High-frequency magnetic field excited tiny metal particle detection system and detection method

Abstract

The invention discloses a high-frequency magnetic field excited tiny metal particle detection system and detection method. The system comprises a high-frequency signal excitation module, a high-frequency signal amplification circuit module, a nested metal particle detection device, a signal processing module, an upper computer, a power supply module and the like, the high-frequency signal excitation module is used for generating a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude; the high-frequency signal amplification module is used for amplifying the high-frequency sinusoidal signal and converting the high-frequency sinusoidal signal into a current signal to drive an excitation coil; an excitation coil in the nested metal particle detection device is used for generating an alternating magnetic field, and an induction coil is used for inducing magnetic field change caused by metal particles; the signal processing module is responsible for processing and extracting particle signal feature information and displaying the particle signal feature information through the upper computer. The nested metal particle detection device is seamlessly connected in the pipeline, the pipeline cannot be damaged, liquid cannot be polluted, and detection of smaller metal particles can be met by effectively combining high-frequency magnetic field excitation and the nested detection device.

Description

Technical Field

[0001] The present invention relates to the technical field of particle detection in oil pipelines of mechanical equipment, and in particular to a tiny metal particle detection system and a detection method excited by a high-frequency magnetic field. Background Art

[0002] With the continuous progress of industrial manufacturing, the quality and performance requirements of mechanical equipment have become increasingly stringent. As a common manifestation of mechanical equipment wear, tiny particles may be generated due to friction, abrasion, corrosion and other factors, and most of the particles generated will enter the oil pipeline. The formation of tiny particles may not only lead to the performance degradation of parts, but also cause system failure. Therefore, real-time monitoring and accurate identification of tiny metal particles in oil pipelines have become crucial. Traditional metal particle detection methods, such as optical microscope detection, have defects such as complex operation, reliance on manual labor, and inability to monitor in real time. In order to make up for these shortcomings, magnetic field excitation detection technology has emerged. The magnetic field excitation detection system can capture the presence of tiny metal particles in real time without interfering with the normal production process by sensitively detecting the magnetic field changes caused by tiny metal particles. However, the existing magnetic field excitation detection technology still has some challenges when facing tiny metal particles, especially for tiny particles with higher frequency and smaller size, which have higher requirements for sensitivity and real-time performance. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a tiny metal particle detection system and detection method excited by a high-frequency magnetic field to solve the problems raised in the above-mentioned background technology.

[0004] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0005] A micro-metal particle detection system excited by a high-frequency magnetic field comprises: a high-frequency signal excitation module, a high-frequency signal amplification circuit module, a nested metal particle detection device, a signal processing module, a host computer and a power supply module;

[0006] The high-frequency signal excitation module includes a control unit, a signal generating circuit, a crystal oscillator and a key module. The control unit provides a signal to the signal generating circuit through the crystal oscillator. The signal generating circuit uses direct digital frequency synthesis DDS to excite the phase-locked loop PLL to accurately generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude. After being processed by the high-frequency signal amplification circuit module, it is used as an excitation signal for the nested metal particle detection device. The key module is used to adjust the frequency of the high-frequency signal and control the frequency addition and subtraction. The control unit is controlled by FPGA and connected to other modules using DuPont lines. The control unit controls the entire system.

[0007] The high-frequency signal amplification circuit module includes a low-noise amplification circuit, a voltage follower circuit, a high-frequency voltage-to-current module and a power amplification circuit. The low-noise amplification circuit and the voltage follower circuit use a low-noise operational amplifier. The high-frequency voltage-to-current module converts the high-frequency voltage signal generated by the excitation module into a current signal to drive the excitation coil. The power amplification circuit is used to provide a stable high-power output. The output end of the power amplification circuit module is connected to the excitation coil of the nested metal particle detection device.

[0008] The nested metal particle detection device comprises an excitation coil A, an excitation coil B, an induction coil, an inner frame and an outer frame, wherein the excitation coil A is wound around the left half of the inner frame, the excitation coil B is wound around the right half of the inner frame, an outer frame is installed around the inner frame, and an induction coil is wound in the installation groove of the outer frame; the excitation coil A and the excitation coil B receive a high-frequency sinusoidal signal amplified by a high-frequency signal amplification circuit module, the excitation coil A and the excitation coil B generate an alternating magnetic field, the induction coil generates an induction signal, and the output end of the induction coil is connected to the input end of the signal processing module;

[0009] The signal processing module is electrically connected to the low-noise differential amplifier circuit, the modulator circuit, the low-pass filter circuit, the demodulator circuit and the suffix amplifier circuit in sequence to extract the metal particle signal from the sensing signal. The output end of the suffix amplifier circuit is connected to the input end of the high-speed A / D converter to identify the specific form of the tiny metal particles and transmit it to the host computer for real-time display;

[0010] The power supply module provides power for the high-frequency signal excitation module, the high-frequency signal amplification circuit module, and the signal processing module.

[0011] Preferably, the number of turns, length and radius of the excitation coil A and the excitation coil B are consistent, the excitation coil A and the excitation coil B are connected in series, the excitation coil A and the excitation coil B generate alternating magnetic fields of equal magnitude and opposite directions, a zero magnetic field is formed at the intersection of the excitation coil A and the excitation coil B, and the number of turns and length of the induction coil are the sum of the excitation coil A and the excitation coil B.

[0012] Preferably, the inner frame and the outer frame are cylindrical, and a cylindrical pipe passes through the central axis of the inner frame.

[0013] Preferably, when metal particles enter the nested metal particle detection device, the induced electromotive force formula output by the induction coil is:

[0014]

[0015] In the formula, x is the horizontal coordinate of the metal particle; R is the diameter of the pipeline, R1 is the inner diameter of the excitation coil A and the excitation coil B; R2 is the outer diameter of the excitation coil A and the excitation coil B; d is the length of the excitation coil A and the excitation coil B; L is the distance between the excitation coil A and the excitation coil B; μ0 is the vacuum magnetic permeability; μ1 is the relative magnetic permeability of the particle; I is the current value of the excitation signal; n is the number of turns of the excitation coil; n1 is the number of turns of the induction coil; f is the frequency of the sinusoidal excitation signal; v is the movement speed of the particle; r is the radius of the metal particle; v0 is the volume of the particle, and h is the length of the particle entering the nested metal particle detection device.

[0016] A detection method for a micro-metal particle detection system excited by a high-frequency magnetic field, characterized in that it comprises the following steps:

[0017] S1. By setting the relevant parameters of the high-frequency signal excitation module, the direct digital frequency synthesis DDS excitation phase-locked loop PLL is used to generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude;

[0018] S2. The high-frequency signal amplification module amplifies the high-frequency sinusoidal signal generated in step S1 and converts the voltage into flow to drive the excitation coil A and the excitation coil B of the nested metal particle detection device to generate an alternating magnetic field of equal magnitude and opposite direction;

[0019] S3. When metal particles in the oil pipeline pass through the nested metal particle detection device, the tiny metal particles will affect the alternating magnetic field generated by the excitation coil, and then the induction coil will collect an induction signal different from that when there are no metal particles;

[0020] S4. The signal processing module extracts the metal particle signal from the sensing signal, converts the metal particle analog signal into a digital signal, and uses the DSP digital signal processing unit integrated in the FPGA to filter the particle digital signal and use the wavelet transform algorithm to extract features, and uses the deep learning algorithm to classify and identify the metal particle signal;

[0021] S6. Determine whether metal particles have passed through the detection device based on whether the induced magnetic field has changed; determine whether the metal particles are ferromagnetic particles based on whether the phase of the particle signal is positive first and then negative; set the induced signal amplitude threshold, and determine whether to accumulate the number of particles based on whether the induced signal amplitude V exceeds the threshold; calculate the speed of the particles based on the difference in the number of sampling points corresponding to the peak-to-peak value of the particle signal and the length of the detection device;

[0022] S7. The relevant data and analysis results are displayed in real time on the host computer through the corresponding communication protocol, realizing efficient detection and accurate diagnosis of tiny metal particles.

[0023] The beneficial effects of the present invention are:

[0024] The present invention adopts the scheme of direct digital frequency synthesis technology DDS excitation phase-locked loop PLL to accurately generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude as the excitation signal of the nested metal particle detection device. Compared with the existing traditional technology, the signal frequency is higher, which can effectively meet the detection needs of smaller particles and improve the sensitivity of small-sized particle detection. The nested metal particle detection device adopted by the present invention, in which two excitation coils excite an alternating magnetic field after passing a high-frequency excitation signal, can obtain more particle characteristics and is more sensitive to the magnetic field changes caused by tiny particles compared with the traditional three-coil detection sensor. The corresponding magnetic shielding device can be nested on the outside of the detection device skeleton used in the present invention, which can effectively shield the influence of the external magnetic field on the detection results, help to improve the system's recognition accuracy of tiny metal particles, and can also be connected to the oil pipeline to directly measure metal particles to ensure the real-time detection of particle information. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 1 It is an overall schematic diagram of the system of the present invention;

[0027] Figure 2 It is a working principle diagram of the DDS excitation phase-locked loop PLL in the present invention;

[0028] Figure 3 is a cross-sectional view of the nested metal particle detection device of the present invention;

[0029] Figure 4 A magnetic field distribution diagram of particles entering the nested metal particle detection device in the present invention;

[0030] Figure 5 Flow chart of metal particle characteristics and identification in the present invention. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0033] Please refer to Figure 1-5 , a micro-metal particle detection system excited by a high-frequency magnetic field, comprising: a high-frequency signal excitation module 1, a high-frequency signal amplification circuit module 2, a nested metal particle detection device 3, a signal processing module 4, a host computer 5 and a power supply module 6;

[0034] The high-frequency signal excitation module 1 includes a control unit 11, a signal generating circuit 12, a crystal oscillator 13 and a key module 14. The control unit 11 provides a signal to the signal generating circuit 12 through the crystal oscillator 13. The signal generating circuit 12 adopts a direct digital frequency synthesis DDS excitation phase-locked loop PLL solution to output a sine wave signal in the range of 1kHz-1GHz. The DDS initially generates low-frequency to high-frequency signals with its advantages of high performance, high flexibility and low power consumption, while the PLL generates high-precision signals in a very wide frequency range with low jitter and phase noise. The output of the DDS is used as a reference source of the PLL. The PLL amplifies the low-frequency signal generated by the DDS to the high-frequency signal range. After the two are cascaded, the output bandwidth of the DDS is increased by the frequency multiplication of the phase-locked loop, and the high-frequency sine signal with stable and adjustable frequency, phase and amplitude is accurately generated. After being processed by the high-frequency signal amplification circuit module 2, it is used as the excitation signal of the nested metal particle detection device 3. The key module 14 is used to adjust the frequency of the high-frequency signal and control the frequency addition and subtraction. The control unit 11 is controlled by FPGA and connected to other modules by DuPont lines. The control unit 11 controls the entire system;

[0035] The DDS includes a k-bit phase accumulator, a waveform memory, a D / A converter and a low-pass filter; the PLL includes a frequency detector, a charge pump, a voltage-controlled oscillator and a frequency divider. The frequency output by the signal generating circuit 12 is:

[0036]

[0037] Where: F out Represents the output frequency; F clk Represents the input clock frequency; FTW represents the frequency control word in DDS; MF represents the output frequency division factor of the phase-locked loop PLL multiplier.

[0038] The key module 14 is used to adjust the frequency of the high-frequency signal, wherein the key 0 is used to control the frequency increase, the key 1 is used to control the frequency decrease, and the key REST is used to reset the sine output waveform. The control unit 11 is controlled by FPGA and connected to other modules using Dupont lines. The control unit 11 fully controls the entire system.

[0039] The input end of the high-frequency signal amplification circuit module 2 is connected to the output end of the high-frequency signal excitation module 1, and the high-frequency signal synthesized by the high-frequency signal excitation module 1 is subjected to low-noise amplification, voltage following, voltage-to-current conversion, and power amplification. In order to achieve impedance matching between the signal generating circuit 12 and the high-frequency signal excitation module 1, avoid signal distortion, ensure the signal strength of the high-frequency signal, and protect the high-frequency signal excitation module 1 from the influence of load changes, the high-frequency signal amplification circuit module 2 includes a low-noise amplification circuit 21, a voltage following circuit 22, a high-frequency voltage-to-current conversion module 23, and a power amplification circuit 24. The low-noise amplification circuit 21 and the voltage following circuit 22 use a low-noise operational amplifier to ensure the signal strength of the high-frequency signal, improve the signal-to-noise ratio, and protect the front-stage high-frequency signal excitation module 1 from the influence of load changes; the high-frequency voltage-to-current conversion module 23 converts the high-frequency voltage signal generated by the excitation module into a current signal to drive the excitation coil, and a high-performance operational amplifier is selected to design the voltage-to-current module; the power amplifier circuit 24 is used to provide a stable high-power output to meet the requirements of the detection system, and the output end of the power amplifier circuit 24 module is connected to the excitation coil of the nested metal particle detection device 3;

[0040] The nested metal particle detection device 3 includes an excitation coil A 31, an excitation coil B 32, an induction coil 33, an inner frame 34 and an outer frame 35. The excitation coil A 31 is wound around the left half of the inner frame 34, the excitation coil B 32 is wound around the right half of the inner frame 34, the outer frame 35 is installed around the inner frame 34, and the induction coil 33 is wound in the installation groove of the outer frame 35; the excitation coil A 31 and the excitation coil B 32 receive the high-frequency sinusoidal signal amplified by the high-frequency signal amplification circuit module 2, the excitation coil A 31 and the excitation coil B 32 generate an alternating magnetic field, and the induction coil 33 generates an induction signal. When there are metal particles, the tiny metal particles will affect the alternating magnetic field generated by the excitation coil, and then generate an induction signal different from that when there are no particles at the induction coil 33, and the output end of the induction coil 33 is connected to the input end of the signal processing module 4;

[0041] The signal processing module 4 is electrically connected to the low-noise differential amplifier circuit 41, the modulator circuit 42, the low-pass filter circuit 43, the demodulator circuit 44 and the suffix amplifier circuit 45 in sequence to extract the metal particle signal from the sensing signal. The output end of the suffix amplifier circuit 45 is connected to the input end of the high-speed A / D converter 46 to convert the metal particle analog signal into a digital signal. Then, the FPGA integrated DSP digital signal processing 47 is used to filter the particle signal and extract features using a wavelet transform algorithm. According to the particle features and data characteristics, a deep learning algorithm is used to classify and identify the metal particle signal, and the specific form of the tiny metal particles is determined and transmitted to the host computer 5 for real-time display;

[0042] The power supply module 6 provides power to the high-frequency signal excitation module 1 , the high-frequency signal amplification circuit module 2 , and the signal processing module 4 .

[0043] The number of turns, length and radius of the excitation coil A 31 and the excitation coil B 32 are consistent. The excitation coil A 31 and the excitation coil B 32 are connected in series. The excitation coil A 31 and the excitation coil B 32 generate alternating magnetic fields of equal magnitude and opposite directions. A zero magnetic field is formed at the intersection of the excitation coil A 31 and the excitation coil B 32. The number of turns and length of the induction coil 33 are the sum of the excitation coil A 31 and the excitation coil B 32. The inner skeleton 34 and the outer skeleton 35 are cylindrical. The central axis of the inner skeleton 34 is penetrated by a cylindrical pipe. The size can be designed according to the size of the actual oil pipeline. The device is connected to the oil pipeline to realize in-situ and real-time metal particle detection. When there are metal particles, the tiny metal particles will affect the alternating magnetic field generated by the excitation coil, and then generate an induction signal at the induction coil 33 that is different from that when there are no particles. The magnetic induction intensity formula of the excitation coil A 31 and the excitation coil B 32 for the metal particle P will be different due to the different positions of the coordinate system. For example, Figure 2 , a coordinate system is established with the center of the detection device as the origin. According to the Biot-Savart law, when metal particles enter the excitation coil A31, the magnetic field excited by the multilayer excitation coil A31 at any point P is:

[0044]

[0045] When the metal particles enter the excitation coil B 32, the magnetic induction intensity of the excitation coil B 32 at point P is:

[0046]

[0047] When metal particles enter the nested metal particle detection device 3, the magnetic permeability of the space medium increases, and the magnetic resistance of the entering part decreases. Since the metal particles with relatively large magnetic permeability are magnetized, they replace the air medium in the area without particles, resulting in an increase in the local inductance of the coil in the covered area, causing an increase in the magnetic induction intensity B in the space surrounded by the metal particle volume, and ultimately increasing the coil magnetic flux. According to the relationship between the induced electromotive force and the mutual inductance E = 2πfΔM, combined with the mutual inductance coefficient, it is defined as Change in magnetic flux of the induction coil 33 axis The magnetic induction intensity formula at any point P of the multilayer coil, the equivalent change of current ΔI=I-I1, and the inductance theorem And the value-added formula of inductance When h≈2r, the electromotive force output by the induction coil 33 when the particle passes through the detection device is obtained:

[0048]

[0049] In the formula, x is the horizontal coordinate of the metal particle; R is the diameter of the pipeline, R1 is the inner diameter of the excitation coil A 31 and the excitation coil B 32; R2 is the outer diameter of the excitation coil A 31 and the excitation coil B 32; d is the length of the excitation coil A 31 and the excitation coil B 32; L is the distance between the excitation coil A 31 and the excitation coil B 32; μ0 is the vacuum magnetic permeability; μ1 is the relative magnetic permeability of the particle; I is the current value of the excitation signal; n is the number of turns of the excitation coil; n1 is the number of turns of the induction coil 33; f is the frequency of the sinusoidal excitation signal; v is the movement speed of the particle; r is the radius of the metal particle; v0 is the volume of the particle, and h is the length of the particle entering the nested metal particle detection device 3.

[0050] The radius r of the metal particle is in micrometers, and the frequency unit of the sinusoidal excitation signal is in megahertz. When other parameters remain unchanged, the numerator and denominator of the metal particle in the output induced electromotive force formula are of the same order of magnitude. The greater the frequency of the sinusoidal excitation signal, the greater the output induced electromotive force and the smaller the size of the detected metal particles.

[0051] Metal particles will generate a low-frequency induction signal when passing through the nested particle detection device. After low-noise differential amplification to suppress common-mode noise, the low-frequency signal is modulated onto a high-frequency carrier through a modulator circuit 42. The irrelevant signal components are filtered out and the signal quality is improved through a low-pass filter 43. The original signal is then restored from the high-frequency modulated signal through a demodulation circuit 44. The demodulated signal still contains residual noise, so it is filtered out again through a low-pass filter circuit to remove the residual high-frequency noise to ensure the stability and accuracy of the signal. Finally, it is amplified through a suffix amplifier circuit 45 to output a high-quality, low-noise particle signal.

[0052] The output end of the suffix amplifier circuit 45 is connected to the input end of the high-speed A / D converter 46. The high-speed A / D converter 46 samples the analog signal of the metal particles at a certain sampling frequency, converts the continuous particle signal into a series of discrete sample values, and each sampling value is mapped to the closest digital value, thereby realizing the conversion of the analog signal of the metal particles to the digital signal.

[0053] Figure 5 As shown in FIG. 4 , it is a flowchart of metal particle characteristics and identification. The DSP digital signal processing 47 integrated in FPGA is used to filter the digital signal of the particle and use the wavelet transform algorithm to extract the characteristics. The metal particle signal is classified and identified using the deep learning algorithm according to the particle characteristics and data characteristics. Specifically, whether the induced magnetic field changes is judged to determine whether there are metal particles entering the detection device; whether the metal particles are ferromagnetic particles is judged according to the phase of the particle signal; and the induced signal amplitude threshold V is set. max , according to whether the induction signal amplitude V exceeds the threshold V max To determine whether to accumulate the number of particles; calculate the particle speed based on the difference in the number of sampling points corresponding to the peak-to-peak value of the particle signal and the length of the detection device; and then identify the specific form of the tiny metal particles. Finally, these data and analysis results are displayed in real time on the host computer through the corresponding communication protocol, thereby achieving efficient detection and accurate diagnosis of tiny metal particles.

[0054] A detection method of a tiny metal particle detection system excited by a high-frequency magnetic field comprises the following steps:

[0055] S1. By setting the relevant parameters of the high-frequency signal excitation module 1, a direct digital frequency synthesis DDS excitation phase-locked loop PLL is used to generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude;

[0056] S2. The high-frequency signal amplification module 14 amplifies the high-frequency sinusoidal signal generated in step S1 and converts the voltage into flow to drive the excitation coil A 31 and the excitation coil B 32 of the nested metal particle detection device 3 to generate an alternating magnetic field of equal magnitude and opposite direction;

[0057] S3. When metal particles in the oil pipeline pass through the nested metal particle detection device 3, the tiny metal particles will affect the alternating magnetic field generated by the excitation coil, and then the induction coil 33 collects an induction signal different from that when there are no metal particles;

[0058] S4. The signal processing module 4 extracts the metal particle signal from the sensing signal, converts the metal particle analog signal into a digital signal, and uses the DSP digital signal processing unit integrated in the FPGA to filter the particle digital signal and use the wavelet transform algorithm to extract features, and uses the deep learning algorithm to classify and identify the metal particle signal;

[0059] S6. Determine whether metal particles have passed through the detection device based on whether the induced magnetic field has changed; determine whether the metal particles are ferromagnetic particles based on whether the phase of the particle signal is positive first and then negative; set the induced signal amplitude threshold, and determine whether to accumulate the number of particles based on whether the induced signal amplitude V exceeds the threshold; calculate the speed of the particles based on the difference in the number of sampling points corresponding to the peak-to-peak value of the particle signal and the length of the detection device;

[0060] S7. The relevant data and analysis results are displayed in real time on the host computer 5 through the corresponding communication protocol, so as to achieve efficient detection and accurate diagnosis of tiny metal particles.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A micro-metal particle detection system excited by a high-frequency magnetic field, characterized in that: include: High-frequency signal excitation module, high-frequency signal amplification circuit module, nested metal particle detection device, signal processing module, host computer and power supply module; The high-frequency signal excitation module includes a control unit, a signal generating circuit, a crystal oscillator and a key module. The control unit provides a signal to the signal generating circuit through the crystal oscillator. The signal generating circuit uses direct digital frequency synthesis DDS to excite the phase-locked loop PLL to accurately generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude. After being processed by the high-frequency signal amplification circuit module, it is used as an excitation signal for the nested metal particle detection device. The key module is used to adjust the frequency of the high-frequency signal and control the frequency addition and subtraction. The control unit is controlled by FPGA and connected to other modules using DuPont lines. The control unit controls the entire system. The high-frequency signal amplification circuit module includes a low-noise amplification circuit, a voltage follower circuit, a high-frequency voltage-to-current module and a power amplification circuit. The low-noise amplification circuit and the voltage follower circuit use a low-noise operational amplifier. The high-frequency voltage-to-current module converts the high-frequency voltage signal generated by the excitation module into a current signal to drive the excitation coil. The power amplification circuit is used to provide a stable high-power output. The output end of the power amplification circuit module is connected to the excitation coil of the nested metal particle detection device. The nested metal particle detection device comprises an excitation coil A, an excitation coil B, an induction coil, an inner frame and an outer frame, wherein the excitation coil A is wound around the left half of the inner frame, the excitation coil B is wound around the right half of the inner frame, an outer frame is installed around the inner frame, and an induction coil is wound in the installation groove of the outer frame; the excitation coil A and the excitation coil B receive a high-frequency sinusoidal signal amplified by a high-frequency signal amplification circuit module, the excitation coil A and the excitation coil B generate an alternating magnetic field, the induction coil generates an induction signal, and the output end of the induction coil is connected to the input end of the signal processing module; The signal processing module is electrically connected to the low-noise differential amplifier circuit, the modulator circuit, the low-pass filter circuit, the demodulator circuit and the suffix amplifier circuit in sequence to extract the metal particle signal from the sensing signal. The output end of the suffix amplifier circuit is connected to the input end of the high-speed A / D converter to identify the specific form of the tiny metal particles and transmit it to the host computer for real-time display; The power supply module provides power for the high-frequency signal excitation module, the high-frequency signal amplification circuit module, and the signal processing module.

2. A high-frequency magnetic field excited tiny metal particle detection system according to claim 1, characterized in that: The number of turns, length and radius of the excitation coil A and the excitation coil B are consistent. The excitation coil A and the excitation coil B are connected in series. The excitation coil A and the excitation coil B generate alternating magnetic fields of equal magnitude and opposite directions. A zero magnetic field is formed at the intersection of the excitation coil A and the excitation coil B. The number of turns and length of the induction coil are the sum of the excitation coil A and the excitation coil B.

3. The high-frequency magnetic field excited tiny metal particle detection system according to claim 2, characterized in that: The inner frame and the outer frame are cylindrical, and a cylindrical pipe runs through the central axis of the inner frame.

4. The high-frequency magnetic field excited tiny metal particle detection system according to claim 3, characterized in that: When metal particles enter the nested metal particle detection device, the induced electromotive force formula output by the induction coil is: In the formula, x is the horizontal coordinate of the metal particle; R is the diameter of the pipeline, R1 is the inner diameter of the excitation coil A and the excitation coil B; R2 is the outer diameter of the excitation coil A and the excitation coil B; d is the length of the excitation coil A and the excitation coil B; L is the distance between the excitation coil A and the excitation coil B; μ0 is the vacuum magnetic permeability; μ1 is the relative magnetic permeability of the particle; I is the current value of the excitation signal; n is the number of turns of the excitation coil; n1 is the number of turns of the induction coil; f is the frequency of the sinusoidal excitation signal; v is the movement speed of the particle; r is the radius of the metal particle; v0 is the volume of the particle, and h is the length of the particle entering the nested metal particle detection device.

5. A detection method for a micro-metal particle detection system excited by a high-frequency magnetic field, characterized in that: The following steps are involved: S1. By setting the relevant parameters of the high-frequency signal excitation module, the direct digital frequency synthesis DDS excitation phase-locked loop PLL is used to generate a high-frequency sinusoidal signal with stable and adjustable frequency, phase and amplitude; S2. The high-frequency signal amplification module amplifies the high-frequency sinusoidal signal generated in step S1 and converts the voltage into flow to drive the excitation coil A and the excitation coil B of the nested metal particle detection device to generate an alternating magnetic field of equal magnitude and opposite direction; S3. When metal particles in the oil pipeline pass through the nested metal particle detection device, the tiny metal particles will affect the alternating magnetic field generated by the excitation coil, and then the induction coil will collect an induction signal different from that when there are no metal particles; S4. The signal processing module extracts the metal particle signal from the sensing signal, converts the metal particle analog signal into a digital signal, and uses the DSP digital signal processing unit integrated in the FPGA to filter the particle digital signal and use the wavelet transform algorithm to extract features, and uses the deep learning algorithm to classify and identify the metal particle signal; S6. Determine whether metal particles have passed through the detection device based on whether the induced magnetic field has changed; determine whether the metal particles are ferromagnetic particles based on whether the phase of the particle signal is positive first and then negative; set the induced signal amplitude threshold, and determine whether to accumulate the number of particles based on whether the induced signal amplitude V exceeds the threshold; calculate the speed of the particles based on the difference in the number of sampling points corresponding to the peak-to-peak value of the particle signal and the length of the detection device; S7. The relevant data and analysis results are displayed in real time on the host computer through the corresponding communication protocol, realizing efficient detection and accurate diagnosis of tiny metal particles.

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