Eddy current magnetic field measurement system and method based on fluxgate sensor

Abstract

The invention provides an eddy current magnetic field measurement system and method based on a fluxgate sensor. The eddy current magnetic field measurement system comprises a measurement platform used for placing a measured object, a magnetic variation simulation coil, a sensor assembly, a high-precision constant current source, an eddy current magnetic field tester and a test host. The sensor assembly comprises a first three-axis fluxgate sensor and a second three-axis fluxgate sensor, wherein the first three-axis fluxgate sensor is located in the measuring platform and used for measuring an eddy current magnetic field value generated by a measured object, and the second three-axis fluxgate sensor is located on the periphery of the measuring platform and used for measuring an environment magnetic field value. The beneficial effects of the invention are that the high-precision constant current source inputs the magnetic variation simulation current to the ECMAG12 eddy current magnetic field tester, and after the ECMAG12 eddy current magnetic field tester receives the magnetic variation simulation current, the ECMAG12 eddy current magnetic field tester introduces the magnetic variation simulation current into the induction coil of the first three-axis fluxgate sensor through the adjusting resistor. And therefore, the measurement work of the eddy current magnetic field can be completed, and the measurement precision of the eddy current magnetic field can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship demagnetization, and in particular to a fluxgate sensor-based eddy current magnetic field measurement system and method. Background Art

[0002] Ship degaussing can reduce magnetic field signatures, mitigate the risk of magnetic mine attacks, improve stealth and survivability, ensure navigation safety, and protect the marine environment, possessing significant military and civilian applications. Eddy current magnetic field measurement is a key method for effective degaussing. It accurately captures the magnetic field characteristics generated by a moving ship, providing data support for the degaussing system, optimizing degaussing parameters, and reducing the risk of magnetic mine detection.

[0003] When measuring eddy current magnetic fields, the object being measured is usually placed in a magnetically variable simulation coil. A regularly changing current is then generated in the coil to create a changing magnetic field, which changes the object's magnetic flux and forms an eddy current magnetic field. However, the given changing magnetic field can interfere with the measurement of the eddy current magnetic field. Currently, the main method for measuring eddy current magnetic fields is to use a magnetic sensor placed in a specific position so that it can only measure a given changing magnetic field. The measurement value of this sensor is then subtracted from the measurement value of the magnetic sensor measuring the eddy current magnetic field. However, this method of eliminating the given magnetic field has non-negligible errors and operational difficulties, such as determining the placement of the background sensor. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an eddy current magnetic field measurement system and method based on a fluxgate sensor, so as to solve the problems of non-negligible errors and operational difficulties in the existing eddy current magnetic field measurement technology.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides the following technical solutions:

[0006] A fluxgate sensor-based eddy current magnetic field measurement system includes a measuring platform for placing a measured object, a magnetically variable simulation coil wound on the surface of the measuring platform, a sensor assembly, a high-precision constant current source, an eddy current magnetic field tester, and a test host; wherein the magnetically variable simulation coil is connected to the high-precision constant current source, and the high-precision constant current source is connected to the eddy current magnetic field tester and the test host respectively; the sensor assembly includes a first three-axis fluxgate sensor located in the measuring platform and used to measure the eddy current magnetic field value generated by the measured object, and a second three-axis fluxgate sensor located around the measuring platform and used to measure the ambient magnetic field value; the first three-axis fluxgate sensor and the second three-axis fluxgate sensor are both connected to the eddy current magnetic field tester, and the eddy current magnetic field tester is also connected to the test host.

[0007] In one embodiment of the present invention, the first three-axis fluxgate sensor and the second three-axis fluxgate sensor each include three single-axis fluxgate sensors, the single-axis fluxgate sensor including a shell, a ceramic skeleton provided in the shell, a calibration coil wound around the surface of the ceramic skeleton, the ceramic skeleton including two coil skeletons, a magnetic core provided in each of the two coil skeletons, an excitation coil wound around the surface of one of the coil skeletons, and an induction coil wound around the surface of the other coil skeleton.

[0008] In one embodiment of the present invention, the eddy current and magnetic field tester is an ECMAG12 eddy current and magnetic field tester, which includes a box body, brackets on the left and right sides of the box body, a power indicator light on the front side of the box body, an eddy current measurement function switch, an Ethernet interface located directly below the eddy current measurement function switch and connected to the test host, N sensor interfaces located on the side of the Ethernet interface, a power interface located on the side of the N sensor interfaces, and a magnetic variable analog current input interface located on the side of the power interface and connected to the high-precision constant current source.

[0009] In one embodiment of the present invention, the N sensor interfaces include N-1 first sensor interfaces that can be switched to ordinary magnetic field measurement function and eddy current magnetic field measurement function through the eddy current measurement function switch and are connected to the first three-axis fluxgate sensor, and 1 second sensor interface that is only used for ordinary magnetic field measurement and is connected to the second three-axis fluxgate sensor.

[0010] A fluxgate sensor-based eddy current magnetic field measurement method, based on the fluxgate sensor-based eddy current magnetic field measurement system, includes the following steps: correctly connecting various devices in the fluxgate sensor-based eddy current magnetic field measurement system, and placing the object to be measured in the measurement area within the measurement platform; using a test host to control a high-precision constant current source to output a magneto-variable simulation current to drive a magneto-variable simulation coil to generate a varying magnetic field, while the high-precision constant current source also inputs the magneto-variable simulation current into an eddy current magnetic field tester; the eddy current magnetic field tester calculates eddy current magnetic field values related to the object to be measured by combining the magneto-variable simulation current, the output values of a first three-axis fluxgate sensor, and a second three-axis fluxgate sensor; and the eddy current magnetic field tester sends the calculated eddy current magnetic field values to the test host.

[0011] In one embodiment of the present invention, the eddy current magnetic field tester combines the magneto-variable simulation current, the output values of the first three-axis fluxgate sensor and the second three-axis fluxgate sensor to calculate the eddy current magnetic field value related to the object under test, including: after the eddy current magnetic field tester receives the magneto-variable simulation current, it will introduce the magneto-variable simulation current into the induction coil of the first three-axis fluxgate sensor through the adjustment resistor, so that the artificially applied changing magnetic field can be offset in real time; the first three-axis fluxgate sensor is used to measure the magnetic field value in the measurement platform, and the electrical signal corresponding to the magnetic field value is sent to the eddy current magnetic field tester; at the same time, the second three-axis fluxgate sensor is used to measure the environmental magnetic field value around the measurement platform, and the electrical signal corresponding to the environmental magnetic field value is sent to the eddy current magnetic field tester; the eddy current magnetic field tester will subtract the environmental magnetic field value measured by the second three-axis fluxgate sensor from the magnetic field value measured by the first three-axis fluxgate sensor to obtain the eddy current magnetic field value related to the object under test.

[0012] In one embodiment of the present invention, during the measurement of the eddy current magnetic field generated by the measured object, the magnetic field value within the measurement platform measured by the first three-axis fluxgate sensor is the sum of the eddy current magnetic field value and the ambient magnetic field value.

[0013] As described above, the eddy current magnetic field measurement system and method based on the fluxgate sensor of the present invention have the following beneficial effects: the present invention inputs the magnetic variable simulation current into the ECMAG12 eddy current magnetic field tester through a high-precision constant current source. After the ECMAG12 eddy current magnetic field tester receives the magnetic variable simulation current, it will introduce the magnetic variable simulation current into the induction coil of the first three-axis fluxgate sensor through the adjustment resistor, which can offset the artificially applied changing magnetic field in real time, thereby completing the measurement of the eddy current magnetic field, and solving the problem that the method of eliminating the given magnetic field has non-negligible errors and operational difficulty; the ECMAG12 eddy current magnetic field tester can more accurately compensate for the given changing magnetic field while simplifying the eddy current testing system, thereby improving the accuracy of eddy current magnetic field measurement; and the ECMAG12 eddy current magnetic field tester has a high degree of automatic measurement capability, which can help improve the degree of automation of the eddy current magnetic field measurement system and improve system efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is a schematic diagram of the overall structure of the eddy current magnetic field measurement system based on the fluxgate sensor disclosed in an embodiment of the present invention;

[0015] Figure 2 Shown is a schematic diagram of a measurement platform and a magnetic variation simulation coil in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0016] Figure 3Shown is a schematic diagram of the internal structure of a single-axis fluxgate sensor in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0017] Figure 4 Shown is a front view schematic diagram of an eddy current magnetic field tester in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0018] Figure 5 Shown is a rear view schematic diagram of an eddy current magnetic field tester in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0019] Figure 6 Shown is a physical schematic diagram of an eddy current magnetic field tester in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0020] Figure 7 Shown is a schematic diagram of the principle of an eddy current magnetic field tester in an eddy current magnetic field measurement system based on a fluxgate sensor disclosed in an embodiment of the present invention;

[0021] Figure 8 It shows a schematic diagram of the overall process of the eddy current magnetic field measurement method based on the fluxgate sensor disclosed in an embodiment of the present invention.

[0022] Component number description

[0023] 1. Measuring platform; 2. Measured object; 3. Magnetic variable simulation coil; 4. First three-axis fluxgate sensor; 401. Ceramic bobbin; 4011. Coil bobbin; 402. Calibration coil; 403. Magnetic core; 404. Excitation coil; 405. Induction coil; 5. Second three-axis fluxgate sensor; 6. High-precision constant current source; 7. Eddy current magnetic field tester; 701. Box; 702. Bracket; 703. Power indicator light; 704. Eddy current measurement function switch; 705. Ethernet interface; 706. Sensor interface; 707. Power interface; 708. Magnetic variable simulation current input interface; 8. Test host. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless there is a conflict.

[0025] The first embodiment of the present invention relates to an eddy current magnetic field measurement system based on a fluxgate sensor, see Figure 1, including a measuring platform 1 for placing the object to be measured 2, a magnetically variable simulation coil 3 wound on the surface of the measuring platform 1, a sensor assembly, a high-precision constant current source 6, an eddy current magnetic field tester 7 and a testing host 8; wherein, the magnetically variable simulation coil 3 is connected to the high-precision constant current source 6, and the high-precision constant current source 6 is connected to the eddy current magnetic field tester 7 and the testing host 8 respectively; the sensor assembly includes a first three-axis fluxgate sensor 4 located in the measuring platform 1 and used to measure the eddy current magnetic field value generated by the object to be measured 2 and a second three-axis fluxgate sensor 5 located around the measuring platform 1 and used to measure the ambient magnetic field value, the first three-axis fluxgate sensor 4 and the second three-axis fluxgate sensor 5 are both connected to the eddy current magnetic field tester 7, and the eddy current magnetic field tester 7 is also connected to the testing host 8.

[0026] See also Figure 2 , a variable magnetic field is provided by the magnetic variable simulation coil 3 to simulate the movement of the ship cutting the geomagnetic line: the key to measuring the eddy current magnetic field by magnetic variable simulation is the design of the magnetic variable simulation coil system, that is, the design of the coil system to realize the magnetic variable simulation of the eddy current magnetic field. When designing the magnetic variable simulation coil system, there are several key points: (1) The eddy current magnetic field is generated by the movement of the measured object 2 cutting the geomagnetic line. The geomagnetic field in the small area where the measured object 2 is located can be considered as a uniform magnetic field. Therefore, the designed coil system needs to be able to generate a magnetic field with as high uniformity as possible. Generally speaking, the more coil pairs, the higher the uniformity of the generated magnetic field; (2) The magnetic field value generated by the coil system shall not exceed the range of the eddy current test instrument, that is, the three-axis fluxgate sensor (0~±100000nT) used in the present invention, so the number of coil pairs should not be too many; (3) The ECMAG12 eddy current magnetic field tester needs to introduce current into the magnetic variable simulation coil 3, so the designed coil system needs to have a suitable coil constant (current / magnetic field value); In the present invention, a single-axis magnetic variable simulation coil system is used, which has low installation requirements and is easy to implement.

[0027] See also Figure 3The first three-axis fluxgate sensor 4 and the second three-axis fluxgate sensor 5 each include three single-axis fluxgate sensors. The three single-axis fluxgate sensors share an excitation signal to make the excitation amplitudes of the X, Y, and Z component sensors consistent. The single-axis fluxgate sensor includes a shell, a ceramic skeleton 401 is provided in the shell, a calibration coil 402 is wound around the surface of the ceramic skeleton 401, and the ceramic skeleton 401 includes two coil skeletons 4011. A magnetic core 403 is provided in each of the two coil skeletons 4011, an excitation coil 404 is wound around the surface of one coil skeleton 4011, and an induction coil 405 is wound around the surface of the other coil skeleton 4011. It should be noted that the working principle of the fluxgate sensor is to pass an excitation current of a certain frequency through the excitation coil 404 to magnetize the Permalloy sheet to saturation. After that, the external magnetic field is measured based on the principle that the magnitude of the external magnetic field is proportional to the second harmonic of the induced voltage of the induction coil 405. The fluxgate sensor is a sensitive element of the magnetic field vector. When the direction of the measured magnetic field is parallel to the axis direction of the fluxgate sensor, it is the most sensitive state to the magnetic field strength. When the direction of the magnetic field is perpendicular to the axis direction of the fluxgate sensor, it is the least sensitive state, and the sensor will not detect the existence of the magnetic field at this time. In the present invention, the patented technology of Shanghai Maritime University with independent intellectual property rights, "three-terminal fluxgate sensor, patent number 200510028289.9", is adopted. The sensor can measure the total amount of magnetic field in the environment in real time and comprehensively perceive the magnetic field state of the environment. The fluxgate sensor independently designed and manufactured by Shanghai Maritime University has excellent performance and effectively improves the measurement accuracy of eddy current magnetic field.

[0028] The fluxgate sensor uses Permalloy 403 produced by the Iron and Steel Research Institute as the magnetic core. Permalloy is a nickel-iron magnetic alloy with a nickel content of about 80% and an iron content of about 20%. The Permalloy grade is 1JXX, where J stands for "precision alloy" and "1" stands for soft magnetism. The following numbers are serial numbers, usually indicating the nickel content in the alloy, such as 1J50, 1J86, etc. It has high magnetic permeability, low coercive force, near-zero magnetostriction and significant anisotropic magnetoresistance, which can effectively improve the performance of the fluxgate sensor and withstand strong magnetic shocks, improving the system's resistance to test after being subjected to large magnetic field shocks. The accuracy of the description of the spatial distribution characteristics of the target magnetic field is determined. The heat treatment process is the main factor affecting the magnetic properties of Permalloy, and its performance is mainly affected by factors such as temperature, holding time annealing mode, and cooling rate. The support frame of the fluxgate sensor adopts a 95 alumina ceramic frame with a length of 18 mm. The excitation coil is evenly wound on the ceramic frame. The two excitation coils 404 A and B are bonded together. The excitation coils 404 are connected in series, and then the measurement coil is evenly wound on the outer layer of the bonded excitation coils 404. Permalloy is inserted into the center hole of the ceramic frame 401 to make a runway-type fluxgate sensor.

[0029] For the entire eddy current magnetic field measurement system, the performance (accuracy and stability) of the constant current source plays a vital role. According to the use requirements of the eddy current measurement system, the high-precision constant current source 6 used needs to meet the following requirements: (1) Current output range: ±1.2A; (2) Resolution: 10μA; (2) Output power: ≤48W; (2) Load range: 0~40Ω; (2) Optimal load: >20Ω; (2) Effective output voltage: ≤40V; (2) Accuracy: ±(0.015% setting value +20μA)@1000mA; (2) Noise / ripple: 20μARMS typical value@1000mA; (2) Output impedance: >100MΩ; (2) Stability: better than ±0.01%@1000mA; (2) Control interface: RS232 / RS485 / Ethernet.

[0030] See also Figures 4 to 6 The eddy current magnetic field tester 7 is an ECMAG12 eddy current magnetic field tester, which includes a box body 701, brackets 702 on the left and right sides of the box body 701, a power indicator light 703 on the front side of the box body 701, and an eddy current measurement function switch 704, an Ethernet interface 705 located directly below the eddy current measurement function switch 704 and connected to the test host 8, N sensor interfaces 706 located on the side of the Ethernet interface 705, a power interface 707 located on the side of the N sensor interfaces 706, and a magnetic variable analog current input interface 708 located on the side of the power interface 707 and connected to the high-precision constant current source 6; the N sensor interfaces 706 include N-1 sensors that can be switched to ordinary magnetic field measurement function and eddy current magnetic field measurement function by the eddy current measurement function switch 704 and connected to the first three-axis fluxgate sensor 4. A sensor interface and a second sensor interface for ordinary magnetic field measurement only and connected to the second three-axis fluxgate sensor 5; it should be noted that the independently designed ECMAG12 eddy current magnetic field tester in the present invention is used for multi-channel eddy current magnetic field measurement; the power supply voltage of the power supply interface 707 is +24V, and the supply current is less than 500mA; and in this embodiment, N is 12, that is, there are 12 channels of the three-axis fluxgate sensor, 11 of which can be switched to ordinary magnetic field measurement function and eddy current magnetic field measurement function through the eddy current measurement function switch, and the 12th channel is only used for ordinary magnetic field measurement (ambient magnetic field measurement), so the present invention can simultaneously measure the eddy current magnetic field of the object 2 under test in 11 measuring platforms 1; the magnetic field measurement accuracy of the eddy current magnetic field tester is 1nT, the measurement range is ±10000nT, and the stability is ≤5nT / 2h;

[0031] It can also be said that the magnetic field value measured by the first three-axis fluxgate sensor 4 (represented by the current generated by the induction coil) is the sum of the eddy current magnetic field value, the artificially applied changing magnetic field and the ambient magnetic field. In order to accurately measure the eddy current magnetic field, the artificially applied magnetic field in the measurement result must be eliminated, because the ambient magnetic field is relatively easy to measure, and the ambient magnetic field has little effect on the measured eddy current magnetic field value, so the subsequent direct elimination of the error in the measured eddy current magnetic field is very small; therefore, the magnetic variable simulation current is connected through the magnetic variable simulation current input interface 708 of the ECMAG12 eddy current magnetic field tester, and the eddy current magnetic field tester 7 introduces this current into the induction coil of each eddy current measurement sensor through the adjustment resistor, which can offset the artificially applied changing magnetic field in real time and complete the eddy current magnetic field measurement work; there are also two levels of compensation for the given changing magnetic field, the first level of compensation is used for coarse adjustment, and this compensation coefficient is related to the coil constant of the magnetic variable simulation coil 3, and the second level is used for fine adjustment, and this compensation coefficient is related to the sensitivity parameters of each magnetic measurement channel. The principle of the eddy current magnetic field tester 7 compensating for the given changing magnetic field is shown in the attached Figure 7 .

[0032] Since the subsequent processing method of the eddy current magnetic field is mainly determined by the needs of the user, the present invention does not provide specific control software, but only provides an Ethernet communication protocol for the ECMAG12 eddy current magnetic field tester. This protocol is formulated in full consideration of the use scenarios and needs of the eddy current magnetic field tester, aiming to help users use it quickly and also provide users with sufficient secondary development space; the communication protocol of the ECMAG12 eddy current magnetic field tester is described as follows: Communication parameters: The ECMAG12 eddy current magnetic field tester and the test host 8 communicate via Ethernet, and the communication The protocol is UDP. The default IP address of the tester is 192.168.0.12, the default port is 1200, the default gateway is 192.168.0.128, and the default subnet mask is 255.255.255.0. The user only needs to set the IP address of the test host to the same network segment as the tester to communicate with it. For example, the IP address of the test host is 192.168.0.10, the port is 528, the gateway is 192.168.0.128, and the subnet mask is 255.255.255.0.

[0033] The second embodiment of the present invention relates to a method for measuring eddy current magnetic field based on a fluxgate sensor. The method uses an eddy current magnetic field measurement system based on a fluxgate sensor. The process is as follows: Figure 8 As shown, the details are as follows:

[0034] Step 101 : correctly connect all devices in the eddy current magnetic field measurement system based on the fluxgate sensor, and place the object to be measured 2 in the measurement area of the measurement platform 1 .

[0035] Step 102 , use the test host 8 to control the high-precision constant current source 6 to output a magnetic variable simulation current to drive the magnetic variable simulation coil 3 to generate a changing magnetic field. At the same time, the high-precision constant current source 6 also inputs the magnetic variable simulation current to the eddy current magnetic field tester 7 .

[0036] In step 103, after receiving the magnetically variable simulation current, the eddy current magnetic field tester 7 introduces the magnetically variable simulation current into the induction coil of the first three-axis fluxgate sensor 4 through the adjustment resistor, thereby offsetting the artificially applied changing magnetic field in real time.

[0037] Step 104, use the first three-axis fluxgate sensor 4 to measure the magnetic field value within the measuring platform 1, and send the electrical signal corresponding to the magnetic field value to the eddy current magnetic field tester 7; at the same time, use the second three-axis fluxgate sensor 5 to measure the ambient magnetic field value around the measuring platform 1, and send the electrical signal corresponding to the ambient magnetic field value to the eddy current magnetic field tester 7.

[0038] Specifically, during the measurement of the eddy current magnetic field generated by the measured object 2 , the magnetic field value within the measurement platform 1 measured by the first three-axis fluxgate sensor 4 is the sum of the eddy current magnetic field value and the ambient magnetic field value.

[0039] In step 105 , the eddy current magnetic field tester 7 subtracts the ambient magnetic field value measured by the second three-axis fluxgate sensor 5 from the magnetic field value measured by the first three-axis fluxgate sensor 4 , thereby obtaining an eddy current magnetic field value related to the object 2 under test.

[0040] In step 106 , the eddy current magnetic field tester 7 sends the calculated eddy current magnetic field value to the test host 8 .

[0041] Specifically, the three-axis fluxgate sensor is used to measure the eddy current magnetic field; the magnetic variable simulation coil 3 is used to simulate the changing magnetic field; the high-precision constant current source 6 is used to generate an accurate and stable magnetic variable simulation current to drive the magnetic variable simulation coil 3 to generate a changing magnetic field; the ECMAG12 eddy current magnetic field tester combines the magnetic variable simulation current and the output value of the three-axis fluxgate sensor to solve the eddy current magnetic field, thereby eliminating the given magnetic field in the measurement value; the high-precision constant current source 6 and the ECMAG12 eddy current magnetic field tester both have communication interfaces, which provide convenience for the realization of an automated eddy current testing system; the ECMAG12 eddy current magnetic field tester transmits the settled eddy current magnetic field value to the test host 8 through the Ethernet communication interface.

[0042] To sum up, the present invention inputs the magnetic variable simulation current into the ECMAG12 eddy current magnetic field tester through a high-precision constant current source 6. After receiving the magnetic variable simulation current, the ECMAG12 eddy current magnetic field tester will introduce the magnetic variable simulation current into the induction coil 405 of the first three-axis fluxgate sensor 4 through an adjusting resistor, which can offset the artificially applied changing magnetic field in real time, thereby completing the measurement of the eddy current magnetic field, solving the problem of non-negligible errors and operational difficulty in the method of eliminating the given magnetic field; the ECMAG12 eddy current magnetic field tester can more accurately compensate for the given changing magnetic field while simplifying the eddy current testing system, thereby improving the accuracy of eddy current magnetic field measurement; and the ECMAG12 eddy current magnetic field tester has a high degree of automatic measurement capability, which can help improve the degree of automation of the eddy current magnetic field measurement system and improve system efficiency.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any equivalent modifications or variations made by persons skilled in the art without departing from the spirit and technical concepts disclosed herein shall be encompassed by the claims of the present invention.

Claims

1. An eddy current magnetic field measurement system based on a fluxgate sensor, characterized in that: The device comprises a measuring platform (1) for placing a measured object (2), a magnetic variable simulation coil (3) wound on the surface of the measuring platform (1), a sensor component, a high-precision constant current source (6), an eddy current magnetic field tester (7), and a test host (8); The magnetic variable simulation coil (3) is connected to the high-precision constant current source (6), and the high-precision constant current source (6) is respectively connected to the eddy current magnetic field tester (7) and the test host (8). The sensor assembly includes a first three-axis fluxgate sensor (4) located in the measuring platform (1) and used to measure the eddy current magnetic field value generated by the measured object (2) and a second three-axis fluxgate sensor (5) located around the measuring platform (1) and used to measure the environmental magnetic field value. The first three-axis fluxgate sensor (4) and the second three-axis fluxgate sensor (5) are both connected to the eddy current magnetic field tester (7), and the eddy current magnetic field tester (7) is also connected to the test host (8).

2. The eddy current magnetic field measurement system based on a fluxgate sensor according to claim 1, characterized in that: The first three-axis fluxgate sensor (4) and the second three-axis fluxgate sensor (5) both comprise three single-axis fluxgate sensors. The single-axis fluxgate sensors comprise a shell, a ceramic skeleton (401) is provided in the shell, a calibration coil (402) is wound around the surface of the ceramic skeleton (401), the ceramic skeleton (401) comprises two coil skeletons (4011), a magnetic core (403) is provided in each of the two coil skeletons (4011), an excitation coil (404) is wound around the surface of one of the coil skeletons (4011), and an induction coil (405) is wound around the surface of the other coil skeleton (4011).

3. The eddy current magnetic field measurement system based on a fluxgate sensor according to claim 1, characterized in that: The eddy current magnetic field tester (7) is an ECMAG12 eddy current magnetic field tester, comprising a box body (701), brackets (702) being provided on the left and right sides of the box body (701), a power indicator light (703) being provided on the front side of the box body (701), an eddy current measurement function switch (704), an Ethernet interface (705) located directly below the eddy current measurement function switch (704) and connected to the test host (8), N sensor interfaces (706) located on the side of the Ethernet interface (705), a power interface (707) located on the side of the N sensor interfaces (706), and a magnetic variable analog current input interface (708) located on the side of the power interface (707) and connected to the high-precision constant current source (6).

4. The eddy current magnetic field measurement system based on a fluxgate sensor according to claim 3, characterized in that: The N sensor interfaces (706) include N-1 first sensor interfaces that can be switched to a common magnetic field measurement function and an eddy current magnetic field measurement function via the eddy current measurement function switch (704) and are connected to the first three-axis fluxgate sensor (4), and one second sensor interface that is only used for common magnetic field measurement and is connected to the second three-axis fluxgate sensor (5).

5. A method for measuring eddy current magnetic field based on a fluxgate sensor, characterized in that: The eddy current magnetic field measurement system based on the fluxgate sensor according to any one of claims 1 to 4 comprises the following steps: Correctly connect the various devices in the eddy current magnetic field measurement system based on the fluxgate sensor, and place the object to be measured (2) at the measurement area within the measurement platform (1); The test host (8) is used to control the high-precision constant current source (6) to output a magnetic variable simulation current to drive the magnetic variable simulation coil (3) to generate a variable magnetic field. At the same time, the high-precision constant current source (6) also inputs the magnetic variable simulation current into the eddy current magnetic field tester (7); The eddy current magnetic field tester (7) calculates the eddy current magnetic field value related to the object to be measured (2) by combining the magnetic variable simulation current, the output values of the first three-axis fluxgate sensor (4) and the second three-axis fluxgate sensor (5); The eddy current magnetic field tester (7) sends the calculated eddy current magnetic field value to the test host (8).

6. The eddy current magnetic field measurement method based on a fluxgate sensor according to claim 5, characterized in that: The eddy current magnetic field tester (7) calculates the eddy current magnetic field value related to the object to be measured (2) by combining the magnetic variable simulation current, the output values of the first three-axis fluxgate sensor (4) and the second three-axis fluxgate sensor (5), including: After receiving the magnetically variable simulation current, the eddy current magnetic field tester (7) introduces the magnetically variable simulation current into the induction coil of the first three-axis fluxgate sensor (4) through the adjustment resistor, thereby offsetting the artificially applied changing magnetic field in real time; A first three-axis fluxgate sensor (4) is used to measure a magnetic field value within the measuring platform (1), and an electrical signal corresponding to the magnetic field value is sent to an eddy current magnetic field tester (7); and a second three-axis fluxgate sensor (5) is used to measure an environmental magnetic field value around the measuring platform (1), and an electrical signal corresponding to the environmental magnetic field value is sent to the eddy current magnetic field tester (7); The eddy current magnetic field tester (7) subtracts the environmental magnetic field value measured by the second three-axis fluxgate sensor (5) from the magnetic field value measured by the first three-axis fluxgate sensor (4), thereby obtaining an eddy current magnetic field value related to the object under test (2).

7. The eddy current magnetic field measurement method based on a fluxgate sensor according to claim 6, characterized in that: During the measurement of the eddy current magnetic field generated by the measured object (2), the magnetic field value within the measuring platform (1) measured by the first three-axis fluxgate sensor (4) is the sum of the eddy current magnetic field value and the ambient magnetic field value.

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