Method for detecting the surface magnetization of a motor rotor

Abstract

This invention discloses a method for detecting the magnetic properties of a motor rotor, relating to the field of motors. The key technical points include circumferential and axial detection. The axial position of the first measuring end of the rotor is set as X0, the axial length between the first and second measuring ends of the rotor is L, the axial feed of the circumferential magnetometer is ΔX, the initial circumferential position of the rotor is θ0, and the circumferential feed of the axial magnetometer is Δθ. During detection: the circumferential magnetometer is moved to X0 for the first circumferential detection; the rotor is then rotated to θ0 for the first axial detection; the circumferential magnetometer is moved to X0+ΔX for the second circumferential detection; the rotor is then rotated to θ0+Δθ for the second axial detection; and so on. This invention can both expand the detection range and quickly and accurately report abnormal positions on the rotor.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more specifically, to a method for detecting the surface magnetic properties of an electric motor rotor. Background Technology

[0002] For permanent magnet motors, the current actual manufacturing process is difficult to match the design requirements. For example, the manufacturing process has a significant impact on the performance of permanent magnets and rotor laminations. Therefore, it is necessary to test the surface magnetic properties of the permanent magnet motor rotor after it is manufactured.

[0003] Existing magnetic field testing methods mainly include two types: The first type is vertical testing, in which the permanent magnet motor rotor is vertically mounted on a rotating component, and the rotor magnetic field is detected by a vertically movable teslameter or coil, as shown in Chinese Patent No. CN209264937U; The second type is horizontal testing, in which the permanent magnet motor rotor is mounted on a dynamic balancing machine, and the testing device is placed on the side or the rotor is directly placed in the stator, relying on the principle of electromagnetic induction for detection, as shown in Chinese Patent No. CN 216013598 U.

[0004] In addition, a Chinese patent with authorization announcement number CN110596622B discloses a rotor magnetic field detection method that simultaneously acquires magnetic field data and position data. By setting an incremental encoder on the rotating mechanism, the incremental encoder outputs position data to an AD conversion chip through A+, A-, B+, B-, Z+, and Z-. The AD conversion chip binds the received magnetic field data and position data one-to-one, and then sends the data to the application software to unbind the data in the binding order, analyze the position data, and obtain the one-to-one correspondence between the magnetic field data and position data, so as to realize the synchronous acquisition of rotor magnetic field data and position data by the gaussmeter.

[0005] However, based on the aforementioned patents, the existing magnetic field detection methods still have the following problems: 1. The purpose of detection is only to determine whether the data meets the design value. Therefore, a single detection device is generally used to move unidirectionally for detection. After the rotor surface is unfolded, it is rectangular. After the magnetic field data corresponds to the position data, the line connecting the detected data points forms a waveform curve in the rectangle. Compared with the entire rotor surface, the detection range fed back by the waveform curve is obviously insufficient, which makes it difficult or impossible to use the detected data for further production optimization and design optimization of rotor performance; 2. For rotors with abnormal detection data, rework is required. However, the detected data cannot quickly and accurately reflect the abnormal position on the rotor. Therefore, the rotor needs to be re-inspected to find the abnormal position before repair, resulting in low production efficiency.

[0006] Therefore, how to design a magnetic detection method that can both expand the detection range and quickly and accurately feed back the abnormal position on the rotor is an urgent problem to be solved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for detecting the surface magnetic properties of a motor rotor, which can both expand the detection range and quickly and accurately provide feedback on abnormal positions on the rotor.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for detecting the magnetic properties of a motor rotor, comprising:

[0010] Circumferential testing: During circumferential testing, the circumferential magnetometer remains stationary, and then the rotor is rotated one revolution.

[0011] Axial detection: During axial detection, the rotor remains stationary, and then the axial magnetometer is moved axially from one measuring end of the rotor to the other measuring end.

[0012] Settings: The axial position of the first measuring end of the rotor is X0, the axial length between the first measuring end and the second measuring end of the rotor is L, the axial feed of the circumferential magnetometer is ΔX, the initial circumferential position of the rotor is θ0, and the circumferential feed of the axial magnetometer is Δθ.

[0013] During testing:

[0014] Control the circumferential magnetometer to move to X0 and perform the first circumferential test; control the rotor to rotate to θ0 and perform the first axial test.

[0015] Control the circumferential magnetometer to move to X0+ΔX for a second circumferential test, and control the rotor to rotate to θ0+Δθ for a second axial test;

[0016] Control the circumferential magnetometer to move to X0+2ΔX and perform the third circumferential test; control the rotor to rotate to θ0+2Δθ and perform the third axial test.

[0017] This process continues until the circumferential magnetometer is moved to X0+nΔX for the (n+1)th circumferential detection, and the rotor is rotated to θ0+nΔθ for the (n+1)th axial detection.

[0018] Where n is a positive integer, and nΔX=L.

[0019] Furthermore, the method also includes:

[0020] Alarm for abnormal data;

[0021] The abnormal data includes circumferential abnormal data and axial abnormal data. If circumferential abnormal data is detected, position coordinates are formed based on the axial position of the circumferential magnetometer and the circumferential position of the abnormal data. If axial abnormal data is detected, position coordinates are formed based on the circumferential position of the rotor and the axial position of the abnormal data.

[0022] Furthermore, a set of circumferential magnetic measurements is collected during each circumferential inspection, and circumferential anomaly data is obtained based on multiple sets of circumferential magnetic measurements.

[0023] Furthermore, a set of circumferential magnetic measurements includes multiple circumferential magnetic measurements, and then circumferential anomaly data is obtained based on the circumferential magnetic measurements located at the same circumferential position on the rotor among the multiple sets of circumferential magnetic measurements.

[0024] Furthermore, a set of axial magnetic measurement values ​​is collected during each axial inspection, and axial anomaly data is obtained based on the axial magnetic measurement values ​​of the same set.

[0025] Furthermore, nΔθ = 360°.

[0026] Furthermore, the endpoint of the axial magnetic gauge's movement during this axial measurement will be the starting point for the axial magnetic gauge's movement during the next axial measurement.

[0027] Furthermore, during each circumferential inspection, the rotor starts rotating from the same position.

[0028] Furthermore, during a single circumferential inspection, the rotor starts rotating from the position of the previous axial inspection, and continues to rotate to the position of the next axial inspection after one revolution.

[0029] In summary, the present invention has the following beneficial effects:

[0030] 1. A circumferential magnetometer is used to sequentially detect different axial positions of the rotor, and an axial magnetometer is used to sequentially detect different circumferential positions of the rotor, thereby achieving comprehensive detection of the rotor surface. The rotor surface, when unfolded, forms a rectangle. Connecting the data points collected in each circumferential and axial detection creates a grid within the rectangle. Compared to the waveform curves in existing technologies, this invention expands the detection range of the rotor surface magnetism. Expanding the detection range allows for the acquisition of more detection data. Based on this data, a more precise analysis of the rotor surface magnetism can be performed, improving detection accuracy and enabling further production and design optimization of rotor performance.

[0031] 2. Each data point collected during testing has a corresponding position coordinate on the rotor. If a data point is abnormal, the position of the abnormal data point on the rotor can be quickly and accurately fed back, thereby improving the rotor's rework efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the rotor magnetic detection method in the embodiment. Figure 1 ;

[0033] Figure 2 This is a schematic diagram of the rotor magnetic detection method in the embodiment. Figure 2 . Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings.

[0035] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0036] Example:

[0037] A method for detecting the magnetic properties of a motor rotor, referring to Figure 1 and Figure 2 It includes:

[0038] Circumferential testing: During circumferential testing, the circumferential magnetometer remains stationary, and then the rotor is rotated one revolution.

[0039] Axial detection: During axial detection, the rotor remains stationary, and then the axial magnetometer is moved axially from one measuring end of the rotor to the other measuring end.

[0040] Settings: The axial position of the first measuring end of the rotor is X0, the axial length between the first and second measuring ends of the rotor is L, the axial feed of the circumferential magnetometer is ΔX, the initial circumferential position of the rotor is θ0, and the circumferential feed of the axial magnetometer is Δθ. During axial detection, the axial magnetometer only performs linear motion, so the circumferential feed is achieved through the rotation of the rotor, enabling the axial magnetometer to perform axial detection at different circumferential positions on the rotor.

[0041] During testing:

[0042] Control the circumferential magnetometer to move to X0 and perform the first circumferential test; control the rotor to rotate to θ0 and perform the first axial test.

[0043] Control the circumferential magnetometer to move to X0+ΔX for a second circumferential test, and control the rotor to rotate to θ0+Δθ for a second axial test;

[0044] Control the circumferential magnetometer to move to X0+2ΔX and perform the third circumferential test; control the rotor to rotate to θ0+2Δθ and perform the third axial test.

[0045] This process continues until the circumferential magnetometer is moved to X0+nΔX for the (n+1)th circumferential detection, and the rotor is rotated to θ0+nΔθ for the (n+1)th axial detection.

[0046] Where n is a positive integer, and nΔX=L.

[0047] In this embodiment, a circumferential magnetometer is used to sequentially perform circumferential detection at different axial positions of the rotor, and an axial magnetometer is used to sequentially perform axial detection at different circumferential positions of the rotor, thereby achieving comprehensive detection of the rotor surface. The rotor surface, when unfolded, forms a rectangle. Connecting the data points collected from each circumferential detection and connecting the data points collected from each axial detection, the intersecting lines form a grid within the rectangle (e.g., ...). Figure 1 and Figure 2 As shown in the figure, compared with the waveform curve in the prior art, the method in this embodiment expands the detection range of rotor surface magnetism. After expanding the detection range of rotor surface magnetism, more detection data can be obtained. Based on this data, the rotor surface magnetism can be analyzed more accurately, which not only improves the detection accuracy, but also enables further production optimization and design optimization of rotor performance.

[0048] Preferably, the method in this embodiment further includes an abnormal data alarm; wherein, the abnormal data includes circumferential abnormal data and axial abnormal data. When circumferential abnormal data is detected, position coordinates are formed based on the axial position of the circumferential magnetometer and the circumferential position of the abnormal data; when axial abnormal data is detected, position coordinates are formed based on the circumferential position of the rotor and the axial position of the abnormal data; based on the position coordinates, the position of the abnormal data on the rotor can be quickly and accurately fed back, thereby improving the rotor's rework efficiency.

[0049] Specifically, each circumferential detection data point corresponds to a circumferential magnetic measurement value. That is, a set of circumferential magnetic measurement values ​​is collected during each circumferential detection, and this set includes multiple circumferential magnetic measurement values. The circumferential magnetic measurement value, the axial position of the corresponding circumferential magnetic gauge, and the corresponding circumferential position of the rotor are bound together to form a data packet. Similarly, each axial detection data point corresponds to an axial magnetic measurement value. That is, a set of axial magnetic measurement values ​​is collected during each axial detection, and this set includes multiple axial magnetic measurement values. The axial magnetic measurement value, the axial position of the corresponding axial magnetic gauge, and the corresponding circumferential position of the rotor are bound together to form a data packet. In other words, in this embodiment, each data point collected during detection has a corresponding position coordinate on the rotor. If a data point is abnormal, its position on the rotor can be quickly and accurately fed back, thereby improving the rotor's rework efficiency.

[0050] Preferably, in this embodiment, circumferential abnormality data is obtained based on multiple sets of circumferential magnetic measurement values. Specifically, circumferential abnormality data is obtained based on circumferential magnetic measurement values ​​located at the same circumferential position on the rotor within the multiple sets of circumferential magnetic measurement values. Multiple circumferential magnetic measurement values ​​within the same set, when connected sequentially, resemble a sine curve. If the abnormality of a particular circumferential magnetic measurement value is determined based on the circumferential magnetic measurement values ​​within the same set (e.g., the variation range of the difference between adjacent circumferential magnetic measurement values), false alarms are likely to occur. However, multiple circumferential magnetic measurement values ​​at the same circumferential position on the rotor, when connected sequentially, resemble a straight line, thus enabling more accurate detection of abnormal data and reducing or avoiding false alarms. Specifically, during detection, the current set of circumferential magnetic measurement values ​​can be compared with the adjacent previous set of circumferential magnetic measurement values, and the difference is used to determine whether there is an abnormality in the current set of circumferential magnetic measurement values. Data; of course, after the detection is completed, analysis can be performed based on the circumferential magnetic measurement values ​​of all groups to identify abnormal data; preferably, in this embodiment, axial abnormal data is obtained based on the axial magnetic measurement values ​​of the same group. Specifically, during the detection, the current axial magnetic measurement value is compared with the previous axial magnetic measurement value, and the difference is used to determine whether the current axial magnetic measurement value is abnormal data; of course, after the detection is completed, analysis can be performed based on the axial magnetic measurement values ​​of the same group to identify abnormal data; in this embodiment, the detection of abnormal data is preferably applied to straight slot rotors. For skewed slot rotors, if the above method is to be used to identify abnormal data, the data needs to be corrected, that is, the data of the skewed slot rotor is corrected according to the straight slot rotor; of course, other methods can also be used to identify abnormal data for skewed slot rotors, which are not limited here.

[0051] Preferably, in this embodiment, nΔθ = 360°, which is beneficial to improving detection efficiency. The values ​​of ΔX and Δθ in this embodiment can be selected as needed and are not limited here. In this embodiment, the axial length between the first measuring end and the second measuring end of the rotor is L. If the axial length of the permanent magnet on the rotor is divisible, the two ends of the permanent magnet can be used as the first measuring end and the second measuring end, respectively, and L is equal to the axial length of the permanent magnet. If the axial length of the permanent magnet on the rotor is not divisible, one end of the permanent magnet can be used as the first measuring end, and then the position on the permanent magnet closer to the other end can be selected as the second measuring end. Of course, the positions of the first measuring end and the second measuring end can also be adjusted as needed, for example, to detect a section of the rotor, which is not limited here.

[0052] Preferably, in this embodiment, during a single circumferential inspection, the rotor starts rotating from the position of the previous axial inspection, and continues rotating to the position of the next axial inspection after one revolution. This helps improve inspection efficiency. At this point, starting from the third circumferential inspection, the starting position of each circumferential inspection is different (e.g., ...). Figure 2 As shown, to facilitate data analysis and identify abnormal data, a set of circumferential magnetic measurement values ​​can be corrected as a whole. For example, the set of circumferential magnetic measurement values ​​can be translated as a whole in a coordinate system (circumferential position is the horizontal axis). Of course, in other optional embodiments, the rotor can also start rotating from the same position each time a circumferential test is performed, which is not limited here. Preferably, the endpoint of the movement of the axial magnetic meter during the current axial test is the starting point of the movement of the axial magnetic meter during the next axial test, which is beneficial to improving the detection efficiency.

Claims

1. A method for detecting the surface magnetic properties of a motor rotor, characterized in that, include: Circumferential testing: During circumferential testing, the circumferential magnetometer remains stationary, and then the rotor is rotated one revolution. Axial detection: During axial detection, the rotor remains stationary, and then the axial magnetometer is moved axially from one measuring end of the rotor to the other measuring end. Settings: The axial position of the first measuring end of the rotor is X0, the axial length between the first measuring end and the second measuring end of the rotor is L, the axial feed of the circumferential magnetometer is ΔX, the initial circumferential position of the rotor is θ0, and the circumferential feed of the axial magnetometer is Δθ. During testing: Control the circumferential magnetometer to move to X0 and perform the first circumferential test; control the rotor to rotate to θ0 and perform the first axial test. Control the circumferential magnetometer to move to X0+ΔX for a second circumferential test, and control the rotor to rotate to θ0+Δθ for a second axial test; Control the circumferential magnetometer to move to X0+2ΔX and perform the third circumferential test; control the rotor to rotate to θ0+2Δθ and perform the third axial test. This process continues until the circumferential magnetometer is moved to X0+nΔX for the (n+1)th circumferential detection, and the rotor is rotated to θ0+nΔθ for the (n+1)th axial detection. Where n is a positive integer, and nΔX=L; The method further includes: Alarm for abnormal data; The abnormal data includes circumferential abnormal data and axial abnormal data. When circumferential abnormal data is detected, position coordinates are formed based on the axial position of the circumferential magnetometer and the circumferential position of the abnormal data. When axial abnormal data is detected, position coordinates are formed based on the circumferential position of the rotor and the axial position of the abnormal data. Each circumferential inspection collects a set of circumferential magnetic measurement values, and then circumferential anomaly data is obtained based on multiple sets of circumferential magnetic measurement values; Each axial inspection collects a set of axial magnetic measurement values, and then axial anomaly data is obtained based on the axial magnetic measurement values ​​of the same set.

2. The method for detecting the surface magnetic properties of a motor rotor according to claim 1, characterized in that: A set of circumferential magnetic measurements includes multiple circumferential magnetic measurements. Then, circumferential anomaly data is obtained based on the circumferential magnetic measurements located at the same circumferential position on the rotor from the multiple sets of circumferential magnetic measurements.

3. The method for detecting the surface magnetic properties of a motor rotor according to claim 1, characterized in that: nΔθ=360°.

4. The method for detecting the surface magnetic properties of a motor rotor according to claim 1, characterized in that: The endpoint of the axial magnetometer during this axial measurement will be the starting point for the next axial measurement.

5. The method for detecting the surface magnetic properties of a motor rotor according to claim 1, characterized in that: During each circumferential inspection, the rotor starts rotating from the same position.

6. The method for detecting the surface magnetic properties of a motor rotor according to claim 1, characterized in that: When performing a single circumferential inspection, the rotor starts rotating from the position of the previous axial inspection, and continues to rotate to the position of the next axial inspection after one revolution.

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