Method and device for detecting interlaminar insulation performance of an ultra-thin silicon steel wound core

Abstract

The application relates to a kind of detection method and device of interlayer insulation performance of ultrathin silicon steel winding core.The method simulates high-voltage pulse;the insulation layer of the core to be measured is impacted by high-voltage pulse, and the core to be measured is obtained in advance;the first peak current and the trough current of the core to be measured are obtained, and the corresponding positive and negative current ratio is calculated;the positive and negative current ratio is obtained multiple times;when the change of the positive and negative current ratio relative to the first calculation meets the preset condition, it is determined that the interlayer insulation of the core to be measured is damaged.Compared with the prior art, the application has the advantages of quickly screening out the core with damaged interlayer insulation, avoiding the risk of large loss caused by insulation damage after electromagnetic element packaging, etc.

Description

Technical Field

[0001] This invention relates to the field of insulation testing technology, and in particular to a method and apparatus for testing the interlayer insulation performance of an ultra-thin silicon steel wound core. Background Technology

[0002] Silicon steel is a low-silicon iron soft magnetic alloy with a carbon content of 0.5% to 4.5%. It possesses characteristics such as high permeability, low coercivity, and high resistivity, resulting in low hysteresis and eddy current losses. It is primarily used as a magnetic material in motors, transformers, reactors, and electrical instruments. The performance requirements for cold-rolled silicon steel sheets used in wound cores include low iron loss, high magnetic flux density, and a smooth, flat surface. These characteristics contribute to improving the efficiency and performance of transformers, reactors, and other products. When electromagnetic devices operate, they generate induced currents that circulate in a plane perpendicular to the magnetic flux. These induced currents form eddy currents in the core, leading to energy loss. In practical applications, cold-rolled silicon steel sheets are typically coated with an insulating coating, and the core is constructed by winding or stacking thin steel sheets coated with this insulating coating. Through processes such as vacuum impregnation, the flow path of eddy currents in the core cross-section is reduced, and the resistance along the path is increased, thereby reducing eddy current losses.

[0003] The insulation between adjacent layers of silicon steel sheets in an ultra-thin silicon steel wound core is called interlayer insulation. During core processing, defects such as unevenness and bubbles may occur in the interlayer insulation. Damage to the coating may also occur due to humidity, high temperatures, or chemical substances during storage, leading to interlayer insulation failure. This damage causes contact between adjacent silicon steel sheets, forming a low-impedance path. This creates current loops in the path, resulting in significant eddy current effects and increased core losses. Therefore, timely detection of interlayer insulation damage is essential for preventing substantial core losses.

[0004] Common methods for testing the interlayer insulation performance of silicon steel sheet cores include: 1. Infrared thermal imaging indirect detection: This method uses an infrared thermal imager to detect the heat distribution of the core during operation. Abnormal hot spots may indicate insulation problems. While this method can visually display areas of poor insulation, it is greatly affected by the environment and equipment accuracy. It can only detect cores in operation and not enclosed in a casing, and is not suitable for detecting cores in non-operational states. 2. Insulation resistance test: This method uses a megohmmeter (high resistance meter) to measure the insulation resistance value of the laminated sheets to determine the insulation condition. Due to the very low test voltage, this method cannot fully reflect the true condition of the interlayer insulation of the silicon steel sheets in actual operating conditions and is not sensitive to the detection of minor defects or localized insulation deficiencies.

[0005] Therefore, how to improve the accuracy of insulation testing and make it applicable to iron cores in non-operational states, so as to effectively avoid large iron core losses in advance, has become a problem that needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art by providing a method and apparatus for testing the interlayer insulation performance of ultra-thin silicon steel wound cores. This method is applicable to insulation testing of cores in non-operational states and can improve the accuracy of insulation testing, thereby avoiding large core losses in advance.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] According to a first aspect of the present invention, a method for detecting the interlayer insulation performance of an ultrathin silicon steel wound core is provided. The method includes the following steps: S1, simulating a high-voltage pulse; S2, using the high-voltage pulse to impact the insulation layer of the core under test, wherein the core under test is pre-acquired; S3, acquiring the current first peak current and trough current of the core under test, and calculating the corresponding positive-reverse current ratio; S4, repeating S1 to S3 to acquire multiple positive-reverse current ratios; S5, when the comparison result of the last calculation and the first calculation of the positive-reverse current ratio meets a preset condition, determining that the interlayer insulation of the core under test is damaged.

[0009] As a preferred technical solution, the preset condition includes that the ratio of forward to reverse current in the last calculation is less than 95% of the ratio of forward to reverse current in the first calculation.

[0010] According to a second aspect of the present invention, a testing device for the interlayer insulation performance of an ultra-thin silicon steel wound core is provided. The device is used to implement the method described above. The device includes an impact system control console, a high-voltage impact capacitor, a current sensing loop, a capacitive voltage divider, an insulating platform, and a test coil. A pre-acquired core to be tested is installed inside the test coil. The test coil is placed on the insulating platform, one end of which is connected to a high voltage, and the other end is grounded. The test coil is connected to the high-voltage impact capacitor, and the current sensing loop is sleeved on the connecting line between the two. The interface end of the current sensing loop is connected to the impact system control console. The capacitive voltage divider is connected between the test coil and the impact system control console. The high-voltage impact capacitor is connected to the impact system control console.

[0011] As a preferred technical solution, the impact system control console also includes an oscilloscope.

[0012] As a preferred technical solution, the interior of the insulating platform is provided with a slot, and a flip plate, a first support element and a telescopic block are arranged sequentially from top to bottom in the slot. The flip plate and the telescopic block are connected through the first support element.

[0013] As a preferred technical solution, a second support element is provided on the side surface of the flip plate, the flip plate is connected to the inner wall of the insulating platform through the second support element, a first handle is fixedly connected to the upper surface of the flip plate, and a second handle is fixedly connected to the outer surface of the insulating platform.

[0014] As a preferred technical solution, the insulating platform further includes a plug-in block and an extension ring, wherein the plug-in block is plugged into the flip plate and the extension ring is fixedly connected to the inner wall of the insulating platform.

[0015] As a preferred technical solution, the two ends of the plug block are fixedly connected to vibration plates, and the bottom is fixedly connected to an extension block.

[0016] As a preferred technical solution, the bottom of the extension ring is connected to a fixed elastic element.

[0017] As a preferred technical solution, the diameter of the vibrating plate is larger than the diameter of the plug block.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The detection method proposed in this invention applies several high-voltage impacts to the iron core under test, which approximate actual operating conditions. Based on the ratio of the positive and negative currents obtained from the first and last measurements, the interlayer insulation performance of the iron core under test can be quickly determined. This method is suitable for insulation testing of iron cores in non-operating states. On the one hand, applying high-voltage pulses that approximate actual operating conditions helps to comprehensively reflect the true situation of interlayer insulation of silicon steel sheets in iron cores under actual operating conditions, improves the sensitivity to the detection of minor defects or local insulation failures, and thus improves the accuracy of insulation testing. On the other hand, it can quickly screen out iron cores with damaged interlayer insulation, and avoid the risk of excessive losses caused by insulation damage after the electromagnetic components are packaged.

[0020] 2. The detection method proposed in this invention can be realized using a detection device consisting of an impact system control console, a high-voltage impact capacitor, a current sensing loop, a capacitive voltage divider, an insulation platform, and a test coil. It is simple, fast, and easy to operate, and is suitable for batch testing of iron cores.

[0021] 3. In the testing device proposed in this invention, a slot is opened inside the insulating platform. A flip plate, a first support element, and a telescopic block are arranged sequentially from top to bottom in the slot. During testing, the iron core to be tested is placed on the surface of the flip plate for testing. When the flip plate is not in use, the first support element is lowered by pushing the telescopic block down. The first support element is lowered with the telescopic block, so that the first support element is no longer held against the bottom of the flip plate. At this time, the flip plate is flipped along the second support element, which can effectively prevent dust and garbage from accumulating on the surface of the flip plate and extend the service life of the device. Attached Figure Description

[0022] Figure 1 A flowchart illustrating the method of Embodiment 1 of the present invention is provided;

[0023] Figure 2 A schematic diagram of the device is provided for Embodiment 2 of the present invention;

[0024] Figure 3 This is a schematic diagram of the insulating platform structure of the device in Embodiment 2 of the present invention;

[0025] Figure 4 This is a schematic cross-sectional view of the insulating platform structure of the device in Embodiment 2 of the present invention;

[0026] Figure 5 This is a schematic diagram of the insulation platform of the device in Embodiment 2 of the present invention from another perspective.

[0027] The components include: 1. Impact system control console; 2. High-voltage impact capacitor; 3. Current sensing ring; 4. Capacitive voltage divider; 5. Insulating platform; 6. Test coil; 7. Iron core under test; 501. Slot; 502. Flip plate; 503. First support element; 504. Telescopic block; 505. Second support element; 506. First handle; 507. Second handle; 508. Plug-in block; 509. Extension ring; 5081. Vibration plate; 5082. Extension block; 510. Spring; 5041. Base. Detailed Implementation

[0028] This invention provides a method and apparatus for detecting the interlayer insulation performance of an ultrathin silicon steel wound core. The method includes: step S1, simulating a high-voltage pulse; step S2, impacting the insulation layer of the core under test with the high-voltage pulse (the core under test is pre-acquired); step S3, acquiring the initial peak and trough currents of the core under test and calculating the corresponding positive-reverse current ratio; step S4, repeating steps S1 to S3 to acquire multiple positive-reverse current ratios; and step S5, determining that the interlayer insulation of the core under test is damaged when the change in the positive-reverse current ratio from the initial calculation to the final calculation meets a preset condition. The device is used to implement the various steps of the aforementioned method. The device includes an impact system control console, a high-voltage impact capacitor, a current sensing loop, a capacitive voltage divider, an insulating platform, and a test coil. The pre-acquired iron core to be tested is installed inside the test coil. The test coil is placed on the insulating platform, one end of which is connected to a high voltage and the other end is grounded. The test coil is connected to the high-voltage impact capacitor. A current sensing loop is sleeved on the connection line between the two. The interface end of the current sensing loop is connected to the impact system control console. The capacitive voltage divider is connected between the test coil and the impact system control console. The high-voltage impact capacitor is connected to the impact system control console.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the scope of protection of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides a method for testing the interlayer insulation performance of an ultra-thin silicon steel wound core. The specific process of implementing this method includes:

[0032] A test circuit was built using an existing high-voltage pulse simulation system, a high-voltage impulse capacitor, and a test coil. The ultra-thin silicon steel wound core to be tested was installed inside the test coil. The high-voltage pulse simulation system, the high-voltage impulse capacitor, and the test coil were connected in sequence, and the other end of the test coil was grounded.

[0033] Based on the established test circuit, a high-voltage pulse simulation system is used to simulate a high-voltage pulse and charge the high-voltage impulse capacitor. When the voltage in the circuit gradually increases to a preset threshold, a switch is automatically triggered, and the high-voltage impulse capacitor releases the high-voltage pulse, which is applied to the test coil. Under the action of the high-voltage pulse, the insulation layer in the iron core under test is subjected to the impulse voltage. By real-time monitoring and recording, the first peak current and trough current of the iron core under test are collected, and the corresponding positive and negative current ratios are calculated.

[0034] Repeat the aforementioned test process of simulating high-voltage pulse-impact on the insulation of the iron core under test and calculating the ratio of positive and negative currents. Perform at least two impact tests and compare the ratios of positive and negative currents between the first and last tests. When the ratio of positive and negative currents calculated in the last test is less than 95% of the ratio of positive and negative currents calculated in the first test, it is determined that the interlayer insulation of the iron core is damaged.

[0035] Example 2

[0036] like Figure 2As shown, this embodiment provides a testing device for the interlayer insulation performance of an ultra-thin silicon steel wound core, capable of implementing the method described in Embodiment 1. The device includes an impact system control console 1, a high-voltage impact capacitor 2, a current sensing loop 3, a capacitive voltage divider 4, an insulating platform 5, and a test coil 6. A pre-acquired core 7 is installed inside the test coil 6, which is placed on the insulating platform 5. One end of the insulating platform 5 is connected to a high voltage, and the other end is grounded. The test coil 6 is connected to the high-voltage impact capacitor 2, and a current sensing loop 3 is sleeved on the connecting wire between them. The interface end of the current sensing loop 3 is connected to the impact system control console 1. One end of the capacitive voltage divider 4 is connected to the test coil 6, and the other end is connected to the impact system control console 1. The high-voltage impact capacitor 2 is connected to the impact system control console 1, which also includes an oscilloscope. In the figure, the impact system control console 1, the high-voltage impact capacitor 2, and the test coil 6, connected in sequence, together constitute the test circuit.

[0037] Based on the established test circuit and test environment, the specific process for testing the interlayer insulation performance of ultra-thin silicon steel wound cores using a testing device is as follows:

[0038] (1) Place the test coil 6 on the insulating platform 5, connect one end to high voltage and the other end to ground wire. Install the iron core 7 to be tested on the test coil 6. After confirming that the wiring is good, set up a safety isolation zone and keep all personnel away from the test system isolation area.

[0039] (2) Control the impact system console 1 to set parameters to simulate high voltage pulse. After confirmation, the impact system console 1 will charge the high voltage impact capacitor 2 and store energy in the high voltage impact capacitor 2. After the voltage in the circuit gradually increases to the set parameters, the switch will be automatically triggered. The high voltage impact capacitor 2 will release the high voltage pulse and apply it to the test coil 6. Under the action of the high voltage pulse, the insulation layer in the iron core 7 under test will be impacted by the impact voltage.

[0040] (3) During the test, the capacitive voltage divider 4 and the current sensing ring 3 will monitor the voltage and current parameters on the iron core 7 under test and transmit them to the oscilloscope.

[0041] (4) The oscilloscope collects the first peak current and trough current of the iron core 7 under test, and calculates the ratio of the positive and negative currents.

[0042] (5) Repeat (2) to (4) and conduct 2 to 5 impact tests. Calculate the change in the ratio of positive to negative current between the first and last tests. When the result of the last calculation is less than 95% of the result of the first calculation, it can be determined that the interlayer insulation of the core 7 under test is damaged.

[0043] like Figures 3-5As shown, in this embodiment, the insulating platform 5 used in the device has a slot 501 inside. From top to bottom, a flip plate 502, a first support element 503 and a telescopic block 504 are arranged in the slot 501. The flip plate 502 and the telescopic block 504 are connected through the first support element 503.

[0044] A second support element 505 is provided on the side surface of the flip plate 502. The flip plate 502 is connected to the inner wall of the insulating platform 5 through the second support element 505. A first handle 506 is fixedly connected to the upper surface of the flip plate 502, and a second handle 507 is fixedly connected to the outer surface of the insulating platform 5. The second support element 505 is a rotating shaft, and two sets of rotating shafts are provided, so that the flip plate 502 can rotate along the rotating shafts.

[0045] The insulating platform 5 also includes a plug-in block 508 and an extension ring 509. The plug-in block 508 is plugged into the flip plate 502, and the extension ring 509 is fixedly connected to the inner wall of the insulating platform 5. Vibration plates 5081 are fixedly connected to both ends of the plug-in block 508, and the extension block 5082 is fixedly connected to its bottom. The diameter of the vibration plate 5081 is larger than the diameter of the plug-in block 508. An elastic element is fixedly connected to the bottom of the extension ring 509. The elastic element is a spring 510, which exerts a thrust on the telescopic block 504.

[0046] One end of the spring 510 is connected to the lower surface of the extension ring 509, and the other end is connected to the upper surface of the telescopic block 504. The telescopic block 504 is located inside the slot 501 and can move within the slot 501. A base 5041 is fixed to the bottom of the telescopic block 504. A first support element 503 is fixedly connected to the upper surface of the telescopic block 504. The first support element 503 is a support rod. Multiple sets of this support rod are provided, and its top rests against the bottom of the flip plate 502.

[0047] When using the aforementioned device for testing, the iron core 7 to be tested is placed on the flip plate 502 for testing and recording. When the flip plate 502 is not in use, a large amount of dust and debris will accumulate on its surface. By lifting the insulating platform 5 with the second handle 507, the telescopic block 504 is lowered under the push of the spring 510. The base 5041 is lowered with the telescopic block 504, and the first support element 503 is lowered with the telescopic block 504. The first support element 503 is no longer supported on the bottom of the flip plate 502. The flip plate 502 can be flipped along the rotating shaft by the first handle 506, which can prevent dust and debris from accumulating on the surface of the flip plate 502. The extension block 5082 drives the plug-in block 508 to move. During the movement, the plug-in block 508 can shake off the dust on the surface of the flip plate 502, and the vibrating plate 5081 plays a limiting role.

[0048] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for testing the interlayer insulation performance of an ultra-thin silicon steel wound core, characterized in that, The method Includes the following steps: S1 simulates a high-voltage pulse; S2, the high-voltage pulse is used to impact the insulation layer of the iron core under test, which is obtained in advance; S3, obtain the first peak current and trough current of the iron core under test, and calculate the corresponding positive and negative current ratio; S4, repeat S1~S3 to obtain multiple forward and reverse current ratios; S5, when the comparison result of the positive and negative current ratio of the last calculation and the first calculation meets the preset conditions, it is determined that the interlayer insulation of the iron core under test is damaged. The preset conditions include that the ratio of forward to reverse current in the last calculation is less than 95% of the ratio of forward to reverse current in the first calculation.

2. A testing device for the interlayer insulation performance of an ultra-thin silicon steel wound core, characterized in that, The device is used to implement the method as described in claim 1, and the device includes an impact system control console, a high-voltage impact capacitor, a current sensing loop, a capacitive voltage divider, an insulating platform, and a test coil. The pre-acquired iron core to be tested is installed inside the test coil. The test coil is placed on the insulating platform. One end of the insulating platform is connected to a high voltage, and the other end is grounded. The test coil is connected to the high-voltage impulse capacitor. A current sensing loop is sleeved on the connection line between the two. The interface end of the current sensing loop is connected to the impulse system control console. The capacitive voltage divider is connected between the test coil and the impulse system control console. The high-voltage impulse capacitor is connected to the impulse system control console.

3. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 2, characterized in that, The impact system control console also includes an oscilloscope.

4. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 2, characterized in that, The insulating platform has a slot inside, and a flip plate, a first support element, and a telescopic block are arranged in the slot from top to bottom. The flip plate and the telescopic block are connected through the first support element.

5. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 4, characterized in that, A second support element is provided on the side surface of the flip plate, and the flip plate is connected to the inner wall of the insulating platform through the second support element. A first handle is fixedly connected to the upper surface of the flip plate, and a second handle is fixedly connected to the outer surface of the insulating platform.

6. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 4, characterized in that, The insulating platform also includes a plug-in block and an extension ring. The plug-in block is plugged into the flip plate, and the extension ring is fixedly connected to the inner wall of the insulating platform.

7. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 6, characterized in that, Vibration plates are fixedly connected to both ends of the plug-in block, and an extension block is fixedly connected to the bottom.

8. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 6, characterized in that, The bottom of the extension ring is connected to a fixed elastic element.

9. The testing device for the interlayer insulation performance of ultra-thin silicon steel wound core according to claim 7, characterized in that, The diameter of the vibrating plate is larger than the diameter of the plug block.

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