is composed of a plurality of second annular laminations laminated in the stacking direction, and the stacking direction is axially or radially arranged. The first yoke is formed by laminating a plurality of first laminations along the stacking direction. The laminations can be made of silicon steel sheets.

[0033] In this embodiment, the second yoke is formed by a plurality of second annular laminations stacked up and down. The first yoke is formed by stacking a plurality of C-shaped first laminations back and forth.

[0034] In other embodiments, the second yoke is formed by laminating a plurality of annular laminations arranged concentrically inside and outside.

[0035] In this embodiment, each drive coil group includes a suspension coil for the suspension magnetic field of the rotor and a rotation coil for providing a rotation magnetic field for the rotor. 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.

[0036] In other embodiments, each driving coil group is a coil that simultaneously provides a rotating magnetic field and a levitation magnetic field for the rotor. At this time, a single coil provides both the rotating magnetic field and the levitation magnetic field for the permanent magnet rotor. The structure with only one coil is simpler, but it has higher requirements for the control system.

[0037] Rotor structure As Figure 7 shown, the rotor includes a non-magnetic connecting shaft 12 arranged longitudinally and upper rotor 11 and lower rotor 13 vertically arranged at both ends of the connecting shaft. On the outer sides of the upper rotor and the lower rotor, a plurality of radially extending parts (i.e., radially extending parts) evenly distributed circumferentially are symmetrically arranged radially outward. The main bodies of the upper rotor and the lower rotor are made of magnetic conductive materials. Between adjacent radially extending parts, radially magnetized connecting magnets 15 are embedded, and the polarities of the connecting magnets in the same horizontal plane are the same.

[0038] In this embodiment, the rotor is a composite rotor. The circular main bodies of the upper rotor and the lower rotor are made of soft magnetic materials. On the outer sides of the main bodies of the upper rotor and the lower rotor, a plurality of radially extending parts 111 evenly distributed circumferentially are respectively arranged along the radial arm direction at the top of the stator in the radial direction. The radially extending parts are also made of soft magnetic materials. Between adjacent radially extending parts 111, radially magnetized connecting magnets 15 are embedded. 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 above-mentioned connecting magnets (permanent magnets) embedded in adjacent radially extending parts of the rotor can provide an additional excitation magnetic field to enhance the torque of the motor; in addition, the connecting magnet can provide a basic magnetic field, making the rotor have a polarity and can attract magnetic conductive materials. Coupled with the principle of minimum magnetic resistance, the axial stiffness is 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 part of the upper rotor and the lower radially extending part of the lower rotor overlap up and down.

[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 is arranged in cooperation with the annular second magnetic yoke of the stator in this way, the main magnetic circuit can be further optimized.

[0042] In this embodiment, the radially extending part is a fan-shaped tooth 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 part of the rotor are complementary in shape, and the overall forms a disk-shaped upper rotor or lower rotor. In other embodiments, the shapes of the radially extending part and the connecting magnet can also have other deformations, not limited to the drawings of this embodiment.

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

[0044] The connecting shaft is made of non-magnetic materials, such as plastics, aluminum alloys, copper alloys, stainless steels, 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 member.

[0045] In this embodiment, the number of radially extending portions on each rotor is 4, and the number of connecting magnets is also 4, with consistent specifications. The specifications of the radially extending portions and the connecting magnets are kept consistent. In other embodiments, the number of radially extending portions and connecting magnets on the upper and lower rotors can be reasonably adjusted, not limited to this embodiment.

[0046] In this embodiment, the radially extending portion and the upper rotor / lower rotor body are integrally designed, or the radially extending portion and the upper rotor / lower rotor body are fixedly connected by various existing methods.

[0047] Principle of rotor rotation: As Figure 6 shown, at a certain moment, the rotating coils on the two second magnetic yokes 23 that are radially symmetric and not aligned with the radially extending portions of the rotor are simultaneously energized. The magnetic force lines excited thereby flow counterclockwise to the left (or clockwise to the right), respectively, upward along the upper part of the axial arm of the first magnetic yoke and then upward to the upper radial arm, and at the same time downward along the lower part of the axial arm of the first magnetic yoke and then downward to the lower radial arm. Then, they pass through the corresponding upper / lower radially extending portions of each radial arm and flow horizontally to the adjacent connecting magnet, and then return to the second magnetic yoke through the corresponding another first magnetic yoke, thereby forming two upper closed magnetic circuits distributed on the left and right, and at the same time forming a lower closed main magnetic circuit symmetric to the upper closed magnetic circuit. Since the path of this magnetic circuit at the air gap is not the shortest distance, based on the principle of the shortest magnetic circuit, the rotor will rotate clockwise until the radial arm of the first magnetic yoke is aligned with the radially extending portion, so that the magnetic force lines can be closed through the shortest distance. At this time, the rotating coils on another pair of first magnetic yokes that form a certain angle with this pair of first magnetic yokes work in the same way as above, and pull the rotor to continue rotating clockwise. According to the above rules, the rotating coils at the corresponding positions in the stator are energized in turn, thereby realizing the continuous rotation of the rotor.

[0048] In other cases, the rotation drive can also be controlled by using two pairs of cross-shaped C-shaped magnetic yokes according to the above rules to enhance the rotation driving force.

[0049] Since the second magnetic ring where the upper and lower closed magnetic circuits share the coil is used, the directions of the symmetrically distributed upper and lower magnetic circuits are the same. During operation, by controlling the drive coil group located in the second magnetic ring part, the upper and lower two sets of main magnetic circuits arranged symmetrically can be controlled simultaneously, so as to realize the synchronous regulation of the upper and lower parts of the rotor.

[0050] The suspension principle of the rotor: As Figure 5 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 the second yoke of the stator are energized and the current magnitude is adjusted so that the axial tension received by the rotor is equal, the rotor can achieve radial centering suspension. Thus, it can be seen that the axial suspension of the rotor in this embodiment is realized by relying on the magnetic resistance principle of the shortest magnetic flux path closure. When the rotor has a radial offset, the suspension coil on the side where the air gap of the stator increases will increase the current, so that the attraction force on this side increases to correct the radial offset of the rotor.

[0051] In this embodiment, a connecting magnet is embedded between the radial extension parts of the original reluctance rotor. The connecting magnet provides an additional magnetic field for the rotor, enabling the superposition of magnetic fields under the electromagnetic field of the original stator coil. This not only significantly improves the magnetic field intensity, but also makes the improved main magnetic circuit shorter and the magnetic resistance smaller, and the torque and axial stiffness of the rotor are significantly improved.

[0052] On the above basis, the arrangement of the coils on the annular second yoke of the stator not only reduces the number of coils, makes the coil layout in the middle of the stator, and is convenient for the flat design and miniaturization of the stator volume; moreover, this design realizes the control of the upper and lower two symmetrically arranged short magnetic circuits on the adjacent two first yokes by the above-mentioned set of coils, which not only makes the main magnetic circuit shorter and the magnetic resistance smaller, but also ensures the magnetic field intensity and torque. In addition, since the annular second yoke connects the magnetic circuits between the adjacent independent first yokes, the leakage magnetic flux of the first yoke is effectively reduced, and the magnetic field utilization rate is improved.

[0053] In this embodiment, the stator further includes a housing, and the above-mentioned first yoke and second yoke are arranged inside the housing and fixedly connected to the housing.

[0054] The stator 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 of the rotor, and the controller is used to regulate the current direction and magnitude of the drive coil group.

[0055] For other structures (such as sensors, etc.) arranged inside the stator, refer to the prior art and are omitted here.

[0056] Embodiment 2 As Figure 8As shown, this embodiment provides a composite magnetic levitation bearingless motor, which includes the stator described in Embodiment 1 and another rotor.

[0057] In this embodiment, the difference between the rotor and the rotor in Embodiment 1 is that: As Figure 9 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.

[0058] 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.

[0059] Figure 10 shows the magnetic induction line distribution in the upper rotor and the lower rotor; the magnetic induction line distribution in the longitudinal section of this motor is as shown in Figure 5 Embodiment 1. 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.

[0060] Compared with the motor in 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 at corresponding positions on the upper and lower rotors are the same. This setting not only greatly improves the magnetic field strength of the rotor, increases the magnetic field density per unit area, and makes the main magnetic circuit shorter, but also can significantly improve the torque and axial stiffness of the rotor; and because there are two independently controllable closed-loop main magnetic circuits symmetrically distributed up and down in the stator and the rotor, independent control of the rotation and suspension torques of the upper and lower parts of the rotor can be achieved, improving the stability and torque of the rotor.

[0061] Embodiment 3 This embodiment provides a composite magnetic levitation bearingless motor, which includes the stator described in Embodiment 1 and another rotor.

[0062] In this embodiment, on the basis of Embodiment 1 or Embodiment 2, the rotor is set differently as follows: the upper radially extending portion 111 of the upper rotor and the lower radially extending portion 111 of the lower rotor are symmetric up and down and are arranged in a staggered manner.

[0063] Preferably, the misalignment angle between the upper radial extension portion 111 of the upper rotor and the corresponding lower radial extension portion 111 of the lower rotor is 45°. The main magnetic circuit distribution of this solution is equivalent to that of the main magnetic circuit with the upper and lower rotors overlapping, and both form a magnetic circuit closed loop along the path with the minimum magnetic resistance. This way of setting the upper and lower rotors out of alignment can make the transition of the rotor smoother during rotation and the torque ripple smaller.

[0064] For other settings of the motor in this embodiment, refer to Embodiment 1, and its working principle also refers to Embodiment 1.

[0065] 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 substitutions 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 substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A composite magnetic suspension bearingless motor, characterized in that: include: A rotor (1) and a stator (2), the stator comprising: a first yoke group and an annular second yoke (23) vertically fixed to the first yoke group, the first yoke group comprising a plurality of first yokes (21) arranged longitudinally and circumferentially with the rotor as the center, the second yoke being fixedly connected to all the first yokes; a driving coil group (24) for driving the rotor to suspend and rotate is wound around a portion of the second yoke located between two adjacent first yokes; The rotor comprises a non-magnetic connecting shaft (12) arranged longitudinally, 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 magnetic conductive material. Radially magnetized connecting magnets (15) are embedded between adjacent radial extensions. The polarities of the connecting magnets on the same horizontal plane are consistent.

2. The composite magnetic suspension bearingless 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.

3. The composite magnetic suspension bearingless motor according to claim 1, characterized in that: Radial arms (21b) extend from the upper and lower ends of the axial arm of the first magnetic yoke respectively.

4. The composite magnetic suspension bearingless motor according to claim 3, characterized in that: Each driving coil group includes a suspension coil for the rotor suspension magnetic field and a rotating coil for providing a rotating magnetic field for the rotor; or each driving coil group is a coil that provides both a rotating magnetic field and a suspension magnetic field for the rotor.

5. The composite magnetic suspension bearingless motor according to claim 1, characterized in that: The second magnetic yoke comprises a plurality of second annular laminations which are stacked one on another along a stacking direction, and the stacking direction is axial or radial.

6. The composite magnetic suspension bearingless motor according to claim 3, 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 arranged in overlapping projections or vertically staggered, and the magnetization directions of the corresponding connecting magnets (15) on the upper rotor and the lower rotor are opposite.

7. The composite magnetic suspension bearingless motor according to claim 3, 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 symmetrical in upper and lower directions and are arranged in an overlapping / offset manner, and the magnetizing directions of the connecting magnets (15) at corresponding positions on the upper rotor and the lower rotor are the same.

8. The composite magnetic suspension bearingless motor according to claim 3, 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 magnets 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 top and bottom and are arranged with overlapping / offset projections, and the magnetization directions of the connecting magnets (15) at corresponding positions on the upper rotor and the lower rotor are opposite.

9. The composite magnetic suspension bearingless motor according to claim 3, characterized in that: The radial extension portion is a radially magnetized magnet, the magnetization directions of the radial extension portion and the adjacent connecting magnets 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 overlap / misaligned in projection, and the magnetization directions of the connecting magnets (15) at corresponding positions on the upper rotor and the lower rotor are consistent.

10. The composite magnetic suspension bearingless motor according to claim 3, 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 driving coil group.

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