Permanent magnet synchronous motor

Abstract

The utility model discloses a permanent magnet synchronous motor which comprises a rotor, a stator and a rotating shaft, the rotating shaft is arranged at the circle center of the rotor in a penetrating mode, the rotor is embedded in the stator, the middle section of a tooth portion of the stator is arranged in an arc shape, the two ends of the tooth portion of the stator are arranged in a flat cutting mode, and air gaps of the stator and the rotor are arranged in an uneven mode. The permanent magnet synchronous motor comprises a rotor and a stator, the outer circle of the rotor is of a two-section chamfering structure, permanent magnets of a V-shaped structure are arranged in the rotor, and the permanent magnets are distributed at intervals in the circumferential direction of the rotor, according to the permanent magnet synchronous motor, the pole-arc coefficient and the effective air gap length of the motor are adjusted through the outer circle shape of the rotor and the tooth tip shape of the stator, and therefore the motor efficiency is improved. Therefore, the air gap flux density harmonic amplitude is reduced, and the cogging torque and the torque ripple of the motor are reduced.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, and in particular relates to a permanent magnet synchronous motor. Background Technology

[0002] In existing technology, a built-in permanent magnet synchronous motor employs a "V"-shaped rotor structure to improve the motor's saliency ratio. By increasing the effective magnet thickness in the motor's d-axis magnetic circuit, the d-axis inductance is reduced, thereby increasing the motor's saliency ratio and effectively improving its torque capacity. However, while increasing torque capacity, the increased amount of permanent magnets also increases the magnetic field energy in the motor's air gap, leading to increased cogging torque and torque fluctuations. Excessive cogging torque and torque fluctuations during motor operation can cause inconvenience for customers. Therefore, a solution is needed to address these issues.

[0003] It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Utility Model Content

[0004] To address the aforementioned problems, the purpose of this invention is to provide a permanent magnet synchronous motor that adjusts the motor's pole arc coefficient and effective air gap length by adjusting the rotor's outer circle shape and stator tooth tip shape, thereby reducing the air gap magnetic flux density harmonic amplitude, reducing the motor's cogging torque and torque fluctuation. Simultaneously, it adjusts the V-shaped rotor structure's magnetic pole angle and magnetic isolation bridge structure to adjust the d-axis inductance and reduce motor leakage flux, thereby improving the motor's salient pole ratio and torque output capability.

[0005] To achieve the above objectives, this utility model proposes a permanent magnet synchronous motor, including a rotor, a stator, and a rotating shaft. The rotating shaft passes through the center of the rotor, and the rotor is embedded in the stator. The middle section of the teeth of the stator is arc-shaped, and the two ends of the teeth of the stator are flat-cut. The air gaps of the stator and the rotor are unevenly distributed. The outer circle of the rotor has a two-section chamfered structure. V-shaped permanent magnets are disposed inside the rotor, and the permanent magnets are distributed at intervals along the circumference of the rotor.

[0006] In one example, the permanent magnet is composed of an N-pole magnet and an S-pole magnet, which are uniformly arranged along the inner wall of the rotor and are spaced apart.

[0007] In one example, the stator is a concentrated winding configuration, wherein the winding is a single stator tooth winding structure.

[0008] In one example, the inner diameter of the stator is Stator_d (mm), the outer diameter of the rotor is Rotor_d (mm), the effective air gap length Airgap_L (mm) is (Stator_d-Rotor_d) / 2, and the pole arc width Mag_rad (deg) is 360deg / Poles.

[0009] In one example, the magnetization direction length Mag_hc of the permanent magnet is 2.0mm~2.4mm, the width Mag_d of the permanent magnet is 14.0mm~15.0mm, and the included angle of the V-shaped permanent magnet formed by the combination of the N pole magnet and the S pole magnet is 82 degrees~88 degrees.

[0010] In one example, the flattened portion of the stator tooth occupies 0.16 of the total tooth arc and is distributed at both ends of the stator tooth, wherein the flattened portion forms an angle of 86 degrees with the central axis of the stator tooth.

[0011] In one example, the width Bridge_d of the magnetic isolation bridge formed between the two permanent magnets is 1.0mm~1.4mm, and the height Bridge_h is 0.6mm~1.0mm.

[0012] In one example, the rotor is further provided with a number of auxiliary holes, which extend in the axial direction of the rotor and are distributed at intervals along the circumference of the rotor, and the auxiliary holes are located on the side of the permanent magnet away from the rotating shaft.

[0013] In one example, the width of the auxiliary hole, hole_d, is 2.0mm to 2.8mm, the length of the auxiliary hole, hole_L, is 9.6mm to 10.8mm, and the height of the auxiliary hole from the air gap, hole_h, is 0.8mm to 1.2m.

[0014] In one example, the rotor is further provided with weight reduction holes, which extend in the axial direction of the rotor and are distributed at intervals along the circumference of the rotor, and the weight reduction holes are located on the side of the permanent magnet close to the shaft.

[0015] The permanent magnet synchronous motor proposed in this utility model can bring the following beneficial effects:

[0016] 1. By adjusting the rotor outer circle shape and stator tooth tip shape, the motor pole arc coefficient and effective air gap length are adjusted, thereby reducing the air gap magnetic flux density harmonic amplitude and reducing the motor's cogging torque and torque fluctuation.

[0017] 2. By adjusting the magnetic pole angle and magnetic bridge pattern of the V-shaped rotor structure, the d-axis inductance is adjusted and the motor leakage flux is reduced, thereby improving the motor's salient pole ratio and torque output capability.

[0018] 3. By using auxiliary holes in the rotor yoke, the radial force density of the motor can be effectively suppressed. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 This is a cross-sectional view of a permanent magnet synchronous motor according to the present invention.

[0021] Figure 2 This is a schematic diagram of the rotor structure of a permanent magnet synchronous motor according to the present invention.

[0022] Figure 3 This is a schematic diagram of the stator structure of a permanent magnet synchronous motor according to the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of a permanent magnet synchronous motor according to the present invention.

[0024] Figure 5 This is a schematic diagram of the structure of an existing motor;

[0025] Figure 6 A comparison diagram of the motor no-load back EMF waveforms between the existing solution and the new solution of this utility model;

[0026] Figure 7 A comparison diagram of the back electromotive force harmonic amplitude between the existing solution and the new solution of this utility model;

[0027] Figure 8 A comparison diagram of cogging torque between existing solutions and the new solution of this utility model;

[0028] Figure 9 A comparison diagram of motor torque fluctuations between existing solutions and the new solution of this utility model;

[0029] Figure 10 This is a comparison diagram of the radial force of the motor between the existing solution and the new solution of this utility model. Detailed Implementation

[0030] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0031] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 utility model.

[0032] 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "a solution," "some solutions," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that solution or example is included in at least one solution or example of this invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same solution or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more solutions or examples.

[0035] like Figures 1-5 As shown, an embodiment of this utility model proposes a permanent magnet synchronous motor, including a rotor 1, a stator 2 and a rotating shaft 3. The rotating shaft 3 passes through the center of the rotor 1, and the rotor 1 is embedded in the stator 2. The stator 2 and the rotor 1 have a non-uniform air gap design. The middle of the teeth of the stator 2 is arc-shaped, and the two ends are flattened.

[0036] The stator 2 of the permanent magnet synchronous motor has a centralized winding configuration, and the winding is a single stator 2-tooth winding structure;

[0037] The flattened portion of the second stator tooth accounts for 0.16 of the total tooth radius and is distributed at both ends of the second stator tooth. The flattened portion forms an angle of 86 degrees with the central axis of the second stator tooth.

[0038] The rotor 1 is equipped with a V-shaped permanent magnet 4. The permanent magnet 4 is distributed circumferentially along the rotor 1. The permanent magnet 4 is composed of N-pole magnet 41 and S-pole magnet 42. The N-pole magnet 41 and S-pole magnet 42 are evenly arranged inside the rotor 1 and are distributed at intervals. One N-pole magnet 41 and one S-pole magnet form a "V" shaped structure.

[0039] The magnetization direction length Mag_hc of permanent magnet 4 is 2.0mm~2.4mm, the width Mag_d of permanent magnet 4 is 14.0mm~15.0mm, and the included angle of V-shaped permanent magnet 4 is 82 degrees~88 degrees;

[0040] The inner diameter of stator 2 is Stator_d (mm), the outer diameter of rotor 1 is Rotor_d (mm), the effective air gap length Airgap_L (mm) is (Stator_d-Rotor_d) / 2, and the pole arc width of the V-type structure is Mag_rad (deg) 360deg / Poles; where Poles is the number of poles of motor rotor 1.

[0041] The outer circle of rotor 1 adopts a two-section chamfered form. The height of chamfer 1, Cut1_h, is 0.9~1.1 of the effective air gap length Airgap_L, and the height of chamfer 2, Cut2_h, is 0.4~0.6 of the effective air gap length Airgap_L.

[0042] The radius of chamfer 1, Cut1_rad, is 0.08~0.09 of the polar arc length, Mag_rad; the radius of chamfer 2, Cut2_rad, is 0.06~0.07 of the polar arc width, Mag_rad.

[0043] The spacing bridge width Bridge_d between adjacent permanent magnets 4 is 1.0mm~1.4mm, and the magnetic bridge height Bridge_h is 0.6mm~1.0mm, which can satisfy the effect of blocking magnetic leakage and meet the mechanical strength of rotor 1 when rotating;

[0044] The V-shaped permanent magnet 4 has an auxiliary hole 5 in the middle. The width of the auxiliary hole 5, hole_d, is 2.0mm~2.8mm, the length of the auxiliary hole 5, hole_L, is 9.6mm~10.8mm, and the height of the auxiliary hole 5 from the air gap, hole_h, is 0.8mm~1.2mm.

[0045] The rotor 1 is also provided with weight reduction holes 6. The weight reduction holes 6 extend in the axial direction of the rotor 1 and are distributed at intervals along the circumference of the rotor 1. The weight reduction holes 6 are located on the side of the permanent magnet 4 near the rotating shaft 3.

[0046] For an 8-pole, 12-slot motor with a stator outer diameter of 125mm, the motor pole arc coefficient and effective air gap length can be changed by altering the rotor outer circle shape and stator tooth tip shape, thereby reducing the air gap magnetic flux density harmonic amplitude and the motor's cogging torque and torque fluctuation.

[0047] Meanwhile, by changing the pole angle and magnetic bridge pattern of the V-shaped permanent magnet inside the rotor, the d-axis inductance is changed and the motor leakage flux is reduced, thereby improving the motor salient pole ratio and torque output capability.

[0048] In addition, opening auxiliary holes in the rotor yoke can effectively suppress the radial force density of the motor;

[0049] This achieves a 91% reduction in motor cogging torque and a 52.9% reduction in torque ripple.

[0050] Ensuring that the cogging torque generated by the permanent magnet motor under static conditions is small compared to the torque fluctuation under operating conditions improves motor efficiency, extends motor lifespan, increases motor operating stability, reduces noise, and thus enhances the user experience.

[0051] like Figure 6 As shown, the no-load back EMF waveform of the motor is more sinusoidal than that of the existing solution, which improves the ability to drive and control the motor.

[0052] like Figure 7 As shown, compared with the existing scheme, the back EMF harmonic amplitude is reduced and the harmonic proportion is decreased. The THD of the existing scheme is 9.94%, while the THD of the new scheme is 4.48%, and the harmonic proportion is reduced by 54.9%.

[0053] like Figure 8 As shown, compared with the existing solution, the cogging torque is reduced by 91%. The reduction of cogging torque can improve motor efficiency, extend motor life, increase motor operation stability, reduce noise, and thus improve user experience.

[0054] like Figure 9 As shown, compared with the existing solution, the new solution can effectively reduce the torque fluctuation of the motor, thereby improving the smoothness of motor operation. The torque fluctuation of the existing solution is 17.52%, while the torque fluctuation of the new solution is 8.25%, a reduction of 52.9%.

[0055] like Figure 10 As shown, compared with the existing solution, it can effectively reduce the radial force of the motor, thereby reducing the vibration and noise of the motor.

[0056] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0057] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A permanent magnet synchronous motor, characterized by, The application relates to a motor rotor, a stator and a rotating shaft, the rotating shaft is arranged at the center of the rotor, the rotor is embedded in the stator, the middle section of the tooth part of the stator is arranged in a circular arc shape, the two ends of the tooth part of the stator are arranged in a flat cutting mode, the air gaps of the stator and the rotor are unevenly arranged, the outer circle of the rotor is a two-section chamfer structure, the rotor is provided with V-shaped permanent magnets, and the permanent magnets are distributed along the circumferential direction of the rotor.

2. A permanent magnet synchronous motor according to claim 1, characterized in that, The permanent magnets are combined by N-pole magnets and S-pole magnets, the N-pole magnets and the S-pole magnets are uniformly arranged along the inner wall of the rotor, and the N-pole magnets and the S-pole magnets are distributed in a spaced mode.

3. A permanent magnet synchronous motor according to claim 2, characterized in that, The stator is provided with a concentrated winding, wherein the winding is a single-stator-tooth winding structure.

4. A permanent magnet synchronous motor according to claim 1, characterized in that, The inner diameter of the stator is Stator_d, the outer diameter of the rotor is Rotor_d, the expression of the effective air gap length Airgap_L is Airgap_L=(Stator_d-Rotor_d) / 2, the units of Stator_d, Rotor_d and Airgap_L are mm, the pole arc width Mag_rad is 360deg / Poles, the unit of Mag_rad is deg, and Poles represents the pole number of the motor rotor (1).

5. A permanent magnet synchronous motor according to claim 2, characterized in that, The magnetization direction length Mag_hc of the permanent magnet is 2.0mm-2.4mm, the width Mag_d of the permanent magnet is 14.0mm-15.0mm, the included angle of the V-shaped permanent magnet combined by the N-pole magnet and the S-pole magnet is 82 degrees-88 degrees.

6. A permanent magnet synchronous motor according to claim 1, characterized in that, The flat cutting part of the tooth part of the stator accounts for 0.16 of the entire tooth arc, and is distributed at the two ends of the tooth part of the stator, wherein the included angle between the flat cutting part and the center axis of the stator tooth is 86 degrees.

7. A permanent magnet synchronous motor according to claim 1, characterized in that, The width Bridge_d of the magnetic isolation bridge formed between adjacent permanent magnets is 1.0mm-1.4mm, and the height Bridge_h of the magnetic isolation bridge is 0.6mm-1.0mm.

8. A permanent magnet synchronous motor according to claim 1, characterized in that, The rotor is further provided with a plurality of auxiliary holes, the auxiliary holes extend in the axial direction of the rotor and are distributed along the circumferential direction of the rotor, and the auxiliary holes are located on the side of the permanent magnet away from the rotating shaft.

9. A permanent magnet synchronous motor according to claim 8, characterized in that, The width hole_d of the auxiliary hole is 2.0mm-2.8mm, the length hole_L of the auxiliary hole is 9.6mm-10.8mm, and the height hole_h of the auxiliary hole from the air gap is 0.8mm-1.2mm.

10. A permanent magnet synchronous motor according to claim 1, characterized in that, The rotor is further provided with a weight-reducing hole, the weight-reducing hole extends in the axial direction of the rotor and is distributed along the circumferential direction of the rotor, and the weight-reducing hole is located on the side of the permanent magnet close to the rotating shaft.

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