Permanent magnet motor and variable frequency scroll compressor

Abstract

The present invention provides a permanent magnet motor and a variable frequency scroll compressor, which relate to the technical field of scroll compressor design and manufacturing. The permanent magnet motor includes a stator core and a rotor core; the stator core includes stator slots uniformly distributed along the circumference, copper windings are embedded in the slots, and a uniformly distributed stator yoke is provided on the outside of each slot bottom. Each stator yoke is provided with an arc-shaped long slot, and a stator tooth is provided between two adjacent stator slots. The tops of the stator teeth are all recessed to form flow grooves; uniformly distributed magnetic steel slots are provided in the rotor core, two identical first magnetic isolation slots are provided between two adjacent magnetic steel slots, magnetic steel is provided in the magnetic steel slot, and two symmetrically distributed second magnetic isolation slots are provided on the top of each magnetic steel. The outer radius Rs1 of the stator core, the inner radius Rs2 of the stator core and the axial length Lis of the stator core in the present invention satisfy: 1.282≤Lis / (Rs1-Rs2)≤2.778, and 34≤Rs1-Rs2≤39mm. It can increase the power density of the motor, reduce costs, improve efficiency, reduce harmonic content and thus suppress torque pulsation.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor design and manufacturing, and more specifically, to a permanent magnet motor and a variable frequency scroll compressor. Background Art

[0002] The variable frequency scroll compressor is equipped with a permanent magnet motor and a high-performance inverter, which can be continuously adjusted within a wide speed range according to different ambient temperatures and load requirements to reduce energy loss caused by frequent starts and stops. In addition, due to its small number of moving parts and simple structure, it also has the advantages of high mechanical efficiency, low failure rate, low mechanical noise, and long life.

[0003] With the continuous upgrading of my country's energy efficiency standards, the surge in demand in the heat pump field, the rapid development of new energy vehicles, the expansion of data centers and cold chains, variable frequency scroll compressors have gradually occupied a higher market share, and variable frequency has become a major trend in the development of scroll compressors.

[0004] Although permanent magnet motors have advantages such as high efficiency, high overload capacity, and a wide speed range, compared with traditional fixed-frequency scroll compressors equipped with asynchronous motors, they have many shortcomings such as high cost, low torque density, and a large number of harmonics in the motor itself that cause high electromagnetic vibration noise. These shortcomings bring technical challenges to the design of permanent magnet motors, and relevant technologies need to be used to address the above-mentioned shortcomings.

[0005] The present invention provides a permanent magnet motor and variable frequency scroll compressor technology to achieve the purposes of increasing the power density of the permanent magnet motor, reducing costs, improving efficiency, reducing harmonic content and thus suppressing torque pulsation. Summary of the Invention

[0006] The variable frequency scroll compressor equipped with a permanent magnet motor proposed above has many shortcomings compared to the traditional fixed frequency scroll compressor equipped with an asynchronous motor, such as high cost, low torque density, and large vibration and noise caused by a large number of harmonics in the motor itself. A permanent magnet motor and a variable frequency scroll compressor are provided. The present invention can increase the power density of the motor, reduce costs, and improve efficiency by limiting the relationship between the inner and outer radius of the stator and the length of the iron core; and by providing arc-shaped long slots on the stator iron core and first and second magnetic isolation slots on the rotor iron core, the no-load back electromotive force waveform can be improved, thereby suppressing torque pulsation and reducing vibration and noise.

[0007] The technical means adopted in the present invention are as follows:

[0008] A permanent magnet motor comprises an external stator core and a rotor core arranged inside the stator core;

[0009] The stator core includes stator slots evenly distributed along the circumference, wherein copper windings of circular enameled wire are embedded in the stator slots. A stator yoke is evenly distributed outside the bottom of each stator slot, and each stator yoke has an arc-shaped long slot. Stator teeth are provided between two adjacent stator slots, and the tops of the stator teeth are all recessed to form flow grooves.

[0010] The rotor core is provided with uniformly distributed magnetic steel slots, two identical first magnetic isolation slots are provided between two adjacent magnetic steel slots, magnetic steels with alternating north and south poles are provided in the magnetic steel slots, and two symmetrically distributed second magnetic isolation slots are provided on the top of each magnetic steel;

[0011] A first magnetic bridge and a second magnetic bridge are provided between the top of the magnetic steel slot and the second magnetic isolation slot and the outer circle of the rotor core;

[0012] The outer radius of the stator core is Rs1, the inner radius of the stator core is Rs2, and the axial length of the stator core is Lis; wherein Rs1, Rs2 and Lis satisfy: 1.282≤Lis / (Rs1-Rs2)≤2.778, and 34≤Rs1-Rs2≤39mm.

[0013] Furthermore, the number of stator slots is Q, the copper windings of circular enameled wire embedded in the stator slots constitute a three-phase symmetrical winding, the number of magnetic steel slots distributed in the rotor core is p, wherein Q and p satisfy: p / Q=2 / 3.

[0014] Furthermore, the outer circle of the rotor core is a full circle, the center of which is at the center of the rotating shaft; the outer radius of the rotor core is Rr1, and satisfies: 0.45mm≤Rs2-Rr1≤1mm;

[0015] The axial length of the rotor core is Lir, and satisfies: 0≤Lis-Lir≤2(Rs2-Rr1), where 50mm≤Lis≤100mm.

[0016] Furthermore, the stator slot bottom radius is Rs3, wherein Rs3 and Rs1 satisfy the following relationship: 8.3 mm ≤ Rs1 - Rs3 ≤ 14.6 mm.

[0017] Furthermore, the depth of the through-flow groove is hs1, and satisfies, 0<hs1≤Rs1-Rs3; the stator tooth width is ws1, and satisfies 12.2mm≤ws1≤17.4mm; the through-flow groove width is ws2, the through-flow groove central angle is θ3, and satisfies: ws1≤ws2≤2 Rs1 cos(θ3 / 2); where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1))≤θ3≤(360° / Q)-θ1.

[0018] Furthermore, the central angle of the arc-shaped long slot is θ1, and the central angle of the stator slot bottom is θ2, where θ1≤θ2; the inner radius of the arc-shaped long slot is Rs4, and the outer radius of the arc-shaped long slot is Rs5, and they satisfy Rs1-hs1<Rs4<Rs5<Rs1; the width of the arc-shaped long slot is hs2, satisfying 1.2mm≤hs2≤2mm; where hs2=Rs5-Rs4.

[0019] Furthermore, after magnetization, the magnetic field direction of the magnets uniformly distributed along the circumference is perpendicular to the long side of the magnets, and the length of the long side of the magnets is hpm; the length of the short side of the magnets is wpm, satisfying 1.8mm≤wpm≤3.5mm; the width of the first magnetic isolation groove is wg1, satisfying 1.2mm≤wg1≤2.5mm; the length of the first magnetic isolation groove is hg1, satisfying wg1<hg1≤wpm; the distance between the first magnetic isolation groove and the magnetic steel groove is wb1, the distance between the two first magnetic isolation grooves is wb2, and the distance between wb1 and wb2 satisfies: 0.45mm≤wb1≤wb2≤1.5mm.

[0020] Furthermore, the vertical distance between the first magnetic isolation groove and the outer circle of the rotor is t0, the thickness of the first magnetic bridge is t1, the thickness of the second magnetic bridge is t2, and the following conditions are satisfied: 0.5mm≤t0≤t1≤1.5mm, wherein t1=t2.

[0021] Furthermore, the width of the second magnetic isolation groove is wg2, satisfying 0.8mm≤wg2≤1.8mm; the longest side length of the second magnetic isolation groove is hg2, satisfying wg2≤hg2≤2.2mm; the distance between the second magnetic isolation groove and the magnetic steel groove is wb3, satisfying 0.45mm≤wb3≤1.5mm.

[0022] The present invention also provides a variable frequency scroll compressor, comprising the permanent magnet motor.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. By limiting the outer radius Rs1 of the stator core, the inner radius Rs2 of the stator core, and the axial length Lis of the stator core to meet the following condition: 1.282≤Lis / (Rs1-Rs2)≤2.778, the power density of the motor can be increased, thereby reducing the cost of electromagnetic materials. In addition, the copper and iron losses of the motor can be reasonably distributed, thereby improving the efficiency of the motor.

[0025] 2. By introducing and properly arranging the first and second magnetic isolation slots and arc-shaped slots in the rotor core, certain subharmonics can be reduced without compromising power density, thereby increasing the sinusoidality of the back EMF waveform, suppressing torque ripple, and minimizing the effects of vibration and noise. Furthermore, the introduction of the arc-shaped slots increases the refrigerant flow area within the compressor, reducing stator core temperature rise and increasing efficiency.

[0026] 3. Based on the magnetic circuit characteristics that satisfy the relationship p / Q=2 / 3 between the number of stator slots Q and the number of magnetic steel slots p distributed in the rotor core, flow slots are opened at specific positions of the stator core to provide a path for the circulation of refrigerant, further reducing the temperature rise of the motor and increasing the efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 Schematic diagram of the structure of the permanent magnet motor of the present invention.

[0029] Figure 2 It is a schematic diagram of the stator core structure in the present invention.

[0030] Figure 3 This is a schematic diagram of the rotor core structure in the present invention.

[0031] Figure 4 It is a partial enlarged view of the rotor structure schematic diagram in the present invention.

[0032] Figure 5 The figure shows a power density comparison between the permanent magnet motor of the present invention and the prior art.

[0033] Figure 6 The figure shows a cost comparison between the permanent magnet motor of the present invention and the prior art.

[0034] Figure 7 The following are efficiency diagrams of the permanent magnet motor using the present invention under different working conditions.

[0035] Figure 8 The figure is a comparison of the no-load back electromotive force harmonics of the permanent magnet motor of the present invention and the prior art.

[0036] Figure 9 The figure is a comparison of the no-load back EMF harmonic distortion rate of the permanent magnet motor of the present invention and the prior art.

[0037] Figure 10The figure is a comparison diagram of the electromagnetic torque waveforms of the permanent magnet motor using the present invention and the prior art.

[0038] In the figure: 1. Permanent magnet motor; 2. Stator core; 3. Stator slots; 4. Copper winding; 5. Stator yoke; 6. Arc-shaped long slots; 7. Stator teeth; 8. Current flow slots; 9. Rotor core; 10. Magnetic steel slots; 11. First magnetic isolation slots; 12. Magnetic steel; 13. Second magnetic isolation slots; 14. First magnetic bridge; 15. Second magnetic bridge. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0043] like Figure 1-4 As shown, the present invention provides a permanent magnet motor, which includes a stator core 2 outside and a rotor core 9 arranged inside the stator core 2; the stator core 2 includes stator slots 3 evenly distributed along the circumference, and a copper winding 4 of a circular enameled wire is embedded in the stator slots 3. A stator yoke 5 is evenly distributed on the bottom and outside of each stator slot 3. Each stator yoke 5 has an arc-shaped long slot 6. A stator tooth 7 is provided between two adjacent stator slots 3. The top of the stator tooth 7 is recessed to form a flow groove 8; the rotor core 9 is evenly provided with a stator yoke 5. The magnetic steel slots 10 are distributed, and two identical first magnetic isolation slots 11 are provided between adjacent magnetic steel slots 10. The magnetic steel slots 10 are provided with magnetic steels 12 with alternating north and south poles, and two second magnetic isolation slots 13 are symmetrically distributed on the top of each magnetic steel 12; a first magnetic bridge 14 and a second magnetic bridge 15 are provided between the tops of the magnetic steel slots 10 and the second magnetic isolation slots 13 and the outer circle of the rotor core 9; wherein the outer radius of the stator core 2 is Rs1, the inner radius of the stator core 2 is Rs2, and the axial length of the stator core 2 is Lis, and Rs1, Rs2 and Lis satisfy: 1.282≤Lis / (Rs1-Rs2)≤2.778, and 34≤Rs1-Rs2≤39mm, and the constraints of the relationship between the three are obtained based on the requirements of the compressor displacement for the motor, the reasonable design of the electrical load and the magnetic load, the limitation of the compressor shell volume, the cost and other comprehensive factors. It can increase the power density of the motor, reduce costs, improve efficiency, reduce harmonic content and thus suppress torque pulsation.

[0044] Preferably, the number of stator slots 3 is Q, where the round enameled wire embedded in the stator slots 3 forms a three-phase symmetrical winding 4. The number p of magnets 12 distributed around the rotor core 9 satisfies p / Q = 2 / 3, forming a concentrated winding. The three-phase symmetrical winding 4 can be mechanically wound or concentratedly embedded to reduce the end length of the winding 4 and increase efficiency. In this embodiment, the number of stator slots 3 is 9, and the number of magnets 12 is 6, achieving the condition of p / Q = 2 / 3.

[0045] To avoid problems such as low utilization of the magnetic steel 12 and reduced power density caused by harmonic attenuation, the outer diameter of the rotor core 9 is preferably a full circle. The outer radius of the rotor core 9 is Rr1, and the inner radius of the stator core 2 is Rs2. The relationship between Rr1 and Rs2 satisfies the following: 0.45 mm ≤ Rs2 - Rr1 ≤ 1 mm. This satisfies assembly requirements, electromagnetic performance, and material cost. For example, in this embodiment, the inner radius of the stator core 2 is Rs2 = 41 mm, and the outer radius of the rotor core 9 is Rr1 = 40.9 mm, meaning Rs2 - Rr1 = 0.6 mm.

[0046] Preferably, the axial length of the stator core 2 is Lis, and the axial length of the rotor core 9 is Lir, and they satisfy: 0≤Lis-Lir≤2(Rs2-Rr1), where 50mm≤Lis≤100mm, while reducing the magnetic leakage at the end of the rotor core 9, so as to achieve serial design and distribution based on the same compressor shell diameter.

[0047] Preferably, the bottom radius of the stator slot 3 is Rs3, the outer radius of the stator core 2 is Rs1, and 8.3mm≤Rs1-Rs3≤14.6mm is satisfied, so as to ensure a certain slot area while forming a reasonable magnetic field distribution and ensuring a certain stiffness to reduce vibration noise.

[0048] Preferably, the central angle of the arc-shaped long slot 6 is θ1, and the central angle of the bottom of the stator slot 3 is θ2, satisfying θ1≤θ2, so as to weaken the flow of specific harmonics of the magnetic field.

[0049] Preferably, the top of the stator tooth 7 is recessed to form a flow groove 8 with a depth of hs1, satisfying 0<hs1≤Rs1-Rs3, while ensuring a large refrigerant flow area, taking into account the mechanical strength of the stator and the rationality of the magnetic field distribution.

[0050] Preferably, the inner radius of the arc-shaped slot 6 is Rs4, the outer radius of the arc-shaped slot 6 is Rs5, and the relationship Rs1 - hs1 < Rs4 < Rs5 < Rs1 is satisfied. The width of the arc-shaped slot 6 is hs2, and the relationship 1.2 mm ≤ hs2 ≤ 2 mm is satisfied, where hs2 = Rs5 - Rs4. This limitation allows for accurate positioning of the arc-shaped slot 6 to optimize magnetic field distribution while fully considering process feasibility.

[0051] Preferably, the width of the stator teeth 7 is ws1, which satisfies 12.2 mm ≤ ws1 ≤ 17.4 mm, to ensure a certain tooth width and yoke thickness ratio, a reasonable slot area, and a reasonable distribution of the magnetic field. For example, in this embodiment, the width of the stator teeth 7 is ws1 = 15.3 mm.

[0052] Preferably, the width of the through-flow groove 8 is ws2, the central angle of the groove 8 is θ3, and the following conditions are satisfied: ws1≤ws2≤2 Rs1 cos(θ3 / 2);

[0053] Where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1))≤θ3≤(360° / Q)-θ1;

[0054] To ensure that the refrigerant flow area is increased as much as possible under the premise of rationality of the magnetic circuit, thereby reducing temperature rise and improving motor efficiency.

[0055] Preferably, the magnets 12 evenly distributed along the circumference are inserted into the magnet slots 10 and then magnetized. After magnetization, the direction of the magnetic field must be perpendicular to the long side of the magnet 12, and the length of the long side of the magnet 12 is hpm.

[0056] The short side length of the magnetic steel 12 is wpm, which satisfies 1.8mm≤wpm≤3.5mm;

[0057] This ensures that the required magnetic field is provided within the limited rotor space and that the magnet 12 is not demagnetized due to the operating environment. For example, in this embodiment, the long side length of the magnet 12 is hpm=30 mm, and the short side length of the magnet 12 is wpm=2.5 mm.

[0058] Preferably, the width of the first magnetic isolation groove 11 is wg1, which satisfies 1.2 mm ≤ wg1 ≤ 2.5 mm;

[0059] The length of the first magnetic isolation groove 11 is hg1, which satisfies wg1<hg1≤wpm;

[0060] The distance between the first magnetic isolation groove 11 and the magnetic steel groove 10 is wb1, and the distance between the two first magnetic isolation grooves 11 is wb2. The distance between wb1 and wb2 satisfies the following: 0.45mm≤wb1≤wb2≤1.5mm.

[0061] By setting the position and related dimensions of the first magnetic isolation slot 11 according to the above definition, it is possible to reduce inter-pole magnetic leakage while optimizing the magnetic circuit and reducing back electromotive force harmonics.

[0062] Preferably, the vertical distance between the first magnetic isolation slot 11 and the rotor outer circumference is t0, the thickness of the first magnetic bridge 14 is t1, and the thickness of the second magnetic bridge 15 is t2. The following conditions are satisfied: 0.5 mm ≤ t0 ≤ t1, t2 ≤ 1.5 mm, where t1 = t2. While ensuring mechanical strength, these thicknesses can be appropriately reduced to minimize magnetic flux leakage and increase the utilization of the magnetic steel 12. For example, in this embodiment, t0 = 0.95 mm, and t1 = t2 = 0.8 mm, all falling between 0.5 mm and 1.5 mm.

[0063] Preferably, the width of the second magnetic isolation groove 13 is wg2, which satisfies 0.8 mm ≤ wg2 ≤ 1.8 mm;

[0064] The longest side length of the second magnetic isolation groove 13 is hg2, satisfying wg2≤hg2≤2.2mm;

[0065] The distance between the second magnetic isolation groove 13 and the magnetic steel groove 10 is wb3, which satisfies 0.45mm≤wb3≤1.5mm.

[0066] In a limited space, after the second magnetic isolation slot 13 is reasonably placed and dimensioned according to the above-mentioned limitations, the leakage flux can be further reduced and the effective value of the back electromotive force can be increased. The back electromotive force harmonics can also be further reduced to suppress torque pulsation and reduce vibration noise.

[0067] It should be noted that the "existing technology" appearing below specifically refers to the fact that the outer radius Rs1 of the stator core 2, the inner radius Rs2 of the stator core 2 and the axial length Lis of the stator core 2 do not satisfy: 1.282≤Lis / (Rs1-Rs2)≤2.778, the arc-shaped long slot 6 is not opened on the stator core 2, and the first magnetic isolation slot 11 and the second magnetic isolation slot 13 are not opened on the rotor core 9.

[0068] The Lis of the prior art is 70mm, Rs1 is 85mm, and Rs2 is 43.5mm, which are outside the scope of the present invention; the Lis of the present invention is 80mm, Rs1 is 75mm, and Rs2 is 41mm, which are within the scope of the present invention. Power density is defined as the ratio of motor output power to Lis. π Rs1 2 Under the ARI standard working condition, that is, the motor speed is 3600rpm, the torque is 9.4Nm, and the power is 3540W, the power density comparison between the permanent magnet motor 1 of the present invention and the prior art is as follows: Figure 5 In addition, the electromagnetic material costs of the existing solutions and the solutions of the present invention are statistically analyzed, and the cost comparison between the permanent magnet motor 1 of the present invention and the existing technology is shown in FIG. Figure 6 shown.

[0069] from Figure 5 It can be seen that the power density of the permanent magnet motor 1 of the present invention is increased by 11.06% compared with the permanent magnet motor of the prior art, and a smaller volume can produce greater output;

[0070] from Figure 6 It can be seen from the figure that the permanent magnet motor 1 of the present invention saves 16.51% of the electromagnetic cost compared with the permanent magnet motor of the prior art, thereby reducing the manufacturing cost of the compressor.

[0071] The efficiency of the motor will directly affect the energy efficiency of the compressor, such as Figure 7 The figure shows the motor efficiency diagram under the typical working condition of the compressor. Figure 7 It can be seen that the efficiency remains at a high level within a wide operating range, and is even higher at high speeds. The average efficiency under various operating conditions is as high as 95.26%, which is significantly improved compared to traditional compressors equipped with asynchronous motors.

[0072] like Figure 8-9 Shown are a comparison diagram of no-load back EMF harmonics between the permanent magnet motor using the embodiment of the present invention and the prior art at a speed of 1000 rpm, and a comparison diagram of no-load back EMF harmonic distortion rate between the permanent magnet motor using the embodiment of the present invention and the prior art.

[0073] from Figure 8 and Figure 9 It can be seen that after the first magnetic isolation slot 11, the second magnetic isolation slot 13 and the arc-shaped long slot 6 of the stator are introduced through the rotor, the fundamental amplitude of the no-load back electromotive force is increased, and most of the harmonics, especially the low-order harmonics, are reduced to varying degrees, and the harmonic distortion rate of the back electromotive force is greatly reduced, which fully proves that based on the above-mentioned specific implementation method, the sinusoidality of the no-load back electromotive force can be improved, thereby suppressing torque pulsation and reducing vibration noise.

[0074] like Figure 10 The figure shows a comparison of the electromagnetic torque waveforms of the permanent magnet motor of the present invention and the prior art under ARI standard operating conditions. The figure shows that the electromagnetic torque pulsation of the present invention is significantly lower than that of the prior art, and the electromagnetic torque quality is better, thereby achieving the purpose of reducing vibration and noise.

[0075] Depend on Figure 5-10 It can be seen that after adopting the implementation mode of the present invention, on the one hand, the power density is improved and the cost of electromagnetic materials is reduced. On the other hand, while ensuring that the amplitude of the no-load back-EMF fundamental wave does not decrease, the harmonics are weakened, the sinusoidality of the back-EMF waveform is improved, and the torque pulsation is suppressed.

[0076] The present invention also provides a variable frequency scroll compressor, which uses the above permanent magnet motor 1. The other structures and operations of the variable frequency scroll compressor are well known to those skilled in the art and will not be described in detail.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A permanent magnet motor, characterized in that: The invention comprises an external stator core and a rotor core arranged inside the stator core; The stator core includes stator slots evenly distributed along the circumference, wherein copper windings of circular enameled wire are embedded in the stator slots. A stator yoke is evenly distributed outside the bottom of each stator slot, and each stator yoke has an arc-shaped long slot. Stator teeth are provided between two adjacent stator slots, and the tops of the stator teeth are all recessed to form flow grooves. The rotor core is provided with uniformly distributed magnetic steel slots, two identical first magnetic isolation slots are provided between two adjacent magnetic steel slots, each of the magnetic steel slots is provided with magnetic steel with alternating north and south poles, and two symmetrically distributed second magnetic isolation slots are provided on the top of each magnetic steel; a first magnetic bridge and a second magnetic bridge are provided between the top of the magnetic steel slots and the second magnetic isolation slots and the outer circle of the rotor core; The outer radius of the stator core is Rs1, the inner radius of the stator core is Rs2, and the axial length of the stator core is Lis; wherein Rs1, Rs2, and Lis satisfy the following conditions: 1.282≤Lis / (Rs1-Rs2)≤2.778, and 36≤Rs1-Rs2≤39 mm; The stator slot bottom radius is Rs3, wherein Rs3 and Rs1 satisfy the following: 8.3 mm ≤ Rs1 - Rs3 ≤ 14.6 mm; The depth of the through-flow groove is hs1, and satisfies, 0<hs1≤Rs1-Rs3; the stator tooth width is ws1, and satisfies 12.2mm≤ws1≤17.4mm; the through-flow groove width is ws2, the through-flow groove central angle is θ3, and satisfies: ws1≤ws2≤2 Rs1 cos(θ3 / 2); where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1))≤θ3≤(360° / Q)-θ1; The width of the arc-shaped long groove is hs2, which satisfies 1.2mm≤hs2≤2mm; wherein hs2=Rs5-Rs4; The central angle of the arc-shaped long slot is θ1, and the central angle of the stator slot bottom is θ2, where θ1≤θ2; the inner radius of the arc-shaped long slot is Rs4, and the outer radius of the arc-shaped long slot is Rs5, and Rs1-hs1<Rs4<Rs5<Rs1 is satisfied; the magnetic field direction of the magnets uniformly distributed along the circumference after magnetization is perpendicular to the long side of the magnets, and the length of the long side of the magnets is hpm; The length of the short side of the magnetic steel is wpm, satisfying 1.8mm≤wpm≤3.5mm; the width of the first magnetic isolation groove is wg1, satisfying 1.2mm≤wg1≤2.5mm; the length of the first magnetic isolation groove is hg1, satisfying wg1<hg1≤wpm; the distance between the first magnetic isolation groove and the magnetic steel groove is wb1, the distance between the two first magnetic isolation grooves is wb2, and the distance between wb1 and wb2 satisfies: 0.45mm≤wb1≤wb2≤1.5mm.

2. The permanent magnet motor according to claim 1, characterized in that The number of stator slots is Q, and the copper windings of circular enameled wire embedded in the stator slots constitute a three-phase symmetrical winding. The number of magnetic steel slots distributed in the rotor core is p, wherein Q and p satisfy: p / Q=2 / 3.

3. The permanent magnet motor according to claim 1, characterized in that: The outer circle of the rotor core is a full circle, the center of which is at the center of the shaft; the outer radius of the rotor core is Rr1, and satisfies: 0.45mm≤Rs2-Rr1≤1mm; The axial length of the rotor core is Lir, and satisfies: 0≤Lis-Lir≤2(Rs2-Rr1), where 50mm≤Lis≤100mm.

4. The permanent magnet motor according to claim 1, characterized in that The vertical distance between the first magnetic isolation groove and the outer circle of the rotor is t0, the thickness of the first magnetic bridge is t1, the thickness of the second magnetic bridge is t2, and the following conditions are satisfied: 0.5mm≤t0≤t1≤1.5mm, where t1=t2.

5. The permanent magnet motor according to claim 1, characterized in that: The width of the second magnetic isolation groove is wg2, which satisfies 0.8mm≤wg2≤1.8mm; The longest side length of the second magnetic isolation groove is hg2, satisfying wg2≤hg2≤2.2mm; The distance between the second magnetic isolation groove and the magnetic steel groove is wb3, which satisfies 0.45mm≤wb3≤1.5mm.

6. A variable frequency scroll compressor, characterized in that: The method comprises the permanent magnet motor according to any one of claims 1 to 5.

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