Permanent magnet motor, compressor and refrigeration equipment

Abstract

The utility model discloses a permanent magnet motor, a compressor and refrigeration equipment, and relates to the refrigeration equipment technology field, the permanent magnet motor comprises a motor rotor and a motor stator, the motor rotor comprises a rotor iron core and a permanent magnet, and the permanent magnet is embedded in a permanent magnet groove; 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 utility model, N, Q and L1 meet the condition that N / (Q * L1) is more than or equal to 0.12 and less than or equal to 0.2 by adjusting the relationship among the number of turns N of the windings on the single stator tooth of the permanent magnet motor, the number Q of the stator slots and the length L1 of the permanent magnets along the axial direction of the rotor core, so that the permanent magnet motor can meet the requirement of the operation range under the maximum pressure difference, and the operation efficiency is improved. Counter potential of the permanent magnet motor is improved, and energy efficiency of the permanent magnet motor is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration equipment, and particularly relates to a permanent magnet motor, a compressor and a refrigeration equipment. Background Art

[0002] A permanent magnet motor is a high-efficiency and high-performance motor, which is widely used in fields such as electric vehicles, robots, and wind power generation. The energy efficiency of a permanent magnet motor is affected by multiple factors, including motor design, material selection, temperature management, and control strategies. Among them, the characteristics of the back electromotive force have a direct impact on the energy efficiency of the motor. In addition, broadening the operating range is also crucial for improving the adaptability and flexibility of the motor. In some application scenarios, such as electric vehicles, the motor needs to operate efficiently within a wide speed range. However, when the motor speed is too high, the back electromotive force may approach or exceed the power supply voltage, which will limit the acceleration ability of the motor and the torque output at high speeds. 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 of the Utility Model

[0003] The main purpose of the utility model is to propose a permanent magnet motor, a compressor and a refrigeration equipment, aiming to improve the back electromotive force of the permanent magnet motor and enhance the energy efficiency of the permanent magnet motor while meeting the operating range requirements under the maximum pressure difference.

[0004] To achieve the above purpose, the permanent magnet motor proposed by the utility model includes:

[0005] A motor rotor, including a rotor core and permanent magnets. The rotor core is provided with a plurality of permanent magnet slots at intervals along its circumference, and 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 L 1 ;

[0006] A motor stator, 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 the stator teeth are arranged at intervals along the inner circumference of the stator yoke. A stator slot is formed between two adjacent stator teeth. The number of the stator slots is Q; the stator winding is wound around the stator teeth, and the number of turns of the winding on each stator tooth is N;

[0007] Wherein, 0.12 ≤ N / (Q × L 1 ) ≤ 0.2.

[0008] In an embodiment, the length of the rotor core along its axial direction is L 2 , the length of the stator core along its axial direction is L 3 , 0mm ≤ L 2 - L 3 ≤ 2mm.

[0009] In one embodiment, 0 mm ≤ L 1 -L 3 ≤ 1 mm.

[0010] In one embodiment, 20 mm ≤ L 1 ≤ 50 mm.

[0011] In one embodiment, 20 mm ≤ L 2 ≤ 50 mm.

[0012] In one embodiment, 20 mm ≤ L 3 ≤ 50 mm.

[0013] In one embodiment, a plurality of the permanent magnets form 2P magnetic poles in the circumferential direction of the rotor core, and Q and 2P satisfy: 1 < Q / 2P < 3.

[0014] In one embodiment, 15 ≤ Q ≤ 18.

[0015] In one embodiment, 10 ≤ 2P ≤ 12.

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

[0017] In one embodiment, 50 ≤ N ≤ 140.

[0018] The present utility model further provides a compressor, including the aforementioned permanent magnet motor.

[0019] The present utility model further provides a refrigeration device, including the aforementioned compressor.

[0020] The technical solution of the present utility model adjusts the relationship between 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 L of the permanent magnet along the axial direction of the rotor core 1 such that N, Q, and L 1 satisfy: 0.12 ≤ N / (Q × L 1 ) ≤ 0.2. The permanent magnet motor can meet the operation range requirements under the maximum pressure difference while improving the back electromotive force of the permanent magnet motor and enhancing the energy efficiency of the permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0022] Figure 1 Structural schematic diagram of an embodiment of the permanent magnet motor provided by the present utility model;

[0023] Figure 2 is Figure 1 partial enlarged view at position A in;

[0024] Figure 3 Structural schematic diagram of an embodiment of the compressor provided by the present utility model;

[0025] Figure 4 is N / (Q×L 1 ) and the relationship curve of the permanent magnet motor speed and the compressor COP.

[0026] Explanation of the reference numerals in the drawings:

[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, functional features and advantages of the object of the present utility model will be further described in conjunction with the embodiments with reference to the drawings. Specific embodiments

[0029] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0030] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0031] In addition, if the embodiments of the present utility model involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0032] The present utility model provides a permanent magnet motor 10.

[0033] Please refer to Figure 1 , in an embodiment of the present utility model, 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. A plurality of permanent magnet slots 111 are provided at intervals along the circumference of the rotor core 110. The permanent magnets 120 are embedded in the permanent magnet slots 111. The length of the permanent magnets 120 along the axial direction of the rotor core 110 is L 1 ; The motor stator 200 is sleeved on the outer periphery of the motor rotor 100. The motor 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. A plurality of stator teeth 212 are provided at intervals 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 around the stator teeth 212. The number of turns of the winding on each stator tooth 212 is N; Wherein, 0.12 ≤ N / (Q × L 1 ) ≤ 0.2.

[0034] Specifically, the permanent magnet motor 10 includes a motor rotor 100 and a motor stator 200. The motor stator 200 is sleeved on the outer periphery of the motor rotor 100. The motor stator 200 includes a stator core 210 and a stator winding 220, which is used to generate a rotating magnetic field. The stator core 210 is formed by laminating silicon steel sheets. The stator core 210 includes a stator yoke 211 and stator teeth 212. The stator yoke 211 is annular, and a plurality of stator teeth 212 are arranged at intervals along the circumferential direction of the stator yoke 211 on the inner side of the stator yoke 211. A stator slot 213 is defined between adjacent stator teeth 212. 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 will be generated, and the permanent magnet 120 on the motor rotor 100 interacts with the 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 a permanent magnet 120. The permanent magnet 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 realize the normal operation of the permanent magnet motor 10. The rotor core 110 is made of high-permeability material or laminated silicon steel sheets, has high magnetic permeability, and has high structural strength, which is convenient for processing. The permanent magnet 120 is embedded in the permanent magnet slot 111. When embedding, it is required that the permanent magnets 120 under the same magnetic pole face the same polarity in the direction of the outer periphery of the motor rotor 100, and at the same time, it is required that the magnetic properties of the permanent magnets 120 of adjacent magnetic poles are opposite. A plurality of magnetic poles are alternately distributed in the circumferential direction of the rotor core 110 according to N poles and S poles. The permanent magnet slot 111 can be linear, arc-shaped, "U"-shaped, "V"-shaped or "W"-shaped. Among them, a corresponding linear or arc-shaped permanent magnet 120 is embedded in the linear or arc-shaped permanent magnet slot 111; the "U"-shaped, "V"-shaped or "W"-shaped permanent magnet slots 111 are formed by combining and embedding a plurality of linear 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 a vernier caliper, a digital micrometer, a straight ruler or a tape measure, etc. For example, place the permanent magnet 120 on a platform, use the inner and outer measuring jaws of a vernier caliper to clamp both ends of the permanent magnet 120 along the axial direction of the rotor core 110, and read the measured reading. Please refer to Figure 1 and Figure 2 , the number of turns of wire N on each stator tooth 212 and the number of stator slots 213 Q can be directly observed. Among them, Figure 2 the number of turns of wire in the wire frame is the number of turns of wire N on one stator tooth 212.

[0036] The effective value E of the induced electromotive force per phase of the stator winding 220 can be expressed by the following formula: E = 4.44KfN 1φ. Wherein, E is the effective value of the induced electromotive force per phase (volt); K is the winding coefficient of the stator winding 220 (less than 1), which depends on the specific structure of the winding; f is the frequency of the induced electromotive force of the stator winding 220 (hertz), usually equal to the frequency of the power supply; N 1 is the number of turns of the coils connected in series in each phase of the stator winding 220; φ is the magnetic flux per pole of the rotating magnetic field, that is, the maximum value of the alternating magnetic flux passing through the stator winding 220 (weber).

[0037] It can be known that the number of turns N of the winding on each stator tooth 212, the number Q of stator slots 213, and the length L of the permanent magnet 120 along the axial direction of the rotor core 110 1 will affect the back electromotive force generated during the operation of the permanent magnet motor 10. Among them, the number of turns N of the winding directly affects the change rate of the magnetic flux linkage, and thus affects the magnitude of the back electromotive force. It can be understood that for each additional turn of the winding, the magnetic flux linkage passing through the stator winding 220 will also increase accordingly. According to Faraday's law of electromagnetic induction, the change rate of magnetic flux is proportional to the induced electromotive force. Therefore, increasing the number of turns of the stator winding 220 will increase the induced back electromotive force. Since the resistance of the stator winding 220 increases with the increase of the number of turns, it 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 can accommodate more stator windings 220, thereby improving the magnetic field distribution to obtain a smoother magnetic field distribution, which helps to improve the efficiency of the permanent magnet motor 10. Therefore, the number of stator slots 213 more affects the magnetic field distribution inside the permanent magnet motor 10 and the physical layout of the stator winding 220, and indirectly affects the back electromotive force.

[0039] Increasing the length L of the permanent magnet 120 along the axial direction of the rotor core 110 1 usually increases the magnetic flux density and the change rate of the magnetic flux linkage. At the same rotational speed, more magnetic flux passes through the stator winding 220, thereby generating a larger back electromotive force. A higher back electromotive force can help the permanent magnet motor 10 operate more efficiently at a high voltage, and thus can improve 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. The back electromotive force is the voltage generated by cutting the magnetic induction line when the permanent magnet motor 10 rotates, and its magnitude is proportional to the rotational speed. As the rotational speed increases, the back electromotive force increases, resulting in a decrease 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 electromotive force may approach or exceed the power supply voltage, which will limit the acceleration ability of the permanent magnet motor 10 and the torque output at high speeds.

[0041] According to the verification of experimental results, by adjusting the number of turns N of the winding on each stator tooth 212, the number Q of stator slots 213, and the length L of the permanent magnet 120 along the axial direction of the rotor core 110 1 The relationship between them is such that N, Q, and L 1 Satisfy: 0.12 ≤ N / (Q × L 1 ) ≤ 0.2. The permanent magnet motor 10 can, while meeting the operating range requirements under the maximum pressure difference, improve the back electromotive force of the permanent magnet motor 10 and increase the energy efficiency of the permanent magnet motor 10.

[0042] Please refer to Table 1 and Figure 4 , as N / (Q × L 1 ) increases, the COP (Coefficient of Performance) of the compressor also increases. When N / (Q × L 1 ) ≥ 0.12, the COP of the compressor exceeds 412.0%, the back electromotive force of the permanent magnet motor 10 is improved, and the energy efficiency of the permanent magnet motor 10 is increased. However, as N / (Q × L 1 ) increases, the maximum speed of the permanent magnet motor 10 under the maximum pressure difference decreases. When N / (Q × L 1 ) ≥ 0.2, its maximum speed has dropped to 120 rps, and the operating range of the permanent magnet motor 10 shrinks. Therefore, when 0.12 ≤ N / (Q × L 1 ) ≤ 0.2, the maximum speed of the permanent magnet motor 10 under the maximum pressure difference is between 120 rps and 160 rps, which can meet the operating range requirements of the permanent magnet motor 10 under the maximum pressure difference. At the same time, the COP of the compressor is between 412.0% and 419.0%, the back electromotive force of the permanent magnet motor 10 is improved, and the energy efficiency of the permanent magnet motor 10 is increased.

[0043] Table 1: Relationship table of N / (Q × L 1 ) with the speed of the permanent magnet motor and the COP of the compressor

[0044]

[0045] In an embodiment, please refer to Figure 3 , the length of the rotor core 110 along its axial direction is L 2 , the length of the stator core 210 along its axial direction is L 3 , 0 mm ≤ L 2 - L 3 ≤ 2 mm.

[0046] The motor rotor 100 includes a rotor core 110 formed by laminating silicon steel sheets. The length of the motor rotor 100 along its axial direction is the thickness of its multiple layers of silicon steel sheets stacked together. Similarly, the motor stator 200 includes a stator core 210 formed by laminating silicon steel sheets. The length of the motor stator 200 along its axial direction is the thickness of its multiple layers of silicon steel sheets stacked together. 0mm ≤ L 2 -L 3 ≤ 2mm, which means that the length of the rotor core 110 along its axial direction is not less than the length of the stator core 210 along its axial direction, that is, the thickness of the multiple layers of silicon steel sheets of the motor rotor 100 stacked together is not less than the thickness of the multiple layers of silicon steel sheets of the motor stator 200. Then, the amount of permanent magnets 120 placed in the rotor core 110 will be large, and the magnetic flux generated by the motor rotor 100 will increase, thereby increasing the permanent magnet torque of the permanent magnet motor 10, improving the output capacity of the permanent magnet motor 10, and improving the performance of the permanent magnet motor 10.

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

[0048] In an embodiment, the length of the permanent magnet 120 along the axial direction of the rotor core 110 is L 1 , and the length of the stator core 210 along its axial direction is L 3 , 0mm ≤ L 1 -L 3 ≤ 1mm.

[0049] 0mm ≤ L 1 -L 3 ≤ 1mm, which 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 rotor core 110 along its axial direction, that is, L 2 ≥ L 1 ≥ L 3 . 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 change rate of the magnetic flux linkage and the magnetic flux density will increase. At the same rotational speed, more magnetic flux passes through the stator winding 220, thereby generating a larger back electromotive force and output torque, and thus the output power and efficiency of the permanent magnet motor 10 during high-speed operation can be improved.

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

[0051] In one embodiment, the length of the permanent magnet 120 along the axis of the rotor core 110 is L 1 , 20 mm ≤ L 1 ≤ 50 mm.

[0052] As the length of the permanent magnet 120 increases, the permanent magnet 120 can provide more magnetic flux, thereby increasing the magnetic flux linkage passing through the stator winding 220. More magnetic flux passes through the stator winding 220 when the rotor rotates, so the rate of change of the magnetic flux linkage, the magnetic flux density, and the output torque of the permanent magnet motor 10 will also increase. However, a longer permanent magnet 120 requires a better cooling system to prevent the degradation of magnetic properties due to excessive temperature. The permanent magnet 120 is expensive, which will increase the material cost and make the assembly process more complicated. At the same time, the size of the motor stator 200 sleeved on the outer periphery of the motor rotor 100 will also increase, making the size of the permanent magnet motor 10 larger, which is not only not conducive to the lightweight of the permanent magnet motor 10, but also increases the manufacturing cost. When 20 mm ≤ L 1 ≤ 50 mm, it can not only ensure that the permanent magnet 120 can provide sufficient magnetic flux, but also control the overall size of the permanent magnet motor 10 to be smaller and reduce the total production cost.

[0053] In one embodiment, please refer to Figure 3 , the length of the rotor core 110 along its axis is L 2 , 20 mm ≤ L 2 ≤ 50 mm.

[0054] L 1 and L 2 can both take the minimum value of 20 mm, or both take the maximum value of 50 mm. They can also take any value between 20 mm and 50 mm under the condition of satisfying L 2 ≥ L 1 so as to not only ensure that the permanent magnet 120 can provide sufficient magnetic flux, but also control the overall size of the permanent magnet motor 10 to be smaller and reduce the total production cost.

[0055] In one embodiment, please refer to Figure 3 , the length of the stator core 210 along its axis is L 3 , 20 mm ≤ L 3 ≤ 50 mm.

[0056] L 1 , L2 and L 3 can simultaneously take the minimum value of 20 mm, or can simultaneously take the maximum value of 50 mm, or can also take any value between 20 mm and 50 mm when satisfying 2 ≥L 1 ≥L 3 In this case, so as to not only ensure that the permanent magnet 120 can provide sufficient magnetic flux, but also control the overall size of the permanent magnet motor 10 to be relatively small and reduce the total production cost.

[0057] In one embodiment, please refer to Figure 1 , a plurality of 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 is the number of magnetic poles formed in the circumferential direction of the rotor core 110, and P is the number of pole pairs of the motor rotor 100. Different ratios of Q / 2P can have different effects on the waveform quality of the back electromotive force and the ripple torque, thus having an important impact on the back electromotive force characteristics and energy efficiency of the permanent magnet motor 10. Therefore, in order to reduce the tooth harmonic magnetic field and torque ripple, the number of stator slots 213 and the number of pole pairs are usually optimized. The ratio of Q / 2P determines the magnetic field interaction between the motor stator 200 and the motor rotor 100. Different slot ratios will affect the fundamental wave flux density distribution of the permanent magnet motor 10, and further affect the performance of the motor. When there is no good cooperation between the two, higher tooth harmonics may be generated, resulting in 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 flux density distribution to improve the output capacity of the motor and reduce the iron loss. When 1 < Q / 2P < 3, there is a better ratio between the number of stator slots 213 and the number of pole pairs, which can optimize the flux density distribution, reduce losses and torque ripple, thus 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, and 15 ≤ Q ≤ 18.

[0060] A larger number of stator slots 213 can reduce the reluctance, increase the magnetic flux, and contribute to improving the efficiency of the permanent magnet motor 10; it can evenly distribute the magnetic flux, reduce the cogging effect, and help reduce the cogging torque; it can improve the waveform quality of the back electromotive force, making it closer to an ideal sine wave; it can improve the magnetic flux distribution and reduce the torque ripple caused by the interaction between magnetic poles. However, at the same time, it may require more space due to the larger number of slots, thereby increasing the volume or weight of the permanent magnet motor 10, reducing the power density, and increasing the manufacturing cost. When 15 ≤ Q ≤ 18, it is possible to control the volume and manufacturing cost of the permanent magnet motor 10 while optimizing the magnetic flux distribution, improving the waveform quality of the back electromotive force, reducing the cogging torque, and reducing the torque ripple.

[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 can increase the complexity of the magnetic circuit, but at the same time increase the total cross-sectional area of the magnetic circuit, which helps to increase the magnetic flux; it can better disperse the magnetic flux, thereby reducing the sudden change of the magnetic flux density, reducing the cogging effect, and helping to reduce the cogging torque; it can improve the waveform quality of the back electromotive force, making it closer to an ideal sine wave; it can improve the magnetic flux distribution and reduce the torque ripple caused by the interaction between magnetic poles. However, at the same time, it may require more space due to the larger number of slots, thereby increasing the volume or weight of the permanent magnet motor 10, reducing the power density, and increasing the manufacturing cost. Moreover, as the number of magnetic poles increases, the synchronous speed of the permanent magnet motor 10 will decrease, resulting in a lower maximum speed of the permanent magnet motor 10. When 10 ≤ 2P ≤ 12, it is possible to control the volume and manufacturing cost of the permanent magnet motor 10 while optimizing the magnetic flux distribution, improving the waveform quality of the back electromotive force, reducing the cogging torque, and reducing the torque ripple, and ensuring the synchronous speed of the permanent magnet motor 10.

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

[0064] By limiting the ratio of the number of stator slots 213 to the number of magnetic poles of the motor rotor 100 to 3 / 2, it is possible to control the volume and manufacturing cost of the permanent magnet motor 10 while optimizing the magnetic flux distribution, improving the waveform quality of the back electromotive force, reducing the cogging torque, and reducing the torque ripple, 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 of the motor rotor 100 is 10. In another embodiment, the number of stator slots 213 is 18, and the number of magnetic poles of the motor rotor 100 is 12.

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

[0066] The larger the number of turns N of the winding on each stator tooth 212, the higher the back electromotive force, and the winding resistance also increases accordingly, thereby reducing the current of the permanent magnet motor 10 under a given voltage, which helps to reduce the copper loss (I2R loss) and improve the efficiency of the permanent magnet motor 10. However, when the number of turns N of the winding increases to a certain value, the magnetic flux per unit of the permanent magnet motor 10 decreases instead, and its demagnetization resistance also decreases. When 50 ≤ N ≤ 140, the back electromotive force of the permanent magnet motor 10 can be increased, the energy efficiency of the permanent magnet motor 10 can be improved, and at the same time, the demagnetization resistance of the permanent magnet motor 10 can be ensured.

[0067] The present utility model also provides a compressor, which includes a permanent magnet motor 10. The specific structure of the permanent magnet motor 10 refers to the above-mentioned embodiments. Since the compressor in the technical solution of the present utility model adopts all the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated here one by one.

[0068] The present utility model also provides a refrigeration device, which includes a compressor. The specific structure of the compressor refers to the above-mentioned embodiments. Refrigeration devices can be divided into compression refrigeration devices, absorption refrigeration devices, steam jet refrigeration devices, heat pump refrigeration devices, electrothermal refrigeration devices, etc. The refrigeration device mainly consists of a compressor, an expansion valve, an evaporator, a condenser, and accessories and pipelines. Such as refrigerators, air conditioners, etc. Since the compressor in the technical solution of the present utility model adopts all the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated here one by one.

[0069] The above is only an exemplary embodiment of the present utility model, and does not limit the patent scope of the present utility model. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present utility model.

Claims

1. A permanent magnet motor, characterized in that: The permanent magnet motor comprises: The motor rotor comprises a rotor core and permanent magnets, wherein the rotor core is provided with a plurality of permanent magnet slots spaced apart along its circumference, 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; A motor stator is sleeved on the outer circumference 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, a plurality of stator teeth are arranged at intervals along the inner circumference of the stator yoke, a stator slot is formed between two adjacent stator teeth, and the number of stator slots is Q; the stator winding is wound on the stator teeth, and the number of winding turns on each stator tooth is N; Among them, 0.12≤N / (Q×L1)≤0.

2.

2. The permanent magnet motor according to claim 1, characterized in that: The length of the rotor core along the axial direction is L2, and the length of the stator core along the axial direction is L3, 0mm≤L2-L3≤2mm.

3. The permanent magnet motor according to claim 2, characterized in that: 0mm≤L1-L3≤1mm.

4. The permanent magnet motor according to claim 2, characterized in that: 20mm≤L1≤50mm; and / or, 20 mm ≤ L2 ≤ 50 mm; And / or, 20mm≤L3≤50mm.

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

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

9. The permanent magnet motor according to claim 1, characterized in that: 50≤N≤140。 10. A compressor, characterized in that: It comprises a permanent magnet motor as claimed in any one of claims 1 to 9.

11. A refrigeration device, characterized in that: Comprising the compressor of claim 10.

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