Stator core with multi-order harmonic cancellation function, processing system, processing technology and axial flux motor

Abstract

The application discloses a stator core with multi-order harmonic cancellation function, a processing system, a processing technology and an axial flux motor, and belongs to the field of stator cores. The stator core is formed by stamping metal strip and continuously winding along a planar spiral line, and each layer is tightly attached and solidified to form a disc-shaped laminated structure. The metal strip has a first side and a second side extending along the length direction. A plurality of winding arrangement grooves are arranged at intervals along the length direction on the first side. Adjacent winding arrangement grooves form stator teeth. At least one tooth top groove is integrally stamped at the middle position of the tooth top of the stator tooth. The circumferential distance between the tooth top groove and the corresponding winding arrangement groove is constant. After the metal strip is wound and formed, the same tooth top groove forms a continuous circumferential offset inclined structure along the radial direction of the stator, which forms a tooth top inclined groove. Multi-order air gap harmonic synchronous cancellation is realized through radial continuous phase gradient. The stator core with multi-order harmonic cancellation function, the processing system, the processing technology and the axial flux motor have excellent electromagnetic performance and large-scale production process, and the torque ripple reduction amplitude can reach 46.3% and the motor efficiency does not attenuate under the same working condition. The application is suitable for various axial flux motor scenes with high stability requirements.

Description

Technical Field

[0001] This invention relates to the field of stator core technology, and in particular to a stator core with multi-order harmonic cancellation function, a processing system, a processing technology, and an axial flux motor. Background Technology

[0002] Axial flux permanent magnet motors possess advantages such as short axial dimension, high power density, outstanding torque density, and compact structure, making them widely used in confined installation spaces such as new energy vehicles, industrial servos, aerospace, and wind power generation. However, the uneven distribution of air gap magnetic permeability along the circumference in these motors, coupled with the coupling between the permanent magnet magnetic field and the stator slot structure, generates significant cogging torque and torque pulsation, inducing generator vibration and electromagnetic noise, reducing low-speed control accuracy, and limiting their application in precision transmission fields.

[0003] Currently, adding auxiliary slots at the stator tooth tips is the mainstream low-cost solution for reducing cogging torque and optimizing air gap magnetic field harmonics, and extensive theoretical and simulation studies have been conducted in the industry. However, existing technologies have two major drawbacks: Firstly, existing research and applications all use a straight groove structure at the tooth tip. The straight groove can only cancel out air gap magnetic permeability harmonics of a single specific order. The harmonic suppression bandwidth is narrow, and there is a theoretical upper limit to the reduction of tooth groove torque. It cannot simultaneously cancel out multiple harmful harmonics, and the torque pulsation suppression effect is limited.

[0004] Secondly, existing tooth top groove solutions are all adapted to segmented stacked stator cores, and can only pre-stamp straight tooth top grooves on a single lamination. However, the mainstream mass production solution for axial flux motors is a continuous silicon steel strip planar spiral wound stator. If the existing technology route is used for ground-wound cores, there are multiple engineering defects: First, after winding, secondary milling or laser grooving is required. The narrow tooth top space makes it difficult to guarantee processing accuracy and easily causes silicon steel sheet delamination, burrs, and thermal damage, resulting in poor consistency of batch products. Second, there are many production processes and long production line cycle times, and processing waste increases material costs. Third, secondary grooving will cut off the continuous silicon steel layer at the tooth top, causing local stress concentration. Under high-speed conditions, the teeth are prone to deformation and delamination, reducing the service life of the stator and the stability of electromagnetic performance. Summary of the Invention

[0005] The purpose of this invention is to provide a stator core with multi-order harmonic cancellation function, a processing system, a processing technology, and an axial flux motor, thereby solving the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides a stator core with multi-order harmonic cancellation function. It is formed by continuously winding a metal strip along a planar spiral after stamping, and then tightly bonding and solidifying each layer to form a disc-shaped stacked structure. The metal strip has a first side and a second side extending along the length direction. The first side is provided with multiple winding placement slots at intervals along the length direction. The adjacent winding placement slots form stator teeth. At least one tooth tip groove is integrally stamped at the middle position of the tooth tip of the stator teeth. The circumferential distance between the tooth tip groove and the corresponding winding placement slot is constant. After the metal strip is wound and formed, the same tooth tip groove forms a continuously circumferentially offset inclined structure along the stator radial direction, forming a tooth tip inclined groove. Multi-order air gap harmonics are synchronously canceled through a continuous radial phase gradient.

[0007] Preferably, the tooth tip skew groove forms a continuous and smooth circumferential phase offset gradient along the stator radial direction, corresponding to the tooth tip skew groove torque. Slot attenuation factor of air gap magnetic permeability harmonics satisfy: ; ; ; ; In the formula, This indicates the angle that changes along the direction of motor rotation. , These are the weighting coefficients for the influence of the tooth tip groove width and groove depth on the torque, respectively. Let be the distribution function of the length along the circumference of the magnetization direction of the permanent magnet. This represents the initial angular position of the motor. The effective air gap length of the motor. The total number of slots in the stator core. Number of stator slots The least common multiple of the number of poles of the motor. The width of the tooth tip groove. This is the equivalent width at the tooth tip. The depth of the tooth tip groove. This refers to the stator tooth height. When there is no skew groove, Secondary air gap magnetic permeability harmonic Fourier decomposition amplitude; The tooth tip groove width is the dominant factor. Integral function for subharmonic attenuation; The tooth top groove depth and stator tooth height are the main factors. Integral function for subharmonic attenuation; The order of the air gap cogging torque harmonic; The tooth tip groove uses a radially continuous phase offset gradient to cancel out the phase misalignment of harmonics of the same order generated at different radial positions, thus synchronously attenuating low-order and high-order tooth groove harmonics.

[0008] Preferably, the distance from the centerline of the tooth tip slot to the centerline of the corresponding winding mounting slot is And it satisfies the following range of values: ; Tooth top groove width Satisfies the range of values: ; Tooth top groove depth Satisfies the range of values: ; in, Let be the winding radius of any layer in the stacked structure. To determine the slot width for the winding, This refers to the axial length of the stator core. After the metal strip is wound into shape, the inclination angle of the tooth tip groove is: .

[0009] Preferably, the metal strip is a silicon steel strip for motors. After winding, the first side of the metal strip forms an annular disc with stator teeth, and the second side forms an annular stator yoke connecting all the stator teeth. Each layer of metal strip is fixed into an integral structure by one or more of the following methods: pressing, welding, riveting, bonding, and impregnation curing. The slot type of the winding placement slot and the tooth tip slot is any one or more combinations of rectangular slot, trapezoidal slot, V-shaped slot, U-shaped slot, circular arc slot, chamfered slot, stepped slot, and composite slot; The tooth tip groove can be a single groove structure, a multi-groove parallel structure, or a segmented groove structure. The multi-groove structure can be arranged symmetrically or asymmetrically along the tooth width direction.

[0010] Preferably, the stator core is divided into at least two continuous sections along the radial direction; For any radial segment, the winding radius Center distance of tooth tip groove Groove width trench depth The following radial fit design formula must be satisfied: Design formula for center distance of tooth tip groove: ; Design formula for tooth groove width: ; Tooth tip groove depth design formula: ; in, For the radius of The distance between the center line of the tooth tip groove corresponding to the radial layer and the center line of the winding mounting groove. For the winding radius is The width of the tooth tip groove corresponding to the radial layer, For the winding radius is The radial layer corresponds to the tooth tip groove depth. This is the extreme number correction factor. This is the air gap length correction factor. This is the thickness correction factor for the permanent magnet. This is the tooth width adaptation coefficient. For the rated air gap magnetic flux density, For the target operating point magnetic flux density, The initial value of the reference groove depth, The outer diameter of the stator core, This is the stator tooth width correction factor. This is a correction factor for the stator yoke thickness. The equivalent radius of the radial segment of the stator winding; Center distance of tooth top groove Groove width trench depth Based on the number of motor poles, number of slots, air gap length, permanent magnet thickness, tooth width, yoke thickness, and target operating point, global parameter optimization is completed to adapt to the differences in high and low order harmonic distribution at different radial positions, and to achieve multi-order harmonic global coordinated cancellation.

[0011] A processing system for processing stator cores with multi-order harmonic cancellation function includes a stamping mechanism and a winding mechanism. The stamping mechanism is equipped with a punch and a die. The lower end of the punch has a cutting edge profile that matches the forming profile of the winding mounting groove and the tooth tip groove. The winding mounting groove and the tooth tip groove are formed in one piece simultaneously in a single stamping.

[0012] Preferably, the punch is a split-joint assembly structure, including a first sub-punch with a stamping winding mounting slot and a second sub-punch with a stamping tooth top slot; The punch cutting edge is provided with an inverted cone structure along the axial direction, and the inverted cone angle is 1°; The punch has a Rockwell hardness of HRC58-62 after heat treatment and quenching. The tail of the punch is equipped with a mounting platform positioning structure that cooperates with the clamping plate of the stamping machine.

[0013] Preferably, the present invention further includes a winding control unit, which is electrically connected to the stamping mechanism and the winding mechanism respectively. The winding control unit includes a displacement sensor, an angle encoder and a control module. The displacement sensor collects the displacement of the metal strip in real time, the angle encoder collects the rotation angle of the winding spindle in real time, and the control module is used to dynamically adjust the stamping spacing based on the real-time winding radius to ensure that the stator teeth of each layer are circumferentially aligned and the tilt angle of the tooth tip groove is uniform after winding. The formula for adjusting the stamping spacing is as follows: ; in, ; In the formula, Current winding radius The corresponding target stamping spacing, For the first The current real-time winding radius corresponding to the layer of steel strip. The initial inner diameter of the stator core. The number of circles. The thickness of a single layer of metal strip.

[0014] The manufacturing process of a stator core with multi-harmonic cancellation function includes the following steps: S1. Substrate preparation: Provide a metal strip of a preset width; wherein, the metal strip is divided along its length into a first side corresponding to the axial height of the stator teeth and a second side corresponding to the axial height of the stator yoke; S2, Integrated stamping: A punch is used to simultaneously stamp the winding mounting slot and tooth top slot on the first side of the metal strip. Stator teeth are formed between adjacent winding mounting slots, and the distance between the tooth top slot and the corresponding winding mounting slot remains constant. S3, Planar spiral winding: The stamped metal strip is wound into a disc-shaped structure along a planar spiral line. The straight dimension of the flat strip is converted into the circumferential arc length. The tooth tip grooves with a fixed spacing change with the winding radius to form a tooth tip groove that is continuously inclined in the radial direction. S4. Lamination and curing: The wound disc structure is fixed to ensure that the metal strips are tightly bonded together to form an integral stator core. Step S3 specifically includes the following steps: S31. Initialization: Set the initial inner diameter of the stator core. , outer diameter Total number of slots in stator core single-layer thickness of metal strip Initial winding radius Initial target stamping spacing , send displacement Reset to zero; S32. Real-time monitoring and updating: Drives the metal strip forward and collects the feed displacement in real time. and the rotation angle of the winding spindle Calculate the current winding radius And update the target stamping spacing simultaneously. ; S33, Stamping Trigger: When the displacement is fed in... Achieve the current target stamping spacing At that time, the trigger punch completes one stamping cycle and is fed into the displacement. Reset to zero; S34. Cyclic processing: Repeat steps S32-S33 until the winding radius is reached. Reaching outer diameter Complete the stamping of all tooth grooves.

[0015] An axial flux motor includes a stator core with multi-order harmonic cancellation function and a rotor assembly with permanent magnets. The permanent magnets of the rotor assembly have a flat plate structure. The permanent magnets cooperate with the stator tooth tip slots to form a nonlinear air gap, which simultaneously suppresses multi-order tooth cogging harmonics and torque pulsation.

[0016] Therefore, the present invention employs the above-mentioned stator core with multi-order harmonic cancellation function, processing system, processing technology, and axial flux motor, which has the following beneficial effects: 1. Multi-order harmonic synchronous cancellation, significantly improving electromagnetic performance: This invention uses automatically formed tooth tip oblique slots to create a continuous circumferential phase gradient along the stator radial direction. This effectively divides a single tooth radially into countless differential segments. The phase misalignment of harmonics of the same order generated by different segments cancels each other out, simultaneously covering multiple types of low-order and high-order air gap harmonics. This overcomes the technical bottleneck of traditional straight tooth tip slots, which can only cancel single-order harmonics and have a narrow suppression bandwidth. Simulation verification shows that under the same operating conditions, the torque pulsation of this solution is reduced by approximately 46.3% compared to the slotless solution, with no reduction in motor efficiency, and significantly improved low-speed operation stability and noise performance. It also supports radially partitioned differentiated slot parameter design, allowing for precise optimization of the magnetic field characteristics of the inner and outer diameters to maximize the global harmonic suppression effect. 2. Integrated stamping process significantly improves mass production consistency and processing efficiency: This invention uses a single stamping operation to simultaneously form the winding mounting slot and tooth tip slot, completely eliminating the traditional secondary grooving process for winding stators and fundamentally preventing processing defects such as silicon steel delamination, burrs, and thermal damage. Combined with a variable-pitch stamping control strategy, the stamping pitch can be dynamically adjusted according to the winding radius. After winding, all stator teeth and tooth tip slots are automatically and precisely aligned circumferentially, eliminating the need for subsequent positioning correction. This significantly improves the dimensional consistency and yield of batch products, shortens production line cycle time, and is suitable for large-scale industrial mass production. 3. Complete and reliable structure with excellent mechanical properties: The stator teeth and tooth top grooves are integral stamped structures, eliminating the cutting of silicon steel strips and structural damage caused by secondary grooving. The tooth structure is continuous and complete, with no local stress concentration points. It is not easy to deform and delaminate under high-speed conditions, significantly improving the mechanical strength and service life of the stator core. At the same time, it avoids the risk of long-term vibration and loosening of the split tooth shoes. 4. Low cost and high flexibility in magnetic field optimization: This solution eliminates the need for expensive components such as irregularly shaped permanent magnets and split toothed shoes. Harmonic suppression can be achieved solely through topology optimization of the tooth crest slot, resulting in significantly lower manufacturing costs compared to existing solutions. Furthermore, by adjusting parameters such as slot shape, slot width, slot depth, and offset, the air gap magnetic flux density waveform can be optimized independently or collaboratively to specifically suppress specific order harmonics and adapt to different pole-slot combinations and performance requirements.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the processing of the stator core of the present invention; Figure 2 This is a schematic diagram of the stamping process of the stator core of the present invention; Figure 3 This is a schematic diagram of the winding of the stator core of the present invention; Figure 4 This is a comparison curve of the load torque of the stator core in Example 1 and the prior art.

[0019] Figure Labels 1. Metal strip, 2. Punch, 3. Die, 4. Stator teeth, 5. Winding mounting slot, 6. Tooth top slot, 7. Annular stator yoke. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0021] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] Example 1 This embodiment provides a stator core with a single-parameter tooth tip oblique groove, a matching machining system, and a machining process, as detailed below: 1. Stator core structure like Figure 3 As shown, the stator core in this embodiment is a disc-shaped stacked structure, which is formed by continuously winding a continuous motor silicon steel metal strip 1 along a planar spiral, with each layer tightly bonded and then laser-welded and cured. The metal strip 1 has a first side and a second side extending along the length direction. After winding, the first side forms an annular disc surface with uniformly distributed stator teeth 4, and the second side forms an annular stator yoke 7 connecting all stator teeth 4.

[0024] like Figure 2 As shown, in its flat, unfolded state, the first side of the metal strip 1 has multiple winding mounting slots 5 stamped at intervals along its length. The protrusions between adjacent winding mounting slots 5 are stator teeth 4. Each stator tooth 4 has a rectangular tooth tip groove 6 integrally stamped on its tooth tip. The tooth tip groove 6 is parallel to the strip feeding direction, and the distance from its center line to the center line of the corresponding winding mounting slot 5 is... The width of the tooth tip groove 6 is constant throughout the entire stroke. The depth of the groove is .

[0025] During the winding process of metal strip 1, the straight dimensions in a flat state are transformed into arc lengths in the circumferential direction. Since the distance d between the tooth tip groove 6 and the winding mounting groove 5 remains constant, the same tooth tip groove 6 gradually shifts circumferentially from the inner diameter to the outer diameter of the stator, eventually forming a continuous inclined tooth tip groove with an inclination angle of . .

[0026] The tooth tip groove forms a continuous circumferential phase gradient along the radial direction. When the rotor permanent magnet sweeps across the stator tooth tip, the same-order tooth cogging harmonics generated at different radial positions have a phase difference and cancel each other out after superposition. At the same time, low-order and high-order air gap harmonics will all have amplitude attenuation due to the continuous phase gradient, realizing the synchronous cancellation of multiple harmonics and greatly reducing tooth cogging torque and torque pulsation.

[0027] 2. Machining System Structure The processing system in this embodiment includes a composite stamping punch 2, a die 3, and a winding control unit.

[0028] like Figure 1 and Figure 2 As shown, the composite stamping punch 2 is a split-assembly structure, including a first sub-punch 21 for forming the winding mounting groove 5 and a second sub-punch 22 for forming the tooth top groove 6. Both sub-punches have a mounting platform structure at their tails and are assembled to the press clamp by insert fixing, completing the stamping action synchronously. The lower end cutting edge contour of the punch 2 is perfectly matched with the design contour of the winding mounting groove 5 and the tooth top groove 6, and the two types of grooves can be formed in one piece simultaneously with a single press.

[0029] The punch has a 1° inverted cone structure along the axial direction on the second cutting edge to ensure that the silicon steel stamping section is flat and free of material burrs; after heat treatment and quenching, the Rockwell hardness of the punch is controlled at HRC58-62, taking into account both the wear resistance and fracture strength of the cutting edge.

[0030] The winding control unit includes a displacement sensor, an angle encoder, and a control module. The displacement sensor collects the feed displacement of the metal strip 1 in real time, the angle encoder monitors the rotation angle of the winding spindle in real time, and the control module calculates the current winding radius in real time based on the number of turns wound and the strip thickness, updates the target stamping spacing synchronously, and accurately triggers the stamping action to ensure that the stator teeth of each layer are circumferentially aligned after winding.

[0031] 3. Processing steps The stator core processing technology in this embodiment includes the following steps: S1. Substrate preparation: Select electrical silicon steel metal strip 1 with a preset width. The width of the strip is equal to the total axial height of the stator core. The width on the first side corresponds to the axial height of the stator teeth 4, and the width on the second side corresponds to the axial height of the annular stator yoke 7.

[0032] S2. Integrated stamping: The metal strip 1 is fed into a continuous stamping die. The punch 2 and the die 3 cooperate to form the winding mounting groove 5 and the tooth top groove 6 on the first side of the metal strip 1 in a single stamping. Stator teeth 4 are formed between adjacent winding mounting grooves 5. The distance between the tooth top groove 6 and the corresponding winding mounting groove 5 is maintained throughout the process. Constant. This embodiment uses the same set of fixed parameters for the punch throughout the entire process, and the parameters of the tooth top groove 6 are consistent at all radial positions.

[0033] S3. Planar spiral winding: The stamped metal strip 1 is fed into the planar winding device and wound into a disc-shaped structure along the preset planar spiral trajectory. During the winding process, a variable spacing stamping control strategy is adopted to dynamically adjust the stamping spacing to ensure that the stator teeth 4 of each layer are precisely aligned in the circumference after winding. The tooth top groove 6 with a fixed spacing forms a tooth top inclined groove that is continuously inclined in the radial direction as the winding radius increases.

[0034] S4. Lamination and curing: After winding, laser welding is used to reinforce the weld seam on the outer edge of the stator, so that the metal strips of each layer are tightly bonded into a whole, and the stator core of the tooth-top slotted axial flux motor is obtained.

[0035] 4. Performance Verification Under the same input power and motor size conditions, a load torque simulation comparison was performed on the stator core of this embodiment and the conventional stator core without toothed top slots. The results are as follows: Figure 4 As shown, the torque ripple of the conventional slotless design is 5.59%, while the torque ripple of the tooth-top skewed slot design in this embodiment is only 3.00%, a reduction of approximately 46.3%, with no decrease in motor output efficiency. This verifies that this design can significantly suppress load torque fluctuations and improve motor operating stability by canceling out multiple harmonics while ensuring efficiency.

[0036] Example 2 This embodiment is basically the same as the core structure and processing flow of Embodiment 1. The difference lies in the adoption of a radially partitioned differentiated tooth tip groove design to further improve the global harmonic suppression effect. The specific scheme is as follows: Pre-determine the radial range (inner diameter) of the stator core To outer diameter ) divided into A continuous segment, ; Optimize the parameters of the tooth tip groove independently for each section. , , To prepare a special punch with corresponding parameters.

[0037] During the winding process, the control system calculates the current winding radius in real time. Determine the radial segment to which it belongs; when winding transitions from one segment to the next, replace the special punch with the corresponding parameters and continue to perform the stamping and winding actions.

[0038] The final stator core features differentiated tooth tip skew parameters in different radial sections: the inner diameter section has lower magnetic flux density and is dominated by low-order harmonics, matching slot parameters for low-order harmonic suppression; the outer diameter section has higher magnetic flux density and is dominated by high-order harmonics, matching slot parameters for high-order harmonic suppression. Compared to single-parameter tooth tip skew, this partitioned differentiated design can more accurately adapt to the differences in radial magnetic field distribution, achieving global fine-tuning of the air gap magnetic field across the entire radial range, further reducing overall tooth cogging torque and torque pulsation.

[0039] In other embodiments, the groove shape of the tooth tip groove can be replaced with various contours such as trapezoidal, V-shaped, U-shaped, arc, segmented, etc., and can be integrally formed by replacing the punch with the corresponding cutting edge. All of these can achieve the same multi-order harmonic cancellation effect and are all within the protection scope of this invention.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A stator core with multi-harmonic cancellation function, comprising a disc-shaped laminated structure formed by continuously winding metal strip along a planar spiral after stamping, with each layer tightly bonded and solidified, wherein the metal strip has a first side and a second side extending along the length direction, the first side having multiple winding mounting slots spaced apart along the length direction, and adjacent winding mounting slots forming stator teeth, characterized in that: At least one tooth tip groove is integrally stamped at the middle position of the stator tooth tip, and the circumferential distance between the tooth tip groove and the corresponding winding mounting groove is constant. After the metal strip is wound and formed, the same tooth tip groove forms a continuously circumferentially offset inclined structure along the stator radial direction, which constitutes a tooth tip inclined groove. Multi-order air gap harmonic synchronous cancellation is achieved through radial continuous phase gradient.

2. The stator core with multi-harmonic cancellation function according to claim 1, characterized in that: The tooth tip helical groove forms a continuous and smooth circumferential phase offset gradient along the stator radial direction, corresponding to the tooth tip helical groove torque. Slot attenuation factor of air gap magnetic permeability harmonics satisfy: ； ； ； ； In the formula, This indicates the angle that changes along the direction of motor rotation. , These are the weighting coefficients for the influence of the tooth tip groove width and groove depth on the torque, respectively. Let be the distribution function of the length along the circumference of the magnetization direction of the permanent magnet. This represents the initial angular position of the motor. The effective air gap length of the motor. The total number of slots in the stator core. Number of stator slots The least common multiple of the number of poles of the motor. The width of the tooth tip groove. This is the equivalent width at the tooth tip. The depth of the tooth tip groove. This refers to the stator tooth height. When there is no skew groove, Secondary air gap magnetic permeability harmonic Fourier decomposition amplitude; The tooth tip groove width is the dominant factor. Integral function for subharmonic attenuation; The tooth top groove depth and stator tooth height are the main factors. Integral function for subharmonic attenuation; The order of the air gap cogging torque harmonic; The tooth tip groove uses a radially continuous phase offset gradient to cancel out the phase misalignment of harmonics of the same order generated at different radial positions, thus synchronously attenuating low-order and high-order tooth groove harmonics.

3. The stator core with multi-harmonic cancellation function according to claim 1, characterized in that: The distance from the centerline of the tooth top slot to the centerline of the corresponding winding mounting slot is And it satisfies the following range of values: ; Tooth top groove width Satisfies the range of values: ; Tooth top groove depth Satisfies the range of values: ; in, Let be the winding radius of any layer in the stacked structure. To determine the slot width for the winding, This refers to the axial length of the stator core. After the metal strip is wound into shape, the inclination angle of the tooth tip groove is: .

4. The stator core with multi-harmonic cancellation function according to claim 1, characterized in that: The metal strip is a silicon steel strip for motors. After winding, the first side of the metal strip forms an annular disc with stator teeth, and the second side forms an annular stator yoke connecting all the stator teeth. Each layer of metal strip is fixed into an integral structure by one or more of the following methods: pressing, welding, riveting, bonding, and impregnation curing. The slot type of the winding placement slot and the tooth tip slot is any one or more combinations of rectangular slot, trapezoidal slot, V-shaped slot, U-shaped slot, circular arc slot, chamfered slot, stepped slot, and composite slot; The tooth tip groove can be a single groove structure, a multi-groove parallel structure, or a segmented groove structure. The multi-groove structure can be arranged symmetrically or asymmetrically along the tooth width direction.

5. The stator core with multi-harmonic cancellation function according to claim 1, characterized in that: The stator core is divided into at least two continuous sections along the radial direction; For any radial segment, the winding radius Center distance of tooth tip groove Groove width trench depth The following radial fit design formula must be satisfied: Design formula for center distance of tooth tip groove: ; Design formula for tooth groove width: ; Tooth tip groove depth design formula: ; in, For the radius of The distance between the center line of the tooth tip groove corresponding to the radial layer and the center line of the winding mounting groove. For the winding radius is The width of the tooth tip groove corresponding to the radial layer, For the winding radius is The radial layer corresponds to the tooth tip groove depth. This is the extreme number correction factor. This is the air gap length correction factor. This is the thickness correction factor for the permanent magnet. This is the tooth width adaptation coefficient. For the rated air gap magnetic flux density, For the target operating point magnetic flux density, The initial value of the reference groove depth, The outer diameter of the stator core, This is the stator tooth width correction factor. This is a correction factor for the stator yoke thickness. The equivalent radius of the radial segment of the stator winding; Center distance of tooth top groove Groove width trench depth Based on the number of motor poles, number of slots, air gap length, permanent magnet thickness, tooth width, yoke thickness, and target operating point, global parameter optimization is completed to adapt to the differences in high and low order harmonic distribution at different radial positions, and to achieve multi-order harmonic global coordinated cancellation.

6. A processing system for processing a stator core with multi-harmonic cancellation function as described in any one of claims 1-5, comprising a stamping mechanism and a winding mechanism, characterized in that: The stamping mechanism is equipped with a punch and a die. The lower end of the punch has a cutting edge profile that matches the forming profile of the winding mounting groove and the tooth top groove. The winding mounting groove and the tooth top groove are formed in one piece simultaneously in a single stamping.

7. The processing system according to claim 6, characterized in that: The punch is a split and assembled structure, including a first sub-punch with a stamping winding mounting slot and a second sub-punch with a stamping tooth top slot; The punch cutting edge is provided with an inverted cone structure along the axial direction, and the inverted cone angle is 1°; The punch has a Rockwell hardness of HRC58-62 after heat treatment and quenching. The tail of the punch is equipped with a mounting platform positioning structure that cooperates with the clamping plate of the stamping machine.

8. The processing system according to claim 6, characterized in that: It also includes a winding control unit, which is electrically connected to the stamping mechanism and the winding mechanism respectively. The winding control unit includes a displacement sensor, an angle encoder and a control module. The displacement sensor collects the displacement of the metal strip in real time, the angle encoder collects the rotation angle of the winding spindle in real time, and the control module is used to dynamically adjust the stamping spacing based on the real-time winding radius to ensure that the stator teeth of each layer are circumferentially aligned and the tilt angle of the tooth tip groove is uniform after winding. The formula for adjusting the stamping spacing is as follows: ； in, ； In the formula, Current winding radius The corresponding target stamping spacing, For the first The current real-time winding radius corresponding to the layer of steel strip. The initial inner diameter of the stator core. The number of circles. The thickness of a single layer of metal strip.

9. The processing technology of a stator core with multi-harmonic cancellation function as described in any one of claims 1-5, characterized in that: Includes the following steps: S1. Substrate preparation: Provide a metal strip of a preset width; wherein, the metal strip is divided along its length into a first side corresponding to the axial height of the stator teeth and a second side corresponding to the axial height of the stator yoke; S2, Integrated stamping: A punch is used to simultaneously stamp the winding mounting slot and tooth top slot on the first side of the metal strip. Stator teeth are formed between adjacent winding mounting slots, and the distance between the tooth top slot and the corresponding winding mounting slot remains constant. S3, Planar spiral winding: The stamped metal strip is wound into a disc-shaped structure along a planar spiral line. The straight dimension of the flat strip is converted into the circumferential arc length. The tooth tip grooves with a fixed spacing change with the winding radius to form a tooth tip groove that is continuously inclined in the radial direction. S4. Lamination and curing: The wound disc structure is fixed to ensure that the metal strips are tightly bonded together to form an integral stator core. Step S3 specifically includes the following steps: S31. Initialization: Set the initial inner diameter of the stator core. , outer diameter Total number of slots in stator core single-layer thickness of metal strip Initial winding radius Initial target stamping spacing , send displacement Reset to zero; S32. Real-time monitoring and updating: Drives the metal strip forward and collects the feed displacement in real time. and the rotation angle of the winding spindle Calculate the current winding radius And update the target stamping spacing simultaneously. ; S33, Stamping Trigger: When the displacement is fed in... Achieve the current target stamping spacing At that time, the trigger punch completes one stamping cycle and is fed into the displacement. Reset to zero; S34. Cyclic processing: Repeat steps S32-S33 until the winding radius is reached. Reaching outer diameter Complete the stamping of all tooth grooves.

10. An axial flux motor, characterized in that: The invention includes a stator core with multi-order harmonic cancellation function and a rotor assembly with permanent magnets as described in any one of claims 1-5, wherein the permanent magnets of the rotor assembly have a flat plate structure, and the permanent magnets cooperate with the stator tooth tip slots to form a nonlinear air gap, thereby simultaneously suppressing multi-order tooth cogging harmonics and torque pulsation.

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