Electric machine, compressor and refrigeration plant

Abstract

The application discloses a motor, a compressor and a refrigeration device, wherein the motor comprises a stator and a rotor, the stator comprises a plurality of stator teeth which are arranged at intervals, and the stator teeth are provided with tooth shoes at one end of the shaft center of the stator; the rotor is provided with a plurality of mounting grooves, the mounting grooves are arranged at intervals along the circumference of the rotor, permanent magnets are mounted in the mounting grooves, the opposite ends of the mounting grooves are provided with magnetic barrier grooves, the two magnetic barrier grooves extend towards the d-axis, the included angle between the two ends of the two magnetic barrier grooves which extend towards each other and the line connecting the center of the rotor is θ1, the included angle between the opposite ends of the tooth shoes and the line connecting the center of the rotor is θ2, and |θ1-θ2|<a preset angle. The technical scheme aims to improve the utilization rate of the magnets.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and particularly to a motor, compressor and refrigeration equipment. Background Technology

[0002] In recent years, due to the vigorous development of clean energy and new energy vehicles, permanent magnet synchronous motors based on neodymium iron boron magnets have been more widely used, leading to a significant increase in global demand for rare earth materials, as well as a substantial rise in the price of rare earth elements. Neodymium iron boron magnets are one of the three key materials for permanent magnet motors, and with the rise in rare earth element prices, the cost of motor materials has increased. Therefore, how to improve magnet utilization and maximize the material properties of magnets is an urgent and ongoing issue in motor design. Summary of the Invention

[0003] The main objective of this invention is to propose an electric motor that aims to improve the utilization rate of magnets.

[0004] To achieve the above objectives, the present invention provides a motor comprising:

[0005] The stator includes a plurality of spaced stator teeth, each stator tooth having a toothed shoe at one end facing the stator axis;

[0006] The rotor has multiple mounting slots arranged at intervals along its circumference. Permanent magnets are installed in the mounting slots. Magnetic barrier slots are provided at opposite ends of each mounting slot, and both magnetic barrier slots extend towards the d-axis. The angle between the lines connecting the two opposite ends of the two magnetic barrier slots to the center of the rotor is θ1. The angle between the lines connecting the opposite ends of the toothed shoe to the center of the rotor is θ2. Then, |θ1-θ2| < a preset angle.

[0007] Optionally, the preset angle is less than or equal to 2°.

[0008] Optionally, the stator has Q stator teeth, and the rotor has 2P mounting slots, where Q = 12 and 2P = 8.

[0009] Optionally, if the tooth width of the stator tooth is bt, the inner diameter of the stator is D, and the residual magnetism of the permanent magnet is Br, then |bt-Br*θ1*D*π / 865|<0.5.

[0010] Optionally, if the width of the permanent magnet is bM and the inner diameter of the stator is D, then 0.7 < 4P * bM / (D * π) < 0.78 is satisfied.

[0011] Alternatively, 4P*bM / (D*π)=0.75.

[0012] Optionally, the magnetic barrier groove also extends in a direction away from the d-axis.

[0013] Optionally, the mounting groove includes a first section and a second section that are connected and set at an angle, the opening of the angle formed by the first section and the second section being disposed away from the rotor shaft center, and a permanent magnet is installed in each of the first section and the second section.

[0014] Optionally, a demagnetization zone is provided between the first segment and the second segment, so that the two permanent magnets are arranged at a relative interval.

[0015] Optionally, the residual magnetism of the permanent magnet is Br, and Br≥1.3T.

[0016] The present invention also proposes a compressor comprising the motor described above.

[0017] The present invention also proposes a refrigeration device, including the compressor described above.

[0018] The technical solution of this invention involves setting multiple stator teeth spaced apart on the inner circumference of the stator. The end of the stator teeth facing the axis of the stator has a tooth shoe. The armature magnetic field generated by the stator winding mainly acts on the rotor through the tooth shoe. The rotor has multiple mounting slots arranged at intervals along the circumference of the rotor. Permanent magnets are installed in the mounting slots. Magnetic barrier slots are provided at both ends of the mounting slots, and both magnetic barrier slots extend towards the d-axis, thereby increasing the length of the magnetic isolation bridge and reducing magnetic leakage. However, if the magnetic barrier slots extend too far along the d-axis, they will encroach on the space of the silicon steel in which the permanent magnet transmits the main magnetic flux to the stator. Therefore, the angle between the two ends of the magnetic barrier slots extending towards each other and the line connecting them to the rotor center is θ1, and the angle between the two ends of the toothed shoe and the line connecting them to the rotor center is θ2. Then, |θ1-θ2| < the preset angle, so that the area of ​​the silicon steel between the two magnetic barrier slots opposite each other about the d-axis and the area of ​​the toothed shoe are close to the preset values. This ensures that the area of ​​the permanent magnet magnetic field transmitted from the rotor to the stator and the area of ​​the armature magnetic field transmitted from the stator to the rotor are within the preset range, thereby ensuring the transmission efficiency between the rotor and the stator, reducing magnetic leakage, improving magnet utilization, and improving motor performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the rotor structure in one embodiment of the motor of the present invention;

[0021] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0022] Figure 3 for Figure 1 A schematic diagram of the stator structure in a Chinese electric motor.

[0023] Explanation of icon numbers:

[0024] label name label name 110 stator 122 Magnetic barrier trough 111 stator teeth 123 Magnetic bridge 112 Toothed Boots 124 First paragraph 113 stator slot 125 Second paragraph 120 Rotor 126 Demagnetization zone 121 Mounting slot 130 permanent magnet

[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0028] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the word "and / or" throughout the text means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0029] In current technologies, with the vigorous development of clean energy and new energy vehicles, permanent magnet synchronous motors based on neodymium iron boron magnets have gained wider application. The global market demand for rare earth materials has increased significantly, and the price of rare earth elements has also risen sharply. This has led to an increase in the cost of motor materials. Therefore, how to improve magnet utilization efficiency and maximize the material properties of magnets has become an urgent and ongoing issue in motor design. Many factors affect magnet utilization efficiency, one of the most critical being how to reduce rotor leakage flux.

[0030] In view of this, the present invention proposes an electric motor that reduces the leakage flux of the rotor 120 and improves the utilization rate of the magnet.

[0031] In embodiments of the present invention, such as Figures 1 to 3 As shown, the motor includes a stator 110 and a rotor 120. The stator 110 includes a plurality of spaced stator teeth 111, and one end of the stator teeth 111 facing the axis of the stator 110 has a toothed shoe 112. The rotor 120 is provided with a plurality of mounting slots 121, which are arranged at intervals along the circumference of the rotor 120. The permanent magnet 130 is installed in the mounting slot 121. Both ends of the mounting slot 121 are provided with magnetic barrier slots 122, and both magnetic barrier slots 122 extend toward the d-axis. The angle between the two ends of the two magnetic barrier slots 122 extending toward each other and the line connecting them to the center of the rotor 120 is θ1. The angle between the two ends of the toothed shoe 112 and the line connecting them to the center of the rotor 120 is θ2. Then |θ1-θ2| < a preset angle.

[0032] Specifically, the inner circumference of the stator 110 is formed with a plurality of spaced stator teeth 111, and a stator slot 113 is formed between two adjacent stator teeth 111, so that the stator winding passes through the stator slot 113 and is wound on the stator teeth 111. The end of the stator teeth 111 facing the axis of the stator 110 has a tooth shoe 112. When the stator winding is energized, the stator winding generates an armature magnetic field, which is transmitted to the rotor 120 along the tooth shoe 112 of the stator core 110. Magnetic barrier slots 122 are provided at both ends of the mounting slot 121, thereby forming a magnetic isolation bridge 123 structure, which reduces magnetic leakage. The longer the magnetic isolation bridge 123 structure is, the better its effect in reducing magnetic leakage. Therefore, both magnetic barrier slots 122 extend towards the d-axis, thereby increasing the length of the magnetic isolation bridge 123 and reducing magnetic leakage. However, if the extension distance of the magnetic barrier slot 122 towards the d-axis is too long, it will also encroach on the space of the silicon steel in which the permanent magnet 130 transmits the main magnetic flux to the stator 110. Since the stator 110 mainly transmits magnetic force to the rotor 120 through the toothed shoe 112, the area of ​​the silicon steel between the two magnetic barrier slots 122 opposite to each other about the d-axis and the area of ​​the toothed shoe 112 are close to the preset value. That is, the angle between the two ends of the two magnetic barrier slots 122 extending towards each other and the line connecting them to the center of the rotor 120 is θ1, and the angle between the two ends of the toothed shoe 112 and the line connecting them to the center of the rotor 120 is θ2. Then |θ1-θ2|< the preset angle, thereby ensuring the transmission efficiency between the rotor 120 and the stator 110, reducing magnetic leakage, improving the utilization rate of the magnet, and improving the performance of the motor.

[0033] In this embodiment, the magnetic barrier grooves 122 are disposed at opposite ends of the mounting grooves 121. In this embodiment, the magnetic barrier grooves 122 and the mounting grooves 121 are connected. In other embodiments, the magnetic barrier grooves 122 and the mounting grooves 121 may be disposed at relative intervals. Furthermore, in this embodiment, the plurality of stator teeth 111 are uniformly arranged along the circumference of the stator 110; and / or, the plurality of mounting grooves 121 are uniformly arranged along the circumference of the rotor 120.

[0034] Furthermore, in one embodiment, the preset angle is less than or equal to 2°. To ensure that the area of ​​the silicon steel between the two magnetic barrier slots 122 opposite to each other about the d-axis is as close as possible to the area of ​​the toothed shoe 112, and to ensure good transmission efficiency of the main magnetic flux, thereby improving the torque of the rotor 120 and improving the performance of the motor, the preset angle is less than or equal to 2°, that is, |θ1-θ2|<2°. In other words, the angle θ1 formed by the lines connecting the ends of the two magnetic barrier slots 122 opposite to each other about the d-axis to the center of the rotor 120 can be slightly larger than the angle θ2 formed by the lines connecting the opposite ends of the toothed shoe 112 to the center of the rotor 120, or slightly smaller than the angle θ2 formed by the lines connecting the opposite ends of the toothed shoe 112 to the center of the rotor 120.

[0035] The technical solution of the present invention provides a plurality of stator teeth 111 spaced apart on the inner circumference of the stator 110. One end of the stator teeth 111 facing the axis of the stator 110 has a toothed shoe 112. The armature magnetic field generated by the stator winding mainly acts on the rotor 120 through the toothed shoe 112. The rotor 120 is provided with a plurality of mounting slots 121, which are arranged at intervals along the circumference of the rotor 120. The permanent magnet 130 is installed in the mounting slot 121. Magnetic barrier slots 122 are provided at both ends of the mounting slot 121, and both magnetic barrier slots 122 extend toward the d-axis, thereby increasing the length of the magnetic isolation bridge 123 and reducing magnetic leakage. However, if the magnetic barrier slot 122 extends too far along the d-axis, it will encroach on the space of the silicon steel in which the permanent magnet 130 transmits the main magnetic flux to the stator 110. Therefore, the angle between the two ends of the two magnetic barrier slots 122 extending towards each other and the line connecting them to the center of the rotor 120 is θ1, and the angle between the two ends of the toothed shoe 112 and the line connecting them to the center of the rotor 120 is θ2. Then, |θ1-θ2| < the preset angle, so that the area of ​​the silicon steel between the two magnetic barrier slots 122 facing each other about the d-axis and the area of ​​the toothed shoe 112 are close to the preset values. This ensures that the area of ​​the permanent magnet field transmitted from the rotor 120 to the stator 110 and the area of ​​the armature magnetic field transmitted from the stator 110 to the rotor 120 are within the preset range, thereby ensuring the transmission efficiency between the rotor 120 and the stator 110, reducing magnetic leakage, improving magnet utilization, and improving motor performance.

[0036] In one embodiment, refer again Figures 1 to 3 The stator 110 has Q stator teeth 111, and the rotor 120 has 2P mounting slots 121, where Q = 12 and 2P = 8. In this design, the motor adopts a 12-slot, 8-pole design. In existing technology, the optimal tooth magnetic flux density for a 12-slot, 8-pole motor is around 1.6T. If the tooth magnetic flux density is too high, it may lead to a significant loss of iron material in the permanent magnet 130, resulting in increased usage of the permanent magnet 130 and no advantage in motor efficiency. If the tooth magnetic flux density is too low, it may lead to a significant consumption of copper material in the permanent magnet 130, resulting in a significant loss in motor efficiency. Therefore, to ensure motor efficiency, a magnetic flux density design around 1.6T is preferable.

[0037] Furthermore, in one embodiment, the tooth width of stator tooth 111 is bt, the inner diameter of stator 110 is D, and the residual magnetism of permanent magnet 130 is Br, then |bt-Br*θ1*D*π / 865|<0.5 is satisfied. Specifically, |bt-Br*θ1*D*π / 865|<0.5 is mainly used to limit the relative magnitudes of the tooth width bt of stator tooth 111, the inner diameter D of stator 110, and the residual magnetism Br of permanent magnet 130, thereby ensuring that the losses of stator 110 (hereinafter referred to as iron losses) and the losses of stator windings wound on stator 110 (hereinafter referred to as copper losses) are within a suitable range, thereby ensuring the performance and working efficiency of the motor. Wherein, 865 is an empirical constant, the specific value of which depends on the design of the motor slots and poles. Since this embodiment is mainly designed for a motor with a 12-slot, 8-pole design, its value is taken as 865 here. As shown in the table below, it represents the influence of the relative relationship between the tooth width bt of stator tooth 111, the inner diameter D of stator 110, and the residual magnetism Br of permanent magnet 130 on iron loss and copper loss when the motor is designed with a 12-slot, 8-pole design.

[0038]

[0039] As shown in the table above, if the tooth width bt of stator tooth 111 is too large, the area of ​​stator slot 113 will decrease, resulting in a decrease in the magnetic flux density of stator tooth 111. This leads to a decrease in iron loss and an increase in copper loss, but also an increase in total loss and a decrease in motor efficiency. Therefore, the tooth width of stator tooth 111 should be appropriately reduced and the magnetic flux density of stator tooth 111 should be increased to increase iron loss and thus reduce copper loss to improve motor efficiency. The remanent magnetism of permanent magnet 130 is Br (hereinafter referred to as remanent magnetism Br), representing the remanent magnetism Br of permanent magnet 130 at 20℃. Preferably, the remanent magnetism Br is around 1.3T. If the remanent magnetism Br is too large, it will lead to an increase in air gap magnetic flux density, and the magnetic flux density of stator tooth 111 and yoke. At this time, the increased magnetic flux density of stator tooth 111 will exacerbate the saturation of silicon steel, not only causing a sharp increase in iron loss and a decrease in motor efficiency, but also causing changes in magnetic permeability and inductance due to the saturation of stator tooth 111. Under overload conditions, this may cause control instability, leading to the motor's inability to operate normally. If the inner diameter D of the stator 110 is too large, as the inner diameter D of the stator 110 increases, if the width bt of the stator teeth 111 remains unchanged, the area of ​​the stator slots 113 will decrease, resulting in a decrease in the magnetic flux density of the stator teeth 111. This will lead to a decrease in the iron loss and an increase in the copper loss of the motor, which will also cause a decrease in motor efficiency.

[0040] Furthermore, if the width of the permanent magnet 130 is bM and the inner diameter of the stator 110 is D, then 0.7 < 4P*bM / (D*π) < 0.78 is satisfied. Specifically, 4P*bM is the total width of the permanent magnets 130 in the rotor 120, and D*π is the inner diameter circumference of the stator 110. Since the motor adopts a 12-slot 8-pole design in this embodiment, the ratio of the total width of the permanent magnets 130 in the rotor 120 to the inner diameter circumference of the stator 110 must be within a suitable range to further reduce the amount of permanent magnets 130 used while minimizing leakage flux and ensuring a reasonable tooth magnetic density design. Therefore, 0.7 < 4P*bM / (D*π) < 0.78, thereby reducing the width of the permanent magnets 130, reducing the amount of permanent magnets 130 used, reducing material waste, and lowering the manufacturing cost of the motor.

[0041] Preferably, 4P*bM / (D*π)=0.75. Design and continuous testing have shown that when 4P*bM / (D*π)=0.75, it achieves a good reduction in magnetic leakage and a reasonable tooth magnetic density design, while also reducing the width of the permanent magnet 130, thereby reducing the amount of permanent magnet 130 used, reducing material waste, and lowering the manufacturing cost of the motor.

[0042] In one embodiment, the magnetic barrier groove 122 also extends in a direction away from the d-axis. Specifically, the magnetic barrier groove 122 also extends in a direction away from the d-axis, that is, it also extends in a direction towards the q-axis. Because the extension of the magnetic barrier groove 122 towards the d-axis may encroach on the space of the silicon steel in which the permanent magnet 130 transmits the main magnetic flux to the stator 110, in order to further increase the length of the isolation bridge and reduce magnetic leakage, the magnetic barrier groove 122 also extends in a direction away from the d-axis. Moreover, in order to make the width of the magnetic isolation bridge 123 more uniform and improve the magnetic isolation effect, preferably, the contour of the side of the magnetic barrier region near the edge of the rotor 120 is arranged approximately parallel to the edge contour of the rotor 120, and the width of the magnetic isolation bridge 123 can be as equal as possible to the thickness of the stator 110 lamination, thereby reducing magnetic leakage.

[0043] In one embodiment, the mounting groove 121 includes a first segment 124 and a second segment 125 that are connected and set at an angle. The opening of the angle formed by the first segment 124 and the second segment 125 is located away from the axis of the rotor 120. A permanent magnet 130 is installed in both the first segment 124 and the second segment 125. Specifically, the mounting groove 121 includes a first segment 124 and a second segment 125 that are connected and set at an angle. The opening of the angle formed by the first segment 124 and the second segment 125 is located away from the axis of the rotor 120, that is, the shape of the mounting groove 121 is approximately V-shaped, and a permanent magnet 130 is installed in both the first segment 124 and the second segment 125, thereby improving the magnetizing effect of the permanent magnet 130 and increasing the utilization rate of the permanent magnet 130.

[0044] Furthermore, a demagnetizing area 126 is provided between the first segment 124 and the second segment 125, allowing the two permanent magnets 130 to be arranged relatively apart. Specifically, the demagnetizing area 126 can separate the permanent magnets 130, thereby preventing the permanent magnets 130 in the same mounting groove 121 from contacting and interfering with each other, thus improving the demagnetizing resistance of the permanent magnets 130. Combining the shape of the permanent magnets 130 and the shape of the mounting groove 121, the demagnetizing area 126 is generally triangular. In this embodiment, the minimum distance between the two permanent magnets 130 is approximately 0.1 mm.

[0045] In one embodiment, the residual magnetism of the permanent magnet 130 is Br, and Br ≥ 1.3T. Specifically, to improve the stability of the motor and reduce the phenomenon of the motor failing to function properly due to the disappearance of the residual magnetism of the permanent magnet 130, the residual magnetism of the permanent magnet 130 at 20°C is required to be Br. Preferably, Br ≥ 1.3T, thereby improving the stability of the motor and improving its performance.

[0046] The present invention also proposes a compressor, which includes a motor. The specific structure of the motor is as described in the above embodiments. Since the compressor adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0047] The present invention also proposes a refrigeration device, which includes a compressor. The specific structure of the compressor is as described in the above embodiments. Since the refrigeration device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0048] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An electric motor, characterized in that, include: The stator includes a plurality of spaced stator teeth, each stator tooth having a toothed shoe at one end facing the axis of the stator; The rotor has multiple mounting slots arranged at intervals along its circumference. Permanent magnets are mounted in the mounting slots. Each mounting slot has a magnetic barrier slot at both ends, and both magnetic barrier slots extend toward the d-axis. The angle between the lines connecting the two ends of the two magnetic barrier slots extending toward each other and the center of the rotor is θ1. The angle between the lines connecting the two ends of the toothed shoe and the center of the rotor is θ2. Then, |θ1-θ2| < a preset angle. The tooth width of the stator tooth is bt, the inner diameter of the stator is D, and the residual magnetism of the permanent magnet is Br. Then, |bt-Br*θ1*D*π / 865| < 0.

5.

2. The motor as described in claim 1, characterized in that, The preset angle is less than or equal to 2°.

3. The motor as described in claim 1, characterized in that, The stator has Q stator teeth, and the rotor has 2P mounting slots, where Q=12 and 2P=8.

4. The motor as described in claim 3, characterized in that, The width of the permanent magnet is bM, and the inner diameter of the stator is D, then 0.7 < 4P*bM / (D*π) < 0.

78.

5. The motor as described in claim 4, characterized in that, 4P*bM / (D*π)=0.

75.

6. The motor as described in claim 1, characterized in that, The magnetic barrier groove also extends in a direction away from the d-axis.

7. The motor as described in claim 1, characterized in that, The mounting groove includes a first section and a second section that are connected and set at an angle. The opening of the angle formed by the first section and the second section is located away from the rotor shaft center. A permanent magnet is installed in each of the first section and the second section.

8. The motor as described in claim 7, characterized in that, A demagnetizing zone is provided between the first segment and the second segment, so that the two permanent magnets are arranged at a relative interval.

9. The motor as described in claim 1, characterized in that, The residual magnetism of the permanent magnet is Br, and Br≥1.3T.

10. A compressor, characterized in that, Includes the motor as described in any one of claims 1 to 9.

11. A refrigeration device, characterized in that, Includes the compressor as described in claim 10.

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