Magnetoelectric sensor capable of adjusting resonant frequency

Abstract

The invention discloses a magneto-electric sensor capable of adjusting resonant frequency. The magneto-electric sensor comprises an internal magneto-electric sensitive structure, an external packaging box and a regulation and control coil, the internal magnetoelectric sensitive structure comprises a piezoelectric material layer, an interdigital electrode layer and a magnetostrictive material layer are sequentially arranged on the two sides of the piezoelectric material layer, and every two adjacent layer structures are connected and fixed through an elastic medium layer; the external packaging box comprises a hollow support and a drawable platform, the drawable platform is slidably connected to the inner side of the hollow support, and the internal magnetoelectric sensitive structure is fixedly arranged in the drawable platform; wire grooves are formed in the two ends of the outer portion of the hollow support and are of a cylindrical structure. Regulation and control coils are wound in the two wire slots and are used for providing a magnetic field, and the number of turns and the winding directions of the two regulation and control coils are the same. The resonant frequency of the magnetoelectric sensor can be controlled by controlling the magnitude of the impressed current, the design operation is simple, the regulation and control speed is high, the cost is low, and the practicability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetoelectric sensors, and in particular to a magnetoelectric sensor with adjustable resonant frequency. Background Art

[0002] Magnetoelectric sensors are sensors based on the magnetoelectric effect, capable of directly converting magnetic field changes into electrical signals or indirectly coupling magnetic and electrical signals through mechanical deformation. Their core advantages lie in high sensitivity, low power consumption, and wide frequency response, making them suitable for detecting a variety of magnetic field-related physical quantities.

[0003] The sensitive element of a magnetoelectric sensor is typically composed of a stack of magnetostrictive materials (such as Metglas, which is sensitive to magnetic fields and produces deformation) and piezoelectric materials (such as PZT, which converts deformation into electric charge). Magnetic field changes are converted into voltage signals using the direct magnetoelectric effect. At room temperature, they exhibit a high magnetoelectric coupling coefficient. The larger this coefficient, the stronger the magnetoelectric conversion capability. In particular, some magnetoelectric sensors exhibit significant signal gain when operating near the mechanical resonant frequency (suitable for alternating magnetic field detection). In the resonant state, the magnetoelectric coupling coefficient can reach hundreds or even thousands of times that of the non-resonant state.

[0004] Based on the performance of magnetoelectric sensors, they have been applied to multiple fields of magnetic field detection at different frequencies: geomagnetic detection (geological exploration, navigation), biomedical non-invasive diagnosis, non-contact current sensing, non-destructive testing, energy collection, positioning detection, etc.

[0005] Due to the excellent performance of these sensors in alternating magnetic fields, enabling them to operate at different frequencies in a controlled manner is a hot topic in applied research. Currently, there are two main methods for controlling their operating frequency: one is to manipulate the material, such as type, size, coupling method, and structure; the other is to pre-regulate the external force on the sensitive material to change the material's stress state.

[0006] The above two methods are complex to operate and have low applicability. In order to meet the detection requirements of AC magnetic fields of different frequencies, the resonant frequency of the magnetoelectric sensor is relatively fixed, which is not convenient for measuring signals of a specified frequency. Summary of the Invention

[0007] The purpose of the present invention is to provide a magnetoelectric sensor with adjustable resonant frequency to solve the problems existing in the above-mentioned prior art.

[0008] To achieve the above object, the present invention provides a magnetoelectric sensor with adjustable resonant frequency, comprising:

[0009] An internal magnetoelectric sensitive structure, comprising a piezoelectric material layer, with an interdigital electrode layer and a magnetostrictive material layer sequentially disposed on both sides of the piezoelectric material layer, and two adjacent layer structures being connected and fixed by an elastic medium layer;

[0010] An external packaging box, comprising a hollow bracket and a retractable platform, wherein the retractable platform is slidably connected to the inner side of the hollow bracket, and the internal magnetoelectric sensitive structure is fixedly arranged inside the retractable platform; both ends of the outer side of the hollow bracket are provided with wire grooves, and the wire grooves are cylindrical structures;

[0011] A control coil is wound in each of the two wire slots. The control coil is used to provide a magnetic field. The number of turns and winding direction of the two control coils are the same.

[0012] Preferably, the magnetostrictive material layer is made of six layers of stacked and bonded Metglas material.

[0013] Preferably, the size of the Metglas material is 10 mm*80 mm.

[0014] Preferably, the interdigitated electrode layer is made of Kapton electrode material.

[0015] Preferably, copper wires are provided on the surface of the interdigitated electrode layer.

[0016] Preferably, the piezoelectric material layer includes four pieces of PMN-PT single crystal materials, and the four pieces of PMN-PT single crystal materials are arranged in sequence along the long axis direction.

[0017] Preferably, the thickness of the PMN-PT single crystal material is 200 μm.

[0018] Preferably, the elastic medium layer is an epoxy resin layer.

[0019] Preferably, the control coil is wound with enameled copper wire with a wire diameter of 0.5 mm, and the number of turns of the control coil is 76 turns.

[0020] Preferably, square support portions are provided at both ends of the wire trough of the hollow bracket.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] The magnetoelectric sensor with adjustable resonant frequency, provided by this invention, utilizes a piezoelectric single crystal material with enhanced piezomagnetic effect. While maintaining the internal magnetoelectric sensing structure, the package is redesigned. By controlling the current in an external control coil, a corresponding DC bias magnetic field is generated around the internal magnetoelectric sensing structure, thereby varying the material's piezoelectric strain constant and adjusting the resonant frequency. This design offers simple operation, rapid control speed, low cost, and high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a schematic structural diagram of the internal magnetoelectric sensitive structure of the present invention;

[0025] Figure 2 Schematic diagram of the structure of the hollow bracket of the present invention;

[0026] Figure 3 This is a schematic structural diagram of the retractable platform of the present invention;

[0027] Figure 4 This is a physical diagram of the magnetoelectric sensor with adjustable resonant frequency according to the present invention;

[0028] Figure 5 This is a performance test result diagram of the magnetoelectric sensor with adjustable resonant frequency of the present invention;

[0029] In the figure: 1. Magnetostrictive material layer; 2. Interdigital electrode layer; 3. Piezoelectric material layer; 4. Hollow bracket; 5. Retractable platform; 6. Wire trough. DETAILED DESCRIPTION

[0030] It should be noted that, unless there is a conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other. The embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0031] like Figures 1 to 4 As shown, the present invention provides a magnetoelectric sensor with adjustable resonant frequency, comprising:

[0032] An internal magnetoelectric sensitive structure includes a piezoelectric material layer 3, with an interdigital electrode layer 2 and a magnetostrictive material layer 1 sequentially arranged on both sides of the piezoelectric material layer 3, and two adjacent layer structures are connected and fixed by an elastic medium layer;

[0033] The external packaging box includes a hollow bracket 4 and a retractable platform 5. The retractable platform 5 is slidably connected to the inner side of the hollow bracket 4, and the internal magnetoelectric sensitive structure is fixedly arranged inside the retractable platform 5. Both ends of the outer side of the hollow bracket 4 are provided with wire grooves 6, which are cylindrical structures.

[0034] Control coils: Control coils are wound in both wire slots 6. The control coils are used to provide a magnetic field. The number of turns and winding direction of the two control coils are the same.

[0035] When the present invention works in a magnetic field environment, the magnetostrictive material is deformed, and the strain causes the tightly adhered piezoelectric material layer 3 to be subjected to stress changes, thereby generating a corresponding electric polarization effect, causing the output voltage at both ends of the interdigital electrodes to change.

[0036] The structure and operation method of the present invention are relatively simple. Without changing the sensitive components, a magnetoelectric sensor with adjustable resonant frequency is obtained based on the external magnetic field regulation effect of material properties. It has the advantages of small size and high degree of integration. The resonant frequency of the magnetoelectric sensor can be controlled by controlling the size of the external current.

[0037] According to a further optimized solution, the magnetostrictive material layer 1 is made of six layers of stacked and bonded Metglas material.

[0038] After further optimization, the size of the Metglas material is 10mm*80mm.

[0039] In a further optimized solution, the interdigitated electrode layer 2 is made of Kapton electrode material.

[0040] In a further optimized solution, copper wires are provided on the surface of the interdigital electrode layer 2 .

[0041] According to a further optimized solution, the piezoelectric material layer 3 includes four pieces of PMN-PT single crystal materials, and the four pieces of PMN-PT single crystal materials are arranged in sequence along the long axis direction.

[0042] After further optimization, the thickness of the PMN-PT single crystal material is 200 μm.

[0043] According to a further optimized solution, the elastic medium layer is an epoxy resin layer.

[0044] To further optimize the solution, the control coil is wound with enameled copper wire with a wire diameter of 0.5 mm, and the number of turns of the control coil is 76.

[0045] As a further optimization solution, square support portions are provided at both ends of the wire trough 6 of the hollow bracket 4 .

[0046] The magnetoelectric sensor with adjustable resonant frequency provided by the present invention comprises four PMN-PT single crystals arranged horizontally along their long axes. Two interdigitated electrode layers 2 made of Kapton electrode material are adhered to the top and bottom surfaces of the PMN-PT single crystals using epoxy resin. Six layers of Metglas foil are overlapped and bonded together to form a magnetostrictive material layer 1. This magnetostrictive material layer 1 is adhered to the side of the interdigitated electrode layer 2 facing away from the piezoelectric material layer 3 using epoxy resin. During adhesion, the Metglas material within the magnetostrictive material layer 1 and the PMN-PT single crystal material within the piezoelectric material layer 3 are aligned vertically. The sensor is then pressurized and cured using a vacuum pump. This produces an internal magnetoelectric sensing structure. The internal magnetoelectric sensing structure is secured within a retractable platform 5, which is then positioned within a hollow support 4. Control coils are wound in wire slots 6 at each end of the hollow support 4, with the number of turns and direction of winding being consistent.

[0047] The output voltage of the present invention in an AC magnetic field environment is tested by changing the current of the control coil, and the AC magnetic sensitivity is measured using a detection circuit based on a phase-locked amplifier. The magnetoelectric sensor is placed in a group of Helmholtz coils, the control coil is used to provide a DC magnetic field, and the Helmholtz coil is used to provide an AC magnetic field. The phase-locked amplifier is used to control the input of AC magnetic fields of different frequencies, and a frequency sweep test is performed on the sensor. After changing the DC current of the control coil, the frequency sweep test is performed again, and the operation is repeated. Record the output voltage obtained when the control coil is set to different current sizes, and draw a relationship diagram between frequency and output voltage. Figure 5 As shown, the resonant frequency can be controlled by adjusting the current of the coil.

[0048] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A magnetoelectric sensor with adjustable resonant frequency, characterized in that: include: An internal magnetoelectric sensitive structure, comprising a piezoelectric material layer (3), with an interdigital electrode layer (2) and a magnetostrictive material layer (1) sequentially provided on both sides of the piezoelectric material layer (3), and two adjacent layer structures being connected and fixed via an elastic medium layer; An external packaging box, the external packaging box comprising a hollow bracket (4) and a drawable platform (5), the drawable platform (5) being slidably connected to the inner side of the hollow bracket (4), and the internal magnetoelectric sensitive structure being fixedly arranged inside the drawable platform (5); both ends of the outer side of the hollow bracket (4) are provided with wire grooves (6), and the wire grooves (6) are cylindrical structures; A control coil is wound in each of the two wire slots (6), and the control coil is used to provide a magnetic field. The number of turns and the winding direction of the two control coils are the same.

2. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: The magnetostrictive material layer (1) is made of six layers of stacked and bonded Metglas material.

3. The magnetoelectric sensor with adjustable resonant frequency according to claim 2, characterized in that: The size of the Metglas material is 10 mm*80 mm.

4. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: The interdigitated electrode layer (2) is made of Kapton electrode material.

5. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: Copper wires are provided on the surface of the interdigital electrode layer (2).

6. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: The piezoelectric material layer (3) comprises four pieces of PMN-PT single crystal materials, and the four pieces of PMN-PT single crystal materials are arranged in sequence along the long axis direction.

7. The magnetoelectric sensor with adjustable resonant frequency according to claim 6, characterized in that: The thickness of the PMN-PT single crystal material is 200 μm.

8. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: The elastic medium layer is an epoxy resin layer.

9. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: The control coil is wound with enameled copper wire with a wire diameter of 0.5 mm, and the number of turns of the control coil is 76.

10. The magnetoelectric sensor with adjustable resonant frequency according to claim 1, characterized in that: Square support portions are provided at both ends of the wire trough (6) of the hollow bracket (4).

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