WO2024078113A1

WO2024078113A1 - Permanent magnet-assisted synchronous reluctance motor and compressor

Info

Publication number: WO2024078113A1
Application number: PCT/CN2023/112881
Authority: WO
Inventors: 邱小华; 杨向宇; 朱晓光; 李宏涛
Original assignee: 广东美芝制冷设备有限公司; 华南理工大学
Priority date: 2022-10-14
Filing date: 2023-08-14
Publication date: 2024-04-18
Also published as: CN116191725A

Abstract

A permanent magnet-assisted synchronous reluctance motor and a compressor. The permanent magnet-assisted synchronous reluctance motor comprises a rotor and a stator; the rotor comprises a rotor core, a plurality of cranked slots, a plurality of permanent magnets, and a plurality of magnetic barrier groups; a first quadrature-axis magnetic conduction channel is formed between a layer of magnetic barrier holes close to a cranked slot and the cranked slot; and one end of the first quadrature-axis magnetic conduction channel has a different width from the other end.

Description

Permanent magnet assisted synchronous reluctance motor and compressor

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with application number: 202211270422.1 and application date of October 14, 2022, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference.

Technical Field

The present application relates to the technical field of compressors, and in particular to a permanent magnet assisted synchronous reluctance motor and a compressor.

Background technique

The synchronous reluctance motor has multiple layers of rotor magnetic barriers and works by relying on the reluctance torque generated by the asymmetric rotor magnetic circuit. This type of motor has the advantages of low cost, simple manufacturing, and low rotor loss, but has the disadvantages of low power factor and torque density and large torque pulsation. In order to improve the torque and power factor of this type of motor, a certain amount of low-performance permanent magnets (ferrite or bonded NdFeB) can be inserted into the rotor magnetic barriers to assist in excitation, thereby reducing the excitation component of the motor current and generating permanent magnet torque. This is the permanent magnet assisted synchronous reluctance motor.

As a combination of permanent magnet synchronous motor and synchronous reluctance motor, permanent magnet assisted synchronous reluctance motor makes maximum use of the reluctance torque of synchronous reluctance motor and uses permanent magnet torque for assistance, combining the advantages of both motors. Its permanent magnet assisted synchronous reluctance motor has high efficiency and power factor, and therefore is receiving more and more attention.

In the related technology, when the motor rotor rotates, the front side of the cross-axis magnetic channel formed between the curved groove for installing the permanent magnet and a layer of magnetic barrier holes close to the curved groove, that is, the front side in the same direction as the rotation direction of the motor rotor, has a large electromagnetic force and is easily saturated. Oversaturation will reduce the performance of the motor. At the same time, the torque pulsation of the motor is also large, which makes the motor noise also larger.

Summary of the invention

The main purpose of this application is to propose a permanent magnet assisted synchronous reluctance motor, aiming to improve the magnetic circuit in the cross-axis magnetic conduction channel and improve the motor performance.

To achieve the above-mentioned purpose, the present application proposes a permanent magnet assisted synchronous reluctance motor, which includes a rotor and a stator sleeved on the outside of the rotor, the stator includes a stator core and windings wound on stator teeth, and the rotor includes a rotor core, a plurality of curved grooves, a plurality of permanent magnets and a plurality of magnetic barrier groups; the plurality of curved grooves are arranged in the rotor core and are arranged at intervals along the circumference of the rotor core, and the two ends of the curved grooves extend toward the edge of the rotor core; the plurality of permanent magnets are arranged in the plurality of curved grooves; the plurality of magnetic barrier groups are arranged in the plurality of curved grooves away from the center of the rotor core. On one side, the magnetic barrier group includes at least one layer of magnetic barrier holes arranged at intervals along the d-axis direction of the rotor, the number of magnetic barrier holes in one layer is set to multiple, and the multiple magnetic barrier holes are arranged at intervals along the extension direction of the slot wall of the curved slot; a first cross-axis magnetic conductive channel is formed between a layer of magnetic barrier holes close to the curved slot and the curved slot, the first cross-axis magnetic conductive channel has a first end and a second end arranged oppositely, and the width of the first end is not greater than the width of the second end; wherein the rotation direction of the rotor core is a first direction, the direction from the first end to the second end is a second direction, and the first direction is opposite to the second direction.

In one embodiment, the curved groove group includes a first curved groove and a second curved groove, the first curved groove is located between the second curved groove and the center of the rotor core, and in a cross section perpendicular to the axial direction of the rotor, the cross-sectional area of the first curved groove is greater than the cross-sectional area of the second curved groove.

In one embodiment, in a cross section perpendicular to the axial direction of the rotor, a thickness of a middle portion of the permanent magnet is greater than a thickness of both ends of the permanent magnet.

In one embodiment, there is a gap between two ends of the permanent magnet and two ends of the curved groove in which the permanent magnet is embedded.

In one embodiment, the gap is used to be filled with a non-magnetic conductive medium.

In one embodiment, the thickness of the rotor along the axial direction is not less than the thickness of the stator along the axial direction.

In one embodiment, the curved groove is arranged in a U shape.

In one embodiment, the curved groove is arranged in a V-shape.

In one embodiment, the curved groove is arranged in an arc shape.

The present application also proposes a compressor, which includes the permanent magnet assisted synchronous reluctance motor. The permanent magnet assisted synchronous reluctance motor includes a rotor and a stator sleeved on the outside of the rotor, the stator includes a stator core and a winding wound on the stator teeth, and the rotor includes a rotor core, a plurality of curved grooves, a plurality of permanent magnets and a plurality of magnetic barrier groups; the plurality of curved grooves are arranged in the rotor core and are arranged at intervals along the circumference of the rotor core, and the two ends of the curved grooves extend toward the edge of the rotor core; the plurality of permanent magnets are arranged in the plurality of curved grooves; the plurality of magnetic barrier groups are arranged on the side of the plurality of curved grooves away from the center of the rotor core, and the magnetic barrier group includes a plurality of permanent magnets arranged along the plurality of curved grooves. At least one layer of magnetic barrier holes is arranged at intervals in the d-axis direction of the rotor, the number of magnetic barrier holes in one layer is set to be multiple, and the multiple magnetic barrier holes are arranged at intervals along the extension direction of the slot wall of the curved slot; a first cross-axis magnetic conductive channel is formed between a layer of magnetic barrier holes close to the curved slot and the curved slot, the first cross-axis magnetic conductive channel has a first end and a second end that are arranged oppositely, and the width of the first end is not greater than the width of the second end; wherein the rotation direction of the rotor core is a first direction, the direction from the first end to the second end is a second direction, and the first direction is opposite to the second direction.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

FIG1 is a schematic structural diagram of a rotor of a permanent magnet assisted synchronous reluctance motor according to an embodiment of the present invention;

FIG2 is an enlarged view of point A in FIG1 ;

FIG3 is a schematic structural diagram of a rotor of a permanent magnet assisted synchronous reluctance motor according to an embodiment of the present invention;

FIG4 is a schematic structural diagram of another embodiment of a rotor of a permanent magnet assisted synchronous reluctance motor of the present application;

FIG5 is a comparison diagram of the main electromagnetic forces of the permanent magnet assisted synchronous reluctance motor of the present application and the ordinary permanent magnet assisted synchronous reluctance motor;

FIG6 is a torque pulsation comparison diagram of the permanent magnet assisted synchronous reluctance motor of the present application and a common permanent magnet assisted synchronous reluctance motor.

Description of Figure Numbers:

The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Detailed ways

The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and/or" appearing in the full text is to include three parallel schemes, taking "A and/or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

The present application proposes an embodiment of a permanent magnet assisted synchronous reluctance motor, which can be used in air-conditioning compressors, electric vehicles and fan systems. The synchronous reluctance motor has multiple layers of rotor magnetic barriers and works by relying on the reluctance torque generated by the asymmetry of the rotor magnetic circuit. This motor has the advantages of low cost, simple manufacturing and low rotor loss, but has the disadvantages of low power factor and torque density and large torque pulsation. In order to improve the torque and power factor of this type of motor, a certain low-performance permanent magnet (ferrite or bonded NdFeB) can be inserted into the rotor magnetic barrier to assist in excitation, so as to reduce the excitation component of the motor current and generate permanent magnet torque. This is the permanent magnet assisted synchronous reluctance motor.

When designing permanent magnets in magnetic barriers, it is necessary to consider the effect of permanent magnet flux on the degree of magnetic circuit saturation. A large permanent magnet flux is likely to cause magnetic circuit saturation and reduce the rotor salient pole ratio; while a small permanent magnet flux has little effect on the improvement of torque and power factor. Although low-performance permanent magnets have low coercive force, their demagnetization curve has good linearity.

The synthesis formula of reluctance torque and permanent magnet torque is as follows:

T＝mp*(Lq-Ld)*id*iq+mp*ψPM*iq. Among them,

T is the output torque of the motor. Increasing the value of T can improve the motor performance. The first term in the equation after T is the reluctance torque, and the second term is the permanent magnet torque. ΨPM is the maximum value of the stator-rotor coupling flux generated by the permanent magnet of the motor, m is the number of phases of the stator conductor, Ld and Lq are the d-axis and q-axis inductances respectively, where the d-axis refers to the inductance of the rotor with respect to the main The axis with which the magnetic pole axis coincides, the q axis refers to the axis perpendicular to the main magnetic pole axis, where perpendicular refers to the electrical angle; id and iq are the components of the armature current in the d-axis and q-axis directions, respectively. According to the formula, increasing the inductance difference between Ld and Lq and ψpm can increase the output torque, that is, while ensuring that one of the reluctance torque and permanent magnet torque remains unchanged, increasing the other of the two can increase the total output torque of the motor, thereby improving the efficiency of the motor.

In the related art, the motor performance is mainly improved by improving the performance of permanent magnets, that is, by increasing the value of output torque by increasing the permanent magnet torque, thereby improving the motor efficiency. A common practice is to build in rare earth permanent magnets. However, since rare earths are non-renewable resources and are expensive, the wider application of this type of motor is limited. In addition, simply improving the performance of permanent magnets to improve motor performance cannot meet the urgent need to further improve motor efficiency. In addition, most current motors use a structure with two or more layers of permanent magnets, which results in high motor cost and weak anti-demagnetization ability. At the same time, a multi-layer permanent magnet structure is used, which affects the motor production rhythm and affects the performance of the motor rotor.

Please refer to Figures 1 to 4. In one embodiment of the present application, the permanent magnet assisted synchronous reluctance motor includes a rotor 10 and a stator sleeved on the outside of the rotor 10, the stator includes a stator core and windings wound on stator teeth, the rotor 10 includes a rotor core 100, a plurality of curved slots 200, a plurality of permanent magnets 300 and a plurality of magnetic barrier groups 400; the plurality of curved slots 200 are arranged in the rotor core 100 and are arranged at intervals along the circumference of the rotor core 100, and the two ends of the curved slots 200 extend toward the edge of the rotor core 100; the plurality of permanent magnets 300 are arranged in the plurality of curved slots 200; the plurality of magnetic barrier groups 400 are arranged on the side of the plurality of curved slots 200 away from the center of the rotor core 100, and the plurality of permanent magnets 300 are arranged on the side of the plurality of curved slots 200 away from the center of the rotor core 100. The magnetic barrier group 400 includes at least one layer of magnetic barrier holes 410 arranged at intervals along the axial direction of the rotor 10d, the number of the magnetic barrier holes 410 in one layer is set to be multiple, and the multiple magnetic barrier holes 410 are arranged at intervals along the extension direction of the slot wall of the curved slot 200; a first cross-axis magnetic conductive channel 510 is formed between a layer of the magnetic barrier holes 410 close to the curved slot 200 and the curved slot 200, the first cross-axis magnetic conductive channel 510 has a first end 511 and a second end 512 arranged oppositely, and the width of the first end 511 is not greater than the width of the second end 512; wherein the rotation direction of the rotor core 100 is a first direction, the direction from the first end 511 to the second end 512 is a second direction, and the first direction is opposite to the second direction.

Specifically, the rotor core 100 and the stator core are formed by laminating silicon steel sheets and have a certain stack height. The rotor core 100 is driven by the magnetic effect of the permanent magnet 300, and the motor rotor 10 can rotate relative to the motor stator to achieve normal operation of the motor. The rotor core 100 is formed by laminating high magnetic permeability materials or silicon steel punchings, and is formed by laminating high magnetic permeability materials or silicon steel punchings, has high magnetic flux rate, high structural strength, and is easy to process.

A plurality of curved grooves 200 are provided on the rotor core 100. The curved grooves 200 are arranged in a curved shape. The curved grooves 200 may have one curved portion or may have multiple curved portions, and there is no specific limitation on this. When the curved grooves 200 have multiple curved portions, their shape is generally arranged in a wave shape. The plurality of curved grooves 200 are arranged at intervals along the circumference of the rotor core 100, and are specifically evenly distributed along the circumference with the center of the rotor core 100 as the center of the circle. The two ends of the curved grooves 200 extend toward the edge of the rotor core 100, and form an area for the arrangement of the plurality of magnetic barrier groups 400 between the curved grooves 200 and the edge of the rotor core 100. The plurality of magnetic barrier groups 400 are arranged on the side of the plurality of curved grooves 200 away from the center of the rotor core 100. It should be noted that the curved groove 200 is mainly used to install the permanent magnet 300, and the permanent magnet 300 has a magnetic pole, so the number of the curved grooves 200 is set to an even number. As shown in Figure 1, 6 curved grooves 200 are arranged at intervals along the circumferential direction of the rotor core 100, and at least one permanent magnet 300 is placed in each curved groove 200. The polarities of the permanent magnets 300 in any two adjacent curved grooves 200 are opposite, and multiple permanent magnets 300 are distributed alternately according to N poles and S poles along the circumferential direction of the rotor core 100. In the present embodiment, the plurality of curved grooves 200 are arranged as a single-layer structure. Compared with the double-layer structure of the motor rotor 10 in the related art, the permanent magnets 300 are placed in the curved grooves 200 with a single-layer structure, so that the thickness of the permanent magnets 300 can be increased within a limited volume, thereby improving the anti-demagnetization ability of the permanent magnets 300 and improving the reliability of the motor; at the same time, the production efficiency of the motor rotor 10 with a single-layer curved groove 200 structure is also higher; at the same time, the number of permanent magnets 300 required to be placed in the curved grooves 200 with a single-layer structure is relatively reduced, and the overall usage of the permanent magnets 300 is reduced, so the production cost of the rotor 10 can be further reduced, thereby reducing the production cost of the motor.

The magnetic barrier group 400 includes at least one layer of magnetic barrier holes 410 arranged at intervals along the axial direction of the rotor 10d. The number of magnetic barrier holes 410 in one layer is set to be multiple. The multiple magnetic barrier holes 410 are arranged at intervals along the extension direction of the slot wall of the curved slot 200. The magnetic barrier holes 410 can be filled with air or other non-magnetic conductive materials. The slot wall of the curved slot 200 can be an inner slot wall close to the edge of the rotor core 100, or an outer slot wall close to the center of the rotor core 100. The extension directions of the inner slot wall and the outer slot wall can be the same or different. In this embodiment, the extension directions of the inner slot wall and the outer slot wall are substantially the same, so the multiple magnetic barrier holes 410 are arranged at intervals along the extension direction of the inner slot wall of the curved slot 200 or along the extension direction of the outer slot wall of the curved slot 200. A direct-axis magnetic channel 600 is formed between two adjacent magnetic barrier holes 410. The magnetic resistance in the d-axis direction where the direct-axis magnetic channel 600 is located is small, with high magnetic flux and large inductance Ld; and the magnetic resistance in the q-axis direction at the center line of the magnetic barrier hole 410 is very high, and the inductance Lq is small, which can increase the inductance difference between the d-axis and q-axis directions, thereby improving the torque output capacity of the motor. On the other hand, the magnetic barrier hole 410 is arranged between the inner slot wall of the curved slot 200 and the edge of the rotor core 100, which can reduce the impact on the permanent magnetic force, and at the same time regulate the path of the magnetic line of force, weaken the magnetic field harmonics in the air gap, and alleviate the degree of magnetic saturation. A magnetic barrier is formed during the rotation of the motor rotor 10 to improve the power density and torque density of the motor, improve the overload capacity of the motor, and effectively improve the torque pulsation of the motor. On the basis of reducing the amount of permanent magnets 300 used in the motor, that is, reducing the production cost, the motor performance is greatly improved, and the product competitiveness is improved.

A plurality of permanent magnets 300 are installed in a plurality of curved grooves 200. To ensure the performance of the motor rotor 10, the number of the permanent magnets 300 is set to be no less than the number of the curved grooves 200, and at least one permanent magnet 300 should be placed in each curved groove 200. The shape of the permanent magnet 300 is adapted to the shape of the curved groove 200, and the permanent magnet 300 has at least two oppositely disposed side edges that abut against the inner wall surface of the curved groove 200 to ensure the stability of the permanent magnet 300 after being installed in the curved groove 200. In terms of the selection of permanent magnet 300 materials, in order to increase the permanent magnet torque of the motor as much as possible, it is generally hoped to select relatively high-performance permanent magnets 300, and the amount of permanent magnets 300 used should fill the curved groove 200 as much as possible. However, in terms of the utilization of the reluctance torque, the higher the residual magnetic flux density of the permanent magnet 300 is, the better it is. As the residual magnetic flux density of the permanent magnet 300 increases, the motor rotor 10 will also be saturated, resulting in a decrease in inductance. Among them, the influence of the magnetic circuit saturation of the rotor 10 on the q-axis inductance is greater. In addition, through research, it is found that an appropriate amount of residual magnetic flux density of the permanent magnet 300 can cause a certain saturation in the gap between the two ends of the permanent magnet 300 and the two ends of the curved slot 200, which is very beneficial for reducing the d-axis inductance. Since the main output torque of the motor is the reluctance torque, especially when the motor enters the high-speed weak magnetic region, the proportion of the reluctance torque in the entire electromagnetic torque is further increased, so it is very necessary to select the appropriate permanent magnet 300 material properties to affect the difference between the d-axis inductance and the q-axis inductance.

Please refer to FIG. 1 to FIG. 6 . A first cross-axis magnetic conductive channel 510 is formed between a layer of magnetic barrier holes 410 near the curved slot 200 and the curved slot 200. The first cross-axis magnetic conductive channel 510 has a first end 511 and a second end 512 that are arranged opposite to each other. The rotation direction of the rotor core 100, that is, the rotor 10, is defined as the first direction. When the rotor 10 rotates, the electromagnetic force of the front side of the first cross-axis magnetic conductive channel 510, that is, the second end 512 of the first cross-axis magnetic conductive channel 510 is large and easy to saturate. Oversaturation will reduce the performance of the motor, and the torque pulsation is also large, so that the noise of the motor is large. Therefore, the width of the first end 511 of the first cross-axis magnetic conductive channel 510 is set to be no greater than the width of the second end 512. Regarding the determination of the positions of the first end 511 and the second end 512 of the first cross-axis magnetic conductive channel 510, the direction from the first end 511 to the second end 512 is defined as the second direction, and the rotation direction of the rotor core 100 is defined as the first direction. It is necessary to ensure that the first direction is opposite to the second direction. It should be noted that the first direction is the rotation direction of the rotor core 100 of the motor when the rotor 10 is working, and the second direction is the winding direction of the first cross-axis magnetic channel 510. Assuming that the first direction is clockwise, the second direction is counterclockwise, and vice versa. Such a setting can improve the magnetic circuit in the first cross-axis magnetic channel 510, make the magnetic field distribution more uniform, reduce the iron loss of the motor, thereby improving the performance of the motor, while reducing the electromagnetic force density of the motor and reducing the torque pulsation of the motor.

The permanent magnet assisted synchronous reluctance motor of the present application comprises a rotor 10 and a stator sleeved on the outside of the rotor 10, wherein the stator comprises a stator core and windings wound on stator teeth, and the rotor 10 comprises a rotor core 100, a plurality of curved slots 200, a plurality of permanent magnets 300 and a plurality of magnetic barrier groups 400; the plurality of curved slots 200 are arranged in the rotor core 100 and are arranged at intervals along the circumference of the rotor core 100, and the two ends of the curved slots 200 extend toward the edge of the rotor core 100; the plurality of permanent magnets 300 are arranged in the plurality of curved slots 200; the plurality of magnetic barrier groups 400 are arranged on a side of the plurality of curved slots 200 away from the center of the rotor core 100, and the magnetic barrier group 400 comprises a plurality of permanent magnets 300 arranged along the circumference of the rotor core 100; The rotor 100 has at least one layer of magnetic barrier holes 410 arranged in a spaced-apart manner in the axial direction, and the number of the magnetic barrier holes 410 in one layer is set to be multiple, and the multiple magnetic barrier holes 410 are spaced-apart in the extending direction of the slot wall of the curved slot 200; a first cross-axis magnetic conductive channel 510 is formed between the magnetic barrier holes 410 in a layer close to the curved slot 200 and the curved slot 200, and the first cross-axis magnetic conductive channel 510 has a first end 511 and a second end 512 arranged oppositely, and the width of the first end 511 is not greater than the width of the second end 512; wherein the rotation direction of the rotor core 100 is the first direction, and the direction from the first end 511 to the second end 512 is the second direction, and the first direction is opposite to the second direction. Such a setting can improve the magnetic circuit in the first cross-axis magnetic conductive channel 510, make the magnetic field distribution more uniform, reduce the iron loss of the motor, thereby improving the performance of the motor, and at the same time reduce the electromagnetic force density of the motor and reduce the torque pulsation of the motor. At the same time, the amount of permanent magnets 300 placed in the curved grooves 200 of the single-layer structure is reduced compared to the amount of permanent magnets 300 of the double-layer structure, thereby reducing the production cost of the motor rotor 10. At the same time, the production efficiency of the motor rotor 10 of the single-layer curved groove 200 structure is also higher than that of the motor rotor 10 of the double-layer curved groove 200 structure.

In one embodiment, a second cross-axis magnetic conductive channel (not shown) is formed between any two adjacent layers of the magnetic barrier holes 410, and the second cross-axis magnetic conductive channel has a third end and a fourth end that are relatively arranged, and the third end is arranged on the same side as the first end 511, and the fourth end is arranged on the same side as the second end 512; the width of the third end is not greater than the width of the fourth end.

Specifically, when multiple layers of magnetic barrier holes 410 are provided in the d-axis direction of the rotor 10, a second cross-axis magnetic conductive channel is formed between any two adjacent layers of the magnetic barrier holes 410. Similarly, the second cross-axis magnetic conductive channel has a third end and a fourth end that are relatively arranged. The positions of the third end and the fourth end are determined by the relative positions of the first end 511 and the second end 512. The positions of the first end 511 and the second end 512 are determined as described above. Setting the width of the third end to be no greater than the width of the fourth end can improve the magnetic circuit in the second cross-axis magnetic conductive channel, further make the magnetic field distribution more uniform, reduce the iron loss of the motor, thereby improving the performance of the motor, and at the same time reduce the electromagnetic force density of the motor and reduce the torque pulsation of the motor.

Please refer to Figures 1 to 4. Further, the width from the first end 511 to the second end 512 is gradually increased, and/or the width from the third end to the fourth end is gradually increased. In this way, the width from the first end 511 to the second end 512 of the first cross-axis magnetic conductive channel 510 can be gradually expanded, which can further make the magnetic field distribution more uniform, avoiding the uneven magnetic field distribution caused by the small width of the first end 511 to the second end 512 of the first cross-axis magnetic conductive channel 510. Similarly, the width from the third end to the fourth end of the second cross-axis magnetic conductive channel is gradually expanded, which can further make the magnetic field distribution more uniform, avoiding the uneven magnetic field distribution caused by the small width of the third end to the fourth end of the second cross-axis magnetic conductive channel. In this way, the iron loss of the motor can be reduced, thereby improving the performance of the motor, while reducing the electromagnetic force density of the motor and reducing the torque pulsation of the motor.

Please refer to FIG. 2 . In one embodiment, a direct-axis magnetic conductive channel 600 is formed between any two adjacent magnetic barrier holes 410 in a layer of magnetic barrier holes 410. Specifically, the magnetic resistance in the d-axis direction where the direct-axis magnetic conductive channel 600 is located is small, has a high magnetic flux, and has a large inductance Ld; while the magnetic resistance in the q-axis direction at the center line of the magnetic barrier hole 410 is very high, and the inductance Lq is small. In this way, the inductance difference between the d-axis and q-axis directions can be increased, that is, the value of (Lq-Ld) in the formula T=mp*(Lq-Ld)*id*iq+mp*ψPM*iq is increased, thereby improving the torque output capacity of the motor. The surface of the magnetic conductive channel can be coated with a magnetic conductive material, so as to achieve a better magnetic conductive effect.

Please refer to FIG. 3. In one embodiment, the thickness of the permanent magnet 300 in the axial direction of the rotor 10d is T. The magnetic barrier hole 410 has a first side 411 and a second side 412 which are arranged opposite to each other. The second side 412 is located on a side of the first side 411 away from the center of the rotor core 100. The distance from the side edge 411 to the second side edge 412 is the thickness H of the magnetic barrier hole 410 , satisfying T＞H.

Specifically, the greater the thickness of the permanent magnet 300 in the axial direction of the rotor 10d, the higher the permanent magnet torque of the motor, thereby increasing the output torque of the motor and the efficiency of the motor. At the same time, in order to ensure that the magnetic path in the cross-axis magnetic conductive channel is not blocked, the thickness of any layer of the magnetic barrier holes 410 should not be too large, so the thickness of the permanent magnet 300 is set to be greater than the thickness of any layer of the magnetic barrier holes 410 in the multi-layer magnetic barrier holes 410. The thickness of the magnetic barrier hole 410 refers to the distance from the first side 411 to the second side 412 of the magnetic barrier hole 410. If the first side 411 and the second side 412 are arranged in parallel, the thickness of the magnetic barrier hole 410 refers to the shortest distance from the first side 411 to the second side 412; if the first side 411 and the second side 412 are not arranged in parallel, the thickness of the magnetic barrier hole 410 refers to the distance from the first side 411 close to the middle part of the magnetic barrier hole 410 to the second side 412; if the magnetic barrier hole 410 is designed in an irregular shape, the thickness of the magnetic barrier hole 410 may be the average value between the maximum distance and the minimum distance from the first side 411 to the second side 412.

Please refer to FIG. 2 . In one embodiment, the first side 411 and/or the second side 412 are straight lines; or, the first side 411 and/or the second side 412 are arc-shaped. Specifically, a plurality of the magnetic barrier holes 410 are arranged at intervals along the circumference of the rotor core 100, and each magnetic barrier hole 410 has a first side 411 and a second side 412 opposite to each other. When the magnetic barrier holes 410 are provided, the first side 411 and the second side 412 may be straight lines, or one of the first side 411 and the second side 412 may be straight lines and the other may be other shapes, or the first side 411 and the second side 412 may be arc-shaped, or one of the first side 411 and the second side 412 may be arc-shaped and the other may be other shapes, and there is no specific limitation on this. The magnetic barrier hole 410 further includes two other side edges connecting the first side edge 411 and the second side edge 412 . The other two side edges have arc-shaped profiles at the connection points with the first side edge 411 and the second side edge 412 , so as to facilitate the passage of the magnetic circuit.

In one embodiment, on a cross section perpendicular to the axial direction of the rotor 10, the thickness of the middle part of the permanent magnet 300 is greater than the thickness of the two ends of the permanent magnet 300. Specifically, the permanent magnet 300 can be set to a structure with a thick middle and thin ends, so that the thickness of the middle part of the permanent magnet 300 is greater than the thickness of the two ends. Taking the arc-shaped permanent magnet 300 as an example, the arc-shaped permanent magnet 300 is usually prone to local demagnetization in the middle inner surface area of the permanent magnet 300. Designing the arc-shaped permanent magnet 300 to be a structure with a thick middle and thin ends can alleviate the local demagnetization phenomenon of the arc-shaped permanent magnet 300. In addition, the use of this unequal thickness permanent magnet 300 design can also prevent the permanent magnet 300 from sliding in the curved groove 200, thereby improving the stability of the permanent magnet 300 installed in the curved groove 200. Furthermore, a cross-axis magnetic conductive channel is formed between a layer of the magnetic barrier hole 410 close to the curved groove 200 and the curved groove 200. If the permanent magnet 300 adopts a structure that is thick in the middle and thin at both ends, the width of the cross-axis magnetic conductive channel will be increased, thereby increasing the q-axis inductance, that is, increasing the value of Lq, so that the inductance difference between Ld and Lq increases, increasing the magnetic resistance torque, and thus improving the torque output capacity of the motor.

In one embodiment, there is a gap between the two ends of the permanent magnet 300 and the two ends of the curved slot 200 in which it is embedded, which effectively avoids the situation where the d-axis armature magnetic potential is concentrated on the ends of the permanent magnet 300, and can well improve the demagnetization current of the motor. The gap can be filled with air, and further, the gap can also be used to fill a non-magnetic medium. Specifically, filling the gap with air or a non-magnetic medium avoids the easy demagnetization and unsaturated magnetization of the ends of the permanent magnet 300, and at the same time, the anti-demagnetization ability of the motor is also improved.

In one embodiment, the thickness of the motor rotor 10 with magnetic barriers along its axial direction is not less than the thickness of the stator along its axial direction (not shown). The permanent magnet 300 is installed in the curved slot 200 of the rotor core 100. The thickness of the motor rotor 10 with magnetic barriers is made thicker, so that the volume of the rotor core 100 for placing the permanent magnet 300 can be larger, thereby improving the permanent magnet torque of the motor and improving the output capacity of the motor.

Please refer to FIG. 4 , in one embodiment, the curved groove 200 is arranged in a U-shape. Specifically, when the curved groove 200 is arranged in a U-shape, the curved groove 200 can be divided into three parts: a left part, a bottom part and a right part. The left part, the bottom part and the right part can be interconnected or blocked from each other, as long as the general shape thereof is ensured to be arranged in a U-shape. The permanent magnet 300 is arranged in a rectangular block shape, because the arc permanent magnet 300 is greatly affected by the material in the molding aspect, and there are many finishing processes in the later molding stage, while the molding and processing processes of the rectangular permanent magnet 300 are relatively simple, so the use of the rectangular permanent magnet 300 can improve production efficiency and has strong versatility. The permanent magnet 300 can be placed in any one of the three parts of the left part, the bottom part and the right part, or in any two of the three parts of the left part, the bottom part and the right part, or in all of the three parts of the left part, the bottom part and the right part, and no specific restrictions are made on this.

In another embodiment, the curved groove 200 is arranged in a V shape (not shown). Specifically, when the curved groove 200 is arranged in a V shape, the curved groove 200 can be divided into a left half and a right half, and the permanent magnet 300 is arranged in a rectangular block shape. The permanent magnet 300 can be installed in the left half of the curved groove 200, can be installed in the right half of the curved groove 200, or can be installed in both the left half and the right half.

Please refer to FIG. 1 , in another embodiment, the curved groove 200 is arranged in an arc shape. Specifically, when the curved groove 200 is arranged in an arc shape, the shape of the permanent magnet 300 can also be arranged in an arc shape, and the shape of the permanent magnet 300 is adapted to the shape of the curved groove 200 , and the permanent magnet 300 is adapted to be installed in the curved groove 200 .

The present application also proposes a compressor, the compressor comprising the permanent magnet assisted synchronous reluctance motor. The specific structure of the permanent magnet assisted synchronous reluctance motor refers to the above embodiment. Since the present compressor adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes made by using the contents of the present application specification and drawings under the application concept of the present application, or directly/indirectly used in other related technical fields are included in the patent protection scope of the present application.

Claims

A permanent magnet assisted synchronous reluctance motor comprises a rotor and a stator sleeved outside the rotor, wherein the stator comprises a stator core and a winding wound on stator teeth, wherein the rotor comprises:

Rotor core;

A plurality of curved grooves are provided on the rotor core and are arranged at intervals along the circumference of the rotor core, and both ends of the curved grooves extend toward the edge of the rotor core;

a plurality of permanent magnets disposed in the plurality of curved grooves; and

A plurality of magnetic barrier groups, wherein the plurality of magnetic barrier groups are arranged on a side of the plurality of curved slots away from the center of the rotor core, the magnetic barrier group comprises at least one layer of magnetic barrier holes arranged at intervals along the d-axis direction of the rotor, the number of magnetic barrier holes in one layer is set to be multiple, and the plurality of magnetic barrier holes are arranged at intervals along the extension direction of the slot wall of the curved slot; a first cross-axis magnetic conductive channel is formed between a layer of magnetic barrier holes close to the curved slot and the curved slot, the first cross-axis magnetic conductive channel having a first end and a second end arranged oppositely, and a width of the first end is not greater than a width of the second end;

The rotation direction of the rotor core is a first direction, the direction from the first end to the second end is a second direction, and the first direction is opposite to the second direction.
The permanent magnet assisted synchronous reluctance motor according to claim 1, wherein a second cross-axis magnetic conductive channel is formed between any two adjacent layers of the magnetic barrier holes, and the second cross-axis magnetic conductive channel has a third end and a fourth end that are arranged opposite to each other, the third end is arranged on the same side as the first end, and the fourth end is arranged on the same side as the second end; the width of the third end is not greater than the width of the fourth end.
The permanent magnet assisted synchronous reluctance motor according to claim 2, wherein the width from the first end to the second end gradually increases, and/or the width from the third end to the fourth end gradually increases.
The permanent magnet assisted synchronous reluctance motor according to any one of claims 1 to 3, wherein a direct-axis magnetic conductive channel is formed between any two adjacent magnetic barrier holes in a layer of the magnetic barrier holes.
The permanent magnet motor according to any one of claims 1 to 4, wherein the thickness of the permanent magnet in the d-axis direction of the rotor is T, the magnetic barrier hole has a first side and a second side that are arranged opposite to each other, the second side is located on a side of the first side away from the center of the rotor core, and the distance from the first side to the second side is the thickness H of the magnetic barrier hole, satisfying T＞H.
The permanent magnet motor according to claim 5, wherein the first side and/or the second side is a straight line; or the first side and/or the second side is an arc.
The permanent magnet motor according to any one of claims 1 to 6, wherein, in a cross section perpendicular to the axial direction of the rotor, the thickness of the middle portion of the permanent magnet is greater than the thickness of both ends of the permanent magnet.
The permanent magnet motor according to any one of claims 1 to 7, wherein there is a gap between both ends of the permanent magnet and both ends of the curved groove in which the permanent magnet is embedded.
The permanent magnet motor according to claim 8, wherein the gap is used to fill with a non-magnetic conductive medium.
The permanent magnet motor according to any one of claims 1 to 9, wherein the thickness of the rotor along the axial direction thereof is not less than the thickness of the stator along the axial direction thereof.
The permanent magnet motor according to any one of claims 1 to 10, wherein the curved groove is arranged in a U shape.
The permanent magnet motor according to any one of claims 1 to 11, wherein the curved groove is arranged in a V-shape.
The permanent magnet motor according to any one of claims 1 to 12, wherein the curved groove is arranged in an arc shape.
A compressor, comprising the permanent magnet assisted synchronous reluctance motor as claimed in any one of claims 1 to 13.