A low-harmonic surface-mount motor rotor, permanent magnet motor and compressor

Abstract

This invention provides a low-harmonic surface-mount motor rotor, a permanent magnet motor, and a compressor, relating to the field of compressor motor technology. The low-harmonic surface-mount motor rotor of this invention, applied to the rotor of a permanent magnet motor and then to a compressor, employs a five-segment symmetrical design on the outer end face of the magnet body: four straight segments with different inclination angles and one arc segment. This reshapes the external magnetic field lines, resulting in a smoother five-segment transition, which facilitates sinusoidal back EMF. This maximizes the amplitude of the fundamental no-load back EMF while reducing harmonic content, increasing torque constant, reducing copper losses, and improving motor performance. Furthermore, the sinusoidal design reduces cogging torque and torque pulsation, improves control accuracy, and decreases radial electromagnetic force, thereby reducing noise and vibration levels.

Description

Technical Field

[0001] This utility model relates to the field of compressor motor technology, specifically to a low-harmonic surface-mount motor rotor, a permanent magnet motor, and a compressor. Background Technology

[0002] With the revision of refrigerator energy consumption standards, the market and consumers are increasingly demanding higher energy efficiency and noise levels from refrigerators. For inverter refrigerator compressors, the back EMF amplitude and harmonic content of the motor have a certain impact on performance and noise vibration. Therefore, rotor structure design is particularly important when designing permanent magnet motors. For surface-mounted rotors, it is usually necessary to optimize the dimensions of the outer arc surface structure of the magnet facing the air gap to ensure sinusoidal back EMF.

[0003] Currently, the design of surface-mounted rotors has the following problems:

[0004] 1. The magnet adopts an eccentric design (pole arc coefficient + eccentricity). This method can effectively improve the sinusoidal back EMF, but its effective value is reduced. Moreover, the larger the eccentricity, the higher the sinusoidality, the lower the fundamental amplitude of the back EMF, and the lower the performance.

[0005] 2. The magnet adopts a three-segment design (polar arc coefficient + outer arc three-segment), with symmetrical straight segments on both sides and a circular arc segment in the middle. This method can ensure the effective amplitude, but the harmonic content is relatively high, which affects the control accuracy and increases vibration. Utility Model Content

[0006] The purpose of this invention is to provide a low-harmonic surface-mount motor rotor, permanent magnet motor and compressor that reduces harmonic content while ensuring back EMF amplitude.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A low-harmonic surface-mount motor rotor, comprising:

[0009] The rotor core has several magnet assembly parts evenly spaced on its circumferential side.

[0010] The plane passing through the rotor core axis is defined as the first plane;

[0011] The magnet body has an inner end face that mates with the outer surface of the magnet body assembly. The two sides of the magnet body are coplanar with the first plane. The cross-section of the outer end face of the magnet body is divided into the first segment, the second segment, the third segment, the fourth segment, and the fifth segment from left to right.

[0012] Among them, the straight line between the midpoint of the third segment and the center of the rotor core cross-section is defined as the centerline;

[0013] The third segment is an arc segment, while the first, second, fourth, and fifth segments are straight line segments. The first and fifth segments are of the same length and are symmetrical about the center line, and the second and fourth segments are of the same length and are symmetrical about the center line.

[0014] Furthermore, the central angles corresponding to the first, second, third, fourth, and fifth segments are a1, b1, c, b2, and a2, respectively, where a1 = a2, b1 = b2, and c:b1:a1 = m:n:1, where 11 ≤ m ≤ 12 and 4 ≤ n ≤ 5.

[0015] The angle between the extension of the rotor core cross-section center to the intersection of the second and third segments and the straight line containing the second segment is d, and the angle between the extension of the rotor core cross-section center to the intersection of the third and fourth segments and the straight line containing the fourth segment is d, where 100°≤d≤108°;

[0016] The angle between the extension of the center of the rotor core cross-section to the intersection of the first and second segments and the straight line containing the first segment is e. The angle between the extension of the center of the rotor core cross-section to the intersection of the fourth and fifth segments and the straight line containing the fifth segment is e. 120°≤e≤140°.

[0017] Furthermore, the polar arc coefficient α = Beta1 / Beta, 0.80 ≤ α ≤ 0.95;

[0018] in,

[0019] Beta1 is the arc length spanned by the magnet;

[0020] Beta is the polar distance.

[0021] Furthermore, the inner end face of the magnet is an arc segment, and the third segment is arranged with the same center as the inner end face of the magnet.

[0022] Furthermore, the magnetic steel body assembly part is configured as a slot structure, with a protruding structure between adjacent slot structures.

[0023] Furthermore, six magnet assembly parts are evenly spaced on the circumferential side of the rotor core.

[0024] A permanent magnet motor, wherein the rotor of the permanent magnet motor is configured as the aforementioned low harmonic surface-mount motor rotor.

[0025] A compressor comprising the aforementioned permanent magnet motor.

[0026] The beneficial technical effects of this utility model are:

[0027] This invention discloses a low-harmonic surface-mount motor rotor, applied to the rotor of a permanent magnet motor and used in a compressor. Through a five-segment symmetrical design on the outer end face of the magnet body—four straight segments with different inclination angles and one arc segment—the external magnetic field lines are reorganized, resulting in a smoother five-segment transition that facilitates sinusoidal back EMF. This maximizes the amplitude of the fundamental no-load back EMF while reducing harmonic content, increasing torque constant, reducing copper losses, and improving motor performance. Furthermore, the sinusoidal design reduces cogging torque and torque pulsation, improves control accuracy, and decreases radial electromagnetic force, thereby reducing noise and vibration levels. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the low harmonic surface-mount motor rotor according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the rotor core structure according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the magnet body in an embodiment of the present invention. Figure 1 ;

[0031] Figure 4 This is a schematic diagram of the structure of the magnet body in an embodiment of the present invention. Figure 2 ;

[0032] Figure 5 This is a schematic diagram of the structure of the magnet body in an embodiment of the present invention. Figure 3 ;

[0033] Figure 6 This is a comparison chart of the back EMF harmonic content of embodiments of this utility model;

[0034] Figure 7 This is a waveform diagram of the back electromotive force in an embodiment of this utility model. Detailed Implementation

[0035] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and the accompanying drawings. Some embodiments of this utility model will be described more fully below with reference to the accompanying drawings, and some, but not all, of these embodiments will be shown. In fact, various embodiments of this utility model can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this utility model to meet applicable legal requirements.

[0036] In the description of this utility model, it should be noted that the terms "inner," "outer," "upper," "lower," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In this embodiment of the invention, a low-harmonic surface-mount motor rotor, a permanent magnet motor, and a compressor are provided. Please refer to [the relevant documentation]. Figures 1 to 7 As shown.

[0038] A low-harmonic surface-mount motor rotor includes a rotor core 1 and a magnet body 2.

[0039] The rotor core 1 has six equally spaced magnet assembly parts on its circumferential side. Each magnet assembly part is a slot structure 11, and a protrusion structure 12 is left between adjacent slot structures 11. The plane passing through the axis of the rotor core 1 is defined as the first plane.

[0040] The inner end face 26 of the magnet body 2 mates with the outer surface of the magnet body assembly part. The outer surface of the slot structure 11 is an arc segment, the inner end face 26 of the magnet body 2 is an arc segment, and the outer surface of the slot structure 11 and the inner end face 26 of the magnet body 2 are arranged at the same center.

[0041] The left and right sides 20 of the magnet body 2 are coplanar with the first plane, and the cross-section of the outer end face of the magnet body 2 from left to right is the first segment 21, the second segment 22, the third segment 23, the fourth segment 24 and the fifth segment 25.

[0042] The straight line between the midpoint of the third segment 23 and the center of the cross-section of the rotor core 1 is defined as the centerline.

[0043] The third segment 23 is an arc segment, and the third segment 23 is arranged with the inner end face 26 of the magnet body 2 at the same center.

[0044] The first segment 21, the second segment 22, the fourth segment 24, and the fifth segment 25 are straight segments. The first segment 21 and the fifth segment 25 have the same length and are symmetrical about the midline. The second segment 22 and the fourth segment 24 have the same length and are symmetrical about the midline.

[0045] Specifically, the central angles corresponding to the first segment 21, the second segment 22, the third segment 23, the fourth segment 24, and the fifth segment 25 are a1, b1, c, b2, and a2, respectively, where a1 = a2, b1 = b2, and c:b1:a1 = m:n:1, where 11 ≤ m ≤ 12 and 4 ≤ n ≤ 5.

[0046] The angle between the extension of the center O of the rotor core 1 cross section to the intersection of the second segment 22 and the third segment 23 and the straight line containing the second segment 22 is d. The angle between the extension of the center O of the rotor core 1 cross section to the intersection of the third segment 23 and the fourth segment 24 and the straight line containing the fourth segment 24 is d. 100°≤d≤108°.

[0047] The angle between the extension of the line from the center O of the rotor core 1 cross section to the intersection of the first segment 21 and the second segment 22 and the line containing the first segment 21 is e. The angle between the extension of the line from the center O of the rotor core 1 cross section to the intersection of the fourth segment 24 and the fifth segment 25 and the line containing the fifth segment 25 is e. 120°≤e≤140°.

[0048] like Figure 1 As shown, the low harmonic surface-mount motor rotor of this embodiment has a pole arc coefficient α = Beta1 / Beta, 0.80 ≤ α ≤ 0.95;

[0049] in,

[0050] Beta1 is the arc length spanned by the magnet;

[0051] Beta is the polar distance.

[0052] like Figure 6 , Figure 7 As shown, the low-harmonic surface-mount motor rotor of this embodiment corresponds to the "five-segment scheme". Compared with the "eccentric scheme" and the "three-segment scheme", the "five-segment scheme" of this embodiment can effectively reduce the content of each harmonic when the back EMF amplitude does not change much.

[0053] A permanent magnet motor includes a stator (not shown in the figure) and a rotor, wherein the rotor of the permanent magnet motor is configured as the low harmonic surface-mount motor rotor described above in this embodiment.

[0054] A compressor, wherein the permanent magnet motor described above in this embodiment is mounted on the cylinder block of the compressor.

[0055] The present invention has been described in detail above with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the low-harmonic surface-mount motor rotor of this invention. This low-harmonic surface-mount motor rotor, applied to the rotor of a permanent magnet motor and used in a compressor, employs a five-segment symmetrical design on the outer end face of the magnet body 2. This design includes four straight segments (segment 21, 22, 24, and 25) with different inclination angles and one arc segment (segment 23), thus reshaping the external magnetic field lines. The five-segment transition is smoother, which is beneficial for sinusoidal back EMF. This maximizes the amplitude of the fundamental no-load back EMF while reducing harmonic content, increasing torque constant, reducing copper loss, and improving motor performance. Furthermore, the sinusoidal design reduces cogging torque and torque pulsation, improves control accuracy, and reduces radial electromagnetic force, thereby reducing noise and vibration levels.

[0056] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A low-harmonic surface-mount motor rotor, characterized in that, include: The rotor core has several magnet assembly parts evenly spaced on its circumferential side. The plane passing through the rotor core axis is defined as the first plane; The magnet body has an inner end face that mates with the outer surface of the magnet body assembly. The two sides of the magnet body are coplanar with the first plane. The cross-section of the outer end face of the magnet body is divided into the first segment, the second segment, the third segment, the fourth segment, and the fifth segment from left to right. The straight line between the midpoint of the third segment and the center of the rotor core cross-section is defined as the centerline. The third segment is an arc segment, while the first, second, fourth, and fifth segments are straight line segments. The first and fifth segments are of the same length and are symmetrical about the center line, and the second and fourth segments are of the same length and are symmetrical about the center line.

2. The low harmonic surface-mount motor rotor according to claim 1, characterized in that, The central angles corresponding to the first, second, third, fourth and fifth segments are a1, b1, c, b2 and a2 respectively, a1=a2, b1=b2, c:b1:a1=m:n:1, where 11≤m≤12, 4≤n≤5; The angle between the extension of the rotor core cross-section center to the intersection of the second and third segments and the straight line containing the second segment is d, and the angle between the extension of the rotor core cross-section center to the intersection of the third and fourth segments and the straight line containing the fourth segment is d, where 100°≤d≤108°; The angle between the extension of the center of the rotor core cross-section to the intersection of the first and second segments and the straight line containing the first segment is e. The angle between the extension of the center of the rotor core cross-section to the intersection of the fourth and fifth segments and the straight line containing the fifth segment is e. 120°≤e≤140°.

3. A low-harmonic surface-mount motor rotor according to claim 1 or 2, characterized in that, The polar arc coefficient α = Beta1 / Beta, 0.80 ≤ α ≤ 0.95; in, Beta1 is the arc length spanned by the magnet; Beta is the polar distance.

4. A low-harmonic surface-mount motor rotor according to claim 1 or 2, characterized in that, The inner end face of the magnet is an arc segment, and the third segment is arranged with the same center as the inner end face of the magnet.

5. A low-harmonic surface-mount motor rotor according to claim 1 or 2, characterized in that, The magnetic steel body assembly part is configured as a slot structure, with a protruding structure between adjacent slot structures.

6. A low-harmonic surface-mount motor rotor according to claim 1 or 2, characterized in that, The rotor core has six magnet assembly parts evenly spaced on its circumferential side.

7. A permanent magnet motor, characterized in that: The rotor of the permanent magnet motor is configured as the low harmonic surface-mount motor rotor as described in any one of claims 1 to 6.

8. A compressor, characterized in that: The compressor includes the permanent magnet motor as described in claim 7.

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