CN114518406A

CN114518406A - Differential eddy current resonance detection sensor and system

Info

Publication number: CN114518406A
Application number: CN202210173255.2A
Authority: CN
Inventors: 高斌; 白宗璞; 杨雨沛; 谌梁; 罗飞; 张勇; 姜世强
Original assignee: Sichuan Deyuan Pipeline Technology Co ltd
Current assignee: Sichuan Deyuan Pipeline Technology Co ltd
Priority date: 2022-02-24
Filing date: 2022-02-24
Publication date: 2022-05-20

Abstract

The invention discloses a differential eddy current resonance detection sensor and a differential eddy current resonance detection system, which belong to the technical field of nondestructive detection, and comprise an excitation coil and a receiving coil which are arranged in a coupling manner, wherein the receiving coil is connected with a first resonance capacitor in parallel, and the excitation coil is connected with a second resonance capacitor in parallel, so that an excitation loop and a detection loop are respectively in a resonance state, the mutual inductance of the excitation coil and the receiving coil is enhanced, the coil voltage when a defect is detected is enhanced, and further, the related defect information of a detected piece is detected, and the defect detection capability is improved. Furthermore, the coupling relation between the exciting coil and the detecting coil is changed by connecting the exciting coil and the receiving coil in parallel with the resonant capacitor, the mutual inductance between the coils is increased, the optimal excitation frequency is reduced, the skin depth of the eddy current is increased, and the detection capability of deep defects is improved.

Description

Differential eddy current resonance detection sensor and system

Technical Field

The invention relates to the technical field of nondestructive testing, in particular to a differential eddy current resonance testing sensor and a differential eddy current resonance testing system.

Background

Pipeline transportation is considered one of the safest and economical means of transportation. However, as with all engineering equipment, there are safety issues and crack defects tend to occur over time during use of the pipe. In the past decades, a large number of safety accidents are caused by pipeline faults all over the world, and in order to avoid the problems, a large amount of manpower and financial resources are invested in all countries all over the world to detect the operation state of the pipeline in real time and discover the defects of the pipeline in real time. At present, the in-pipeline detection method is widely applied to pipeline integrity evaluation, becomes an important pre-control means for guaranteeing the safe transportation of oil and gas pipelines, and has great significance for eliminating pipeline risk factors. The detection method in the pipeline can effectively evaluate the running state of the pipeline by virtue of better qualitative and quantitative analysis capability of the defects, and indirectly reduces the occurrence rate of pipeline explosion accidents.

In addition, the existing pipeline nondestructive testing means such as magnetic leakage method, ultrasonic testing, alternating electromagnetic field, eddy current testing and the like have the following defects: the magnetic flux leakage detection has poor detection effect on the non-ferromagnetic pipeline, the weight of the instrument is large, and the detection efficiency is low; the ultrasonic detection needs a coupling agent, the detection speed is extremely low, the detection time is long, a certain near-field blind area exists, and the detection is easy to miss; the detection effect of the alternating electromagnetic field detection technology on the lift-off effect is poor, and the magnetic yoke is not easy to place in the pipeline; the existing eddy current detection can not effectively separate the defect information from the detection signal, and the defect detection performance needs to be improved.

Disclosure of Invention

The invention aims to solve the problems that the existing eddy current detection cannot effectively separate the defect information from the detection signal and the defect detection performance needs to be improved, and provides a differential eddy current resonance detection sensor and a differential eddy current resonance detection system.

The purpose of the invention is realized by the following technical scheme: a differential eddy current resonance detection sensor comprises an excitation coil and a receiving coil which are arranged in a coupling mode, wherein the excitation coil and the receiving coil are formed by winding copper wires, and the receiving coil is connected with a first resonance capacitor in parallel.

In one example, the receiver coil includes a plurality of layers of receiver sub-coils connected in series.

In one example, the receiver sub-coil is a PCB rectangular coil.

In one example, the excitation coil is connected in parallel with a second resonant capacitor.

In one example, the excitation coil is a differential coil.

In one example, the excitation coil is a PCB differential coil.

In one example, the excitation coil is a PCB rectangular differential coil.

In an example, the first resonant capacitance and/or the second resonant capacitance is an adjustable capacitance.

In one example, the excitation coil is coaxially coupled to the receiving coil.

It should be further noted that the technical features corresponding to the above examples can be combined with each other or replaced to form a new technical solution.

The invention also comprises a differential eddy current resonance detection system, which comprises the detection sensor formed by any one or more of the above examples, a signal generator and a back-end data processing unit, wherein the signal generator, the detection sensor and the back-end data processing unit are sequentially connected.

Compared with the prior art, the invention has the beneficial effects that:

1. in one example, the receiving coil and the first resonant capacitor are connected in parallel to enable the receiving coil and the first resonant capacitor to reach a resonant state, signal voltage when the defect is detected is increased, micro change information can be better reflected, the defect is accurately separated from the detection signal, and the defect detection performance is improved.

2. In one example, the plurality of layers of receiver sub-coils connected in series can not only improve the detection sensitivity and reduce the optimal detection frequency, but also effectively reduce the requirement on the excitation signal. Meanwhile, the coil array created by a plurality of receiver sub-coils is adopted, so that the detection time can be reduced.

3. In one example, the receiver sub-coils are PCB rectangular coils, the rectangular coils are easier to splice and combine when being tiled into a coil array, and the sensitivity to the edge effect is lower; the PCB coil has the characteristics of small volume and high sensitivity to surface defects, and meanwhile, the sensitivity to the defects is high due to small effective lift-off amount, so that the PCB coil has wide application prospect in the field of eddy current detection; further, the PCB coil is easy to directly manufacture and permanently fixed on the detection robot; in addition, the PCB coil has sufficient flexibility, and the coil is allowed to be consistent with the surface of the pipeline to be detected, so that the detection sensor has a very wide application prospect in the aspect of detecting the geometric shape of a complex surface.

4. In one example, the excitation coil and the second resonance capacitor are connected in parallel to form a resonance state, so that the eddy current strength generated on the tested piece is enhanced, the defect disturbance causes larger secondary magnetic field change, the signal voltage when the defect is detected is increased, and the defect detection performance is further improved. Furthermore, the coupling relation between the exciting coil and the detecting coil is changed by connecting capacitors in parallel between the exciting coil and the receiving coil, the mutual inductance between the coils is increased, the optimal excitation frequency is reduced, the skin depth of eddy current is increased, and the detection capability of deep defects is improved.

5. In one example, the exciting coils are differential coils, uniform eddy current can be formed in the central area of the coil, and the middle eddy current area can generate obvious eddy current change when the defect is detected, so that the magnetic field is changed, and the defect part can be distinguished conveniently.

6. In one example, the exciting coil is a PCB coil, so that the exciting coil and the receiving coil are integrated into a whole, and nondestructive detection of the tested piece is facilitated.

7. In one example, rectangular coils are easier to distinguish between defects of different shapes than other shaped coils.

8. In one example, the resonant capacitor is an adjustable capacitor, and the resonant capacitor and the exciting coil or the receiving coil are convenient to be in a resonant state by changing the capacitance value of the capacitor.

9. In one example, the exciting coil and the receiving coil are coaxially coupled, so that the energy transmission efficiency can be improved to the maximum extent, and the sensitivity of the detection sensor can be improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention.

FIG. 1 is a schematic diagram of a receiver coil according to an example of the present invention;

FIG. 2 is a schematic diagram of a first layer of receiver sub-coils in accordance with an example of the present invention;

FIG. 3 is a schematic view of a second layer receiver coil configuration in accordance with an example of the present invention;

FIG. 4 is a schematic diagram of a third layer receiver sub-coil configuration in accordance with an example of the present invention;

FIG. 5 is a schematic view of a fourth layer receiver coil structure in accordance with an example of the present invention;

FIG. 6 is a schematic diagram of an excitation coil configuration in accordance with an example of the present invention;

FIG. 7 is a schematic diagram of a first resonant capacitor according to an example of the present invention;

FIG. 8 is a schematic diagram of a second resonant capacitor according to an example of the present invention;

FIG. 9 is a block diagram of a detection system in accordance with an example of the present invention;

FIG. 10 is a graph showing a comparison of the detection signals of different sizes of ferromagnetic X80 slab before and after the resonant capacitance introduced by the detection sensor of the present invention in accordance with one embodiment of the present invention;

FIG. 11 is a comparison graph of the detection signals of different sizes of defects on a ferromagnetic X80 flat plate before and after the sensor of the present invention introduces a resonant capacitor in another example of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that directions or positional relationships indicated by "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like are directions or positional relationships described based on the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected" and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

Furthermore, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In one example, a differential eddy current resonance inspection sensor is used for non-destructive inspection of a piece under test, such as for inspection of pipe defects. The transformer comprises an exciting coil and a receiving coil which are arranged in a coupling mode, wherein the exciting coil and the receiving coil are formed by winding copper wires, and the receiving coil is connected with a first resonant capacitor c1 in parallel. Specifically, the coupling setting means that the exciting coil generates an alternating magnetic field under the drive of an alternating current exciting signal, and a detection signal carrying the defect information of the tested piece is coupled to the receiving coil through electromagnetic coupling. The exciting coil and the receiving coil are round coils or rectangular coils formed by winding copper wires. The capacitance value of the first resonant capacitor c1 is selected according to the inductance value of the receiving coil, so that the first resonant capacitor c1 and the receiving coil can reach a resonant state, the signal voltage when the defect is detected is increased, the background noise of the acquired detection signal (including the defect information of the detected piece) is reduced, the micro change information, namely the disturbance information of the defect, can be better reflected, the defect is accurately separated from the detection signal, and the defect detection performance is improved.

In one example, as shown in fig. 1, the receiving coil includes a plurality of layers of receiver sub-coils connected in series in the vertical direction, and preferably, the receiver sub-coils of the respective layers are coaxially arranged. As a preferred embodiment, the receiving coil includes four layers of receiving sub-coils, specifically, a first layer of receiving sub-coil as shown in fig. 2, a second layer of receiving sub-coil as shown in fig. 3, a third layer of receiving sub-coil as shown in fig. 4, and a fourth layer of receiving sub-coil as shown in fig. 5, where the first layer of receiving sub-coil and the fourth layer of receiving sub-coil are respectively provided with an input port input1 and an output port output1, and are connected in parallel with the first resonant capacitor c1 through two ports. Furthermore, the receiving coil is printed on the PCB, via holes via1, via2 and via3 are arranged on the PCB to realize the connection between the four layers of receiving sub-coils, and two interfaces input1 and output1 are connected with the first resonant capacitor c 1. As shown in fig. 2, one end of each of the two ends of the first layer of receiver sub-coil is connected to the interface input1, and the other end is connected to the via hole via 2; as shown in fig. 3, one end of the second layer receiver sub-coil is connected with the first layer receiver sub-coil through a via hole via2, and the other end is connected with a via hole via 3; as shown in fig. 4, one end of the third layer receiver sub-coil is connected with the second layer receiver sub-coil through a via hole via3, and the other end is connected to a via hole via 1; as shown in fig. 5, one end of the fourth layer receiver sub-coil is connected with the third layer receiver sub-coil through a via hole via1, and the other end is connected with an interface output 1. In this example, the receiver sub-coils connected in series in multiple layers can not only improve the detection sensitivity, but also reduce the optimal detection frequency, and can effectively reduce the requirement for excitation signals. Meanwhile, the coil array created by a plurality of receiver sub-coils is adopted, so that the detection time can be reduced.

In one example, the receiver sub-coil is a PCB rectangular coil. The rectangular coils are easier to splice and combine when being tiled into a coil array, and the sensitivity to the edge effect is lower; the PCB coil has the characteristics of small volume and high sensitivity to surface defects, and meanwhile, the sensitivity to the defects is high due to small effective lift-off amount, so that the PCB coil has wide application prospect in the field of eddy current detection; further, the PCB coil is easy to directly manufacture and permanently fixed on the detection robot; in addition, the PCB coil has sufficient flexibility, and the coil is allowed to be consistent with the surface of the pipeline to be detected, so that the detection sensor has a very wide application prospect in the aspect of detecting the geometric shape of a complex surface.

In one example, the excitation coil is connected in parallel with a second resonant capacitor c2, and preferably, the second resonant capacitor c2 is disposed close to the signal generator, that is, the output end of the signal generator is connected to the second resonant capacitor c2 and the excitation coil in turn. Through parallelly connected second resonance electric capacity c2 at exciting coil, make exciting coil and second resonance electric capacity c2 reach the resonance state, strengthened the eddy current intensity that produces on the piece of being tested, make the defect disturbance cause bigger secondary magnetic field to change, increased the signal voltage when detecting the defect, further promoted defect detection performance. Furthermore, the coupling relation between the exciting coil and the detecting coil is changed by connecting capacitors in parallel with the exciting coil and the receiving coil, the mutual inductance between the exciting coil and the receiving coil is increased, the optimal excitation frequency is reduced, the skin depth of eddy current is increased, the voltage (detection signal) of the receiving coil is enhanced finally, and the detection capability of deep defects is improved.

In one example, the exciting coils are differential coils, uniform eddy current can be formed in the central area of the coil, and the middle eddy current area can generate obvious eddy current change when the defect is detected, so that the magnetic field is changed, and the defect part can be distinguished conveniently.

In one example, the exciting coil is a PCB differential coil, and the receiving coil is a PCB coil, so that the exciting coil and the receiving coil are integrated into a whole, nondestructive detection on a tested piece is facilitated, and meanwhile, the detection performance of the sensor can be ensured.

In one example, the excitation coil is a PCB rectangular differential coil, which is easier to distinguish between defects of different shapes than other shaped coils. More specifically, as shown in fig. 6, the exciting coil includes two PCB rectangular differential coils symmetrically arranged to generate more uniform eddy current under the action of the exciting signal; the two PCB rectangular differential coils are connected end to end respectively, so that an input interface input2 and an output interface output2 are led out, two ends of a second resonant capacitor c2 are connected to an input interface input2 and an output interface output2 respectively, and a first resonant capacitor c1 is connected to the exciting coil in parallel.

In an example, as shown in fig. 7, the first resonant capacitor c1 is an adjustable capacitor, one end of the first resonant capacitor c1 leads out two interfaces c1 and input0, and the other end leads out two interfaces c2 and output 0; the interfaces c1 and c2 of the first resonant capacitor c1 are connected to the ports input1 and output1 of the receiving coil, and the interfaces input0 and output0 of the first resonant capacitor c1 are connected to the rear-end data processing unit. As shown in fig. 8, the second resonant capacitor c2 is an adjustable capacitor, two interfaces c3 and input3 are led out from one end of the second resonant capacitor c2, and two interfaces c4 and output3 are led out from the other end of the second resonant capacitor c 2; the interfaces input3 and output3 of the second resonant capacitor c2 are connected to a signal generator as an excitation signal source, and the interfaces c3 and c4 of the second resonant capacitor c2 are connected to the ports input2 and output2 of the excitation coil. In this example, the capacitance values of the two resonant capacitors are in the range of 0-120pF, and the resonant capacitor and the exciting coil or the receiving coil are conveniently brought into a resonant state by changing the capacitance values of the two resonant capacitors. As an option, the surface mount capacitor can be replaced after the capacitance value of the resonant capacitor is determined, so that the resonant capacitor is favorably integrated with the exciting coil and the receiving coil respectively, the defect detection performance is improved, and the defect detection method is easy to realize.

In one example, the excitation coil and the receiving coil are coaxially coupled, that is, the excitation coil and the receiving coil are located on the same central axis, and preferably, the excitation coil and the receiving coil have an optimal coupling coefficient, so that the energy transmission efficiency can be improved to the maximum extent, and the sensitivity of the detection sensor can be improved.

Combining the above multiple examples to obtain the preferred example of the present application, where the excitation coil includes two PCB rectangular differential coils symmetrically disposed, and a second resonant capacitor c2 is connected in parallel; the receiving coil comprises four layers of receiving sub-coils connected in series, the receiving sub-coils are PCB rectangular coils, the receiving coils are connected with a first resonant capacitor c1 in parallel, and the exciting coil and the receiving coils are arranged and packaged with the optimal coupling coefficient to obtain the optimal detection sensor. When the tested piece has a defect, the flow direction of the eddy current on the tested piece can be changed, so that the voltage amplitude or the phase of the receiving coil is changed, and the added adjustable capacitor respectively enables the excitation loop and the detection loop to reach a resonance state by adjusting the capacitance value of the capacitor, increases the mutual inductance of the excitation coil and the receiving coil, increases the coil voltage when the defect is detected, and further detects the related defect information of the tested piece and improves the defect detection capability.

The invention also comprises a differential eddy current resonance detection system, which comprises a detection sensor formed by any example or a plurality of examples, a signal generator and a back-end data processing unit, wherein the signal generator, the detection sensor and the back-end data processing unit are sequentially connected. Specifically, the back-end data processing unit includes a signal processing module and an upper computer connected in sequence, and at this time, as shown in fig. 9, the signal generator, the second resonant capacitor c2, and the excitation coil are connected in sequence, and the receiving coil, the first resonant capacitor c1, the signal processing module, and the PC are connected in sequence. The signal processing module is an FPGA, and the upper computer is used for analyzing detection information fed back by the detection sensor so as to judge whether the pipeline has defects. As an option, the detection system further comprises a control management unit for information storage; in this example, the control management unit is an ARM processor, and the FPGA is bidirectionally connected to the upper computer through the ARM processor.

As a preferred example, the system further includes a first signal conditioning module and a second signal conditioning module, the first signal conditioning module includes a first signal amplification sub-module, and the output end of the signal generator is connected to the first signal amplification sub-module; the second signal conditioning module comprises a second signal amplification module and an analog-to-digital conversion submodule which are connected in sequence, the receiving coil is connected with the second signal amplification module, and the analog-to-digital conversion submodule is connected with the signal processing module. Specifically, the digital-to-analog conversion sub-module (analog-to-digital conversion sub-module) is specifically an ADC chip, the signal amplification sub-module is specifically a power amplifier chip or an operational amplifier chip, and pin connection between the chips is specifically implemented according to a chip manual, which belongs to common general knowledge of those skilled in the art and is not described herein again.

To further illustrate the inventive concept of the present invention, the working principle of the detection system of the present invention will now be explained:

the detection sensor in the detection system is arranged on a tested piece, the system is electrified to start working, the signal generator generates a sine wave excitation signal, the sine wave excitation signal is amplified by the power amplifier (the first signal amplification submodule) and is applied to the excitation coil, the excitation coil generates a primary magnetic field under the drive of the excitation signal, the primary magnetic field generates an eddy current on the surface of the tested piece (pipeline), the flow direction of the eddy current at a defect is changed, a secondary magnetic field generated by the eddy current is changed due to the change of the eddy current, the amplitude and the phase of the receiving coil are further detected to be changed by detecting the change of the magnetic flux of the receiving coil, therefore, the induced voltage generated by the primary magnetic field and the induced voltage (the feedback detection signal) generated by the secondary magnetic field are amplified by the operational amplifier (the second signal amplification submodule) and are transmitted to the signal processing module after being converted by the ADC chip, the signal processing module transmits the fed-back detection signal to an upper computer, and the upper computer extracts the amplitude value and the phase value of the detection signal and obtains the amplitude value and the phase change of the detection signal. Furthermore, a second resonance capacitor c2 connected in parallel with the excitation coil resonates with the excitation inductance coil by adjusting the capacitance value, so that the voltage acting on the excitation coil is increased, the eddy current intensity generated on the test piece is increased, the disturbance of the defect can cause greater change of a secondary magnetic field, and the signal voltage when the defect is detected is increased; further, the first resonant capacitor c1 connected in parallel with the receiving coil forms a resonant circuit with the detection inductor coil, directly increasing the signal voltage when a defect is detected. Meanwhile, the capacitors respectively connected with the exciting coil and the receiving coil in parallel increase the inductance of the exciting coil and the receiving coil, further increase the mutual inductance between the coils, finally increase the voltage of the receiving coil and improve the defect detection performance.

To further illustrate the technical effects of the present application, a comparison graph of detection signals of the detection sensor with defects of different sizes in the middle of a ferromagnetic X80 flat plate before and after two resonant capacitors are introduced is provided. Specifically, in the detection process, the lift-off value of the detection sensor and the tested piece is 5mm, the moving speed is 30mm/s, and the detection result is processed to obtain a detection signal diagram as shown in fig. 10, wherein the abscissa in the diagram is the number of points in direct proportion to the detection distance, and the ordinate is the signal amplitude and has the unit of mV. When the detection sensor passes through a non-defective position, the amplitude of the detection signal is unchanged, when the detection sensor passes through a defective position, the amplitude of the detection signal is changed, the changed amplitude is related to the size of the defect, and in the detection, when the width, the depth and the area of the defect are increased, the change of the amplitude of the defect is correspondingly increased. Wherein, the diagrams (a), (b), (c) and (d) are the detection schematic diagrams without introducing two resonance capacitors, the diagrams (e), (f), (g) and (h) are the detection schematic diagrams with introducing two resonance capacitors, and the diagrams (a) and (e) are mutually referred and are the diagrams of rectangular defect detection signals with different widths;

FIGS. 10(b) and (f) are diagrams of rectangular defect detection signals for different depths, with reference to each other; FIGS. 10(c) and (g) are diagrams of circular defect detection signals for different areas, which are mutually referred to; FIGS. 10(d) and (h) are diagrams of rectangular defect detection signals for different directions, referring to each other. It can be seen from the results in the figure that after two resonant capacitors are introduced, the variation amplitude of the defect is obviously increased, and then the defect signal can be separated from the detection signal more accurately, and the detection performance is improved.

Further, the detection sensor of the invention is utilized to compare detection signals of defects with different shapes in the middle of a ferromagnetic X80 flat plate before and after the introduction of a resonance capacitor. Specifically, in the detection process, the lift-off value of the detection sensor and the tested piece is 5mm, the moving speed is 30mm/s, and the detection result is processed to obtain a detection signal diagram shown in fig. 11, wherein the abscissa in the diagram is the number of points in direct proportion to the detection distance, and the ordinate is the signal amplitude and the unit is mV. The amplitude of the detection signal is constant when the sensor passes a non-defective position and varies when the sensor passes a defective position. Fig. 11(a) and fig. 11(b) are diagrams of detection signals without adding an adjustable capacitor, and fig. 11(c) and fig. 11(d) are diagrams of detection signals with adding an adjustable capacitor, it is obvious that, under the same detection environment, the amplitude variation of the introduced resonance capacitor is larger, the signal noise is smaller, and the detection performance is better.

The above detailed description is for the purpose of describing the invention in detail, and it should not be construed that the detailed description is limited to the description, and it should be understood that various simple deductions and substitutions can be made by those skilled in the art without departing from the spirit of the invention.

Claims

1. A differential eddy current resonance detection sensor, characterized by: the device comprises an exciting coil and a receiving coil which are arranged in a coupling mode, wherein the exciting coil and the receiving coil are formed by winding copper wires, and the receiving coil is connected with a first resonant capacitor in parallel.

2. The differential eddy current resonance detection sensor of claim 1, wherein: the receiving coil comprises a plurality of layers of receiving sub-coils connected in series.

3. The differential eddy current resonance detection sensor of claim 2, wherein: the receiver sub-coil is a PCB rectangular coil.

4. The differential eddy current resonance detection sensor of claim 1, wherein: and the excitation coil is connected with a second resonance capacitor in parallel.

5. The differential eddy current resonance test sensor of claim 1, wherein: the exciting coil is a differential coil.

6. The differential eddy current resonance test sensor of claim 1, wherein: the exciting coil is a PCB differential coil.

7. The differential eddy current resonance test sensor of claim 1, wherein: the exciting coil is a PCB rectangular differential coil.

8. The differential eddy current resonance detection sensor of claim 4, wherein: the first resonance capacitor and/or the second resonance capacitor are/is an adjustable capacitor.

9. The differential eddy current resonance detection sensor of claim 1, wherein: the exciting coil and the receiving coil are coaxially coupled.

10. A differential eddy current resonance detection system, characterized by: the system comprises the detection sensor as claimed in any one of the preceding claims 1 to 9, and further comprises a signal generator and a back-end data processing unit, wherein the signal generator, the detection sensor and the back-end data processing unit are connected in sequence.