Rotor structure and motor

Abstract

The invention provides a rotor structure and a motor, magnet grooves comprise two first magnet grooves and two second magnet grooves which are communicated with each other, the two second magnet grooves are located between the two first magnet grooves, and two sides of a D shaft of a magnetic pole are respectively provided with one first magnet groove and one second magnet groove; a first V-shaped groove with an opening deviating from the central point of the rotor core is formed between the two second magnet grooves, and a second V-shaped groove with an opening facing the central point of the rotor core is formed between the adjacent first magnet groove and the second magnet groove; wherein a plurality of magnetic barrier holes are formed between the first V-shaped grooves and the outer peripheral wall of the rotor core, and a plurality of auxiliary grooves are formed in the outer peripheral wall, corresponding to the second V-shaped grooves, of the rotor core; while the high salient pole ratio is ensured, the cogging torque is reduced, magnetic flux leakage and higher harmonics are inhibited, and meanwhile, the power density and efficiency of the motor are not influenced.

Description

Technical Field

[0001] This invention belongs to the field of compressor technology, specifically relating to a rotor structure and a motor. Background Technology

[0002] Currently, the permanent magnet motors used in the variable frequency compressor industry generally employ either straight-line or V-shaped magnet slots on the rotor. Figure 1 and Figure 2 As shown.

[0003] The use of a straight magnet slot is mainly due to its advantages of simple structure, low cost and ease of processing. However, the magnets are arranged in a straight strip shape, resulting in uneven distribution of magnetic flux density in the air gap, a high leakage coefficient, and insufficient utilization of the rotor's effective magnetic flux. The torque pulsation is large, the cogging torque is obvious, and it is easy to generate vibration and noise. The ability to control weak magnetic fields is insufficient, the efficiency drops significantly at high speeds, the increase in motor power density is limited, and the size cannot be reduced sufficiently to meet the current market demand for small and efficient compressors.

[0004] The main consideration for using V-shaped magnet slots is to increase the salient pole ratio of the motor to a certain extent, improve the magnetic reluctance torque, and increase the power density of the motor. At the same time, by adjusting the angle of the magnet slots, the concentration of air gap magnetic flux is optimized. However, each pole magnet is still arranged in a single row, and the magnetic flux uniformity and the ability to optimize the cogging torque are limited. For high-speed operation or weak field speed expansion conditions, the performance improvement is not sufficient, and the cost is also significantly higher than that of straight magnet slots.

[0005] In summary, the current structural design of magnet slots in the industry cannot adequately balance the demands for low cost and high performance. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention provides a rotor structure and motor that can reduce cogging torque, suppress leakage flux and high-order harmonics while ensuring a high salient pole ratio, and simultaneously ensure that the power density and efficiency of the motor are not affected.

[0007] The technical effects to be achieved by this invention are realized through the following technical aspects: This invention provides a rotor structure, including a rotor core; The rotor core has multiple magnetic poles distributed circumferentially, and each magnetic pole is provided with a magnet slot. The magnet slot includes two connected first magnet slots and two second magnet slots, with the two second magnet slots located between the two first magnet slots, and so that there is one first magnet slot and one second magnet slot on each side of the D-axis of the magnetic pole. A first V-shaped groove with an opening away from the center point of the rotor core is formed between the two second magnet slots, and a second V-shaped groove with an opening facing the center point of the rotor core is formed between adjacent first magnet slots and second magnet slots. In this configuration, a plurality of magnetic barrier holes are provided between the first V-shaped groove and the outer peripheral wall of the rotor core, and a plurality of auxiliary grooves are formed on the outer peripheral wall of the rotor core corresponding to the second V-shaped groove.

[0008] In some implementations, the outer edge of the rotor core corresponding to the second V-groove includes a first arc segment, a first tangent edge, and a second tangent edge connected in sequence, with the first arc segment close to the D-axis; The number of auxiliary slots is two, including a first auxiliary slot and a second auxiliary slot; The first auxiliary groove is formed on the first arc segment, and the second auxiliary groove is formed between the first arc segment and the first tangent edge.

[0009] In some implementations, the minimum distance between the first magnet groove and the second tangent edge is set to H1, the radius of the first auxiliary groove is set to R1, and the radius of the second auxiliary groove is set to R2. H1, R1, and R2 satisfy the following relationship: 0.25 mm < (R1 + R2) / H1 ≤ 1.5 mm; The R1 and R2 satisfy the following relationship: 0.3 mm ≤ R1 + R2 < 1.8 mm.

[0010] In some implementations, the thickness of the first magnet groove in the axial direction is H2, and the thickness of the second magnet groove in the axial direction is H3. The following relationship exists between H2 and H3: 1.2 * H2 ≥ H3 ≥ H2.

[0011] In some implementations, the minimum distance between the first magnet groove and the second tangent edge is set to H1, and the minimum distance between the magnetic barrier hole and the first V-groove is set to H4; The following relationship exists between H1 and H4: 1.1 * H1 ≥ H4 ≥ 0.8 * H1.

[0012] In some implementations, the minimum distance between the first magnet groove and the second tangent edge is set to H1, the thickness of the first magnet groove in the axial direction is set to H2, and the thickness of the magnetic bridge between two adjacent magnetic poles in the radial direction is set to H5. The following relationship is satisfied between H1, H2 and H5: 0.8 mm ≤ H5 < (H2-H1) / 2 mm.

[0013] In some implementations, the included angle of the first V-groove is θ1, the included angle of the second V-groove is θ2, and the included angle between the first magnet groove and the first tangent is θ3. The θ1 satisfies the following relationship: 150°<θ1<170°; The θ1 and θ2 satisfy the following relationship: θ1-θ2<10°; The θ2 and θ3 satisfy the following relationship: θ2 + θ3 < 180°.

[0014] In some implementations, the length of the second magnet slot in the radial direction is L1, and the length of the first magnet slot in the radial direction is L2; The L1 and L2 satisfy the following relationship: 2*L2≥L1≥L2.

[0015] In some implementations, the length of the first magnet groove in the radial direction is L2, the minimum distance between the first magnet groove and the second tangent is H1, and the angle between the first magnet groove and the first tangent is θ3. The L2, H1, and θ3 satisfy the following relationship: 0.45*L3*sin(θ3) < H1 < 0.65*L3*sin(θ3).

[0016] In another aspect, the present invention also provides an electric motor comprising the rotor structure described in any of the preceding claims.

[0017] In summary, the present invention has at least the following advantages: 1. The rotor structure provided by this invention, by designing a first V-shaped slot with its opening facing away from the center point of the rotor core and a second V-shaped slot with its opening facing the center point of the rotor core, can improve the saliency ratio and reluctance torque compared to the problems of low efficiency and large torque ripple of the straight magnet slot. This reduces the motor current and losses while achieving the same torque, thereby improving motor efficiency and reducing load torque ripple. In addition, compared to the problems of low utilization and high cost of the V-shaped magnet slot, this invention can reduce the total number of magnets while ensuring performance, which is equivalent to improving the utilization rate. This makes the overall cost much lower than that of the traditional V-shaped magnet slot and close to that of the straight magnet slot.

[0018] 2. The motor provided by the present invention, after applying the above-mentioned rotor structure, can improve the harmonic content of the back EMF of the motor, improve the noise and vibration of the motor to a certain extent, and increase the stability of the electronic control. Attached Figure Description

[0019] Figure 1 A schematic diagram of the linear magnet slot rotor mentioned in the background art; Figure 2A schematic diagram of the V-shaped magnet slot rotor mentioned in the background art; Figure 3 A schematic diagram of the rotor core provided in Embodiment 1 of the present invention; Figure 4 and Figure 5 This is a schematic diagram of the rotor core provided in Embodiment 2 of the present invention; Figure 6 A comparison diagram of the three schemes provided in Embodiment 2 of the present invention; Figure 7 This is a comparison diagram of the no-load back EMF waveform provided in Embodiment 2 of the present invention; Figure 8 This is a comparison diagram of the cogging torque waveform provided in Embodiment 2 of the present invention; Figure 9 This is a comparison diagram of the load torque waveform provided in Embodiment 2 of the present invention; Marked in the image: 100. Rotor core; 110. First arc segment; 120. First tangent edge; 130. Second tangent edge; 200. First magnet slot; 300. Second magnet slot; 400. First V-groove; 500, Second V-groove; 600. Magnetic barrier hole; 700, Auxiliary slot; 710, First auxiliary slot; 720, Second auxiliary slot. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more comprehensive description will be given below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0021] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] Example 1: Please see Figure 3 A rotor structure includes a rotor core 100, the rotor core 100 having multiple magnetic poles distributed circumferentially, each magnetic pole having a magnet slot.

[0025] In a permanent magnet motor, the magnetic pole is the basic unit for the rotor to generate a magnetic field, while the magnet slot is the physical carrier that fixes the magnet. The design of the magnet slot is matched with the magnetic field requirements of the magnetic pole. In one example, the rotor core 100 has six magnetic poles distributed circumferentially, and each magnetic pole is provided with a magnet slot.

[0026] The magnet slot includes two connected first magnet slots 200 and two second magnet slots 300. The two second magnet slots 300 are located between the two first magnet slots 200, and there are one first magnet slot 200 and one second magnet slot 300 on each side of the D-axis of the magnetic pole.

[0027] Here, two first magnet slots 200 and two second magnet slots 300 together form a magnet slot. The two first magnet slots 200 are located at the two ends of the magnet slot, while the two second magnet slots 300 are located in the middle of the magnet slot. The D-axis is the center line that passes radially through the magnetic pole. There is a first magnet slot 200 and a second magnet slot 300 on each side of the D-axis of the magnetic pole.

[0028] Among them, a first V-shaped groove 400 with an opening away from the center point of the rotor core 100 is formed between the two second magnet grooves 300, and a second V-shaped groove 500 with an opening facing the center point of the rotor core 100 is formed between adjacent first magnet grooves 200 and second magnet grooves 300.

[0029] Here, it is equivalent to each magnetic pole having a first V-shaped slot 400 and two second V-shaped slots 500, with the opening directions of the first V-shaped slot 400 and the second V-shaped slots 500 being opposite. Considering the two second magnetic slots 300 located on both sides of the D-axis as a single unit, forming the first V-shaped slot 400, and then placing the two magnet segments within the two second magnetic slots 300 of the first V-shaped slot 400, from an electromagnetic perspective, the principle is consistent with the traditional V-shaped magnetic slot structure. Therefore, it possesses the high saliency ratio technical characteristics of a V-shaped structure, while also having a larger motor power density, thus improving the motor's output capability.

[0030] To reduce the problem of insufficient magnet utilization due to the large depth of the traditional V-shaped magnet groove on the D-axis, a second V-shaped groove 500 is formed on one side of the D-axis. The magnet on the D-axis side is divided into two segments and installed in the first magnet groove 200 and the second magnet groove 300 of the second V-shaped groove 500. The opening between the two magnet segments is opposite to the opening between the two magnet segments installed in the first V-shaped groove 400. In this way, while maintaining the distance between the magnets on both sides of the Q-axis, the magnets are used more effectively, the total number of magnets used is reduced, and a smaller current can be used to achieve the same load torque.

[0031] Furthermore, a plurality of magnetic barrier holes 600 are provided between the first V-groove 400 and the outer peripheral wall of the rotor core 100, and a plurality of auxiliary grooves 700 are formed on the outer peripheral wall of the rotor core 100 corresponding to the second V-groove 500.

[0032] Specifically, the first V-groove 400 is distributed on both sides of the D-axis. Magnetic barrier holes 600 are opened between the first V-groove 400 and the outer peripheral wall of the rotor core 100. This can effectively block the leakage magnetic path, allowing more magnetic flux to pass through the air gap and couple with the stator winding as designed. This improves the air gap magnetic flux and torque density, thereby increasing the motor's output torque and operating efficiency. According to the requirements, the magnetic barrier holes 600 can also guide and organize the magnetic flux, balance the magnetic flux distribution in the rotor core 100, and reduce uneven magnetic flux density. This not only avoids magnetic saturation in some parts of the core due to excessive magnetic flux concentration, but also reduces torque pulsation during motor operation, reduces operating noise and uneven heat generation, and makes the motor run more smoothly.

[0033] Several auxiliary slots 700 are formed on the outer peripheral wall of the rotor core 100. The auxiliary slots 700 can change the magnetic permeability distribution on the rotor surface, making the distribution of the air gap magnetic field smoother, weakening the adsorption effect of the stator slots on the rotor magnetic field, thereby reducing the cogging torque and improving the smoothness of motor operation.

[0034] This embodiment provides a rotor structure that, by designing a first V-shaped slot 400 with its opening facing away from the center point of the rotor core 100 and a second V-shaped slot 500 with its opening facing the center point of the rotor core 100, improves the saliency ratio and reluctance torque compared to the low efficiency and large torque ripple of straight-line magnet slots. This results in reduced motor current and losses at the same torque, improving motor efficiency and reducing load torque ripple. Furthermore, compared to the low utilization and high cost of V-shaped magnet slots, this invention reduces the total number of magnets while maintaining performance, effectively increasing utilization. This makes the overall cost significantly lower than traditional V-shaped magnet slots and close to that of straight-line magnet slots. By employing the first V-shaped slot 400 and the second V-shaped slot 500 with opposite opening designs, combined with the opening of the magnetic barrier hole 600 and the auxiliary slot 700, torque ripple and cogging torque during motor operation can be further reduced, improving the smoothness of motor operation.

[0035] Example 2: This embodiment makes further structural optimizations based on Embodiment 1. Please refer to... Figure 3 Based on the above, refer to Figure 4 and Figure 5 .

[0036] In this embodiment, the outer edge of the rotor core 100 corresponding to the second V-groove 500 includes a first arc segment 110, a first tangent 120 and a second tangent 130 connected in sequence, with the first arc segment 110 close to the D-axis.

[0037] The air gap between the rotor core 100 and the stator core is a critical component of the motor's magnetic circuit. Even slight fluctuations in the air gap size can directly lead to changes in magnetic reluctance, which in turn affects motor efficiency, torque fluctuations, and vibration noise. Therefore, trimming the outer edge of the rotor core 100 can ensure air gap accuracy and bring about improvements in magnetic circuit performance, operational reliability, and reduced losses for the motor.

[0038] There are two auxiliary grooves 700, including a first auxiliary groove 710 and a second auxiliary groove 720; wherein, the first auxiliary groove 710 is formed on the first arc segment 110, and the second auxiliary groove 720 is formed between the first arc segment 110 and the first tangent edge 120.

[0039] In essence, the first arc segment 110 is the maximum outer diameter of the rotor core 100. A first auxiliary groove 710 is formed at the maximum outer diameter of the rotor core 100, and a second auxiliary groove 720 is formed between the maximum outer diameter and the first tangent edge 120. This positional distribution can precisely control the air gap magnetic field distribution, reduce the cogging torque, and take into account the structural stability.

[0040] Specifically, the maximum outer diameter of the rotor core 100 is the area directly coupled with the stator air gap. The first auxiliary slot 710 at this location will directly change the periodic distribution of the air gap magnetic permeability, which can break the periodic effect of the stator slots on the rotor permanent magnet magnetic field, making the waveform of the air gap magnetic field closer to a sine wave, thereby significantly reducing the cogging torque.

[0041] The first tangent 120 and the second tangent 130 are formed on the outer peripheral wall of the rotor core 100. The purpose is to reduce the local air gap and adjust the magnetic flux direction. The second auxiliary slot 720 is formed between the first arc segment 110 and the first tangent 120. This is a secondary fine control of the magnetic circuit in this area. It can guide some magnetic flux to pass through the second auxiliary slot 720 evenly, avoid magnetic flux concentration when the tangent is directly opposite the stator teeth, and further reduce torque pulsation.

[0042] In some embodiments, the minimum distance between the first magnet groove 200 and the second tangent edge 130 is set to H1, the radius of the first auxiliary groove 710 is set to R1, and the radius of the second auxiliary groove 720 is set to R2.

[0043] The minimum distance H1 between the first magnet groove 200 and the second tangent 130, the radius R1 of the first auxiliary groove 710 and the radius R2 of the second auxiliary groove 720 satisfy the following relationship: 0.25 mm < (R1 + R2) / H1 ≤ 1.5 mm; the radius R1 of the first auxiliary groove 710 and the radius R2 of the second auxiliary groove 720 satisfy the following relationship: 0.3 mm ≤ R1 + R2 < 1.8 mm.

[0044] The torque pulsation, noise vibration, and iron loss of a permanent magnet motor are directly related to the sinusoidal nature of the air gap magnetic field. The core function of the first tangent 120, the second tangent 130, the first auxiliary slot 710, and the second auxiliary slot 720 located on the outer peripheral wall of the rotor core 100 is to adjust the air gap permeability, thereby reducing harmonic components in the magnetic field by changing the conduction path of the magnetic field. Specifically, the radius R1 of the first auxiliary slot 710 determines the adjustment range of the permeability at the maximum outer diameter of the rotor core 100, which is used to suppress the fundamental harmonics of the cogging torque; the radius R2 of the second auxiliary slot 720 compensates for the local abrupt change in permeability caused by the first tangent 120, avoiding magnetic field concentration or distortion at the location of the first tangent 120. The minimum distance H1 between the first magnet slot and the second tangent 130 directly affects the diffusion degree of the magnetic flux of the magnet into the region of the second tangent 130. If the minimum distance H1 between the first magnet slot and the second tangent 130 is too large, the regulating effect of the second tangent 130 and the first auxiliary slot 710 and the second auxiliary slot 720 on the magnetic field will be weakened. If the minimum distance H1 between the first magnet slot and the second tangent 130 is too small, it is easy to cause local magnetic saturation between the first magnet slot 200 and the second tangent 130.

[0045] Therefore, the minimum distance H1 between the first magnet slot 200 and the second tangent edge 130, the radius R1 of the first auxiliary slot 710 and the radius R2 of the second auxiliary slot 720 are limited to the range of 0.25 mm < (R1 + R2) / H1 ≤ 1.5 mm; the relationship between the radius R1 of the first auxiliary slot 710 and the radius R2 of the second auxiliary slot 720 is limited to the range of 0.3 mm ≤ R1 + R2 < 1.8 mm. This allows for precise control of the positive orientation of the air gap magnetic field, achieving the goals of reducing torque pulsation, reducing operating noise and optimizing iron loss.

[0046] Furthermore, magnetic saturation of the rotor core 100 can lead to increased motor excitation current and decreased efficiency, and in severe cases, it can affect the motor's overload operation stability. The minimum distance H1 between the first magnet slot and the second tangent edge 130 determines the upper limit of the magnetic flux density in that region. The size of the radius R1 of the first auxiliary slot 710 and the radius R2 of the second auxiliary slot 720 will change the magnetic flux shunting ratio of the surrounding rotor core 100. The larger the radius of the auxiliary slot 700, the stronger its blocking effect on magnetic flux shunting, which can alleviate the concentration of magnetic flux in adjacent regions.

[0047] In some embodiments, the thickness of the first magnet groove 200 in the axial direction is H2, and the thickness of the second magnet groove 300 in the axial direction is H3.

[0048] The thickness H2 of the first magnet groove 200 in the axial direction and the thickness H3 of the second magnet groove 300 in the axial direction satisfy the following relationship: 1.2 * H2 ≥ H3 ≥ H2.

[0049] The adjacent first magnet slot 200 and second magnet slot 300 are arranged in a V-shape. This V-shape optimizes the sinusoidal nature of the air gap magnetic field. If the thickness difference between the first magnet slot 200 and the second magnet slot 300 is too large, it may lead to increased torque pulsation, increased motor operating noise, and increased harmonic losses. Here, by limiting the relationship between the axial thickness H2 of the first magnet slot 200 and the axial thickness H3 of the second magnet slot 300 to the range of 1.2*H2≥H3≥H2, the magnetic reluctance and flux carrying capacity of the magnetic circuits on both sides can be averaged, avoiding local magnetic saturation and ensuring that the motor maintains high efficiency and high stability under both rated and overload conditions.

[0050] In some embodiments, the minimum distance between the first magnet groove 200 and the second tangent edge 130 is set to H1, and the minimum distance between the magnetic barrier hole 600 and the first V-groove 400 is set to H4.

[0051] The minimum distance H1 between the first magnet groove 200 and the second tangent 130 and the minimum distance H4 between the magnetic barrier hole 600 and the first V-groove 400 satisfy the following relationship: 1.1*H1≥H4≥0.8*H1.

[0052] Specifically, the function of the magnetic barrier hole 600 is to block the leakage magnetic path and guide the main magnetic flux to conduct along the air gap direction. Its regulation effect depends on the distance between it and the first V-groove 400. The second tangent 130 adjusts the air gap magnetic permeability by changing the outer diameter shape of the rotor core 100. Its range of action is determined by the distance between it and the first magnet groove 200.

[0053] It is known that the first V-groove 400 includes two second magnet grooves 300. Therefore, the minimum distance between the magnetic barrier hole 600 and the first V-groove 400 is also equivalent to the minimum distance between the magnetic barrier hole 600 and the second magnet groove 300.

[0054] If the minimum distance H4 between the magnetic barrier hole 600 and the first V-groove 400 is too small, the magnetic barrier hole 600 will excessively cut the magnetic circuit of the iron core near the first V-groove 400, resulting in insufficient main magnetic flux conduction area and a decrease in the rated torque of the motor. If the minimum distance H4 between the magnetic barrier hole 600 and the first V-groove 400 is too large, the blocking effect of the magnetic barrier hole 600 on leakage flux will be weakened, the leakage flux of the magnet will increase, and the efficiency of the motor will decrease.

[0055] If the minimum distance H1 between the first magnet slot 200 and the second tangent 130 is too small, the second tangent 130 will directly interfere with the magnetic flux diffusion of the first magnet slot 200, causing local magnetic field distortion; if the minimum distance H1 between the first magnet slot 200 and the second tangent 130 is too large, the adjustment effect of the second tangent 130 on the air gap magnetic permeability cannot cover the magnetic flux influence area of ​​the first magnet slot 200, and the torque pulsation optimization effect will fail.

[0056] Therefore, by limiting the relationship between the minimum distance H1 between the first magnet slot 200 and the second tangent 130 and the minimum distance H4 between the magnetic barrier hole 600 and the first V-groove 400, the leakage magnetic blocking effect of the magnetic barrier hole 600 and the magnetic permeability adjustment effect of the second tangent 130 can complement each other, ensuring efficient conduction of the main magnetic flux and weakening the harmonics of the air gap magnetic field, ultimately achieving the goal of increasing motor output and reducing torque pulsation.

[0057] In some embodiments, the minimum distance between the first magnet groove 200 and the second tangent edge 130 is set to H1, the thickness of the first magnet groove 200 in the axial direction is set to H2, and the thickness of the magnetic bridge between two adjacent magnetic poles in the radial direction is set to H5.

[0058] The minimum distance H1 between the first magnet groove 200 and the second tangent 130, the thickness H2 of the first magnet groove 200 in the axial direction, and the thickness H5 of the magnetic bridge between two adjacent magnetic poles in the radial direction satisfy the following relationship: 0.8 mm ≤ H5 < (H2-H1) / 2 mm.

[0059] Specifically, the magnetic bridges between the first magnet slot 200 and the second tangent edge 130, and between two adjacent magnetic poles, are the core areas with the highest magnetic flux density and are also high-risk areas for magnetic saturation. If the thickness H5 of the magnetic bridge between two adjacent magnetic poles in the radial direction is too small, while the thickness H2 of the first magnet slot 200 in the axial direction is too large, the Q-axis magnetic bridge will saturate first due to the excessively high magnetic flux density, leading to a decrease in Q-axis inductance and a deterioration in the dynamic response characteristics of the motor. If the minimum distance H1 between the first magnet slot 200 and the second tangent edge 130 is too small, even if the thickness H5 of the magnetic bridge between two adjacent magnetic poles is matched in the radial direction, the magnetic flux of the first magnet slot 200 will diffuse excessively into the region of the second tangent edge 130, increasing iron loss and excitation current.

[0060] Therefore, the minimum distance H1 between the first magnet slot 200 and the second tangent 130, the thickness H2 of the first magnet slot 200 in the axial direction, and the thickness H5 of the magnetic bridge between two adjacent magnetic poles in the radial direction are limited to the range of 0.8 mm ≤ H5 < (H2-H1) / 2 mm. This balances the magnetic flux carrying capacity of the critical magnetic circuit and ensures that, under rated and overload conditions, the magnetic flux density between the first magnet slot 200 and the second tangent 130 and the magnetic bridge between two adjacent magnetic poles in the corresponding regions are all lower than the saturation magnetic flux density of the core material, thus ensuring the stability of motor efficiency.

[0061] In some embodiments, the included angle of the first V-groove 400 is θ1, the included angle of the second V-groove 500 is θ2, and the included angle between the first magnet groove 200 and the first tangent edge 120 is θ3.

[0062] The included angle θ1 of the first V-groove 400 satisfies the following relationship: 150°<θ1<170°; the included angle θ1 of the first V-groove 400 and the included angle θ2 of the second V-groove 500 satisfy the following relationship: θ1-θ2<10°; the included angle θ2 of the second V-groove 500 and the included angle θ3 of the first magnet groove 200 and the first tangent 120 satisfy the following relationship: θ2+θ3<180°.

[0063] It is known that the magnetization direction of the magnet in the V-groove is usually perpendicular to the groove wall or along the radial direction of the magnetic pole. The larger the groove angle, the more the magnet is installed in the circumferential direction, the more the circumferential component of the magnetic flux increases and the radial component decreases. Conversely, the smaller the angle, the higher the proportion of the radial component of the magnetic flux, but it is easy to cause the circumferential magnetic flux of adjacent magnets to cancel each other out.

[0064] Specifically, if the difference between the included angle θ1 of the first V-groove 400 and the included angle θ2 of the second V-groove 500 is large, the radial component of the magnetic flux of the magnet in the first V-groove 400 and the magnet in the second V-groove 500 will differ greatly, resulting in an imbalance. The magnet with the weak radial component will not contribute enough effective magnetic flux, leading to a decrease in the total magnetic flux density of the magnetic poles and a reduction in the motor torque output. Therefore, by limiting the relationship between the included angle θ1 of the first V-groove 400 and the included angle θ2 of the second V-groove 500 to the range of θ1-θ2<10°, it can be ensured that the proportion of the radial component of the magnetic flux of the magnets in the first V-groove 400 and the second V-groove 500 is relatively consistent, and the effective magnetic flux is superimposed at the center of the magnetic pole, maximizing the increase of the air gap magnetic flux density, while avoiding mutual cancellation of circumferential components, and suppressing magnetic flux disorder within the poles, thus reducing the risk of local magnetic saturation.

[0065] Specifically, the larger the included angle θ2 of the second V-groove 500, the more the magnetic flux of the magnet is biased towards both sides of the outer diameter of the rotor core 100, and the wider the flat-top section of the air gap magnetic field. Conversely, the smaller the included angle θ2 of the second V-groove 500, the more concentrated the magnetic flux is in the rotor radial direction, and the higher the peak value of the air gap magnetic field. The included angle θ3 between the first magnet groove 200 and the first tangent 120 corresponds to the adjustment range of the first tangent 120 and the air gap magnetic permeability. The function of the first tangent 120 is to eliminate magnetic field harmonics, and its adjustment range needs to match the magnetic flux coverage range corresponding to the included angle θ2 of the second V-groove 500.

[0066] Here, by limiting the included angle θ2 of the second V-groove 500 and the included angle θ3 of the first magnet groove 200 and the first tangent 120 to satisfy the following relationship: θ2+θ3<180°, the magnetic permeability adjustment effect of the first tangent 120 can completely cover the magnetic flux distribution area corresponding to the included angle θ2 of the second V-groove 500. This ensures that the amplitude of the air gap magnetic field meets the torque requirements and also minimizes harmonic components, thereby achieving the goals of increasing motor output, reducing iron loss, and optimizing efficiency.

[0067] In some embodiments, the length of the second magnet slot 300 in the radial direction is L1, and the length of the first magnet slot 200 in the radial direction is L2.

[0068] The length L1 of the second magnet slot 300 in the radial direction and the length L2 of the first magnet slot 200 in the radial direction satisfy the following relationship: 2*L2≥L1≥L2.

[0069] Multiple magnets on the same magnetic pole need to work together to construct a concentrated and uniform unipolar magnetic field. The relationship between the length L1 of the second magnet slot 300 in the radial direction and the length L2 of the first magnet slot 200 in the radial direction directly determines the consistency of the magnetic flux path and the proportion of effective magnetic contribution of each magnet. This is the core means to avoid local magnetic flux saturation and increase the total magnetic flux density of the magnetic pole.

[0070] If the difference between the radial length L1 of the second magnet slot 300 and the radial length L2 of the first magnet slot 200 is too large, it may cause the relative positions of the two magnets to shift in the circumferential direction, making the distance between the two magnets smaller, shortening the leakage magnetic path within the pole, and increasing the leakage magnetic coefficient. Here, limiting the relationship between the two to the range of 2*L2≥L1≥L2 can better utilize the magnetic energy of each magnet, improve the magnetic flux utilization rate, ensure the sinusoidal nature of the air gap magnetic flux waveform, and reduce magnetic wave loss.

[0071] In some embodiments, the length of the first magnet groove 200 in the radial direction is L2, the minimum distance between the first magnet groove 200 and the second tangent 130 is H1, and the angle between the first magnet groove 200 and the first tangent 120 is θ3.

[0072] The length L2 of the first magnet groove 200 in the radial direction, the minimum distance H1 between the first magnet groove 200 and the second tangent 130, and the angle θ3 between the first magnet groove 200 and the first tangent 120 satisfy the following relationship: 0.45*L3*sin(θ3)

[0073] This embodiment provides a rotor structure that, through finite element electromagnetic simulation optimization, reveals that satisfying the above parameter constraints can reduce cogging torque, suppress leakage flux and high-order harmonics while maintaining a high salient pole ratio, and simultaneously ensuring that the motor's power density and efficiency are not affected. Figures 6-9 As shown, Figure 6 A comparison chart showing the back EMF harmonic content, RMS back EMF, cogging torque, phase current, torque, torque pulsation, and total cost (out of 10, with higher scores indicating higher cost) for straight magnet slots, V-shaped magnet slots, and reverse double V-shaped magnet slots. Figure 7 Comparison of no-load back EMF waveforms for straight magnet slots, V-shaped magnet slots, and reverse double V-shaped magnet slots; Figure 8 Comparison of cogging torque waveforms for straight magnet slots, V-shaped magnet slots, and reverse double V-shaped magnet slots; Figure 9 A comparison chart of load torque waveforms for straight magnet slots, V-shaped magnet slots, and reverse double V-shaped magnet slots.

[0074] Depend on Figure 6 As can be seen, compared with the low energy efficiency and large torque ripple of the straight magnet slot, the present invention improves the saliency ratio and reluctance torque by designing a reverse double V-shaped magnet slot structure. Under the same torque, the motor current is reduced. Compared with the straight magnet slot, the phase current is reduced from 34A to 31.4A, which not only reduces losses and improves motor efficiency, but also improves the load torque ripple, reducing the load torque ripple from 15.5% to 12.9%.

[0075] ​Compared with the low magnet utilization and high cost of traditional V-shaped magnet slots, this invention reduces the total number of magnets while ensuring performance, which is equivalent to improving the utilization rate. The overall cost of 10.5 is much lower than the overall cost of 12 of traditional V-shaped magnet slots, and is close to the low cost of straight magnet slots.

[0076] Furthermore, by designing a reverse double V-shaped magnet slot structure, this invention adjusts the magnetic field distribution and improves the motor cogging torque. The cogging torque of the rotor with the reverse double V-shaped magnet slot structure is 1.53, which is lower than the 1.74 of the traditional V-shaped magnet slot structure rotor and much lower than the 2.15 of the straight magnet slot structure rotor, thus having a certain effect on improving motor noise and vibration.

[0077] This invention improves the back EMF harmonic content of the motor by designing a reverse double V-shaped magnet slot structure and combining it with the rotor outer diameter cutting edge. The back EMF harmonic of the rotor with the reverse double V-shaped magnet slot structure is 7.98%, which is lower than the 8.56% of the traditional V-shaped magnet slot rotor and far lower than the 10.39% of the straight magnet slot structure rotor. This has a certain effect on improving motor noise and vibration and increases the stability of electronic control.

[0078] Example 3: This embodiment provides a motor based on embodiment 1 or embodiment 2. Please refer to [link / reference]. Figure 3 .

[0079] An electric motor includes a rotor structure as provided in claim 1 or 2. The rotor structure includes a rotor core 100, which has a plurality of magnetic poles distributed circumferentially. Each magnetic pole is provided with a magnetic slot. The magnetic slots include two first magnetic slots 200 and two second magnetic slots 300 that are connected to each other. The two second magnetic slots 300 are located between the two first magnetic slots 200, and there is one first magnetic slot 200 and one second magnetic slot 300 on each side of the D-axis of the magnetic pole. A first V-shaped slot 400 with an opening facing away from the center point of the rotor core 100 is formed between the two second magnetic slots 300. A second V-shaped slot 500 with an opening facing the center point of the rotor core 100 is formed between adjacent first magnetic slots 200 and second magnetic slots 300. A plurality of magnetic barrier holes 600 are provided between the first V-shaped slot 400 and the outer peripheral wall of the rotor core 100. A plurality of auxiliary slots 700 are formed on the outer peripheral wall of the rotor core 100 corresponding to the second V-shaped slot 500.

[0080] The motor provided in this embodiment, after applying the above-mentioned rotor structure, can better balance the requirements of low cost and high performance.

[0081] The above description is merely an example and illustration of the structure of this invention, and while the description is specific and detailed, it should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these obvious substitutions all fall within the protection scope of this invention.

Claims

1. A rotor structure, characterized in that, Including rotor core (100); The rotor core (100) has multiple magnetic poles distributed circumferentially, and each magnetic pole is provided with a magnetic slot; The magnet slot includes two connected first magnet slots (200) and two second magnet slots (300), with the two second magnet slots (300) located between the two first magnet slots (200), and each of the two sides of the D-axis of the magnetic pole has one first magnet slot (200) and one second magnet slot (300). A first V-shaped groove (400) with an opening opposite to the center point of the rotor core (100) is formed between the two second magnet slots (300), and a second V-shaped groove (500) with an opening facing the center point of the rotor core (100) is formed between adjacent first magnet slots (200) and second magnet slots (300). Among them, a plurality of magnetic barrier holes (600) are provided between the first V-shaped groove (400) and the outer peripheral wall of the rotor core (100), and a plurality of auxiliary grooves (700) are formed on the outer peripheral wall of the rotor core (100) corresponding to the second V-shaped groove (500).

2. The rotor structure according to claim 1, characterized in that, The outer edge of the rotor core (100) corresponding to the second V-groove (500) includes a first arc segment (110), a first tangent (120), and a second tangent (130) connected in sequence, with the first arc segment (110) close to the D-axis; The number of auxiliary slots (700) is two, including a first auxiliary slot (710) and a second auxiliary slot (720); The first auxiliary groove (710) is formed on the first arc segment (110), and the second auxiliary groove (720) is formed between the first arc segment (110) and the first cut edge (120).

3. The rotor structure according to claim 2, characterized in that, wherein... The minimum distance between the first magnet groove (200) and the second tangent (130) is H1, the radius of the first auxiliary groove (710) is R1, and the radius of the second auxiliary groove (720) is R2. H1, R1, and R2 satisfy the following relationship: 0.25mm < (R1 + R2) / H1 ≤ 1.5mm; The R1 and R2 satisfy the following relationship: 0.3 mm ≤ R1 + R2 < 1.8 mm.

4. The rotor structure according to claim 1, characterized in that, wherein... The thickness of the first magnet groove (200) in the axial direction is H2, and the thickness of the second magnet groove (300) in the axial direction is H3; The following relationship exists between H2 and H3: 1.2 * H2 ≥ H3 ≥ H2.

5. The rotor structure according to claim 2, characterized in that, wherein... The minimum distance between the first magnet groove (200) and the second tangent (130) is H1, and the minimum distance between the magnetic barrier hole (600) and the first V-groove (400) is H4. The following relationship exists between H1 and H4: 1.1 * H1 ≥ H4 ≥ 0.8 * H1.

6. The rotor structure according to claim 2, characterized in that, wherein... The minimum distance between the first magnet groove (200) and the second tangent (130) is H1, the thickness of the first magnet groove (200) in the axial direction is H2, and the thickness of the magnetic bridge between two adjacent magnetic poles in the radial direction is H5. The following relationship is satisfied between H1, H2 and H5: 0.8 mm ≤ H5 < (H2-H1) / 2 mm.

7. The rotor structure according to claim 2, characterized in that, wherein... The included angle of the first V-groove (400) is θ1, the included angle of the second V-groove (500) is θ2, and the included angle of the first magnet groove (200) and the first tangent (120) is θ3. The θ1 satisfies the following relationship: 150°<θ1<170°; The θ1 and θ2 satisfy the following relationship: θ1-θ2<10°; The θ2 and θ3 satisfy the following relationship: θ2 + θ3 < 180°.

8. The rotor structure according to claim 1, characterized in that, Let the length of the second magnet slot (300) in the radial direction be L1, and let the length of the first magnet slot (200) in the radial direction be L2; The L1 and L2 satisfy the following relationship: 2*L2≥L1≥L2.

9. The rotor structure according to claim 2, characterized in that, wherein... The length of the first magnet groove (200) in the radial direction is L2. Let the minimum distance between the first magnet groove (200) and the second tangent (130) be H1. Let the angle between the first magnet groove (200) and the first tangent (120) be θ3. The L2, H1, and θ3 satisfy the following relationship: 0.45*L3*sin(θ3) < H1 < 0.65*L3*sin(θ3).

10. An electric motor, characterized in that, The rotor structure includes any one of claims 1-9.

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