A slotting method, slotting structure and asynchronous motor for a stator tooth of an asynchronous motor

Abstract

This application relates to a slotting method, slotting structure, and asynchronous motor for the stator teeth. The method includes: acquiring NVH measurement data of a first prototype, and acquiring the first and second order electromagnetic forces of the first prototype based on the NVH measurement data; acquiring the peak torque of the first prototype; preparing a second prototype; acquiring the peak torque of each second prototype sequentially; if the ratio is greater than or equal to a preset value, acquiring the first and second order electromagnetic forces of the second prototype and determining whether they are less than those of the first prototype; if so, verifying that it is qualified; comparing all second prototypes with qualified auxiliary slots, and determining one as the optimized design. This application can effectively improve the problem of large differences between the theoretical order of the stator and rotor coupling electromagnetic forces and the actual order, which makes it difficult to efficiently guide NVH optimization, by using objective test results to guide simulation calculations, thereby achieving the goal of accurately improving the first and second order howling of the asynchronous motor.

Description

Technical Field

[0001] This application relates to the technical field of asynchronous motors, and particularly to a slotting method, a slotting structure for the stator teeth of an asynchronous motor, and 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 symmetric three-phase 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, causing 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 speed difference (n1 - n) between the rotating magnetic field speed n1 generated after inputting a symmetric three-phase current with a fixed frequency f1 into the stator and the magnetic field speed n 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 working state of the asynchronous motor at any time can be directly judged, mainly including the generator operation state (S < 0), the motor operation 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 input. The main characteristic of the rotor of an asynchronous motor is the cage structure, which is cast by a die-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, and further a rotating magnetic field is generated by the rotor itself. The stator magnetic field and the rotor magnetic field interact with each other 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 the stator order; the rotor end mainly acts on the rotor cage bar ends and the rotor bar slots, which is the source of the rotor end order. 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 radial direction of the rotor cross-section radius, and a tangential electromagnetic force.

[0004] Radial electromagnetic force is a key adjustment point when asynchronous motors exhibit magnetic order issues. Reducing the radial electromagnetic force can effectively improve the NVH performance of asynchronous motors. Adjusting the radial electromagnetic force can include slotting the stator teeth. However, when calculating the corresponding electromagnetic force of an asynchronous motor, since the rotor lacks a permanent magnet magnetic field, issues such as slip must be considered. The theoretical order of the coupling electromagnetic force between the stator and rotor differs significantly from the actual order, making it inefficient for guiding NVH optimization; in other words, it cannot provide a reference for slotting the stator teeth. Summary of the Invention

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

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

[0007] Obtain NVH measured data of the first prototype of the asynchronous motor, and obtain the first 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 magnetic field poles formed by the rotor is n poles, the first order is mn order, the second order is m order, and the stator teeth of the first prototype are not slotted.

[0008] Obtain the external characteristic data of the first prototype, and obtain the peak torque of the first prototype based on the external characteristic data of the first prototype;

[0009] A second prototype of the asynchronous motor is prepared, wherein the stator teeth of the second prototype are provided with auxiliary slots; and the auxiliary slots are set into several different groups to form several second prototypes;

[0010] The external characteristic data of each second prototype is acquired sequentially, and the peak torque of each second prototype is obtained 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, the first-order and second-order electromagnetic forces of the second prototype are acquired, and it is determined 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, the auxiliary groove of the second prototype is verified to be qualified.

[0011] Compare the first-order and second-order electromagnetic forces of all qualified second prototypes of the auxiliary slot, and determine the auxiliary slot of the second prototype with relatively small first-order and second-order electromagnetic forces as the optimized design.

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

[0013] A second prototype of the asynchronous motor is prepared, wherein the stator teeth of the second prototype are provided with the auxiliary slots; the auxiliary slots are set into several groups that are different from each other according to the shape of the auxiliary slots, so as to form several second prototypes;

[0014] Compare the first-order and second-order electromagnetic forces of all qualified second prototypes of the auxiliary slot, and determine the auxiliary slot of the second prototype with relatively small first-order and second-order electromagnetic forces as the optimized design, including:

[0015] By comparing the first and second order electromagnetic forces of all qualified second prototypes of the auxiliary groove, the shape of the auxiliary groove of the second prototype in which both the first and second order electromagnetic forces are relatively small is determined as an optimized design.

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

[0017] A third prototype of the asynchronous motor is prepared, 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 but different size from the auxiliary slots of the second prototype; the auxiliary slots are set into several groups that are different from each other according to the size of the auxiliary slots of the third prototype, so as to form several third prototypes.

[0018] The external characteristic data of each of the third prototypes are acquired sequentially, and the peak torque of each third prototype is obtained based on the external characteristic data. 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, the first-order and second-order electromagnetic forces of the third prototype are acquired, and it is determined 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, the auxiliary groove of the third prototype is verified as qualified.

[0019] By comparing the first and second order electromagnetic forces of all qualified third prototypes of the auxiliary slot, the auxiliary slot of the third prototype in which both the first and second order electromagnetic forces are relatively small is selected as the optimized design.

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

[0021] A fourth prototype of the asynchronous motor is prepared, wherein the auxiliary slot is provided on the stator teeth of the fourth prototype, the auxiliary slot of the fourth prototype has the same shape and size as the auxiliary slot of the third prototype, and the depth of the auxiliary slot of the fourth prototype along the radial direction of the stator on the stator teeth is different from that of the third prototype; the auxiliary slots are set into several groups of different depths along the radial direction of the stator on the stator teeth to form several fourth prototypes;

[0022] The external characteristic data of each of the fourth prototypes are acquired sequentially, and the peak torque of each fourth prototype is obtained 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, the first-order and second-order electromagnetic forces of the fourth prototype are acquired, and it is determined 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, the auxiliary groove of the fourth prototype is verified as qualified.

[0023] By comparing the first and second order electromagnetic forces of all qualified fourth prototypes of the auxiliary slot, the auxiliary slot of the fourth prototype in which both the first and second order electromagnetic forces are relatively small is selected as the optimized design.

[0024] In one embodiment, m = 70, n = 4, and the preset values ​​for 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, which is an optimized design, is elliptical in shape.

[0026] In one embodiment, the auxiliary groove of the third prototype, which is an optimized design, has an elliptical shape with a major axis of 1.6-2.0 mm and a minor axis of 0.5-0.9 mm.

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

[0028] Secondly, this application provides a slotted structure for the stator teeth of an asynchronous motor, wherein the slotted structure for the stator teeth of the asynchronous motor is formed by any of the slotting methods for the stator teeth of an asynchronous motor provided in this application.

[0029] Thirdly, this application provides an asynchronous motor, which includes any of the slotted structures of the stator teeth of the asynchronous motor provided in this application.

[0030] This application obtains the peak torque of the first prototype of the asynchronous motor and compares it with the peak torque of the second prototype, ensuring that the asynchronous motor always meets performance requirements during NVH optimization. Furthermore, by obtaining the NVH measured data of the first prototype and acquiring its first and second order electromagnetic forces, and then comparing these forces with those of the second prototype, the application adopts an approach that uses objective test results to guide simulation calculations. This effectively addresses the problem of significant discrepancies between theoretical and actual values ​​in the order of the stator and rotor coupling electromagnetic forces, which hinders efficient NVH optimization. Ultimately, this aims to accurately improve the first and second order howling of the asynchronous motor. Attached Figure Description

[0031] Figure 1 A flowchart of the grooving method for the stator teeth of an asynchronous motor provided in Embodiment 1 of this application;

[0032] Figure 2 This is a schematic diagram of the slotted structure of the stator teeth of the asynchronous motor provided in Embodiment 2 of this application;

[0033] Figure 3 This is another set of flowcharts for the method of slotting the stator teeth of an asynchronous motor provided in Embodiment 1 of this application;

[0034] Figure 4 A further flowchart of the grooving method for the stator teeth of an asynchronous motor provided in Embodiment 1 of this application;

[0035] Figure 5 A further flowchart of the slotting method for the stator teeth of an asynchronous motor provided in Embodiment 1 of this application;

[0036] Figure 6 A comparison of the first-order effect of full-scale characteristic output in NVH tests before and after optimization of stator tooth slotting for asynchronous motors;

[0037] Figure 7 A comparison chart showing the second-order effect of full-characteristic output in NVH tests before and after slotting optimization of the stator teeth of an asynchronous motor.

[0038] Reference numerals: 100, stator core; 110, stator teeth; 120, stator slot; 130, auxiliary slot. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention.

[0041] The structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0042] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "lateral," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are only for the purpose of simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] Example 1

[0044] Embodiment 1 of this 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. Obtain the NVH measured data of the first prototype of the asynchronous motor, and obtain the first 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 magnetic field poles 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.

[0046] S2. Obtain the external characteristic data of the first prototype, and obtain the peak torque of the first prototype based on the external characteristic data of the first prototype;

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

[0048] S4. Sequentially acquire the external characteristic data of each second prototype, and acquire 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, acquire the first-order and second-order electromagnetic forces of the second prototype, and 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, verify that the auxiliary slot 130 of the second prototype is qualified.

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

[0050] like Figure 1 and Figure 2As shown in this embodiment, by way of 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 stator windings wound on the stator core 100. The stator core 100 may have a plurality of stator slots 120 evenly spaced along the circumference, and corresponding stator teeth 110 are formed on the inner circumferential side of the stator core 100. The stator slots 120 are formed by two adjacent stator teeth 110. The rotor may include a rotor core and a cage winding, the cage winding being disposed on the rotor core. The rotor core may have a plurality of rotor slots evenly spaced along the circumference.

[0051] like Figure 1 As shown, in the optimization process of slotting the stator teeth 110 of the asynchronous motor, the first prototype of the asynchronous motor was first prepared, and the stator teeth 110 of the first prototype of the asynchronous motor were not slotted. When the first prototype was completed, NVH tests were carried out on the first prototype, and the measured NVH data of the first prototype were obtained. Since the electromagnetic force of the asynchronous motor is a pair of interaction 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, stator windings, etc., and is the main source of the order of the stator slots 120; the electromagnetic force at the rotor end mainly acts on the rotor cage guide bar ends and rotor guide bar slots, and is the source of the rotor end order. Therefore, after obtaining the measured NVH data of the first prototype, it can be determined that the main NVH problem of the asynchronous motor is the first-order and second-order howling problem caused by the rotor, where 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 of the magnetic field formed by the rotor. For example, when m=70 and n=4, the main NVH problem of the first prototype is the 66th and 70th order howling caused by the rotor.

[0052] Based on this, an approach can be adopted that uses objective test results to guide simulation calculations. According to the NVH measurement data of the first prototype, the speeds corresponding to the first and second order maximum squealing points of the rotor can be obtained as the first speed and the second speed, respectively. For example, the first speed corresponding to the 66th order maximum squealing point of the rotor can be 6380 rpm, and the second speed corresponding to the 70th order maximum squealing point can be 6098 rpm. Based on this, the simulation conditions can be simplified. Specifically, the electromagnetic force at the third speed of the asynchronous motor under full load can be selected for calculation. The third speed can be the midpoint or average of the first and second speeds, for example, 6200 rpm. The rotor speed, stator current, voltage, etc., required for simulation can all be modeled according to the actual test results of the prototype bench to recalculate the electromagnetic force at the maximum squealing speed point. That is, the first and second order electromagnetic forces of the first prototype can be obtained based on the NVH measurement data of the first prototype.

[0053] like Figure 1 As shown, in step S2, when the first prototype is completed, an external characteristic test is performed on the first prototype to obtain its external characteristic data; and after obtaining the external characteristic data of the first prototype, the peak torque of the first prototype is obtained based on it. It is easy to see that steps S1 and S2 can be executed sequentially, and the execution order is not limited, that is, step S1 can be executed first and then step S2, or step S2 can be executed first and then step S1; at the same time, steps S1 and S2 can also be executed synchronously, that is, the NVH measured data and external characteristic data of the first prototype are obtained simultaneously.

[0054] like Figure 1 As shown, in step S3, auxiliary slots 130 are formed on the stator teeth 110 of the asynchronous motor stator, thus obtaining the second prototype. Several second prototypes can be prepared, and the auxiliary slots 130 on the stator teeth 110 of the several second prototypes are all different.

[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 its peak torque. Then, the peak torque of the second prototype is compared with that of the first prototype. If the ratio of the peak torque of the second prototype to that of the first prototype is greater than or equal to a preset value, such as 0.97, 0.98, or 0.99, it is verified that the auxiliary slot 130 in the stator gear 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. Subsequently, an NVH test can be further performed on the second prototype. If the ratio of the peak torque of the second prototype to that of the first prototype is less than the preset value, it is verified that the auxiliary slot 130 in the stator gear 110 of the second prototype has a large impact on the peak torque of the asynchronous motor and cannot meet the performance requirements. Therefore, the auxiliary slot 130 in the stator gear 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 acquired, and the first and second order electromagnetic forces are obtained based on this data. The method for acquiring the first and second order electromagnetic forces of the rotor in the second prototype can refer to the method used for acquiring the first and second order electromagnetic forces of the rotor in the first prototype. After acquiring the first and second order electromagnetic forces of the second prototype, they are compared with those of the first prototype to determine whether the first and second order electromagnetic forces of the second prototype are less than those of the first prototype. If yes, it means that the auxiliary slot 130 opened on the stator tooth section 110 of the second prototype can effectively improve the first and second order squealing problem of the asynchronous motor, that is, the auxiliary slot 130 of the second prototype is verified to be qualified; if no, it means that the auxiliary slot 130 opened on the stator tooth section 110 of the second prototype has failed to effectively improve the first and second order squealing problem of the asynchronous motor, that is, the auxiliary slot 130 of the second prototype is verified to be unqualified.

[0057] like Figure 1 As shown, in step S5, after all the second prototypes have undergone NVH testing and the first and second order electromagnetic forces have been obtained, the first 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 selected as the optimized design. Specifically, the second prototype with relatively small first and second order electromagnetic forces can be selected.

[0058] Understandably, this application, by obtaining the peak torque of the first prototype of the asynchronous motor and comparing it with the peak torque of the second prototype, can ensure that the asynchronous motor always meets performance requirements during NVH optimization. Furthermore, by obtaining the NVH measured data of the first prototype of the asynchronous motor and obtaining the first and second order electromagnetic forces of the first motor based on the measured data, and then comparing the first and second order electromagnetic forces of the second prototype after obtaining them, the approach of using objective test results to guide simulation calculations can effectively improve the problem that the theoretical order of the stator and rotor coupling electromagnetic forces differs greatly from reality and cannot efficiently guide NVH optimization, thereby achieving the goal of accurately improving the first and second order howling of the asynchronous motor.

[0059] Specifically, a second prototype of an 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 set into several different groups to form several second prototypes (i.e., step S3), including the following steps:

[0060] S3′, Prepare a second prototype of the asynchronous motor, wherein the stator teeth 110 of the second prototype is provided with auxiliary slots 130; according to the shape of the auxiliary slots 130, set the auxiliary slots 130 into several groups that are different from each other to form several second prototypes;

[0061] Compare the first and second order electromagnetic forces of all qualified second prototypes in auxiliary tank 130, and determine the auxiliary tank 130 of one second prototype with relatively small first and second order electromagnetic forces as the optimized design (i.e., step S5), including the following steps:

[0062] S5′, compare the first and second order electromagnetic forces of all qualified second prototypes of auxiliary groove 130, and determine the shape of the auxiliary groove 130 of one of the second prototypes with relatively small first and second order electromagnetic forces as the optimization design.

[0063] like Figure 3 As shown in this embodiment, by way of example, in step S3′, the auxiliary slots 130 of several second prototypes can have different shapes, such as circular, elliptical, or rectangular. In step S5′, after all second prototypes whose auxiliary slots 130 are verified as qualified have obtained their first and second order electromagnetic forces, the first and second order electromagnetic forces of all second prototypes whose auxiliary slots 130 are qualified are compared, and the auxiliary slot 130 of one of the second prototypes is selected as the optimized design. At this time, the determined content can be the shape of the auxiliary slot 130.

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

[0065] More specifically, after comparing the first 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 and second order electromagnetic forces as an optimized design (i.e., after step S5′), the grooving method for the stator teeth of the asynchronous motor further includes the following steps:

[0066] S6. Prepare a third prototype of an asynchronous motor, wherein the stator teeth 110 of the third prototype is provided with an auxiliary slot 130, and the auxiliary slot 130 of the third prototype has the same shape but different size as the auxiliary slot 130 of the second prototype; according to the size of the auxiliary slot 130 of the third prototype, set the auxiliary slot 130 into several groups that are different from each other to form several third prototypes.

[0067] S7. Sequentially acquire the external characteristic data of each third prototype, and acquire the 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, acquire the first and second order electromagnetic forces of the third prototype, and determine whether the first and second order electromagnetic forces of the third prototype are less than the first and second order electromagnetic forces of the first prototype; if so, verify that the auxiliary slot 130 of the third prototype is qualified.

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

[0069] like Figure 4 As shown in this embodiment, by way of 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 an optimized design in the second prototype. Furthermore, several third prototypes are also provided, and the dimensions of the auxiliary groove 130 of each of the several third prototypes are different.

[0070] like Figure 4 As shown, in step S7, after the third prototype is prepared, an external characteristic test is performed on the third prototype to obtain its peak torque. 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 auxiliary slot 130 opened in the stator gear 110 of the third prototype has a small impact on the peak torque of the asynchronous motor and can meet the performance requirements of the asynchronous motor. Subsequently, an NVH test can be further performed on the third prototype. Otherwise, the auxiliary slot 130 opened in the stator gear 110 of the third prototype is not used. 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 the first and second order electromagnetic forces are acquired based on this data. The first and second order electromagnetic forces of the third prototype are then compared with those of the first prototype to determine if the third prototype's first and second order electromagnetic forces are less than those of the first prototype. If so, it indicates that the auxiliary slot 130 on the stator gear 110 of the third prototype can effectively improve the first and second order whistling problem of the asynchronous motor, thus verifying that the auxiliary slot 130 of the third prototype is qualified; otherwise, it verifies that the auxiliary slot 130 of the third prototype is unqualified.

[0072] like Figure 4 As shown, in step S8, after all the third prototypes whose auxiliary slots 130 have been verified as qualified have obtained their first and second order electromagnetic forces, the first and second order electromagnetic forces of all the qualified third prototypes with auxiliary slots 130 are compared, and the auxiliary slot 130 of one of the third prototypes is selected as the optimized design. At this time, the further determined content can be the size of the auxiliary slot 130. Similarly, specifically, a third prototype with relatively small first and second order electromagnetic forces can be selected.

[0073] It is understood that by setting several auxiliary slots 130 of the third prototype to have the same shape but different sizes, the dimensions of the auxiliary slots 130 as an optimized design can be further determined to further improve the accuracy of slotting on the stator teeth 110 of the asynchronous motor.

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

[0075] S9. Prepare a fourth prototype of an asynchronous motor, wherein an auxiliary slot 130 is provided on the stator tooth portion 110 of the fourth prototype. The auxiliary slot 130 of the fourth prototype has the same shape and size as the auxiliary slot 130 of the third prototype. The depth of the auxiliary slot 130 along the radial direction of the stator on the stator tooth portion 110 of the fourth prototype is different from that of the third prototype. The auxiliary slot 130 is set into several groups of different depths along the radial direction of the stator on the stator tooth portion 110 to form several fourth prototypes.

[0076] S10. Sequentially acquire the external characteristic data of each fourth prototype, and acquire the 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, acquire the first and second order electromagnetic forces of the fourth prototype, and determine whether the first and second order electromagnetic forces of the fourth prototype are less than the first and second order electromagnetic forces of the first prototype; if so, verify that the auxiliary slot 130 of the fourth prototype is qualified.

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

[0078] like Figure 5 As shown in this embodiment, by way of example, in step S9, the preparation method of the fourth prototype is the same; at the same time, the shape and size of the auxiliary groove 130 of the fourth prototype are the shape of the auxiliary groove 130 as the optimized design determined by the second prototype and the size of the auxiliary groove 130 of the seat optimized design determined by the third prototype. The fourth prototype is also set to a plurality of them, and the depth of the auxiliary groove 130 of the plurality of fourth prototypes along the radial direction of the stator on the stator tooth portion 110 is different from each other, that is, the groove depth is different from each other.

[0079] like Figure 5 As shown, in step S10, similarly, after the fourth prototype is prepared, an external characteristic test is performed on the fourth prototype to obtain its peak torque. Then, the peak torque of the fourth prototype is 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 auxiliary slot 130 in the stator gear 110 of the fourth prototype has a small impact on the peak torque of the asynchronous motor and can meet the performance requirements of the asynchronous motor. Then, an NVH test is further performed on the fourth prototype. Conversely, the auxiliary slot 130 in the stator gear 110 of the fourth prototype is not used. In this embodiment, the preset value of 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 of the ratio of the peak torque of the second prototype to the peak torque of the first prototype, and the preset value of 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 the first and second order electromagnetic forces are acquired based on this data. The first and second order electromagnetic forces of the fourth prototype are then compared with those of the first prototype to determine if the fourth prototype's electromagnetic forces are less than those of the first prototype. If so, it indicates that the auxiliary slot 130 on the stator gear 110 of the fourth prototype can effectively improve the first and second order whistling problem of the asynchronous motor, thus verifying that the auxiliary slot 130 of the fourth prototype is qualified; otherwise, it verifies that the auxiliary slot 130 of the fourth prototype is unqualified.

[0081] like Figure 5 As shown, in step S11, after all the fourth prototypes whose auxiliary slots 130 have been verified as qualified have obtained their first and second order electromagnetic forces, the first and second order electromagnetic forces of all the qualified fourth prototypes with auxiliary slots 130 are compared, and the auxiliary slot 130 of one of the fourth prototypes is selected as the optimized design. At this time, the further determined content can be the slotting depth of the auxiliary slot 130, that is, the depth of the auxiliary slot 130 along the radial direction of the stator on the stator tooth 110. Similarly, specifically, a fourth prototype with relatively small first and second order electromagnetic forces can be selected.

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

[0083] More specifically, m=70, n=4, and the preset values ​​for 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, exemplarily, m can be 70, n can be 4, and the main NVH problem of the first prototype is the 66th and 70th order howling 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 of 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 is understandable that by reasonably setting the data relationship between the number of slots of the rotor and the number of poles of 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, this embodiment can ensure that the performance of the asynchronous motor under specified parameters can meet the usage requirements after the stator tooth 110 slotting optimization design.

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

[0087] like Figure 2 As shown in this embodiment, by way of example, the shape of the auxiliary groove 130 of the second prototype determined according to steps S1-S5 can be elliptical. In this case, the minor axis direction of the auxiliary groove 130 can be the radial direction of the stator, and the length direction of the auxiliary groove 130 can be the tangential direction of the stator. At the same time, the auxiliary groove 130 can be symmetrically arranged on the stator teeth 110.

[0088] More specifically, the auxiliary slot 130 of the third prototype, which is an optimized design, has an elliptical shape with a major axis of 1.6-2.0 mm and a minor axis of 0.5-0.9 mm.

[0089] like Figure 2 As shown in this embodiment, by way of 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 for the major axis and 0.5-0.9 mm for the minor axis, for example, 1.79 mm for the major axis and 0.7 mm for the minor axis. Of course, in some embodiments, the major axis and minor axis can also be other values.

[0090] More specifically, the auxiliary groove 130 of the fourth prototype, which is an optimized design, has a depth of 0.2-0.3 mm along the radial direction of the stator on the stator teeth 110.

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

[0092] like Figure 6 and Figure 7As shown, it has been verified that when an asynchronous motor with 70 rotor slots and 4 magnetic field poles has an auxiliary slot 130 with 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 stator radial direction on the stator tooth 110, under the condition of 100% external characteristic output of the asynchronous motor, a 3-18 dB reduction in the 66th order and a 3-15 dB reduction in the 70th order can be achieved, demonstrating a significant order noise optimization effect. (See attached...) Figure 6 and attached Figure 7 In the diagram, dashed lines represent data after slotting the asynchronous motor, while solid lines represent data before slotting the asynchronous motor.

[0093] Example 2

[0094] Embodiment 2 of this application provides a slotted structure for the stator teeth 110 of an asynchronous motor. The slotted structure for the stator teeth 110 of the asynchronous motor is formed by any of the slotting methods for the stator teeth of an asynchronous motor provided in this application.

[0095] Example 3

[0096] Embodiment 3 of this application provides an asynchronous motor, which includes any of the slotted structures of the stator teeth 110 of the asynchronous motor provided in this application.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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 embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for slotting the stator teeth of an asynchronous motor, characterized in that, The method for slotting the stator teeth of the asynchronous motor includes: Obtain the NVH measured data of the first prototype of the asynchronous motor, and obtain the 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 magnetic field poles formed by the rotor are 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. Obtain the external characteristic data of the first prototype, and obtain the 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 an auxiliary slot (130) is provided on the stator teeth (110) of the second prototype; and the auxiliary slot (130) is set into several different groups to form several second prototypes; The external characteristic data of each second prototype is obtained sequentially, and the peak torque of each second prototype is obtained 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, the first order and the second order electromagnetic forces of the second prototype are obtained, and it is determined whether the first order and the second order electromagnetic forces of the second prototype are less than the first order and the second order electromagnetic forces of the first prototype; if so, the auxiliary groove (130) of the second prototype is verified to be qualified; Compare the first and second order electromagnetic forces of all qualified second prototypes with the auxiliary groove (130), and determine the auxiliary groove (130) of the second prototype with relatively small first and second order electromagnetic forces 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 set into several different groups to form several second prototypes, including: A second prototype of the asynchronous motor is prepared, wherein the stator teeth (110) of the second prototype are provided with the auxiliary slots (130); the auxiliary slots (130) are set into several groups that are different from each other according to the shape of the auxiliary slots (130) to form several second prototypes; Compare the first-order and second-order electromagnetic forces of all qualified second prototypes with the auxiliary slot (130), and determine the auxiliary slot (130) of one second prototype with relatively small first-order and second-order electromagnetic forces as the optimized design, including: Compare the first and second order electromagnetic forces of all qualified second prototypes of the auxiliary groove (130), and determine the shape of the auxiliary groove (130) of one of the second prototypes with relatively small first and second order electromagnetic forces as an optimization design.

3. The method for slotting the stator teeth of an asynchronous motor according to claim 2, characterized in that, After comparing the first and second order electromagnetic forces of all qualified second prototypes with the auxiliary slot (130), and determining the shape of the auxiliary slot (130) of one of the second prototypes with relatively small first and second order electromagnetic forces as an optimized design, the grooving method for 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 have the same shape but different size as the auxiliary slots (130) of the second prototype; the auxiliary slots (130) are set into several groups that are different from each other according to the size of the auxiliary slots (130) of the third prototype, so as to form several third prototypes; The external characteristic data of each of the third prototypes are obtained sequentially, and the peak torque of each of the third prototypes is obtained based on 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, the first order and the second order electromagnetic forces of the third prototype are obtained, and it is determined whether the first order and the second order electromagnetic forces of the third prototype are less than the first order and the second order electromagnetic forces of the first prototype; if so, the auxiliary groove (130) of the third prototype is verified to be qualified; Compare the first 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 and second order electromagnetic forces 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 and second order electromagnetic forces of all the qualified third prototypes with the auxiliary slot (130), and determining the auxiliary slot (130) of one of the third prototypes with relatively small first and second order electromagnetic forces as the optimized design, the grooving method of the asynchronous motor stator teeth further includes: A fourth prototype of the asynchronous motor is prepared, wherein the stator teeth (110) of the fourth prototype are provided with the auxiliary groove (130), the auxiliary groove (130) of the fourth prototype is the same in shape and size as the auxiliary groove (130) of the third prototype, and the depth of the auxiliary groove (130) of the fourth prototype along the radial direction of the stator on the stator teeth (110) is different from that of the third prototype; the auxiliary groove (130) is set into several groups of different depths along the radial direction of the stator on the stator teeth (110) to form several fourth prototypes; The external characteristic data of each of the fourth prototypes are obtained sequentially, and the peak torque of each of the fourth prototypes is obtained based on 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, the first order and the second order electromagnetic forces of the fourth prototype are obtained, and it is determined whether the first order and the second order electromagnetic forces of the fourth prototype are less than the first order and the second order electromagnetic forces of the first prototype; if so, it is verified that the auxiliary groove (130) of the fourth prototype is qualified; Compare the first and second order electromagnetic forces of all the fourth prototypes that are qualified in the auxiliary slot (130), and determine the auxiliary slot (130) of the fourth prototype in which both the first and second order electromagnetic forces are relatively small 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 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%.

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, which is an optimized design, is elliptical in shape.

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

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

9. A slotted structure for the stator teeth of an asynchronous motor, characterized in that, The slotted structure of the stator teeth of the asynchronous motor is formed by the slotting method of the stator teeth of the asynchronous motor as described in any one of claims 1-8.

10. An asynchronous motor, characterized in that, The asynchronous motor includes the slotted structure of the stator teeth as described in claim 9.

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