Magnetostrictive noise source confirmation method and core production method

Abstract

This invention relates to a method for identifying magnetostrictive noise sources and a method for producing iron cores. The method for identifying magnetostrictive noise sources includes the following steps: performing magnetostrictive and Maxwell force tests on both longitudinally and transversely cut samples to obtain test data, calculating the theoretical noise of the longitudinally and transversely cut samples, confirming that the theoretical noise of the longitudinally and transversely cut samples is consistent, and comparing it with the actual noise of the product; the actual noise of the product is obtained by conducting noise tests on iron core products made of silicon steel sheets; if the theoretical noise of the sample is consistent with the actual noise of the product, the unacceptable noise originates from a material problem; if the theoretical noise of the sample is inconsistent with the actual noise of the product, the unacceptable noise originates from a structural problem. This invention can accurately locate the source of noise problems in the production process.

Description

Technical Field

[0001] This invention relates to the field of transformers, and more specifically to a method for identifying magnetostrictive noise sources and a method for producing iron cores. Background Technology

[0002] Currently, it is widely believed that the vibration noise of power transformer cores is caused by the magnetostriction of silicon steel sheets. However, magnetostriction only refers to the vertical change of silicon steel sheets in an alternating magnetic field. The horizontal change of silicon steel sheets in an alternating magnetic field, i.e., the horizontal vibration of silicon steel sheets caused by Maxwell's force, is also one of the main sources of core vibration noise.

[0003] There is no clear method in the current technology to identify the source of noise during the core production process, so it is impossible to precisely control noise during core production. Whether there is noise and how much noise it is depends entirely on the actual noise of the produced core, and cannot guide the factory to produce low-noise core products in terms of materials or structure. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a method for identifying magnetostrictive noise sources and a method for producing iron cores.

[0005] The technical solutions adopted in the embodiments of the present invention are as follows:

[0006] A method for identifying magnetostrictive noise sources includes the following steps:

[0007] Magnetostriction and Maxwell force tests were performed on both longitudinally cut and transversely cut samples to obtain test data. The longitudinally cut samples were obtained by longitudinally cutting silicon steel coils and taking samples during the manufacturing process of silicon steel sheets. The transversely cut samples were obtained by transversely cutting silicon steel coils and taking samples during the manufacturing process of silicon steel sheets.

[0008] If the test data of the cross-section sample and the longitudinal section sample are the same, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively. When the theoretical noise of the longitudinal section sample and the cross-section sample are consistent, compare the theoretical noise of the sample with the actual noise of the product; the actual noise of the product is obtained by noise testing the iron core product made of silicon steel sheet.

[0009] If the theoretical noise of the sample matches the actual noise of the product, the unacceptable noise originates from a material problem; if the theoretical noise of the sample does not match the actual noise of the product, the unacceptable noise originates from a structural problem.

[0010] A further technical solution is that the steps further include:

[0011] If the test data of the cross-section sample and the longitudinal section sample are different, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively, and compare the theoretical noise of the cross-section sample and the longitudinal section sample with the actual noise of the product respectively. If the theoretical noise of the longitudinal section sample is the same as the product test noise, the unqualified noise comes from the cross-section process problem. If the theoretical noise of the cross-section sample is the same as the product test noise, the unqualified noise comes from the longitudinal section process problem. If the theoretical noise of both the cross-section sample and the longitudinal section sample is inconsistent with the actual noise of the product, the unqualified noise comes from the material problem.

[0012] The further technical solution is that the calculation of the theoretical noise of the sample specifically includes: calculating the noise based on the magnetostrictive performance test results of the sample and the magnetostrictive noise curve corrected by Maxwell force.

[0013] A method for producing iron cores includes the following steps:

[0014] The silicon steel coil was longitudinally cut, and longitudinal samples were taken during the cutting process to obtain longitudinal samples;

[0015] Silicon steel coils are cross-cut to obtain silicon steel sheets, and cross-cut samples are taken during the cross-cutting process to obtain cross-cut samples;

[0016] Silicon steel sheets are made into iron core products, and noise tests are conducted to obtain actual noise data of the products. If the actual noise data of the products is qualified, the products are shipped out of the factory. If the actual noise data of the products is unqualified, the noise source is identified. The steps for identifying the noise source are as described in any of the above magnetostrictive noise source identification methods.

[0017] A further technical solution includes the following steps before the longitudinal cutting step:

[0018] Determine the core type;

[0019] The production of iron cores involves selecting silicon steel sheets based on the type of iron core.

[0020] The lamination factor is tested. If the lamination factor meets the predetermined requirements, the iron loss performance test is carried out. If the lamination factor does not meet the predetermined requirements, silicon steel sheets are selected again.

[0021] If the iron loss performance meets the predetermined requirements, then the magnetostrictive performance test is performed; if the iron loss performance does not meet the predetermined requirements, then silicon steel sheets are selected again.

[0022] Magnetostrictive performance testing is performed, and the theoretical noise of the silicon steel material is calculated. If the theoretical noise meets the predetermined requirements, a shearing scheme is output; if the theoretical noise does not meet the requirements, a new silicon steel sheet is selected.

[0023] The further technical solution is that the calculation of the material theoretical noise of silicon steel material specifically includes: testing the magnetostriction performance of silicon steel material and calculating it based on the magnetostriction noise curve corrected by Maxwell force.

[0024] A further technical solution is to monitor the thickness of the silicon steel sheet and the unit iron loss performance of the silicon steel sheet in real time during the longitudinal and transverse cutting processes.

[0025] A further technical solution is as follows: In the noise source confirmation step, if the test data of the transverse and longitudinal samples are the same, the theoretical noise of the transverse and longitudinal samples is calculated respectively. When the theoretical noise of the longitudinal and transverse samples is consistent, the theoretical noise of the samples is compared with the actual noise of the product. If the theoretical noise of the samples is consistent with the actual noise of the product, the unqualified noise comes from a material problem, the material is replaced, and silicon steel sheets are reselected. If the theoretical noise of the samples is inconsistent with the actual noise of the product, the unqualified noise comes from a structural problem, the core design structure is changed, and the core type is re-determined.

[0026] A further technical solution is as follows: In the noise source identification step, if the test data of the cross-section sample and the longitudinal section sample are different, the theoretical noise of the cross-section sample and the longitudinal section sample are calculated respectively, and the theoretical noise of the cross-section sample and the longitudinal section sample are compared with the actual noise of the product respectively; if the theoretical noise of the longitudinal section sample is the same as the product test noise, the unqualified noise comes from the cross-section process problem; if the theoretical noise of the cross-section sample is the same as the product test noise, the unqualified noise comes from the longitudinal section process problem; if the theoretical noise of both the cross-section sample and the longitudinal section sample is inconsistent with the actual noise of the product, the unqualified noise comes from the material problem; when the unqualified noise comes from the cross-section process problem or the longitudinal section process problem, the production line instrument is repaired; when the unqualified noise comes from the material problem, the material is replaced and a new silicon steel sheet is selected.

[0027] The further technical solution is that the core production material preparation step specifically includes: if the core type is a distribution transformer core, the thickness of the silicon steel sheet is 0.18mm to 0.2mm; if the core type is a main transformer core, the thickness of the silicon steel sheet is 0.23mm to 0.27mm.

[0028] The beneficial effects of the embodiments of the present invention are as follows:

[0029] The embodiments of the present invention solve the problem of the specific sources of core noise.

[0030] Compared to the current rudimentary methods for determining noise sources, the embodiments of the present invention can accurately locate the source of noise.

[0031] Meanwhile, in this embodiment of the invention, the theoretical noise of the transformer core is calculated by correcting for the magnetostrictive effect of silicon steel sheets and Maxwell's force. This allows for advance prediction of whether the transformer core noise will match the design value. This avoids manufacturing rework time and greatly improves production efficiency. Furthermore, the theoretical noise testing of samples also serves as a process for collecting material parameters, providing a stable data source for the development of next-generation products.

[0032] In embodiments of the present invention, based on the magnetostriction and dynamic magnitude of the Maxwell force of the material at various locations, it is possible to determine whether processing problems have occurred on the production line, thereby reducing losses in transformer core production and improving material utilization. This also improves product quality. Attached Figure Description

[0033] Figure 1 This is a flowchart of the magnetostrictive noise source identification method in an embodiment of the present invention.

[0034] Figure 2 This is a flowchart of another embodiment of the magnetostrictive noise source identification method in this invention.

[0035] Figure 3 This is a flowchart of the iron core production method in an embodiment of the present invention. Detailed Implementation

[0036] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0037] Example 1.

[0038] Example 1 discloses a method for identifying magnetostrictive noise sources. Figure 1 This is a flowchart of the magnetostrictive noise source identification method in an embodiment of the present invention. Figure 1 As shown, Example 1 includes the following steps:

[0039] Step 101: Perform magnetostriction and Maxwell force tests on both the longitudinal and transverse samples; wherein:

[0040] Longitudinal samples are obtained by longitudinally slicing silicon steel coils during the silicon steel sheet manufacturing process and taking samples from these slices. Specifically, in the silicon steel coil longitudinal slicing production process, random samples are taken from the longitudinally sliced ​​silicon steel coils, and the sampling location is recorded. The sampling location is relative to the position of the longitudinally sliced ​​silicon steel coil. For example, silicon steel coil A is longitudinally sliced ​​to obtain silicon steel coil B, and during this process, a random sample A is obtained, and the sampling location is recorded as x meters from silicon steel coil B. Further, longitudinal sample A is processed according to laboratory sample preparation specifications, and the processed sample is designated as longitudinal sample C.

[0041] A cross-section sample is obtained by cross-slicing a longitudinally cut silicon steel coil during the silicon steel sheet manufacturing process, and then sampling the sample. Specifically, in the cross-slicing production process of silicon steel coils, random samples are taken from the cross-sliced ​​silicon steel coils, and the sampling position is recorded. The sampling position is relative to the position of the longitudinally cut silicon steel coil. For example, silicon steel coil B is cross-sliced ​​to obtain silicon steel sheet A, and simultaneously, a random sample B is obtained during this process, and the sampling position is recorded as y meters from silicon steel coil B. Further, the cross-section sample B is processed according to laboratory sample preparation specifications, and the processed sample is designated as cross-section sample D.

[0042] For example, magnetostriction and Maxwell force tests can be performed using laser displacement vibration sensors.

[0043] Step 102: If the measured data are the same, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively. When the theoretical noise of the longitudinal section sample and the cross-section sample are consistent, compare the theoretical noise of the sample with the actual noise of the product. The actual noise of the product is obtained by conducting noise tests on the iron core product made of silicon steel sheets and fittings in a soundproof room. Fittings may include clamps, auxiliary clamps, and screws made according to the design drawings.

[0044] The theoretical noise of the sample is calculated based on the magnetostrictive performance test results of the sample, using the magnetostrictive noise curve corrected for Maxwell's force. The magnetostrictive noise curve corrected for Maxwell's force can be obtained through experience and experimental data. For example, after the silicon steel sheet is manufactured into a finished iron core, the horizontal displacement of the silicon steel sheet is measured using a laser displacement sensor, thereby determining the dynamic magnitude of the Maxwell's force. This allows the determination of the noise generated by the Maxwell's force and the magnetostrictive force, thus obtaining the magnetostrictive noise curve corrected for Maxwell's force.

[0045] In this step, the theoretical noise of the longitudinally cut sample C and the transversely cut sample D shown above is calculated, and the theoretical noise of the longitudinally cut sample C and the transversely cut sample D is compared. After confirming that the theoretical noise of the longitudinally cut sample C and the transversely cut sample D are consistent, the theoretical noise of the longitudinally cut sample C or the transversely cut sample D is compared with the actual noise of the product.

[0046] Step 103: If the theoretical noise of the sample is consistent with the actual noise of the product, the noise source is located as a material problem; if the theoretical noise of the sample is inconsistent with the test noise of the product, the noise source is located as a structural problem.

[0047] By using steps 101 to 103, the source of noise can be preliminarily located if the test data of the transverse and longitudinal samples are consistent.

[0048] Building upon the steps described above, further, after step 101, the following is also included:

[0049] Step 104: If the measured data are different, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively, and compare the theoretical noise of the cross-section sample and the longitudinal section sample with the actual noise of the product respectively. If the theoretical noise of the longitudinal section sample is the same as the product test noise, then there is a problem with the cross-section. If the theoretical noise of the cross-section sample is the same as the product test noise, then there is a problem with the longitudinal section. If the theoretical noise of both the cross-section sample and the longitudinal section sample is inconsistent with the actual noise of the product, then there is a material problem.

[0050] Step 104, based on step 101, is a further judgment made regarding the situation where the magnetostriction and Maxwell force test results of the longitudinally cut sample differ from those of the transversely cut sample. For example, this involves calculating the theoretical noise of the longitudinally cut sample C and the transversely cut sample D as shown above, and comparing them with the actual noise of the product. If the problem is determined to be in the transverse or longitudinal section, it means that the production line equipment needs to be inspected during production. If the problem is determined to be in the material section, it means that the material needs to be replaced during production.

[0051] Example 2.

[0052] Based on Example 1, Example 2 discloses a method for producing iron cores, including the following steps:

[0053] Step 201: Determine the core type based on the core design drawing.

[0054] Step 202: Core production and material selection. Silicon steel sheets are selected based on the core type. For example, for distribution transformer cores, thin silicon steel sheets are used, typically with a thickness of 0.18mm to 0.2mm. For main transformer cores, thick silicon steel sheets are used, typically with a thickness of 0.23mm to 0.27mm.

[0055] Step 203: Lamination factor test. For example, a national standard lamination factor tester can be used. If the lamination factor meets the predetermined requirements, then an iron loss performance test is performed; if the lamination factor does not meet the predetermined requirements, then silicon steel sheets are reselected.

[0056] Step 204: Iron loss performance test. For example, this can be measured using a unit iron loss tester. If the unit iron loss performance meets the predetermined requirements, then a magnetostrictive performance test is performed; if the unit iron loss performance does not meet the predetermined requirements, then a new silicon steel sheet is selected.

[0057] Step 205: Magnetostrictive performance test and calculation of material theoretical noise. Material theoretical noise is calculated based on the Maxwell force-corrected magnetostrictive noise curve after obtaining the material's magnetostrictive performance. If the material theoretical noise meets the predetermined design requirements, a shearing scheme is output; otherwise, a new silicon steel sheet is selected.

[0058] Step 206: Slitting of Silicon Steel Coils. Select silicon steel coils according to the shearing plan. Proceed to the slitting production process for silicon steel coils. Preferably, during the slitting process, a silicon steel sheet unit area scanning device is used to monitor the silicon steel sheet thickness and unit iron loss performance in real time.

[0059] In the slitting process of silicon steel coils, random samples are taken from the slitting silicon steel coils to obtain slitting samples, and the sampling positions are recorded. The sampling position is the position of the slitting sample relative to the slitting silicon steel coil.

[0060] For example, silicon steel coil A is longitudinally cut to obtain silicon steel coil B. Simultaneously, a random sample A is taken during this process, and the sampling location is recorded as x meters from silicon steel coil B. Further, the longitudinally cut sample A is processed according to laboratory sample preparation specifications, and the processed sample is designated as longitudinally cut sample C.

[0061] Step 207: Cross-cutting of silicon steel coils. The longitudinally cut silicon steel coils are then cross-cut. Preferably, during the cross-cutting process, a silicon steel sheet unit area scanning device is used to monitor the silicon steel sheet thickness and unit iron loss performance in real time.

[0062] In the cross-cutting production process of silicon steel coils, random samples are taken from the cross-cut silicon steel coils to obtain cross-cut samples, and the sampling positions are recorded. The sampling position is relative to the position of the longitudinally cut silicon steel coil.

[0063] For example, silicon steel coil B is cross-cut to obtain silicon steel sheet A. Simultaneously, a random sample B is taken during this process, and the sampling location is recorded as y meters from silicon steel coil B. Further, the cross-cut sample B is processed according to laboratory sample preparation specifications, and the processed sample is designated as cross-cut sample D.

[0064] Step 208: Enter the noise testing benchmarking system, fabricate the silicon steel sheet A and accessories (clamps, auxiliary clamps, and screws made according to the design drawings) into a finished iron core, and transport the finished iron core to a soundproof room for noise testing to obtain the actual noise of the product. If the actual noise of the product meets the preset qualified standard, it meets the factory standard and the product can be shipped. If the actual noise test of the product fails, proceed to the noise source identification step.

[0065] The noise source identification steps have been disclosed in Embodiment 1, see steps 101 to 103 or steps 101 and 104 in Embodiment 1.

[0066] In this embodiment, before the transverse and longitudinal slicing, the theoretical noise of the transformer core is calculated simultaneously using the magnetostrictive effect of silicon steel sheets and the correction of Maxwell's force. This allows for advance prediction of whether the transformer core noise matches the design value. This avoids manufacturing rework time and significantly improves production efficiency. Simultaneously, the collection of material parameters provides a stable data source for the development of next-generation products.

[0067] This embodiment can accurately locate the source of noise. Based on the magnetostriction and Maxwell force dynamics of the material at various locations, it can determine whether there are processing problems on the production line, thereby reducing losses in transformer core production and improving material utilization. It also improves product quality.

[0068] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. The present invention can be modified in any form without departing from its basic structure.

Claims

1. A method for identifying magnetostrictive noise sources, characterized in that, Includes the following steps: Magnetostriction and Maxwell force tests were performed on both longitudinally cut and transversely cut samples to obtain test data. The longitudinally cut samples were obtained by longitudinally cutting silicon steel coils and taking samples during the manufacturing process of silicon steel sheets. The transversely cut samples were obtained by transversely cutting silicon steel coils and taking samples during the manufacturing process of silicon steel sheets. If the test data of the cross-section sample and the longitudinal section sample are the same, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively. When the theoretical noise of the longitudinal section sample and the cross-section sample are consistent, compare the theoretical noise of the sample with the actual noise of the product. The actual noise level of the product was obtained by conducting noise tests on the iron core product made of silicon steel sheets. If the theoretical noise of the sample matches the actual noise of the product, then the unqualified noise comes from a material problem. If the theoretical noise of the sample does not match the actual noise of the product, then the unqualified noise comes from a structural problem.

2. The method for identifying magnetostrictive noise sources according to claim 1, characterized in that, The steps further include: If the test data of the cross-section sample and the longitudinal section sample are different, calculate the theoretical noise of the cross-section sample and the longitudinal section sample respectively, and compare the theoretical noise of the cross-section sample and the longitudinal section sample with the actual noise of the product respectively. If the theoretical noise of the longitudinal section sample is the same as the product test noise, the unqualified noise comes from the cross-section process problem. If the theoretical noise of the cross-section sample is the same as the product test noise, the unqualified noise comes from the longitudinal section process problem. If the theoretical noise of both the cross-section sample and the longitudinal section sample is inconsistent with the actual noise of the product, the unqualified noise comes from the material problem.

3. The method for identifying magnetostrictive noise sources according to claim 1, characterized in that, The calculation of the theoretical noise of the sample specifically includes: calculating the noise based on the magnetostrictive performance test results of the sample and the magnetostrictive noise curve corrected by Maxwell force.

4. A method for producing iron cores, characterized in that, Includes the following steps: The silicon steel coil was longitudinally cut, and longitudinal samples were taken during the cutting process to obtain longitudinal samples; Silicon steel coils are cross-cut to obtain silicon steel sheets, and cross-cut samples are taken during the cross-cutting process to obtain cross-cut samples; Silicon steel sheets are made into iron core products, and noise tests are conducted to obtain the actual noise data of the products. If the actual noise data of the product is qualified, the product is shipped out; if the actual noise data of the product is not qualified, the noise source is identified. The noise source identification steps are as described in the magnetostrictive noise source identification method of any one of claims 1 to 3.

5. The method for producing iron cores according to claim 4, characterized in that, Prior to the longitudinal cutting step, the following steps are also included: Determine the core type; The production of iron cores involves selecting silicon steel sheets based on the type of iron core. The lamination factor is tested. If the lamination factor meets the predetermined requirements, the iron loss performance test is carried out. If the lamination factor does not meet the predetermined requirements, silicon steel sheets are selected again. If the iron loss performance meets the predetermined requirements, then the magnetostrictive performance test is performed; if the iron loss performance does not meet the predetermined requirements, then silicon steel sheets are selected again. Magnetostrictive performance testing is performed, and the theoretical noise of the silicon steel material is calculated. If the theoretical noise meets the predetermined requirements, a shearing scheme is output; if the theoretical noise does not meet the requirements, a new silicon steel sheet is selected.

6. The method for producing iron cores according to claim 5, characterized in that, The calculation of the material theory noise of silicon steel includes: testing the magnetostrictive properties of silicon steel and calculating the noise based on the magnetostrictive noise curve corrected by Maxwell force.

7. The method for producing iron cores according to claim 5, characterized in that, During the longitudinal and transverse cutting processes, the thickness of the silicon steel sheet and the unit iron loss performance of the silicon steel sheet are monitored in real time.

8. The method for producing iron cores according to claim 5, characterized in that, In the noise source identification step, if the test data of the cross-section sample and the longitudinal section sample are the same, the theoretical noise of the cross-section sample and the longitudinal section sample are calculated respectively. When the theoretical noise of the longitudinal section sample and the cross-section sample are consistent, the theoretical noise of the sample is compared with the actual noise of the product. If the theoretical noise of the sample matches the actual noise of the product, then the unqualified noise comes from a material problem. The material should be replaced and silicon steel sheets should be selected again. If the theoretical noise of the sample is inconsistent with the actual noise of the product, the unqualified noise comes from a structural problem. The core design structure should be changed and the core type should be redefined.

9. The method for producing iron cores according to claim 5, characterized in that, In the noise source identification step, if the test data of the cross-section sample and the longitudinal section sample are different, the theoretical noise of the cross-section sample and the longitudinal section sample are calculated respectively, and the theoretical noise of the cross-section sample and the longitudinal section sample are compared with the actual noise of the product respectively. If the theoretical noise of the longitudinally cut sample is the same as the product test noise, then the unacceptable noise comes from the cross-cutting process. If the theoretical noise of the cross-section sample is the same as the product test noise, then the unacceptable noise comes from the longitudinal cutting process. If the theoretical noise of both the cross-section sample and the longitudinal section sample is inconsistent with the actual noise of the product, then the unqualified noise comes from a material problem; when the unqualified noise comes from a cross-section process problem or a longitudinal section process problem, then the production line equipment should be repaired. If the substandard noise is due to a material problem, then the material should be replaced and silicon steel sheets should be selected again.

10. The method for producing iron cores according to claim 5, characterized in that, The core production and material preparation steps specifically include: if the core type is a distribution transformer core, the thickness of the silicon steel sheet is 0.18mm to 0.2mm; if the core type is a main transformer core, the thickness of the silicon steel sheet is 0.23mm to 0.27mm.

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