Rotor, electric machine, compressor and refrigeration device

Abstract

The application discloses a rotor, a motor, a compressor and a refrigeration device, and relates to the technical field of refrigeration devices, wherein the rotor comprises a rotor core and a permanent magnet, the rotor core is provided with a plurality of mounting grooves in the circumferential direction thereof, two adjacent mounting grooves are symmetrical about a second center line, an inter-pole air groove is arranged between the two adjacent mounting grooves, and each inter-pole air groove is symmetrical about the second center line. The technical scheme provided by the application effectively reduces the leakage magnetic flux in the rotor core by arranging the inter-pole air groove symmetrical about the second center line between the adjacent mounting grooves of the rotor core and limiting the relationship of the relevant geometric parameters L2, L3, S, R, alpha1, alpha2 and P of the rotor, thereby inhibiting the leakage effect caused by the increase of the pole pair number or the increase of the number of the permanent magnets, and the output capacity of the motor is improved.

Description

Technical Field

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

[0002] In existing permanent magnet synchronous motors, mounting slots are used to install permanent magnets, and there is a serious magnetic leakage phenomenon between adjacent mounting slots. For rotor laminations of the same outer diameter, the more magnetic poles there are, the shorter the magnetic leakage path between the mounting slots, and the easier it is for magnetic leakage to occur, which leads to a decrease in the motor's output capacity. Summary of the Invention

[0003] The main objective of this invention is to provide a rotor, motor, compressor, and refrigeration equipment that effectively reduces leakage flux in the rotor core and suppresses leakage flux effects caused by an increase in the number of pole pairs or permanent magnets, thereby improving the output capability of the motor.

[0004] To achieve the above objectives, the rotor proposed in this invention comprises:

[0005] The rotor core has a first centerline and a second centerline extending radially therein. The rotor core has multiple mounting slots spaced apart circumferentially therein. Two adjacent mounting slots are symmetrical about the second centerline. An inter-pole air slot is provided between two adjacent mounting slots. Each inter-pole air slot is symmetrical about the second centerline. The maximum distance from the inter-pole air slot to the rotor core axis is L1, and the minimum distance is L2. The area of ​​the cross-section of the inter-pole air slot cut by a plane perpendicular to the rotor core axis is S. The mounting slot includes a first slot, a second slot, and a connecting slot. The third slot, the first slot and the third slot are symmetrically arranged about the first center line, and extend from the inner circumference of the rotor core to its outer circumference, with the extension direction inclined away from the first center line. The two ends of the second slot are respectively connected to the ends of the first slot and the third slot near the rotor core axis. The included angle between the first slot and the second slot is α1, and the included angle between the first slot and the third slot is α2. The outer radius of the rotor core is R, and the minimum distance from the mounting slot to the rotor core axis is L3.

[0006] A permanent magnet is embedded in the mounting slot and has 2P magnetic poles formed on the circumference of the rotor core;

[0007] Where, 13.8≤α1×α2×(R-L2) / [(R-L3)×360]≤14.4,

[0008] 6.5≤(R-L2)×α2 / (360 / 2P)≤6.9,

[0009] 2.1≤P×S / (R-L3)≤2.4.

[0010] In one embodiment, R-L1 satisfies: 0.35mm≤R-L1≤0.5mm.

[0011] In one embodiment, the minimum distance from the inter-electrode air slot to the adjacent mounting slot is L4, where L4 satisfies: 0.48≤L4 / (R-L1)≤1.35.

[0012] The present invention also proposes an electric motor, including the aforementioned rotor.

[0013] In one embodiment, the motor further includes a stator, which is sleeved on the outer periphery of the rotor. The stator includes a stator core and a stator winding. The stator core includes a stator yoke and stator teeth. A plurality of stator teeth are spaced apart along the inner periphery of the stator yoke. A stator slot is formed between two adjacent stator teeth. The number of stator slots is Q, where Q satisfies: 15≤Q≤18.

[0014] In one implementation, 10 ≤ 2P ≤ 12.

[0015] In one embodiment, the number of phases of the motor is m, and the number of slots per pole per phase of the motor is q, where q = Q / 2mP, and q satisfies: 0 < q < 1.

[0016] In one embodiment, the greatest common divisor of the number of stator slots Q and the number of rotor poles P satisfies: 5≤GCD(Q, P)≤6.

[0017] The present invention also proposes a compressor, including the aforementioned motor.

[0018] The present invention also proposes a refrigeration device, including the aforementioned compressor.

[0019] The technical solution of this invention effectively suppresses magnetic leakage in high-pole motors by setting symmetrical inter-pole air slots about the second center line between adjacent mounting slots of the rotor core, combined with the specific angle design of the mounting slots and the coordinated design of the geometric parameter relationship of the rotor. By limiting 13.8≤α1×α2×(R-L2) / [(R-L3)×360]≤14.4, the matching of the slot angle and position of the inter-pole air slots with the depth of the permanent magnet is coordinated, effectively suppressing magnetic leakage; by limiting 6.5≤(R-L2)×α2 / (360 / 2P)≤6.9, both magnetic leakage suppression and main magnetic circuit integrity are taken into account; by limiting 2.1≤P×S / (R-L3)≤2.4, the total area of ​​the inter-pole air slots is reasonably enlarged as the number of pole pairs increases, adapting to the design requirements of high-pole motors. In this way, by optimizing the rotor structure and limiting the relationship of relevant parameters, the leakage flux in the rotor core is effectively reduced, the leakage flux effect caused by the increase in the number of pole pairs or permanent magnets is suppressed, thereby improving the output capability of the motor. Attached Figure Description

[0020] 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.

[0021] Figure 1 A schematic diagram of the structure of an embodiment of the motor provided by the present invention;

[0022] Figure 2 A schematic diagram of a rotor embodiment provided by the present invention;

[0023] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0024] Figure 4 This is a bar chart showing the ratio of leakage flux as a function of K1.

[0025] Figure 5 This is a bar graph showing the rate of change of motor output power as a function of K2 under the same current.

[0026] Figure 6 This is a bar chart showing the ratio of leakage flux as a function of K3.

[0027] Explanation of icon numbers:

[0028] 100, Rotor core; 200, Stator core; 110, Mounting slot; 111, First slot; 112, Second slot; 113, Third slot; 120, Interpole air slot; 210, Stator yoke; 220, Stator teeth; 230, Stator slot; q1, First center line; q2, Second center line.

[0029] 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

[0030] 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.

[0031] 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 specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0032] 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. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. 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.

[0033] This invention proposes a rotor.

[0034] Please see Figures 1 to 3In one embodiment of the present invention, the rotor includes a rotor core 100 and a permanent magnet. The rotor core 100 has a first centerline q1 and a second centerline q2 extending radially therein. The rotor core 100 is provided with a plurality of mounting slots 110 spaced apart circumferentially therein. Two adjacent mounting slots 110 are symmetrical about the second centerline q2. An inter-pole air groove 120 is provided between two adjacent mounting slots 110. Each inter-pole air groove 120 is symmetrical about the second centerline q2. The maximum distance from the inter-pole air groove 120 to the axis of the rotor core 100 is L1, and the minimum distance is L2. The area of ​​the cross-section of the inter-pole air groove 120 cut by a plane perpendicular to the axis of the rotor core 100 is S. The mounting slots 110 include a first slot 111, a second slot 112, and a... The third slot 113, the first slot 111, and the third slot 113 are symmetrically arranged about the first center line q1 and extend from the inner circumference of the rotor core 100 to its outer circumference, with the extension direction inclined away from the first center line q1. The two ends of the second slot 112 are respectively connected to the ends of the first slot 111 and the third slot 113 near the axis of the rotor core 100. The included angle between the first slot 111 and the second slot 112 is α1, and the included angle between the first slot 111 and the third slot 113 is α2. The outer circle radius of the rotor core 100 is R, and the minimum distance from the mounting slot 110 to the axis of the rotor core 100 is L3. The permanent magnet is embedded in the mounting slot 110 and forms 2P magnetic poles in the circumferential direction of the rotor core 100.

[0035] Where, 13.8≤α1×α2×(R-L2) / [(R-L3)×360]≤14.4,

[0036] 6.5≤(R-L2)×α2 / (360 / 2P)≤6.9,

[0037] 2.1≤P×S / (R-L3)≤2.4.

[0038] Specifically, the rotor includes a rotor core 100 and permanent magnets embedded therein. The rotor core 100 has 2P magnetic poles (P being the number of pole pairs) along its circumference, and each magnetic pole corresponds to a mounting slot 110 for mounting the permanent magnet. A first center line q1 and a second center line q2 serve as geometric reference lines for the rotor core 100, extending radially along the rotor core 100, respectively. The first center line q1 is the axis of symmetry of the main magnetic flux of any magnetic pole, used to define the symmetry reference of the mounting slot 110; the second center line q2 is the center line of the magnetic bridge between two adjacent magnetic poles, i.e., the axis of symmetry of the inter-pole region, used to define the symmetrical arrangement of the inter-pole air slots 120.

[0039] Each mounting slot 110 includes a first slot 111, a second slot 112, and a third slot 113. The mounting slot 110 has a U-shaped structure, which facilitates the stable installation of the permanent magnet and guides the main magnetic flux along a radial path. The first slot 111 and the third slot 113 are symmetrical about the first center line q1 and extend from the inner circumference of the rotor core 100 to its outer circumference, with the extension direction inclined away from the first center line q1, forming an outwardly flared structure. This helps improve the symmetry of the magnetic field distribution and reduce local magnetic saturation. The second slot 112 serves as a connecting channel between the first slot 111 and the third slot 113. Its position is closer to the axis of the rotor core 100 than the first slot 111 and the third slot 113. The magnetic path length and magnetic reluctance are shorter in the area near the second slot 112. The second slot 112 effectively widens the initial path of magnetic flux from the permanent magnet to the air gap, which helps to evenly distribute the magnetic flux to the first slot 111 and the third slot 113 on both sides, avoids excessive concentration of magnetic flux, thereby reducing local magnetic saturation and improving magnetic energy utilization.

[0040] An inter-pole air groove 120 is provided between two adjacent mounting slots 110. The inter-pole air groove 120 is a non-magnetic area used to cut off or extend the leakage magnetic path, thereby suppressing leakage magnetic field between adjacent magnetic poles. Each inter-pole air groove 120 is symmetrically arranged about the second center line q2. Its cross-sectional area (the cross-section obtained by the plane perpendicular to the axis of the rotor core 100) is denoted as S, which represents the size of the space occupied by the inter-pole air groove 120 in the radial plane, and directly affects its ability to block leakage magnetic field.

[0041] L1 is the maximum radial distance from the inter-pole air slot 120 to the axis of the rotor core 100, that is, the distance from the point in the inter-pole air slot 120 closest to the edge of the rotor core 100 to the axis of the rotor core 100. L1 can be measured using a tool microscope or image measuring instrument, with the center of the rotor core 100 as a reference. After clearly imaging the outline of the inter-pole air slot 120 in the instrument, locate the point on the outline farthest from the center, and directly measure the radial distance from that point to the center. The measured value is L1.

[0042] L2 is the minimum radial distance from the interpole air slot 120 to the axis of the rotor core 100, that is, the distance from the point of the interpole air slot 120 closest to the rotor center to the axis of the rotor core 100. L2 can be measured using a tool microscope or image measuring instrument, with the center of the rotor core 100 as a reference. After clearly imaging the outline of the interpole air slot 120 in the instrument, locate the point on the outline closest to the center, and directly measure the radial distance from that point to the center. The measured value is L2.

[0043] L3 is the minimum radial distance from the mounting slot 110 to the axis of the rotor core 100, that is, the minimum distance from the side of the second slot 112 closest to the axis of the rotor core 100 to the axis of the rotor core 100. L3 can be measured using a tool microscope or image measuring instrument, with the center of the rotor core 100 as the reference. After clearly imaging the outline of the mounting slot 110 in the instrument, locate the point on the side of the second slot 112 closest to the axis of the rotor core 100 that is closest to the center, and directly measure the radial distance from that point to the center. The measured value is L3.

[0044] R is the outer radius of the rotor core 100, which is the maximum distance from the outer edge of the rotor core 100 to its axis. R can be measured using a high-precision digital micrometer or a three-dimensional coordinate measuring machine. For example, when using a micrometer, after cleaning the outer circumference of the rotor core 100, gently clamp it between the anvil and the micrometer screw of the micrometer. Measure at least three points evenly distributed around the circumference, record the readings, and calculate the average value. This average value is the rotor outer diameter. Divide it by 2 to obtain the radius R.

[0045] S is the cross-sectional area of ​​a single inter-electrode air slot 120. The method for measuring S is as follows: A two-dimensional image measuring instrument can be used. The rotor lamination is placed flat on the measuring table, and the focus is adjusted to make its outline clear. The measuring instrument lens then captures the complete closed outline of an inter-electrode air slot 120. Subsequently, the "area" measurement function in the software is used to plot points along the inner wall outline of the air slot or to perform image recognition. The software will automatically calculate the area of ​​the closed outline, and this area value is S.

[0046] α1 is the angle between the first slot 111 and the second slot 112. α1 can be measured using a tool microscope or projector. Determine the extension line of the side of the first slot 111 closest to the first center line q1, and the extension line of the side of the second slot 112 closest to the edge of the rotor core 100. Find the actual intersection point of these two extension lines, and then directly measure the smaller angle between the two extension lines at that intersection point. This angle value is α1.

[0047] The second slot 112 has intersection points with the first slot 111 and the third slot 113 on one side near the edge of the rotor core 100. The positions of the two intersection points on the rotor core 100 remain unchanged. The size of α1 is designed by inclining the first slot 111 and the third slot 113 to different degrees. The larger α1 is, the closer the first slot 111 and the third slot 113 are to coinciding with the second slot 112, and the smaller the space between the poles of the two adjacent mounting slots 110. The smaller α1 is, the closer the first slot 111 and the third slot 113 are to being parallel, and the larger the space between the poles.

[0048] α2 is the angle between the first slot 111 and the third slot 113. α2 can be measured using a tool microscope or projector. Determine the extension lines of the sides of the first slot 111 and the third slot 113 closest to the first center line q1, find the actual intersection point of these two extension lines, and then directly measure the angle between the two extension lines at that intersection point. This angle value is α2.

[0049] The ends of the first slot 111 and the third slot 113 furthest from the second slot 112 each have a first endpoint close to the first center line q1. The positions of the first endpoints of the first slot 111 and the third slot 113 remain unchanged, and the width of the second slot 112 remains unchanged. By designing the position of the second slot 112 on the first center line q1, the size of α2 can be designed. The larger α2 is, the closer the second slot 112 is to the outer edge of the rotor core 100, which helps to enhance the air gap magnetic flux density, but at the same time, it also compresses the space of the inter-pole air slot 120; the smaller α2 is, the closer the second slot 112 is to the axis of the rotor core 100.

[0050] P is the number of pole pairs, which can be obtained by counting directly. Directly observe the total number of permanent magnets embedded in the rotor core in 100 circumferences. This total number is the total number of poles, 2P. Therefore, the number of pole pairs P = half the total number of permanent magnets.

[0051] Let K1 = α1 × α2 × (R - L2) / [(R - L3) × 360], where K1 is a dimensionless ratio reflecting the proportional relationship between the circumferential expansion of the mounting groove 110, the radial position of the inter-pole air groove 120, and the installation depth of the permanent magnet. Here, α1 and α2 reflect the circumferential expansion of the mounting groove 110, (R - L2) reflects the radial position of the inter-pole air groove 120, and (R - L3) reflects the installation depth of the permanent magnet.

[0052] When α1 is small, the inter-pole region is more open, which is conducive to arranging a larger inter-pole air slot 120 to reduce magnetic leakage. While increasing α2 is beneficial to improving the efficiency of the external magnetic circuit, it will encroach on the inter-pole space and is not conducive to the arrangement of the inter-pole air slot 120. At the same time, if the size of the inter-pole air slot 120 and the mounting slot 110 is too large and the position is too close to the axis of the rotor core 100, it will reduce the structural strength of the rotor core 100, thereby affecting the output power of the motor.

[0053] By restricting K1, the product of α1 and α2 is normalized and coordinated with the position of the air slot and the installation depth of the permanent magnet in the radial direction of the rotor core 100. This ensures that while increasing the main magnetic flux and guaranteeing the structural strength of the rotor, the leakage magnetic flux in the rotor core 100 is reduced, and the leakage magnetic effect caused by the increase in the number of pole pairs or the increase in the number of permanent magnets is suppressed, thereby improving the output capacity of the motor.

[0054] Please refer to Table 1 and Figure 4Table 1 shows the relationship between the leakage flux ratio and K1. Figure 4 This is a bar chart showing the ratio of leakage flux as a function of K1.

[0055] Table 1: Relationship between leakage flux ratio and K1

[0056]

[0057] From Table 1 and Appendix Figure 4 It can be seen that as K1 increases from 13.6 to 14.6, the leakage flux ratio shows a trend of first decreasing and then increasing.

[0058] When K1 < 13.8, the design parameter combination of the inter-pole air slot 120 (such as α1 being too small, α2 being too small, or L2 being too large, resulting in an excessively shallow air slot) fails to achieve the optimal state. The "magnetic resistance" of the inter-pole air slot 120 is insufficient to effectively block the leakage magnetic path between adjacent magnetic poles, and the leakage magnetic flux can still flow through a relatively short ferromagnetic path, resulting in a high leakage magnetic ratio. At this time, although the main magnetic flux path may be relatively concentrated, the leakage magnetic control is insufficient, limiting the improvement of motor efficiency.

[0059] When K1 > 14.4, the leakage flux ratio begins to rise again as K1 continues to increase. The design of the inter-pole air slot 120 may be too close to the rotor center, i.e., L2 is too small, resulting in an excessively deep and large inter-pole air slot 120. An excessively large inter-pole air slot 120 reduces the magnetic field area of ​​the rotor yoke, potentially weakening the rotor's mechanical structural strength. Simultaneously, excessively pursuing the blocking of leakage flux paths may, to some extent, affect the smoothness of the main magnetic flux path, or occupy space that could be used to arrange permanent magnets, thus leading to a decrease in overall performance. Therefore, the leakage flux ratio increases instead of decreasing.

[0060] When K1 is between 13.8 and 14.4, the leakage flux ratio decreases significantly and remains at a low level. Within this range, the combination of rotor geometric parameters achieves an optimal balance, allowing the inter-pole air slot 120 to most effectively increase the magnetic reluctance of the leakage flux path. At this time, α1 is small, the inter-pole space is relatively open, and it is convenient to arrange a larger-sized air slot; α2 is reasonably increased, so that the permanent magnet is closer to the outer edge, enhancing the air gap magnetic field without excessively compressing the inter-pole space; the positions of the inter-pole air slot 120 and the mounting slot 110 on the rotor core 100 are relatively close to the axis of the rotor core 100, and the inter-pole air slot 120 has sufficient radial length, forming a long and high-resistance leakage flux path while maintaining good coordination with the main magnetic circuit. Thus, while ensuring the motor output power, the magnetic reluctance of the leakage flux path is significantly improved, thereby suppressing leakage flux to the maximum extent; at the same time, the rotor core 100 still has good structural strength.

[0061] Let K2 = (R - L2) × α2 / (360 / 2P), where K2 is a dimensionless ratio. (R - L2) represents the radial position of the inter-pole air slot 120; α2 is the circumferential angle of the mounting slot 110, affecting the magnetic pole coverage angle; (360 / 2P) is the theoretical circumferential angle occupied by each magnetic pole; K2 reflects the ratio of the combined radial and circumferential dimensions of the inter-pole air slot 120 to the angle of a single magnetic pole. By limiting K2 to between 6.5 and 6.9, it is beneficial to optimize the size of the inter-pole air slot 120, avoiding the situation where the inter-pole air slot 120 is too small, resulting in insufficient magnetic isolation, or too large, resulting in compression of the magnetic pole area and weakening of the main magnetic flux.

[0062] Please refer to Table 2 and Figure 5 Table 2 shows the relationship between the rate of change of motor output power and K2 under the same current. Figure 5 This is a bar graph showing the rate of change of motor output power as a function of K2 under the same current.

[0063] Table 2: Relationship between the rate of change of motor output power and K2 under the same current

[0064]

[0065] Figure 5 The vertical axis represents the rate of change of motor output power under the same current, where the output power of the motor at K2=6.3 is used as the optimization benchmark. Figure 5 The table shows the variation of motor output power relative to a reference value under different K2 values. (See Table 2 and Appendix...) Figure 5 It can be seen that as K2 increases from 6.1 to 7.3, the rate of change of motor output power under the same current shows a trend of first increasing and then decreasing.

[0066] As the K2 value increases from 6.1 to 6.7, the equivalent size of the inter-pole air slot 120 (determined by the depth (R-L2) and the pole opening angle α2) relative to the width of a pole continuously increases. During this stage, the inter-pole air slot 120 effectively increases the magnetic reluctance of the leakage magnetic path, resulting in a continuous improvement in the motor's flux utilization and output torque. With the same input current, the output power steadily increases.

[0067] When the K2 value exceeds 6.7 and continues to increase, the rate of change of motor output power begins to decrease. An excessively large K2 value means that the inter-pole air slot 120 may be too deep or too large, which begins to produce side effects. For example, an excessively large slot will not only weaken the mechanical strength of the rotor yoke, but also encroach on the path cross-section of the main magnetic flux, increase the magnetic reluctance of the main magnetic circuit, and cause a decrease in the total effective magnetic flux generated by the permanent magnet.

[0068] When the K2 value is between 6.5 and 6.9, the rate of change of motor output power exceeds the reference value. At this point, the leakage flux suppression effect and the smoothness of the main magnetic flux path are well balanced. The size of the inter-pole air slot 120 can suppress leakage flux to the greatest extent without having a significant negative impact on the main magnetic circuit and rotor structural strength.

[0069] Let K3 = P × S / (R - L3), where K3 is a dimensionless ratio. K3 represents the ratio of the total cross-sectional area of ​​the inter-pole air slots 120 configured for each pair of magnetic poles to the depth of the permanent magnet, reflecting the total inter-pole magnetic reluctance provided per unit length for a given main magnetic flux path length. (P × S) represents the total magnetic reluctance contribution of all inter-pole air slots 120. As the number of pole pairs P increases, the leakage magnetic tendency intensifies, requiring a corresponding increase in the cross-sectional area S of the inter-pole air slots 120 to compensate. The larger the cross-sectional area S of each inter-pole air slot 120, the higher the overall magnetic reluctance, but this also leads to a decrease in the structural strength of the rotor. (R - L3) reflects the radial position of the permanent magnet, i.e., the radial embedment depth of the permanent magnet. If (R - L3) is too large, the permanent magnet will be far from the axis of the rotor core 100, which may reduce the magnetic flux density or weaken the structural strength; if it is too small, the main magnetic flux path will be short and prone to saturation.

[0070] Please refer to Table 3 and Figure 6 Table 3 shows the relationship between the leakage flux ratio and K3. Figure 6 This is a bar chart showing the ratio of leakage flux as a function of K3.

[0071] Table 3: Relationship between leakage flux ratio and K3

[0072]

[0073] From Table 3 and Appendix Figure 6 It can be seen that as K3 increases from 1.7 to 2.6, the leakage flux ratio shows a trend of first decreasing and then increasing.

[0074] When K3 < 2.1, it indicates that the cross-sectional area of ​​the inter-electrode air slot 120 is insufficient or the number of poles is too small; if P is large and S is small, that is, each inter-electrode air slot 120 is too narrow, resulting in low magnetic reluctance and severe magnetic leakage; or R L3 is relatively large, meaning the depth of the mounting slot 110 is relatively large. Although the main magnetic flux is strong, there is a lack of sufficient inter-pole air slot 120 to block it, resulting in insufficient inter-pole isolation capability and an inability to effectively suppress the increased magnetic leakage caused by multipolarization.

[0075] When K3 > 2.4, it indicates that the cross-sectional area of ​​the inter-pole air slot 120 is too large or the main magnetic flux path is too short; if S is too large, the air slot is too wide, which leads to a reduction in the permanent magnet region, and consequently a weakening of the main magnetic flux; or R If L3 is too small, that is, the depth of the mounting slot 110 is too shallow, the magnetic circuit is short and easily saturated. This not only increases local eddy current losses, but also causes the bridge part of the rotor core 100 to become thinner due to the excessively large inter-pole air slot 120, resulting in a decrease in mechanical strength and an increase in processing difficulty.

[0076] When K3 is between 2.1 and 2.4, the leakage flux ratio is below 2.76%. Each magnetic pole is allocated a sufficiently large air slot area to form a high-resistivity leakage flux path; the leakage flux is forced to take a longer path, and the magnetic resistance increases significantly, thereby effectively suppressing leakage flux; at the same time, the main flux path is unobstructed, the air gap magnetic flux density is stable, and the rotor core 100 maintains good structural strength.

[0077] The technical solution of this invention effectively suppresses magnetic leakage in high-pole motors by setting inter-pole air slots 120 symmetrical about the second center line q2 between adjacent mounting slots 110 of the rotor core 100, and by combining the specific angle design of the mounting slots 110 with the coordinated design of the geometric parameter relationship of the rotor. By limiting 13.8≤α1×α2×(R-L2) / [(R-L3)×360]≤14.4, the matching of the slot angle and position of the inter-pole air slot 120 with the depth of the permanent magnet is coordinated, effectively suppressing magnetic leakage; by limiting 6.5≤(R-L2)×α2 / (360 / 2P)≤6.9, both magnetic leakage suppression and main magnetic circuit integrity are taken into account; by limiting 2.1≤P×S / (R-L3)≤2.4, the total area of ​​the inter-pole air slot 120 is reasonably enlarged as the number of pole pairs increases, adapting to the design requirements of high-pole motors. In this way, by optimizing the rotor structure and limiting the relationship of relevant parameters, the leakage flux in the rotor core 100 is effectively reduced, the leakage flux effect caused by the increase in the number of pole pairs or the increase in the number of permanent magnets is suppressed, thereby improving the output capability of the motor.

[0078] In one embodiment, R-L1 satisfies: 0.35mm≤R-L1≤0.5mm.

[0079] R-L1 represents the radial thickness from the outermost edge of the inter-pole air slot 120 to the outer surface of the rotor, i.e., the thickness of the bridge portion of the material between the inter-pole air slot 120 and the outer edge of the rotor. When R-L1 < 0.35 mm, the bridge portion is too thin, which may cause the rotor to undergo mechanical deformation or even breakage due to centrifugal force during high-speed rotation, affecting the safety and reliability of motor operation; at the same time, an excessively thin bridge portion is also difficult to effectively support the permanent magnet, increasing the risk of demagnetization. Conversely, when R-L1 > 0.5 mm, the bridge portion is too thick. Although it enhances mechanical strength, it will significantly compress the radial space of the inter-pole air slot 120, limiting its outward extension ability, weakening its effect of blocking leakage flux, leading to increased leakage flux and reduced magnetic circuit efficiency. By limiting the R-L1 to 0.5mm, sufficient space can be provided for the inter-pole air slot 120 while ensuring the structural strength of the rotor and the reliability of the permanent magnet installation. This allows the high magnetic reluctance characteristics to be fully utilized to suppress magnetic leakage between adjacent magnetic poles, thus balancing electromagnetic performance optimization and mechanical safety requirements, and improving the overall output capacity and operational stability of the motor.

[0080] In one embodiment, the minimum distance from the inter-pole air slot 120 to the adjacent mounting slot 110 is L4, and L4 satisfies: 0.48≤L4 / (R-L1)≤1.35.

[0081] L4 represents the minimum distance between the edge of the inter-pole air groove 120 and the nearest mounting groove 110 (i.e., the first slot 111 or the third slot 113). The method for measuring L4 is as follows: A dedicated plug gauge or sheet gauge can be used for comparative measurement. Plug gauges of different thicknesses are inserted into the gap between the inter-pole air groove 120 and the mounting groove 110. The thickest gauge sheet that fits snugly with slight resistance is found, and its marked thickness is an approximation of L4. Alternatively, a two-dimensional image measuring instrument or tool microscope can be used to image the rotor laminations, and L4 can be directly calculated using its measurement software.

[0082] L4 directly affects the length of the leakage magnetic path and the magnetic flux density distribution in the magnetic bridge region; R-L1 represents the radial thickness from the outermost edge of the interpole air slot 120 to the outer circular surface of the rotor, and L4 / (R-L1) reflects the relative positional relationship between the interpole air slot 120 and the mounting slot 110, which is used to coordinate the balance between leakage magnetic suppression and structural strength.

[0083] When L4 / (R-L1) < 0.48, it indicates that the inter-pole air slot 120 is too close to the mounting slot 110, resulting in an excessively narrow magnetic bridge. Although this increases the magnetic resistance of the leakage magnetic path, it can easily cause local magnetic saturation, thus reducing the main magnetic flux conduction capacity and potentially weakening the structural strength. When L4 / (R-L1) > 1.35, the inter-pole air slot 120 is too far from the mounting slot 110, occupying too much space in the rotor core 100 and compressing the effective magnetic pole area, which is not conducive to the formation of the main magnetic flux. It may also lead to an unreasonable arrangement of the inter-pole air slot 120, and the effect of suppressing leakage magnetic flux will no longer be significantly improved. By limiting 0.48 ≤ L4 / (R-L1) ≤ 1.35, the inter-pole air slot 120 can effectively isolate the leakage magnetic flux between adjacent magnetic poles, extend the leakage magnetic path, and increase the magnetic resistance, while ensuring smooth magnetic circuit and avoiding local saturation. This further enhances the leakage magnetic flux suppression effect and helps improve the uniformity of air gap magnetic flux density, output torque, and overall efficiency of the motor.

[0084] The present invention also proposes an electric motor, which includes a rotor. The specific structure of the rotor is as described in the above embodiments. Since the present motor 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.

[0085] In one implementation, please refer to Figure 1 The motor also includes a stator, which is sleeved on the outer periphery of the rotor. The stator includes a stator core 200 and a stator winding. The stator core 200 includes a stator yoke 210 and stator teeth 220. Multiple stator teeth 220 are spaced along the inner periphery of the stator yoke 210. A stator slot 230 is formed between two adjacent stator teeth 220. The number of stator slots 230 is Q, and Q satisfies: 15≤Q≤18.

[0086] Q represents the number of stator slots 230, which can be directly obtained by counting. The number of stator slots 230 in the motor is limited to 15 ≤ Q ≤ 18, meaning that 15 to 18 stator slots 230 are evenly distributed along the inner circumference of the stator core 200 for housing the stator windings. If Q < 15, the slot spacing of the stator slots 230 is too large, leading to discontinuous changes in air gap magnetic permeability, severe distortion of the back electromotive force waveform, high harmonic content, and a significant increase in vibration and noise. If Q > 18, the slot density of the stator slots 230 is too high, which not only increases the difficulty of the stator core 200 stacking process but may also trigger high-frequency electromagnetic resonance. Simultaneously, the slot leakage inductance increases, affecting motor efficiency and dynamic response. By limiting Q to 15 ≤ Q ≤ 18, good electromagnetic performance can be ensured while optimizing the spatial matching relationship with the rotor inter-pole air slots 120 and mounting slots 110, which is beneficial for achieving higher power density and torque output. By combining the inter-pole air slot 120 and parameter optimization design in the aforementioned rotor structure, electromagnetic interference can be further reduced and the overall performance of the motor can be improved by suppressing leakage flux and improving the utilization rate of main magnetic flux through reasonable slot-pole matching.

[0087] In one implementation, please refer to Figure 1 , 10≤2P≤12.

[0088] The total number of magnetic poles in a permanent magnet synchronous motor is limited to 10 ≤ 2P ≤ 12, meaning the motor can have a 10-pole, 11-pole, or 12-pole structure (P being the number of pole pairs). In permanent magnet synchronous motors, the number of poles affects the spatial distribution frequency of the air gap magnetic field, the back electromotive force waveform, torque density, and cogging torque characteristics. When 2P < 10, the pole pitch is large, the magnetic field changes slowly, resulting in a lower back electromotive force frequency. This limits the motor's output power at the same speed, and a low pole number easily leads to larger torque pulsations and vibration noise. Conversely, when 2P > 12, the pole pitch is too small, and the interaction between the stator teeth and the rotor structure becomes more frequent. While this can improve torque smoothness, it increases rotor core losses, manufacturing difficulty, and high-frequency harmonic content, while also requiring a faster response speed from the controller.

[0089] By limiting 10≤2P≤12, on the one hand, it helps to refine the magnetic field modulation period, making the air gap magnetic flux density distribution more sinusoidal, effectively suppressing low-order harmonics such as the 5th and 7th, and reducing cogging torque and operating noise; on the other hand, it can ensure reasonable slot-pole matching, reduce the risk of harmonic resonance, reduce winding leakage inductance and copper loss, and improve motor efficiency and power density.

[0090] Furthermore, in permanent magnet synchronous motors, the number of stator slots (Q) and rotor poles (P) jointly determine the number of slots per pole per phase, thus affecting the magnetic field modulation effect and winding distribution characteristics. Combining the preferred pole combination of 10 ≤ 2P ≤ 12, a good slot-pole match can be achieved when 15 ≤ Q ≤ 18. For example, Q = 18 and 2P = 12 form an integer-slot winding with good winding symmetry and mature manufacturing process; Q = 15 or 18 and 2P = 10 form a fractional-slot winding, which helps to disperse magnetomotive force harmonics and reduce cogging torque.

[0091] In one embodiment, the number of phases of the motor is m, and the number of slots per pole per phase of the motor is q, where q = Q / 2mP, and q satisfies: 0 < q < 1.

[0092] The motor has m phases, Q stator slots (230 slots), and P pole pairs. The number of slots per pole per phase is defined as q = Q / 2mP, where q satisfies 0 < q < 1. This means the motor uses a fractional-slot winding structure, and the number of slots per pole per phase is less than one slot. The number of slots per pole per phase, q, is one of the core indicators in the motor's electromagnetic design, directly affecting the harmonic content of the air gap magnetomotive force, cogging torque, winding distribution factor, and electromagnetic noise characteristics. When q ≥ 1, it is an integer-slot winding, which has good winding symmetry and is simple to manufacture, but it easily generates strong low-order magnetomotive force harmonics, and the cogging period is fixed in relation to the pole pitch, which is not conducive to harmonic suppression. When 0 < q < 1, it is a typical fractional-slot winding.

[0093] The fractional slot structure allows for a non-common multiple of the stator slot number (230) and rotor pole number to be matched, effectively dispersing the spatial harmonic energy of the air gap magnetic field and preventing the concentrated superposition of harmonics, thereby significantly reducing cogging torque and torque pulsation. Secondly, such windings typically have shorter end lengths, reducing copper losses and improving motor efficiency and power density. Furthermore, the q<1 structure helps achieve more uniform magnetic field modulation, working synergistically with the rotor topology of the inter-pole air slot 120 and multi-segment mounting slot 110 in this invention to further optimize the air gap magnetic flux density waveform, making it closer to a sinusoidal distribution and suppressing the 5th and 7th harmonic components in the back electromotive force. Simultaneously, q>0 ensures that each phase has a conductor participating in operation under each magnetic pole, maintaining basic electromagnetic conversion capability.

[0094] In one embodiment, the greatest common divisor of the number of stator slots 230 Q and the number of rotor poles P satisfies: 5≤GCD(Q, P)≤6.

[0095] In permanent magnet synchronous motors, the relative motion between the stator slots and the rotor poles generates periodic changes in magnetic permeability, whose harmonic characteristics are closely related to the common divisor of Q and P. GCD(Q, P) reflects the minimum repetition period of the electromagnetic interaction between the stator and rotor. When GCD(Q, P) is too small (e.g., 1 or 2), it indicates that the engagement period between the stator slot 230 and the pole is short, the cogging effect repetition frequency is low, and low-order mechanical resonance is easily excited, leading to significant vibration and noise. When GCD(Q, P) is too large (e.g., ≥7), it indicates that the engagement period between the stator slot 230 and the pole is long, which leads to more complex winding design or the introduction of new low-frequency disturbances.

[0096] By limiting 5≤GCD(Q, P)≤6, the motor has a longer and more stable electromagnetic periodic structure, the spatial symmetry of the electromagnetic force wave is enhanced, and the harmonic energy is effectively dispersed, which helps to reduce cogging torque and torque pulsation.

[0097] 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.

[0098] 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.

[0099] The above description is merely an exemplary 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 specification and drawings under the technical 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. A rotor characterized by, The rotor core has a first center line and a second center line extending in a radial direction thereof, and a plurality of mounting slots are spaced apart in a circumferential direction of the rotor core, two adjacent mounting slots are symmetric about the second center line, an inter-pole air slot is arranged between the two adjacent mounting slots, each inter-pole air slot is symmetric about the second center line, a maximum distance of the inter-pole air slot to an axis of the rotor core is L1, a minimum distance of the inter-pole air slot to the axis of the rotor core is L2, an area of a cross section of the inter-pole air slot cut by a plane perpendicular to the axis of the rotor core is S, the mounting slot comprises a first clamping slot, a second clamping slot and a third clamping slot connected in communication, the first clamping slot and the third clamping slot are symmetric about the first center line and extend from an inner circumferential region of the rotor core to an outer circumferential region thereof, and the extending direction is inclined away from the first center line, two ends of the second clamping slot are in communication with one end of the first clamping slot and one end of the third clamping slot close to the axis of the rotor core, an included angle between the first clamping slot and the second clamping slot is α1, and an included angle between the first clamping slot and the third clamping slot is α2; an outer circumferential contour radius of the rotor core is R, and a minimum distance of the mounting slot to the axis of the rotor core is L3; and A permanent magnet is embedded in the mounting slot and forms 2P magnetic poles in the circumferential direction of the rotor core. 13.8≤α1×α2×(R-L2) / [(R-L3)×360]≤14.4, 6.5≤(R-L2)×α2 / (360 / 2P)≤6.9, 2.1≤P×S / (R-L3)≤2.4; α1×α2×(R-L2) / [(R-L3)×360], (R-L2)×α2 / (360 / 2P) and P×S / (R-L3) are all dimensionless. R-L1 satisfies 0.35mm≤R-L1≤0.5mm.

2. The rotor of claim 1, wherein A minimum distance of the inter-pole air slot to the adjacent mounting slot is L4, and L4 satisfies 0.48≤L4 / (R-L1)≤1.

35.

3. The rotor of claim 1, wherein The motor comprises the rotor as claimed in any one of claims 1 to 3.

4. An electric machine characterized by The motor further comprises a stator sleeved on an outer circumferential region of the rotor, the stator comprises a stator core and a stator winding, the stator core comprises a stator yoke and a plurality of stator teeth spaced apart along an inner circumferential region of the stator yoke, and a stator slot is formed between two adjacent stator teeth, and a number of the stator slots is Q, and Q satisfies 15≤Q≤18.

5. The electric machine of claim 4, wherein, A number of phases of the motor is m, and a number of slots per pole per phase of the motor is q, q=Q / 2mP, and q satisfies 0 6. The electric machine of claim 5, wherein, 10≤2P≤12。 7. The electric machine of claim 6, wherein, A greatest common divisor of the number of the stator slots Q and the number of poles P of the rotor satisfies 5≤GCD(Q, P)≤6.

8. The electric machine of claim 6, wherein, The motor comprises the motor as claimed in any one of claims 4 to 8.

9. A compressor characterized by, The compressor comprises the motor as claimed in claim 9.

10. A refrigeration appliance characterized in that, ​

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