Magnetic property testing system and method for applying local stress to an ultrathin magnetic material

Abstract

The application discloses a magnetic property testing system and a local stress applying method for an ultrathin strip magnetic material. The system comprises a measuring device, wherein the measuring device comprises four B coils, which are wound around four preset holes of a sample to be measured and are arranged in a mouth-shaped mode; MFC piezoelectric sheets, which are arranged at the center positions of two surfaces of the sample to be measured; strain gauges, which are arranged on the surfaces of the two MFC piezoelectric sheets away from the sample to be measured; TMR sensors, which are arranged at the center positions of the two MFC piezoelectric sheets away from the sample to be measured; each TMR sensor is arranged adjacent to the strain gauge on the same side of the TMR sensor; two PCB circuit boards are arranged in one-to-one correspondence with the two TMR sensors; a spacer is arranged between the PCB circuit board and the sample to be measured, and a receiving groove is formed in the spacer to receive the corresponding TMR sensor; and a control unit is connected with the measuring device and used for controlling the operation of the measuring device.

Description

Technical Field

[0001] This disclosure generally relates to the field of magnetic property measurement technology for samples under stress loading conditions, and specifically to magnetic property testing systems and methods for applying local stress to ultrathin magnetic materials. Background Technology

[0002] Among the various methods to reduce iron loss in grain-oriented silicon steel, reducing strip thickness is widely used due to its advantages. Therefore, ultra-thin magnetic strip materials are widely used in various electrical equipment. To meet the development needs of high-voltage and high-efficiency power grids, develop a new power system based on new energy sources, and promote efficient energy utilization, high-frequency transformers have replaced traditional transformers and become the core component of power electronic equipment. The core materials of high-frequency transformers mainly include new ultra-thin silicon steel and nanocrystalline and amorphous materials. The design of traditional high-frequency transformers often relies on alternating magnetic characteristic data measured under standard excitation, neglecting the influence of service conditions. Under stress conditions, the magnetic characteristics exhibited by the material differ significantly from those under standard sinusoidal excitation.

[0003] Previously, many researchers have studied the effects of mechanical stress on the magnetic properties of traditional electrical steel. In recent years, numerous universities and research institutions both domestically and internationally have conducted many tests on the magnetic properties of silicon steel. Unlike silicon steel, high-frequency magnetic materials are a new type of magnetic material, and current tests on these new materials are mostly conducted under standard sinusoidal conditions. High-frequency magnetic material strips are relatively thin (<0.03 mm), and some materials, such as nanocrystalline strips, exhibit low hardness and high brittleness after annealing, making it difficult to conduct magnetic property tests under stress conditions. Therefore, research on the magnetic properties of high-frequency magnetic materials under stress conditions is rarely reported.

[0004] Ultrathin grain-oriented electrical steel (GOES) with a thickness of less than 0.1 mm can be used to manufacture reactor cores and high-power magnetic amplifiers. The design of these electromagnetic devices typically relies on magnetic property data measured under standard sinusoidal excitation. However, the effects of operating conditions such as stress and temperature are neglected. The magnetic properties of magnetic materials under stress differ from those under sinusoidal excitation, which may affect the accuracy of core loss calculations. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a magnetic property testing system and a method for applying local stress to ultrathin magnetic strip materials that reduces the excitation difficulty and improves the testing accuracy under stress conditions.

[0006] In a first aspect, this application provides a magnetic property testing system, comprising:

[0007] Measuring device, the measuring device comprising:

[0008] There are four B coils, which are wound around the four preset holes of the sample being tested and arranged in a square shape.

[0009] Two MFC piezoelectric elements are used, and the two elements are respectively placed at the center positions of the two surfaces of the sample being tested.

[0010] Two strain gauges are provided, and each strain gauge is disposed on the surface of the two MFC piezoelectric sheets away from the sample being tested.

[0011] Two TMR sensors are provided, each positioned at the center of one of the two MFC piezoelectric plates away from the sample being tested; each TMR sensor is adjacent to a strain gauge on the same side.

[0012] The PCB circuit board is provided in two, and the two PCB circuit boards are electrically connected to the two TMR sensors respectively; a spacer is provided between the PCB circuit board and the sample under test, and the spacer is provided with a receiving groove for accommodating the corresponding TMR sensor.

[0013] A control unit, which is connected to the measuring device, is used to control the operation of the measuring device.

[0014] According to the technical solution provided in the embodiments of this application, the control unit includes: an MFC stress loading device;

[0015] The MFC stress loading device includes:

[0016] A DC voltage source, configured to provide DC voltage;

[0017] A high-voltage amplification module, wherein the input terminal of the high-voltage amplification module is connected to the DC voltage source and the output terminal is connected to the MFC piezoelectric element, and is configured to amplify the DC voltage and send it to the MFC piezoelectric element.

[0018] According to the technical solution provided in the embodiments of this application, the control unit further includes: a data acquisition unit;

[0019] The data acquisition unit includes:

[0020] An excitation device, which is connected to the sample under test, is configured to transmit an excitation signal to the sample under test;

[0021] An amplifier circuit module, the input terminals of which are electrically connected to the TMR sensor and the B coil respectively, is configured to amplify the B-induced voltage signal generated by the B coil and the H-induced voltage signal generated by the TMR sensor;

[0022] The acquisition module has its input terminal connected to the output terminal of the amplifier circuit module and is configured to transmit an excitation signal for the excitation device.

[0023] The acquisition module is also configured to acquire the amplified B-induced voltage signal and the amplified H-induced voltage signal;

[0024] A power amplifier module, which is connected to the acquisition module, is configured to amplify the signal transmitted by the acquisition module;

[0025] An isolation transformer module is provided, the output of which is connected to a power amplifier module and the excitation device. It is configured to suppress noise in the signal amplified by the power amplifier module.

[0026] According to the technical solution provided in the embodiments of this application, a control module is provided between the acquisition module and the MFC piezoelectric sheet, configured to convert the amplified B induced voltage signal and the amplified H induced voltage signal into B signal and H signal respectively;

[0027] The control module is also configured to control the voltage applied to the MFC piezoelectric element based on the excitation signal acquired by the acquisition module.

[0028] According to the technical solution provided in the embodiments of this application, the control unit further includes: a lock-in amplifier module, the input terminal of which is connected to the strain gauge, and its output terminal is connected to the acquisition module, configured to acquire the initial signal of the strain gauge and transmit it to the acquisition module.

[0029] According to the technical solution provided in the embodiments of this application, a high-power resistor is provided between the power amplifier module and the isolation transformer module.

[0030] According to the technical solution provided in the embodiments of this application, the TMR sensor is also connected to a power supply module, which is configured to supply power to the TMR sensor.

[0031] Secondly, this application provides a method for applying local stress to an ultrathin magnetic strip material, using the aforementioned magnetic property testing system. The method for applying local stress to the ultrathin magnetic strip material includes the following steps:

[0032] The initial DC voltage provided by the DC voltage source is amplified using a high-voltage amplifier module and transmitted to the MFC piezoelectric element.

[0033] The amplified initial DC voltage is transmitted to the strain gauge via the sample under test;

[0034] The initial signal of the strain gauge is acquired using a lock-in amplifier module;

[0035] The sample under test is initialized and calibrated based on the initial signal collected, and the H-induced voltage signal collected by the TMR sensor is determined.

[0036] The excitation signal output by the acquisition module is controlled by the control module, and the excitation signal is transmitted to the excitation device through the power amplifier module, the high-power resistor and the isolation transformer module.

[0037] The excitation device sends a set excitation signal to the sample under test, causing the B coil to generate a set B induced voltage signal and the TMR sensor to measure the set H induced voltage signal.

[0038] Adjust the DC voltage source to control the DC voltage data applied to the MFC piezoelectric element;

[0039] The magnetic property data of the sample under stress loading are acquired using the acquisition module;

[0040] The control module is used to observe the magnetic property data collected by the acquisition module.

[0041] In summary, this application specifically discloses the structure of a magnetic property testing system. This application designs a measuring device and a control unit for cooperative use. The measuring device includes: four B coils, each wound in one of the four preset holes of the sample under test in a U-shape; MFC piezoelectric plates are respectively positioned at the center of two surfaces of the sample under test; strain gauges and TMR sensors are respectively positioned on the surfaces of the two MFC piezoelectric plates away from the sample under test, with the TMR sensors located at the center of the MFC piezoelectric plates, and each TMR sensor and the strain gauge on the same side are arranged adjacent to each other; two PCB circuit boards are electrically connected to the two TMR sensors respectively, and a spacer with a receiving groove is provided between the PCB circuit boards and the sample under test for accommodating the corresponding TMR sensors.

[0042] The MFC piezoelectric element generates a B-induced voltage signal through four B coils. It applies uniform tensile or compressive stress to the sample under test and measures the strain of the sample using strain gauges. The H-induced voltage signal is then measured using a TMR sensor. The DC voltage applied to the MFC piezoelectric element is controlled by the control unit, which controls the magnitude of the MFC output force. After adjusting the output voltage, the magnetic properties of the sample under test can be acquired and observed under stress loading conditions. This achieves the goal of reducing excitation difficulty and improving test accuracy under stress conditions. Attached Figure Description

[0043] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0044] Figure 1This is a front view schematic diagram of the measuring device.

[0045] Figure 2 This is a schematic diagram of the measuring device.

[0046] Figure 3 This is a schematic diagram of the structure of the MFC piezoelectric element and the sample under test.

[0047] Figure 4 This is a schematic diagram of the magnetic property testing system.

[0048] Figure 5 This is a schematic diagram of a magnetic property testing system.

[0049] Labels in the diagram: 1. Sample under test; 2. B coil; 3. MFC piezoelectric element; 4. Strain gauge; 5. TMR sensor; 6. PCB circuit board; 7. Spacer; 8. Power supply module; 9. MFC stress loading device; 10. DC voltage source; 11. High voltage amplification module; 12. Excitation device; 13. Amplification circuit module; 14. Acquisition module; 15. Power amplification module; 16. Isolation transformer module; 17. Control module; 18. Phase-locked loop amplification module; 19. High-power resistor. Detailed Implementation

[0050] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] Example 1

[0053] Please refer to Figure 1 and Figure 2 The schematic diagram shown below illustrates a first embodiment of a magnetic property testing system provided in this application, comprising:

[0054] Measuring device, the measuring device comprising:

[0055] There are four B coils 2, which are wound around the four preset holes of the sample 1 and arranged in a square shape.

[0056] The MFC piezoelectric element 3 consists of two pieces, which are respectively positioned at the center of the two surfaces of the sample 1 under test;

[0057] Two strain gauges 4 are provided, and they are respectively disposed on the surfaces of the two MFC piezoelectric sheets 3 away from the sample 1 being tested.

[0058] There are two TMR sensors 5, and they are respectively located at the center of the two MFC piezoelectric sheets 3 on the side away from the sample 1 being tested; each TMR sensor 5 is arranged adjacent to the strain gauge 4 on the same side;

[0059] There are two PCB circuit boards 6, and the two PCB circuit boards 6 are electrically connected to the two TMR sensors 5 respectively. A spacer 7 is provided between the PCB circuit board 6 and the sample 1 under test. The spacer 7 has a receiving groove for accommodating the corresponding TMR sensor 5.

[0060] A control unit, which is connected to the measuring device, is used to control the operation of the measuring device.

[0061] In this embodiment, the sample 1 to be tested can be an ultra-thin magnetic material, such as an ultra-thin oriented electrical steel with a side length of 50 mm and a thickness of 0.1 mm; wherein, the sample 1 to be tested has four preset holes for winding the B coil 2; the diameter of the preset holes can be 1 mm, and the straight-line distance between adjacent preset holes can be 14 mm;

[0062] Measuring device, comprising:

[0063] Four B coils 2 are used to generate the B induced voltage signal; the four B coils 2 are respectively wound around the four preset holes of the sample 1 under test, and the four B coils 2 are arranged in a square shape, as shown below. Figure 3 As shown, a single-turn winding passes through two adjacent preset holes to form a B coil 2. By passing four single-turn windings through two adjacent preset holes respectively, four B coils 2 are formed.

[0064] Two MFC piezoelectric elements 3 are used, one on the upper surface and the other on the lower surface of the sample 1. The MFC piezoelectric elements 3 are used to apply uniform tensile or compressive stress to the sample 1. By using different types of MFC piezoelectric elements 3, tensile or compressive stress can be applied. When the type of MFC piezoelectric element 3 is P1, the force applied to the sample 1 is tensile stress. When the type of MFC piezoelectric element 3 is P2, the force applied to the sample 1 is compressive stress.

[0065] The connection method between the MFC piezoelectric sheet 3 and the surface of the sample 1 can be, for example, by using DP460 glue to attach two MFC piezoelectric sheets 3 to the center positions of the upper and lower surfaces of the sample 1, and then pressing them with a heavy object at room temperature for about 5 hours to firmly attach the MFC piezoelectric sheet 3 to the surface of the sample 1, and the two MFC piezoelectric sheets 3 are set perpendicular to each other after being attached.

[0066] Here, the material of the MFC piezoelectric element 3 is a piezoelectric material, such as a macrofiber composite material, which can apply large and uniform local stress. Taking the M2814-P1 type MFC piezoelectric element 3 as an example, its dimensions are 28mm in length and 14mm in width, its maximum DC voltage is 1500V, and its maximum output tensile stress is approximately 146N.

[0067] Two strain gauges 4 are respectively placed on the surfaces of two MFC piezoelectric plates 3 away from the sample 1 to measure the strain of the sample 1. The strain is determined by measuring the change in resistance, and the stress can be calculated by multiplying the measured strain by the Young's modulus of the ultrathin GOES.

[0068] The connection method between the strain gauge 4 and the MFC piezoelectric element 3 is, for example, an adhesive connection; the size of the strain gauge 4 can be 3mm × 4mm.

[0069] There are two TMR sensors 5, which are respectively set at the center of the two MFC piezoelectric plates 3 on the side away from the sample 1. Each TMR sensor 5 and the strain gauge 4 on the same side are arranged adjacent to each other to measure the H-induced voltage signal.

[0070] The TMR sensor 5 features high sensitivity and signal-to-noise ratio. Compared to traditional H-coils, the TMR does not require close contact with the sample surface to measure the H-induced voltage signal. The TMR sensor 5 can be a tunnel magnetoresistive sensor chip, such as the TMR2602 (5mm × 6mm), which requires a 4.8–5.5V DC drive. Both TMR sensors 5 are perpendicular to each other, with their long sides aligned with the long side of the MFC piezoelectric element 3. For example, if the long side of the MFC piezoelectric element 3 on the upper surface of the sample 1 is aligned along the x-axis, then the long side of the TMR sensor 5 on it is also aligned along the x-axis. Both the B-coil 2 and the TMR sensor 5 use twisted-pair wiring.

[0071] Two PCB circuit boards 6 are provided, each electrically connected to one of the two TMR sensors 5. A spacer 7 is provided between the PCB circuit boards 6 and the sample 1 under test. The spacer 7 has a receiving groove to accommodate the corresponding TMR sensor 5. The PCB circuit boards 6 and the spacer 7 cooperate to fix the sample 1 under test, ensuring that the sample 1 remains flat in its initial state and is not subject to external forces caused by bending or deformation. The PCB circuit board 6 can be a Hongwenda 9989 circuit board.

[0072] PCB board 6 has VDD, GND and Vout. VDD is connected to the positive terminal of power supply module 8 to reduce ripple interference. GND is connected to power supply module 8 to drive TMR sensor 5. Vout and GND are connected to twisted pair to output the measured H induced voltage signal. TMR sensor 5 has 8 pins, all of which are soldered on PCB board 6.

[0073] The measuring device generates a B-induced voltage signal by winding four B coils 2 around the sample 1 under test. MFC piezoelectric elements 3 are respectively placed at the center positions of the upper and lower surfaces of the sample 1 to apply uniform tensile or compressive stress to the sample 1. The strain of the sample 1 is measured by a strain gauge 4 on the surface of the MFC piezoelectric element 3 away from the sample 1. The H-induced voltage signal is measured by a TMR sensor 5 at the center position of the side of the MFC piezoelectric element 3 away from the sample 1. The DC voltage applied to the MFC piezoelectric element 3 is controlled by the control unit to control the magnitude of the MFC output force. After adjusting the output voltage, the magnetic properties of the sample under stress loading conditions can be collected and observed, thereby reducing the excitation difficulty and improving the test accuracy under stress conditions.

[0074] Furthermore, such as Figure 4 As shown, the control unit includes: MFC stress loading device 9;

[0075] The MFC stress loading device 9 includes:

[0076] A DC voltage source 10 is configured to provide a DC voltage; here, the type of DC voltage source 10 is, for example, a JK-K series regulated power supply; the magnitude of the output force of the piezoelectric element 3 is controlled by controlling the DC voltage applied to the MFC piezoelectric element 3;

[0077] The high-voltage amplification module 11 has its input terminal connected to the DC voltage source 10 and its output terminal connected to the MFC piezoelectric element 3. It is configured to amplify the DC voltage and send it to the MFC piezoelectric element 3. By controlling the on / off state of the MFC piezoelectric element 3 and the high-voltage amplification module 11, the loading of uniaxial and biaxial stresses on the sample 1 under test is controlled. Here, the type of the high-voltage amplification module 11 is, for example, a high-voltage amplifier, and its model is, for example, ATA-2021H.

[0078] Furthermore, it also includes: a data acquisition unit;

[0079] The data acquisition unit includes:

[0080] An excitation device 12 is connected to the sample 1 under test and is configured to transmit an excitation signal to the sample 1 under test. Here, the type of excitation device 12 is, for example, an excitation winding. By switching on different excitation windings, the sample 1 under test can be magnetized in one dimension or in two dimensions.

[0081] The amplifier circuit module 13 has its input terminals electrically connected to the TMR sensor 5 and the B coil 2, respectively, and is configured to amplify the B-induced voltage signal generated by the B coil 2 and the H-induced voltage signal generated by the TMR sensor 5; here, the type of amplifier circuit module 13 is, for example, an amplifier circuit.

[0082] The acquisition module 14 has its input terminal connected to the output terminal of the amplifier circuit module 13 and is configured to transmit the excitation signal from the excitation device 12; here, the acquisition module 14 is, for example, a data acquisition card;

[0083] The acquisition module 14 is also configured to acquire the amplified B-induced voltage signal and the amplified H-induced voltage signal;

[0084] A power amplifier module 15 is connected to the acquisition module 14 and is configured to amplify the signal transmitted by the acquisition module 14; here, the power amplifier module 15 is, for example, a power amplifier, and its model is, for example, ATA2021H.

[0085] The isolation transformer module 16 is connected to the power amplifier module 15 at its output terminal and to the excitation device 12 at its output terminal. It is configured to suppress noise in the signal amplified by the power amplifier module 15. Here, the type of the isolation transformer module 16 is, for example, an isolation transformer, and its model is, for example, an SG-40KVA three-phase isolation transformer.

[0086] Furthermore, a control module 17 is provided between the acquisition module 14 and the MFC piezoelectric sheet 3, configured to convert the amplified B induced voltage signal and the amplified H induced voltage signal into B signal and H signal respectively;

[0087] The control module 17 is also configured to control the voltage applied to the MFC piezoelectric sheet 3 according to the excitation signal acquired by the acquisition module 14; here, the control module 17 may be a computer with LabVIEW.

[0088] Furthermore, it also includes: a lock-in amplifier module 18, the input terminal of which is connected to the strain gauge 4, and its output terminal is connected to the acquisition module 14, configured to acquire the initial signal of the strain gauge 4 and transmit it to the acquisition module 14; here, the type of the lock-in amplifier module 18 is, for example, a lock-in amplifier, and its model is, for example, SR830.

[0089] Furthermore, a high-power resistor 19 is provided between the power amplifier module 15 and the isolation transformer module 16 to protect the circuit.

[0090] Furthermore, the TMR sensor 5 is also connected to a power supply module 8, configured to power the TMR sensor 5 and reduce ripple interference; here, the power supply module 8 may be a battery box containing a power supply battery.

[0091] Example 2

[0092] A method for applying local stress to an ultrathin magnetic material, using a magnetic property testing system as described in Example 1, includes the following steps:

[0093] The initial DC voltage provided by the DC voltage source 10 is amplified by the high voltage amplification module 11 and transmitted to the MFC piezoelectric element 3.

[0094] The amplified initial DC voltage is transmitted to strain gauge 4 via the sample under test 1;

[0095] The initial signal of strain gauge 4 is acquired using lock-in amplifier module 18;

[0096] The sample 1 under test is initialized and calibrated based on the initial signal collected, and the H-induced voltage signal collected by the TMR sensor 5 is determined.

[0097] The excitation signal output by the acquisition module 14 is controlled by the control module 17, and the excitation signal is transmitted to the excitation device 12 via the power amplifier module 15, the high-power resistor 19 and the isolation transformer module 16.

[0098] The excitation device 12 sends a set excitation signal to the sample 1 under test, causing the B coil 2 to generate a set B induced voltage signal and the TMR sensor 5 to measure the set H induced voltage signal.

[0099] Adjust the DC voltage source 10 to control the DC voltage applied to the MFC piezoelectric element 3;

[0100] The magnetic property data of the sample 1 under stress loading are acquired using the acquisition module 14.

[0101] The magnetic property data acquired by the acquisition module 14 are observed using the control module 17.

[0102] In this embodiment, taking the tested sample 1 as an example, which is an ultra-thin oriented electrical steel with a side length of 50 mm and a thickness of 0.1 mm, an xy coordinate system is established, and... Figure 3 The horizontal direction is defined as the x-direction of the coordinate system, and the vertical direction is defined as the y-direction of the coordinate system. The x-direction and the y-direction intersect at the center of the sample 1 being tested, which is the origin of the coordinate system.

[0103] Two MFC piezoelectric sheets 3 are glued perpendicularly to each other to the center of the upper and lower surfaces of the sample 1 to be tested, and then pressed with a heavy object at room temperature for about 5 hours to make the MFC piezoelectric sheets 3 firmly attached to the surface of the sample 1 to be tested. Then, two strain gauges 4 are glued to the back of the area covered by the MFC piezoelectric sheets 3 along the x and y directions respectively.

[0104] Four holes are drilled at the four intersection points of the two MFC piezoelectric sheets 3 on the sample 1 to obtain four preset holes. Four single-turn windings are passed through the holes to form four B coils 2.

[0105] The TMR sensor 5 is soldered onto the PCB circuit board 6, and the power supply module 8 is used to drive the TMR sensor 5.

[0106] Connect the output terminal of the DC voltage source 10 to the high voltage amplifier module 11, and weld the output terminal of the high voltage amplifier module to the positive and negative terminals of the MFC piezoelectric element 3.

[0107] Connect the twisted pair output line of the measuring device to the interface of the amplifier circuit module 13, and connect the output terminal of the amplifier circuit module 13 to the corresponding input terminal of the acquisition module 14. The acquisition module 14 is connected to the control module 17, and the acquisition module 14 communicates bidirectionally with the control module 17. At the same time, the acquisition module 14 is connected to the power amplifier module 15, and then connected to the isolation transformer module 16 through the high-power resistor 19 and connected to the excitation device 12. Then, connect the output lead of the strain gauge 4 to the input terminal of the acquisition module 14 through the phase-locked amplifier module 18.

[0108] The B-induced voltage signal and the H-induced voltage signal are amplified by the amplifier circuit module 13 and then acquired by the acquisition module 14. They are then processed into B and H signals by the control module 17. After checking that there are no problems with the circuit connection, the output signal of the strain gauge 4 is acquired.

[0109] Power amplifier module 15 is turned on. Control module 17 controls the frequency of the excitation signal output from acquisition module 14 and the peak value of excitation signal B. DC voltage source 10 and high-voltage amplifier module 11 are switched on. By adjusting the output voltage of DC voltage source 10, the DC voltage applied to MFC piezoelectric element 3 is controlled, thereby controlling the output force of MFC piezoelectric element 3. By controlling the connection between MFC piezoelectric element 3 and high-voltage amplifier module 11, uniaxial and biaxial stress loading can be applied to the test sample 1. By using different types of MFC piezoelectric elements 3, tensile or compressive stress loading can be achieved. By connecting different excitation devices 12, the test sample 1 can be magnetized one-dimensionally or two-dimensionally. After adjusting the output voltage of DC voltage source 10, control module 17 can be used to observe and acquire data on the magnetic characteristics of the test sample 1 under stress loading.

[0110] Furthermore, before the test begins, the lock-in amplifier module 18 acquires the signal from strain gauge 4. Based on the acquired signal, the sample 1 under test is initialized and calibrated, and the signal parameters acquired by the TMR sensor 5 and the magnitude of the actual stress output by the MFC piezoelectric element 3 are determined. The measured H signal parameters are then input to the control module 17. Here, the measured H signal is, for example, 9.966658331875019e-04. The PCB circuit board 6 and spacers 7 are used to fix the sample 1 under test on the upper and lower layers to ensure that the sample is flat in its initial state and is not subject to external forces caused by bending or deformation.

[0111] Among them, setting Figure 3 The two B coils 2, one above the other, are considered as a group. The average of the measurements from the two B coils 2 yields the magnetic flux density B in the y-direction at the center of the sample 1, i.e., B0. y If we define the two B coils 2 in the diagram as a group, then by averaging the measurements from the two B coils 2, we can obtain the magnetic flux density B in the x-direction at the center position of the sample 1 being measured, i.e., B0. x .

[0112] The induced voltage on coil B is measured, amplified by an amplifier board, and then input to a data acquisition card. The magnetic flux density B is then calculated using the LabVIEW program on a computer. B can be calculated using the following formula:

[0113]

[0114] Where N is the number of turns of coil B; S is the cross-sectional area of ​​coil B; V B This is the induced voltage signal generated in coil B.

[0115] The induced voltage on TMR sensor 5 is measured, amplified by an amplifier board, and then input to the data acquisition card. The magnetic field strength H is then calculated using the LabVIEW program on a computer. H can be calculated using the following formula:

[0116]

[0117] Where E is the measured value of the induced voltage, and k1 is the coefficient after the H signal is calibrated.

[0118] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A magnetic property testing system, characterized in that, include: Measuring device, the measuring device comprising: There are four B coils (2), which are wound in four preset holes of the sample (1) and arranged in a square shape. Two MFC piezoelectric sheets (3) are respectively placed at the center of the two surfaces of the sample under test (1); the two MFC piezoelectric sheets (3) are perpendicularly attached to the center of the upper and lower surfaces of the sample under test (1), and holes are drilled at the four intersection points of the two MFC piezoelectric sheets (3) on the sample under test (1) to obtain four preset holes. Two strain gauges (4) are provided, and they are respectively placed on the surfaces of the two MFC piezoelectric sheets (3) away from the sample (1) being tested. Two TMR sensors (5) are provided, and they are respectively located at the center of the two MFC piezoelectric plates (3) on the side away from the sample (1) being measured; each TMR sensor (5) is arranged adjacent to a strain gauge (4) on the same side thereon. There are two PCB circuit boards (6), and the two PCB circuit boards (6) are electrically connected to the two TMR sensors (5) respectively. A spacer (7) is provided between the PCB circuit board (6) and the sample (1) under test. The spacer (7) has a receiving groove for accommodating the corresponding TMR sensor (5). A control unit, which is connected to the measuring device, is used to control the operation of the measuring device.

2. The magnetic property testing system according to claim 1, characterized in that, The control unit includes: MFC stress loading device (9). The MFC stress loading device (9) includes: A DC voltage source (10) is configured to provide a DC voltage; A high voltage amplification module (11) is configured to amplify the DC voltage and transmit it to the MFC piezoelectric element (3). The input terminal of the high voltage amplification module (11) is connected to the DC voltage source (10), and its output terminal is connected to the MFC piezoelectric element (3).

3. The magnetic property testing system according to claim 1, characterized in that, The control unit further includes: a data acquisition unit; The data acquisition unit includes: An excitation device (12) is connected to the sample under test (1) and is configured to transmit an excitation signal to the sample under test (1); The amplifier circuit module (13) has its input terminals electrically connected to the TMR sensor (5) and the B coil (2) respectively, and is configured to amplify the B-induced voltage signal generated by the B coil (2) and the H-induced voltage signal generated by the TMR sensor (5); The acquisition module (14) has its input terminal connected to the output terminal of the amplifier circuit module (13) and is configured to transmit the excitation signal for the excitation device (12); The acquisition module (14) is also configured to acquire the amplified B-induced voltage signal and the amplified H-induced voltage signal; A power amplifier module (15) is connected to the acquisition module (14) and configured to amplify the signal transmitted by the acquisition module (14); An isolation transformer module (16) is connected to a power amplifier module (15) at its output end and to an excitation device (12) at its output end. It is configured to suppress noise in the signal amplified by the power amplifier module (15).

4. The magnetic property testing system according to claim 3, characterized in that, A control module (17) is provided between the acquisition module (14) and the MFC piezoelectric sheet (3), which is configured to convert the amplified B induced voltage signal and the amplified H induced voltage signal into B signal and H signal respectively; The control module (17) is also configured to control the voltage applied to the MFC piezoelectric sheet (3) based on the excitation signal acquired by the acquisition module (14).

5. A magnetic property testing system according to claim 3 or 4, characterized in that, The control unit further includes a lock-in amplifier module (18), the input end of which is connected to the strain gauge (4), and its output end is connected to the acquisition module (14), configured to acquire the initial signal of the strain gauge (4) and transmit it to the acquisition module (14).

6. The magnetic property testing system according to claim 3, characterized in that, A high-power resistor (19) is provided between the power amplifier module (15) and the isolation transformer module (16).

7. The magnetic property testing system according to claim 1, characterized in that, The TMR sensor (5) is also connected to a power supply module (8), which is configured to supply power to the TMR sensor (5).

8. A method for applying localized stress to an ultrathin magnetic material, characterized in that, Using the magnetic property testing system according to any one of claims 1 to 7, the method for applying local stress to the ultrathin magnetic strip material includes the following steps: The initial DC voltage provided by the DC voltage source (10) is amplified by the high voltage amplification module (11) and transmitted to the MFC piezoelectric element (3). The amplified initial DC voltage is transmitted to the strain gauge (4) via the sample under test (1); The initial signal of the strain gauge (4) is acquired using the lock-in amplifier module (18); The sample (1) under test is initialized and calibrated according to the initial signal collected, and the H-induced voltage signal collected by the TMR sensor (5) is determined. The excitation signal output by the acquisition module (14) is controlled by the control module (17), and the excitation signal is transmitted to the excitation device (12) via the power amplifier module (15), the high-power resistor (19) and the isolation transformer module (16). The excitation device (12) sends a set excitation signal to the sample (1) to be tested, so that the B coil (2) generates a set B induced voltage signal and the TMR sensor (5) measures the set H induced voltage signal. Adjust the DC voltage source (10) to control the DC voltage data applied to the MFC piezoelectric sheet (3); The magnetic properties data of the sample under test (1) under stress loading were acquired using the acquisition module (14); The magnetic property data acquired by the acquisition module (14) is observed using the control module (17).

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