Rotor structure

Abstract

The invention provides a rotor structure. The rotor structure comprises a rotor iron core, the rotor core is provided with a plurality of magnetic poles distributed along the circumferential direction, and each magnetic pole is provided with a magnet groove; the magnet grooves comprise two first magnet grooves and two second magnet grooves which are communicated with each other, the two first magnet grooves are located between the two second magnet grooves, and the two sides of the D axis of the magnetic pole are each 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 first 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; by reversely designing the first V-shaped groove and the second V-shaped groove, the magnetic field distribution is adjusted, the cogging torque of the motor is improved, and the performance can be improved while low cost is considered.

Description

Technical Field

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

[0002] As the power core of a variable frequency compressor, the rotor magnet slot structure design of a permanent magnet synchronous motor directly determines the motor's energy efficiency, operational stability, and production cost. (See also...) Figure 1 and Figure 2 The straight magnet slot and the V-shaped magnet slot are two widely used magnet slot structures.

[0003] The advantages of the straight magnet slot are concentrated in cost and production control. From a cost perspective, the straight magnet has a standard rectangular structure, which has high material utilization and simple punching process, effectively reducing the cost of core material loss and making it suitable for mass continuous production. From a production perspective, the straight magnet slot does not require precise calibration of the magnet angle and can be quickly embedded through automated production lines, which has the advantage of fast production cycle. However, due to magnetic circuit design issues, the straight magnet slot is prone to forming a magnetically dense region at the gap between the rotor core and the stator, resulting in uneven magnetic field distribution, which leads to problems such as low motor efficiency and large torque pulsation.

[0004] V-shaped magnet slots, by embedding two permanent magnets into the rotor core at a specific angle in a V-shape, fundamentally improve the magnetic field distribution characteristics and achieve a comprehensive improvement in motor performance. At the same time, by adjusting parameters such as the opening angle of the V-shaped slot, magnet length, spacing, and eccentricity, diverse magnetic circuit topologies can be constructed, enabling precise control of the magnetic field. This significantly improves motor efficiency and effectively suppresses harmonics and torque pulsation. However, the magnet portion near the inner diameter of the V-shaped magnet slot is located in the weak magnetic field region of the magnetic circuit. This part of the material cannot fully participate in magnetic energy conversion. To ensure motor output performance, the design needs to increase the magnet volume to compensate for the insufficient utilization rate, resulting in an increase in the amount of permanent magnets used and driving up motor costs.

[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 that adjusts the magnetic field distribution and improves the motor cogging torque by reversing the design of the first and second V-grooves, thereby improving performance while maintaining low cost.

[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 first magnet slots located between the two second magnet slots, and with one first magnet slot and one second magnet slot existing 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 first 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.

[0008] In some implementations, the distance between the center point of the rotor core and the sharp corner of the first V-groove near the outer periphery of the rotor core is L1, and the maximum outer diameter of the rotor core is R1. L1 and R1 satisfy: 0.7*R1<L1<0.9*R1.

[0009] In some implementations, the side length of the first magnet slot near the inner periphery of the rotor core is L2, and the side length of the second magnet slot near the inner periphery of the rotor core is L3. L2 and L3 satisfy: L3≤L2≤2*L3.

[0010] In some implementations, the included angle of the first V-groove is θ1, and the included angle of the second V-groove is θ2. The relationship between θ1 and θ2 is: θ1-θ2<10°.

[0011] In some implementations, the outer edge of the rotor core corresponding to each of the second V-grooves includes a first arc segment, a first tangent edge, and a second tangent edge connected in sequence. The first arc segment is close to the D-axis.

[0012] In some implementations, the included angle of the second V-groove is θ2, and the included angle between the second magnet groove and the first tangent is θ3. The θ2 and θ3 satisfy the following condition: θ2 + θ3 < 180°.

[0013] In some implementations, the minimum distance between the first magnet slot and the second tangent edge is H1, the side length of the second magnet slot near the inner periphery of the rotor core is L3, and the angle between the second magnet slot and the first tangent edge is θ3. H1, L3 and θ3 satisfy the following condition: 0.45*L3*sin(θ3) < H1 < 0.65*L3*sin(θ3).

[0014] In some implementations, the thickness of the first magnet groove in the radial direction is H2, and the thickness of the second magnet groove in the radial direction is H3. H2 and H3 satisfy: H2≤H3≤1.2*H2.

[0015] In some implementations, the minimum distance between the first magnet slot and the second tangent edge is H1, and the distance between two adjacent second magnet slots located at different magnetic poles is H4. H1 and H4 satisfy: 0.8*H1≤H4≤1.1*H1.

[0016] In some implementations, a magnetic isolation bridge is connected to the end of the second magnet slot away from the first magnet slot.

[0017] In summary, the present invention has at least the following advantages: The present invention provides a rotor structure, which, by designing a first V-shaped slot with an opening away from the center point of the rotor core and a second V-shaped slot with an opening facing the center point of the rotor core, forms a reverse double V-shaped magnet slot structure. Compared with a straight magnet slot, this structure can improve the salient pole and reluctance torque, thereby reducing the motor current to achieve the same torque, thus reducing losses, improving motor efficiency, and improving load torque pulsation. While ensuring performance, the total number of magnets is reduced compared to V-shaped magnet slots, which is equivalent to improving utilization. This makes the overall cost much lower than that of traditional V-shaped magnet slots and close to that of straight magnet slots. The magnetic field distribution was adjusted, and the motor cogging torque was improved. The cogging torque of the reverse double V-shaped magnet slot rotor core is lower than that of the traditional V-shaped magnet slot and much lower than that of the straight magnet slot, which has a significant effect on improving motor noise and vibration. By combining the first tangent edge of the outer diameter, the back EMF harmonic content of the motor is improved. The back EMF harmonic of the reverse double V-shaped magnet slot rotor core is lower than that of the traditional V-shaped magnet slot and much lower than that of the straight magnet slot, which improves noise and increases performance stability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the linear magnet slot mentioned in the background art; Figure 2 This is a schematic diagram of the V-shaped magnet groove 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 7This 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. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more comprehensive description will be given below in conjunction with the accompanying drawings and specific embodiments. The drawings illustrate preferred embodiments of the invention. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Example 1: Please see Figure 3A rotor structure includes a rotor core 100, the rotor core 100 having multiple magnetic poles distributed circumferentially, each magnetic pole having a magnet slot.

[0024] 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.

[0025] The magnet slot includes two connected first magnet slots 200 and two second magnet slots 300. The two first magnet slots 200 are located between the two second magnet slots 300, and there is one first magnet slot 200 and one second magnet slot 300 on each side of the D-axis of the magnetic pole.

[0026] 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 in the middle of the magnet slot, while the two second magnet slots 300 are located at the two ends of the magnet slot. The D-axis is the radial line passing through the center line of the magnetic pole. There is a first magnet slot 200 and a second magnet slot 300 on both sides of the D-axis of the magnetic pole.

[0027] 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 first magnet grooves 200, 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.

[0028] Here, it is equivalent to each magnetic pole having a first V-shaped groove 400 and two second V-shaped grooves 500, with the opening directions of the first V-shaped groove 400 and the second V-shaped groove 500 being opposite. Considering the two first magnetic grooves 200 located on both sides of the D-axis as a single unit, forming a first V-shaped groove 400, and then installing the two magnet segments within the two first magnetic grooves 200 of the first V-shaped groove 400, from an electromagnetic perspective, the principle is consistent with the traditional V-shaped magnetic groove 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.

[0029] 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.

[0030] This embodiment provides a rotor structure that, through the design of 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, forms a reverse double V-shaped magnet slot structure. Compared to a straight magnet slot, this structure can improve salient pole and reluctance torque, thereby reducing motor current to achieve the same torque, thus reducing losses and improving motor efficiency. It also improves load torque ripple. While maintaining performance, compared to V-shaped magnet slots, it reduces the total number of magnets, which is equivalent to improving utilization. The cost of the rotor core is much lower than that of the traditional V-type magnet slot and close to that of the straight magnet slot. The magnetic field distribution is adjusted, which improves the cogging torque of the motor. The cogging torque of the reverse double V-type magnet slot rotor core 100 is lower than that of the traditional V-type magnet slot and much lower than that of the straight magnet slot, which has a significant effect on improving motor noise and vibration. Combined with the first tangent edge 120 of the outer diameter, the back EMF harmonic content of the motor is improved. The back EMF harmonic of the reverse double V-type magnet slot rotor core 100 is lower than that of the traditional V-type magnet slot and much lower than that of the straight magnet slot, which improves noise and increases performance stability.

[0031] Example 2: This embodiment makes further structural optimizations based on Embodiment 1. Please refer to... Figure 3 Based on the above, refer to Figures 4-9 .

[0032] In some embodiments, the distance between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 is L1, and the maximum outer diameter of the rotor core 100 is R1. The distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 and the maximum outer diameter R1 of the rotor core 100 satisfy the following condition: 0.7*R1<L1<0.9*R1.

[0033] The distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 directly determines the installation position of the magnet in the rotor radial direction. The greater the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100, the closer the magnet is to the outer periphery of the rotor core 100, the closer the magnet is to the air gap between it and the stator, the smaller the magnetic resistance of the magnetic field in the air gap, and the higher the magnetic flux density.

[0034] The maximum outer diameter R1 of the rotor core 100 determines the air gap width between the rotor and the stator. If the maximum outer diameter R1 of the rotor core 100 is fixed, and the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 is too large, the effective magnetic circuit length between the magnet and the air gap may be too short, which may easily lead to magnetic flux saturation, that is, the magnetic field strength exceeds the limit of the core material, resulting in increased magnetic loss. If the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 is too small, the magnet will be far away from the air gap, the magnetic resistance will increase, the magnetic field utilization will decrease, and the motor output torque will be significantly reduced.

[0035] Therefore, the relationship between the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100, and the maximum outer diameter R1 of the rotor core 100 is limited to the range of 0.7*R1<L1<0.9*R1, which can better ensure that the magnetic flux density is in the high-efficiency range and directly improve the torque density and efficiency of the motor.

[0036] Furthermore, if the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 is too small, the radial wall thickness of the rotor core 100 will be too thick, easily forming a leakage magnetic channel inside the rotor core. If the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 is too large, the radial wall thickness of the rotor core 100 will be too thin, potentially causing a break in the magnetic circuit between the magnet and the outer periphery of the rotor core 100, with magnetic flux leaking directly from one end of the magnet through the air gap to the other end instead of entering the stator. Therefore, by limiting the relationship between the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-groove 400 near the outer periphery of the rotor core 100 and the maximum outer diameter R1 of the rotor core 100, the magnetic reluctance distribution of the rotor core 100 can be optimized, forcing the magnetic flux to preferentially enter the stator through the air gap, thereby reducing the leakage magnetic coefficient and reducing magnetic loss.

[0037] In some embodiments, the side length of the first magnet slot 200 near the inner periphery of the rotor core 100 is L2, and the side length of the second magnet slot 300 near the inner periphery of the rotor core 100 is L3. The side length L2 of the first magnet slot 200 near the inner periphery of the rotor core 100 and the side length L3 of the second magnet slot 300 near the inner periphery of the rotor core 100 satisfy the following condition: L3≤L2≤2*L3.

[0038] Multiple magnets on the same magnetic pole need to work together to construct a concentrated and uniform unipolar magnetic field. The relationship between the side length L2 of the first magnet slot 200 near the inner periphery of the rotor core 100 and the side length L3 of the second magnet slot 300 near the inner periphery of the rotor core 100 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.

[0039] If the difference between the side length L2 of the first magnet slot 200 near the inner periphery of the rotor core 100 and the side length L3 of the second magnet slot 300 near the inner periphery of the rotor core 100 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 L3≤L2≤2*L3 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.

[0040] In some embodiments, the included angle of the first V-groove 400 is θ1, and the included angle of the second V-groove 500 is θ2. The included angle θ1 of the first V-groove 400 and the included angle θ2 of the second V-groove 500 satisfy the following condition: θ1-θ2<10°.

[0041] 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.

[0042] 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.

[0043] Because the reverse double V-shaped magnet slot design results in the magnet being divided into multiple segments, there is some magnetic leakage between each segment. Compared to the traditional V-shaped magnet slot, this generates additional high-order harmonics, which may have an adverse effect on the motor. Therefore, the relationship between the distance L1 between the center point of the rotor core 100 and the sharp corner of the first V-shaped slot 400 near the outer periphery of the rotor core 100, and the maximum outer diameter R1 of the rotor core 100, is limited to the range of 0.7*R1 < L1 < 0.9*R1; the first magnet... The relationship between the side length L2 of the slot 200 near the inner periphery of the rotor core 100 and the side length L3 of the second magnet slot 300 near the inner periphery of the rotor core 100 is limited to the range of L3≤L2≤2*L3; the relationship between the included angle θ1 of the first V-slot 400 and the included angle θ2 of the second V-slot 500 is limited to θ1-θ2<10°, which can effectively reduce motor harmonics, improve motor electromagnetic performance, and effectively suppress leakage flux and high-order harmonics while ensuring a high saliency ratio.

[0044] In some embodiments, the outer edge of the rotor core 100 corresponding to each second V-groove 500 includes a first arc segment 110, a first tangent 120 and a second tangent 130 connected in sequence; the first arc segment 110 is close to the D-axis.

[0045] 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.

[0046] In some embodiments, the included angle of the second V-groove 500 is θ2, and the included angle of the second magnet groove 300 and the first tangent 120 is θ3. The included angle θ2 of the second V-groove 500 and the included angle θ3 of the second magnet groove 300 and the first tangent 120 satisfy the following condition: θ2 + θ3 < 180°.

[0047] The included angle θ2 of the second V-groove 500 determines the relative position of the magnets, while the included angle θ3 of the second magnet groove 300 and the first tangent 120 affects the air gap shape between the outer periphery of the rotor core 100 and the stator. By limiting the relationship between the included angle θ2 of the second V-groove 500 and the included angle θ3 of the second magnet groove 300 and the first tangent 120 to within θ2+θ3<180°, it can be ensured that the magnetic fields formed by the two magnets can be effectively converged and concentrated in the direction of the air gap, avoiding magnetic field dispersion due to improper angles, and making the magnetic field generated by the magnets act more efficiently on the electromagnetic conversion process of the motor, reducing ineffective magnetic field loss.

[0048] In some embodiments, the minimum distance between the first magnet slot 200 and the second tangent edge 130 is H1, the side length of the second magnet slot 300 near the inner periphery of the rotor core 100 is L3, and the angle between the second magnet slot 300 and the first tangent edge 120 is θ3. The minimum distance H1 between the first magnet slot 200 and the second tangent edge 130, the side length L3 of the second magnet slot 300 near the inner periphery of the rotor core 100, and the angle θ3 between the second magnet slot 300 and the first tangent edge 120 satisfy the following condition: 0.45*L3*sin(θ3) < H1 < 0.65*L3*sin(θ3).

[0049] In some embodiments, the radial thickness of the first magnet groove 200 is H2, and the radial thickness of the second magnet groove 300 is H3. The radial thicknesses H2 of the first magnet groove 200 and H3 of the second magnet groove 300 satisfy: H2≤H3≤1.2*H2.

[0050] The radial thickness of a magnet is directly related to its effective magnetic flux path length. The greater the thickness, the higher the total magnetic flux that can be provided under the same magnet material. Here, the relationship between the radial thickness H2 of the first magnet slot 200 and the radial thickness H3 of the second magnet slot 300 is limited to the range of H2≤H3≤1.2*H2. This can avoid the magnetic fields of the two magnets from being unevenly superimposed at the air gap due to the large difference between the two, resulting in obvious harmonics and thus increasing the cogging torque and torque pulsation. By limiting the reasonable range of the thickness difference between the two, the magnetic field superposition can be smoother, the air gap magnetic flux density waveform can be closer to a sine wave, and the pulsation can be significantly reduced.

[0051] In some embodiments, the minimum distance between the first magnet slot 200 and the second tangent edge 130 is H1, and the distance between two adjacent second magnet slots 300 located at different magnetic poles is H4. The minimum distance H1 between the first magnet slot 200 and the second tangent edge 130 and the distance H4 between two adjacent second magnet slots 300 located at different magnetic poles satisfy: 0.8*H1≤H4≤1.1*H1.

[0052] This embodiment provides a rotor structure that, through finite element electromagnetic simulation optimization, reveals that satisfying the aforementioned parameter constraints can effectively suppress leakage flux and higher harmonics while maintaining a high salient pole ratio. Figures 6-9 As shown, Figure 6 A comparison chart showing the back EMF harmonic content, effective back EMF value V / Krpm, cogging torque Nm, phase current A, torque Nm, torque pulsation, and overall cost (out of 10, with higher scores indicating higher cost) of a single-line magnet slot, a conventional V-type magnet slot, and the reverse double V-type magnet slot of this application. Figure 7 A comparison diagram of the no-load back EMF waveforms of a straight magnet slot, a traditional V-shaped magnet slot, and the reverse double V-shaped magnet slot of this application; Figure 8 A comparison diagram of the cogging torque waveforms of a straight magnet slot, a traditional V-shaped magnet slot, and the reverse double V-shaped magnet slot of this application; Figure 9 A comparison diagram of load torque waveforms for a straight magnet slot, a traditional V-shaped magnet slot, and the reverse double V-shaped magnet slot of this application.

[0053] Example 3: This embodiment further optimizes the structure based on Embodiment 1. Please refer to [link / reference]. Figure 3 .

[0054] In this embodiment, a magnetic isolation bridge is connected to the end of the second magnet slot 300 that is away from the first magnet slot 200.

[0055] The magnetic flux generated by the magnet is prone to lateral dissipation at the end of the magnet slot, such as flowing directly from the end of one magnet to the adjacent magnet or the center of the rotor, forming an ineffective leakage magnetic circuit. Therefore, a magnetic isolation bridge is designed at the end of the second magnet slot 300 away from the first magnet slot 200, so that the leakage magnetic flux at the end of the magnet is difficult to pass through the high magnetic resistance magnetic isolation bridge, and is forced to change its path, turning more towards the air gap to become effective magnetic flux. This can reduce the end leakage magnetic loss, directionally constrain the direction of magnetic flux, and significantly improve the magnetic flux utilization efficiency of the magnet.

[0056] 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 magnet slot; The magnet slot includes two first magnet slots (200) and two second magnet slots (300) that are connected to each other. The two first magnet slots (200) are located between the two second magnet slots (300), and there is one first magnet slot (200) and one second magnet slot (300) on each side of the D-axis of the magnetic pole. A first V-shaped groove (400) with an opening opposite to the center point of the rotor core (100) is formed between the two first magnet slots (200), 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).

2. The rotor structure according to claim 1, characterized in that, Let L1 be the distance between the center point of the rotor core (100) and the sharp corner of the first V-groove (400) near the outer periphery of the rotor core (100), and let R1 be the maximum outer diameter of the rotor core (100). L1 and R1 satisfy: 0.7*R1<L1<0.9*R1.

3. The rotor structure according to claim 1, characterized in that, wherein... The side length of the first magnet slot (200) near the inner periphery of the rotor core (100) is L2, and the side length of the second magnet slot (300) near the inner periphery of the rotor core (100) is L3. L2 and L3 satisfy: L3≤L2≤2*L3.

4. The rotor structure according to claim 1, characterized in that, wherein... The included angle of the first V-groove (400) is θ1, and the included angle of the second V-groove (500) is θ2. The following condition is satisfied between θ1 and θ2: θ1-θ2<10°.

5. The rotor structure according to claim 1, characterized in that, The outer edge of the rotor core (100) corresponding to each of the second V-grooves (500) includes a first arc segment (110), a first tangent (120), and a second tangent (130) connected in sequence. The first arc segment (110) is close to the D axis.

6. The rotor structure according to claim 5, characterized in that, Let the included angle of the second V-groove (500) be θ2, and let the included angle of the second magnet groove (300) and the first tangent (120) be θ3. The following condition must be satisfied between θ2 and θ3: θ2 + θ3 < 180°.

7. The rotor structure according to claim 5, characterized in that, wherein... The minimum distance between the first magnet slot (200) and the second tangent (130) is H1. Let the side length of the second magnet slot (300) near the inner periphery of the rotor core (100) be L3. Let the angle between the second magnet slot (300) and the first tangent (120) be θ3. H1, L3 and θ3 satisfy the following condition: 0.45*L3*sin(θ3) < H1 < 0.65*L3*sin(θ3).

8. The rotor structure according to claim 1, characterized in that, wherein... The thickness of the first magnet groove (200) in the radial direction is H2, and the thickness of the second magnet groove (300) in the radial direction is H3. H2 and H3 satisfy: H2≤H3≤1.2*H2.

9. The rotor structure according to claim 5, characterized in that, wherein... The minimum distance between the first magnet slot (200) and the second tangent (130) is H1. Let the distance between two adjacent second magnet slots (300) located at different magnetic poles be H4. H1 and H4 satisfy: 0.8*H1≤H4≤1.1*H1.

10. The rotor structure according to any one of claims 1-9, characterized in that, A magnetic isolation bridge is connected to the end of the second magnet slot (300) away from the first magnet slot (200).

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