Five-degree-of-freedom magnetic suspension motor structure and integrated design method thereof

Abstract

The invention provides a five-degree-of-freedom magnetic suspension motor structure and an integrated design method thereof, and relates to the technical field of magnetic suspension motors, and the five-degree-of-freedom magnetic suspension motor structure is composed of a rotating shaft, a protection bearing, a displacement sensor, a bearingless permanent magnet motor, a housing, an axial-radial integrated magnetic bearing, a rotary transformer and other parts. According to the motor structure, an integrated structure of a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing is adopted, five-degree-of-freedom suspension of the motor is realized, the number of magnetic bearing parts is reduced, the size of the motor is reduced, the power density of the motor can be remarkably improved, and the motor structure has wide application prospects in the fields of high-speed rotating mechanical equipment and the like. The integrated design method comprises a design method of the bearingless permanent magnet motor, a design method of the axial-radial integrated magnetic bearing and a design checking method, and through series-parallel connection mixed collaborative design of different parts and an accurate magnetic circuit calculation method, the motor design time is shortened, and the design efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic levitation motors, and in particular to a five-degree-of-freedom magnetic levitation motor structure and an integrated design method thereof. Background Art

[0002] Magnetic levitation technology enables high motor speeds, high power density, and low vibration and noise. A five-degree-of-freedom magnetic levitation motor refers to a motor system capable of active levitation control in five degrees of freedom. These five degrees of freedom include four radial degrees of freedom and one axial degree of freedom. Its advantages include: Frictionlessness: Since there is no mechanical contact between the rotor and stator, friction and wear are eliminated, improving system efficiency and lifespan. High precision: High-precision position and attitude control is achieved, making it suitable for applications requiring high-precision rotation. Low energy consumption: Compared to traditional mechanical bearings, magnetic bearings reduce energy loss, improving overall system efficiency. Long life: Due to reduced mechanical wear, the system's service life is significantly extended. Currently, five-degree-of-freedom magnetic levitation motors have been widely used in various technical fields, including aerospace, high-end equipment manufacturing, energy and power generation, and other key sectors. Existing technologies primarily use two radial magnetic bearings and one axial magnetic bearing to achieve five-degree-of-freedom levitation of the motor. However, the large size of the magnetic bearings hinders the improvement of critical speed and power density. Currently, bearingless motor technology, as an emerging technology, can place two sets of windings in one motor to provide torque and suspension force at the same time, but it can only provide two degrees of freedom suspension.

[0003] The invention patent with publication number CN115733323A provides a five-degree-of-freedom, ultra-high-speed, bearingless permanent magnet motor. The two ends of a cylindrical solid permanent magnet are connected to a rotating shaft. A housing is mounted on the outside of the cylindrical solid permanent magnet. A stator core is fixedly mounted on the housing. A set of torque windings is embedded in the bottom layer of the stator core, and two sets of suspension windings are embedded in the upper layer of the stator core. End caps are fixedly mounted on both sides of the housing. Auxiliary bearings are installed between the end caps and the rotating shaft. Passive permanent magnet bearings are embedded in both the end caps and the rotating shaft. However, its topological design of "two bearingless motors + one passive axial magnetic bearing" has technical drawbacks such as a large number of motors, a lack of active axial control, and a low level of integration.

[0004] Patent publication number CN111211709A discloses a thrust-disk-free five-degree-of-freedom (DOF) magnetic levitation motor. The motor comprises a rotating shaft, a two-DOF radial suspension assembly that generates radial levitation force and has a rotor core coaxially mounted with the rotating shaft, a one-DOF axial suspension assembly that generates axial levitation force and has a rotor core coaxially mounted with the rotating shaft, a two-DOF radial suspension bearingless motor assembly that generates radial levitation force and can drive the rotating shaft, and an external stator yoke that surrounds and supports the two-DOF radial suspension assembly, the one-DOF axial suspension assembly, and the two-DOF radial suspension bearingless motor assembly. The annular permanent magnets of the two-DOF radial suspension assembly and the one-DOF axial suspension assembly are radially magnetized in opposite directions, forming a permanent magnetic bias field. However, the motor's five-DOF levitation is achieved using a "bearingless motor + one radial magnetic bearing + one axial magnetic bearing" topology. However, the diverse and differentiated suspension support methods significantly increase the design and integration complexity of the magnetic levitation motor, hindering the application of magnetic levitation technology in high-speed rotating machinery. The motor structure also has technical defects such as the use of many magnetic bearing components, complex processes and low integration.

[0005] In view of this, it is necessary to study a five-degree-of-freedom magnetic levitation motor structure and its integrated design method to solve the above technical problems. Summary of the Invention

[0006] In view of the technical problems that the magnetic bearings in the background technology are large in size, which is not conducive to improving the critical speed and power density, and the diversity and differentiation of suspension support methods will significantly increase the design and integration difficulty of magnetic levitation motors, which is not conducive to the application of magnetic levitation technology in high-speed rotating mechanical equipment, the present invention provides a five-degree-of-freedom magnetic levitation motor structure and its integrated design method. Starting from the topological structure and design method, the power density and design efficiency of the magnetic levitation motor are further improved, which is of great significance to the promotion and application of magnetic levitation technology.

[0007] In a first aspect, an embodiment of the present invention provides a five-degree-of-freedom magnetic levitation motor structure, including a rotating shaft, further comprising: A bearingless permanent magnet motor generates a suspension force with two radial degrees of freedom and can drive the rotating shaft to rotate; The axial-radial integrated magnetic bearing has the functions of both radial and axial magnetic bearings, generating a suspension force with two radial degrees of freedom and one axial degree of freedom, a total of three degrees of freedom; The bearingless permanent magnet motor and the axial-radial integrated magnetic bearing are respectively mounted around the outer periphery of both sides of the rotating shaft and are coaxially assembled with the rotating shaft; The bearingless permanent magnet motor and the axial-radial integrated magnetic bearing cooperate with each other to jointly realize five-degree-of-freedom magnetic suspension.

[0008] As a further improvement of the present invention, the axial-radial integrated magnetic bearing includes a left axial magnetic bearing stator core, a right axial magnetic bearing stator core, a radial magnetic bearing stator core, and a magnetic bearing rotor; the magnetic bearing rotor is fixed on the rotating shaft and includes a magnetic bearing inner rotor and a magnetic bearing outer rotor that are interference fit with each other; After the radial magnetic bearing stator core is installed on the right axial magnetic bearing stator core by interference fit, the left axial magnetic bearing stator core and the right axial magnetic bearing stator core are fixedly assembled.

[0009] As a further improvement of the present invention, the radial magnetic bearing stator core, the left axial magnetic bearing stator core, and the right axial magnetic bearing stator core share a magnetic bearing rotor.

[0010] As a further improvement of the present invention, the axial-radial integrated magnetic bearing also includes an axial magnetic bearing stator winding and a radial magnetic bearing stator winding; the axial magnetic bearing stator winding and the radial magnetic bearing stator winding are arranged alternately in the radial direction and are respectively arranged into two layers, upper and lower.

[0011] As a further improvement of the present invention, the bearingless permanent magnet motor includes a motor stator core, a permanent magnet, a motor rotor, a torque winding and a suspension winding; the torque winding and the suspension winding are respectively embedded in the upper and lower layers (or the lower and upper layers) of the motor slot of the motor stator core; the difference in the number of pole pairs between the torque winding and the suspension winding is 1.

[0012] As a further improvement of the present invention, the five-degree-of-freedom magnetic levitation motor structure also includes displacement sensors arranged at both ends and axial positions of the motor, a rotary transformer arranged at the non-extended end position of the motor, protective bearings respectively arranged on both sides of the motor, and a casing.

[0013] As a further improvement of the present invention, the radial magnetic bearing stator core adopts one of 8-pole, 12-pole, and 16-pole types, and uses high-magnetic-permeability, low-loss silicon steel sheet material or high-magnetic-permeability solid steel material; the left axial magnetic bearing stator core and the right axial magnetic bearing stator core adopt a U-shaped structure or an E-shaped structure, and use high-magnetic-permeability solid steel material; the magnetic bearing rotor adopts high-magnetic-permeability, low-loss silicon steel sheet or high-magnetic-permeability solid steel material.

[0014] In a second aspect, an embodiment of the present invention further provides an integrated design method for the above-mentioned five-degree-of-freedom magnetic levitation motor structure, comprising three steps: a design method for a bearingless permanent magnet motor, a design method for an axial-radial integrated magnetic bearing, and a design verification method; The specific steps of the design method of the bearingless permanent magnet motor are as follows: S1. Main dimension calculation: including main dimension calculation of bearingless permanent magnet motor and air gap length calculation; The main dimensions of bearingless permanent magnet motors are determined by input power: ; in: D i1 is the inner diameter of the stator; L ef is the effective length of the core; n is the rated speed; p 1 is the input power of the motor; α p is the calculated pole arc coefficient of the motor; K nm is the waveform coefficient of the air gap magnetic field; K dp is the fundamental wave winding coefficient of the motor; A is the torque winding electrical load; B δ is the magnetic flux amplitude generated by the permanent magnet at the air gap; The motor air gap length is determined based on the main dimensions of the bearingless permanent magnet motor: ; in: δ is the motor air gap length; S2. Permanent magnet calculation: Calculate the thickness of the permanent magnet based on the air gap length and working magnetic flux density: ; in: μ 0 is the vacuum permeability; H c is the coercive force of the permanent magnet; B 0 is the working magnetic flux density; S3. Winding parameter calculation: Calculate the number of phase series conductors of the torque winding based on the motor magnetic flux: , ; in: U ph is the phase voltage; Φ is the motor flux; f is the operating frequency; PM is the number of torque winding pole pairs; Combined with the motor support load requirements, the number of phase series conductors of the suspension winding is further calculated: , ; in: P B is the number of pole pairs of the suspension winding; L B is the self-inductance of the suspension force winding; N M 、 N B are the equivalent turns of each phase winding in series of the torque winding and the suspension force winding respectively; is the flux linkage of each phase of the torque winding; F To support the load; i B is the maximum suspension current; r are the outer diameters of the motor rotor core respectively; S4. Stator parameter calculation: determined based on slot fill rate and wire diameter, including slot shape selection and stator size calculation.

[0015] As a further improvement of the present invention, after obtaining a design scheme of a bearingless permanent magnet motor by the design method of the bearingless permanent magnet motor, the rotor weight and shaft diameter parameters of the bearingless permanent magnet motor are used as input quantities of the design method of the axial-radial integrated magnetic bearing; The design method of the axial-radial integrated magnetic bearing comprises the following steps: P1. Coupled Magnetic Circuit Modeling: Considering the magnetic circuit coupling relationship between axial and radial magnetic bearings, the distributed magnetic circuit method is used to divide the air gap circumference of the magnetic bearing into blocks and multiple nodes to form multiple magnetic circuits. The magnetomotive force equation of the axial-radial integrated magnetic bearing is written based on the magnetic circuits. The air gap magnetic flux density is then iteratively calculated to establish a mapping relationship between magnetic bearing parameters and performance. P2. Calculation of magnetic bearing winding parameters: Calculate the number of turns of the magnetic bearing based on the air gap length and bias magnetic density and electrical density: ; in: N c is the number of turns of the magnetic bearing; B b is the bias flux density of the magnetic bearing; g0 is the air gap length of the magnetic bearing; I b is the bias current of the magnetic bearing; P3. Calculation of magnetic bearing rotor size parameters: Calculate the rotor inner and outer diameters and length parameters based on the maximum allowable linear speed and magnetic pole width; P4. Calculation of magnetic bearing stator size parameters: Calculate the stator slot size parameters based on the number of turns, wire diameter and slot fill rate.

[0016] As a further improvement of the present invention, the design method of the bearingless permanent magnet motor and the design method of the axial-radial integrated magnetic bearing adopt parallel synchronous design. After the two are completed, the design schemes obtained by the design method of the bearingless permanent magnet motor and the design method of the axial-radial integrated magnetic bearing are input into the calculation parameters of the design verification method through serial design.

[0017] The design verification method includes electromagnetic, temperature field, dynamic, and strength calculations. The electromagnetic, temperature, dynamic, and strength performance of the five-degree-of-freedom magnetic levitation motor are calculated separately and then iterated until the requirements are met, based on performance requirements. The electromagnetic and temperature field calculations are performed serially, while these calculations are performed in parallel with the dynamic and strength calculations.

[0018] The working principle of the five-degree-of-freedom magnetic levitation motor structure provided by the present invention is: The five-degree-of-freedom (DOF) magnetic levitation motor structure is primarily integrated with a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing. The bearingless permanent magnet motor incorporates a suspension winding in addition to the traditional torque winding, generating two radial degrees of freedom (DOF) of levitation force through magnetic field modulation. The axial-radial integrated magnetic bearing utilizes a shared rotor and a cross-wound winding arrangement, combining the functions of both axial and radial magnetic bearings to provide levitation force with two radial degrees of freedom and one axial degree of freedom for the magnetic levitation motor structure. The bearingless permanent magnet motor and axial-radial integrated magnetic bearing work together to achieve five-DOF magnetic levitation. Furthermore, a displacement sensor measures displacement signals for levitation control of the magnetic levitation motor; a rotary transformer measures speed signals for rotation control; and a protective bearing protects the rotor of the magnetic levitation motor from direct contact with the stator in the event of a fall. Thus, the synergistic interaction of these components creates the integrated structure of a five-DOF magnetic levitation motor. The five-degree-of-freedom magnetic levitation motor structure adopts a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing. Compared with the five-degree-of-freedom magnetic levitation motor in the existing technology, it reduces the number of suspension components and improves space utilization. It has the technical advantages of active five-degree-of-freedom control, small size and high integration.

[0019] Beneficial effects: The five-degree-of-freedom magnetic levitation motor structure provided by this invention utilizes a bearingless permanent magnet motor and an integrated axial-radial magnetic bearing. While achieving five-degree-of-freedom levitation, this design, through a shared rotor and staggered winding arrangement, reduces the number of magnetic bearing components and significantly reduces the motor's size. Compared to traditional magnetic levitation motors, this design boasts a high level of structural integration and a highly efficient design approach, significantly improving the motor's power density and design efficiency. It has broad application prospects in high-speed rotating machinery and other fields.

[0020] 2. The five-degree-of-freedom magnetic levitation motor structure provided by the present invention adopts a shared rotor and staggered winding arrangement process for the axial-radial integrated magnetic bearing, which shortens the axial length of the motor and improves the system integration; and through the inner and outer rotor structures of the magnetic bearing, the rotor eddy current loss at high speed can be reduced, thereby improving the working efficiency of the motor.

[0021] 3. The integrated design method of the five-degree-of-freedom magnetic levitation motor structure provided by the present invention adopts the distributed magnetic circuit method to model the axial and radial coupled magnetic circuits of the axial-radial integrated magnetic bearing, which is used to establish the relationship between the performance and parameters of the magnetic bearing, thereby significantly improving the design efficiency of the magnetic bearing.

[0022] 4. The integrated design method of the five-degree-of-freedom magnetic levitation motor structure provided by the present invention first designs a bearingless permanent magnet motor to obtain a design scheme of the bearingless permanent magnet motor, and then uses the rotor weight, shaft diameter and other parameters of the bearingless permanent magnet motor as input quantities of the axial-radial integrated magnetic bearing design method to design the axial-radial integrated magnetic bearing. Finally, the design scheme of the bearingless permanent magnet motor and the design scheme of the axial-radial integrated magnetic bearing obtained above are input into the design verification method to realize the collaborative design of the bearingless permanent magnet motor and the axial-radial integrated magnetic bearing under the multidisciplinary verification method, thereby improving the design efficiency of the magnetic levitation motor.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0025] Figure 1A schematic diagram of a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a bearingless permanent magnet motor in a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of an axial-radial integrated magnetic bearing in a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present invention; Figure 4 A schematic flow chart of an integrated design method for a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present invention; Reference numerals, in all drawings, the same numerals are used to represent the same components or structures, and letters represent differences in installation positions, wherein the respective numerals are represented as follows: 10. Five-degree-of-freedom magnetic levitation motor structure; 11. Rotating shaft; 12. Protective bearing; 13. Displacement sensor; 14. Bearingless permanent magnet motor; 15. Housing; 16. Axial-radial integrated magnetic bearing; 17. Rotary transformer; 141. Motor stator core; 142. Torque winding; 143. Suspension winding; 144. Permanent magnet; 145. Motor rotor; 161. Left axial magnetic bearing stator core; 162. Radial magnetic bearing stator core; 163. Axial magnetic bearing stator winding; 164. Radial magnetic bearing stator winding; 165. Magnetic bearing rotor; 166. Right axial magnetic bearing stator core; 1651. Magnetic bearing inner rotor; 1652. Magnetic bearing outer rotor; 20. Integrated design method for five-degree-of-freedom magnetic levitation motor structure; 21. Design method for bearingless permanent magnet motor; 22. Design method for axial-radial integrated magnetic bearing; 23. Design verification method (multidisciplinary verification method). DETAILED DESCRIPTION

[0026] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions.

[0028] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present invention, "plurality" means more than two, unless otherwise specifically defined.

[0029] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] In the description of the embodiments of the present invention, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exists simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0031] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0032] In the description of the embodiments of the present invention, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention.

[0033] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0034] In order to solve the technical problem in the prior art that the magnetic bearings are large in size and are not conducive to improving the critical speed and power density, the present invention provides a five-degree-of-freedom magnetic levitation motor structure and an integrated design method thereof. Starting from the topological structure and design method, a structure of a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing is adopted. While realizing the five-degree-of-freedom suspension of the motor, the power density and design efficiency of the magnetic levitation motor are further improved through design methods such as a shared rotor and a cross-winding arrangement, which is of great significance for the promotion and application of magnetic levitation technology.

[0035] Example 1 Please refer to Figures 1 to 3 As shown, embodiment 1 of the present invention provides a five-degree-of-freedom magnetic levitation motor structure 10, which is mainly composed of a rotating shaft 11, a protective bearing 12, a displacement sensor 13, a bearingless permanent magnet motor 14, a housing 15, an axial-radial integrated magnetic bearing 16, a rotary transformer 17 and other component structures.

[0036] The bearingless permanent magnet motor 14 generates a suspension force with two radial degrees of freedom and can drive the rotating shaft 11 to rotate. The axial-radial integrated magnetic bearing 16 has the functions of both radial and axial magnetic bearings, generating a suspension force with two radial degrees of freedom and one axial degree of freedom, a total of three degrees of freedom; The bearingless permanent magnet motor 14 and the axial-radial integrated magnetic bearing 16 are respectively installed around the outer periphery of both sides of the rotating shaft 11 and are coaxially assembled with the rotating shaft 11; the bearingless permanent magnet motor 14 and the axial-radial integrated magnetic bearing 16 cooperate with each other to jointly realize five-degree-of-freedom magnetic suspension.

[0037] See also Figure 1 and Figure 3 As shown, the bearingless permanent magnet motor 14 mainly includes a stator core 141, a torque winding 142, a suspension winding 143, permanent magnets 144, and a rotor 145. The torque winding 142 and suspension winding 143 are embedded in the upper and lower layers of the motor slots, respectively.

[0038] The difference in pole pairs between the torque winding 142 and the suspension winding 143 is 1. The magnetic field generated by the suspension winding 143 modulates the motor's existing balanced magnetic field, applying radial force to the motor rotor 145 and achieving self-levitation. Thus, the bearingless permanent magnet motor 14 provides two radial degrees of freedom of levitation for the five-degree-of-freedom magnetic suspension motor structure 10.

[0039] See also Figure 1 and Figure 2As shown, the axial-radial integrated magnetic bearing 16 mainly includes a left axial magnetic bearing stator core 161, a radial magnetic bearing stator core 162, an axial magnetic bearing stator winding 163 and a radial magnetic bearing stator winding 164, a magnetic bearing rotor 165, a right axial magnetic bearing stator core 166 and other component structures.

[0040] The axial magnetic bearing stator winding 163 and the radial magnetic bearing stator winding 164 are arranged alternately in the radial direction, with upper and lower layers respectively.

[0041] In some specific embodiments, the magnetic bearing rotor 165 is fixed to the rotating shaft 11 by shrink fitting, and the radial magnetic bearing stator core 162 is shrink fitted onto the right axial magnetic bearing stator core 166 by interference fit, and then the left axial magnetic bearing stator core 161 and the right axial magnetic bearing stator core 166 are assembled by bolts.

[0042] In the axial-radial integrated magnetic bearing 16, the radial magnetic bearing stator core 162 shares a magnetic bearing rotor 165 with the left axial magnetic bearing stator core 161 and the right axial magnetic bearing stator core 166, so that it has the functions of both radial magnetic bearing and axial magnetic bearing, providing three degrees of freedom of suspension force, two radial degrees of freedom and one axial degree of freedom, for the five-degree-of-freedom magnetic levitation motor structure 10.

[0043] The magnetic bearing rotor 165 is fixed on the rotating shaft 11 and includes a magnetic bearing inner rotor 1651 and a magnetic bearing outer rotor 1652 that are interference fit with each other.

[0044] In some embodiments, the radial magnetic bearing stator core 162 adopts one of the 8-pole, 12-pole, and 16-pole types, and adopts high-magnetic-permeability, low-loss silicon steel sheet materials; the left axial magnetic bearing stator core 161 and the right axial magnetic bearing stator core 166 adopt a U-shaped structure or an E-shaped structure, and adopt high-magnetic-permeability solid steel materials; the magnetic bearing rotor 165 adopts high-magnetic-permeability, low-loss silicon steel sheets or high-magnetic-permeability solid steel materials.

[0045] See also Figure 1 As shown, the displacement sensors 13 are respectively arranged at both ends and the axial position of the motor to measure the displacement of the rotating shaft 11 in different directions for suspension control of the five-degree-of-freedom magnetic suspension motor structure 10.

[0046] The rotary transformer 17 is arranged at the non-extended end position of the motor to measure the rotation speed of the motor and is used for rotation control of the five-degree-of-freedom magnetic levitation motor structure 10.

[0047] The protective bearings 12 are respectively provided on both sides of the motor to protect the rotor when it falls.

[0048] The integrated five-DOF magnetic levitation motor structure 10 provided in Example 1 has an overall volume at least 20% smaller than that of a conventional magnetic levitation motor, resulting in a very high level of integration. Compared to conventional magnetic levitation motors, this motor features fewer suspended components and higher space utilization, indicating higher integration and power density, resulting in improved performance. Power density is inversely proportional to volume and speed.

[0049] Example 2 See also Figure 4 As shown, embodiment 2 of the present invention provides an integrated design method 20 for the above-mentioned five-degree-of-freedom magnetic levitation motor structure, which mainly includes three design steps: a design method 21 for a bearingless permanent magnet motor, a design method 22 for an axial-radial integrated magnetic bearing, and a design verification method (multidisciplinary verification method) 23.

[0050] Among them, the specific design process of the design method 21 of the bearingless permanent magnet motor in design step 1 is as follows: S1. Calculation of main dimensions: including calculation of main dimensions of bearingless permanent magnet motor 14 and calculation of air gap length. The main dimensions of bearingless permanent magnet motor 14 are determined according to input power: ; in: D i1 is the inner diameter of the stator; L ef is the effective length of the core; n is the rated speed; p 1 is the input power of the motor; α p is the calculated pole arc coefficient of the motor; K nm is the waveform coefficient of the air gap magnetic field; K dp is the fundamental wave winding coefficient of the motor; A is the electrical load of the torque winding 142; B δ is the magnetic flux density amplitude generated by the permanent magnet 144 at the air gap; The motor air gap length is determined based on the main dimensions of the bearingless permanent magnet motor 14: ; in: δ is the motor air gap length; S2. Calculation of permanent magnet 144: Calculate the thickness of permanent magnet 144 based on the air gap length and working magnetic flux density: ; in: μ 0 is the vacuum permeability; H c is the coercive force of the permanent magnet 144; B 0 is the working magnetic flux density; S3. Winding parameter calculation: Calculate the number of phase series conductors of the torque winding 142 based on the motor magnetic flux: , ; in: U ph is the phase voltage; Φ is the motor flux; f is the operating frequency; P M The number of pole pairs of the torque winding is 142; Combined with the motor support load requirements, the number of phase series conductors of the suspension winding 143 is further calculated: , ; in: P B The number of pole pairs for the suspension winding is 143; L B is the self-inductance of the suspension winding 143; N M 、 N B are the equivalent turns of each phase winding of the torque winding 142 and the suspension winding 143 connected in series; is the flux linkage of each phase of the torque winding 142; F To support the load; i B is the maximum suspension current; r are the outer diameters of the motor rotor core respectively; S4. Stator parameter calculation: determined based on slot fill rate and wire diameter, including slot shape selection and stator size calculation.

[0051] Design step 2: After obtaining the design scheme of the bearingless permanent magnet motor 14 through the design method 21 of the bearingless permanent magnet motor, the rotor weight and shaft diameter parameters of the bearingless permanent magnet motor 14 are used as input quantities of the design method 22 of the axial-radial integrated magnetic bearing; the design method 22 of the axial-radial integrated magnetic bearing includes the following design process: P1. Coupled Magnetic Circuit Modeling: Considering the magnetic circuit coupling relationship between axial and radial magnetic bearings, the distributed magnetic circuit method is used to divide the air gap circumference of the magnetic bearing into blocks and multiple nodes to form multiple magnetic circuits. The magnetomotive force equation of the axial-radial integrated magnetic bearing is written based on the magnetic circuits. The air gap magnetic flux density is then iteratively calculated to establish a mapping relationship between magnetic bearing parameters and performance. P2. Calculation of magnetic bearing winding parameters: Calculate the number of turns of the magnetic bearing based on the air gap length and bias magnetic density and electrical density: ; in: N c is the number of turns of the magnetic bearing; B b is the bias flux density of the magnetic bearing; g 0 is the air gap length of the magnetic bearing; I b is the bias current of the magnetic bearing; P3. Calculation of magnetic bearing rotor size parameters: Calculate the rotor inner and outer diameters and length parameters based on the maximum allowable linear speed and magnetic pole width; P4. Calculation of magnetic bearing stator size parameters: Calculate the stator slot size parameters based on the number of turns, wire diameter and slot fill rate.

[0052] Design step 3, inputting the design solutions obtained by the design method 21 of the bearingless permanent magnet motor and the design method 22 of the axial-radial integrated magnetic bearing into the calculation parameters of the design verification method 23; The design verification method 23 includes four verification processes: electromagnetic calculation, temperature field calculation, dynamic calculation, and strength calculation. It is used to calculate the electromagnetic, temperature, dynamic, and strength performance of the five-degree-of-freedom magnetic levitation motor respectively, and judge according to the performance requirements until it is iterated to meet the requirements to ensure the feasibility of the solution.

[0053] In some specific embodiments, the bearingless permanent magnet motor design method 21, the axial-radial integrated magnetic bearing design method 22, and the design verification method 23 can quickly produce a magnetic levitation motor solution that simultaneously meets multiple performance requirements, including electromagnetic, temperature, dynamics, and strength. The main design parameters of Example 2 are shown in Tables 1 and 2 below: Table 1 Main design parameters of bearingless permanent magnet motor 14 Table 2 Main design parameters of the axial-radial integrated magnetic bearing 16 Therefore, by summarizing the design data and solutions of the above three design steps, an integrated design of a five-degree-of-freedom magnetic levitation motor structure 10 was developed. Starting from the topological structure and design method, the power density and design efficiency of the magnetic levitation motor were further improved, which is of great significance for the promotion and application of magnetic levitation technology.

[0054] Those skilled in the art know that the specific design parameters of the five-degree-of-freedom magnetic levitation motor structure 10 designed by the integrated design method provided by the present invention are not limited to the specific parameter data in Example 2, and the specific parameters can also be designed and verified according to actual applications or special application requirements.

[0055] In summary, the present invention provides a five-degree-of-freedom magnetic levitation motor structure and an integrated design method thereof, which relates to the technical field of magnetic levitation motors. The structure is composed of a rotating shaft, a protective bearing, a displacement sensor, a bearingless permanent magnet motor, a housing, an axial-radial integrated magnetic bearing, a rotary transformer and other components. By adopting an integrated structure of a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing, the number of magnetic bearing components is reduced and the size of the motor is reduced while achieving five-degree-of-freedom suspension of the motor. The motor structure has the characteristics of high structural integration and efficient design method, which can significantly improve the power density and design efficiency of the motor and has broad application prospects in fields such as high-speed rotating mechanical equipment; it effectively overcomes the technical defects of the prior art that the magnetic bearing is large in size, which is not conducive to the improvement of critical speed and power density.

[0056] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A five-degree-of-freedom magnetic levitation motor structure, comprising a rotating shaft, characterized in that: Also includes: A bearingless permanent magnet motor generates a suspension force with two radial degrees of freedom and can drive the rotating shaft to rotate; The axial-radial integrated magnetic bearing has the functions of both radial and axial magnetic bearings, generating a suspension force with two radial degrees of freedom and one axial degree of freedom, a total of three degrees of freedom; The bearingless permanent magnet motor and the axial-radial integrated magnetic bearing are respectively mounted around the outer periphery of both sides of the rotating shaft and are coaxially assembled with the rotating shaft; The bearingless permanent magnet motor and the axial-radial integrated magnetic bearing cooperate with each other to jointly realize five-degree-of-freedom magnetic suspension.

2. The five-degree-of-freedom magnetic levitation motor structure according to claim 1, characterized in that: The axial-radial integrated magnetic bearing comprises a left axial magnetic bearing stator core, a right axial magnetic bearing stator core, a radial magnetic bearing stator core, and a magnetic bearing rotor; the magnetic bearing rotor is fixed on the rotating shaft and comprises a magnetic bearing inner rotor and a magnetic bearing outer rotor that are interference fit with each other; After the radial magnetic bearing stator core is installed on the right axial magnetic bearing stator core by interference fit, the left axial magnetic bearing stator core and the right axial magnetic bearing stator core are fixedly assembled.

3. The five-degree-of-freedom magnetic levitation motor structure according to claim 2, characterized in that: The radial magnetic bearing stator core, the left axial magnetic bearing stator core, and the right axial magnetic bearing stator core share a magnetic bearing rotor.

4. The five-degree-of-freedom magnetic levitation motor structure according to claim 2, characterized in that: The axial-radial integrated magnetic bearing further includes an axial magnetic bearing stator winding and a radial magnetic bearing stator winding; the axial magnetic bearing stator winding and the radial magnetic bearing stator winding are alternately arranged in the radial direction, and are respectively provided in two layers, upper and lower.

5. The five-degree-of-freedom magnetic levitation motor structure according to claim 1, characterized in that: The bearingless permanent magnet motor includes a motor stator core, a permanent magnet, a motor rotor, a torque winding and a suspension winding; the torque winding and the suspension winding are respectively embedded in the upper and lower layers of the motor slot of the motor stator core, or the torque winding and the suspension winding are respectively embedded in the lower and upper layers of the motor slot of the motor stator core; the difference in the number of pole pairs of the torque winding and the suspension winding is 1.

6. The five-degree-of-freedom magnetic levitation motor structure according to claim 1, characterized in that: The five-degree-of-freedom magnetic levitation motor structure also includes displacement sensors arranged at both ends and axial positions of the motor, a rotary transformer arranged at the non-extended end position of the motor, protective bearings respectively arranged on both sides of the motor, and a casing.

7. The five-degree-of-freedom magnetic levitation motor structure according to claim 2, characterized in that: The radial magnetic bearing stator core adopts one of 8-pole, 12-pole, and 16-pole types, and uses high-magnetic-permeability, low-loss silicon steel sheet material or high-magnetic-permeability solid steel material; the left axial magnetic bearing stator core and the right axial magnetic bearing stator core adopt a U-shaped structure or an E-shaped structure, and use high-magnetic-permeability solid steel material; the magnetic bearing rotor adopts high-magnetic-permeability, low-loss silicon steel sheet or high-magnetic-permeability solid steel material.

8. An integrated design method for a five-degree-of-freedom magnetic levitation motor structure according to any one of claims 1 to 7, characterized in that: It includes three steps: the design method of bearingless permanent magnet motor, the design method of axial-radial integrated magnetic bearing, and the design verification method; The specific steps of the design method of the bearingless permanent magnet motor are as follows: S1. Calculation of main dimensions: including calculation of main dimensions of bearingless permanent magnet motor and calculation of air gap length; main dimensions of bearingless permanent magnet motor are determined according to input power: ； in: D i1 is the inner diameter of the stator; L ef is the effective length of the core; n is the rated speed; p 1 is the input power of the motor; α p is the calculated pole arc coefficient of the motor; K nm is the waveform coefficient of the air gap magnetic field; K dp is the fundamental wave winding coefficient of the motor; A is the torque winding electrical load; B δ is the magnetic flux amplitude generated by the permanent magnet at the air gap; The motor air gap length is determined based on the main dimensions of the bearingless permanent magnet motor: ； in: δ is the motor air gap length; S2. Permanent magnet calculation: Calculate the thickness of the permanent magnet based on the air gap length and working magnetic flux density: ； in: μ 0 is the vacuum permeability; H c is the coercive force of the permanent magnet; B 0 is the working magnetic flux density; S3. Winding parameter calculation: Calculate the number of phase series conductors of the torque winding based on the motor magnetic flux: ， ； in: U ph is the phase voltage; Φ is the motor flux; f is the operating frequency; P M is the number of torque winding pole pairs; Combined with the motor support load requirements, the number of phase series conductors of the suspension winding is further calculated: ， ； in: P B is the number of pole pairs of the suspension winding; L B is the self-inductance of the suspension force winding; N M 、 N B are the equivalent turns of each phase winding in series of the torque winding and the suspension force winding respectively; is the flux linkage of each phase of the torque winding; F To support the load; i B is the maximum suspension current; r are the outer diameters of the motor rotor core respectively; S4. Stator parameter calculation: determined based on slot fill rate and wire diameter, including slot shape selection and stator size calculation.

9. The integrated design method for a five-degree-of-freedom magnetic levitation motor structure according to claim 8, characterized in that: After obtaining a design scheme of a bearingless permanent magnet motor by the design method of the bearingless permanent magnet motor, parameters such as the rotor weight and shaft diameter of the bearingless permanent magnet motor are used as input quantities of the design method of the axial-radial integrated magnetic bearing; The design method of the axial-radial integrated magnetic bearing comprises the following steps: P1. Coupled Magnetic Circuit Modeling: Considering the magnetic circuit coupling relationship between axial and radial magnetic bearings, the distributed magnetic circuit method is used to divide the air gap circumference of the magnetic bearing into blocks and multiple nodes to form multiple magnetic circuits. The magnetomotive force equation of the axial-radial integrated magnetic bearing is written based on the magnetic circuits. The air gap magnetic flux density is then iteratively calculated to establish a mapping relationship between magnetic bearing parameters and performance. P2. Calculation of magnetic bearing winding parameters: Calculate the number of turns of the magnetic bearing based on the air gap length and bias magnetic density and electrical density: ； in: N c is the number of turns of the magnetic bearing; B b is the bias flux density of the magnetic bearing; g 0 is the air gap length of the magnetic bearing; I b is the bias current of the magnetic bearing; P3. Calculation of magnetic bearing rotor size parameters: Calculate the rotor inner / outer diameter and length parameters based on the maximum allowable linear speed and magnetic pole width; P4. Calculation of magnetic bearing stator size parameters: Calculate the stator slot size parameters based on the number of turns, wire diameter and slot fill rate.

10. The integrated design method of the five-degree-of-freedom magnetic levitation motor structure according to claim 9, characterized in that: The design method for the bearingless permanent magnet motor and the design method for the axial-radial integrated magnetic bearing are designed in parallel and synchronously. After the two are completed, the design schemes obtained by the design method for the bearingless permanent magnet motor and the design method for the axial-radial integrated magnetic bearing are input into the calculation parameters of the design verification method through serial design; The design verification method includes four steps: electromagnetic calculation, temperature field calculation, dynamic calculation, and strength calculation. The method is used to respectively calculate the electromagnetic, temperature, dynamic, and strength performance of the five-degree-of-freedom magnetic levitation motor, and judge according to performance requirements until the requirements are met through iteration. Among them, the electromagnetic and temperature field calculations are serially calculated, and the electromagnetic and temperature field calculations, dynamic calculations, and strength calculations are parallel calculated.

Images