Slotting method and slotting structure of asynchronous motor stator tooth part and asynchronous motor

Abstract

The invention relates to a slotting method and a slotting structure for a stator tooth part of an asynchronous motor and the asynchronous motor, and the method comprises the steps: obtaining NVH actual measurement data of a first prototype, and obtaining electromagnetic forces of a first order and a second order of the first prototype according to the NVH actual measurement data; acquiring the peak torque of the first prototype; preparing a second prototype; the peak torque of each second prototype is obtained in sequence; if the ratio is greater than or equal to the preset value, acquiring first-order and second-order electromagnetic forces of the second prototype, and judging whether the electromagnetic forces are smaller than the first prototype; if yes, verifying to be qualified; and comparing all the second prototypes with qualified auxiliary grooves, and determining one of the second prototypes as optimization design. According to the method, the problem that NVH optimization cannot be efficiently guided due to the fact that the difference between the coupling electromagnetic force order and the like between the stator and the rotor in theory and the actual situation is large can be effectively solved by adopting an objective test result as the criterion and guiding the thought of simulation calculation, and the purpose of accurately improving first-order and second-order howling of the asynchronous motor is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of asynchronous motors, and particularly to a slotting method, a slotting structure and an asynchronous motor for the stator teeth of an asynchronous motor. Background Art

[0002] New energy vehicles can be equipped with asynchronous motors. An asynchronous motor, also known as an induction motor, has the characteristics of simple structure, no demagnetization problem, convenient manufacturing, use and maintenance. An asynchronous motor can include a stator and a rotor. The stator can include an armature winding and a magnetic conducting core. When a symmetrical three-phase positive sine current with a specific frequency f1 is input into the armature winding of the stator, a rotating magnetic field with a speed n1 is generated in the air gap between the stator and the rotor. The rotor can include a cage winding and a magnetic conducting core. The cage winding and the rotating magnetic field of the stator move relative to each other, generating an induced electromotive force and an induced current in the cage winding of the rotor. Further, the rotating magnetic field of the stator and the current of the rotor interact with each other to generate an electromagnetic torque, enabling the rotor to obtain a corresponding speed n. The speed n1 of the stator magnetic field and the speed n of the rotor magnetic field always maintain a difference, so it is called an asynchronous motor. The slip ratio s of an asynchronous motor is the difference (n1 - n) between the speed n1 of the rotating magnetic field generated after a symmetrical three-phase current with a fixed frequency f1 is input into the stator and the speed n of the magnetic field generated by the induced current in the closed winding of the rotor. The ratio (n1 - n) / n1 of the speed difference to the stator speed is defined as the slip ratio s. According to the value of the slip ratio s, the operating state of the asynchronous motor at any time can be directly judged, mainly including the generator operating state (S < 0), the motor operating state (0 < S1 < 1), and the electromagnetic braking state (S > 1).

[0003] The stator of an asynchronous motor can have the same structure as that of a traditional synchronous motor. Its main function is to generate a rotating magnetic field after three-phase alternating current is applied. The main characteristic of the rotor of an asynchronous motor is its cage structure, which is cast by a casting aluminum process. It has the advantages of simple structure, no use of rare earth elements, and no demagnetization risk. Through the speed difference between the stator magnetic field speed and the rotor speed, an induced electromotive force and an induced current are formed in the cage winding of the rotor, further generating a rotating magnetic field of the rotor itself. The stator magnetic field and the rotor magnetic field interact with each other through coupling to generate an electromagnetic force, completing the conversion and output of electrical energy into mechanical energy. The electromagnetic force is a pair of interaction forces generated by the coupling of the stator magnetic field and the rotor induced magnetic field. The stator end acts on parts such as the stator slots and the stator windings, which is the main source of stator orders; the rotor end mainly acts on the rotor cage bar ends and the rotor bar slots, which is the source of rotor end orders. Further, according to the direction of the electromagnetic force, the electromagnetic force can be divided into an axial electromagnetic force parallel to the rotor shaft, a radial electromagnetic force in the radius direction of the rotor cross-section, and a tangential electromagnetic force.

[0004] Radial electromagnetic force is the primary adjustment point when magnetic order issues arise in asynchronous motors. Reducing this radial electromagnetic force can effectively improve the NVH performance of asynchronous motors. Adjustment of the radial electromagnetic force can include slotting the stator teeth. However, when calculating the corresponding electromagnetic force in an asynchronous motor, factors such as slip must be considered because the rotor lacks a permanent magnet magnetic field. The theoretical order of the coupled electromagnetic force between the stator and rotor differs significantly from the actual value, making it ineffective in guiding NVH optimization. This means it cannot provide a reference for slotting the stator teeth. Summary of the Invention

[0005] Based on this, the present application provides a slotting method, slotting structure and asynchronous motor for the stator teeth of an asynchronous motor, so as to improve the problem in the prior art that the asynchronous motor cannot efficiently guide NVH optimization due to the large difference between the theoretical order of the coupling electromagnetic force between the stator and rotor and the actual one.

[0006] In a first aspect, the present application provides a method for slotting stator teeth of an asynchronous motor, the method comprising:

[0007] Obtaining NVH measured data of a first prototype of an asynchronous motor, and obtaining first-order and second-order electromagnetic forces of the first prototype based on the NVH measured data of the first prototype; wherein the asynchronous motor includes a stator and a rotor, the rotor of the asynchronous motor includes m rotor slots, the number of poles of a magnetic field formed by the rotor is n, the first order is mn order, the second order is m order, and no slots are formed on the stator teeth of the first prototype;

[0008] Acquiring external characteristic data of the first prototype, and acquiring a peak torque of the first prototype based on the external characteristic data of the first prototype;

[0009] Prepare a second prototype of the asynchronous motor, wherein the stator teeth of the second prototype are provided with auxiliary slots; and the auxiliary slots are arranged into a plurality of different groups to form a plurality of the second prototypes;

[0010] Obtaining external characteristic data of each second prototype in sequence, and obtaining a peak torque of each second prototype based on the external characteristic data of each second prototype; if a ratio of the peak torque of the second prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the second prototype, and determining whether the first-order and second-order electromagnetic forces of the second prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot of the second prototype is qualified;

[0011] The first-order and second-order electromagnetic forces of all the second prototypes with qualified auxiliary slots are compared, and the auxiliary slot of the second prototype with relatively small first-order and second-order electromagnetic forces is determined as the optimized design.

[0012] In one embodiment, a second prototype of the asynchronous motor is prepared, wherein auxiliary slots are provided on the stator teeth of the second prototype; and the auxiliary slots are arranged in a plurality of different groups to form a plurality of second prototypes, including:

[0013] preparing a second prototype of the asynchronous motor, wherein the auxiliary slots are provided on the stator teeth of the second prototype; arranging the auxiliary slots into a plurality of different groups according to the shapes of the auxiliary slots to form a plurality of the second prototypes;

[0014] Comparing the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots are qualified, and determining as an optimized design the auxiliary slot of the second prototype whose first-order and second-order electromagnetic forces are both relatively small, comprising:

[0015] The first-order and second-order electromagnetic forces of all the second prototypes with qualified auxiliary slots are compared, and the shape of the auxiliary slot of one of the second prototypes with relatively small first-order and second-order electromagnetic forces is determined as the optimized design.

[0016] In one embodiment, after comparing the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots are qualified, and determining the shape of the auxiliary slot of one of the second prototypes whose first-order and second-order electromagnetic forces are relatively small as the optimized design, the method for slotting the stator teeth of the asynchronous motor further includes:

[0017] preparing a third prototype of the asynchronous motor, wherein the stator teeth of the third prototype are provided with the auxiliary slots, and the auxiliary slots of the third prototype have the same shape as the auxiliary slots of the second prototype but different sizes; arranging the auxiliary slots into a plurality of different groups according to the sizes of the auxiliary slots of the third prototype to form a plurality of the third prototypes;

[0018] Obtaining external characteristic data of each of the third prototypes in sequence, and obtaining a peak torque of each of the third prototypes based on the external characteristic data of each of the third prototypes; if a ratio of the peak torque of the third prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the third prototype, and determining whether the first-order and second-order electromagnetic forces of the third prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot of the third prototype is qualified;

[0019] The first-order and second-order electromagnetic forces of all the third prototypes whose auxiliary slots are qualified are compared, and the auxiliary slot of one of the third prototypes whose first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

[0020] In one embodiment, after comparing the first-order and second-order electromagnetic forces of all the third prototypes whose auxiliary slots are qualified, and determining the auxiliary slot of one of the third prototypes whose first-order and second-order electromagnetic forces are relatively small as the optimized design, the slotting method of the stator teeth of the asynchronous motor further includes:

[0021] A fourth prototype of the asynchronous motor is prepared, wherein the auxiliary slots are provided on the stator teeth of the fourth prototype, the auxiliary slots of the fourth prototype having the same shape and size as the auxiliary slots of the third prototype, but having a different depth of the auxiliary slots on the stator teeth along the radial direction of the stator than those of the third prototype; the auxiliary slots are arranged into a plurality of groups having different depths along the radial direction of the stator on the stator teeth to form a plurality of fourth prototypes;

[0022] Obtaining external characteristic data of each of the fourth prototypes in sequence, and obtaining a peak torque of each of the fourth prototypes based on the external characteristic data of each of the fourth prototypes; if a ratio of the peak torque of the fourth prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the fourth prototype, and determining whether the first-order and second-order electromagnetic forces of the fourth prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot of the fourth prototype is qualified;

[0023] The first-order and second-order electromagnetic forces of all the fourth prototypes whose auxiliary slots are qualified are compared, and the auxiliary slot of one of the fourth prototypes whose first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

[0024] In one embodiment, m=70, n=4, and the preset values of the ratio of the peak torque of the second prototype to the peak torque of the first prototype, the ratio of the peak torque of the third prototype to the peak torque of the first prototype, and the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype are all greater than 95%.

[0025] In one embodiment, the auxiliary groove of the second prototype as an optimized design is elliptical in shape.

[0026] In one embodiment, the elliptical size of the auxiliary groove of the third prototype as an optimized design is 1.6-2.0 mm in the major axis and 0.5-0.9 mm in the minor axis.

[0027] In one embodiment, the auxiliary slots of the fourth prototype as an optimized design have a depth of 0.2-0.3 mm on the stator teeth along the radial direction of the stator.

[0028] In a second aspect, the present application provides a slotting structure of an asynchronous motor stator tooth portion, wherein the slotting structure of the asynchronous motor stator tooth portion is opened by any one of the slotting methods for the asynchronous motor stator tooth portion provided in the present application.

[0029] In a third aspect, the present application provides an asynchronous motor, which includes any slotted structure of the stator teeth of the asynchronous motor provided in the present application.

[0030] This application obtains the peak torque of the first prototype of the asynchronous motor and compares the peak torque of the second prototype with the peak torque of the first prototype, so as to ensure that the asynchronous motor always meets the performance requirements during the NVH optimization process; and by obtaining the NVH measured data of the first prototype of the asynchronous motor, and obtaining the first-order and second-order electromagnetic forces of the first motor based on the NVH measured data, and comparing the first-order and second-order electromagnetic forces of the second prototype after obtaining the first-order and second-order electromagnetic forces of the second prototype, the idea of guiding simulation calculation based on objective test results can be adopted to effectively improve the problem that the theoretical order of the coupling electromagnetic force between the stator and rotor is quite different from the actual one and cannot efficiently guide NVH optimization, so as to achieve the purpose of accurately improving the first-order and second-order howling of the asynchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of a method for slotting stator teeth of an asynchronous motor provided in Example 1 of the present application;

[0032] Figure 2 A schematic diagram of the structure of the slotted structure of the stator teeth of an asynchronous motor provided in the second embodiment of the present application;

[0033] Figure 3 Another set of flow charts of the method for slotting the stator teeth of an asynchronous motor provided in the first embodiment of the present application;

[0034] Figure 4 A further flow chart of the method for slotting the stator teeth of an asynchronous motor provided in the first embodiment of the present application;

[0035] Figure 5 A further flowchart of the method for slotting the stator teeth of an asynchronous motor provided in the first embodiment of the present application;

[0036] Figure 6 This is a comparison chart of the first-order effect of the full characteristic output of the asynchronous motor stator tooth slot before and after optimization;

[0037] Figure 7 This is a comparison chart of the second-order effects of the full characteristic output of the NVH test before and after the optimization of the stator tooth slots of the asynchronous motor.

[0038] Reference numerals: 100 , stator core; 110 , stator teeth; 120 , stator slots; 130 , auxiliary slots. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0040] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention.

[0041] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented. Any structural modifications, changes in proportional relationships, or adjustments in size should still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0042] Terms such as "upper," "lower," "left," "right," "center," "longitudinal," "transverse," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification to indicate positions or locations are based on those shown in the accompanying drawings and are intended solely for ease of description. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0043] Example 1

[0044] The first embodiment of the present application provides a method for slotting the stator teeth of an asynchronous motor, such as Figure 1 As shown, the method for slotting the stator teeth of an asynchronous motor includes the following steps:

[0045] S1. Obtaining NVH measured data of a first sample of an asynchronous motor, and obtaining first-order and second-order electromagnetic forces of the first sample based on the NVH measured data of the first sample; wherein the asynchronous motor includes a stator and a rotor, the rotor of the asynchronous motor includes m rotor slots, the number of poles of the magnetic field formed by the rotor is n, the first order is mn order, the second order is m order, and the stator teeth 110 of the first sample are not slotted;

[0046] S2. Obtaining external characteristic data of the first sample, and obtaining a peak torque of the first sample based on the external characteristic data of the first sample;

[0047] S3. Prepare a second prototype of the asynchronous motor, wherein the stator teeth 110 of the second prototype are provided with auxiliary slots 130 ; and arrange the auxiliary slots 130 into a plurality of different groups to form a plurality of second prototypes;

[0048] S4. Obtaining external characteristic data of each second prototype in sequence, and obtaining a peak torque of each second prototype based on the external characteristic data of each second prototype; if the ratio of the peak torque of the second prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the second prototype, and determining whether the first-order and second-order electromagnetic forces of the second prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot 130 of the second prototype is qualified;

[0049] S5. Compare the first-order and second-order electromagnetic forces of all qualified second prototypes of the auxiliary slots 130, and determine as the optimized design the auxiliary slot 130 of the second prototype with relatively small first-order and second-order electromagnetic forces.

[0050] like Figure 1 and Figure 2As shown, in this embodiment, for example, in step S1, the asynchronous motor may include a stator and a rotor, wherein the rotor is rotatably disposed within the stator, the stator may include a stator core 100 and a stator winding wound on the stator core 100, the stator core 100 may be provided with a plurality of stator slots 120 at equal intervals along the circumference, and corresponding stator teeth 110 are formed on the inner circumference of the stator core 100, wherein the stator slots 120 are formed by enclosing two adjacent stator teeth 110. The rotor may include a rotor core and a cage winding, wherein the cage winding is disposed on the rotor core, and the rotor core may be provided with a plurality of rotor slots at equal intervals along the circumference.

[0051] like Figure 1 As shown, during the optimization process of slotting the stator teeth 110 of an asynchronous motor, a first asynchronous motor prototype is first prepared. The stator teeth 110 of the first asynchronous motor prototype are not slotted. Once the first prototype is prepared, an NVH test is performed on the first prototype, and actual NVH data for the first prototype is obtained. Since the electromagnetic force of an asynchronous motor is a pair of interacting forces generated by the coupling of the stator magnetic field and the rotor induced magnetic field, the electromagnetic force at the stator end acts on the stator slots 120, the stator windings, and other locations, and is the primary source of the stator slot 120 order. The electromagnetic force at the rotor end primarily acts on the rotor cage bar ends and the rotor bar slots, and is the primary source of the rotor end order. Therefore, after obtaining the actual NVH data for the first prototype, it can be determined that the primary NVH issues of the asynchronous motor are first-order and second-order whine caused by the rotor. The first order is mn-order, and the second order is m-order, where m is the number of rotor slots and n is the number of poles in the magnetic field formed by the rotor. For example, if m=70 and n=4, the main NVH problem of the first sample is the 66th-order and 70th-order howling problems caused by the rotor.

[0052] On this basis, we can adopt the idea of guiding simulation calculations based on objective test results. According to the NVH measured data of the first prototype, it can be obtained that the speeds corresponding to the first and second order maximum howling points of the rotor are the first speed and the second speed respectively. For example, the first speed corresponding to the 66th order maximum howling point of the aforementioned rotor can be 6380rpm, and the second speed corresponding to the 70th order maximum howling point can be 6098rpm. On this basis, the simulation working conditions can be simplified. Specifically, the electromagnetic force of the asynchronous motor at full load and the third speed can be selected for calculation, where the third speed can be the middle value or average value of the first speed and the second speed, for example, the third speed can be 6200rpm; and the rotor speed, stator current, voltage, etc. required for the simulation can all be built according to the actual test results of the prototype bench to recalculate the electromagnetic force at the maximum howling speed point, that is, obtain the first and second order electromagnetic forces of the first prototype based on the NVH measured data of the first prototype.

[0053] like Figure 1 As shown, in step S2, after the first sample is prepared, an external characteristic test is performed on the first sample to obtain external characteristic data of the first sample. After the external characteristic data of the first sample is obtained, the peak torque of the first sample is obtained based on the data. It is not difficult to see that steps S1 and S2 can be performed sequentially, and the execution order is not limited. That is, step S1 can be performed first and then step S2, or step S2 can be performed first and then step S1. At the same time, steps S1 and S2 can also be performed simultaneously, that is, the NVH measured data and external characteristic data of the first sample are obtained simultaneously.

[0054] like Figure 1 As shown, in step S3, auxiliary slots 130 are opened on the stator teeth 110 of the asynchronous motor stator, thus preparing a second prototype. The second prototype can be prepared in multiple numbers, and the auxiliary slots 130 on the stator teeth 110 of the multiple second prototypes are different from each other.

[0055] like Figure 1 As shown, in step S4, after the second prototype is prepared, an external characteristic test is first performed on the second prototype to obtain the peak torque of the second prototype. The peak torque of the second prototype is then compared with the peak torque of the first prototype. If the ratio of the peak torque of the second prototype to the peak torque of the first prototype is greater than or equal to a preset value, such as 0.97, 0.98, 0.99, etc., it is verified that the provision of the auxiliary slot 130 in the stator tooth portion 110 of the second prototype has a small impact on the peak torque of the asynchronous motor and can meet the performance requirements of the asynchronous motor; then, the second prototype can be further subjected to an NVH test. If the ratio of the peak torque of the second prototype to the peak torque of the first prototype is less than the preset value, it is verified that the provision of the auxiliary slot 130 in the stator tooth portion 110 of the second prototype has a large impact on the peak torque of the asynchronous motor and cannot meet the performance requirements, and the auxiliary slot 130 provided in the stator tooth portion 110 of the second prototype is not adopted, and no further NVH test is required.

[0056] After the second prototype undergoes NVH testing, its measured NVH data is obtained, and its first-order and second-order electromagnetic forces are obtained based on the measured NVH data. The method for obtaining the first-order and second-order electromagnetic forces of the rotor of the second prototype can refer to the method for obtaining the first-order and second-order electromagnetic forces of the rotor of the first prototype. After obtaining the first-order and second-order electromagnetic forces of the second prototype, they are compared with the first-order and second-order electromagnetic forces of the first prototype to determine whether the first-order and second-order electromagnetic forces of the second prototype are less than the first-order and second-order electromagnetic forces of the first prototype. If so, it means that the auxiliary slot 130 opened on the stator tooth portion 110 of the second prototype can effectively improve the first-order and second-order howling problems of the asynchronous motor, that is, the auxiliary slot 130 of the second prototype is verified to be qualified; if not, it means that the auxiliary slot 130 opened on the stator tooth portion 110 of the second prototype fails to effectively improve the first-order and second-order howling problems of the asynchronous motor, and the auxiliary slot 130 of the second prototype is verified to be unqualified.

[0057] like Figure 1 As shown, in step S5, after the second prototypes are subjected to NVH tests and the first-order and second-order electromagnetic forces are obtained, the first-order and second-order electromagnetic forces of all the second prototypes with qualified auxiliary slots 130 are compared, and the auxiliary slot 130 of one of the second prototypes is used as the optimized design. Specifically, a second prototype with relatively small first-order and second-order electromagnetic forces can be selected.

[0058] It can be understood that the present application can ensure that the asynchronous motor always meets the performance requirements during the NVH optimization process by obtaining the peak torque of the first prototype of the asynchronous motor and comparing the peak torque of the second prototype with the peak torque of the first prototype; and by obtaining the NVH measured data of the first prototype of the asynchronous motor, and obtaining the first-order and second-order electromagnetic forces of the first motor based on the NVH measured data, and comparing the first-order and second-order electromagnetic forces of the second prototype after obtaining the first-order and second-order electromagnetic forces of the second prototype, the idea of guiding simulation calculations based on objective test results can be adopted to effectively improve the problem that the theoretical order of the coupling electromagnetic force between the stator and rotor is quite different from the actual one and cannot efficiently guide NVH optimization, so as to achieve the purpose of accurately improving the first-order and second-order howling of the asynchronous motor.

[0059] Specifically, a second prototype of the asynchronous motor is prepared, wherein the stator teeth 110 of the second prototype are provided with auxiliary slots 130; and the auxiliary slots 130 are arranged into a plurality of different groups to form a plurality of second prototypes (i.e., step S3), including the following steps:

[0060] S3′, preparing a second prototype of the asynchronous motor, wherein the stator teeth 110 of the second prototype are provided with auxiliary slots 130; the auxiliary slots 130 are arranged into a plurality of different groups according to the shapes of the auxiliary slots 130 to form a plurality of second prototypes;

[0061] Comparing the first-order and second-order electromagnetic forces of all qualified second prototypes of the auxiliary slot 130, and determining the auxiliary slot 130 of the second prototype with relatively small first-order and second-order electromagnetic forces as the optimized design (i.e., step S5), includes the following steps:

[0062] S5′, comparing the first-order and second-order electromagnetic forces of all qualified second prototypes of the auxiliary slot 130, and determining the shape of the auxiliary slot 130 of one of the second prototypes with relatively small first-order and second-order electromagnetic forces as the optimized design.

[0063] like Figure 3 As shown, in this embodiment, for example, in step S3′, the auxiliary slots 130 of the plurality of second prototypes may have different shapes, such as circular, elliptical, rectangular, etc. In step S5′, after obtaining the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots 130 have been verified as qualified, the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots 130 have been qualified are compared, and the auxiliary slot 130 of one of the second prototypes is selected as the optimized design. At this time, the content to be determined may be the shape of the auxiliary slot 130.

[0064] It is understandable that, in this embodiment, by setting the auxiliary slot 130 of the second prototype to several different shapes, the shape of the auxiliary slot 130 as the optimized design can be determined to achieve the purpose of accurately slotting the stator teeth 110 of the asynchronous motor.

[0065] More specifically, after comparing the first-order and second-order electromagnetic forces of all second prototypes with qualified auxiliary slots 130 and determining the shape of the auxiliary slot 130 of one second prototype with relatively small first-order and second-order electromagnetic forces as the optimized design (i.e., after step S5′), the method for slotting the stator teeth of an asynchronous motor further includes the following steps:

[0066] S6. Prepare a third prototype of the asynchronous motor, wherein the stator teeth 110 of the third prototype are provided with auxiliary slots 130 , and the auxiliary slots 130 of the third prototype have the same shape as the auxiliary slots 130 of the second prototype but different sizes; the auxiliary slots 130 are arranged into a plurality of different groups according to the sizes of the auxiliary slots 130 of the third prototype, to form a plurality of third prototypes;

[0067] S7. Obtaining external characteristic data of each third prototype in sequence, and obtaining a peak torque of each third prototype based on the external characteristic data of each third prototype; if the ratio of the peak torque of the third prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the third prototype, and determining whether the first-order and second-order electromagnetic forces of the third prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot 130 of the third prototype is qualified;

[0068] S8. Compare the first-order and second-order electromagnetic forces of all qualified third prototypes of the auxiliary slot 130, and determine the auxiliary slot 130 of the third prototype with relatively small first-order and second-order electromagnetic forces as the optimized design.

[0069] like Figure 4 As shown, in this embodiment, for example, in step S6, the preparation method of the third prototype is the same as that of the second prototype; at the same time, the shape of the auxiliary groove 130 of the third prototype is the shape of the auxiliary groove 130 determined as the optimized design for the second prototype. There are also multiple third prototypes, and the dimensions of the auxiliary grooves 130 of the multiple third prototypes are different.

[0070] like Figure 4 As shown, in step S7, after the third prototype is prepared, an external characteristic test is first performed on the third prototype to obtain the peak torque of the third prototype. Similarly, the peak torque of the third prototype is then compared with the peak torque of the first prototype. If the ratio of the peak torque of the third prototype to the peak torque of the first prototype is greater than or equal to a preset value, it is verified that the provision of the auxiliary slot 130 in the stator tooth portion 110 of the third prototype has little impact on the peak torque of the asynchronous motor and can meet the performance requirements of the asynchronous motor; and then, the third prototype can be further subjected to an NVH test. Otherwise, the auxiliary slot 130 provided in the stator tooth portion 110 of the third prototype is not adopted. In this embodiment, the preset value of the ratio of the peak torque of the third prototype to the peak torque of the first prototype can be equal to the preset value of the ratio of the peak torque of the second prototype to the peak torque of the first prototype.

[0071] Similarly, after the third prototype undergoes NVH testing, its measured NVH data is obtained, and its first-order and second-order electromagnetic forces are obtained based on the measured NVH data. The first-order and second-order electromagnetic forces of the third prototype are then compared with the first-order and second-order electromagnetic forces of the first prototype to determine whether the first-order and second-order electromagnetic forces of the third prototype are smaller than the first-order and second-order electromagnetic forces of the first prototype. If so, it indicates that the auxiliary slots 130 provided on the stator teeth 110 of the third prototype can effectively improve the first-order and second-order whistling problems of the asynchronous motor, that is, the auxiliary slots 130 of the third prototype are verified to be qualified; otherwise, the auxiliary slots 130 of the third prototype are verified to be unqualified.

[0072] like Figure 4 As shown, in step S8, after obtaining the first-order and second-order electromagnetic forces of all the qualified third prototypes of the auxiliary slot 130, the first-order and second-order electromagnetic forces of all the qualified third prototypes of the auxiliary slot 130 are compared, and the auxiliary slot 130 of one of the third prototypes is selected as the optimized design. Further content to be determined at this time may be the size of the auxiliary slot 130. Similarly, a third prototype with relatively small first-order and second-order electromagnetic forces may be selected.

[0073] It can be understood that, in this embodiment, by setting the several auxiliary slots 130 of the third prototype to have the same shape but different sizes, the size of the auxiliary slot 130 as the optimized design can be further determined to further improve the accuracy of slotting on the stator tooth portion 110 of the asynchronous motor.

[0074] More specifically, after comparing the first-order and second-order electromagnetic forces of all qualified third prototypes of the auxiliary slots 130 and determining the auxiliary slot 130 of one third prototype with relatively small first-order and second-order electromagnetic forces as the optimized design (i.e., after step S8), the method for slotting the stator teeth of the asynchronous motor further includes the following steps:

[0075] S9. Prepare a fourth prototype of the asynchronous motor, wherein the stator teeth 110 of the fourth prototype are provided with auxiliary slots 130. The auxiliary slots 130 of the fourth prototype have the same shape and size as the auxiliary slots 130 of the third prototype, but the depth of the auxiliary slots 130 on the stator teeth 110 along the radial direction of the stator is different from that of the third prototype. The auxiliary slots 130 are arranged into a plurality of groups having different depths along the radial direction of the stator on the stator teeth 110 to form a plurality of fourth prototypes.

[0076] S10, sequentially obtaining external characteristic data of each fourth prototype, and obtaining a peak torque of each fourth prototype based on the external characteristic data of each fourth prototype; if the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining first-order and second-order electromagnetic forces of the fourth prototype, and determining whether the first-order and second-order electromagnetic forces of the fourth prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot 130 of the fourth prototype is qualified;

[0077] S11 , comparing the first-order and second-order electromagnetic forces of all qualified fourth prototypes of the auxiliary slot 130 , and determining the auxiliary slot 130 of the fourth prototype with relatively small first-order and second-order electromagnetic forces as the optimized design.

[0078] like Figure 5 As shown, in this embodiment, for example, in step S9, the fourth prototype is prepared in a similar manner; the shape and size of the auxiliary slot 130 of the fourth prototype are the shape of the auxiliary slot 130 determined as the optimized design for the second prototype and the size of the auxiliary slot 130 determined as the optimized design for the third prototype. The fourth prototype is also provided in multiple configurations, and the auxiliary slots 130 of the multiple fourth prototypes have different depths along the radial direction of the stator on the stator tooth 110, that is, the slot depths are different.

[0079] like Figure 5 As shown, in step S10, after the fourth prototype is prepared, an external characteristic test is performed on the fourth prototype to obtain the peak torque of the fourth prototype. The peak torque of the fourth prototype is then compared with the peak torque of the first prototype. If the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype is greater than or equal to a preset value, it is verified that the inclusion of the auxiliary slots 130 in the stator teeth 110 of the fourth prototype has a minimal impact on the peak torque of the asynchronous motor and can meet the performance requirements of the asynchronous motor. The fourth prototype is then further subjected to an NVH test. Otherwise, the inclusion of the auxiliary slots 130 in the stator teeth 110 of the fourth prototype is not adopted. In this embodiment, the preset value for the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype can be equal to the preset value for the ratio of the peak torque of the second prototype to the peak torque of the first prototype and the preset value for the ratio of the peak torque of the third prototype to the peak torque of the first prototype.

[0080] Similarly, after the fourth prototype undergoes NVH testing, its measured NVH data is obtained, and its first-order and second-order electromagnetic forces are obtained based on the measured NVH data. The first-order and second-order electromagnetic forces of the fourth prototype are then compared with the first-order and second-order electromagnetic forces of the first prototype to determine whether the first-order and second-order electromagnetic forces of the fourth prototype are less than the first-order and second-order electromagnetic forces of the first prototype. If so, it indicates that the auxiliary slots 130 provided on the stator teeth 110 of the fourth prototype can effectively improve the first-order and second-order whistling problems of the asynchronous motor, that is, the auxiliary slots 130 of the fourth prototype are verified to be qualified; otherwise, the auxiliary slots 130 of the fourth prototype are verified to be unqualified.

[0081] like Figure 5 As shown, in step S11, after obtaining the first-order and second-order electromagnetic forces of all fourth prototypes whose auxiliary slots 130 are verified as qualified, the first-order and second-order electromagnetic forces of all fourth prototypes whose auxiliary slots 130 are qualified are compared, and the auxiliary slot 130 of one of the fourth prototypes is selected as the optimized design. Further determination may be made at this time regarding the slot depth of the auxiliary slot 130, i.e., the depth of the auxiliary slot 130 on the stator tooth 110 along the radial direction of the stator. Similarly, a fourth prototype with relatively small first-order and second-order electromagnetic forces may be selected.

[0082] It can be understood that, in this embodiment, by setting the several auxiliary slots 130 of the fourth prototype to have the same shape and size, but different depths on the stator tooth portion 110 along the radial direction of the stator, the depth of the auxiliary slot 130 along the radial direction of the stator on the stator tooth portion 110 as the optimized design can be further determined, so as to further improve the accuracy of slotting on the stator tooth portion 110 of the asynchronous motor.

[0083] More specifically, m=70, n=4, and the preset values of the ratio of the peak torque of the second prototype to the peak torque of the first prototype, the ratio of the peak torque of the third prototype to the peak torque of the first prototype, and the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype are all greater than 95%.

[0084] like Figure 3-5 As shown, in this embodiment, for example, m can be 70, n can be 4, and the primary NVH issue for the first prototype is the 66th- and 70th-order whistling caused by the rotor. In steps S1, S4, S7, and S10, the 66th- and 70th-order electromagnetic forces of the first, second, third, and fourth prototypes are obtained, respectively. In steps S4, S7, and S10, the preset value for the ratio of the peak torque of the second, third, and fourth prototypes to the peak torque of the first prototype can all be greater than 95%.

[0085] It can be understood that this embodiment ensures that the performance of the asynchronous motor under specified parameters can meet the use requirements after the optimized design of the slots in the stator teeth 110 is performed by reasonably setting the data relationship between the number of slots in the rotor and the number of poles in the magnetic field formed by the rotor and the preset value of the ratio of the peak torque of the second prototype, the third prototype and the fourth prototype to the peak torque of the first prototype.

[0086] More specifically, the auxiliary groove 130 of the second prototype as the optimized design is in an elliptical shape.

[0087] like Figure 2 As shown, in this embodiment, for example, the shape of the auxiliary slot 130 of the second prototype determined according to steps S1-S5 can be an ellipse. In this case, the minor axis direction of the auxiliary slot 130 can be the radial direction of the stator, and the length direction of the auxiliary slot 130 can be the tangential direction of the stator. Furthermore, the auxiliary slots 130 can be symmetrically arranged on the stator teeth 110.

[0088] More specifically, the dimensions of the elliptical auxiliary groove 130 of the third prototype as the optimized design are 1.6-2.0 mm in the major axis and 0.5-0.9 mm in the minor axis.

[0089] like Figure 2 As shown, in this embodiment, for example, the dimensions of the auxiliary groove 130 of the third prototype determined according to steps S6-S8 can be 1.6-2.0 mm in the major axis and 0.5-0.9 mm in the minor axis, for example, 1.79 mm in the major axis and 0.7 mm in the minor axis. Of course, in some embodiments, the major axis and the minor axis can also be other values.

[0090] More specifically, the auxiliary slots 130 of the fourth prototype as the optimized design have a depth of 0.2-0.3 mm on the stator teeth 110 along the radial direction of the stator.

[0091] like Figure 2 As shown, in this embodiment, for example, the groove depth of the auxiliary groove 130 of the fourth prototype determined according to steps S9-S11 may be 0.2-0.3 mm, for example 0.25 mm. Of course, in some embodiments, the groove depth may also be other values.

[0092] like Figure 6 and Figure 7As shown, it has been verified that when the stator teeth 110 of an asynchronous motor with 70 rotor slots and 4 magnetic field poles are provided with an auxiliary slot 130 having an elliptical shape, a major axis of 1.79 mm, a minor axis of 0.7 mm, and a depth of 0.25 mm along the radial direction of the stator on the stator teeth 110, the 66th order noise can be reduced by 3-18 dB and the 70th order noise can be reduced by 3-15 dB under 100% external characteristic output conditions of the asynchronous motor, and the order noise optimization effect is obvious. Figure 6 and attached Figure 7 In the figure, the dotted line represents the data after the asynchronous motor is slotted, and the solid line represents the data without slotting.

[0093] Example 2

[0094] A second embodiment of the present application provides a slotting structure of a stator tooth portion 110 of an asynchronous motor. The slotting structure of the stator tooth portion 110 of the asynchronous motor is opened by any slotting method of a stator tooth portion of an asynchronous motor provided in the present application.

[0095] Example 3

[0096] A third embodiment of the present application provides an asynchronous motor, which includes any slotted structure of the stator teeth 110 of the asynchronous motor provided in the present application.

[0097] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for slotting stator teeth of an asynchronous motor, characterized in that: The slotting method of the stator teeth of the asynchronous motor comprises: Acquiring NVH measured data of a first prototype of an asynchronous motor, and acquiring first-order and second-order electromagnetic forces of the first prototype based on the NVH measured data of the first prototype; wherein the asynchronous motor comprises a stator and a rotor, the rotor of the asynchronous motor comprises m rotor slots, the number of poles of the magnetic field formed by the rotor is n poles, the first order is mn order, the second order is m order, and the stator teeth (110) of the first prototype are not slotted; Acquiring external characteristic data of the first prototype, and acquiring a peak torque of the first prototype based on the external characteristic data of the first prototype; A second prototype of the asynchronous motor is prepared, wherein the stator teeth (110) of the second prototype are provided with auxiliary slots (130); and the auxiliary slots (130) are arranged into a plurality of different groups to form a plurality of the second prototypes; Obtaining the external characteristic data of each second prototype in sequence, and obtaining the peak torque of each second prototype based on the external characteristic data of each second prototype; if the ratio of the peak torque of the second prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the second prototype, and judging whether the first-order and second-order electromagnetic forces of the second prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot (130) of the second prototype is qualified; The first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots (130) are qualified are compared, and the auxiliary slot (130) of the second prototype in which both the first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

2. The method for slotting the stator teeth of an asynchronous motor according to claim 1, characterized in that: A second prototype of the asynchronous motor is prepared, wherein the stator teeth (110) of the second prototype are provided with auxiliary slots (130); and the auxiliary slots (130) are arranged into a plurality of different groups to form a plurality of the second prototypes, comprising: preparing a second prototype of the asynchronous motor, wherein the stator teeth (110) of the second prototype are provided with the auxiliary slots (130); arranging the auxiliary slots (130) into a plurality of different groups according to the shapes of the auxiliary slots (130) to form a plurality of the second prototypes; Comparing the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots (130) are qualified, and determining the auxiliary slot (130) of the second prototype whose first-order and second-order electromagnetic forces are both relatively small as an optimized design, comprising: The first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots (130) are qualified are compared, and the shape of the auxiliary slot (130) of one of the second prototypes whose first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

3. The method for slotting the stator teeth of an asynchronous motor according to claim 2, characterized in that: After comparing the first-order and second-order electromagnetic forces of all the second prototypes whose auxiliary slots (130) are qualified, and determining the shape of the auxiliary slot (130) of one of the second prototypes whose first-order and second-order electromagnetic forces are relatively small as an optimized design, the slotting method of the stator teeth of the asynchronous motor further includes: A third prototype of the asynchronous motor is prepared, wherein the stator teeth (110) of the third prototype are provided with the auxiliary slots (130), and the auxiliary slots (130) of the third prototype are the same in shape as the auxiliary slots (130) of the second prototype but different in size; the auxiliary slots (130) are arranged into a plurality of different groups according to the size of the auxiliary slots (130) of the third prototype to form a plurality of the third prototypes; Obtaining the external characteristic data of each of the third prototypes in sequence, and obtaining the peak torque of each of the third prototypes according to the external characteristic data of each of the third prototypes; if the ratio of the peak torque of the third prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the third prototype, and judging whether the first-order and second-order electromagnetic forces of the third prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot (130) of the third prototype is qualified; The first-order and second-order electromagnetic forces of all the third prototypes whose auxiliary slots (130) are qualified are compared, and the auxiliary slot (130) of the third prototype in which both the first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

4. The method for slotting the stator teeth of an asynchronous motor according to claim 3, characterized in that: After comparing the first-order and second-order electromagnetic forces of all the third prototypes whose auxiliary slots (130) are qualified, and determining the auxiliary slot (130) of the third prototype whose first-order and second-order electromagnetic forces are both relatively small as the optimized design, the slotting method of the stator teeth of the asynchronous motor further includes: A fourth prototype of the asynchronous motor is prepared, wherein the auxiliary slot (130) is provided on the stator tooth portion (110) of the fourth prototype, the auxiliary slot (130) of the fourth prototype is identical in shape and size to the auxiliary slot (130) of the third prototype, and the depth of the auxiliary slot (130) of the fourth prototype on the stator tooth portion (110) along the radial direction of the stator is different from that of the third prototype; the auxiliary slots (130) are arranged into a plurality of different groups according to the depth of the auxiliary slot (130) on the stator tooth portion (110) along the radial direction of the stator, so as to form a plurality of the fourth prototypes; Obtaining the external characteristic data of each of the fourth prototypes in sequence, and obtaining the peak torque of each of the fourth prototypes according to the external characteristic data of each of the fourth prototypes; if the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype is greater than or equal to a preset value, obtaining the first-order and second-order electromagnetic forces of the fourth prototype, and judging whether the first-order and second-order electromagnetic forces of the fourth prototype are less than the first-order and second-order electromagnetic forces of the first prototype; if so, verifying that the auxiliary slot (130) of the fourth prototype is qualified; The first-order and second-order electromagnetic forces of all the fourth prototypes whose auxiliary slots (130) are qualified are compared, and the auxiliary slot (130) of the fourth prototype in which both the first-order and second-order electromagnetic forces are relatively small is determined as the optimized design.

5. The method for slotting the stator teeth of an asynchronous motor according to claim 4, characterized in that: m=70, n=4, and preset values of the ratio of the peak torque of the second prototype to the peak torque of the first prototype, the ratio of the peak torque of the third prototype to the peak torque of the first prototype, and the ratio of the peak torque of the fourth prototype to the peak torque of the first prototype are all greater than 95%.

6. The method for slotting the stator teeth of an asynchronous motor according to claim 5, characterized in that: The auxiliary groove (130) of the second prototype as an optimized design is in an elliptical shape.

7. The method for slotting the stator teeth of an asynchronous motor according to claim 6, characterized in that: The elliptical dimensions of the auxiliary groove (130) of the third prototype as an optimized design are 1.6-2.0 mm in the major axis and 0.5-0.9 mm in the minor axis.

8. The method for slotting the stator teeth of an asynchronous motor according to claim 7, characterized in that: As the fourth prototype with an optimized design, the depth of the auxiliary slot (130) on the stator tooth portion (110) along the radial direction of the stator is 0.2-0.3 mm.

9. A slotted structure of an asynchronous motor stator tooth, characterized in that: The slotting structure of the stator teeth of the asynchronous motor is opened by the slotting method of the stator teeth of the asynchronous motor according to any one of claims 1 to 8.

10. An asynchronous motor, characterized in that: The asynchronous motor comprises the slotted structure of the stator teeth of the asynchronous motor according to claim 9.

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