Brushless direct current slot motor stator structure, preparation method and motor

Abstract

The application discloses a brushless direct-current slot motor stator structure, a preparation method and a motor. The preparation method comprises the following steps in sequence: dividing the stator slots into main slots and auxiliary slots, the auxiliary slots being symmetrically distributed on the two sides of the main slots, the stator slots being uniformly distributed in the circumferential direction of the motor stator, defining the teeth between adjacent stator slots as main teeth, the teeth between adjacent main slots and auxiliary slots as winding teeth, the tooth width proportion of the winding teeth in the circumferential direction being a constant 1.51%, the ratio of the width proportions of the main slots and the auxiliary slots in the circumferential direction being 1.2-3.0, and the sum of the proportions of the stator slots and the winding teeth in the circumferential direction being less than 80.46%; performing tooth cutting treatment on the auxiliary slots, selecting a tooth cutting area with a central angle range less than 6° on the side of the auxiliary slots close to the main teeth, the outer ring of the tooth cutting area and the bottom of the auxiliary slot extending in the same direction, performing performance verification in the 6° central angle range at a predetermined step length, selecting a target tooth cutting area, and obtaining the motor stator structure capable of effectively inhibiting torque fluctuation after removing the target tooth cutting area.

Description

Technical Field

[0001] This invention relates to the field of electric motor technology, and in particular to the stator structure, manufacturing method, and electric motor of a brushless DC pole slot motor. Background Technology

[0002] Brushless direct current motors (BLDCs), by replacing mechanical brushes with electronic commutation, offer advantages such as high efficiency, high power density, and low maintenance costs, and have been widely used in industrial automation, aerospace, and home appliances. However, because BLDC motors are typically driven by square wave current, their stator magnetic field is discontinuously distributed, resulting in torque ripple higher than that of motors driven by sinusoidal waves. Studies have shown that torque ripple not only affects the smoothness of motor operation but also induces vibration and noise, which is particularly prominent in high-precision servo control scenarios. Furthermore, due to the presence of phase inductance during winding commutation, current changes lag behind the ideal commutation time, causing significant drops or spikes in electromagnetic torque during commutation, further exacerbating torque ripple.

[0003] On the other hand, traditional brushless DC motors typically have uniformly distributed stator slots, resulting in a simple structural design. In applications with limited installation space or high adaptability requirements (such as micro-actuators, robot joints, and medical devices), existing structures struggle to meet the demands for compact and customized assembly. Furthermore, conventional stator structures suffer from issues such as high magnetic leakage and low slot fill factor. Excessive magnetic leakage reduces the utilization rate of permanent magnets, leading to increased phase current and decreased efficiency; low slot fill factor limits further increases in power density.

[0004] Therefore, existing brushless DC motors suffer from problems such as low motor operation stability, large torque fluctuations, large leakage flux, and low slot fill factor, which further lead to high motor energy consumption and high operating costs. Thus, there is an urgent need for a stator structure optimization design scheme that can suppress torque fluctuations while improving space utilization, as well as an energy-saving motor, to balance the motor's electromagnetic performance, structural adaptability, and manufacturing and operating costs. Summary of the Invention

[0005] This application provides a stator structure, manufacturing method, and motor for a brushless DC pole slot motor. It is suitable for pole slot motors with adjacent stator slot positions occupied by each phase winding. It can effectively suppress torque fluctuations, improve slot fill factor, enhance structural adaptability, save energy, and reduce operating costs.

[0006] The first aspect of this application provides a method for fabricating a stator structure of a brushless DC pole slot motor, comprising the following steps: S10, the stator slots on the motor stator are divided into main slots and auxiliary slots, wherein the auxiliary slots are symmetrically distributed on both sides of the main slots. The stator slots are in several groups and are evenly distributed in the circumferential direction of the motor stator. The teeth between several groups of adjacent stator slots are defined as main teeth, and the teeth between adjacent main slots and auxiliary slots are defined as winding teeth for winding the motor winding coil. The stator slots, together with the internal winding coils, constitute one phase of the motor. The proportion of the circumferential tooth width of the winding teeth is a fixed value of 1.51%. The ratio of the circumferential width of the main slots and the auxiliary slots is 1.2-3.0, and the sum of the circumferential proportions of the stator slots and the winding teeth is less than 80.46%. S20, the secondary slot is subjected to tooth trimming. A tooth trimming area is selected on the side of the secondary slot near the main tooth, wherein the central angle range of the tooth trimming area in the circumferential direction is less than 6°. The outer circle of the tooth trimming area extends in the same direction as the bottom of the secondary slot. Parametric motor performance verification is performed within a 6° central angle range with a predetermined step size. The target tooth trimming area is selected. After removing the target tooth trimming area, the motor stator structure is obtained. The motor performance includes motor torque fluctuation, motor current RMS value, and motor stator iron loss.

[0007] In one possible implementation, the stator slots and the main teeth are each in three sets, and the stator slots and the main teeth are distributed sequentially at intervals.

[0008] In one possible implementation, the ratio of the width of the main groove to that of the secondary groove in the circumferential direction is 1.6, and the predetermined step size is 2°.

[0009] In one possible implementation, the central angle α of the target tooth-cutting region at the inner circle of the secondary groove is 6°, and the central angle β of the target tooth-cutting region at the outer circle of the secondary groove is 3°.

[0010] In one possible implementation, the ratio of the width of the main groove to that of the secondary groove in the circumferential direction is 2.8, and the predetermined step size is 1.5°.

[0011] In one possible implementation, the central angle α of the target tooth-cutting region at the inner circle of the secondary groove is 4.5°, and the central angle β of the target tooth-cutting region at the outer circle of the secondary groove is 0°.

[0012] In one possible implementation, the method for preparing the stator structure of the brushless DC pole slot motor further includes step S30, defining the three main teeth as a first main tooth, a second main tooth, and a third main tooth in the circumferential direction, respectively, and opening a mounting hole on the first main tooth and the second main tooth, wherein the radius of the mounting hole is 1.1-1.2 mm, and opening a grounding hole on the third main tooth, wherein the length of the grounding hole is 1.15-1.25 mm and the width is 0.62-0.66 mm.

[0013] The second aspect of this application provides a brushless DC pole slot motor stator structure, including a motor stator body. The motor stator body has a plurality of sets of stator slots and a plurality of main teeth. The stator slots and the main teeth are distributed sequentially at intervals in the circumferential direction. The stator slots include main slots and auxiliary slots. The auxiliary slots are symmetrically distributed on both sides of the main slots in the circumferential direction. A winding tooth is provided between the main slots and the auxiliary slots in the same set of stator slots. The tooth width of the winding tooth occupies a fixed proportion of 1.51% in the circumferential direction. The ratio of the width of the main slots and the auxiliary slots in the circumferential direction is 1.2-3.2. The sum of the proportions of the stator slots and the winding teeth in the circumferential direction is less than 86.64%. The motor winding coil is wound on adjacent main slots and auxiliary slots. The stator slots, together with the internal winding coils, constitute one phase of the motor.

[0014] In one possible implementation, the stator slots have three sets, and the main teeth have three, defined as a first main tooth, a second main tooth, and a third main tooth in the circumferential direction. A mounting hole is formed on the first main tooth and the second main tooth, wherein the radius of the mounting hole is 1.1-1.2 mm, and a grounding hole is formed on the third main tooth, wherein the length of the grounding hole is 1.15-1.25 mm and the width is 0.62-0.66 mm.

[0015] A third aspect of this application provides a brushless DC pole slot motor, including a rotor and a brushless DC pole slot motor stator structure as described above, wherein the motor stator body has a rotor cavity at the central axis, the rotor is located at the center of the rotor cavity, and cooperates with the motor stator body.

[0016] Beneficial effects: Compared with the prior art, the brushless DC pole slot motor stator structure, manufacturing method and motor provided in this application divide the conventional motor stator slots into main slots and auxiliary slots with a predetermined combination arrangement. This can achieve unequal slot width distribution of the motor stator slots while keeping the total number of motor slots unchanged, change the stator air gap magnetic permeability distribution, reduce motor leakage flux, thereby effectively reducing the phase current of the motor, and widening the back EMF flat top width of the motor to reduce torque fluctuation; The motor windings have been improved from the conventional two sets of windings per stator slot to two sets of windings only in the main slot and only one set of windings in the auxiliary slot. This makes each phase winding consist of the main slot coil and the auxiliary slot coil connected in series, which simplifies the winding structure, reduces the complexity of winding manufacturing, and frees up internal space in the stator, improving the flexibility of motor structure design and assembly adaptability. By setting a tooth-cutting structure between two adjacent phases and parametrically designing the tooth-cutting angle parameter, the back EMF flat top width of the motor can be further widened, the torque fluctuation of the motor can be reduced, and energy consumption can be reduced, which can effectively reduce the cost of use. By designing mounting holes and grounding holes in the main gear, the installation requirements between the motor and the gear can be met, and the grounding spring on the control board can be eliminated, which can further reduce the cost of the motor.

[0017] These and other objects, features and advantages of the present invention will become fully apparent from the following detailed description. Attached Figure Description

[0018] Figure 1 A schematic diagram of the conventional BLDC topology in the prior art is shown.

[0019] Figure 2 A schematic flowchart of the method for fabricating the stator structure of the brushless DC pole slot motor of this application is shown.

[0020] Figure 3 A schematic diagram of the stator structure of the brushless DC pole slot motor of this application is shown.

[0021] Figure 4 A schematic diagram of the selection of the target tooth-cutting area in Embodiment 1 of this application is shown.

[0022] Figure 5 A schematic diagram of the selection of the target tooth-cutting area in Embodiment 2 of this application is shown. Detailed Implementation

[0023] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0024] Those skilled in the art should understand that, in the disclosure of this specification, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present 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. Therefore, the above terms should not be construed as limiting the present invention.

[0025] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will also be understood that terms, such as those defined in commonly used dictionaries, shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0026] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0027] refer to Figure 2 The first aspect of this application provides a method for fabricating a stator structure of a brushless DC pole slot motor, comprising the following steps: S10, the stator slots on the motor stator are divided into main slots and auxiliary slots. The motor stator is circular, and there are several groups of stator slots, evenly distributed along the circumference of the motor stator. The auxiliary slots are symmetrically distributed on both sides of the main slots along the circumference. The teeth between several groups of adjacent stator slots are defined as main teeth, and the teeth between the main and auxiliary slots within the same group of stator slots are defined as winding teeth, or in other words, the teeth between adjacent main and auxiliary slots are winding teeth. The winding teeth are used to wind the motor winding coils. The stator slots, together with the internal winding coils, constitute one phase of the motor. The circumferential width of the winding teeth occupies a fixed proportion of 1.51%. The ratio of the circumferential width of the main slots to the auxiliary slots is 1.2-3.0. The sum of the proportions of the stator slots and the winding teeth in the circumferential direction is less than 80.46%. That is, assuming the total circumference of the motor stator is 100, the tooth width of each winding tooth in the circumferential direction is 1.51. At the same time, the sum of the widths of all stator slots in the circumferential direction is less than 80.46 - 1.51 * the number of winding teeth. Here, any width in the circumferential direction can be calibrated by the central angle. The proportion of the circumferential tooth width of the winding teeth is a fixed value of 1.51%, which allows for more slot space and prevents magnetic saturation in the motor. Furthermore, the sum of the circumferential slot widths of the main slot and the auxiliary slots must be less than 25.86%. This ensures that the sum of the main slot width + the widths of two auxiliary slots + the width of two winding teeth in one stator slot is less than 25.86 + 2 * 1.51 = 28.88%, resulting in a slot fill factor below 60%. This significantly reduces the slot fill factor and improves the motor's heat dissipation. Additionally, considering the subsequent tooth trimming process, sufficient space must be reserved. After extensive experimental verification and reverse calculations, it was finally determined that the sum of the circumferential proportions of all stator slots and all winding teeth is less than 80.46%. Taking a 9-slot 8-pole BLDC motor as an example, the motor has three phases. 80.46% is less than 3*28.88%=86.64%, and the margin of 86.64%-80.46%=6.18% can be used as the maximum tooth cutting area. S20, the auxiliary slot is subjected to tooth trimming (also known as beveling or edge trimming). A tooth trimming area is selected on the side of the auxiliary slot near the main tooth, wherein the central angle range of the tooth trimming area in the circumferential direction is less than 6°. The outer circle of the tooth trimming area extends in the same direction as the bottom of the auxiliary slot. That is, a central angle α is taken on the inner circle of the stator slot with the center of the motor stator as the center, and a central angle β is taken on the outer circle of the stator slot with the center of the motor stator as the center. At the same time, the central angle β extends in the same direction as the bottom of the auxiliary slot. Finally, the boundaries of the central angles α and β are smoothly connected by an arc curve to form a fan-shaped tooth trimming area. A central angle range of less than 6° means that both the central angles α and β are less than 6°. Parametric motor performance verification is performed within a 6° central angle range with a predetermined step size. The target tooth trimming area is selected. After removing the target tooth trimming area, the motor stator structure is obtained, wherein the motor performance includes motor torque fluctuation, motor current RMS value, and motor stator iron loss.

[0028] Taking a 9-slot 8-pole BLDC motor as an example, the stator slots and main teeth each have three sets, and the stator slots and main teeth are distributed sequentially at intervals. The motor parameters are shown in Table 1.

[0029] Table 1 Specific parameters of BLDC

[0030] The conventional topology of BLDC for automotive actuators is as follows: Figure 1 As shown, Figure 1 The stator core of the motor has nine stator slots evenly distributed along the circumference. The rotor adopts an 8-pole permanent magnet structure, with the permanent magnets attached to the surface of the rotor core. The motor uses a three-phase star-connected winding, with each phase winding embedded in its corresponding stator slot.

[0031] This invention is conventional as... Figure 1 Based on the topology shown, while keeping the total number of stator slots constant, a stator topology with alternating main and auxiliary slots is formed by reducing the area of ​​the auxiliary slots on both sides of the main slot. The main slots are located in the middle of each phase and have a larger slot width; the auxiliary slots are located on both sides of the main slots and have smaller slot widths. The main slot and its two adjacent auxiliary slots, along with their internal coils, constitute one phase of the motor. Based on the unequal width design of the stator slots, the number of winding conductors in each slot is reconfigured: the number of conductors arranged in the main slot is significantly greater than that in the auxiliary slots, forming a non-uniform distribution structure with dense conductors in the main slots and sparse conductors in the auxiliary slots. In this embodiment, the number of conductors in the main slot is 210, and the number of conductors in the auxiliary slot is 105, with the number of conductors in the main slot being twice that of the auxiliary slot.

[0032] Within the range of 1.2-3.0, the ratio of the width of the main slot to the auxiliary slot in the circumferential direction is successively selected to form the following Table 2: Motor Main Slot / Auxiliary Slot Ratio and Motor Performance Information: Table 2. Main slot / secondary slot ratio and motor performance information

[0033] In the table above, W A W refers to the proportion of the main groove's width in the circumferential direction. C W refers to the proportion of the width of the secondary groove in the circumferential direction. A / W C This refers to the ratio of the width of the main slot to the width of the auxiliary slot in the circumferential direction. As can be seen from the table above, after the improvement, the motor current is reduced to a certain extent, torque fluctuation and iron loss are significantly reduced, and the external voltage is also reduced to a certain extent.

[0034] The improved models of motors 3 and 6 have a larger space for tooth cutting, and the trend of motor performance changes can be clearly seen. Therefore, motors 3 and 6 in Table 2 are selected for further detailed study to improve the universality of the tooth cutting method and prove its effectiveness.

[0035] Example 1: Taking a ratio of 1.6 between the width of the main slot and the secondary slot in the circumferential direction as an example. Assuming the main slot width is 34.5°, accounting for 9.58%, then the secondary slot width is 24.7°, accounting for 6.86%. In this case, the main slot width + the widths of two secondary slots + the widths of two winding teeth = 9.58% + 2 * 6.86% + 2 * 1.51% = 26.32%, which is less than 28.88%. Selecting a predetermined step size of 2°, and optimizing the design within the 0°-60° range of the stator tooth cutting central angle, the improved motor 3 tooth cutting scanning results are shown in Table 3 below: Table 3. Improved motor 3 tooth cutting scanning results

[0036] Table 3 shows that when α is around 6 and β is around 2°, the motor torque fluctuation and current indicators are at a relatively optimal level, exhibiting good overall performance. Therefore, α≈6° and β≈2° can be considered as the preferred value range, and the parameter step size can be further refined within this range for collaborative optimization to obtain better motor performance. Further experimental verification yielded the following table (Table 4) showing the parameterized matching results of the improved motor 3 gear cutting: Table 4. Results of Parametric Matching for Improved Motor Gear Cutting

[0037] A comparison of the results shown in Table 4 and Table 2 reveals that the motor performance is better when α=6° and β=3°. After gear trimming, the motor torque fluctuation decreased from 11.3% to 7.8%, a reduction of 31.0%; the effective current decreased from 0.527A to 0.523A, a reduction of 0.76%; and the stator iron loss decreased from 98.1mW to 88.1mW. The detailed comparison results of the electromagnetic performance shown in Tables 4 and 2 are as follows:

[0038] Therefore, the central angle α of the target tooth-cutting region at the inner circle of the secondary groove is preferably 6°, and the central angle β of the target tooth-cutting region at the outer circle of the secondary groove is preferably 3°. Figure 4 As shown.

[0039] Example 2: Taking a ratio of 2.8 between the width of the main slot and the secondary slot in the circumferential direction as an example. Assuming the main slot width is 47.9°, accounting for 13.3%, then the secondary slot width is 18.9°, accounting for 5.25%. In this case, the main slot width + 2 secondary slot widths + 2 winding tooth widths = 13.3% + 2 * 5.25% + 2 * 1.51% = 26.82%, which is less than 28.88%. A predetermined step size of 1.5° is selected. The central angle of the stator tooth cutting is selected within the range of 0°-60° for optimization design, resulting in the improved motor 6 tooth cutting scanning results shown in Table 5 below: Table 5. Improved motor 6-tooth cutting scan results

[0040] Table 5 shows that when α is around 4.5° and β is around 0°, the motor torque fluctuation and current indicators are at relatively optimal levels, exhibiting good overall performance. Therefore, α≈4.5° and β≈0° can be considered as the preferred value range, and the parameter step size can be further refined within this range for collaborative optimization to obtain better motor performance. Further experimental verification yielded the following table (Table 6) showing the parameterized matching results of the improved motor 6 tooth cutting: Table 6. Results of Parametric Matching for Improved Motor 6 Tooth Cutting

[0041] A comparison of the results shown in Table 6 and Table 2 reveals that the motor performance is better when α=4.5° and β=0°. After gear trimming, the motor torque fluctuation decreased from 12.0% to 9.8%, a reduction of 18.33%; the effective current decreased from 0.545A to 0.527A, a reduction of 3.3%. The stator iron loss decreased from 97.5mW to 85.6mW. The detailed comparison results of the electromagnetic performance shown in Tables 6 and 2 are as follows:

[0042] Therefore, the central angle α of the target tooth-cutting region at the inner circle of the secondary groove is preferably 4.5°, while the central angle β of the target tooth-cutting region at the outer circle of the secondary groove is preferably 0°. Figure 5 As shown.

[0043] In some embodiments, the method for fabricating the stator structure of the brushless DC pole slot motor further includes step S30, defining three main teeth as a first main tooth, a second main tooth, and a third main tooth in the circumferential direction, respectively, and forming a mounting hole on the first main tooth and the second main tooth, wherein the radius of the mounting hole is 1.1-1.2 mm, and forming a grounding hole on the third main tooth, wherein the length of the grounding hole is 1.15-1.25 mm and the width is 0.62-0.66 mm. By providing mounting holes on the main teeth of the motor stator, the installation requirements between the motor and the gear can be met; by providing grounding holes on the main teeth of the motor stator, the grounding spring on the control board can be eliminated, effectively reducing the cost of the motor.

[0044] refer to Figure 3 The second aspect of this application provides a brushless DC pole slot motor stator structure, including a motor stator body 10. The motor stator body 10 has a plurality of sets of stator slots 101 and a plurality of main teeth 11, and the stator slots 101 and the main teeth 11 are distributed sequentially at intervals in the circumferential direction. The stator slots 101 include main slots 1011 and secondary slots 1012, wherein the secondary slots 1012 are symmetrically distributed on both sides of the main slots 1011 in the circumferential direction, and winding teeth 12 are provided between the main slots 1011 and the secondary slots 1012 in the same set of stator slots 101 for winding motor winding coils. The width of the winding tooth 12 occupies a fixed proportion of 1.51% in the circumferential direction. Simultaneously, the ratio of the width proportions of the main slot 1011 and the auxiliary slot 1012 in the circumferential direction is 1.2-3.2, and the sum of the circumferential proportions of the stator slot 101 and the winding tooth 12 is less than 86.64%. The motor winding coil 13 is wound on adjacent main slots 1011 and auxiliary slots 1012. The stator slot 101, in conjunction with the internal winding coil 13, constitutes one phase of the motor.

[0045] More preferably, the stator slots 101 have three sets, and the main teeth have three, defined circumferentially as a first main tooth 111, a second main tooth 112, and a third main tooth 113. A mounting hole 102 is formed on the first main tooth 111 and the second main tooth 112, wherein the radius of the mounting hole 102 is 1.1-1.2 mm. A grounding hole 103 is formed on the third main tooth 113, and the grounding hole 103 has a length of 1.15-1.25 mm and a width of 0.62-0.66 mm.

[0046] A third aspect of this application provides a brushless DC pole slot motor, including a rotor and a brushless DC pole slot motor stator structure as described above, wherein the motor stator body has a rotor cavity at the central axis, the rotor is located at the center of the rotor cavity, and cooperates with the motor stator body.

[0047] The possible structural forms, manufacturing methods, and corresponding technical effects of brushless DC pole slot motor stator structures and brushless DC pole slot motors have been described in detail above, so they will not be repeated here.

[0048] It should be noted that the terms "first, second, and third" used in this application are for descriptive purposes only, do not indicate any order, and should not be construed as indicating or implying relative importance. These terms can be interpreted as names.

[0049] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. A method for fabricating a stator structure for a brushless DC pole slot motor, characterized in that, The steps are as follows: S10, the stator slots on the motor stator are divided into main slots and auxiliary slots, wherein the auxiliary slots are symmetrically distributed on both sides of the main slots. The stator slots are in several groups and are evenly distributed in the circumferential direction of the motor stator. The teeth between several groups of adjacent stator slots are defined as main teeth, and the teeth between adjacent main slots and auxiliary slots are defined as winding teeth for winding the motor winding coil. The stator slots, together with the internal winding coils, constitute one phase of the motor. The proportion of the circumferential tooth width of the winding teeth is a fixed value of 1.51%. The ratio of the circumferential width of the main slots and the auxiliary slots is 1.2-3.0, and the sum of the circumferential proportions of the stator slots and the winding teeth is less than 80.46%. S20, the secondary slot is subjected to tooth trimming. A tooth trimming area is selected on the side of the secondary slot near the main tooth, wherein the central angle range of the tooth trimming area in the circumferential direction is less than or equal to 6°. The outer circle of the tooth trimming area extends in the same direction as the bottom of the secondary slot. Parametric motor performance verification is performed within a 6° central angle range with a predetermined step size. The target tooth trimming area is selected. After removing the target tooth trimming area, the motor stator structure is obtained. The motor performance includes motor torque fluctuation, effective value of motor current, and motor stator iron loss.

2. The method for fabricating the stator structure of a brushless DC pole slot motor as described in claim 1, characterized in that, The stator slots and the main teeth are each in three sets, and the stator slots and the main teeth are distributed sequentially at intervals.

3. The method for fabricating the stator structure of a brushless DC pole slot motor as described in claim 2, characterized in that, The ratio of the width of the main groove to that of the secondary groove in the circumferential direction is 1.6, and the predetermined step size is 2°.

4. The method for fabricating the stator structure of a brushless DC pole slot motor as described in claim 3, characterized in that, The central angle α of the target tooth-cutting area at the inner circle of the secondary groove is 6°, and the central angle β of the target tooth-cutting area at the outer circle of the secondary groove is 3°.

5. The method for fabricating the stator structure of a brushless DC pole slot motor as described in claim 2, characterized in that, The ratio of the width of the main groove to that of the secondary groove in the circumferential direction is 2.8, and the predetermined step size is 1.5°.

6. The method for fabricating the stator structure of a brushless DC pole slot motor as described in claim 5, characterized in that, The central angle α of the target tooth-cutting area at the inner circle of the secondary groove is 4.5°, and the central angle β of the target tooth-cutting area at the outer circle of the secondary groove is 0°.

7. The method for fabricating the stator structure of a brushless DC pole slot motor as described in any one of claims 2 to 6, characterized in that, The method also includes step S30, which defines the three main teeth as the first main tooth, the second main tooth, and the third main tooth in the circumferential direction, and opens a mounting hole on the first main tooth and the second main tooth respectively, wherein the radius of the mounting hole is 1.1-1.2mm, and opens a grounding hole on the third main tooth, wherein the length of the grounding hole is 1.15-1.25mm and the width is 0.62-0.66mm.

8. The brushless DC pole slot motor stator structure prepared by the method for preparing the brushless DC pole slot motor stator structure according to claim 1, characterized in that, The device includes a motor stator body, which has several sets of stator slots and several main teeth. The stator slots and main teeth are distributed sequentially at intervals in the circumferential direction. The stator slots include main slots and auxiliary slots, which are symmetrically distributed on both sides of the main slots in the circumferential direction. A winding tooth is provided between the main slot and the auxiliary slot in the same set of stator slots. The width of the winding tooth in the circumferential direction accounts for a fixed value of 1.51%. The ratio of the width of the main slot and the auxiliary slot in the circumferential direction is 1.2-3.2, and the sum of the circumferential proportions of the stator slot and the winding tooth is less than 86.64%. The motor winding coil is wound on adjacent main slots and auxiliary slots. The stator slot and the internal winding coil constitute one phase of the motor.

9. The stator structure of the brushless DC pole slot motor as described in claim 8, characterized in that, The stator slots are in three sets, and the main teeth are in three sets. The three main teeth are defined as the first main tooth, the second main tooth, and the third main tooth in the circumferential direction. A mounting hole is opened on the first main tooth and the second main tooth, wherein the radius of the mounting hole is 1.1-1.2 mm. A grounding hole is opened on the third main tooth, wherein the length of the grounding hole is 1.15-1.25 mm and the width is 0.62-0.66 mm.

10. A brushless DC pole slot motor, characterized in that, It includes a rotor and a brushless DC pole slot motor stator structure as described in claim 8 or 9, wherein the motor stator body has a rotor cavity at the central axis, the rotor is located at the center of the rotor cavity, and cooperates with the motor stator body.

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