Magnetic field measurement sensor, system and method

Abstract

The present application discloses a magnetic field measurement sensor, system and method. The magnetic field measurement sensor includes: an excitation coil and a magnetoelectric sensitive unit; wherein the magnetoelectric sensitive unit is arranged inside the excitation coil; the excitation coil is used to receive a step signal, generate a current under the drive of the step signal, and generate an excitation magnetic field with a step change; the magnetoelectric sensitive unit is used to generate mechanical oscillation at a natural frequency under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured, and generate a target output voltage. The magnetic field measurement sensor system includes: a signal generation module, a demodulation module, a host computer and the above-mentioned magnetic field measurement sensor.

Description

Technical Field

[0001] The present application belongs to the field of magnetic field measurement technology, and specifically relates to a magnetic field measurement sensor, system and method. Background Art

[0002] Magnetostrictive materials or piezoelectric composite materials are widely used in magnetic sensors, actuators, energy harvesters and other fields due to their giant magnetoelectric effect. Magnetic field measurement sensors based on linear magnetoelectric effect can detect magnetic fields as low as 10 -12 T's alternating magnetic field, but the need for coils or permanent magnets to provide a DC bias field will increase the size and weight of the sensor. Sensors based on the nonlinear magnetoelectric effect can modulate the DC or AC magnetic field to be measured to the vicinity of the excitation magnetic field without applying a bias magnetic field, and can achieve high-sensitivity and low-noise magnetic field measurement.

[0003] However, the nonlinear magnetoelectric effect devices in the related technologies all use a coil to generate a continuous AC magnetic field to excite the magnetic field. This continuous excitation method of an external AC signal source will introduce crosstalk noise into the device, thereby affecting the signal-to-noise ratio. Summary of the invention

[0004] The embodiments of the present application provide a magnetic field measurement sensor, system and method, which can solve the problem of device crosstalk noise affecting the signal-to-noise ratio by continuous excitation by an external AC signal source.

[0005] In a first aspect, an embodiment of the present application provides a magnetic field measurement sensor, which includes: an excitation coil and a magneto-electric sensitive unit; wherein the magneto-electric sensitive unit is arranged inside the excitation coil; the excitation coil is used to receive a step signal, generate a current under the drive of the step signal, and generate an excitation magnetic field with a step change; the magneto-electric sensitive unit is used to mechanically oscillate at a natural frequency under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured, and generate a target output voltage.

[0006] In a second aspect, an embodiment of the present application provides a magnetic field measurement sensor system, the system comprising: a signal generating module, a demodulation module, a host computer and the magnetic field measurement sensor as described in the first aspect; wherein the host computer is connected to the signal generating module; the signal generating module is connected to the excitation coil of the magnetic field measurement sensor; the magnetic field measurement sensor is connected to the demodulation module; the demodulation module is connected to the host computer; wherein the signal generating module is used to generate a step signal under the control of the host computer, and input the step signal to the magnetic field measurement sensor.

[0007] In a third aspect, an embodiment of the present application provides a magnetic field measurement method, which is applied to the magnetic field measurement sensor system as described in the second aspect, and the method includes:

[0008] Inputting a step signal into a magnetic field measurement sensor to generate a target output voltage;

[0009] Inputting the target output voltage into a demodulation module for demodulation to obtain a magnetic field signal to be measured;

[0010] The magnetic field signal to be measured is input into a host computer for signal processing to obtain the magnetic field information to be measured;

[0011] The target output voltage is generated by the magnetoelectric sensitive unit of the magnetic field measurement sensor under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured; and the magnetic field signal to be measured carries the magnetic field information to be measured.

[0012] In the embodiment of the present application, the excitation coil of the magnetic field measurement sensor generates a current by receiving a step signal and driven by the step signal, thereby generating an excitation magnetic field with a step change; then the magnetoelectric sensitive unit of the magnetic field measurement sensor mechanically oscillates at a natural frequency under the excitation of the generated excitation magnetic field and the magnetic field to be measured, and generates a target output voltage, which is used for subsequent demodulation to obtain the magnetic field signal to be measured, thereby obtaining the magnetic field information to be measured based on the magnetic field signal to be measured. Different from using an external AC signal source to continuously excite the magnetoelectric sensitive unit, it can reduce the device crosstalk noise introduced by the external AC signal source, thereby affecting the signal-to-noise ratio, and can significantly improve the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural schematic diagram of a magnetic field measurement sensor provided in an embodiment of the present application;

[0014] Figure 2 is a structural schematic diagram of another magnetic field measurement sensor provided in an embodiment of the present application;

[0015] Figure 3 is a schematic diagram of the principle of nonlinear magnetoelectric effect of the magnetoelectric sensitive unit in the embodiment of the present application;

[0016] Figure 4 is a structural schematic diagram of another magnetic field measurement sensor provided in an embodiment of the present application;

[0017] Figure 5 is a structural cross-sectional diagram of a magnetic field measurement sensor provided in an embodiment of the present application;

[0018] Figure 6 is a schematic diagram of a step signal in an embodiment of the present application;

[0019] Figure 7 It is a waveform diagram of different output voltages generated by different biased DC magnetic field excitations to be measured in the embodiment of the present application;

[0020] Figure 8 is a structural schematic diagram of a magnetic field measurement sensor system provided in an embodiment of the present application;

[0021] Fig. 9 It is a flow chart of a magnetic field measurement method provided in an embodiment of the present application;

[0022] Fig.10 is a structural schematic diagram of another magnetic field measurement sensor system provided in an embodiment of the present application;

[0023] Fig.11 is a flow chart of another magnetic field measurement method provided in an embodiment of the present application;

[0024] Fig.12 yes Figure 7 The spectrum diagram of the waveform after Fourier transformation;

[0025] Fig.13 is a waveform diagram of the output voltage when the magnetic field measurement sensor in the embodiment of the present application measures a 1kHz magnetic field to be measured;

[0026] Fig.14 It is a frequency response curve diagram of the magnetic field measuring sensor measuring 1-50 kHz magnetic field in the embodiment of the present application;

[0027] Fig.15 is a curve diagram showing the change of the amplitude at the resonant frequency with the DC magnetic field to be measured in the embodiment of the present application;

[0028] Fig.16 It is a schematic diagram of the magnetoelectric sensitive unit in the embodiment of the present application measuring the magnetic field under the excitation of a step signal. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0031] The magnetic field measurement sensor, system and method provided in the embodiments of the present application are described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0032] Figure 1 FIG. 1 is a schematic diagram showing the structure of a magnetic field measurement sensor provided in an embodiment of the present application; Figure 1 As shown, the magnetic field measurement sensor 100 may include: an excitation coil 11 and a magneto-electric sensitive unit 12;

[0033] Wherein, the magnetoelectric sensitive unit 12 is arranged inside the excitation coil 11;

[0034] The excitation coil 11 is used to receive a step signal, generate a current under the drive of the step signal, and generate an excitation magnetic field with a step change;

[0035] The magneto-electric sensing unit 12 is used to generate a target output voltage by mechanically oscillating at a natural frequency under the excitation of a step-changing excitation magnetic field and a magnetic field to be measured.

[0036] In the embodiment of the present application, the excitation coil 11 of the magnetic field measurement sensor 100 generates an excitation magnetic field with a step change by receiving a step signal and generating a current under the drive of the step signal; Fig.16 The schematic diagram of the magnetic field measurement by the magnetoelectric sensitive unit in the embodiment of the present application under the excitation of the step signal is shown. After the magnetic field to be measured is introduced, the magnetoelectric sensitive unit 12 of the magnetic field measurement sensor 100 is mechanically oscillated at a natural frequency under the joint excitation of the generated excitation magnetic field and the introduced magnetic field to be measured. At this time, the oscillation frequency of the magnetoelectric sensitive unit 12 is not affected by the frequency of the step signal, and a target output voltage is generated. The target output voltage is used for subsequent demodulation to obtain the magnetic field signal to be measured, so as to obtain the magnetic field information to be measured according to the magnetic field signal to be measured. The device crosstalk noise introduced when using an external AC signal source to affect the signal-to-noise ratio is reduced, and the signal-to-noise ratio is further improved.

[0037] Figure 2FIG. 1 is a schematic diagram showing a structure of another magnetic field measurement sensor provided in an embodiment of the present application in one implementation manner; Figure 2 As shown, the magnetic field measurement sensor 200 includes: an excitation coil 21 and a magnetoelectric sensitive unit 22 , wherein the magnetoelectric sensitive unit 22 is obtained by combining a magnetostrictive material 221 and a piezoelectric material 222 .

[0038] Optionally, the magnetoelectric sensitive unit 22 may be formed by combining a magnetostrictive material 221 and a piezoelectric material 222 in different ways.

[0039] As a preferred manner, the magnetoelectric sensitive unit 22 can be obtained by compounding a magnetostrictive material 221 and a piezoelectric material 222 in a sheet-like stacking manner.

[0040] As a preferred method, the magnetostrictive material 221 can be made of iron-based amorphous alloy or cobalt-based amorphous alloy with high magnetic permeability and high-pressure magnetic coefficient. The piezoelectric material 222 can be made of perovskite type lead zirconate titanate (PZT) piezoelectric ceramics PZT or aluminum nitride (AlN).

[0041] Among them, under the action of a high-amplitude magnetic field, the magnetostrictive material 221 generates nonlinear magnetostrictive stress / strain, which is transmitted to the piezoelectric material 222. Due to the piezoelectric effect, a potential difference can be generated on the polarized surfaces of the piezoelectric material 222. Therefore, the magnetoelectric sensitive unit 22 composed of the magnetostrictive material 221 and the piezoelectric material 222 has a magneto-mechanical-electric coupling characteristic and a magnetoelectric effect, so that the magnetoelectric sensitive unit 22 can generate a voltage under the action of the magnetoelectric effect.

[0042] When magnetostrictive materials are subjected to magnetic fields, the fitting function of the magnetostrictive coefficient changing with the magnetic field can be expressed as:

[0043] λ(H)=λ s [1-exp(-αH 2 )] (1)

[0044] Where λ s is the saturation magnetostrictive strain. α is in Oe -2 The constant coefficient of . Figure 3 A schematic diagram showing the principle of the nonlinear magnetoelectric effect of the magnetoelectric sensitive unit in the embodiment of the present application is shown. Figure 3 It can be seen that the change of magnetostriction coefficient is an even function of magnetic field, that is, λ(-H) = λ(H). When the function of applying magnetic field to the magnetoelectric sensitive unit is:

[0045]

[0046] Where h 0 is the magnetic field to be measured, h 1 is the amplitude of the excitation magnetic field, f 0 and are the frequency and phase of the exciting magnetic field respectively. At this time, the output voltage of the magnetoelectric sensitive unit is:

[0047] U(t)=U[H(t)]=Adλ[H(t)] (3)

[0048] Where A is a constant related to the material geometry, performance parameters and composite mode, and d is the piezoelectric coefficient. Since the magnetostrictive coefficient varies nonlinearly with the magnetic field, the generated output voltage also varies nonlinearly with the magnetic field to be measured. At the same time, the magnetostrictive coefficient has even symmetry, which makes the output voltage U(t) also produce a frequency doubling effect. When the magnetic field to be measured is superimposed, the frequency doubling characteristics are destroyed, and the signal U(t) is accompanied by f 0 is the fundamental frequency, and the frequency 2f 0 、3f 0 、4f 0 Equal higher harmonic components.

[0049] The differential equation of the longitudinal free vibration of the magnetoelectric sensitive unit under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured can be expressed as:

[0050]

[0051] Where u is a function of time t and spatial longitudinal coordinate z; A and l are the cross-sectional area and length of the magnetoelectric sensitive unit, respectively; ρ and c are the average density and damping coefficient of the magnetoelectric sensitive unit, respectively; and K is the stiffness factor.

[0052] By substituting the boundary conditions and initial conditions into the differential equation and solving it, the longitudinal free oscillation equation of the magneto-electric sensitive unit under the excitation magnetic field and the magnetic field to be measured can be obtained as follows:

[0053]

[0054] Where H 0 and H 1 are the magnitudes of the magnetic field before and after the step change of the excitation magnetic field; ω is the natural frequency of the longitudinal vibration of the magnetoelectric sensitive unit; n 1 and n 2 are the volume proportions of magnetostrictive materials and piezoelectric materials, respectively; is the compliance coefficient of the magnetostrictive material; is the compliance coefficient of the piezoelectric material; α m and α p is the coefficient of thermal expansion.

[0055] According to the constitutive equation of piezoelectric materials, the potential difference V generated by the two polarized surfaces is related to the strain The relationship can be expressed as:

[0056]

[0057] Where D 3 is the electric displacement of the piezoelectric layer; is the dielectric constant under constant stress; d 31p is the piezoelectric constant; t p is the thickness of the piezoelectric layer. Substituting equation (5) into equation (6), we can obtain the relationship between the output voltage of the magnetoelectric sensitive unit after the excitation of the step-changing excitation magnetic field and the magnetic field to be measured:

[0058]

[0059] From equation (7), we can see that the output voltage of the magnetoelectric sensitive unit changes exponentially with time: Attenuation lasts for several milliseconds, and there is a bias related to the intensity before and after the step change of the magnetic field. Since the magnetostriction coefficient changes nonlinearly with the magnetic field, the output voltage of the magnetoelectric sensitive unit also changes nonlinearly with the change of the magnetic field. Due to the nonlinear magnetoelectric effect, the induced voltage of the magnetoelectric sensitive unit at resonance is modulated by the magnetic field to be measured. After determining the low and high levels of the excitation signal, the static and dynamic magnetic fields can be measured by demodulating the magnetic field signal to be measured in the output voltage signal.

[0060] Figure 4 FIG. 1 is a schematic diagram showing a structure of another magnetic field measurement sensor provided in an embodiment of the present application in one implementation manner; Figure 4 As shown, the magnetic field measurement sensor 400 includes: an excitation coil 41 and a magneto-electric sensitive unit 42 , and also includes a packaging shell 43 ; wherein the magneto-electric sensitive unit 42 is arranged inside the packaging shell 43 ; and the excitation coil 41 is wound around the outer surface of the packaging shell 43 .

[0061] Optionally, the excitation coil 41 may be wound in a manner of one layer with multiple turns or multiple layers with multiple turns.

[0062] Figure 5 FIG. 1 shows a cross-sectional view of a magnetic field measurement sensor provided by an embodiment of the present application in one implementation manner; Figure 5As shown, the excitation coil 51 is wound around the outer surface of the package shell 53, and the magnetoelectric sensitive unit 52 is fixed at the center of the package shell 53. The magnetoelectric sensitive unit 52 is composed of a magnetostrictive material 54 and a piezoelectric material 55; and electrode leads 56 are connected to the two surface electrodes of the piezoelectric material 55, and the electrode leads 56 can pass through the reserved small holes of the package shell 53 to be used for external connection with other devices, such as a signal amplifier.

[0063] As a preferred method, continue to refer to Figure 5 The center of the magneto-electric sensing unit 52 is clamped and fixed by the packaging shell 53, and the two ends are free. However, it is not limited to this, and other methods such as clamping at one end and free at the other end can also be used for fixing.

[0064] Figure 6 A schematic diagram of a step signal in an embodiment of the present application is shown; Figure 7 The waveform diagrams of different output voltages generated by different biased DC magnetic field excitations in the embodiment of the present application are shown. It can be seen that under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured, the magneto-electric sensitive unit undergoes mechanical oscillation. When the DC magnetic field to be measured is different, the waveform and amplitude of the output voltage are also different, so the magnetic field information to be measured can be obtained by demodulating the output voltage signal.

[0065] Figure 8 FIG. 1 is a schematic diagram showing a structure of a magnetic field measurement sensor system provided in an embodiment of the present application; Figure 8 As shown, the magnetic field measurement sensor system 800 may include: a signal generation module 81, a demodulation module 83, a host computer 84, and a magnetic field measurement sensor 82 as described in any of the above embodiments;

[0066] Wherein, the host computer 84 is connected to the signal generating module 81;

[0067] The signal generating module 81 is connected to the excitation coil of the magnetic field measuring sensor 82;

[0068] The magnetic field measurement sensor 82 is connected to the demodulation module 83;

[0069] The demodulation module 83 is connected to the host computer 84;

[0070] The signal generating module 81 is used to generate a step signal under the control of the host computer 84 , and input the step signal to the magnetic field measuring sensor 82 .

[0071] Fig. 9 A schematic diagram showing a flow chart of a magnetic field measurement method provided in an embodiment of the present application is shown; see Fig. 9 The method 900 is applied to Figure 8The magnetic field measurement sensor system 800 shown, the method 900 may include the following steps:

[0072] Step 910, inputting the step signal into the magnetic field measurement sensor 82 to generate a target output voltage;

[0073] Step 920, inputting the target output voltage into the demodulation module 83 for demodulation to obtain a magnetic field signal to be measured;

[0074] Step 930, inputting the magnetic field signal to be measured into the host computer 84 for signal processing to obtain the magnetic field information to be measured;

[0075] The target output voltage is generated by the magnetoelectric sensitive unit of the magnetic field measurement sensor 82 under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured; and the magnetic field signal to be measured carries the magnetic field information to be measured.

[0076] In the embodiment of the present application, the excitation coil of the magnetic field measurement sensor 82 receives a step signal and generates a current driven by the step signal, thereby generating an excitation magnetic field with a step change; then the magneto-electric sensitive unit of the magnetic field measurement sensor 82 oscillates mechanically at a natural frequency under the excitation of the generated excitation magnetic field and the magnetic field to be measured, and generates a target output voltage; then the magnetic field measurement sensor 82 inputs the target output voltage into the demodulation module 83 for demodulation to obtain a magnetic field signal to be measured that carries the magnetic field information to be measured; thereafter, the magnetic field signal to be measured is input into the host computer 84 for signal processing to obtain the magnetic field information to be measured, thereby realizing the measurement of the magnetic field to be measured.

[0077] Optionally, the host computer 84 is installed with specific software, which can perform autocorrelation analysis on the detected magnetic field signal to be measured and calculate the information of the magnetic field to be measured according to the autocorrelation function.

[0078] In one implementation, the following steps may be included before the above step 910:

[0079] Step 902, the host computer 84 sends a signal generation instruction to the signal generation module 81;

[0080] Step 904, the signal generating module 81 generates a step signal according to the received signal generating instruction;

[0081] The signal generation instruction is used to control the signal generation module 81 to generate an excitation signal, and the excitation signal includes a step signal.

[0082] In this embodiment, the step signal generation process includes the host computer 84 sending a signal generation instruction to the signal generation module 81, and the signal generation module 81 generates the step signal according to the instruction.

[0083] Fig.10 FIG. 1 shows a schematic diagram of the structure of another magnetic field measurement sensor system provided by an embodiment of the present application in one implementation manner; Fig.10 As shown, the magnetic field measurement sensor system 100 may include: a signal generation module 101, a demodulation module 103, a host computer 104 and a magnetic field measurement sensor 102 as described in any of the above embodiments; and may also include: a signal amplifier 105 and an analog-to-digital converter 106.

[0084] Among them, the host computer 104 is connected to the signal generating module 101; the signal generating module 101 is connected to the excitation coil of the magnetic field measuring sensor 102; the magnetic field measuring sensor 102 is connected to the signal amplifier 105; the signal amplifier 105 is connected to the demodulation module 103; the demodulation module 103 is connected to the analog-to-digital converter 106; and the analog-to-digital converter 106 is connected to the host computer 104.

[0085] Fig.11 FIG. 1 is a flow chart of another magnetic field measurement method provided by an embodiment of the present application in an implementation manner; Fig.11 As shown, the method 1100 is applied to Fig.10 The magnetic field measurement sensor system 100, the method 1100 may include:

[0086] Step 111, the host computer 104 sends a signal generation instruction to the signal generation module 101;

[0087] Step 112, the signal generating module 101 generates a step signal according to the received signal generating instruction;

[0088] Step 113, inputting the step signal into the magnetic field measurement sensor 102 to generate a target output voltage;

[0089] Step 114, inputting the target output voltage into the signal amplifier 105 for signal amplification processing;

[0090] Step 115, inputting the target output voltage after the signal amplification processing into the demodulation module 103 for demodulation to obtain a magnetic field signal to be measured;

[0091] Step 116, inputting the magnetic field signal to be measured into the analog-to-digital converter 106 for signal conversion processing;

[0092] Step 117, input the magnetic field signal to be measured after the signal conversion processing into the host computer 104 for signal processing to obtain the magnetic field information to be measured.

[0093] In the embodiment of the present application, first, the host computer 104 sends a signal generation instruction to the signal generating module 101, which is used to control the signal generating module 101 to generate an excitation signal, wherein the excitation signal includes a step signal; after the signal generating module 101 generates the step signal, the step signal is input into the magnetic field measuring sensor 102, and the magnetic field measuring sensor 102 generates a current under the drive of the step signal, thereby generating an excitation magnetic field with a step change; then, the magnetoelectric sensitive unit of the magnetic field measuring sensor 102 is excited by the generated excitation magnetic field and the magnetic field to be measured, A mechanical oscillation occurs at a certain frequency, and a magnetic-mechanical-electrical physical field conversion occurs to generate a target output voltage. After that, the target output voltage is first amplified by a signal amplifier 105, and then transmitted to a demodulation module 103. The demodulation module 103 demodulates the target output voltage after the signal amplification processing to obtain a magnetic field signal to be measured that carries the magnetic field information to be measured. The magnetic field signal to be measured is then converted by an analog-to-digital converter 106 and converted into a digital signal, which is then transmitted to a host computer 104 for signal processing, thereby obtaining the magnetic field information to be measured and realizing the measurement of the magnetic field to be measured.

[0094] In the process of implementing the magnetic field measurement method, on the one hand, using a step-changing magnetic field for excitation can reduce the power consumption of the magnetic field measurement sensor and reduce the cost; on the other hand, the magnetoelectric sensitive unit of the magnetic field measurement sensor oscillates at a natural frequency, which can significantly enhance the magnetoelectric effect, thereby improving the sensitivity of measuring the magnetic field, reducing the crosstalk noise introduced by the external AC signal source, and improving the signal-to-noise ratio.

[0095] also, Fig.12 Show Figure 7 From the spectrum diagram of the waveform after Fourier transformation, it can be seen that the amplitude at the resonant frequency changes with the DC magnetic field to be measured. This characteristic can be used to measure the DC magnetic field.

[0096] Fig.13 The waveform of the output voltage of the magnetic field measurement sensor in the embodiment of the present application when measuring the magnetic field to be measured at 1kHz is shown. It can be seen that the waveform changes periodically with the frequency of 1kHz, that is, the "mixing" phenomenon. The purpose of transferring the frequency of the magnetic field to be measured to near the resonant frequency is achieved, and the signal-to-noise ratio of the signal is improved. This characteristic can be used to measure the AC magnetic field.

[0097] Fig.14 FIG. 2 shows a frequency response curve of a magnetic field measuring sensor measuring a 1-50 kHz magnetic field in an embodiment of the present application. Fig.14As shown in the figure, the response value of the odd-order multiple frequency points with 2kHz as the fundamental frequency is significantly greater than the response value of other frequency points. The reason is that the odd harmonics with the excitation magnetic field frequency as the fundamental frequency will also mix with the resonant frequency. Since the amplitude of the excitation magnetic field is high, it drowns out the information of the AC magnetic field to be measured. Therefore, when designing magnetic field measurement sensor devices, frequency points with integer multiples of the excitation magnetic field frequency should be avoided. In the area with flat bandwidth response, the magnetoelectric sensitive unit has a higher sensitivity in measuring AC magnetic fields.

[0098] Fig.15 A curve diagram showing the change of the amplitude at the resonant frequency with the DC magnetic field to be measured in the embodiment of the present application is shown as follows: Fig.15 As shown, the magnetic field measurement sensor has good linearity and high sensitivity in the magnetic field range of -3 to 3Oe.

[0099] Therefore, the magnetic field measurement sensor, system and method provided in the embodiments of the present application can be used for high-precision measurement of weak magnetic fields such as the Earth's magnetic field.

[0100] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0101] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0102] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A magnetic field measurement sensor, characterized in that: include: Excitation coil and magnetoelectric sensitive unit; wherein, The magnetoelectric sensitive unit is arranged inside the excitation coil; The excitation coil is used to receive the step signal, generate a current under the drive of the step signal, and generate an excitation magnetic field with step changes; The magnetoelectric sensitive unit is used to generate mechanical oscillation at a natural frequency under the excitation of a step-changing excitation magnetic field and a magnetic field to be measured, generate a target output voltage, and output the target output voltage to a demodulation module so that the demodulation module demodulates the target output voltage to obtain a magnetic field signal to be measured that carries information about the magnetic field to be measured.

2. The magnetic field measuring sensor according to claim 1, characterized in that: The magnetoelectric sensitive unit is obtained by compounding a magnetostrictive material and a piezoelectric material.

3. The magnetic field measuring sensor according to claim 2, characterized in that: The magnetostrictive material and the piezoelectric material are compounded in a sheet-like stacking manner.

4. The magnetic field measuring sensor according to claim 1, characterized in that: The magnetic field measurement sensor also includes a packaging shell; wherein, The magnetoelectric sensitive unit is arranged inside the packaging shell; The excitation coil is wound around the outer surface of the packaging shell.

5. A magnetic field measurement sensor system, characterized in that: include: A signal generating module, a demodulating module, a host computer and a magnetic field measuring sensor as claimed in any one of claims 1 to 4; wherein, The host computer is connected to the signal generating module; The signal generating module is connected to the excitation coil of the magnetic field measuring sensor; The magnetic field measurement sensor is connected to the demodulation module; The demodulation module is connected to the host computer; The signal generating module is used to generate a step signal under the control of the host computer, and input the step signal into the magnetic field measuring sensor.

6. The system according to claim 5, characterized in that The system further comprises: a signal amplifier and an analog-to-digital converter; wherein, The signal amplifier is connected to the magnetic field measurement sensor and the demodulation module; The analog-to-digital converter is connected to the demodulation module and the host computer.

7. A magnetic field measurement method, applied to the magnetic field measurement sensor system according to any one of claims 5 to 6, characterized in that: include: Inputting a step signal into a magnetic field measurement sensor to generate a target output voltage; Inputting the target output voltage into a demodulation module for demodulation to obtain a magnetic field signal to be measured; The magnetic field signal to be measured is input into a host computer for signal processing to obtain the magnetic field information to be measured; The target output voltage is generated by the magnetoelectric sensitive unit of the magnetic field measurement sensor under the excitation of the step-changing excitation magnetic field and the magnetic field to be measured; and the magnetic field signal to be measured carries the magnetic field information to be measured.

8. The method according to claim 7, characterized in that Before the step signal is input into the magnetic field measurement sensor to generate the target output voltage, it also includes: The host computer sends a signal generation instruction to the signal generation module; The signal generating module generates a step signal according to the received signal generating instruction; The signal generation instruction is used to control the signal generation module to generate an excitation signal, and the excitation signal includes a step signal.

9. The method according to claim 7, characterized in that: Before inputting the target output voltage into a demodulation module for demodulation to obtain a magnetic field signal to be measured, the method further includes: The target output voltage is input into a signal amplifier for signal amplification processing.

10. The method according to claim 7, characterized in that Before the magnetic field signal to be measured is input into the host computer for signal processing to obtain the magnetic field information to be measured, the method further includes: The magnetic field signal to be measured is input into an analog-to-digital converter for signal conversion processing.

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