CN115580043A

CN115580043A - Electric machine

Info

Publication number: CN115580043A
Application number: CN202211284530.4A
Authority: CN
Inventors: 李琦; 范涛; 温旭辉; 王佐梁; 孙承旭; 李晔
Original assignee: Institute of Electrical Engineering of CAS
Current assignee: Institute of Electrical Engineering of CAS
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2023-01-06

Abstract

The invention discloses a motor, which comprises a stator, a coil winding and a rotor; the stator comprises a stator core, wherein the stator core is provided with a stator yoke part and a plurality of first stator teeth and a plurality of second stator teeth which are respectively arranged on the radial inner side and the radial outer side of the stator yoke part in a protruding mode; the plurality of first stator teeth and the stator yoke portion are arranged in an encircling mode to form a plurality of inner side grooves, and the plurality of second stator teeth and the stator yoke portion are arranged in an encircling mode to form a plurality of outer side grooves; a plurality of coil windings are respectively wound on the stator yoke parts between the inner side slots and the outer side slots; the stator is arranged around the rotor, or the rotor is arranged around the stator; defining the number of inner slots and outer slots as N, which satisfies the relation: n = N × m × p; wherein n is a positive integer, m is the number of phases of the coil winding, and P is the number of poles of the motor. The invention improves the stator structure of the motor, is suitable for high-speed driving application occasions in flat space, and realizes the compact design of the permanent magnet motor for low-pole-number high-speed driving occasions.

Description

Electric machine

Technical Field

The invention relates to the technical field of back-wound winding permanent magnet motors, in particular to a motor.

Background

The motor generally includes a stator and a rotor, the stator includes a stator core and a coil winding wound on the stator core, the rotor includes a rotating shaft and a rotor core sleeved on the rotating shaft, and a permanent magnet is disposed at an outer edge of the rotor core.

In a high-speed driving occasion, the permanent magnet motor is high in running speed, high in frequency and low in pole number, and an integer slot winding is adopted mostly. The integral slot winding motor with low pole number inevitably faces the difficult problems of long winding end and poor heat dissipation. In the high-speed driving application occasion of flat space, the pole number of the motor is low, because the axial dimension of the motor is short, the axial effective length of the permanent magnet motor with the conventional structure is far shorter than the length of the end part of the winding, the end part of the winding is longer, the loss of the end part of the winding accounts for most of the copper loss, the space occupied by the end part of the winding and the heat dissipation problem of the end part of the winding limit the power size and the power density of the motor with the conventional structure.

Disclosure of Invention

The invention mainly aims to provide a motor, aiming at realizing compact design of a permanent magnet motor for low-pole-number high-speed driving occasions.

To achieve the above object, the present invention provides a motor including:

a stator including a stator core having a stator yoke and a plurality of first stator teeth and a plurality of second stator teeth that are respectively provided to protrude from the stator yoke to a radial inner side and a radial outer side thereof; the first stator teeth and the stator yoke are arranged in an encircling mode to form a plurality of inner side slots, and the second stator teeth and the stator yoke are arranged in an encircling mode to form a plurality of outer side slots;

a plurality of coil windings wound around the stator yoke between the inner slots and the outer slots, respectively; and

a rotor, the stator disposed around the rotor, or the rotor disposed around the stator;

defining the number of the inner slots and the outer slots to be N, and satisfying the relation: n = N × m × p; wherein n is a positive integer, m is the number of phases of the coil winding, and P is the number of poles of the motor.

Defining the stator core lamination length of the motor as Le, and satisfying the relation:

and Do is the outer diameter of the stator, and kd is the ratio of the inner diameter to the outer diameter of the stator.

Optionally, the stator core includes a plurality of core modules, and two adjacent core modules are connected through a mortise-tenon joint structure.

Optionally, the number of the iron core modules is equal to the number of poles of the motor; or alternatively

The number of the iron core modules is half of the number of poles of the motor.

Optionally, the number of the first stator teeth, the second stator teeth and the stator yoke on each of the core modules is n × m; or

The number of the first stator teeth, the second stator teeth and the stator yoke portions on each of the core modules is 2 x n x m.

Optionally, the first stator teeth, the second stator teeth and the stator yoke are made of oriented silicon steel; the orientation direction of the first stator tooth and the second stator tooth is the tooth height direction; the stator yoke part is in a trapezoidal arrangement, and the orientation direction of the stator yoke part is parallel to the upper bottom edge and the lower bottom edge of the stator yoke part.

Optionally, the rotor includes a rotor core and a magnetic steel, and the magnetic steel is attached to the rotor core; or

The magnetic steel is at least partially embedded in the rotor core.

Optionally, the motor further includes a rotating shaft, and the rotor is sleeved on the rotating shaft.

Optionally, the motor further includes a casing sleeved on the stator, and a gap between the coil winding and the casing and between the coil winding and the stator core is filled with a heat-conducting potting material.

Optionally, the cross-sectional area of the inner slot is equal to the cross-sectional area of the outer slot.

In the technical scheme of the invention, the motor comprises a stator, a coil winding and a rotor; the stator comprises a stator core, wherein the stator core is provided with a stator yoke part and a plurality of first stator teeth and a plurality of second stator teeth which are respectively arranged on the radial inner side and the radial outer side of the stator yoke part in a protruding mode; the plurality of first stator teeth and the stator yoke portion are arranged in an encircling mode to form a plurality of inner side grooves, and the plurality of second stator teeth and the stator yoke portion are arranged in an encircling mode to form a plurality of outer side grooves; a plurality of coil windings are respectively wound on the stator yoke parts between the inner side slots and the outer side slots; the stator is arranged around the rotor, or the rotor is arranged around the stator; defining the number of inner slots and outer slots as N, which satisfies the relation: n = N × m × p; wherein n is a positive integer, m is the number of phases of the coil winding, and P is the number of poles of the motor. So for motor structure is compacter, has also promoted the convenience of motor equipment simultaneously.

In addition, the motor is suitable for high-speed driving application occasions in flat space, and compact design of the permanent magnet motor for low-pole-number high-speed driving occasions is achieved.

In a conventional permanent magnet motor, the motor coil winding can be regarded as a runway, so that the actual length of the winding in one stator slot can be expressed as:

wherein Le is the iron core length, do is the stator outer diameter, kd is the ratio of the stator inner diameter to the stator outer diameter, and p is the number of poles of the motor.

However, for the back-wound permanent magnet machine of the present invention, it is also assumed that the coil windings are in the form of runways, and therefore the actual length of the windings in one stator slot can be expressed as:

wherein Le is the iron core stacking length, do is the outer diameter of the stator, and Di is the inner diameter of the stator.

Through comparative analysis, it can be known that the stator lamination length Le is under the constraint of a flat space through L2< L1, the back-wound winding disclosed by the invention is superior to a conventional motor winding structure, and the constraint condition of the flat space is as follows:

in other words, compared with the conventional motor, the motor of the invention can achieve the same performance with the shorter effective length of the iron core, has more compact structure and can meet the performance requirement of high-speed driving application occasions in flat space. Under the condition that the size of the flat space is fixed, the power size and the power density of the motor are higher compared with those of a conventional motor with the same volume.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of an electric machine according to the present invention;

fig. 2 is a schematic structural diagram of a stator core in an embodiment of an electric machine according to the present invention;

fig. 3 is a schematic structural diagram of a stator core module according to an embodiment of the motor of the present invention;

fig. 4 is a schematic structural diagram of a stator core module in another embodiment of the motor of the present invention.

The reference numbers illustrate:

10. a stator; 20. a coil winding; 30. a rotor; 11. a stator yoke; 12. a first stator tooth; 13. a second stator tooth; 10a, an inner side groove; 10b, an outer groove; 110. an iron core module; 31. a rotor core; 32. magnetic steel; 33. a rotating shaft; 40. a housing; 40a, cooling channels.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, if appearing throughout the text, "and/or" is meant to include three juxtaposed aspects, taking "a and/or B" as an example, including either the a aspect, or the B aspect, or both the a and B aspects. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The invention provides a motor, in particular to a back-wound winding permanent magnet motor, which can be applied to the fields of new energy automobiles, rail transit, electric aviation and the like, and is not limited in the field.

Referring to fig. 1 and 2, in an embodiment of the present invention, the motor includes a stator 10, a coil winding 20, and a rotor 30; the stator 10 includes a stator core having a stator yoke 11 and a plurality of first stator teeth 12 and a plurality of second stator teeth 13 protruding from the stator yoke 11 to the radial inner side and the radial outer side thereof, that is, the first stator teeth 12 and the second stator teeth 13 are arranged back to back; wherein, a plurality of inner slots 10a are formed by the first stator teeth 12 and the stator yoke 11, and a plurality of outer slots 10b are formed by the second stator teeth 13 and the stator yoke 11; a plurality of coil windings 20 wound around the stator yoke 11 between the inner slots 10a and the outer slots 10b, respectively; the stator 10 is disposed around the rotor 30, or the rotor 30 is disposed around the stator 10, that is, the rotor 30 may be an inner rotor, or an outer rotor, and this is not limited herein.

The number of inner slots 10a and outer slots 10b is defined as N, which satisfies the relation: n = N × m × p; where n is a positive integer, m is the number of phases of the coil winding 20, and P is the number of poles of the motor.

In this embodiment, the rotor 30 includes a rotor core 31 and a magnetic steel 32, the magnetic steel 32 is attached to the rotor core 31, or at least a part of the magnetic steel 32 is embedded in the rotor core 31, that is, the magnetic steel 32 may be surface-attached, surface-embedded, or embedded, which is not limited herein.

Referring to fig. 1, in this embodiment, the motor may further include a rotating shaft 33, and the rotor 30 is sleeved on the rotating shaft 33 to rotate the rotor 30.

For better motor performance, in the present embodiment, the cross-sectional area of the inner slot 10a and the cross-sectional area of the outer slot 10b may be set to be equal, but not limited thereto.

The motor is suitable for high-speed driving application occasions in flat spaces, and compact design of the permanent magnet motor for low-pole-number high-speed driving occasions is achieved.

In a conventional permanent magnet motor, the motor coil winding 20 can be seen as a racetrack, so the actual length of the winding in one stator slot can be expressed as:

where Le is the iron core stack length, do is the outer diameter of the stator 10, kd is the ratio of the inner diameter to the outer diameter of the stator 10, and p is the number of poles of the motor.

However, for the back-wound permanent magnet machine of the present invention, it is also assumed that the coil winding 20 is in the form of a racetrack, and therefore the actual length of the winding in one stator slot can be expressed as:

where Le is the core stack length, do is the outer diameter of the stator 10, and Di is the inner diameter of the stator 10.

Through comparative analysis, it can be known that, after L2< L1 simplification, the back-wound winding of the present invention is superior to the conventional motor winding structure under the constraint of the flat space of the stator 10 stack length Le, and the constraint condition of the flat space is as follows:

In addition, it is worth mentioning that the coil of the existing high-speed back-wound motor winding structure is embedded in the stator slot, the coil is wound on the stator core, and when the number of turns of the coil is large, the existing whole stator structure winding process is relatively complex, and the production and assembly are inconvenient. In contrast, the present invention can provide more stator slots in the same volume by setting the number of the inner slots 10a and the outer slots 10b to N = N × m × p, so that the overall structure of the motor is relatively compact.

Referring to fig. 2 to 4, in some embodiments, the stator core may include a plurality of core modules 110, and two adjacent core modules 110 are connected by a mortise and tenon structure. So, make the overall structure of motor compacter, be favorable to the motor miniaturization, also conveniently carry out the unitization concatenation simultaneously, further promoted the convenience of equipment.

It should be noted that the core module 110 and the m-phase coil winding 20 wound thereon form a stator module unit of the motor, which can be independently excited by applying current.

In order to further improve the compactness of the overall structure of the motor and improve the convenience of assembly, in an embodiment, referring to fig. 3, the number of the core modules 110 is equal to the number of poles of the motor, or the number of the core modules 110 is half of the number of poles of the motor.

As shown in fig. 3, in the present embodiment, the number of the first stator teeth 12, the second stator teeth 13, and the stator yoke 11 on each iron core module 110 may be n × m; or the number of the first stator teeth 12, the second stator teeth 13, and the stator yoke 11 on each core module 110 may be 2 × n × m. Therefore, the size of the motor structure can be reduced while the power density of the motor is improved, and the iron core modules 110 can be conveniently spliced.

Of course, in another embodiment, referring to fig. 4, the stator core may be formed by sequentially splicing and enclosing a plurality of stator tooth portions and stator yoke portions through a tenon-and-mortise structure, wherein the stator tooth portion includes a first stator tooth 12 and a second stator tooth 13 integrally formed with the first stator tooth 12, and the stator yoke portion is a portion connecting two adjacent stator tooth portions. In this way, the convenience of installation of the coil winding 20 can be improved.

Referring to fig. 2, in an embodiment, the first stator teeth 12, the second stator teeth 13, and the stator yoke 11 may be made of oriented silicon steel. Wherein, the orientation direction of the first stator tooth 12 and the second stator tooth 13 is the tooth height direction; the stator yoke 11 can be in a trapezoidal arrangement regardless of the mortise and tenon structure, and the orientation direction of the stator yoke is parallel to the upper bottom edge and the lower bottom edge of the stator yoke 11.

The invention fully utilizes the advantages of high saturation flux density and low loss of the oriented silicon steel in the orientation direction, ensures that the magnetic flux flowing direction of the stator teeth and the stator yoke is consistent with the orientation direction through the modularized structure and the arrangement of the orientation direction of the stator teeth and the stator yoke, and fully utilizes the advantages of the oriented silicon steel.

Referring to fig. 1, in an embodiment, the motor may further include a case 40 disposed around the stator 10, and a gap between the coil winding 20 and the case 40 and the stator core may be filled with a high thermal conductive potting material. Therefore, the efficiency of production and manufacturing can be improved, and the heat dissipation capacity of the motor can be improved.

In this embodiment, a plurality of cooling channels 40a may be formed in the casing 40, and cooling media such as water may be introduced into the cooling channels 40a to further enhance the heat dissipation effect.

It can be understood that the motor of the invention reduces the length of the non-effective part of the flat space winding, and meanwhile, the winding can be directly cooled by the cold liquid medium in the cooling channel 40a, thereby effectively improving the heat dissipation capability of the motor winding and improving the performance of the motor.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An electric machine, comprising:

2. The motor of claim 1, wherein a stator core lamination length of the motor is defined as Le, which satisfies the relationship:

3. The electric machine of claim 1 wherein said stator core comprises a plurality of core modules, adjacent ones of said core modules being connected by a mortise and tenon joint arrangement.

4. The electric machine of claim 3 wherein the number of core modules is equal to the number of poles of the electric machine; or

5. The electric machine of claim 4 wherein the number of said first stator teeth, said second stator teeth and said stator yoke on each said core module is n x m; or

6. The electric machine of claim 5, wherein the first stator teeth, the second stator teeth, and the stator yoke are of oriented silicon steel; the orientation direction of the first stator tooth and the second stator tooth is the tooth height direction; the stator yoke part is in a trapezoidal arrangement, and the orientation direction of the stator yoke part is parallel to the upper bottom edge and the lower bottom edge of the stator yoke part.

7. The motor of claim 1, wherein the rotor comprises a rotor core and magnetic steel, and the magnetic steel is attached to the rotor core; or

The magnetic steel is at least partially embedded in the rotor core.

8. The motor of claim 7, further comprising a rotating shaft, wherein the rotor is sleeved on the rotating shaft.

9. The motor of claim 1 further comprising a housing disposed over said stator, gaps between said coil windings and said housing and said stator core being filled with a thermally conductive potting material.

10. The electric machine of claim 1 wherein the cross-sectional area of the inner slot is equal to the cross-sectional area of the outer slot.