A magnetoelectric composite magnetic sensitive device with differential structure

Abstract

The present invention discloses a magneto-electric composite magnetic sensitive device with a differential structure, wherein a measuring device, a compensating device, and a magnetic shielding layer are installed in a device bracket; the measuring device is located above the magnet to be measured, and the length direction of the measuring device is parallel to the magnetic field direction of the magnet to be measured, and is used to measure the magnitude of the magnetic field of the magnet to be measured; the compensating device is placed orthogonally to the measuring device, and the magnetic shielding layer is provided at the bottom of the measuring device to shield the magnetic field of the magnet to be measured parallel to the length direction of the compensating device, so as to collect the magnitude of the spatial background magnetic field. Advantages: The present invention designs an orthogonally placed measuring device and compensating device, and utilizes the directionality of the magnetic field to be measured and the non-directionality of the background magnetic field, as well as the anisotropy of the device, so that the compensating device is as insensitive to the magnetic field to be measured as possible, and is only sensitive to the background magnetic field. Therefore, the magnetic field to be measured is calculated using the difference between the outputs of the measuring device and the compensating device, and the influence of the background magnetic field on measurement and calibration is automatically compensated.

Description

Technical Field

[0001] The invention relates to a magneto-electric composite magnetic sensitive device with a differential structure, belonging to the technical field of magnetic sensors and current detection. Background Art

[0002] In recent years, with the continuous development of new functional materials such as ferromagnetic, ferroelectric, and ferroelastic materials, magnetoelectric composite materials based on magnetostrictive and piezoelectric materials have emerged. These materials utilize the magnetoelectric effect, a coupling effect between the magnetostrictive and piezoelectric effects, to detect magnetic fields. Due to their unique operating principles and structural composition, magnetoelectric sensors based on magnetoelectric composite materials are expected to meet the comprehensive performance requirements of many important applications, including high sensitivity, low power consumption, miniaturization, a wide range, low cost, room temperature operation, and vector detection. As mentioned earlier, the essence of non-contact current measurement is to measure the magnetic field generated by the current. Therefore, this new type of magnetic field sensor provides a new approach to current detection.

[0003] However, in actual use, especially in environments with strong current and high voltage, measuring weak currents will face great interference from the on-site background magnetic field. Solutions include magnetic shielding, magnetic field calibration and differential structure. Magnetic shielding achieves accurate measurement by shielding the background magnetic field, but in order to achieve a better shielding effect, the volume and weight of the magnetic shield are large, the material cost is high, and the magnetic shielding cannot completely shield all background magnetic fields; on-site magnetic field calibration eliminates the influence of the background magnetic field through the background magnetic field measurement parameters measured in advance, which is only suitable for occasions where the background magnetic field changes little. It cannot be applied in scenarios with large current changes such as substations. The differential structure eliminates the influence of the background magnetic field through the difference of the sensor, but the general differential structure will cause a significant decrease in sensitivity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a magneto-electric composite magnetic sensitive device with a differential structure.

[0005] In order to solve the above technical problems, the present invention provides a magneto-electric composite magnetic sensitive device with a differential structure, characterized in that it includes: a measuring device, a compensation device, a device bracket and a magnetic shielding layer;

[0006] Wherein, the measuring device, the compensating device and the magnetic shielding layer are installed in the device bracket;

[0007] The measuring device is located above the magnet to be measured, and the length direction of the measuring device is parallel to the magnetic field direction of the magnet to be measured, and is used to measure the magnetic field size of the magnet to be measured;

[0008] The compensation device is placed orthogonally to the measuring device, and the magnetic shielding layer is provided at the bottom of the measuring device to shield the magnetic field of the magnet to be measured parallel to the length direction of the compensation device, so as to collect the size of the spatial background magnetic field;

[0009] The final magnetic field magnitude of the magnet to be measured is obtained by subtracting the acquired spatial background magnetic field magnitude from the measured magnetic field magnitude of the magnet to be measured.

[0010] Furthermore, it also includes:

[0011] The magnetic shielding layer is installed in the device support and is located below the compensation device.

[0012] Furthermore, the measuring device includes: a measuring piezoelectric body, a measuring electrode and a measuring magnetostrictive film, wherein the measuring electrodes and the measuring magnetostrictive film are sequentially arranged outwardly on both sides of the measuring piezoelectric body.

[0013] Furthermore, the measuring electrode and the measuring piezoelectric body, and the measuring magnetostrictive film and the measuring electrode are mechanically connected respectively.

[0014] Furthermore, the compensation device includes: a compensating piezoelectric body, a compensating electrode and a compensating magnetostrictive film, wherein the compensating electrodes and the compensating magnetostrictive film are sequentially arranged outwardly on both sides of the compensating piezoelectric body.

[0015] Furthermore, the compensation electrode and the compensation piezoelectric body, and the compensation magnetostrictive film and the compensation electrode are mechanically connected respectively.

[0016] Furthermore, the measuring piezoelectric body and the compensating piezoelectric body have the same geometric dimensions and materials, the measuring electrode and the compensating electrode have the same geometric dimensions and materials, and the measuring magnetostrictive film and the compensating magnetostrictive film have the same geometric dimensions and materials.

[0017] Furthermore, the device bracket includes: a measuring device mounting groove and a compensating device mounting groove, wherein the depth of the measuring device mounting groove is deeper than the depth of the compensating device mounting groove.

[0018] Furthermore, the magnetic shielding layer is provided at the bottom of the compensation device installation groove.

[0019] Furthermore, the measuring device, the compensating device, and the magnetic shielding layer are all mechanically connected to the device bracket.

[0020] The beneficial effects achieved by the present invention are:

[0021] The present invention designs orthogonally placed measuring devices and compensating devices, and utilizes the directionality of the magnetic field to be measured, the non-directionality of the background magnetic field, and the anisotropy of the devices to make the compensating device as insensitive to the magnetic field to be measured as possible and only sensitive to the background magnetic field. The magnetic field to be measured is calculated using the difference between the outputs of the measuring device and the compensating device, automatically compensating for the influence of the background magnetic field on measurement and calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of the magneto-electric composite magnetic sensitive device with a differential structure according to the present invention;

[0023] Figure 2 This is a schematic structural diagram of the measuring device and the compensating device of the magneto-electric composite magnetic sensitive device with a differential structure according to the present invention;

[0024] Figure 3 This is a schematic structural diagram of a compensation device for the magneto-electric composite magnetic sensitive device with a differential structure according to the present invention;

[0025] Figure 4 This is a schematic structural diagram of a device support of a magneto-electric composite magnetic sensitive device with a differential structure according to the present invention;

[0026] In the figure: 1 is a measuring sensitive device; 11 is a measuring device piezoelectric body; 12 is a measuring device electrode; 13 is a measuring device magnetostrictive film; 2 is a compensation device; 21 is a compensating device piezoelectric body; 22 is a compensating device electrode; 23 is a compensating device magnetostrictive film; 3 is a device bracket; 31 is a measuring device mounting slot; 32 is a compensating device mounting slot; 4 is a magnetic shielding layer; 5 is a magnet to be measured. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] like Figure 1As shown, the present invention provides a differential structure magneto-electric composite magnetic sensitive device, comprising: a measuring device 1, a compensating device 2, and a device bracket 3; wherein the measuring device 1 and the compensating device 2 are installed in the device bracket 3 and mechanically connected to the device bracket 3, and the measuring device 1 and the compensating device 2 are placed orthogonally; the sensitivity of the measuring device 1 and the compensating device 2 to the magnetic field direction is the highest when parallel to the length direction of the measuring device 1 and the length direction of the compensating device 2, and the sensitivity is lower in other directions, so that the length direction of the measuring device 1 is parallel to the magnetic field direction of the magnet to be measured 5, and the magnetic field size of the magnet to be measured 5 can be measured with the highest sensitivity, and the length direction of the orthogonally placed compensating device 2 is perpendicular to the magnetic field direction of the magnet to be measured 5, so that the magnetic field collected by the compensating device 2 can minimize the magnetic field interference of the magnet to be measured 5. In addition, a shielding layer 4 is provided below the compensating device 2 to further eliminate the magnetic field interference of the magnet to be measured 5.

[0029] like Figure 4 As shown, the device bracket 3 includes a measuring device mounting groove 31 and a compensating device mounting groove 32, wherein the depth of the measuring device mounting groove 31 is deeper than the depth of the compensating device mounting groove 32; the present invention uses different mounting groove depths to make the compensating device further away from the magnetic field to be measured than the measuring device, thereby reducing the sensitivity of the compensating device to the magnetic field to be measured, improving the output sensitivity of the differential structure, and improving the practicality of the present invention.

[0030] like Figure 1 and 4 As shown, there is a magnetic shielding layer 4 at the bottom of the compensation device mounting groove 32, and the compensation device 2 is above the magnetic shielding layer 4; the design of the present invention also provides a magnetic shielding layer at the bottom of the compensation device mounting groove, which further reduces the sensitivity of the compensation device to the magnetic field to be measured and improves the practicality of the present invention.

[0031] like Figure 2 As shown, the measuring device 1 includes a measuring piezoelectric element 11, a measuring electrode 12, and a measuring magnetostrictive film 13. The measuring electrodes 12 are located on both sides of the measuring piezoelectric element 11, and the measuring magnetostrictive film 13 is located on both sides of the measuring electrode 12. The measuring electrodes 12 and the measuring piezoelectric element 11, and the measuring magnetostrictive film 13 and the measuring electrodes 12 are mechanically connected, respectively. In this embodiment, the measuring piezoelectric element 11 is made of a lead magnesium niobate single crystal, the measuring electrode 12 is made of a titanium-aluminum composite film, and the measuring magnetostrictive film 13 is made of a metglas amorphous alloy. By providing and measuring the magnetostrictive films on both sides of the measuring piezoelectric element, the mechanical deformation of the measuring piezoelectric element under the same alternating magnetic field is doubled, thereby improving the sensitivity of the device.

[0032] like Figure 3As shown, the compensation device 2 includes a compensating piezoelectric body 21, a compensating electrode 22, and a compensating magnetostrictive film 23. The compensating electrodes 22 are located on both sides of the compensating piezoelectric body 21, and the compensating magnetostrictive film 23 is located on both sides of the compensating electrode 22. The compensating electrode 22 and the compensating piezoelectric body 21 are mechanically connected, and the compensating magnetostrictive film 23 and the compensating electrode 22 are mechanically connected, respectively. In this embodiment, the compensating piezoelectric body 21 is made of lead magnesium niobate single crystal, the compensating electrode 22 is made of titanium-aluminum composite film, and the compensating magnetostrictive film 23 is made of metglas amorphous alloy. By providing the compensating magnetostrictive films on both sides of the compensating piezoelectric body, its mechanical deformation under the same alternating magnetic field is doubled, thereby improving the sensitivity of the device.

[0033] The measuring piezoelectric element 11 and the compensating piezoelectric element 21 have the same geometric dimensions and materials, the measuring electrode 12 and the compensating electrode 22 have the same geometric dimensions and materials, and the measuring magnetostrictive film 13 and the compensating magnetostrictive film 23 have the same geometric dimensions and materials. This ensures that the measuring device 1 and the compensating device 2 have exactly the same physical and material parameters, and therefore have consistent magnetic field measurement sensitivity. This ensures that the measuring device 1 and the compensating device 2 measure the same value of the spatial background magnetic field at the same time, thereby compensating for the influence of the spatial background magnetic field on the measurement.

[0034] The working principle of the differential structure magnetoelectric composite magnetic sensitive device of the present invention is:

[0035] Measuring device 1 is used to measure the magnetic field of the magnet under test 5. Since the magnetic field magnitude obtained by the measuring device equals the magnitude of the magnetic field under test + the magnitude of the spatial background magnetic field, the influence of the spatial background magnetic field needs to be removed. Therefore, compensation device 2 is introduced to compensate for the influence of the spatial background magnetic field. The measured magnetic field value is obtained by subtracting the magnetic field value measured by the compensation device from the magnetic field measured by the measuring device. To achieve this effect, the measuring device and compensation device have exactly the same physical geometric parameters and material composition, ensuring that the spatial background magnetic field values ​​measured at the same time are consistent.

[0036] Since the compensation device 2 may also detect a portion of the magnetic field to be measured, this will cause the detection sensitivity of the device to decrease. Therefore, in order to further improve the compensation effect, it is necessary to minimize the magnetic field to be measured by the compensation device 2. This can be achieved through the following two methods:

[0037] 1. The device bracket 3 includes a measuring device mounting groove 31 and a compensating device mounting groove 32, wherein the depth of the measuring device mounting groove 31 is deeper than the depth of the compensating device mounting groove 32. The present invention uses different mounting groove depths to make the compensating device further away from the magnetic field to be measured than the measuring device, thereby reducing the sensitivity of the compensating device to the magnetic field to be measured.

[0038] 2. The present invention also provides a magnetic shielding layer at the bottom of the compensation device installation slot, further reducing the sensitivity of the compensation device to the magnetic field to be measured.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A magneto-electric composite magnetic sensitive device with a differential structure, characterized in that: include: Measuring device (1), compensation device (2), device support (3) and magnetic shielding layer (4); The measuring device (1), the compensating device (2), and the magnetic shielding layer (4) are installed in the device bracket (3); The measuring device (1) is located above the magnet to be measured, and the length direction of the measuring device (1) is parallel to the magnetic field direction of the magnet to be measured, and is used to measure the magnitude of the magnetic field of the magnet to be measured; The compensation device (2) is placed orthogonally to the measuring device (1), and the magnetic shielding layer (4) is provided at the bottom of the measuring device (1) for shielding the magnetic field of the magnet to be measured parallel to the length direction of the compensation device (2), so as to collect the size of the spatial background magnetic field; The final magnetic field magnitude of the magnet to be measured is obtained by subtracting the acquired spatial background magnetic field magnitude from the measured magnetic field magnitude of the magnet to be measured; The measuring device (1) comprises: a measuring piezoelectric body (11), a measuring electrode (12) and a measuring magnetostrictive film (13), wherein the measuring electrodes (12) and the measuring magnetostrictive film (13) are sequentially provided outwardly on both sides of the measuring piezoelectric body (11); The measuring electrode (12) is mechanically connected to the measuring piezoelectric body (11), and the measuring magnetostrictive film (13) is mechanically connected to the measuring electrode (12). The compensation device (2) comprises: a compensation piezoelectric body (21), a compensation electrode (22) and a compensation magnetostrictive film (23), wherein the compensation electrode (22) and the compensation magnetostrictive film (23) are sequentially provided outwardly on both sides of the compensation piezoelectric body (21).

2. The magneto-electric composite magnetic sensitive device with a differential structure according to claim 1, characterized in that: The compensation electrode (22) and the compensation piezoelectric body (21), and the compensation magnetostrictive film (23) and the compensation electrode (22) are respectively mechanically connected.

3. The magneto-electric composite magnetic sensitive device with a differential structure according to claim 1, characterized in that: The measuring piezoelectric body (11) and the compensating piezoelectric body (21) have the same geometric dimensions and materials, the measuring electrode (12) and the compensating electrode (22) have the same geometric dimensions and materials, and the measuring magnetostrictive film (13) and the compensating magnetostrictive film (23) have the same geometric dimensions and materials.

4. The magneto-electric composite magnetic sensitive device with a differential structure according to claim 1, characterized in that: The device bracket (3) comprises: a measuring device mounting groove (31) and a compensating device mounting groove (32), wherein the depth of the measuring device mounting groove (31) is deeper than the depth of the compensating device mounting groove (32).

5. The magneto-electric composite magnetic sensitive device with a differential structure according to claim 4, characterized in that: The magnetic shielding layer (4) is arranged at the bottom of the compensation device installation groove (32).

6. The magneto-electric composite magnetic sensitive device with a differential structure according to claim 1, characterized in that: The measuring device (1), the compensating device (2), and the magnetic shielding layer (4) are all mechanically connected to the device bracket (3).

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