Permanent magnet motors, compressors, and air conditioners

Abstract

This invention discloses a permanent magnet motor, a compressor, and an air conditioner. The permanent magnet motor includes a stator and a rotor. The stator includes a stator core and a stator winding. The stator core includes multiple stator teeth arranged circumferentially around the stator core, with stator slots defined between adjacent stator teeth. The stator winding is wound on the stator teeth. The rotor is spaced apart from the stator. The rotor includes a rotor core and permanent magnets embedded in the rotor core. The maximum diameter of the outer contour of the rotor core's cross-section is D1, and the axial length of the rotor core is L. The rated power of the permanent magnet motor is P. D1, L, and P satisfy: D1 / L ≥ 1.7 and P / (D1) 2 (×L)≥8.5, where P is in W, and D1 and L are in cm. The permanent magnet motor according to the present invention has high power density and operating efficiency, while also facilitating miniaturization and cost reduction.

Description

[0001] This application is a divisional application of the patent application filed on July 27, 2018, with application number 201810843967.4 and invention title "Permanent Magnet Motor, Compressor and Air Conditioner". Technical Field

[0002] This invention relates to the field of household appliance technology, and in particular to a permanent magnet motor, compressor and air conditioner. Background Art

[0003] In the compressor industry, rare-earth permanent magnet motors have the highest power density and efficiency. However, improvements in the power density and efficiency of permanent magnet motors have been limited in related technologies. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a permanent magnet motor that has high power density and operating efficiency, while facilitating miniaturization and cost reduction.

[0005] Another object of the present invention is to provide a compressor for a permanent magnet motor.

[0006] Another object of the present invention is to provide an air conditioner having the above-described compressor.

[0007] According to a first aspect of the present invention, a permanent magnet motor includes: a stator, the stator including a stator core and a stator winding, the stator core including a plurality of stator teeth arranged circumferentially along the stator core, a stator slot defining a space between two adjacent stator teeth, and the stator winding wound on the stator teeth; and a rotor, the rotor being disposed at an internal and external interval from the stator, the rotor including a rotor core and a permanent magnet embedded in the rotor core, the maximum diameter of the outer contour of the cross-section of the rotor core being D1, the axial length of the rotor core being L, and the rated power of the permanent magnet motor being P, wherein D1, L, and P satisfy: D1 / L≥1.7 and P / (D1) 2 ×L)≥8.5, where the unit of P is W, and the units of D1 and L are both cm.

[0008] According to an embodiment of the present invention, the rated power P of the permanent magnet motor is set to satisfy the following conditions: the maximum diameter D1 of the outer contour of the rotor core cross-section and the axial length L of the rotor core 21 are set to satisfy: D1 / L≥1.7 and P / (D1)L / L. 2 With a rotor size of (×L)≥8.5, a flat rotor design is achieved, which is beneficial to improving the power density of the permanent magnet motor, realizing the high efficiency of the permanent magnet motor, and reducing the size of the permanent magnet motor, making it easier to miniaturize the permanent magnet motor and reduce costs.

[0009] According to some embodiments of the present invention, the stator is sleeved on the outside of the rotor, and the maximum diameter of the outer circumferential profile of the cross-section of the stator is D2, wherein D2 satisfies: D2 / L≥3, and the unit of D2 is cm.

[0010] According to some embodiments of the present invention, the stator winding is a concentrated winding, and the conductor of the stator winding is a copper wire.

[0011] According to some embodiments of the present invention, the number of poles of the rotor is Q, wherein Q satisfies: Q≥8.

[0012] According to some embodiments of the present invention, when the number of stator slots is 9, Q satisfies: Q = 8 or Q = 10.

[0013] According to some embodiments of the present invention, the permanent magnet is made of sintered neodymium iron boron.

[0014] According to some embodiments of the present invention, the stator teeth include a yoke and a tooth portion arranged radially along the stator core, the stator winding is wound on the tooth portion, and the yoke portions of two adjacent stator teeth are welded together or pivotally connected.

[0015] According to some embodiments of the present invention, end plates are provided at both ends of the rotor to limit the permanent magnet to move axially along the rotor core, and the end plates are made of non-magnetic material.

[0016] The compressor according to a second aspect of the present invention includes a permanent magnet motor according to the first aspect of the present invention described above.

[0017] According to the compressor of the present invention, by adopting the above-mentioned permanent magnet motor, the operating power of the compressor is improved, and at the same time, the compressor can be miniaturized, saving the space occupied by the compressor.

[0018] An air conditioner according to a third aspect of the present invention includes a compressor according to the second aspect of the present invention described above.

[0019] According to the embodiments of the present invention, by employing the above-described compressor, the air conditioner improves the cooling / heating efficiency of the air conditioner and saves space occupied by the air conditioner.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 This is a partial structural schematic diagram of a permanent magnet motor according to an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 A cross-sectional view of the permanent magnet motor shown;

[0024] Figure 3 yes Figure 2 A cross-sectional view of the rotor shown;

[0025] Figure 4 This is a schematic diagram illustrating the power-volume relationship between a permanent magnet motor according to an embodiment of the present invention and a conventional permanent magnet motor.

[0026] Figure 5 yes Figure 1 Another partial structural schematic diagram of the permanent magnet motor shown;

[0027] Figure 6 yes Figure 1 Another partial structural schematic diagram of the permanent magnet motor shown;

[0028] Figure 7 This is a cross-sectional view of a compressor according to an embodiment of the present invention.

[0029] Figure label:

[0030] Compressor 200, housing 101, air inlet 101a, air outlet 101b, crankshaft 102, compression mechanism 103

[0031] Cylinder 103a, main bearing 103b, auxiliary bearing 103c, piston 103d, balance weight 104.

[0032] Permanent magnet motor 100, central axis of permanent magnet motor 100a,

[0033] Stator 1, Stator Core 11, Stator Winding 12

[0034] Stator slot 110, stator tooth 111, yoke 111a, tooth 111b

[0035] Rotor 2, rotor core 21, permanent magnet slot 21a, permanent magnet 22

[0036] End plate 3

[0037] Insulating end plate 4, mounting post 41, guide part 411, insulating component 5. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] The following is for reference. Figures 1-6 A permanent magnet motor 100 according to an embodiment of the first aspect of the present invention is described.

[0040] like Figures 1-6 As shown, the permanent magnet motor 100 according to an embodiment of the present invention includes a stator 1 and a rotor 2.

[0041] The stator 1 includes a stator core 11 and a stator winding 12. The stator core 11 includes multiple stator teeth 111 arranged circumferentially along the stator core 11. A stator slot 110 is defined between two adjacent stator teeth 111. The stator winding 12 is wound on the stator teeth 111. The rotor 2 is spaced apart from the stator 1. The rotor 2 includes a rotor core 21 and a permanent magnet 22 embedded in the rotor core 21. The maximum diameter of the outer contour of the rotor core 21 is D1, the axial length of the rotor core 21 is L, and the rated power of the permanent magnet motor 100 is P. D1, L, and P satisfy: D1 / L≥1.7, and P / (D1 / L)≥1.7. 2 ×L)≥8.5, where the unit of P is W (watts), and the units of D1 and L are both cm (centimeters).

[0042] For example, such as Figures 1-4 As shown, multiple stator teeth 111 can be connected end to end along the axial direction of the stator core 11, and the stator winding 12 is located in the stator slot 110; multiple permanent magnet slots 21a can be formed on the rotor core 21, which are spaced apart along the circumference of the rotor core 21. Each permanent magnet slot 21a can penetrate through both end faces of the rotor core 21 along the axial direction of the rotor core 21, and multiple permanent magnets 22 can be correspondingly embedded in the multiple permanent magnet slots 21a, so that at least one permanent magnet 22 is embedded in each permanent magnet slot 21a to form a magnetic pole.

[0043] The outer contour of the rotor core 21's cross-section can be roughly circular, and the center of the rotor 2's cross-section can be the center of the aforementioned circle. D1 can be the maximum diameter of the outer contour of the rotor core 21's cross-section. The relationship between D1 and the axial length L of the rotor core 21 satisfies D1 / L≥1.7 ("1.7" is a dimensionless coefficient). To a certain extent, this improves the flatness of the rotor 2, realizing the flattened design of the rotor 2, which is beneficial to improving the power density of the permanent magnet motor 100, thereby achieving the high efficiency of the permanent magnet motor 100. However, since D1 / L≥1.7, it is not convenient to realize the miniaturization design of the permanent magnet motor 100 to a certain extent. By setting the rated power P of the permanent magnet motor 100 to satisfy P / (D1)... 2 ×L)≥8.5 (“8.5” is in W / cm²) 3 This design allows for a smaller rotor 2 with the same rated power, thereby reducing the volume of the permanent magnet motor 100. Compared to the permanent magnet motor 100 of the conventional technology, the volume of the permanent magnet motor 100 of this application can be reduced by about 10%. This achieves a miniaturized design of the permanent magnet motor 100 while ensuring its efficient operation, thus reducing the cost of the permanent magnet motor 100, especially the material cost.

[0044] For a permanent magnet motor 100, its rated power P and (D1) 2 The ratio of (×L) can be a fixed value; "rated power P" can refer to the input power of permanent magnet motor 100 when it is applied to compressor 200 or compressor 200 is applied to air conditioner, under the rated cooling condition of air conditioner; "multiple" means two or more.

[0045] According to an embodiment of the present invention, the permanent magnet motor 100, by setting the maximum diameter D1 of the outer contour of the rotor core 21 cross-section and the axial length L of the rotor core 21, the rated power P of the permanent magnet motor 100 is set to satisfy: D1 / L≥1.7, and P / (D1) 2 The rotor 2 has a flat design with a diameter of (×L)≥8.5, which helps to improve the power density of the permanent magnet motor 100, achieve high efficiency of the permanent magnet motor 100, and reduce the volume of the permanent magnet motor 100, making it easier to miniaturize the permanent magnet motor 100 and reduce costs.

[0046] Alternatively, as Figure 1 and Figure 2As shown, the stator 1 is mounted on the outside of the rotor 2. In this case, the permanent magnet motor 100 is an internal rotor motor. The maximum diameter of the outer circumference of the stator 1's cross-section is D2, which satisfies: D2 / L≥3 ("3" is a dimensionless coefficient). The unit of D2 is cm. This improves the flatness of the stator 1 to a certain extent, achieving a flat design that further enhances the power density of the permanent magnet motor 100 and enables its efficient operation. The axial length of the stator core 11 can be approximately equal to the axial length L of the rotor core 21. That is, the axial length of the stator core 11 is equal to the axial length L of the rotor core 21, or there is a small difference between the axial lengths of the stator core 11 and the rotor core 21.

[0047] It is understandable that the rotor 2 can be mounted outside the stator 1, in which case the permanent magnet motor 100 is an external rotor motor.

[0048] Specifically, the stator winding 12 is a concentrated winding. Concentrated windings can be applied to salient-pole stators 1. They are typically wound into rectangular coils, shaped by wrapping with yarn tape, and then impregnated and dried before being wound onto the stator 1. This reduces the processing cost of the stator 1 and easily meets the miniaturization design requirements of the permanent magnet motor 100. Furthermore, the shorter end length of the concentrated winding reduces the resistance of the permanent magnet motor 100, ensuring its efficiency. The conductor of the stator winding 12 is copper wire, which has good conductivity and mechanical properties and is easy to process.

[0049] Optionally, the number of poles of rotor 2 is Q, where Q satisfies: Q≥8. Compared with rotor 2 with 4 or 6 magnetic poles in the traditional technology, the power density of permanent magnet motor 100 is further effectively improved due to the increase in the number of magnetic poles. At the same time, the copper loss of permanent magnet motor 100 is reduced, which is conducive to further realizing the high efficiency of permanent magnet motor 100. Moreover, the structural size of rotor 2 can be reduced, which is convenient for further miniaturization of permanent magnet motor 100.

[0050] Alternatively, the number of poles Q of rotor 2 satisfies: 8≤Q≤14, thereby avoiding a significant increase in iron loss of permanent magnet motor 100 due to excessive number of poles of rotor 2, which would suppress the efficiency improvement of permanent magnet motor 100 to a certain extent, thus ensuring the performance of permanent magnet motor 100.

[0051] Specifically, when there are 9 stator slots 110, Q satisfies either Q = 8 or Q = 10. That is, when there are 9 stator slots 110, the number of poles Q of rotor 2 is 8, or when there are 9 stator slots 110, the number of poles Q of rotor 2 is 10 (for example, such as...). Figure 1 (As shown).

[0052] Of course, the number of stator slots 110 and rotor poles 2 can be set in other ways. For example, there can be 12 stator slots 110 and 14 poles Q of rotor 2; or, there can be 12 stator slots 110 and 10 poles Q of rotor 2. But it is not limited to these.

[0053] Optionally, the permanent magnet 22 is made of sintered neodymium iron boron, which gives the permanent magnet 22 excellent magnetic properties and ensures the reliability of the permanent magnet 22 in use.

[0054] In some embodiments of the present invention, such as Figure 1 As shown, the stator teeth 111 include yoke portions 111a and teeth 111b arranged radially along the stator core 11. The yoke portions 111a of multiple stator teeth 111 are connected end to end in sequence to form an annular stator yoke. The yoke portions 111a of two adjacent stator teeth 111 can be welded together or pivotally connected. The teeth 111b of multiple stator teeth 111 are arranged at intervals along the circumference of the permanent magnet motor 100. The stator winding 12 can be wound on the teeth 111b of the stator teeth 111 to be located in the stator slot 110. When the yokes 111a of two adjacent stator teeth 111 are pivotally connected, one circumferential end of the yoke 111a of one of the two adjacent stator teeth 111 can be provided with a pivot protrusion, and one circumferential end of the yoke 111a of the other of the two adjacent stator teeth 111 can be formed with a pivot opening. The pivot protrusion can be correspondingly fitted into the pivot opening, so that one of the two adjacent stator teeth 111 can rotate relative to one of the two adjacent stator teeth 111 around the central axis of the pivot opening within a certain range, so as to facilitate the rapid assembly of the stator core 11 and improve the assembly efficiency of the stator 1.

[0055] Specifically, end plates 3 are provided at both axial ends of the rotor 2 to limit the axial movement of the permanent magnet 22 along the rotor core 21. The end plates 3 are made of non-magnetic material. For example, in Figure 2 and Figure 3 In the example, there are two end plates 3, each of which can be formed as a plate structure. The end plates 3 can be set tightly against the end face of the rotor core 21 to block the movement of the permanent magnet 22, thereby achieving axial restraint of the permanent magnet 22, preventing the permanent magnet 22 from detaching from the rotor core 21, and ensuring the structural stability of the rotor 2. The end plates 3 are made of non-magnetic materials, such as stainless steel, so that they can shield the rotor 2 from magnetic leakage.

[0056] The compressor 200 according to a second aspect embodiment of the present invention includes the permanent magnet motor 100 according to the first aspect embodiment of the present invention described above. The compressor 200 can be applied to household appliances, such as air conditioners; the compressor 200 can be a vertical compressor 200; the compressor 200 can be a single-cylinder compressor 200 or a multi-cylinder compressor 200. However, it is not limited thereto.

[0057] For example, such as Figure 7 As shown, the compressor 200 can be a single-cylinder compressor 200 and a rotary compressor 200. The compressor 200 may also include a housing 101, a crankshaft 102, and a compression mechanism 103. The crankshaft 102, the compression mechanism 103, and the permanent magnet motor 100 are all housed inside the housing 101. An air outlet 101b may be formed on the top of the housing 101, and an air inlet 101a may be formed on the peripheral wall of the housing 101. The crankshaft 102 passes through the permanent magnet motor 100 and the compression mechanism 103, so that when the permanent magnet motor 100 is running, the rotor 1 rotates to drive the rotor 1 through the crankshaft 102. The compression mechanism 103 operates to achieve the intake, compression, and discharge of refrigerant. The compression mechanism 103 includes a cylinder 103a and a main bearing 103b and a secondary bearing 103c located at opposite ends of the cylinder 103a. A compression chamber is defined within the compression mechanism 103, and an inlet and an outlet communicating with the compression chamber are formed on the compression mechanism. A piston 103d is provided within the compression chamber, and an eccentric portion of the crankshaft 102 passes through the piston 103d to drive the piston 103d to rotate eccentrically. The inlet communicates with the air inlet 101a so that refrigerant flows into the compression chamber through the air inlet 101a and the inlet for compression. A balance block 104 can be provided at the end of the rotor 2 of the permanent magnet motor 100 to achieve dynamic balance of the crankshaft 102.

[0058] According to the present invention, the compressor 200, by employing the aforementioned permanent magnet motor 100, improves the operating power of the compressor and enables a miniaturized design of the compressor, saving space occupied by the compressor.

[0059] An air conditioner according to a third aspect embodiment of the present invention includes a compressor according to the second aspect embodiment described above. Specifically, the air conditioner may include a housing, and the compressor may be disposed within the housing. The air conditioner can perform cooling and / or heating, and may be a floor-standing air conditioner, a wall-mounted air conditioner, a recessed air conditioner, or a window air conditioner, etc.

[0060] According to the embodiments of the present invention, by employing the compressor 200 described above, the air conditioner improves the cooling / heating efficiency of the air conditioner and saves space occupied by the air conditioner.

[0061] Other configurations and operations of the air conditioner according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0062] The following is for reference. Figures 1-6 The permanent magnet motor 100 according to an embodiment of the present invention is described in detail with reference to a specific example. It is to be understood that the following description is merely illustrative and not intended to limit the invention in any specific way.

[0063] In the description of this invention, it should be understood that the terms "center", "lateral", "length", "upper", "lower", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0064] like Figures 1-6 As shown, the permanent magnet motor 100 includes a rotor 1 and a stator 2. The rotor 1 includes a rotor core 11 and ten permanent magnets 12. The outer contour of the rotor core 11 is circular. The rotor core 11 is formed by stacking multiple second electromagnetic steel plates along the axial direction of the permanent magnet motor 100. The iron loss of the second electromagnetic steel plates magnetized to 1.5T at a frequency of 50Hz does not exceed 2.5W / kg. Ten permanent magnet slots 11a are formed on the rotor core 11 at circumferential intervals. Each permanent magnet slot 11a can penetrate through both end faces of the rotor core 11 along the axial direction of the rotor core 11. The ten permanent magnets 12 are embedded one-to-one in the ten permanent magnet slots 11a, so that the ten permanent magnets 12 are embedded in the rotor core 11, and the number of poles of the rotor 1 is Q=10. Each permanent magnet 12 is made of sintered neodymium iron boron.

[0065] The stator 2 is mounted outside the rotor 1. The stator 2 includes a stator core 21 and a stator winding 22. The stator core 21 is formed by stacking multiple first electromagnetic steel plates along the axial direction of the permanent magnet motor 100. The iron loss of the first electromagnetic steel plates magnetized to 1.5T at a frequency of 50Hz is measured to be 2.3W / kg. The stator core 21 includes nine stator teeth 211 arranged circumferentially along the permanent magnet motor 100. Each stator tooth 211 includes a yoke 211a and a tooth 211b arranged radially opposite to each other along the permanent magnet motor 100. 211b is located inside the yoke 211a. The yokes 211a of multiple stator teeth 211 are connected end to end to form a ring-shaped stator yoke. The teeth 211b of multiple stator teeth 211 are spaced apart along the circumference of the permanent magnet motor 100. Stator slots 210 are defined between two adjacent stator teeth 211, i.e., there are nine stator slots 210. The stator winding 22 is wound on the teeth 211b of the stator teeth 211 and is located in the stator slots 210. The stator winding 22 is a concentrated winding, and the conductor of the stator winding 22 is a copper wire. An insulating element 5 is provided in the stator slots 210 to separate the coil of the stator winding 22 from the stator teeth 211, thereby achieving insulation. The insulating element 5 can be insulating paper.

[0066] The maximum diameter of the outer contour of the rotor core 21 is D1, the axial length of the rotor core 21 is L, the rated power of the permanent magnet motor 100 is P, and the maximum diameter of the outer contour of the stator 1 is D2. D1, L, P, and D2 satisfy: D1 / L ≥ 1.7, P / (D1 / L) ≥ 1.7, and P / (D1 / L) ≥ 1.7. 2 ×L)≥8.5 and D2 / L≥3, the unit of P is W, and the units of D1, L and D2 are all cm.

[0067] It should be noted that the direction “outside” refers to the direction away from the central axis 100a of the permanent magnet motor, and its opposite direction is defined as “inside”; the “axial direction of the permanent magnet motor 100” is parallel to the extension direction of the central axis 100a of the permanent magnet motor.

[0068] like Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, the rotor 2 has end plates 3 at both axial ends to limit the movement of the permanent magnet 22 along the axial direction of the rotor core 21. The end plates 3 are made of stainless steel. The stator 2 has end plates 3 at both axial ends (e.g., Figure 5 The upper and lower ends of the stator core 21 are respectively provided with insulating end plates 4. The two insulating end plates 4 are respectively installed at the end faces of the two ends of the stator core 21 along the axial direction. Each insulating end plate 4 forms an insulating skeleton, and each insulating end plate 4 is provided with multiple mounting posts 41 spaced apart along the circumference of the stator core 21. Each mounting post 41 can extend towards the stator core 21 along the axial direction. Multiple mounting holes are formed on the end faces of the two ends of the stator core 21. Each mounting hole can be formed by a part of the end face of the stator core 21 being recessed. The multiple mounting posts 41 are matched one-to-one in the multiple mounting holes, so that the insulating end plates 4 can be quickly installed on the stator core 21.

[0069] Each mounting post 41 can be formed as a cylindrical structure, and each mounting post 41 can be provided with a guide portion 411 at its free end. The outer peripheral wall of the guide portion 411 forms a guide surface. The guide portion 411 can be formed as a frustum structure, so that the cross-sectional area of ​​the guide portion 411 gradually decreases along the axial direction of the stator core 21 from the end of the guide portion 411 away from the center of the stator core 21 toward the end of the guide portion 411 adjacent to the center of the stator core 21. This allows the guide surface to play a good guiding role during the installation of the insulating end plate 4, further improving the installation efficiency of the insulating end plate 4.

[0070] The permanent magnet motor 100 according to an embodiment of the present invention, compared with the permanent magnet motor of the conventional technology, has a corresponding D1 / L≤1.5 and P / (D1) 2With a power density of (×L)≤8, the power density of the permanent magnet motor 100 in this application is further and effectively improved, thereby effectively improving the efficiency of the permanent magnet motor 100, facilitating the realization of high efficiency of the permanent magnet motor 100, and from... Figure 4 As can be seen from this, under the same rated input power P0, the permanent magnet motor 100 of this application corresponds to (D1) 2 The ×L value is compared to the (D1) value of a traditional permanent magnet motor. 2 The smaller ×L value results in a smaller volume for the permanent magnet motor 100 of this application, achieving miniaturization of the permanent magnet motor 100 and reducing costs.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A permanent magnet motor, characterized in that, include: The stator includes a stator core and a stator winding. The stator core includes a plurality of stator teeth arranged circumferentially along the stator core. A stator slot is defined between two adjacent stator teeth. The stator winding is wound on the stator teeth. An insulating element is provided in the stator slot to separate the coil of the stator winding from the stator teeth. The rotor is spaced apart from the stator. The rotor includes a rotor core and permanent magnets embedded in the rotor core. The maximum diameter of the outer cross-section of the rotor core is D1, and the axial length of the rotor core is L. The rated power of the permanent magnet motor is P. D1, L, and P satisfy the following: D1 / L≥1.7, and Wherein P is in W, and D1 and L are both in cm.

2. The permanent magnet motor according to claim 1, characterized in that, The stator is sleeved on the outside of the rotor, and the maximum diameter of the outer circumferential profile of the stator cross section is D2, wherein D2 satisfies: D2 / L≥3, and the unit of D2 is cm.

3. The permanent magnet motor according to claim 1, characterized in that, The stator winding is a concentrated winding, and the conductor of the stator winding is a copper wire.

4. The permanent magnet motor according to claim 1, characterized in that, The rotor has Q poles, and Q satisfies: Q≥8.

5. The permanent magnet motor according to claim 4, characterized in that, When there are 9 stator slots, Q satisfies either Q=8 or Q=10.

6. The permanent magnet motor according to claim 1, characterized in that, The permanent magnet is made of sintered neodymium iron boron.

7. The permanent magnet motor according to claim 1, characterized in that, The stator teeth include a yoke and a tooth portion arranged radially along the stator core. The stator winding is wound on the tooth portion, and the yoke portions of two adjacent stator teeth are welded together or pivotally connected.

8. The permanent magnet motor according to any one of claims 1-7, characterized in that, The rotor is provided with end plates at both ends of its axial direction to limit the movement of the permanent magnet along the axial direction of the rotor core. The end plates are made of non-magnetic material.

9. A compressor, characterized in that, Includes a permanent magnet motor according to any one of claims 1-8.

10. An air conditioner, characterized in that, Includes the compressor according to claim 9.

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