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

Abstract

The application provides a five-degree-of-freedom magnetic suspension motor structure and an integrated design method thereof, relates to the technical field of magnetic suspension motors, and is composed of a rotating shaft, a protective bearing, a displacement sensor, a bearingless permanent magnet motor, a machine shell, a shaft-radial integrated magnetic bearing and a rotary transformer. The motor structure adopts an integrated structure of one bearingless permanent magnet motor and one shaft-radial integrated magnetic bearing, achieves five-degree-of-freedom suspension of the motor, reduces the number of magnetic bearing components, reduces the volume of the motor, can significantly improve the power density of the motor, and has a wide application prospect in the field of high-speed rotating mechanical equipment. The integrated design method comprises a design method of the bearingless permanent magnet motor, a design method of the shaft-radial integrated magnetic bearing, and a design checking method. Through series-parallel hybrid collaborative design of different components and an accurate magnetic circuit calculation method, the motor design time is shortened, and the design efficiency is significantly improved.

Description

TECHNICAL FIELD

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

[0002] Magnetic levitation technology can realize high-speed, high-power density and low vibration and noise operation of the motor. Among them, the five-degree-of-freedom magnetic levitation motor refers to a motor system that can be actively levitated and controlled in five degrees of freedom. The five degrees of freedom include four radial degrees of freedom and one axial degree of freedom. It has the following advantages: no friction: since there is no mechanical contact between the rotor and the stator, friction and wear are eliminated, improving the efficiency and service life of the system; high precision: it can realize high-precision position and attitude control, and is suitable for occasions that require high-precision rotation; low energy consumption: compared with traditional mechanical bearings, magnetic levitation bearings reduce energy loss and improve the overall efficiency of the system; long service life: due to the reduction of mechanical wear, the service life of the system is significantly prolonged. At present, the five-degree-of-freedom magnetic levitation motor has been widely used in many technical fields, including aerospace, high-end equipment manufacturing, energy and power, and other key fields. In the prior art, two radial magnetic bearings and one axial magnetic bearing are mainly used to levitate the motor in five degrees of freedom, but there is a technical problem that the magnetic bearing is large in size, which is not conducive to the improvement of the critical speed and power density. At present, the bearingless motor technology as a new technology can place two sets of windings in one motor, while providing torque and suspension force, 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, both ends of the cylindrical solid permanent magnet are connected with the rotating shaft, the cylindrical solid permanent magnet is externally installed with a casing, the casing is fixedly installed with a stator core, a set of torque windings is embedded in the bottom layer of the stator core, two sets of suspension windings are embedded in the upper layer of the stator core, end covers are fixedly installed on both sides of the casing, auxiliary bearings are installed between the end covers and the rotating shaft, and passive permanent magnetic bearings are nested on the end covers and the rotating shaft. However, it adopts a topology structure design of "2 bearingless motors + 1 passive axial magnetic bearing", which has the technical defects of multiple motors, inability to actively control the axial direction, and low integration.

[0004] The invention patent with the publication number CN111211709A provides a five-degree-of-freedom magnetic suspension motor without thrust disc, which comprises a rotating shaft, a two-degree-of-freedom radial suspension assembly generating radial suspension force and having a rotor core coaxially assembled with the rotating shaft, a one-degree-of-freedom axial suspension assembly generating axial suspension force and having a rotor core coaxially assembled with the rotating shaft, a two-degree-of-freedom radial suspension bearingless motor assembly generating radial suspension force and capable of driving the rotating shaft to rotate, and an external stator yoke surrounding and supporting the two-degree-of-freedom radial suspension assembly, the one-degree-of-freedom axial suspension assembly and the two-degree-of-freedom radial suspension bearingless motor assembly. The annular permanent magnet of the two-degree-of-freedom radial suspension assembly and the annular permanent magnet of the one-degree-of-freedom axial suspension assembly are oppositely magnetized in the radial direction, forming a permanent magnetic bias magnetic field. However, the five-degree-of-freedom suspension of the motor is realized by the combination of "1 bearingless motor + 1 radial magnetic bearing + 1 axial magnetic bearing", and the diversified suspension supporting modes significantly increase the design and integration difficulty of the magnetic suspension motor, which is not conducive to the application of the magnetic suspension technology in high-speed rotating mechanical equipment. The motor structure also has the technical defects of multiple magnetic bearing components, complex process and low integration.

[0005] Therefore, it is necessary to study a five-degree-of-freedom magnetic suspension motor structure and an integrated design method thereof to solve the above technical problems. SUMMARY

[0006] In view of the technical problems in the background art that the magnetic bearing has a large volume, which is not conducive to the improvement of the critical speed and power density, and the diversified suspension supporting modes significantly increase the design and integration difficulty of the magnetic suspension motor, which is not conducive to the application of the magnetic suspension technology in high-speed rotating mechanical equipment, the present application provides a five-degree-of-freedom magnetic suspension motor structure and an integrated design method thereof. From the topological structure and design method, the power density and design efficiency of the magnetic suspension motor are further improved, which has important significance for the popularization and application of the magnetic suspension technology.

[0007] In the first aspect, the embodiments of the present application provide a five-degree-of-freedom magnetic suspension motor structure, which comprises a rotating shaft, and further comprises:

[0008] a bearingless permanent magnet motor generating suspension force in two radial degrees of freedom and capable of driving the rotating shaft to rotate;

[0009] a shaft-radial integrated magnetic bearing having the functions of radial magnetic bearing and axial magnetic bearing, generating suspension force in three degrees of freedom including two radial degrees of freedom and one axial degree of freedom;

[0010] the bearingless permanent magnet motor and the shaft-radial integrated magnetic bearing are respectively installed around the outer periphery of the rotating shaft on both sides, and are coaxially assembled with the rotating shaft;

[0011] the bearingless permanent magnet motor and the shaft-radial integrated magnetic bearing cooperate with each other to realize five-degree-of-freedom magnetic suspension.

[0012] As a further improvement of the present application, 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 which are in interference fit with each other.

[0013] After the radial magnetic bearing stator core is interference fit mounted on the right axial magnetic bearing stator core, the left axial magnetic bearing stator core and the right axial magnetic bearing stator core are fixedly assembled.

[0014] As a further improvement of the present application, the radial magnetic bearing stator core shares one magnetic bearing rotor with the left axial magnetic bearing stator core and the right axial magnetic bearing stator core.

[0015] As a further improvement of the present application, the axial-radial integrated magnetic bearing further comprises axial magnetic bearing stator windings and radial magnetic bearing stator windings; the axial magnetic bearing stator windings and the radial magnetic bearing stator windings are staggered arranged along the radial direction and are respectively arranged in upper and lower layers.

[0016] As a further improvement of the present application, the bearingless permanent magnet motor comprises a motor stator core, permanent magnets, a motor rotor, torque windings and suspension windings; the torque windings and the suspension windings are respectively embedded in upper and lower layers (or lower and upper layers) of motor slots in the motor stator core; the pole pair number of the torque windings and the suspension windings is different by 1.

[0017] As a further improvement of the present application, the five-degree-of-freedom magnetic levitation motor structure further comprises displacement sensors arranged at both ends and axial positions of the motor, a rotary transformer arranged at a non-extension end of the motor, protection bearings arranged at both sides of the motor, and a machine shell.

[0018] As a further improvement of the present application, the radial magnetic bearing stator core adopts one of 8-pole type, 12-pole type and 16-pole type, and adopts high-permeability low-loss silicon steel sheet material or high-permeability solid steel material; the left axial magnetic bearing stator core and the right axial magnetic bearing stator core adopt U-shaped structure or E-shaped structure and adopt high-permeability solid steel material; the magnetic bearing rotor adopts high-permeability low-loss silicon steel sheet or high-permeability solid steel material.

[0019] In the second aspect, the embodiment of the present application further provides an integrated design method of the five-degree-of-freedom magnetic levitation motor structure, which comprises three steps of a design method of a bearingless permanent magnet motor, a design method of an axial-radial integrated magnetic bearing, and a design checking method.

[0020] The specific steps of the design method of the bearingless permanent magnet motor are as follows:

[0021] S1, main dimension calculation: including bearingless permanent magnet motor main dimension calculation and air gap length calculation;

[0022] The bearingless permanent magnet motor main dimension is determined according to the input power:

[0023] ;

[0024] Wherein:

[0025] D i1 D is the inner diameter of the stator;

[0026] L ef L is the effective length of the core;

[0027] n N is the rated speed;

[0028] p 1 is the input power of the motor;

[0029] α p K is the calculated pole arc coefficient of the motor;

[0030] K nm K is the waveform coefficient of the air gap magnetic field;

[0031] K dp K is the motor fundamental winding coefficient;

[0032] A K is the torque winding electrical load;

[0033] B δ K is the magnetic flux density amplitude generated by the permanent magnet at the air gap;

[0034] The motor air gap length is determined according to the main dimension of the bearingless permanent magnet motor:

[0035] ;

[0036] Wherein: delta K is the motor air gap length;

[0037] S2, permanent magnet calculation: according to the air gap length and the working magnetic flux density, the thickness of the permanent magnet is calculated:

[0038] ;

[0039] Wherein:

[0040] mu 0 is the vacuum permeability;

[0041] H c Bm is coercive force of permanent magnet;

[0042] B Bm is working magnetic flux density;

[0043] S3, winding parameter calculation: according to motor magnetic flux, the number of phase series conductors of torque winding is calculated:

[0044] , ;

[0045] Wherein:

[0046] U ph V is phase voltage;

[0047] phi Bm is motor magnetic flux;

[0048] f f is working frequency;

[0049] P M Pm is the number of pole pairs of torque winding;

[0050] Combined with the requirement of motor supporting load, the number of phase series conductors of suspension winding is further calculated:

[0051] , ;

[0052] Wherein:

[0053] P B Pm is the number of pole pairs of suspension winding;

[0054] L B Ls is self-inductance of suspension force winding;

[0055] N M , N B Ns and Nt are respectively the number of series equivalent turns of each phase winding of torque winding and suspension force winding;

[0056] Ψm is each phase magnetic linkage of torque winding;

[0057] F W is supporting load;

[0058] i B Im is maximum suspension current;

[0059] rRespectively, motor rotor core outer diameter;

[0060] S4, stator parameter calculation: according to the slot fill rate and wire diameter determination, including the selection of slot shape and stator size calculation.

[0061] As a further improvement of the application, after obtaining the design scheme of the 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 taken as the input of the design method of the shaft-radial integrated magnetic bearing;

[0062] The design method of the shaft-radial integrated magnetic bearing comprises the following steps:

[0063] P1, coupling magnetic circuit modeling: considering the magnetic circuit coupling relationship of the shaft and radial magnetic bearing, the magnetic bearing air gap circumference is divided into multiple nodes by using the distributed magnetic circuit method, forming multiple magnetic loops, the magnetic motive force equation of the shaft-radial integrated magnetic bearing is written according to the magnetic loop, and then the air gap magnetic density is iteratively calculated to establish the mapping relationship between the magnetic bearing parameters and performance;

[0064] P2, magnetic bearing winding parameter calculation: according to the air gap length and bias magnetic density and electric density, the number of turns of the magnetic bearing is calculated:

[0065] ;

[0066] Wherein:

[0067] N c The number of turns of the magnetic bearing;

[0068] B b The bias magnetic density of the magnetic bearing;

[0069] g 0 is the air gap length of the magnetic bearing;

[0070] I b The bias current of the magnetic bearing;

[0071] P3, magnetic bearing rotor size parameter calculation: according to the maximum allowable linear speed and magnetic pole width, the inner and outer diameters and length parameters of the rotor are calculated;

[0072] P4, magnetic bearing stator size parameter calculation: according to the number of turns, wire diameter and slot fill rate, the stator slot size parameters are calculated.

[0073] As a further improvement of the present application, 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 end of the two, through serial design, the design scheme obtained by the design method of the bearingless permanent magnet motor and the design method of the axial-radial integrated magnetic bearing is input into the calculation parameters of the design checking method.

[0074] The design checking method comprises electromagnetic calculation, temperature field calculation, dynamics calculation and strength calculation; the electromagnetic, temperature, dynamics and strength performances of the five-degree-of-freedom magnetic levitation motor are calculated respectively, and the performance requirements are judged until the iteration meets the requirements. Wherein, the electromagnetic and temperature field calculation adopts serial calculation, and the dynamics calculation and the strength calculation adopt parallel calculation.

[0075] The working principle of the five-degree-of-freedom magnetic levitation motor structure provided by the present application is that:

[0076] The five-degree-of-freedom magnetic levitation motor structure is mainly integrated by a bearingless permanent magnet motor, an axial-radial integrated magnetic bearing and the like. Among them, the bearingless permanent magnet motor increases a set of suspension winding on the basis of the traditional torque winding, generates two radial degrees of suspension force through magnetic field modulation. The axial-radial integrated magnetic bearing adopts common rotor, winding cross arrangement and the like for integration, and has the functions of axial magnetic bearing and radial magnetic bearing, providing two radial degrees of suspension force and one axial degree of suspension force for the magnetic levitation motor structure. The bearingless permanent magnet motor and the axial-radial integrated magnetic bearing cooperate with each other to realize five-degree-of-freedom magnetic levitation. In addition, the displacement sensor measures the displacement signal for the suspension control of the magnetic levitation motor; the rotary transformer measures the rotation speed signal for the rotation control of the magnetic levitation motor; the protection bearing is used to protect the rotor of the magnetic levitation motor structure from direct contact with the stator when falling. Thus, the above-mentioned components are cooperated with each other to jointly build the integrated structure of the five-degree-of-freedom magnetic levitation motor. The five-degree-of-freedom magnetic levitation motor structure adopts one bearingless permanent magnet motor and one axial-radial integrated magnetic bearing, compared with the five-degree-of-freedom magnetic levitation motor in the prior art, the number of suspension components is reduced, the space utilization is improved, and the five-degree-of-freedom active control, small size and high integration are realized.

[0077] Beneficial effects:

[0078] 1. The five-degree-of-freedom magnetic levitation motor structure provided by the application adopts a bearingless permanent magnet motor plus a shaft-radial integrated magnetic bearing structure, achieves five-degree-of-freedom suspension of the motor, reduces the number of magnetic bearing components, and significantly reduces the volume of the motor by means of common rotor and winding staggered arrangement design methods. The volume is at least reduced by more than 20% compared with a conventional magnetic levitation motor, has the characteristics of high structural integration and efficient design method, can significantly improve the power density and design efficiency of the motor, and has a wide application prospect in the field of high-speed rotating mechanical equipment.

[0079] 2. The five-degree-of-freedom magnetic levitation motor structure provided by the application adopts common rotor and winding staggered arrangement technology for the shaft-radial integrated magnetic bearing, shortens the axial length of the motor, and improves the system integration; and by means of the inner and outer rotor structure of the magnetic bearing, the rotor eddy current loss at high speed can be reduced, thereby the working efficiency of the motor can be improved.

[0080] 3. The integrated design method of the five-degree-of-freedom magnetic levitation motor structure provided by the application adopts a distributed magnetic circuit method to model the shaft-radial coupled magnetic circuit of the shaft-radial integrated magnetic bearing, which is used to establish the relationship between the performance and parameters of the magnetic bearing, and significantly improves the design efficiency of the magnetic bearing.

[0081] 4. The integrated design method of the five-degree-of-freedom magnetic levitation motor structure provided by the application, first, the design of the bearingless permanent magnet motor is carried out, after obtaining the design scheme of the bearingless permanent magnet motor, the rotor weight, shaft diameter and other parameters of the bearingless permanent magnet motor are taken as the input quantity of the shaft-radial integrated magnetic bearing design method to design the shaft-radial integrated magnetic bearing, finally, the design scheme of the bearingless permanent magnet motor and the design scheme of the shaft-radial integrated magnetic bearing are input into the design checking method to realize the collaborative design of the bearingless permanent magnet motor and the shaft-radial integrated magnetic bearing under the multi-disciplinary checking method, and the design efficiency of the magnetic levitation motor is improved.

[0082] The above description is only a summary of the technical solutions of the application, in order to more clearly understand the technical means of the application, the specific embodiments of the application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following will specifically describe the embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0083] In order to more clearly illustrate the technical solutions of the application, the following will briefly introduce the drawings used in the application. Obviously, the drawings described below are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0084] Figure 1A schematic diagram of a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present application;

[0085] Figure 2 A schematic diagram of a bearingless permanent magnet motor in a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present application;

[0086] Figure 3 A schematic diagram of an axial-radial integrated magnetic bearing in a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present application;

[0087] Figure 4 A flowchart of an integrated design method of a five-degree-of-freedom magnetic levitation motor structure provided by an embodiment of the present application;

[0088] The same reference numerals are used in all the drawings to denote the same components or structures, and the letters denote the difference in the mounting positions, wherein the respective reference numerals are as follows:

[0089] 10, five-degree-of-freedom magnetic levitation motor structure; 11, rotating shaft; 12, protection bearing; 13, displacement sensor; 14, bearingless permanent magnet motor; 15, motor 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;

[0090] 20, integrated design method of a five-degree-of-freedom magnetic levitation motor structure; 21, design method of a bearingless permanent magnet motor; 22, design method of an axial-radial integrated magnetic bearing; 23, design checking method (multidisciplinary checking method). DETAILED DESCRIPTION

[0091] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0092] Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as those commonly understood by the person skilled in the art to which the present application belongs; the terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "comprise" and "have" and any variations thereof in the specification and claims of the present application and the above description of the drawings are intended to cover the non-exclusive inclusion.

[0093] In the description of the embodiments of the present application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0094] In this paper, the reference to "embodiments" means that the specific features, structures or properties described in conjunction with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0095] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0096] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0097] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0098] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0099] In order to solve the technical problems of the magnetic bearing in the prior art, that is, the volume is large, and it is not conducive to the improvement of the critical speed and power density, the application provides a five-degree-of-freedom magnetic suspension motor structure and an integrated design method thereof. From the topological structure and the design method, a bearingless permanent magnet motor and an axial-radial integrated magnetic bearing are adopted. While the five-degree-of-freedom suspension of the motor is realized, the power density and the design efficiency of the magnetic suspension motor are further improved through the design methods such as sharing the rotor and cross arrangement of the winding. The application has important significance for the popularization and application of the magnetic suspension technology.

[0100] Embodiment 1

[0101] Please refer to Figures 1 to 3 The embodiment 1 of the application provides a five-degree-of-freedom magnetic suspension motor structure 10, which mainly comprises a rotating shaft 11, a protection bearing 12, a displacement sensor 13, a bearingless permanent magnet motor 14, a motor shell 15, an axial-radial integrated magnetic bearing 16, a rotary transformer 17 and the like.

[0102] The bearingless permanent magnet motor 14 generates suspension forces of two radial degrees of freedom, and can drive the rotating shaft 11 to rotate.

[0103] The axial-radial integrated magnetic bearing 16 has the functions of the radial magnetic bearing and the axial magnetic bearing, and generates suspension forces of three degrees of freedom, that is, two radial degrees of freedom and one axial degree of freedom.

[0104] The bearingless permanent magnet motor 14 and the axial-radial integrated magnetic bearing 16 are respectively installed around the outer periphery of the rotating shaft 11 on both sides, 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 realize five-degree-of-freedom magnetic suspension.

[0105] Please refer to Figure 1 and Figure 3 The bearingless permanent magnet motor 14 mainly comprises a motor stator core 141, torque windings 142 and suspension windings 143, permanent magnets 144, a motor rotor 145 and the like. The torque windings 142 and the suspension windings 143 are respectively embedded in the upper and lower two layers in the motor slot.

[0106] The pole pair number of the torque windings 142 and the suspension windings 143 is different by 1. The magnetic field generated by the suspension windings 143 modulates the original balance magnetic field of the motor, so that the motor rotor 145 is subjected to a radial force to realize self-suspension. Therefore, the bearingless permanent magnet motor 14 provides suspension forces of two radial degrees of freedom for the five-degree-of-freedom magnetic suspension motor structure 10.

[0107] Please refer to Figure 1 and Figure 2As shown, the axial-radial integrated magnetic bearing 16 mainly comprises a left axial magnetic bearing stator core 161, a radial magnetic bearing stator core 162, axial magnetic bearing stator windings 163 and radial magnetic bearing stator windings 164, a magnetic bearing rotor 165, a right axial magnetic bearing stator core 166 and other component structures.

[0108] The axial magnetic bearing stator windings 163 and the radial magnetic bearing stator windings 164 are arranged in a staggered manner along the radial direction and are respectively arranged in the upper and lower two layers.

[0109] In some embodiments, the magnetic bearing rotor 165 is fixed on the rotating shaft 11 by a shrink fit, and after the radial magnetic bearing stator core 162 is shrink fitted on the right axial magnetic bearing stator core 166, the left axial magnetic bearing stator core 161 and the right axial magnetic bearing stator core 166 are assembled by bolts.

[0110] In the axial-radial integrated magnetic bearing 16, the radial magnetic bearing stator core 162 shares the 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 simultaneously has the functions of radial magnetic bearing and axial magnetic bearing, and provides two radial degrees of freedom and one axial degree of freedom of suspension force for the five-degree-of-freedom magnetic levitation motor structure 10.

[0111] The magnetic bearing rotor 165 is fixed on the rotating shaft 11 and comprises a magnetic bearing inner rotor 1651 and a magnetic bearing outer rotor 1652 which are in interference fit with each other.

[0112] In some embodiments, the radial magnetic bearing stator core 162 adopts one of 8-pole type, 12-pole type and 16-pole type and adopts high-permeability low-loss silicon steel sheet material; the left axial magnetic bearing stator core 161 and the right axial magnetic bearing stator core 166 adopt U-shaped structure or E-shaped structure and adopt high-permeability solid steel material; and the magnetic bearing rotor 165 adopts high-permeability low-loss silicon steel sheet or high-permeability solid steel material.

[0113] Please refer to Figure 1 As shown, the displacement sensor 13 is arranged at both ends of the motor and at an axial position to measure the displacement of the rotating shaft 11 in different directions, which is used for suspension control of the five-degree-of-freedom magnetic levitation motor structure 10.

[0114] The rotary transformer 17 is arranged at a non-extension end of the motor to measure the rotating speed of the motor, which is used for rotation control of the five-degree-of-freedom magnetic levitation motor structure 10.

[0115] The protective bearing 12 is arranged at both sides of the motor to protect the rotor when it falls.

[0116] The overall volume of the above-mentioned integrated five-degree-of-freedom magnetic levitation motor structure 10 provided by embodiment 1 is at least 20% smaller than that of a conventional magnetic levitation motor, thereby having extremely high integration. Compared with the conventional magnetic levitation motor, the motor performance is that the number of suspension components is small, the space utilization rate is high, which indicates that the integration and power density are higher, the performance is improved, and the power density is inversely proportional to the volume and speed.

[0117] Embodiment 2

[0118] Please refer to Figure 4 The embodiment 2 of the present application provides an integrated design method 20 of the above-mentioned five-degree-of-freedom magnetic levitation motor structure, which mainly includes three design steps of a bearingless permanent magnet motor design method 21, a shaft-radial integrated magnetic bearing design method 22, and a design checking method (multidisciplinary checking method) 23.

[0119] Among them, the specific design process of the bearingless permanent magnet motor design method 21 in the design step 1 is as follows:

[0120] S1, main size calculation: including bearingless permanent magnet motor 14 main size calculation and air gap length calculation; the main size of the bearingless permanent magnet motor 14 is determined according to the input power:

[0121] ;

[0122] Among them:

[0123] D i1 D is the inner diameter of the stator;

[0124] L ef L is the effective length of the core;

[0125] n N is the rated speed;

[0126] p 1 is the input power of the motor;

[0127] α p K is the calculated pole arc coefficient of the motor;

[0128] K nm K is the waveform coefficient of the air gap magnetic field;

[0129] K dp K is the fundamental winding coefficient of the motor;

[0130] A K is the torque winding 142 electric load;

[0131] B δ is the magnetic flux density amplitude generated by the permanent magnets 144 at the air gap;

[0132] The motor air gap length is determined according to the main dimensions of the bearingless permanent magnet motor 14:

[0133] ;

[0134] wherein: delta is the motor air gap length;

[0135] S2, Permanent magnet 144 calculation: according to the air gap length and the working magnetic flux density, the thickness of the permanent magnet 144 is calculated:

[0136] ;

[0137] wherein:

[0138] mu 0 is the vacuum permeability;

[0139] H c is the coercive force of the permanent magnet 144;

[0140] B 0 is the working magnetic flux density;

[0141] S3, winding parameter calculation: according to the motor magnetic flux, the phase series conductor number of the torque winding 142 is calculated:

[0142] , ;

[0143] wherein:

[0144] U ph is the phase voltage;

[0145] phi is the motor magnetic flux;

[0146] f is the working frequency;

[0147] P M is the pole pair number of the torque winding 142;

[0148] Combined with the motor supporting load requirement, the phase series conductor number of the suspension winding 143 is further calculated:

[0149] , ;

[0150] wherein:

[0151] P B number of pole pairs of the suspension winding 143;

[0152] L B self-inductance of the suspension winding 143;

[0153] N M , N B number of equivalent turns in series for each phase winding of the torque winding 142 and the suspension winding 143, respectively;

[0154] flux linkage of each phase of the torque winding 142;

[0155] F supported load;

[0156] i B maximum suspension current;

[0157] r outer diameter of the motor rotor core, respectively;

[0158] S4, stator parameter calculation: determined according to the slot fill factor and the wire diameter, including the selection of the slot shape and the calculation of the stator size.

[0159] Step 2, after obtaining the design scheme of the bearingless permanent magnet motor 14 by 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 taken as the input quantities of the design method 22 of the shaft-radial integrated magnetic bearing; the design method 22 of the shaft-radial integrated magnetic bearing includes the following design process:

[0160] P1, coupled magnetic circuit modeling: considering the magnetic circuit coupling relationship of the shaft and radial magnetic bearing, the distributed magnetic circuit method is used to divide the air gap circumference of the magnetic bearing into multiple nodes to form multiple magnetic circuits, the magnetic motive force equation of the shaft-radial integrated magnetic bearing is written according to the magnetic circuit, and then the air gap magnetic density is iteratively calculated to establish the mapping relationship between the magnetic bearing parameters and the performance;

[0161] P2, magnetic bearing winding parameter calculation: according to the air gap length and the bias magnetic density and the electric density, the number of turns of the magnetic bearing is calculated:

[0162] ;

[0163] wherein:

[0164] N c number of turns of the magnetic bearing;

[0165] Bb is the bias flux density of the magnetic bearing;

[0166] g 0 is the air gap length of the magnetic bearing;

[0167] I b is the bias current of the magnetic bearing;

[0168] P3, magnetic bearing rotor size parameter calculation: according to the maximum allowable linear speed, magnetic pole width, the inner and outer diameters of the rotor, length parameters are calculated;

[0169] P4, magnetic bearing stator size parameter calculation: according to the number of turns, wire diameter and slot fill rate, the stator slot type size parameters are calculated.

[0170] Step 3 of the design, input the design scheme obtained by the design method 21 of the bearingless permanent magnet motor and the design method 22 of the shaft-radial integrated magnetic bearing into the calculation parameters of the design checking method 23;

[0171] The design checking method 23 includes four checking processes of electromagnetic calculation, temperature field calculation, dynamics calculation and strength calculation, which are used to calculate the electromagnetic, temperature, dynamics and strength performance of the five-degree-of-freedom magnetic suspension motor respectively, and to judge according to the performance requirements until iteration to meet the requirements, so as to ensure the feasibility of the scheme.

[0172] In some specific embodiments, the design method 21 of the bearingless permanent magnet motor and the design method 22 of the shaft-radial integrated magnetic bearing, and the design checking method 23 can obtain a magnetic suspension motor scheme that meets multiple performance requirements such as electromagnetic, temperature, dynamics and strength in a short time. The main design parameters of embodiment 2 are shown in Table 1 and Table 2:

[0173] Table 1 Main design parameters of bearingless permanent magnet motor 14

[0174]

[0175] Table 2 Main design parameters of shaft-radial integrated magnetic bearing 16

[0176]

[0177] Therefore, by integrating the design data and scheme of the above three design steps, a five-degree-of-freedom magnetic suspension motor structure 10 is designed, which further improves the power density and design efficiency of the magnetic suspension motor from the topological structure and design method, and has important significance for the popularization and application of magnetic suspension technology.

[0178] The 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 application are not limited to the specific parameter data in Embodiment 2, and the specific parameters can also be designed and checked according to actual application or special application requirements.

[0179] In summary, the application provides a five-degree-of-freedom magnetic levitation motor structure and an integrated design method thereof, relates to the technical field of magnetic levitation motors, and is composed of a rotating shaft, a protective bearing, a displacement sensor, a bearingless permanent magnet motor, a machine shell, an axial-radial integrated magnetic bearing, a rotary transformer and the like. The integrated structure of one bearingless permanent magnet motor plus one axial-radial integrated magnetic bearing reduces the number of magnetic bearing components and the size of the motor while achieving five-degree-of-freedom levitation of the motor. The motor structure has the characteristics of high structural integration and efficient design method, can significantly improve the power density and design efficiency of the motor, and has a wide application prospect in the field of high-speed rotating mechanical equipment; and effectively overcomes the technical defects of the prior art that the magnetic bearing is large in size and is not conducive to the improvement of the critical speed and power density.

[0180] It should be noted that the application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and the same effect as the application within the scope of the technical solution of the application are included in the technical scope of the application. In addition, within the scope of the main idea of the application, various modifications that can be thought of by those skilled in the art, other ways constructed by combining part of the components in the embodiments are also included in the scope of the application.

Claims

1. A method of integrated design of a five-degree-of-freedom magnetic levitation motor structure comprising a rotating shaft, characterized in that, The five-degree-of-freedom magnetic suspension motor structure further comprises: The bearingless permanent magnet motor generates suspension forces of two radial degrees of freedom and can drive the rotation of the rotating shaft; The shaft-radial integrated magnetic bearing has the functions of radial magnetic bearing and axial magnetic bearing, generates suspension forces of three degrees of freedom of two radial degrees of freedom and one axial degree of freedom; The bearingless permanent magnet motor and the shaft-radial integrated magnetic bearing are respectively installed around the outer periphery of the rotating shaft on both sides and are coaxially assembled with the rotating shaft; The bearingless permanent magnet motor and the shaft-radial integrated magnetic bearing cooperate with each other to jointly realize five-degree-of-freedom magnetic suspension; The integrated design method of the five-degree-of-freedom magnetic suspension motor structure comprises three steps of a design method of the bearingless permanent magnet motor, a design method of the shaft-radial integrated magnetic bearing, and a design checking method; The specific steps of the design method of the bearingless permanent magnet motor are as follows: S1, main size calculation: including main size calculation and air gap length calculation of the bearingless permanent magnet motor; the main size of the bearingless permanent magnet motor is determined according to the input power: ； Wherein: D i1 D is the inner diameter of the stator L ef Lc is the effective length of the core; n N is the rated speed; p 1 is the input power of the electric machine; α p to calculate the pole arc factor of the electric machine; K nm the waveform coefficient of the air gap magnetic field; K dp For the fundamental winding factor of the motor; A for torque winding electrical load; B δ is the amplitude of the magnetic flux density generated by the permanent magnets at the air gap; The motor air gap length is determined according to the main size of the bearingless permanent magnet motor: ； wherein: δ is the air gap length of the electric machine; S2, permanent magnet calculation: calculating the thickness of the permanent magnet according to the air gap length and the working magnetic density: ； Wherein: μ 0 is the vacuum permeability; H c the coercive force of the permanent magnet; B 0 is the working magnetic flux density; S3, winding parameter calculation: calculating the phase series conductor number of the torque winding according to the motor magnetic flux: ， ； Wherein: U ph Vph is the phase voltage; Φ for the magnetic flux of the electric machine; f f is the operating frequency; P M for torque winding pole pairs; Further calculating the phase series conductor number of the suspension winding in combination with the motor support load requirement: ， ； Wherein: P B Number of pole pairs for a suspended winding L B For the suspended force winding self-induction; N M , N B Nsand Nsrespectively the number of series equivalent turns per phase winding of the torque winding and of the suspension force winding. flux per phase for torque winding; F to support loads; i B Maximum suspended current; r respectively the outer diameter of the motor rotor core; S4, stator parameter calculation: determining according to the slot fill rate and wire diameter, including the selection of the slot shape and the calculation of the stator size.

2. The integrated design method of five degrees of freedom magnetic levitation motor structure according to claim 1, characterized in that, The shaft-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 in mutual interference fit; After the radial magnetic bearing stator core is interference-fitted and installed on the right axial magnetic bearing stator core, the left axial magnetic bearing stator core and the right axial magnetic bearing stator core are fixedly assembled.

3. The integrated design method of five degrees 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 one magnetic bearing rotor.

4. The method of claim 2, wherein, The shaft-radial integrated magnetic bearing further comprises axial magnetic bearing stator windings and radial magnetic bearing stator windings; the axial magnetic bearing stator windings and the radial magnetic bearing stator windings are arranged in a radial direction and are arranged as upper and lower layers.

5. The method of claim 1, wherein, The bearingless permanent magnet motor comprises a motor stator core, permanent magnets, a motor rotor, torque windings, and suspension windings; the torque windings and the suspension windings are respectively embedded in upper and lower layers of motor slots of the motor stator core, or the torque windings and the suspension windings are respectively embedded in lower and upper layers of motor slots of the motor stator core; the pole pair number of the torque windings and the suspension windings differs by 1.

6. The method of claim 1, wherein, The five-degree-of-freedom magnetic suspension motor structure further comprises displacement sensors arranged at both ends and axial positions of the motor, a rotary transformer arranged at a non-extension end position of the motor, protection bearings arranged at both sides of the motor, and a machine housing.

7. The method of claim 2, wherein, The radial magnetic bearing stator core adopts one of 8-pole type, 12-pole type and 16-pole type, and adopts high-permeability low-loss silicon steel sheet material or high-permeability solid steel material; the left axial magnetic bearing stator core and the right axial magnetic bearing stator core adopt U-shaped structure or E-shaped structure, and adopt high-permeability solid steel material; the magnetic bearing rotor adopts high-permeability low-loss silicon steel sheet or high-permeability solid steel material.

8. The method of claim 1, wherein, After obtaining the design scheme of the bearingless permanent magnet motor through the design method of the bearingless permanent magnet motor, the rotor weight, shaft diameter and other parameters of the bearingless permanent magnet motor are taken as input quantities of the design method of the shaft-radial integrated magnetic bearing; The design method of the shaft-radial integrated magnetic bearing comprises the following steps: P1, coupling magnetic circuit modeling: considering the magnetic circuit coupling relationship of the axial and radial magnetic bearings, the magnetic bearing air gap circumference is processed by block, divided into multiple nodes, multiple magnetic circuits are formed, the magnetic motive force equation of the shaft-radial integrated magnetic bearing is written according to the magnetic circuit, then the air gap magnetic density is iteratively calculated, and the mapping relationship between the magnetic bearing parameters and performance is established; P2, magnetic bearing winding parameter calculation: according to the air gap length and bias magnetic density and electric density, the number of turns of the magnetic bearing is calculated: ； P3, magnetic bearing rotor size parameter calculation: according to the maximum allowable linear speed and magnetic pole width, the inner / outer diameter and length parameters of the rotor are calculated; N c the number of turns of the magnetic bearing; B b biasing the magnetic flux density of the magnetic bearing; g 0 is the air gap length of the magnetic bearing; I b bias current for the magnetic bearing; P4, magnetic bearing stator size parameter calculation: according to the number of turns, wire diameter and slot fill rate, the stator slot type size parameters are calculated. The design method of the bearingless permanent magnet motor and the design method of the shaft-radial integrated magnetic bearing are designed in parallel, and after the two methods are completed, the design schemes obtained by the design method of the bearingless permanent magnet motor and the design method of the shaft-radial integrated magnetic bearing are input into the calculation parameters of the design checking method through serial design; 9. The integrated design method of five degrees of freedom magnetic levitation motor structure according to claim 8, characterized in that, The design checking method comprises four steps of electromagnetic calculation, temperature field calculation, dynamics calculation and strength calculation, which are used to calculate the electromagnetic, temperature, dynamics and strength performance of the five-degree-of-freedom magnetic levitation motor respectively, and the performance requirements are judged until the requirements are met through iteration; wherein the electromagnetic and temperature field calculation adopts serial calculation, and the electromagnetic and temperature field calculation and the dynamics calculation and the strength calculation adopt parallel calculation. ​

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