A fluxgate sensor and working method thereof

Abstract

The present disclosure provides a fluxgate sensor, including: a probe, an excitation module and a detection module; the probe includes three fluxgate groups, each fluxgate group includes two mutually parallel fluxgates; the fluxgate includes an excitation coil and an induction coil; the excitation coil is connected to the excitation module, the induction coil is connected to the detection module, and the excitation module is connected to the detection module; the three fluxgate groups are orthogonally installed, and a fluxgate group is arranged between the two fluxgates included in each fluxgate group. The method for setting the fluxgate of the fluxgate sensor provided by the present disclosure can reduce the volume of the probe, so that the fluxgate sensor is suitable for more measurement scenarios. The present disclosure also provides a working method of the fluxgate sensor.

Description

Technical Field

[0001] The present disclosure relates to the field of sensor technology, and in particular to a fluxgate sensor and a working method thereof. Background Art

[0002] The magnetic component of the electromagnetic field generated by the electrical activity of the heart during the cardiac cycle, which is recorded and analyzed by non-invasive means, is called magnetocardiography (MCG). However, compared with the magnetic field strength of the earth (10-4T), the measured value of the heart is extremely weak, so the commonly used magnetic field sensors are only superconducting quantum interference device (SQUID) and optical pump magnetic field sensor (OPM). SQUID sensor has extremely low equivalent input magnetic field noise (3-100fT / √Hz) and is one of the most sensitive magnetic field sensors at present. However, SQUID sensor is not only huge in size but also needs to work in a low-temperature environment cooled by liquid nitrogen or liquid helium, which is demanding. In addition, since MCG requires three-dimensional vector measurement, in order to reduce the size of SQUID sensor, BX and BY components are determined by indirect method of BZ gradient along X and Y directions, which brings inconvenience to actual measurement. OPM sensor can work at room temperature with a maximum sensitivity of 50-100fT / √Hz. However, it is not widely used in MCG measurement because of its disadvantages such as being time-consuming and expensive to measure, only measuring the total field, not providing information on the direction of the magnetic field, and having blank areas in certain magnetic field directions. Existing fluxgate sensors are mostly annular magnetic or discrete parallel dual cores, which are relatively large in size and have high noise, and are not suitable for MCG measurement. Summary of the invention

[0003] In view of the above problems, the present disclosure provides a fluxgate sensor and a working method thereof.

[0004] According to a first aspect of the present disclosure, there is provided a fluxgate sensor, comprising: a probe, an excitation module and a detection module;

[0005] The probe includes three fluxgate groups, each of which includes two fluxgates parallel to each other;

[0006] The fluxgate includes an excitation coil and an induction coil;

[0007] The excitation coil is connected to the excitation module, the induction coil is connected to the detection module, and the excitation module is connected to the detection module;

[0008] The three fluxgate groups are installed orthogonally, and one fluxgate group is arranged between two fluxgates included in each fluxgate group.

[0009] Optionally, the fluxgate further comprises: a magnetic core and a magnetic core skeleton;

[0010] An excitation coil is wound on the magnetic core;

[0011] The induction coil is wound on the magnetic core frame;

[0012] The magnetic core frame is a hollow structure, the magnetic core wound with the excitation coil is arranged in the hollow structure of the magnetic core frame, and the magnetic core wound with the excitation coil is parallel to the axis of the magnetic core frame;

[0013] The excitation coils of the two fluxgates in each fluxgate group are connected in series in opposite directions, and the induction coils of the two fluxgates in each fluxgate group are connected in series in the same direction;

[0014] The input end of the excitation coil is connected to the excitation module, and the output end of the excitation coil is grounded.

[0015] Optionally, the excitation module includes: a waveform generator, a frequency divider, a power amplifier and a matching network;

[0016] The waveform generator is used to generate a square wave signal;

[0017] The input end of the frequency divider is connected to the output end of the waveform generator, and the frequency divider is used to perform frequency division processing on the square wave signal to obtain a frequency division signal;

[0018] The input end of the power amplifier is connected to the first output end of the frequency divider, and the power amplifier is used to perform frequency selection and amplification processing on the frequency-divided signal to obtain an excitation signal;

[0019] The input end of the matching network is connected to the output end of the power amplifier, the output end of the matching network is connected to the input end of the excitation coil, and the matching network is used to adjust the amplitude and phase of the excitation signal.

[0020] Optionally, the excitation module includes a frequency divider for generating a frequency-divided signal, and the detection module includes: a demodulator, a filter, and a feedback network;

[0021] The first input end of the demodulator is connected to the second output end of the frequency divider, the second input end of the demodulator is connected to the output end of the induction coil, and the demodulator is used to adjust the frequency of the induction signal generated by the induction coil;

[0022] The input end of the filter is connected to the output end of the demodulator, and the filter is used to filter the frequency-adjusted induction signal to obtain a measurement value;

[0023] The input end of the feedback network is connected to the first output end of the filter, and the output end of the feedback network is connected to the input end of the induction coil. The feedback network is used to input the measured value into the induction coil so that the induction coil generates a feedback magnetic field. The magnetic field strength of the feedback magnetic field is the same as that of the measured magnetic field, and the magnetic field direction of the feedback magnetic field is opposite to that of the measured magnetic field.

[0024] Optionally, the two fluxgates included in each fluxgate group are spaced apart by the same preset distance.

[0025] Optionally, two ends of the two fluxgates included in each fluxgate group are aligned.

[0026] Optionally, the wire diameter of the excitation coil is 0.035 mm to 0.1 mm, and the number of turns of the excitation coil is 200 to 2000 turns;

[0027] The wire diameter of the induction coil is 0.05 mm to 0.2 mm, and the number of turns of the induction coil is 800 to 3000 turns.

[0028] Optionally, the diameter of the magnetic core is 50-300 mm and the length is 10-30 mm.

[0029] Optionally, it also includes: a power module, the power module is connected to the excitation module and the detection module, and the power module is used to supply power to the excitation module and the detection module.

[0030] According to a second aspect of the present disclosure, there is provided a working method of the fluxgate sensor as described above, comprising:

[0031] Using the excitation module to generate an excitation signal and a frequency division signal;

[0032] All the excitation coils in the probe are driven by the excitation signal so that the magnetic cores wound with the excitation coils are all in an excitation saturation state;

[0033] All the magnetic cores in the excitation saturation state are used to make all the induction coils in the probe generate induction signals;

[0034] Using the detection module to obtain the measurement value according to the frequency division signal and the induction signal;

[0035] The detection module is used to input the measured value into all the induction coils in the probe, so that all the induction coils generate a feedback magnetic field with the same magnetic field strength and opposite direction to the measured magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 The schematic diagram of the structure of a fluxgate sensor provided by an embodiment of the present disclosure is shown;

[0038] Figure 2 The structure diagram of a fluxgate of a fluxgate sensor provided by an embodiment of the present disclosure is schematically shown;

[0039] Figure 3 A schematic diagram of the three-dimensional structure of a fluxgate sensor provided by an embodiment of the present disclosure is shown; and

[0040] Figure 4 A flow chart of a fluxgate sensor working method provided by an embodiment of the present disclosure is schematically shown.

[0041] Description of reference numerals:

[0042] 10 probe; 11 flux gate; 12 excitation coil; 13 induction coil; 14 magnetic core; 15 magnetic core skeleton; 20 excitation module; 21 waveform generator; 22 divider; 23 power amplifier; 24 matching network; 30 detection module; 31 demodulator; 32 filter; 33 feedback network; 40 power supply module. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0044] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0045] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0046] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). Those skilled in the art should also understand that any transitional conjunctions and / or phrases that substantially indicate two or more optional items, whether in the specification, claims, or drawings, should be understood to give the possibility of including one of these items, either of these items, or both of these items. For example, the phrase "A or B" should be understood to include the possibilities of "A" or "B", or "A and B".

[0047] The present disclosure provides a fluxgate sensor, comprising: a probe, an excitation module and a detection module; the probe comprises three fluxgate groups, each fluxgate group comprises two mutually parallel fluxgates; the fluxgate comprises an excitation coil and an induction coil; the excitation coil is connected to the excitation module, the induction coil is connected to the detection module, and the excitation module is connected to the detection module; the three fluxgate groups are orthogonally installed, and a fluxgate group is arranged between the two fluxgates included in each fluxgate group. The method for setting the fluxgate of the fluxgate sensor provided by the present disclosure can reduce the volume of the probe, so that the fluxgate sensor is suitable for more measurement scenarios.

[0048] The following will be passed Figure 1 to Figure 3 A fluxgate sensor of the disclosed embodiment is described in detail to help those skilled in the art to more clearly understand the technical solution of the present disclosure.

[0049] Figure 1 The schematic diagram shows the structure of a fluxgate sensor provided by an embodiment of the present disclosure. Figure 2 The schematic diagram shows the structure of a fluxgate of a fluxgate sensor provided by an embodiment of the present disclosure. Figure 3A schematic diagram of the three-dimensional structure of a fluxgate sensor provided by an embodiment of the present disclosure is schematically shown.

[0050] refer to Figures 1 to 3 In one embodiment of the present disclosure, the fluxgate sensor includes: a probe 10, an excitation module 20 and a detection module 30; the probe 10 includes three fluxgate groups, each fluxgate group includes two mutually parallel fluxgates 11; the fluxgate 11 includes an excitation coil 12 and an induction coil 13; the excitation coil 12 is connected to the excitation module 20, the induction coil 13 is connected to the detection module 30, and the excitation module 20 is connected to the detection module 30; the three fluxgate groups are orthogonally installed, and a fluxgate group is arranged between the two fluxgates included in each fluxgate group.

[0051] In this embodiment, the fluxgate sensor includes a probe 10, and the probe 10 is provided with three fluxgate groups in an orthogonal structure, each fluxgate group includes two fluxgates 11 parallel to each other, and the two fluxgates 11 included in each fluxgate group are spaced at the same preset distance, and the two ends of the two fluxgates 11 included in each fluxgate group are aligned. The specific spacing distance can be set according to actual needs, and the present disclosure does not limit this. A fluxgate group is also provided between the two fluxgates 11 included in each fluxgate group (refer to Figure 3 ), each fluxgate 11 includes an excitation coil 12 and an induction coil 13, the wire diameter of the excitation coil 12 can be 0.035mm~0.1mm, the number of turns of the excitation coil 12 can be 200~2000 turns, the wire diameter of the induction coil 13 can be 0.05mm~0.2mm, and the number of turns of the induction coil 13 can be 800~3000 turns. Among them, the excitation coil 12 is connected to the excitation module 20, and the induction coil 13 is connected to the detection module 30. The setting method of the fluxgate of the fluxgate sensor provided in the present disclosure can reduce the volume of the probe, so that the fluxgate sensor is suitable for more measurement scenarios.

[0052] refer to Figures 1 to 3 In one embodiment of the present disclosure, the fluxgate 11 further includes: a magnetic core 14 and a magnetic core skeleton 15; an excitation coil 12 is wound on the magnetic core 14; the induction coil 13 is wound on the magnetic core skeleton 15; the magnetic core skeleton 15 is a hollow structure, the magnetic core 14 with the excitation coil 12 wound on it is arranged in the hollow structure of the magnetic core skeleton 15, and the magnetic core 14 with the excitation coil 12 wound on it is parallel to the axis of the magnetic core skeleton 15; the excitation coils 12 of the two fluxgates 11 in each fluxgate group are connected in series in reverse direction, and the induction coils 13 of the two fluxgates 11 in each fluxgate group are connected in series in the same direction; the input end of the excitation coil 12 is connected to the excitation module 20, and the output end of the excitation coil 12 is grounded.

[0053] In this embodiment, the fluxgate 11 further includes a magnetic core 14 and a magnetic core skeleton 15, wherein the excitation coil 12 is wound on the magnetic core 14, and the induction coil 13 is wound on the magnetic core skeleton 15. The diameter of the magnetic core 14 can be 50 to 300 mm, and the length can be 10 to 30 mm. The magnetic core skeleton 15 in this embodiment is a hollow structure, and the magnetic core 14 with the excitation coil 12 wound is arranged in the hollow structure, and the magnetic core 14 is parallel to the axis of the magnetic core skeleton 15 (such as Figure 3 The excitation coils 12 in the two fluxgates 11 included in each fluxgate group are connected in series in opposite directions, and the induction coils 13 are connected in series in the same direction. The magnetic core in the fluxgate provided by the present disclosure is arranged in the hollow structure of the magnetic core skeleton, which reduces the volume of the fluxgate and further reduces the volume of the fluxgate sensor.

[0054] It should be understood that the examples of the sizes of the components in the fluxgate sensor in this embodiment are only exemplary to help those skilled in the art understand the technical solution of the present disclosure, and are not intended to limit the protection scope of the present disclosure.

[0055] refer to Figures 1 to 3 In one embodiment of the present disclosure, the excitation module 20 includes: a waveform generator 21, a frequency divider 22, a power amplifier 23 and a matching network 24; the waveform generator 21 is used to generate a square wave signal; the input end of the frequency divider 22 is connected to the output end of the waveform generator 21, and the frequency divider 22 is used to perform frequency division processing on the square wave signal to obtain a frequency division signal; the input end of the power amplifier 23 is connected to the first output end of the frequency divider 22, and the power amplifier 23 is used to perform frequency selection and amplification processing on the frequency division signal to obtain an excitation signal; the input end of the matching network 24 is connected to the output end of the power amplifier 23, and the output end of the matching network 24 is connected to the input end of the excitation coil 12, and the matching network 24 is used to adjust the amplitude and phase of the excitation signal.

[0056] In this embodiment, the excitation module 20 includes a waveform generator 21, a frequency divider 22, a power amplifier 23 and a matching network 24. When the fluxgate sensor provided by the present disclosure is used for measurement, the waveform generator 21 generates a periodic square wave signal, which is first divided by the frequency divider 22, then frequency selected and amplified by the power amplifier 23, and finally the amplitude and phase thereof are adjusted by the matching network 24. For example, a 32kHz oscillation waveform signal is generated by a crystal oscillator and an inverter, and the signal is passed through a 4-fold frequency divider to generate a double frequency signal with a frequency of 8kHz, which provides a reference signal for the detection module, and a baseband signal with a frequency of 4kHz is generated by an 8-fold frequency divider to provide an excitation signal for the excitation coil. The power amplifier further amplifies the power of the baseband signal for driving the excitation coil, and a large excitation magnetic field is achieved by generating a large current on the excitation coil. The matching network is matched through an impedance network to tune the frequency of the excitation coil and the excitation signal.

[0057] It should be understood that the examples of the waveform generator model and the frequency of the square wave signal in this embodiment are merely exemplary to help those skilled in the art understand the technical solution of the present disclosure, and are not intended to limit the protection scope of the present disclosure.

[0058] refer to Figures 1 to 3 In one embodiment of the present disclosure, the excitation module 20 includes a frequency divider 22 for generating a frequency division signal, and the detection module 30 includes: a demodulator 31, a filter 32 and a feedback network 33; the first input end of the demodulator 31 is connected to the second output end of the frequency divider 22, the second input end of the demodulator 31 is connected to the output end of the induction coil 13, and the demodulator 31 is used to adjust the frequency of the induction signal generated by the induction coil 13; the input end of the filter 32 is connected to the output end of the demodulator 31, and the filter 32 is used to filter the induction signal after the frequency adjustment to obtain a measurement value; the input end of the feedback network 33 is connected to the first output end of the filter 32, the output end of the feedback network 33 is connected to the input end of the induction coil 13, and the feedback network 33 is used to input the measurement value into the induction coil 13, so that the induction coil 13 generates a feedback magnetic field, the magnetic field strength of the feedback magnetic field is the same as the measured magnetic field, and the magnetic field direction of the feedback magnetic field is opposite to the measured magnetic field.

[0059] In this embodiment, the detection module 30 includes a demodulator 31, a filter 32 and a feedback network 33. After the excitation signal generated by the excitation module 20 is transmitted to the excitation coil 12, the magnetic core 14 wound with the excitation coil 12 is in an excitation saturation state, so that the induction coil 13 wound on the magnetic core skeleton 15 generates an induction signal, and the induction coil 13 is connected to the demodulator 31 in the detection module 30. The demodulator 31 receives the frequency division signal output by the frequency divider 22 in the excitation module 20, and adjusts the frequency of the induction signal accordingly. The filter 32 performs filtering processing on the induction signal after the frequency adjustment to obtain the final measurement value, and transmits the measurement value to the feedback network 33. The feedback network 33 is connected to the induction coil 13, and the feedback network 33 transmits the measurement value to the induction coil 13, so that the induction coil 13 generates a feedback magnetic field with a direction opposite to the measured magnetic field and the same magnetic field strength. The feedback magnetic field offsets the measured magnetic field, so that the magnetic core 14 is close to the zero magnetic space. The fluxgate sensor provided by the present disclosure adopts closed-loop feedback, which can effectively improve the stability of the system, expand the dynamic range, and reduce the nonlinearity of the system. For example, the most commonly used second harmonic detection method can be used. The induced signal and the doubled frequency signal (i.e., the divided frequency signal) are passed through an analog multiplier to realize signal demodulation. The demodulated signal passes through a low-pass filter circuit to separate the useful signal proportional to the magnetic field. The low-pass filter circuit realizes the two functions of amplification and filtering, and a low-power low-noise amplifier such as AD8607 (noise less than 10nV / √Hz, current less than 40uA) can be used.

[0060] In one embodiment of the present disclosure, the fluxgate sensor further includes a power module 40 , which is connected to the excitation module 20 and the detection module 30 , and is used to supply power to the excitation module 20 and the detection module 30 .

[0061] It should be understood that Figure 1 to Figure 3 The sizes, shapes, etc. of the components in the fluxgate sensor shown in the figure are only exemplary, so as to facilitate those skilled in the art to understand the solution of the present disclosure, and are not intended to limit the protection scope of the present disclosure. In some other embodiments, the sizes, shapes, etc. of the components in the above fluxgate sensor can be selected according to actual conditions and are not limited here.

[0062] Based on the above fluxgate sensor, the present disclosure also provides a working method of the fluxgate sensor. Figure 4 The working method of the above fluxgate sensor is described in detail.

[0063] Figure 4 A flow chart of a fluxgate sensor working method provided by an embodiment of the present disclosure is schematically shown.

[0064] like Figure 4 As shown, in one embodiment of the present disclosure, the working method includes operations S410 to S450.

[0065] In operation S410, an excitation signal and a frequency division signal are generated by using an excitation module.

[0066] In operation S420, all the excitation coils in the probe are driven by an excitation signal so that the magnetic cores wound with the excitation coils are in an excitation saturation state.

[0067] In operation S430, all the magnetic cores in the excitation saturation state are used to make all the induction coils in the probe generate induction signals.

[0068] In operation S440, a detection module is used to obtain a measurement value according to the frequency-divided signal and the sensing signal.

[0069] In operation S450, the detection module is used to input the measured values ​​into all the induction coils in the probe, so that all the induction coils generate a feedback magnetic field with a direction opposite to the measured magnetic field and a same magnetic field strength.

[0070] When the fluxgate sensor provided by the present disclosure is used for measurement, after the fluxgate sensor provided by the present disclosure is placed in the measured magnetic field, an excitation module is used to generate an excitation signal and a frequency division signal, wherein the excitation signal is transmitted to the excitation coil, so that the magnetic core wound with the excitation coil is in an excitation saturation state, and the magnetic core in the excitation saturation state is used to make the induction coil generate an induction signal, and the detection module is used to process the induction signal according to the frequency division signal to obtain a measured value, and the measured value is transmitted to the induction coil, so that the induction coil generates a feedback magnetic field in the opposite direction to the measured magnetic field. The feedback magnetic field is used to offset the measured magnetic field near the magnetic core, so that the magnetic core is close to the zero magnetic space, which can effectively improve the stability of the fluxgate sensor, expand the dynamic range, and reduce the nonlinearity of the fluxgate sensor.

[0071] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0072] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the present disclosure has been shown and described with reference to specific exemplary embodiments of the present disclosure, it should be understood by those skilled in the art that various changes in form and detail may be made to the present disclosure without departing from the spirit and scope of the present disclosure as defined by the attached claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-mentioned embodiments, but should be determined not only by the attached claims, but also by the equivalents of the attached claims.

Claims

1. A fluxgate sensor, characterized in that: include: A probe (10), an excitation module (20) and a detection module (30); The probe (10) comprises three fluxgate groups, each fluxgate group comprising two mutually parallel fluxgates (11); The fluxgate (11) comprises an excitation coil (12), an induction coil (13), a magnetic core (14) and a magnetic core skeleton (15); The excitation coil (12) is connected to the excitation module (20), the induction coil (13) is connected to the detection module (30), and the excitation module (20) and the detection module (30) are connected; the excitation coil (12) is wound on the magnetic core (14); the induction coil (13) is wound on the magnetic core skeleton (15); the magnetic core skeleton (15) is a hollow structure, and the magnetic core (14) on which the excitation coil (12) is wound is arranged on the magnetic core skeleton ( 15), and the magnetic core (14) wound with the excitation coil (12) is parallel to the axis of the magnetic core skeleton (15); the excitation coils (12) of the two fluxgates (11) in each fluxgate group are connected in series in reverse direction, and the induction coils (13) of the two fluxgates (11) in each fluxgate group are connected in series in the same direction; the input end of the excitation coil (12) is connected to the excitation module (20), and the output end of the excitation coil (12) is grounded; The three fluxgate groups are orthogonally installed, and one fluxgate group is arranged between two fluxgates (11) included in each fluxgate group; The excitation module (20) comprises: a waveform generator (21), a frequency divider (22), a power amplifier (23) and a matching network (24); The waveform generator (21) is used to generate a square wave signal; The input end of the frequency divider (22) is connected to the output end of the waveform generator (21), and the frequency divider (22) is used to perform frequency division processing on the square wave signal to obtain a frequency division signal; The input end of the power amplifier (23) is connected to the first output end of the frequency divider (22), and the power amplifier (23) is used to perform frequency selection and amplification processing on the frequency-divided signal to obtain an excitation signal; The input end of the matching network (24) is connected to the output end of the power amplifier (23), the output end of the matching network (24) is connected to the input end of the excitation coil (12), and the matching network (24) is used to adjust the amplitude and phase of the excitation signal; The detection module (30) comprises: a demodulator (31), a filter (32) and a feedback network (33); The first input end of the demodulator (31) is connected to the second output end of the frequency divider (22), the second input end of the demodulator (31) is connected to the output end of the induction coil (13), and the demodulator (31) is used to adjust the frequency of the induction signal generated by the induction coil (13); The input end of the filter (32) is connected to the output end of the demodulator (31), and the filter (32) is used to filter the frequency-adjusted sensing signal to obtain a measurement value; The input end of the feedback network (33) is connected to the first output end of the filter (32), and the output end of the feedback network (33) is connected to the input end of the induction coil (13). The feedback network (33) is used to input the measured value into the induction coil (13) so that the induction coil (13) generates a feedback magnetic field, wherein the magnetic field strength of the feedback magnetic field is the same as that of the measured magnetic field, and the magnetic field direction of the feedback magnetic field is opposite to that of the measured magnetic field.

2. The fluxgate sensor according to claim 1, characterized in that: The two flux gates (11) included in each flux gate group are spaced apart by the same preset distance.

3. The fluxgate sensor according to claim 1, characterized in that: The two flux gates (11) included in each flux gate group are aligned at both ends.

4. The fluxgate sensor according to claim 1, characterized in that: The wire diameter of the excitation coil (12) is 0.035 mm to 0.1 mm, and the number of turns of the excitation coil (12) is 200 to 2000 turns; The wire diameter of the induction coil (13) is 0.05 mm to 0.2 mm, and the number of turns of the induction coil (13) is 800 to 3000 turns.

5. The fluxgate sensor according to claim 1, characterized in that: The magnetic core (14) has a diameter of 50-300 mm and a length of 10-30 mm.

6. The fluxgate sensor according to claim 1, characterized in that: Also includes: A power module (40), the power module (40) being connected to the excitation module (20) and the detection module (30), the power module (40) being used to supply power to the excitation module (20) and the detection module (30).

7. A working method of a fluxgate sensor according to any one of claims 1 to 6, characterized in that: include: Using the excitation module to generate an excitation signal and a frequency division signal; Using the excitation signal to drive all the excitation coils in the probe, so that the magnetic cores wound with the excitation coils are all in an excitation saturation state; Using all the magnetic cores in the excitation saturation state to make all the induction coils in the probe generate induction signals; Using the detection module to obtain a measurement value according to the frequency division signal and the sensing signal; The detection module is used to input the measured value into all the induction coils in the probe, so that all the induction coils generate a feedback magnetic field with a direction opposite to the measured magnetic field and the same magnetic field strength.

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