Permanent magnet motor and variable-frequency scroll compressor

Abstract

The invention provides a permanent magnet motor and a variable-frequency scroll compressor, and relates to the technical field of scroll compressor design and manufacturing, and the permanent magnet motor comprises a stator iron core and a rotor iron core; the stator iron core comprises stator slots which are uniformly distributed along the circumference, copper windings are embedded in the slots, stator yokes which are uniformly distributed are arranged outside the bottom of each slot, each stator yoke is provided with an arc-shaped long slot, stator teeth are arranged between every two adjacent stator slots, and the tops of the stator teeth are sunken to form through-flow slots; the rotor core is internally provided with magnetic steel grooves which are uniformly distributed, two same first magnetic isolation grooves are arranged between two adjacent magnetic steel grooves, magnetic steel is arranged in the magnetic steel grooves, and the top of each magnetic steel is provided with two second magnetic isolation grooves which are symmetrically distributed. The outer side radius Rs1 of the stator core, the inner side radius Rs2 of the stator core and the axial length Lis of the stator core meet the following conditions: 1.282 < = Lis / (Rs1-Rs2) < = 2.778, and 34 < = Rs1-Rs2 < = 39 mm. The power density of the motor can be increased, the cost is reduced, the efficiency is improved, and the harmonic content is reduced so as to suppress torque ripple.

Description

Technical Field

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

[0002] The variable frequency scroll compressor is equipped with a permanent magnet motor and a high-performance frequency converter, and can be continuously adjusted within a wide speed range according to different ambient temperatures and load requirements to reduce the energy loss caused by frequent start and stop; in addition, due to its few moving parts and simple structure, it also has advantages such as high mechanical efficiency, low failure rate, low mechanical noise, and long service life.

[0003] With the continuous upgrading of China's energy efficiency standards, the surging demand in the heat pump field, the rapid development of new energy vehicles, the expansion of data centers and cold chains, etc., the variable frequency scroll compressor has gradually occupied a relatively high market share, and frequency conversion has become a major trend in the development of scroll compressors.

[0004] Although the permanent magnet motor itself has advantages such as high efficiency, high overload capacity, and wide speed range, it has many deficiencies compared with the traditional fixed frequency scroll compressor equipped with an asynchronous motor, such as high cost, low torque density, and large electromagnetic vibration and noise caused by a large number of harmonics in the motor itself, which brings technical challenges to the design of the permanent magnet motor, and relevant technologies need to be used to tackle these deficiencies.

[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 the harmonic content, and thus suppressing torque ripple. Summary of the Invention

[0006] In view of the many deficiencies of the variable frequency scroll compressor equipped with a permanent magnet motor compared with 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. By defining the relationship between the inner and outer radii of the stator and the core length, the present invention can increase the power density of the motor, reduce costs, and improve efficiency; by providing an arc-shaped long groove on the stator core, a first magnetic isolation groove and a second magnetic isolation groove on the rotor core, etc., the no-load back electromotive force waveform can be improved, thereby suppressing torque ripple and reducing vibration and noise.

[0007] The technical means adopted by the present invention are as follows: A permanent magnet motor, comprising an outer stator core and a rotor core disposed inside the stator core; The stator core includes stator slots evenly distributed along the circumference. A copper winding of circular enameled wire is embedded in the stator slots. A stator yoke is evenly arranged outside the bottom of each stator slot. An arc-shaped long slot is formed on each stator yoke. A stator tooth is arranged between two adjacent stator slots. The top of each stator tooth is recessed to form a current-carrying slot. The rotor core is provided with magnet slots evenly distributed therein. Two identical first magnetic isolation slots are arranged between two adjacent magnet slots. Magnets with alternating north and south poles are arranged in the magnet slots. Two symmetrically distributed second magnetic isolation slots are arranged on the top of each magnet. A first magnetic bridge and a second magnetic bridge are arranged between the top of the magnet slot and the second magnetic isolation slot 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. Among them, Rs1, Rs2, and Lis satisfy: 1.282 ≤ Lis / (Rs1 - Rs2) ≤ 2.778, and 34 ≤ Rs1 - Rs2 ≤ 39 mm.

[0008] Further, the number of stator slots is Q, and the copper windings of circular enameled wire embedded in the stator slots form a three-phase symmetric winding. The number of magnet slots distributed in the rotor core is p. Among them, Q and p satisfy: p / Q = 2 / 3.

[0009] Further, the outer circle of the rotor core is a complete circle, and its center is at the center of the rotating shaft. The outer radius of the rotor core is Rr1, and it satisfies: 0.45 mm ≤ Rs2 - Rr1 ≤ 1 mm. The axial length of the rotor core is Lir, and it satisfies: 0 ≤ Lis - Lir ≤ 2(Rs2 - Rr1), where 50 mm ≤ Lis ≤ 100 mm.

[0010] Further, the radius of the bottom of the stator slot is Rs3. Among them, Rs3 and Rs1 satisfy: 8.3 mm ≤ Rs1 - Rs3 ≤ 14.6 mm.

[0011] Further, the depth of the current-carrying slot is hs1, and it satisfies 0 < hs1 ≤ Rs1 - Rs3. The width of the stator tooth is ws1, and it satisfies 12.2 mm ≤ ws1 ≤ 17.4 mm. The width of the current-carrying slot is ws2, and the central angle of the current-carrying slot is θ3. And it satisfies: ws1 ≤ ws2 ≤ 2 Rs1 cos(θ3 / 2); where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1)) ≤ θ3 ≤ (360° / Q) - θ1.

[0012] 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 Rs1 - hs1 < Rs4 < Rs5 < Rs1 is satisfied; the width of the arc-shaped long slot is hs2, and 1.2 mm ≤ hs2 ≤ 2 mm is satisfied; where hs2 = Rs5 - Rs4.

[0013] Furthermore, after magnetization, the magnetic field direction of the magnet arranged circumferentially is perpendicular to the long side of the magnet, and the length of the long side of the magnet is hpm; the length of the short side of the magnet is wpm, and 1.8 mm ≤ wpm ≤ 3.5 mm is satisfied; the width of the first magnetic isolation slot is wg1, and 1.2 mm ≤ wg1 ≤ 2.5 mm is satisfied; the length of the first magnetic isolation slot is hg1, and wg1 < hg1 ≤ wpm is satisfied; the distance from the first magnetic isolation slot to the magnet slot is wb1, and the distance between two first magnetic isolation slots is wb2, and the following is satisfied between wb1 and wb2: 0.45 mm ≤ wb1 ≤ wb2 ≤ 1.5 mm.

[0014] Furthermore, the perpendicular distance from the first magnetic isolation slot to the outer circle of the rotor is t0, the thickness of the first magnetic bridge is t1, and the thickness of the second magnetic bridge is t2, and the following is satisfied: 0.5 mm ≤ t0 ≤ t1 ≤ 1.5 mm, where t1 = t2.

[0015] Furthermore, the width of the second magnetic isolation slot is wg2, and 0.8 mm ≤ wg2 ≤ 1.8 mm is satisfied; the length of the longest side of the second magnetic isolation slot is hg2, and wg2 ≤ hg2 ≤ 2.2 mm is satisfied; the distance from the second magnetic isolation slot to the magnet slot is wb3, and 0.45 mm ≤ wb3 ≤ 1.5 mm is satisfied.

[0016] The present invention also provides a variable-frequency scroll compressor, including the permanent magnet motor described above.

[0017] Compared with the prior art, the present invention has the following advantages: 1. By limiting that 1.282 ≤ Lis / (Rs1 - Rs2) ≤ 2.778 is satisfied among the outer radius Rs1, the inner radius Rs2, and the axial length Lis of the stator core, 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, and the efficiency of the motor can be improved.

[0018] 2. By introducing and reasonably arranging the first magnetic isolation slot, the second magnetic isolation slot, and the arc-shaped long slot of the rotor core, while ensuring that the power density is not reduced, certain specific harmonics can be reduced, thereby improving the sinusoidality of the back electromotive force waveform, further suppressing the torque ripple, and reducing the influence of vibration and noise. In addition, the introduction of the arc-shaped long slot can increase the refrigerant flow area inside the compressor, achieving the purpose of reducing the temperature rise of the stator core and increasing the efficiency.

[0019] 3. According to the magnetic circuit characteristics formed by the relationship that the number of magnetic steel slots p distributed in the rotor core satisfies p / Q = 2 / 3 with the number of stator slots Q, a current-carrying slot is opened at a specific position of the stator core to provide a path for the refrigerant to flow, further reducing the temperature rise of the motor and increasing the efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of the permanent magnet motor of the present invention.

[0022] Figure 2 It is a schematic structural diagram of the stator core in the present invention.

[0023] Figure 3 It is a schematic structural diagram of the rotor core in the present invention.

[0024] Figure 4 It is a partially enlarged view of the schematic structural diagram of the rotor in the present invention.

[0025] Figure 5 It is a comparison of the power density of the permanent magnet motor of the present invention with the prior art.

[0026] Figure 6 It is a comparison of the cost of the permanent magnet motor of the present invention with the prior art.

[0027] Figure 7 It is the efficiency diagram of the permanent magnet motor of the present invention under different working conditions.

[0028] Figure 8 It is a comparison diagram of the harmonic components of the no-load back electromotive force of the permanent magnet motor of the present invention with the prior art.

[0029] Figure 9 It is a comparison diagram of the harmonic distortion rate of the no-load back electromotive force of the permanent magnet motor of the present invention with the prior art.

[0030] Figure 10 It is a comparison diagram of the electromagnetic torque waveforms of the permanent magnet motor of the present invention with the prior art.

[0031] In the figure: 1. Permanent magnet motor; 2. Stator core; 3. Stator slot; 4. Copper winding; 5. Stator yoke; 6. Arc-shaped long slot; 7. Stator tooth; 8. Current-carrying slot; 9. Rotor core; 10. Magnet slot; 11. First magnetic isolation slot; 12. Magnet; 13. Second magnetic isolation slot; 14. First magnetic bridge; 15. Second magnetic bridge. Detailed implementation manners

[0032] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0033] To make the objectives, 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 with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also 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 their combinations.

[0035] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions and 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 the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings.

[0036] Such as Figure 1-4As shown in the figure, the present invention provides a permanent magnet motor. The permanent magnet motor 1 includes an outer stator core 2 and a rotor core 9 disposed inside the stator core 2. The stator core 2 includes stator slots 3 evenly distributed along the circumference. Copper windings 4 of circular enameled wires are embedded in the stator slots 3. An evenly distributed stator yoke 5 is provided outside the bottom of each stator slot 3. An arc-shaped long slot 6 is formed in each stator yoke 5. A stator tooth 7 is provided between two adjacent stator slots 3. The top of each stator tooth 7 is recessed to form a current-carrying groove 8. Uniformly distributed magnetic steel slots 10 are provided in the rotor core 9. Two identical first magnetic isolation slots 11 are provided between two adjacent magnetic steel slots 10. Magnetic steel 12 with alternating north and south poles is provided in the magnetic steel slots 10. Two symmetrically distributed second magnetic isolation slots 13 are provided on the top of each magnetic steel 12. A first magnetic bridge 14 and a second magnetic bridge 15 are provided between the top of the magnetic steel slot 10 and the second magnetic isolation slot 13 and the outer circle of the rotor core 9. 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. The following relationships are satisfied among Rs1, Rs2, and Lis: 1.282 ≤ Lis / (Rs1 - Rs2) ≤ 2.778, and 34 ≤ Rs1 - Rs2 ≤ 39 mm. The constraint conditions of the relationships among the three are obtained based on comprehensive factors such as the requirements of the compressor displacement for the motor, the reasonable design of the electric load and magnetic load, the limitation of the compressor housing volume, and the cost. The power density of the motor can be increased, the cost can be reduced, the efficiency can be improved, and the harmonic content can be reduced, thereby suppressing torque ripple.

[0037] Preferably, the number of stator slots 3 is Q. The circular enameled wires embedded in the stator slots 3 form a three-phase symmetrical winding 4. The number p of magnetic steel 12 distributed in the rotor core 9 satisfies p / Q = 2 / 3 to form a concentrated winding. The three-phase symmetrical winding 4 can be formed by mechanical winding or concentrated embedding to reduce the end length of the winding 4 and increase the efficiency. In this embodiment, for example, the number of stator slots 3 is 9, and the number of magnetic steel 12 is 6, satisfying the condition of p / Q = 2 / 3.

[0038] Preferably, to avoid problems such as low utilization rate of magnetic steel 12 and decreased power density caused by weakening harmonics, the outer circle of the rotor core 9 is a complete circle. The outer radius of the rotor core 9 is Rr1, and the inner radius of the stator core 2 is Rs2. The following relationship is satisfied between Rr1 and Rs2: 0.45 mm ≤ Rs2 - Rr1 ≤ 1 mm to meet the requirements of assembly, electromagnetic performance, and material cost. In this embodiment, for example, the inner radius Rs2 of the stator core 2 is 41 mm, and the outer radius Rr1 of the rotor core 9 is 40.9 mm, that is, Rs2 - Rr1 = 0.6 mm.

[0039] Preferably, the axial length of the stator core 2 is Lis, and the axial length of the rotor core 9 is Lir, and the following condition is satisfied: 0 ≤ Lis - Lir ≤ 2(Rs2 - Rr1), where 50 mm ≤ Lis ≤ 100 mm. While reducing the end leakage magnetic flux of the rotor core 9, a series design and distribution can be achieved on the basis of the same compressor shell diameter.

[0040] Preferably, the bottom radius of the stator slot 3 is Rs3, and the outer radius of the stator core 2 is Rs1, and the following condition is satisfied: 8.3 mm ≤ Rs1 - Rs3 ≤ 14.6 mm. While ensuring a certain slot area, a reasonable magnetic field distribution is formed to ensure a certain stiffness to reduce vibration and noise.

[0041] 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, and the following condition is satisfied: θ1 ≤ θ2, so as to weaken the circulation of specific sub-harmonics of the magnetic field.

[0042] Preferably, the top of the stator tooth 7 is recessed to form a flow-through slot 8 with a depth of hs1, and the following condition is satisfied: 0 < hs1 ≤ Rs1 - Rs3. While ensuring a large refrigerant flow area, the mechanical strength of the stator and the rationality of the magnetic field distribution are considered.

[0043] Preferably, the inner radius of the arc-shaped long slot 6 is Rs4, the outer radius of the arc-shaped long slot 6 is Rs5, and the following condition is satisfied: Rs1 - hs1 < Rs4 < Rs5 < Rs1. The width of the arc-shaped long slot 6 is hs2, and the following condition is satisfied: 1.2 mm ≤ hs2 ≤ 2 mm, where hs2 = Rs5 - Rs4. According to this limitation, the position of the arc-shaped long slot 6 can be accurately located on the premise of fully considering the process feasibility to optimize the magnetic field distribution.

[0044] Preferably, the width of the stator tooth 7 is ws1, and the following condition is satisfied: 12.2 mm ≤ ws1 ≤ 17.4 mm. To ensure a certain tooth width to yoke thickness ratio, a reasonable slot area, a reasonable magnetic field distribution, etc. In this embodiment, the width ws1 of the stator tooth 7 is 15.3 mm.

[0045] Preferably, the width of the flow-through slot 8 is ws2, and the central angle of the slot 8 is θ3, and the following conditions are satisfied: ws1 ≤ ws2 ≤ 2 Rs1 cos(θ3 / 2); where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1)) ≤ θ3 ≤ (360° / Q) - θ1; To ensure that on the premise of the rationality of the magnetic circuit, the refrigerant flow area is increased as much as possible, thereby reducing the temperature rise and improving the motor efficiency.

[0046] Preferably, after the permanent magnets 12 evenly distributed along the circumference are inserted into the permanent magnet slots 10, magnetization treatment is performed. After magnetization, the magnetic field direction needs to be perpendicular to the long side of the permanent magnet 12, and the length of the long side of the permanent magnet 12 is hpm; The length of the short side of the permanent magnet 12 is wpm, satisfying 1.8 mm ≤ wpm ≤ 3.5 mm; To ensure that the required magnetic field is provided within the limited rotor space and the permanent magnet 12 will not be demagnetized due to the operating environment. For example, in this embodiment, the length of the long side of the permanent magnet 12 hpm = 30 mm, and the length of the short side of the permanent magnet 12 wpm = 2.5 mm.

[0047] Preferably, the width of the first magnetic isolation slot 11 is wg1, satisfying 1.2 mm ≤ wg1 ≤ 2.5 mm; The length of the first magnetic isolation slot 11 is hg1, satisfying wg1 < hg1 ≤ wpm; The distance between the first magnetic isolation slot 11 and the permanent magnet slot 10 is wb1, and the distance between the two first magnetic isolation slots 11 is wb2. Between wb1 and wb2, it satisfies: 0.45 mm ≤ wb1 ≤ wb2 ≤ 1.5 mm.

[0048] By setting the position and related dimensions of the first magnetic isolation slot 11 according to the above limitations, while reducing the inter-pole leakage magnetic flux, the magnetic circuit can be optimized and the back electromotive force harmonics can be reduced.

[0049] Preferably, the perpendicular distance from the first magnetic isolation slot 11 to the outer circle of the rotor is t0, the thickness of the first magnetic bridge 14 is t1, and the thickness of the second magnetic bridge 15 is t2, and it satisfies: 0.5 mm ≤ t0 ≤ t1, t2 ≤ 1.5 mm, where t1 = t2. On the premise of meeting the mechanical strength, the above thickness can be appropriately reduced to reduce the leakage magnetic flux and increase the utilization rate of the permanent magnet 12. For example, in this embodiment, t0 = 0.95 mm, t1 = t2 = 0.8 mm are both between 0.5 mm and 1.5 mm.

[0050] Preferably, the width of the second magnetic isolation slot 13 is wg2, satisfying 0.8 mm ≤ wg2 ≤ 1.8 mm; The length of the longest side of the second magnetic isolation slot 13 is hg2, satisfying wg2 ≤ hg2 ≤ 2.2 mm; The distance between the second magnetic isolation slot 13 and the permanent magnet slot 10 is wb3, satisfying 0.45 mm ≤ wb3 ≤ 1.5 mm.

[0051] Within the limited space, after reasonably placing the second magnetic isolation slot 13 according to the above limitations and reasonably specifying the dimensions, the leakage magnetic flux can be further reduced, the effective value of the back electromotive force can be increased, and the back electromotive force harmonics can be further reduced, thereby suppressing the torque ripple and reducing the vibration and noise.

[0052] It should be noted that the "prior art" mentioned below specifically refers to the situation where the outer radius Rs1, 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, no arc-shaped long slot 6 is opened in the stator core 2, and no first magnetic isolation slot 11 and second magnetic isolation slot 13 are opened in the rotor core 9.

[0053] For the prior art, Lis is 70 mm, Rs1 is 85 mm, and Rs2 is 43.5 mm, which is outside the scope defined by the present invention; for the present invention, Lis is 80 mm, Rs1 is 75 mm, and Rs2 is 41 mm, which is within the scope defined by the present invention. The power density is defined as the ratio of the motor output power to Lis. π Rs1 2 Then under the ARI standard working conditions, that is, when the motor speed corresponds to 3600 rpm, the torque is 9.4 Nm, and the power is 3540 W, the comparison of the power density between the permanent magnet motor 1 of the present invention and the prior art is as Figure 5 shown. In addition, the electromagnetic material costs of the existing solution and the solution of the present invention are counted, and the comparison of the costs between the permanent magnet motor 1 of the present invention and the prior art is as Figure 6 shown.

[0054] From Figure 5 it can be seen that compared with the permanent magnet motor of the prior art, the power density of the permanent magnet motor 1 of the present invention has increased by 11.06%, and a smaller volume can generate a greater output force; From Figure 6 it can be seen that compared with the permanent magnet motor of the prior art, the electromagnetic cost of the permanent magnet motor 1 of the present invention has been saved by 16.51%, reducing the manufacturing cost of the compressor.

[0055] The efficiency of the motor will directly affect the energy efficiency of the compressor. As Figure 7 shown is the motor efficiency diagram under the typical working conditions of the compressor. From Figure 7 it can be seen that in a wide operating range, the efficiency remains at a high level, and the efficiency is higher at high speeds. The average efficiency under each working condition is as high as 95.26%. Compared with the traditional compressor equipped with an asynchronous motor, the efficiency has been significantly improved.

[0056] As Figure 8-9 shown are respectively the comparison diagram of each harmonic of the no-load back electromotive force between the permanent magnet motor of the embodiment of the present invention and the prior art at a speed of 1000 rpm, and the comparison diagram of the harmonic distortion rate of the no-load back electromotive force between the permanent magnet motor of the embodiment of the present invention and the prior art.

[0057] From Figure 8 and Figure 9It can be seen that after introducing the first magnetic isolation slot 11, the second magnetic isolation slot 13 and the arc-shaped long slot 6 of the stator through the rotor, the fundamental wave amplitude of the no-load back electromotive force increases, and most of the harmonics, especially the low-order harmonics, are reduced to varying degrees. The harmonic distortion rate of the back electromotive force decreases significantly, fully demonstrating that based on the above specific implementation manners, the sinusoidality of the no-load back electromotive force can be improved, thereby suppressing torque ripple and reducing vibration and noise.

[0058] As Figure 10 shown is the comparison diagram of the electromagnetic torque waveforms of the permanent magnet motor of the present invention and the prior art under the ARI standard working conditions. It can be seen from the figure that the electromagnetic torque ripple of the present invention is significantly lower than that of the prior art, and the quality of the electromagnetic torque is better, thereby achieving the purpose of reducing vibration and noise.

[0059] From Figure 5-Figure 10 it can be known that after adopting the implementation manner of the present invention, on the one hand, the power density is improved to reduce the cost of electromagnetic materials, and on the other hand, while ensuring that the fundamental wave amplitude of the no-load back electromotive force does not decrease, the harmonics are weakened, the sinusoidality of the back electromotive force waveform is improved, and the torque ripple is suppressed.

[0060] The present invention also proposes a variable frequency scroll compressor, which adopts the permanent magnet motor 1 as above. The other structures and operations of the variable frequency scroll compressor are known to those skilled in the art and will not be described in detail.

[0061] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A permanent magnet motor, characterized in that, An outer stator core and a rotor core disposed inside the stator core; The stator core includes stator slots evenly distributed in a circumferential direction. Copper windings of circular enameled wires are embedded in the stator slots. Uniform stator yokes are provided outside the bottom of each stator slot. Arc-shaped long slots are formed in each stator yoke. Stator teeth are provided between adjacent two stator slots. The tops of the stator teeth are all recessed to form current-carrying grooves; Uniformly distributed magnet slots are provided inside the rotor core. Two identical first magnetic isolation slots are provided between adjacent two magnet slots. Magnets with alternating north and south poles are provided in the magnet slots. Two symmetrically distributed second magnetic isolation slots are provided on the top of each magnet; A first magnetic bridge and a second magnetic bridge are provided between the top of the magnet slot and the second magnetic isolation slot 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; Among them, Rs1, Rs2, and Lis satisfy: 1.282 ≤ Lis / (Rs1 - Rs2) ≤ 2.778, and 34 ≤ Rs1 - Rs2 ≤ 39 mm.

2. The permanent magnet motor according to claim 1, wherein, The number of the stator slots is Q. The copper windings of circular enameled wires embedded in the stator slots form a three-phase symmetrical winding. The number of magnet slots distributed in the rotor core is p. Among them, 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 complete circle, and its center is at the center of the rotating shaft; The outer radius of the rotor core is Rr1, and it satisfies: 0.45 mm ≤ Rs2 - Rr1 ≤ 1 mm; The axial length of the rotor core is Lir, and it satisfies: 0 ≤ Lis - Lir ≤ 2(Rs2 - Rr1), where 50 mm ≤ Lis ≤ 100 mm.

4. The permanent magnet motor according to claim 1, characterized in that The radius of the bottom of the stator slot is Rs3. Among them, Rs3 and Rs1 satisfy: 8.3 mm ≤ Rs1 - Rs3 ≤ 14.6 mm.

5. The permanent magnet motor according to claim 4, wherein The depth of the current-carrying groove is hs1, and it satisfies 0 < hs1 ≤ Rs1 - Rs3; The width of the stator tooth is ws1, and it satisfies 12.2 mm ≤ ws1 ≤ 17.4 mm; The width of the flow channel is ws2, and the central angle of the flow channel is θ3, and they satisfy: ws1 ≤ ws2 ≤ 2 Rs1 cos(θ3 / 2); where θ3 satisfies: 2 arcsin(ws1 / (2 Rs1)) ≤ θ3 ≤ (360° / Q) - θ1.

6. The permanent magnet motor according to claim 5, characterized in that, The central angle of the arc-shaped long slot is θ1, and the central angle of the bottom of the stator slot is θ2. Among them, 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 it satisfies Rs1 - hs1 < Rs4 < Rs5 < Rs1; The width of the arc-shaped long slot is hs2, and it satisfies 1.2 mm ≤ hs2 ≤ 2 mm; Among them, hs2 = Rs5 - Rs4.

7. The permanent magnet motor according to claim 1, characterized in that, The magnetic field direction of the uniformly distributed magnets in the circumferential direction is perpendicular to the long side of the magnet after magnetization. The long side length of the magnet is hpm; The short side length of the magnet is wpm, and it satisfies 1.8 mm ≤ wpm ≤ 3.5 mm; The width of the first magnetic isolation slot is wg1, and it satisfies 1.2 mm ≤ wg1 ≤ 2.5 mm; The length of the first magnetic isolation slot is hg1, and it satisfies wg1 < hg1 ≤ wpm; The distance between the first magnetic isolation slot and the magnet slot is wb1, and the distance between the two first magnetic isolation slots is wb2. wb1 and wb2 satisfy: 0.45 mm ≤ wb1 ≤ wb2 ≤ 1.5 mm.

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

9. The permanent magnet motor according to claim 1, wherein The width of the second magnetic isolation groove is wg2, and 0.8 mm ≤ wg2 ≤ 1.8 mm is satisfied; The length of the longest side of the second magnetic isolation groove is hg2, and wg2 ≤ hg2 ≤ 2.2 mm is satisfied; The distance from the second magnetic isolation groove to the permanent magnet groove is wb3, and 0.45 mm ≤ wb3 ≤ 1.5 mm is satisfied.

10. A variable-frequency scroll compressor, characterized in that, It includes a permanent magnet motor according to any one of claims 1-9.

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