Stator and rotor structure of permanent magnet synchronous motor

Abstract

The utility model provides a stator and rotor structure of a permanent magnet synchronous motor, and the structure comprises a rotor yoke which is of an annular structure; the permanent magnets are uniformly and annularly distributed on the inner wall of the rotor yoke; the stator iron core is of an annular structure and is located in the rotor yoke; stator teeth protruding outwards are annularly distributed on the outer wall of the stator core, and two auxiliary grooves are formed in the tail end of each stator tooth. And the stator windings are arranged between the adjacent stator teeth. According to the invention, the rectangular auxiliary grooves are added, and the permanent magnets are designed into cambered surface structures, so that the operation stability is effectively improved.

Description

Technical Field

[0001] This application relates to the field of permanent magnet synchronous motors, and more specifically, to a stator and rotor structure for a permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet motors are widely used in industrial drives and new energy vehicles due to their high power density and high efficiency. However, several key issues in the design of traditional permanent magnet motors still need to be addressed. Regarding stator structure design, existing technologies generally employ a single physical slot structure. Limited by the relationship between the number of stator slots and the number of rotor poles, the least common multiple is difficult to effectively increase. This deficiency results in a long cogging torque period and a large amplitude, causing significant torque pulsation during motor operation, leading to vibration and noise, and affecting system control accuracy. Although some improvement schemes attempt to mitigate this problem by increasing the actual number of stator slots, limitations in cogging space utilization and manufacturing processes often result in material waste or magnetic circuit saturation.

[0003] On the other hand, existing permanent magnet structural designs suffer from significant technical bottlenecks. Conventional permanent magnets often employ flat-top or asymmetrical curved surface structures, which easily lead to distortion of the air gap magnetic field distribution and the generation of high-order harmonic components. Particularly in the bonding process between the permanent magnet and the stator core surface, traditional designs lack effective modulation of the magnetic field waveform, resulting in poor sinusoidal air gap magnetic field characteristics. The resulting torque fluctuations severely restrict the motor's performance in high-precision control applications. Furthermore, asymmetrical magnetic pole structures can cause radial magnetic pull imbalance, further exacerbating mechanical vibration and affecting the service life of the bearing system. These inherent defects have become major technical obstacles hindering the development of permanent magnet motors towards higher stability and lower noise. Utility Model Content

[0004] In view of one of the defects in the prior art, the purpose of this application is to provide a stator and rotor structure for a permanent magnet synchronous motor.

[0005] A first aspect of this application provides a stator and rotor structure for a permanent magnet synchronous motor, comprising:

[0006] The rotor yoke has a ring-shaped structure.

[0007] Permanent magnets are evenly distributed around the inner wall of the rotor yoke;

[0008] The stator core has a ring structure and is located inside the rotor yoke and is concentric with it; the outer side wall of the stator core is evenly distributed with outwardly protruding stator teeth, and the end of each stator tooth is provided with at least one auxiliary groove; a stator slot is formed between adjacent stator teeth;

[0009] The stator windings are fixed in the stator slots one by one, corresponding to the stator slots.

[0010] Optionally, one side of the permanent magnet is in contact with the inner wall of the rotor yoke.

[0011] Optionally, the permanent magnet includes an upper arc surface and a lower arc surface, the upper arc surface and the lower arc surface being symmetrical about the center line of the permanent magnet.

[0012] Optionally, the air gap magnetic field waveform between the stator core and the permanent magnet has sinusoidal characteristics.

[0013] Optionally, the number of permanent magnets is 20, the radius of the upper arc surface and the lower arc surface is 40mm, the inner diameter of the rotor yoke is 80mm, and the outer diameter is 82mm.

[0014] Optionally, the ratio of the number of stator teeth to the number of permanent magnets is 9:10.

[0015] Optionally, the stator teeth gradually extend outward from the stator core, with their ends expanding to both sides to form a T-shaped structure.

[0016] Optionally, each stator tooth has two auxiliary slots, and the two auxiliary slots are symmetrically distributed with respect to the center line of the stator tooth.

[0017] Optionally, the auxiliary groove is a rectangular structure with a width of 0.5m and a depth of 1mm.

[0018] Optionally, the stator winding is a fractional-slot concentrated winding.

[0019] The stator and rotor structure of the permanent magnet synchronous motor provided in this application adopts the technical means of adding auxiliary slots, which brings about the technical effect of improving the smoothness of motor operation.

[0020] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0021] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the stator and rotor structure of a permanent magnet synchronous motor according to an exemplary embodiment;

[0023] Figure 2 This is a schematic diagram of stator teeth according to an exemplary embodiment;

[0024] Figure 3 This is a schematic diagram of a permanent magnet according to an exemplary embodiment.

[0025] In the diagram: 1-rotor yoke, 2-stator winding, 3-stator core, 4-air gap, 5-auxiliary slot, 6-stator tooth, 7-permanent magnet. Detailed Implementation

[0026] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0027] Terminology Explanation:

[0028] Rotor: The integral structure consisting of the rotor yoke and permanent magnets;

[0029] Stator slot: The groove between adjacent stator teeth used to install windings.

[0030] Number of stator slots: The number of stator slots.

[0031] Number of poles: The permanent magnets have alternating N, N poles. The number of poles refers to the number of permanent magnets.

[0032] Cogging torque: Due to the presence of stator slots, the rotor tends to remain in certain specific positions when stationary. The magnitude of this force varies periodically with the relative positions of the stator and rotor, with an average value of 0, and does no external work.

[0033] Period: The period of cogging torque.

[0034] Amplitude: The magnitude of the cogging torque.

[0035] Virtual slots: These are auxiliary slots carved into the stator teeth, which are not used to install windings.

[0036] The operational smoothness of existing motors needs further improvement. Based on this need, this application provides a stator and rotor structure for a permanent magnet synchronous motor to meet the requirement of improving motor operational smoothness.

[0037] Reference Figure 1 As shown, a stator-rotor structure of a permanent magnet synchronous motor includes a rotor yoke 1, permanent magnets 7, and a stator core 3. The rotor yoke 1 has a ring-shaped structure. The permanent magnets 7 are evenly distributed around the inner wall of the rotor yoke 1.

[0038] The stator core 3 has a ring structure and is located inside the rotor yoke 1 and is concentric with it. The outer side wall of the stator core 3 is evenly distributed with outwardly protruding stator teeth 6, and the end of the stator teeth 6 is provided with at least one auxiliary slot 5. A stator slot is formed between adjacent stator teeth 6. The stator winding 2 is fixed in the stator slot in a one-to-one correspondence with the stator slot.

[0039] Specifically, under normal circumstances, when a permanent magnet 7 passes through one stator slot, the cogging torque fluctuates once. For every revolution of the permanent magnet motor rotor, the cogging torque fluctuates a total of NL times. N represents the number of stator slots, L represents the number of poles, and NL is the least common multiple of the number of poles and slots.

[0040] The cycle of one cogging torque fluctuation is 360 divided by NL. Generally, for motors of the same specifications, the larger NL is, the smaller the amplitude. Due to the existence of cogging torque, the motor rotor tends to stay in a fixed position, which affects the control accuracy of the motor. Secondly, cogging torque is a periodic torque fluctuation, which will cause additional torque fluctuations, and these fluctuations will generate noise, thus affecting the noise of the motor.

[0041] In the above embodiments of this application, auxiliary slots are provided to increase the number of virtual slots, effectively increasing the least common multiple of the number of slots (the number of slots here refers to the sum of virtual slots and stator slots) and the number of poles, effectively reducing the period of cogging torque, reducing the amplitude of cogging torque, and increasing the smoothness of motor operation.

[0042] In order to further improve the smoothness of motor operation, in some specific embodiments of this application, one surface of the permanent magnet 7 is in contact with the inner wall of the rotor yoke 1.

[0043] Specifically, such as Figure 3 As shown, the permanent magnet includes an upper arc surface and a lower arc surface with the same radius, and the upper and lower arc surfaces are symmetrical about the center line of the permanent magnet.

[0044] For example: the permanent magnets are uniformly distributed in the circumferential direction, the number of permanent magnets is 20, the radius of the upper and lower arc surfaces is 40mm, the inner diameter of the rotor yoke is 80mm, and the outer diameter is 82mm. The ratio of stator teeth to permanent magnets is 9:10, and there are 18 stator teeth.

[0045] The embodiments described above in this application, through a symmetrical arc surface design, ensure uniform air gap length, suppress edge effects, and optimize magnetic flux distribution, effectively reducing air gap magnetic field harmonics and enhancing the sinusoidal nature of the magnetic field. With a permanent magnet radius of 40mm and a rotor yoke inner diameter of 80mm, a "perfect fit" is achieved, resulting in a smoother magnetic field waveform and reduced high-order harmonic amplitude. This directly suppresses torque ripple and improves the smoothness and efficiency of motor operation.

[0046] In order to better fix the stator winding, in some specific embodiments of this application, the stator teeth 6 gradually extend outward from the stator core 3, and the ends expand and extend to both sides to form a T-shaped structure.

[0047] Specifically, the stator winding of this application is a fractional-slot concentrated winding, installed between adjacent stator teeth. Compared with an integer-slot distributed winding, the winding ends are shorter, the back EMF harmonics are smaller, and the cogging torque is smaller.

[0048] To further improve the smoothness of motor operation, some specific embodiments of this application, such as... Figure 2 The two auxiliary slots on each stator tooth are symmetrical about the center line of that stator tooth.

[0049] For example, the auxiliary groove is a rectangular structure with a width of 0.5m and a depth of 1mm.

[0050] In the embodiments described above, the auxiliary slot is located on the upper part of the stator teeth, close to the air gap. The rectangular auxiliary slot serves to increase the number of virtual slots, effectively increasing the least common multiple of the number of slots (here, the number of slots refers to the sum of virtual slots and stator slots) and the number of poles, effectively reducing the period of the cogging torque, reducing the amplitude of the cogging torque, and increasing the smoothness of motor operation.

[0051] The preferred features in the above embodiments can be used individually in any embodiment, or in any combination thereof, provided they do not conflict with each other. Furthermore, parts not described in detail in the embodiments can be implemented using existing technologies.

[0052] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0054] In the description of the embodiments in this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or devices.

Claims

1. A stator and rotor structure for a permanent magnet synchronous motor, characterized in that, include: The rotor yoke has a ring-shaped structure. Permanent magnets are evenly distributed around the inner wall of the rotor yoke; The stator core has a ring-shaped structure and is located inside the rotor yoke and is concentric with it; the outer side wall of the stator core is evenly distributed with outwardly protruding stator teeth, and the end of each stator tooth is provided with at least one auxiliary slot; the space between adjacent stator teeth forms a stator slot; The stator windings are fixed in the stator slots one by one, corresponding to the stator slots.

2. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, One side of the permanent magnet is in contact with the inner wall of the rotor yoke.

3. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, The permanent magnet includes an upper arc surface and a lower arc surface, which are symmetrical about the center line of the permanent magnet.

4. The stator and rotor structure of a permanent magnet synchronous motor according to claim 3, characterized in that, The air gap magnetic field waveform between the stator core and the permanent magnet has sinusoidal characteristics.

5. The stator and rotor structure of a permanent magnet synchronous motor according to claim 3, characterized in that, The number of permanent magnets is 20, the radius of the upper arc surface and the lower arc surface is 40mm, the inner diameter of the rotor yoke is 80mm, and the outer diameter is 82mm.

6. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, The ratio of the number of stator teeth to the number of permanent magnets is 9:

10.

7. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, The stator teeth gradually extend outward from the stator core, with their ends expanding to both sides to form a T-shaped structure.

8. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, Each stator tooth has two auxiliary slots, and the two auxiliary slots are symmetrically distributed with respect to the center line of the stator tooth.

9. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, The auxiliary groove is a rectangular structure with a width of 0.5m and a depth of 1mm.

10. The stator and rotor structure of a permanent magnet synchronous motor according to claim 1, characterized in that, The stator winding is a fractional slot concentrated winding.

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