Permanent magnet motor, compressor and refrigeration equipment

Abstract

The invention discloses a permanent magnet motor, a compressor and refrigeration equipment, and relates to the technical field of refrigeration equipment, the permanent magnet motor comprises a motor rotor and a motor stator, the motor rotor comprises a rotor iron core and permanent magnets, and the permanent magnets are embedded in permanent magnet grooves; the motor stator sleeves the periphery of the motor rotor, the motor stator comprises a stator core and a stator winding, the stator core comprises a stator yoke and stator teeth, the plurality of stator teeth are arranged at intervals along the inner circumference of the stator yoke, a stator slot is formed between every two adjacent stator teeth, and the stator winding is wound in the stator slots. According to the technical scheme provided by the invention, N, Q and L1 meet the condition that N / (Q * L1) is greater than or equal to 0.12 and less than or equal to 0.2 by adjusting the relationship among the number N of winding turns on a single stator tooth of the permanent magnet motor, the number Q of stator slots and the length L1 of the permanent magnet in the axial direction of the rotor core, so that the permanent magnet motor can improve the counter electromotive force of the permanent magnet motor while meeting the operation range requirement under the maximum pressure difference, and the service life of the permanent magnet motor is prolonged. The energy efficiency of the permanent magnet motor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration equipment, and in particular to a permanent magnet motor, a compressor and a refrigeration equipment. BACKGROUND

[0002] Permanent magnet motors are high-efficiency and high-performance motors widely used in electric vehicles, robots, wind power generation and other fields. The energy efficiency of a permanent magnet motor is influenced by multiple factors, including motor design, material selection, temperature management, and control strategy. Among them, the characteristics of back electromotive force have a direct impact on the energy efficiency of the motor. In addition, broadening the operating range is crucial to improving the adaptability and flexibility of the motor. In some application scenarios, such as electric vehicles, the motor needs to operate efficiently in a wide range of speeds. However, when the motor speed is too high, the back electromotive force may approach or exceed the power supply voltage, which will limit the motor's acceleration capability and torque output at high speed. Therefore, with the growing demand for higher energy efficiency and wider operating range, the design and optimization of permanent magnet motors face new challenges. SUMMARY

[0003] The main purpose of the present application is to provide a permanent magnet motor, a compressor and a refrigeration equipment, which aims to improve the back electromotive force of the permanent magnet motor and improve the energy efficiency of the permanent magnet motor while meeting the operating range requirements under the maximum pressure difference.

[0004] To achieve the above-mentioned purpose, the permanent magnet motor provided by the present application comprises:

[0005] A motor rotor comprising a rotor core and permanent magnets, the rotor core is provided with a plurality of permanent magnet slots along its circumferential direction, the permanent magnets are embedded in the permanent magnet slots, and the length of the permanent magnets along the axial direction of the rotor core is L1;

[0006] A motor stator is sleeved on the outer periphery of the motor rotor, the motor stator comprises a stator core and a stator winding, the stator core comprises a stator yoke and a stator tooth, a plurality of stator teeth are arranged along the inner periphery of the stator yoke, a stator slot is formed between adjacent two stator teeth, and the number of stator slots is Q; the stator winding is wound on the stator tooth, and the number of turns of the stator winding on each stator tooth is N;

[0007] Wherein, 0.12≤N / (Q×L1)≤0.2.

[0008] In an embodiment, the length of the rotor core along its axial direction is L2, the length of the stator core along its axial direction is L3, and 0mm≤L2-L3≤2mm.

[0009] In an embodiment, 0mm≤L1-L3≤1mm.

[0010] In an embodiment, 20mm≤L1≤50mm.

[0011] In an embodiment, 20mm≤L2≤50mm.

[0012] In an embodiment, 20mm≤L3≤50mm.

[0013] In an embodiment, the plurality of permanent magnets form 2P magnetic poles in the circumferential direction of the rotor core, and Q and 2P satisfy: 1

[0014] In an embodiment, 15≤Q≤18.

[0015] In an embodiment, 10≤2P≤12.

[0016] In an embodiment, Q / 2P=3 / 2.

[0017] In an embodiment, 50≤N≤140.

[0018] The application further provides a compressor comprising the permanent magnet motor.

[0019] The application further provides a refrigeration device comprising the compressor.

[0020] The technical scheme of the application adjusts the relationship among the number of turns N of the winding on a single stator tooth of the permanent magnet motor, the number Q of stator slots, and the length L1 of the permanent magnet along the axial direction of the rotor core, so that N, Q, and L1 satisfy: 0.12≤N / (QxL1)≤0.2, the permanent magnet motor can meet the operating range requirement under the maximum pressure difference, improve the back electromotive force of the permanent magnet motor, and improve the energy efficiency of the permanent magnet motor. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained according to the structures shown in the drawings without creative labor for those skilled in the art.

[0022] Figure 1 The structural schematic diagram of an embodiment of the permanent magnet motor provided by the application;

[0023] Figure 2 The structural schematic diagram of an embodiment of the permanent magnet motor provided by the application; Figure 1 The local enlarged view of A in FIG. 4;

[0024] Figure 3 The structural schematic diagram of an embodiment of the compressor provided by the application;

[0025] Figure 4 The curves show the relationship between N / (Q×L1) and the speed of the permanent magnet motor and the COP of the compressor.

[0026] Explanation of icon numbers:

[0027] 10. Permanent magnet motor; 100. Motor rotor; 200. Motor stator; 110. Rotor core; 111. Permanent magnet slot; 120. Permanent magnet; 210. Stator core; 211. Stator yoke; 212. Stator teeth; 213. Stator slot; 220. Stator winding.

[0028] 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

[0029] 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.

[0030] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications 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 indications will also change accordingly.

[0031] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the 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. 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.

[0032] This invention proposes a permanent magnet motor 10.

[0033] Please see Figure 1In one embodiment of the present invention, the permanent magnet motor 10 includes a motor rotor 100 and a motor stator 200. The motor rotor 100 includes a rotor core 110 and permanent magnets 120. The rotor core 110 is provided with a plurality of permanent magnet slots 111 spaced apart along its circumference. The permanent magnets 120 are embedded in the permanent magnet slots 111, and the length of the permanent magnets 120 along the axial direction of the rotor core 110 is L1. The motor stator 200 is sleeved on the outer periphery of the motor rotor 100. The stator 200 includes a stator core 210 and a stator winding 220. The stator core 210 includes a stator yoke 211 and stator teeth 212. Multiple stator teeth 212 are spaced apart along the inner circumference of the stator yoke 211. A stator slot 213 is formed between two adjacent stator teeth 212. The number of stator slots 213 is Q. The stator winding 220 is wound on the stator teeth 212. The number of turns on each stator tooth 212 is N. Wherein, 0.12≤N / (Q×L1)≤0.2.

[0034] Specifically, the permanent magnet motor 10 includes a motor rotor 100 and a motor stator 200, with the stator 200 fitted around the outer periphery of the motor rotor 100. The motor stator 200 includes a stator core 210 and a stator winding 220 for generating a rotating magnetic field. The stator core 210 is formed by stacking silicon steel plates. The stator core 210 includes a stator yoke 211 and stator teeth 212. The stator yoke 211 is annular, and multiple stator teeth 212 are spaced circumferentially along the inner side of the stator yoke 211. Stator slots 213 are defined between adjacent stator teeth 212, and the number of stator slots 213 is the same as the number of stator teeth 212. The stator winding 220 passes through the stator slots 213 and is directly wound around the stator teeth 212. When three-phase alternating current is applied to the stator winding 220, a rotating magnetic field is generated. The permanent magnets 120 on the motor rotor 100 interact with this rotating magnetic field to generate torque, thereby driving the permanent magnet motor 10 to rotate. The motor rotor 100 includes a rotor core 110 and permanent magnets 120. The permanent magnets 120 can generate a constant magnetic field and interact with the rotating magnetic field to generate torque. The motor rotor 100 can rotate relative to the motor stator 200 to achieve the normal operation of the permanent magnet motor 10. The rotor core 110 is made of high-permeability material or silicon steel laminations, which has high permeability, high structural strength, and is easy to process. The permanent magnets 120 are embedded in the permanent magnet slots 111. When embedding, the permanent magnets 120 under the same magnetic pole are required to have the same polarity in the direction of the outer periphery of the motor rotor 100. At the same time, the permanent magnets 120 of adjacent magnetic poles are required to have opposite magnetism. Multiple magnetic poles are distributed alternately with N poles and S poles in the circumferential direction of the rotor core 110. The permanent magnet 120 slot 111 can be straight, arc-shaped, "U"-shaped, "V"-shaped, or "W"-shaped. The straight or arc-shaped permanent magnet 120 slot 111 is embedded with a corresponding straight or arc-shaped permanent magnet 120. The "U"-shaped, "V"-shaped, or "W"-shaped permanent magnet 120 slot 111 is formed by a combination of multiple straight or arc-shaped permanent magnets 120.

[0035] The length of the permanent magnet 120 along the axial direction of the rotor core 110 can be measured using vernier calipers, digital micrometers, rulers, or measuring tapes. For example, place the permanent magnet 120 on a platform, use the inner and outer measuring jaws of a vernier caliper to clamp the two ends of the permanent magnet 120 along the axial direction of the rotor core 110, and read the measurement. Please refer to [link / reference]. Figure 1 and Figure 2 The number of winding turns N on each stator tooth 212 and the number of stator slots Q can be directly observed. Figure 2 The number of windings within the wire frame is equal to the number of winding turns N on one stator tooth 212.

[0036] The effective value E of the induced electromotive force (EMF) of each phase of stator winding 220 can be expressed by the following formula: E = 4.44KfN1φ. Where, E is the effective value of the induced EMF per phase (volts); K is the winding coefficient of stator winding 220 (less than 1), which depends on the specific structure of the winding; f is the frequency of the induced EMF of stator winding 220 (Hertz), usually equal to the frequency of the power supply; N1 is the number of turns of the coil connected in series in each phase of stator winding 220; and φ is the magnetic flux per pole of the rotating magnetic field, i.e., the maximum value (Weber) of the alternating magnetic flux passing through stator winding 220.

[0037] It is known that the number of turns N on each stator tooth 212, the number Q of stator slots 213, and the length L1 of the permanent magnet 120 along the axial direction of the rotor core 110 affect the back electromotive force (EMF) generated during the operation of the permanent magnet motor 10. Among these, the number of turns N directly affects the rate of change of magnetic flux linkage, thus affecting the magnitude of the back EMF. Understandably, each additional turn increases the magnetic flux linkage through the stator winding 220. According to Faraday's law of electromagnetic induction, the rate of change of magnetic flux is proportional to the induced EMF. Therefore, increasing the number of turns in the stator winding 220 increases the induced back EMF. Since the resistance of the stator winding 220 increases with the number of turns, this may lead to a decrease in the current during the operation of the permanent magnet motor 10.

[0038] Increasing the number Q of stator slots 213 allows for the placement of more stator windings 220, thereby improving the magnetic field distribution and achieving a smoother magnetic field distribution, which helps to improve the efficiency of the permanent magnet motor 10. Therefore, the number of stator slots 213 has a greater impact on the distribution of the magnetic field inside the permanent magnet motor 10 and the physical layout of the stator windings 220, indirectly affecting the back electromotive force.

[0039] Increasing the length L1 of the permanent magnet 120 along the axial direction of the rotor core 110 typically increases the magnetic flux density and the rate of change of flux linkage. At the same rotational speed, more magnetic flux passes through the stator winding 220, resulting in a larger back EMF. A higher back EMF can help the permanent magnet motor 10 operate more efficiently at high voltages, thereby improving the output power and efficiency of the permanent magnet motor 10 at high speeds.

[0040] However, the rotational speed of the permanent magnet motor 10 is directly related to the back electromotive force (EMF). The back EMF is the voltage generated by the permanent magnet motor 10 cutting magnetic field lines when it rotates, and its magnitude is proportional to the rotational speed. As the rotational speed increases, the back EMF increases, resulting in a reduction in the input current required by the permanent magnet motor 10 under the same load. A lower input current means less copper loss on the stator winding 220, thereby improving the efficiency of the permanent magnet motor 10. However, when the rotational speed of the permanent magnet motor 10 is too high, the back EMF may approach or exceed the supply voltage, which will limit the acceleration capability and torque output of the permanent magnet motor 10 at high speeds.

[0041] According to experimental results, by adjusting the relationship between the number of winding turns N on each stator tooth 212, the number of stator slots 213 Q, and the length L1 of the permanent magnet 120 along the axial direction of the rotor core 110, N, Q, and L1 can satisfy: 0.12≤N / (Q×L1)≤0.2. This allows the permanent magnet motor 10 to meet the operating range requirements under the maximum differential pressure while improving the back EMF of the permanent magnet motor 10 and increasing its energy efficiency.

[0042] Please refer to Table 1 and Figure 4 As N / (Q×L1) increases, the compressor's COP (Coefficient of Performance) also increases. When N / (Q×L1) ≥ 0.12, the compressor's COP exceeds 412.0%, improving the back EMF of the permanent magnet motor 10 and enhancing its energy efficiency. However, as N / (Q×L1) increases, the maximum speed of the permanent magnet motor 10 under the maximum pressure difference decreases. When N / (Q×L1) ≥ 0.2, its maximum speed drops to 120 rpm, narrowing the operating range of the permanent magnet motor 10. Therefore, when 0.12 ≤ N / (Q×L1) ≤ 0.2, the maximum speed of the permanent magnet motor 10 under the maximum pressure difference is between 120 rpm and 160 rpm, which meets the operating range requirements of the permanent magnet motor 10 under the maximum pressure difference. Meanwhile, the compressor's COP is between 412.0% and 419.0%, the back EMF of the permanent magnet motor 10 is improved, and the energy efficiency of the permanent magnet motor 10 is increased.

[0043] Table 1: Relationship between N / (Q×L1) and permanent magnet motor speed and compressor COP

[0044]

[0045] In one implementation, please refer to Figure 3 The length of the rotor core 110 along its axial direction is L2, and the length of the stator core 210 along its axial direction is L3, where 0mm≤L2-L3≤2mm.

[0046] The motor rotor 100 includes a rotor core 110 made of stacked silicon steel sheets, and the axial length of the motor rotor 100 is equal to the thickness of its multiple layers of stacked silicon steel sheets. Similarly, the motor stator 200 includes a stator core 210 made of stacked silicon steel sheets, and the axial length of the motor stator 200 is equal to the thickness of its multiple layers of stacked silicon steel sheets. 0mm ≤ L2 - L3 ≤ 2mm means that the axial length of the rotor core 110 is not less than the axial length of the stator core 210, which also means that the thickness of the stacked silicon steel sheets in the motor rotor 100 is not less than the thickness of the stacked silicon steel sheets in the motor stator 200. Therefore, the amount of permanent magnets 120 placed inside the rotor core 110 will be larger, increasing the magnetic flux generated by the motor rotor 100, thereby improving the permanent magnet torque of the permanent magnet motor 10, increasing the output capacity of the permanent magnet motor 10, and improving the performance of the permanent magnet motor 10.

[0047] Furthermore, end plates are typically installed at both ends of the motor rotor 100 in the axial direction to fix the permanent magnet 120 in the slot 111. The length of the rotor core 110 in the axial direction is not less than the length of the stator core 210 in the axial direction. The two ends of the rotor core 110 can be flush with or slightly protrude from the two ends of the stator core 210 in the axial direction, so that the end plates can be installed with the rotor core 110 and fixed to the permanent magnet 120.

[0048] In one embodiment, the length of the permanent magnet 120 along the axial direction of the rotor core 110 is L1, and the length of the stator core 210 along its axial direction is L3, where 0mm≤L1-L3≤1mm.

[0049] 0mm≤L1-L3≤1mm means that the length of the permanent magnet 120 along the axial direction of the rotor core 110 is not less than the length of the stator core 210 along its axial direction; at the same time, the length of the permanent magnet 120 along the axial direction of the rotor core 110 is not greater than the length of the stator core 210 along its axial direction, that is, L2≥L1≥L3. When the length of the permanent magnet 120 along the axial direction of the rotor core 110 is the same as or slightly longer than the length of the stator core 210 along its axial direction, the rate of change of magnetic flux linkage and magnetic flux density will increase. At the same speed, more magnetic flux passes through the stator winding 220, thereby generating a larger back electromotive force and output torque, which can improve the output power and efficiency of the permanent magnet motor 10 when running at high speed.

[0050] Similarly, the two ends of the permanent magnet 120 can be flush with the two ends of the stator core 210 in the axial direction, or slightly protrude from the two ends of the stator core 210 in the axial direction, and the two ends of the permanent magnet 120 will not protrude from the two ends of the rotor core 110 in the axial direction, so as to facilitate the installation between the end plate and the rotor core 110, and at the same time, to fix the permanent magnet 120.

[0051] In one embodiment, the length of the permanent magnet 120 along the axial direction of the rotor core 110 is L1, where 20mm ≤ L1 ≤ 50mm.

[0052] As the length of the permanent magnet 120 increases, it can provide more magnetic flux, thereby increasing the flux linkage through the stator winding 220. More flux passes through the stator winding 220 during rotor rotation, increasing the rate of change of flux linkage, flux density, and output torque of the permanent magnet motor 10. However, a longer permanent magnet 120 requires a better cooling system to prevent magnetic degradation due to overheating. The permanent magnet 120 is expensive, increasing material costs and complicating the assembly process. Simultaneously, the size of the motor stator 200, which is fitted around the motor rotor 100, also increases, making the permanent magnet motor 10 larger. This not only hinders weight reduction but also increases manufacturing costs. When 20mm ≤ L1 ≤ 50mm, it ensures that the permanent magnet 120 can provide sufficient magnetic flux while keeping the overall size of the permanent magnet motor 10 small and reducing total production costs.

[0053] In one implementation, please refer to Figure 3 The length of the rotor core 110 along its axial direction is L2, 20mm≤L2≤50mm.

[0054] L1 and L2 can both take the minimum value of 20mm, or the maximum value of 50mm. Alternatively, they can take any value between 20mm and 50mm, provided that L2≥L1. This ensures that the permanent magnet 120 can provide sufficient magnetic flux, while also keeping the overall size of the permanent magnet motor 10 small and reducing the total production cost.

[0055] In one implementation, please refer to Figure 3 The length of the stator core 210 along its axial direction is L3, 20mm≤L3≤50mm.

[0056] L1, L2, and L3 can all take the minimum value of 20mm, or the maximum value of 50mm. Alternatively, they can take any value between 20mm and 50mm, provided that L2≥L1≥L3. This ensures that the permanent magnet 120 can provide sufficient magnetic flux, while also keeping the overall size of the permanent magnet motor 10 small and reducing the total production cost.

[0057] In one implementation, please refer to Figure 1 Multiple permanent magnets 120 form 2P magnetic poles in the circumferential direction of the rotor core 110, and Q and 2P satisfy: 1 ​​< Q / 2P < 3.

[0058] 2P represents the number of circumferential magnetic poles formed in the rotor core 110, and P represents the number of pole pairs in the motor rotor 100. Different ratios of Q / 2P can have different effects on the waveform quality and ripple torque of the back EMF, thus significantly impacting the back EMF characteristics and energy efficiency of the permanent magnet motor 10. Therefore, to reduce tooth harmonic magnetic fields and torque ripple, the number of stator slots 213 and the number of pole pairs are usually optimized. The Q / 2P ratio determines the magnetic field interaction between the motor stator 200 and the motor rotor 100. Different slot ratios affect the fundamental magnetic flux density distribution of the permanent magnet motor 10, thereby affecting the motor's performance. When there is no good match between the two, high tooth harmonics may be generated, leading to additional losses and torque ripple, thus affecting the efficiency and noise level of the permanent magnet motor 10. A suitable slot ratio helps to obtain a more uniform magnetic flux density distribution, thereby improving the motor's output capacity and reducing iron losses. When 1 < Q / 2P < 3, there is a good ratio between the number of stator slots 213 and the number of pole pairs, which can optimize the magnetic flux density distribution, reduce losses and torque fluctuations, thereby reducing the noise of the permanent magnet motor 10 and improving the performance of the permanent magnet motor 10.

[0059] In one embodiment, the number of stator slots 213 is Q, where 15 ≤ Q ≤ 18.

[0060] A greater number of stator slots 213 can reduce magnetic reluctance and increase magnetic flux, thus improving the efficiency of the permanent magnet motor 10; it can also distribute magnetic flux more evenly, reducing cogging effect and helping to reduce cogging torque; it can improve the waveform quality of the back EMF, making it closer to an ideal sinusoidal waveform; and it can improve magnetic flux distribution, reducing torque ripple caused by inter-pole interaction. However, a greater number of slots may also require more space, increasing the size or weight of the permanent magnet motor 10, thereby reducing power density and increasing manufacturing costs. When 15 ≤ Q ≤ 18, it is possible to optimize magnetic flux distribution, improve the waveform quality of the back EMF, and reduce cogging torque and torque ripple while controlling the size and manufacturing cost of the permanent magnet motor 10.

[0061] In one embodiment, a plurality of permanent magnets 120 form 2P magnetic poles in the circumferential direction of the rotor core 110, where 10 ≤ 2P ≤ 12.

[0062] A larger number of magnetic poles increases the complexity of the magnetic circuit, but also increases the total cross-sectional area of ​​the circuit, which helps increase the magnetic flux. It can better distribute the magnetic flux, thus reducing abrupt changes in flux density, reducing cogging effect, and helping to reduce cogging torque. It can improve the waveform quality of the back EMF, making it closer to an ideal sinusoidal waveform. It can improve flux distribution and reduce torque ripple caused by inter-pole interaction. However, more slots may require more space, increasing the size or weight of the permanent magnet motor 10, thereby reducing power density and increasing manufacturing costs. Moreover, as the number of magnetic poles increases, the synchronous speed of the permanent magnet motor 10 decreases, resulting in a lower maximum speed. When 10 ≤ 2P ≤ 12, it is possible to optimize flux distribution, improve the waveform quality of the back EMF, reduce cogging torque and torque ripple, while controlling the size and manufacturing cost of the permanent magnet motor 10 and ensuring the synchronous speed of the permanent magnet motor 10.

[0063] In one implementation, Q / 2P = 3 / 2.

[0064] By limiting the ratio of the number of stator slots 213 to the number of magnetic poles in the motor rotor 100 to 3 / 2, it is possible to optimize the magnetic flux distribution, improve the waveform quality of the back EMF, reduce cogging torque and torque ripple, while controlling the size and manufacturing cost of the permanent magnet motor 10 and ensuring the synchronous speed of the permanent magnet motor 10. In one embodiment, the number of stator slots 213 is 15, and the number of magnetic poles in the motor rotor 100 is 10. In another embodiment, the number of stator slots 213 is 18, and the number of magnetic poles in the motor rotor 100 is 12.

[0065] In one implementation, 50 ≤ N ≤ 140.

[0066] The larger the number of winding turns N on each stator tooth 212, the higher the back electromotive force (EMF) and the higher the winding resistance. This reduces the current of the permanent magnet motor 10 at a given voltage, thus helping to reduce copper losses (I²R losses) and improve the efficiency of the permanent magnet motor 10. However, when the number of winding turns N increases to a certain value, the unit magnetic flux of the permanent magnet motor 10 decreases, and its demagnetization resistance also decreases. When 50 ≤ N ≤ 140, the back EMF of the permanent magnet motor 10 can be increased, improving its energy efficiency while ensuring its demagnetization resistance.

[0067] The present invention also proposes a compressor, which includes a permanent magnet motor 10. The specific structure of the permanent magnet motor 10 is as described in the above embodiments. Since the compressor in the technical solution of the present invention 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.

[0068] This invention also proposes a refrigeration device, which includes a compressor. The specific structure of the compressor is as described in the above embodiments. Refrigeration devices can be categorized into compression refrigeration devices, absorption refrigeration devices, vapor jet refrigeration devices, heat pump refrigeration devices, and electric heating refrigeration devices, etc. Refrigeration devices mainly consist of a compressor, expansion valve, evaporator, condenser, accessories, and piping. Examples include refrigerators and air conditioners. Since the compressor in this invention employs all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon further here.

[0069] 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 permanent magnet motor, characterized in that, The permanent magnet motor includes: An electric motor rotor includes a rotor core and permanent magnets. The rotor core has multiple permanent magnet slots spaced apart along its circumference. The permanent magnets are embedded in the permanent magnet slots. The length of the permanent magnets along the axial direction of the rotor core is L1. A motor stator is sleeved on the outer periphery of the motor rotor. The motor 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. The stator winding is wound on the stator teeth. The number of turns of winding on each stator tooth is N. Wherein, 0.12≤N / (Q×L1)≤0.

2.

2. The permanent magnet motor as described in claim 1, characterized in that, The rotor core has an axial length of L2, and the stator core has an axial length of L3, where 0mm ≤ L2 - L3 ≤ 2mm.

3. The permanent magnet motor as described in claim 2, characterized in that, 0mm≤L1-L3≤1mm.

4. The permanent magnet motor as described in claim 2, characterized in that, 20mm≤L1≤50mm; And / or, 20mm≤L2≤50mm; And / or, 20mm≤L3≤50mm.

5. The permanent magnet motor as described in claim 1, characterized in that, The permanent magnets form 2P magnetic poles in the circumferential direction of the rotor core, where Q and 2P satisfy: 1 ​​< Q / 2P < 3.

6. The permanent magnet motor as described in claim 5, characterized in that, 15≤Q≤18。 7. The permanent magnet motor as described in claim 5, characterized in that, 10≤2P≤12。 8. The permanent magnet motor as described in claim 5, characterized in that, Q / 2P = 3 / 2.

9. The permanent magnet motor as described in claim 1, characterized in that, 50≤N≤140。 10. A compressor, characterized in that, Including the permanent magnet motor as described in any one of claims 1 to 9.

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

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