CN115051488A

CN115051488A - Strong magnetism-gathering type magnetic flux switching motor

Info

Publication number: CN115051488A
Application number: CN202210458874.6A
Authority: CN
Inventors: 周士贵; 马飞鸿; 张顺杰
Original assignee: Qufu Normal University
Current assignee: Qufu Normal University
Priority date: 2022-04-27
Filing date: 2022-04-27
Publication date: 2022-09-13

Abstract

A strong magnetism-gathering type magnetic flux switching motor comprises a stator and a rotor, wherein the stator is coaxially sleeved inside or outside the rotor, one side of the stator, which is close to the rotor, and one side of the rotor, which is close to the stator, are respectively provided with a stator tooth and a rotor tooth, the stator tooth is provided with a coil winding, a stator slot is formed between adjacent stator teeth, two permanent magnets which are magnetized in a tangential direction and a magnetic conduction block are arranged at the notch of the stator slot, the two permanent magnets are respectively arranged at two sides of the notch of the stator slot, the magnetic conduction block is arranged between the two permanent magnets, the magnetizing directions of the two adjacent permanent magnets are opposite, and the rotor is not provided with a winding or a permanent magnet.

Description

Strong magnetism-gathering type magnetic flux switching motor

Technical Field

The invention relates to the technical field of motors, in particular to a strong magnetism gathering type magnetic flux switching motor.

Background

The electric motor is a critical component of the overall drive system, which is related to the complexity of the system control strategy, the efficiency of the system, and the economics of the system. The permanent magnet motor has the advantages of high power density and high efficiency by virtue of the characteristic of high magnetic energy product of the permanent magnet, the winding of the switched reluctance motor is arranged on the stator, and the rotor has no permanent magnet or winding, so that the permanent magnet motor has the advantages of simple structure and high reliability. The permanent magnet is placed on the stator side of the switched reluctance motor to obtain the flux switching motor, the advantages of the permanent magnet motor and the switched reluctance motor are achieved, the structure is simple and reliable, the power density is high, heat dissipation and cooling are easy, and the switched reluctance motor is suitable for high-speed operation. The method has good application prospect in the fields of electric vehicles, multi-electric/full-electric airplanes, aviation generators, wind driven generators and the like.

The existing flux switching motor has low utilization rate of permanent magnets and high manufacturing cost, for example, patent document CN201320255345.2 discloses a six-phase flux switching type permanent magnet motor, patent document CN201120255319.0 discloses a low wind resistance flux switching motor, and patent document CN201410326088.6 discloses a multiple symmetrical winding flux switching motor, the permanent magnets in the flux switching motor disclosed by the above patent documents are all based on the flux switching motor proposed by e.hoang in france in 1997, the stator of the flux switching motor is composed of a plurality of units, each unit comprises a U-shaped iron core and a tangentially magnetized permanent magnet, the magnetization directions of the permanent magnets in adjacent units are opposite, the mounting structure of the spoke type of permanent magnet mounted in the stator iron core makes the permanent magnet usage large, the permanent magnet utilization rate is inevitably low, the manufacturing cost is increased, and the problem of magnetic leakage at the radial end is serious, it is disadvantageous for the wide application of the flux switching motor.

Disclosure of Invention

In order to solve the problems of low permanent magnet utilization rate and high motor manufacturing cost of the conventional magnetic flux switching motor, the invention provides a strong magnetism-gathering type magnetic flux switching motor, so that the application range of the motor is widened to a greater extent.

The technical scheme of the invention is as follows:

a strong magnetism gathering type magnetic flux switching motor comprises a stator and a rotor which are coaxially sleeved, wherein an air gap exists between the stator and the rotor, and the axial lengths of the stator and the rotor are equal.

The strongly-magnetism-gathering flux switching motor is characterized in that a plurality of stator teeth are distributed on the surface of one side, close to the rotor, of the stator, the stator teeth are distributed along the axial direction of the stator, the inner ends of the stator teeth are connected into a whole through a stator yoke, the outer ends of the stator teeth are distributed towards the rotor, the tooth widths of the stator teeth are equal, coil windings are arranged on the stator teeth, a stator slot is formed between every two adjacent stator teeth, the specifications of the stator slots are equal, two permanent magnets and one magnetic conduction block are arranged at the slot opening of each stator slot, the two permanent magnets are respectively attached to two sides of the magnetic conduction block, the outer sides of the two permanent magnets are respectively attached to the stator teeth, namely the arrangement mode of the magnetic conduction block and the permanent magnets in the stator slot is 'stator tooth-permanent magnet-magnetic conduction block-permanent magnet-stator tooth', the permanent magnets are magnetized in a tangential direction, the magnetizing directions of the adjacent permanent magnets are opposite, the adjacent coil windings belong to different phase windings, the widths of the permanent magnets are the same, the width of the magnetic conduction block is the same as the tooth width of the stator tooth, and the permanent magnets, the magnetic conduction block and the outer end of the stator tooth are enclosed into a closed ring shape.

Furthermore, a plurality of rotor teeth are uniformly distributed on the surface of one side of the rotor close to the stator, the rotor teeth are distributed along the axial direction of the rotor, the inner ends of the rotor teeth are connected into a whole through a rotor yoke, the outer ends of the rotor teeth are distributed in a way of pointing to the stator, the tooth widths of the rotor teeth are equal, it needs to be explained that the rotor is not provided with a winding or a permanent magnet, the tooth width of the rotor teeth is larger than the tooth width of the stator teeth and smaller than the sum of the tooth width of the stator teeth and the width of the permanent magnet, the magnetic flux is always closed through a path with the minimum magnetic resistance according to the 'minimum magnetic resistance principle', one rotor tooth of the motor rotates along the direction opposite to the permanent magnet-opposite to the stator teeth-opposite to the permanent magnet-opposite to the magnetic conducting block along the strong magnetism gathering magnetic flux switching motor, and the change rule of the permanent magnetic flux in the coil winding on the corresponding stator teeth is as follows: the rule of zero permanent magnetic flux, reverse maximum permanent magnetic flux, zero permanent magnetic flux and forward maximum permanent magnetic flux is that the magnetic flux switching process from the magnetic flux reversal maximum to the magnetic flux forward maximum is completed, along with the continuous rotation of the rotor, the magnetic flux in the coil winding can periodically change between the positive maximum value and the negative maximum value, so that sinusoidal back electromotive force with amplitude and phase changing along with the rotation of the rotor can be generated at two ends of the coil winding, and when sinusoidal current with the same phase as the induced electromotive force is introduced into each phase of the coil winding, electromagnetic torque can be generated.

According to the strong magnetism gathering type magnetic flux switching motor, the rotor is sleeved on the outer side of the stator or the rotor is sleeved on the inner side of the stator, so that an inner rotor motor or an outer rotor motor is formed.

Furthermore, the number X of the stator teeth is 4S, the number Y of the rotor teeth is X ± 2m, where m is a positive integer, S is the number of motor phases, and preferably, m is 1, which is most suitable, so as to ensure symmetry of the rotor, avoid the influence of unilateral magnetic tension on the motor, and reduce the amplitude of the cogging torque.

Furthermore, the coil windings are alternating current windings, and four coil windings which are symmetrically distributed around the circle center of the stator are connected in series to form a one-phase armature winding.

Further, the magnetic conduction block material includes the silicon steel sheet, the permanent magnet material includes neodymium iron boron, samarium cobalt or ferrite, of course, the permanent magnet material also can be other hard magnetic material, does not do any restriction here, the magnetic conduction block width is not less than the width of permanent magnet, sets up like this and makes the back electromotive force sine degree of motor highest, and the harmonic content is minimum, therefore the operation is the most steady.

Furthermore, the coil winding is a fractional slot concentrated winding, and is only wound on a single stator tooth, so that the using amount of copper wires used as the coil winding is less, and the coil winding has the advantages of lower copper loss and higher efficiency.

Furthermore, the tooth height of the stator teeth accounts for 3/10-1/2 of the outer diameter of the magnetic flux switching motor, the tooth height of the rotor teeth accounts for 3/25-1/5 of the outer diameter of the magnetic flux switching motor, and the stator teeth and/or the rotor teeth are formed by laminating silicon steel sheets or are of solid structures.

The invention has the beneficial effects that:

(1): compared with the traditional flux switching motor, the strong magnetism gathering type flux switching motor mainly changes the placement position of the permanent magnet in the stator and the shape of the permanent magnet, has small change on the processing technology of the stator and the rotor core, and has better compatibility with the productivity of the existing motor;

(2): according to the mounting structure of the permanent magnet-the magnetic conduction block-the permanent magnet of the strong magnetism gathering type magnetic flux switching motor, when the rotor rotates to the state that the rotor pole is opposite to the magnetic conduction block, the magnetic flux in the corresponding coil winding is provided by the corresponding stator teeth in parallel connection with the permanent magnets on two sides in the anticlockwise direction in the clockwise direction, and the two magnetic conduction blocks attached to the two permanent magnets both play a role of providing a permanent magnet magnetic flux path for the permanent magnets, so that the permanent magnet has a stronger magnetism gathering effect compared with the traditional magnetic flux switching motor, a larger air gap magnetic density is obtained under the condition of less permanent magnet consumption, and the utilization rate of the permanent magnets, the torque density and the power density are greatly improved;

(3): compared with the conventional magnetic flux switching motor, the strong magnetism gathering type magnetic flux switching motor provided by the invention has the advantages that the space required by the permanent magnet is greatly reduced, the area of the stator slot of the motor is increased, and the electric load capacity is greatly improved;

(4): the strong magnetism-gathering type flux switching motor provided by the invention meets the principles of 'winding consistency' and 'winding complementarity', higher harmonics of permanent magnet flux linkages of two sets of coil windings in the same-phase armature winding can be mutually offset, the sine of the permanent magnet flux linkages and counter electromotive force is improved, and the harmonic content is reduced.

Drawings

The aspects and advantages of the present application will become apparent to those ordinarily skilled in the art upon review of the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.

In the drawings:

fig. 1 is a schematic view of an internal structure of a flux switching motor in an embodiment;

FIG. 2 is a schematic diagram of connection of coil windings in the embodiment;

FIG. 3 is a schematic view showing an expanded structure of a stator in the embodiment;

FIG. 4 is a schematic diagram of magnetic fluxes in an A-phase armature winding of the flux switching motor in the embodiment (wherein the left diagram is a maximum reverse magnetic flux position of the A-phase armature winding permanent magnet, and the right diagram is a maximum forward magnetic flux position of the A-phase armature winding);

fig. 5 is a schematic view of an internal structure of a conventional flux switching motor provided in the embodiment;

FIG. 6 is a comparison graph of back emf of a flux switching motor of a strong flux focusing type in an embodiment with a conventional flux switching motor;

FIG. 7 is a graph comparing electromagnetic torques of a flux switching motor of a strong flux focusing type in the embodiment and a conventional flux switching motor;

FIG. 8 is a graph comparing output power of a flux switching motor of a strong flux focusing type with that of a conventional flux switching motor in the embodiment;

the components represented by the reference numerals in the figures are:

1. a first stator; 11. a stator shaft; 12. a stator yoke; 13. stator teeth; 14. a coil winding; 15. a permanent magnet; 16. a magnetic conduction block; 2. a first rotor; 21. rotor teeth; 1', a second stator; 2' and a second rotor.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. It should be noted that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art, and that the present disclosure may be implemented in various forms, and should not be limited by the embodiments set forth herein.

Examples

The embodiment provides a strong magnetic flux concentration type flux switching motor, referring to fig. 1, including a first stator 1 and a first rotor 2 coaxially sleeved, where the first rotor 2 is sleeved outside the first stator 1 to form an outer rotor motor, and the axial lengths of the first rotor 2 and the first stator 1 are the same, of course, the first stator 1 may also be coaxially sleeved outside the first rotor 2 to form an inner rotor motor, which is not limited in this embodiment.

In this embodiment, the first stator 1 includes a stator shaft 11 located in the middle, a plurality of stator teeth 13 are uniformly distributed on the outer side of the stator shaft 11, the stator teeth 13 include a plate-shaped structure, the inner sides of the stator teeth are connected into a whole through a stator yoke 12 and then connected with the stator shaft 11, the outer side of the stator teeth points to the outer side of the stator shaft 11, the plane where the plate-shaped stator teeth 13 are located is arranged through the axis of the stator shaft 11, and the length of the stator teeth 13 is the same as the axial length of the stator shaft 11.

Further, in this embodiment, the magnetic flux switching motor is a three-phase motor, the number of teeth of the stator teeth 13 is 12, and certainly, the number of teeth of the stator teeth 13 satisfies four times of the number of phases of the magnetic flux switching motor, this embodiment only takes the three-phase motor as an example, no limitation is imposed on the specific number of the stator teeth 13, and the widths of the stator teeth 13 are equal and are 1/48 of the outer perimeter of the first stator 1.

Furthermore, coil windings 14 are also arranged on the stator teeth 13, the number of the coil windings 14 is equal to that of the stator teeth 13, and the coil winding 14 is a fractional slot concentrated winding, i.e. the coil winding 14 is only wound on a single stator tooth 13, so the design makes the copper wire usage of the coil winding 14 less, therefore, the stator has the advantages of lower copper loss and higher efficiency, and in combination with the figure 2, four groups of coil windings 14 which are symmetrically distributed on the axle center of the first stator 1 are connected in series to form a one-phase armature winding, namely, the A1 pole coil winding, the A2 pole coil winding, the A3 pole coil winding and the A4 pole coil winding are connected in series to form an A-phase armature winding, the B1 pole coil winding, the B2 pole coil winding, the B3 pole coil winding and the B4 pole coil winding are connected in series to form a B-phase armature winding, and the C1 pole coil winding, the C2 pole coil winding, the C3 pole coil winding and the C4 pole coil winding are connected in series to form a C-phase armature winding.

In this embodiment, first rotor 2 includes a plurality of rotor teeth 21 of inside equipartition, rotor teeth 21 includes the lath structure, and its one side is connected as a whole through the rotor yoke, and the axis arrangement of the directional stator shaft 11 of opposite side, just not set up coil winding 14 on the rotor teeth 21, stator teeth 13 and rotor teeth 21 are magnetic material and constitute, for example are laminated by the silicon steel sheet and become or be solid structure, a plurality of the tooth width of rotor teeth 21 equals, and is 19/700 of first rotor 2 internal perimeter.

Further, the number of the rotor teeth 21 is equal to the number of the stator teeth 13 ± 2m, where m is a positive integer, preferably, m is 1, and is most suitable, that is, the number of the rotor teeth 21 is 14, so that the symmetry of the first rotor 2 can be ensured, the motor is prevented from being influenced by unilateral magnetic tension, and the amplitude of the cogging torque is reduced.

As a main concept of the present embodiment, a stator slot is formed between two adjacent stator teeth 13, two permanent magnets 15 and a magnetic conduction block 16 are respectively disposed at the notch of each stator slot, the two permanent magnets 15 are respectively attached to two sides of the magnetic conduction block 16, and the outer sides of the two permanent magnets 15 are respectively attached to the stator teeth 13, that is, the arrangement mode of the magnetic blocks 16 and the permanent magnets 15 in the stator slots is 'stator teeth 13-permanent magnets 15-magnetic blocks 16-permanent magnets 15-stator teeth 13', the permanent magnets 15 are magnetized tangentially, the magnetizing directions of the adjacent permanent magnets 15 are opposite, the current directions in the adjacent coil windings 14 are opposite, the widths of the permanent magnets 15 are the same, the width of the magnetic conduction block 16 is the same as the tooth width of the stator tooth 13, and the permanent magnets 15, the magnetic conduction block 16 and the outer end of the stator tooth 13 form a closed ring together.

Further, permanent magnet 15 and magnetic conduction piece 16 are the bar structure, and its direction of arranging along stator tooth 13 arranges, and length is the same with stator tooth 13 length, the 16 materials of magnetic conduction piece are the silicon steel sheet, the 15 materials of permanent magnet are the neodymium iron boron, of course, the 15 materials of permanent magnet also can be other hard magnetic material, for example samarium cobalt or ferrite, and this embodiment does not do any restriction.

It should be noted that, with reference to fig. 3, in the magnetic flux switching motor described in this embodiment, the magnetization directions of the permanent magnets 15 all point to the magnetic conductive block 16, that is, the magnetization direction of the permanent magnet 15 located on the clockwise side of the stator tooth 13 is a clockwise direction, and the magnetization direction of the permanent magnet 15 located on the counterclockwise side of the stator tooth 13 is a counterclockwise direction, and certainly, as long as it is ensured that the magnetization directions of two adjacent permanent magnets 15 are opposite, it may also be set that the magnetization direction of the permanent magnet 15 located on the clockwise side of the stator tooth 13 is a counterclockwise direction, and the magnetization direction of the permanent magnet 15 located on the counterclockwise side of the stator tooth 13 is a clockwise direction, which is not particularly limited in this embodiment.

It should be noted that, with reference to fig. 4, the tooth width of the rotor tooth 21 is greater than the tooth width of the stator tooth 13 and smaller than the sum of the tooth width of the stator tooth 13 and the outer end width of the permanent magnet 15, according to the "minimum reluctance principle", the magnetic flux always closes through the path with the minimum reluctance, and as the strongly focused flux switching motor rotates along the direction opposite to the permanent magnet 15-opposite to the stator tooth 13-opposite to the permanent magnet 15-opposite to the flux guide block 16, the change rule of the permanent magnet flux in the coil winding 14 on the corresponding stator tooth 13 is as follows: the rule of zero permanent magnetic flux-maximum reverse permanent magnetic flux-zero permanent magnetic flux-maximum forward permanent magnetic flux is that a magnetic flux switching process from maximum magnetic flux reversal to maximum magnetic flux forward is completed, and with continuous rotation of the first rotor 2, magnetic flux in the coil winding 14 changes periodically between maximum positive and negative values, so that sinusoidal back electromotive force with amplitude and phase changing along with rotation of the first rotor 2 is generated at two ends of the coil winding 14, and when sinusoidal current with the same phase as induced electromotive force is introduced into the coil winding 14 of each phase, electromagnetic torque is generated.

Preferably, the width of the magnetic conduction block 16 is not less than that of the permanent magnet 15, so that the back electromotive force of the motor is highest in sine degree, the harmonic content is lowest, and the operation is most stable.

In the present embodiment, the tooth height of the stator teeth 13 is 2/5 of the outer diameter of the flux switching motor, and the tooth height of the rotor teeth 21 is 4/25 of the outer diameter of the flux switching motor.

In this embodiment, in combination with fig. 5, in order to better embody the advantages of the magnetic flux switching motor in this embodiment, a conventional magnetic flux switching motor is used as a comparison, the conventional magnetic flux switching motor includes a second stator 1 ' and a second rotor 2 ', the second stator 1 ' and the second rotor 2 ' are coaxially installed, the second stator 1 ' includes second stator teeth, second coil windings are wound on the second stator teeth, second permanent magnets are arranged on the second stator teeth, the second permanent magnets are wholly vertically inserted into the middle of the second stator teeth, the second permanent magnets are tangentially magnetized, and the magnetizing directions of the two adjacent second permanent magnets are opposite.

Further, for the fair comparison of the performances of the flux switching motor described in this embodiment and the conventional flux switching motor, it is ensured that the number of rotor teeth 21 of the flux switching motor of this embodiment is 14, the conventional flux switching motor includes a second rotor tooth, and the number of second rotor teeth is 14, the number of stator teeth 13 of the flux switching motor of this embodiment is 12, the number of second stator teeth of the conventional flux switching motor is 12, and the two motors have the same motor rotation speed, the rotor inner diameter and outer diameter, the stator inner diameter and outer diameter, the core lamination length, the air gap thickness, and the current density, so as to compare the three key performances of the no-load back electromotive force, the electromagnetic torque, and the output power.

Further, in conjunction with fig. 6, the back electromotive force of the flux switching motor of the present embodiment is 27% higher than that of the conventional flux switching motor; with reference to fig. 7, the electromagnetic torque of the flux switching motor of the present embodiment is 17% higher than that of the conventional flux switching motor; referring to fig. 8, the flux switching motor according to the present embodiment has an output power 16.7% higher than that of the conventional flux switching motor. Therefore, as can be seen from fig. 6 to 8, the flux switching motor according to the present embodiment has better performance than the conventional flux switching motor in the case of using less permanent magnets 15 and having a lower manufacturing cost.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or additions or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A strong magnetism gathering type magnetic flux switching motor comprises a stator and a rotor which are coaxially sleeved, and is characterized in that an air gap exists between the stator and the rotor, and the axial lengths of the stator and the rotor are equal;

the stator is provided with a plurality of stator teeth (13) on the surface close to one side of the rotor, the stator teeth (13) are arranged along the circumferential direction of the stator, the inner ends of the plurality of stator teeth (13) are connected into a whole through a stator yoke (12), the outer ends of the stator teeth are arranged in a way of pointing to the rotor, the tooth widths of the plurality of stator teeth (13) are equal, the stator teeth (13) are provided with coil windings (14), a stator slot is formed between every two adjacent stator teeth (13), the slot opening of each stator slot is provided with two permanent magnets (15) and one magnetic conduction block (16), the two permanent magnets (15) are respectively attached to two sides of the magnetic conduction block (16), the outer sides of the two permanent magnets (15) are respectively attached to the stator teeth (13), the permanent magnets (15) are magnetized in a tangential direction, the magnetizing directions of the adjacent permanent magnets (15) are opposite, and the adjacent coil windings (14) belong to different phase windings, the widths of the permanent magnets (15) are the same, and the width of the magnetic conduction block (16) is the same as the tooth width of the stator tooth (13);

a plurality of rotor teeth (21) are uniformly distributed on the surface of one side of the rotor, which is close to the stator, the inner ends of the plurality of rotor teeth (21) are connected into a whole through a rotor yoke, the outer ends of the plurality of rotor teeth are arranged in a way of pointing to the stator, and the tooth widths of the plurality of rotor teeth (21) are equal;

the rotor is not provided with a winding or a permanent magnet (15), and the tooth width of the rotor teeth (21) is larger than that of the stator teeth (13) and smaller than the sum of the tooth width of the stator teeth (13) and the width of the permanent magnet (15).

2. The flux switching motor of claim 1, wherein the rotor is fitted to an outer side of the stator or the rotor is fitted to an inner side of the stator.

3. A flux switching machine according to claim 2, wherein the number X of stator teeth (13) is 4S, the number Y of rotor teeth (21) is X ± 2m, where m is a positive integer and S is the number of machine phases.

4. A strongly-concentrated flux-switching electric machine according to claim 3, wherein said coil windings (14) are ac windings, and four coil windings (14) symmetrically distributed around the center of the stator are connected in series to form a single-phase armature winding.

5. A strongly concentrated flux switching machine according to claim 4, characterized in that said flux-conducting blocks (16) comprise silicon steel sheets.

6. A flux switching machine of the flux focusing type according to claim 1, characterized in that said coil winding (14) is a fractional-slot concentrated winding.

7. A flux switching machine of the flux focusing type according to claim 1, characterized in that said permanent magnet (15) comprises a hard magnetic material.

8. A flux switching machine of the flux type according to claim 1, characterized in that the teeth of the stator teeth (13) have a height of 3/10-1/2 of the outer diameter of the flux switching machine and the teeth of the rotor teeth (21) have a height of 3/25-1/5 of the outer diameter of the flux switching machine.