CN-121978418-A - Non-continuous conductive layer equivalent conductivity test system, method and medium based on simulation inversion

CN121978418ACN 121978418 ACN121978418 ACN 121978418ACN-121978418-A

Abstract

The application relates to the technical field of equivalent conductivity testing and discloses a system, a method and a medium for testing equivalent conductivity of a discontinuous conductive layer based on simulation inversion, wherein the system comprises a testing module, a testing module and a testing module, wherein the testing module is used for testing a first testing sample corresponding to a magnetic conductive layer of a magnetic shielding device to be tested, obtaining each conductivity, obtaining initial magnetic permeability of a second testing sample under different magnetic field frequencies, and obtaining actual magnetic field intensity of the magnetic shielding device to be tested in a magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities; the processing module is used for determining the intrinsic conductivity, the first relation curve and the second relation curve based on the conductivities collected from the testing module, the initial magnetic permeability under different magnetic field frequencies, the actual magnetic field strength in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field strengths, and performing inversion optimization by utilizing a preset simulation model to obtain the target equivalent conductivity of the discontinuous conductive layer of the tested magnetic shielding device.

Inventors

Shen Zhangtao
MA JIANHAO
JIANG QIAN
CHEN DAIYONG
LU JIANG
YE JING
SHEN KAI

Assignees

杭州极弱磁场国家重大科技基础设施研究院

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. The system for testing the equivalent conductivity of the discontinuous conductive layer based on simulation inversion is characterized by comprising the following components: the test module is used for testing a first test sample corresponding to the magnetically conductive layer of the magnetic shielding device to be tested, obtaining each conductivity of the first test sample, obtaining the initial permeability of a second test sample under different magnetic field frequencies, and obtaining the actual magnetic field strength of the magnetic shielding device to be tested in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field strengths; the processing module is in communication connection with the testing module, and is used for collecting each conductivity of the testing module, initial magnetic conductivity under different magnetic field frequencies, actual magnetic field intensity in a magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities, determining the intrinsic conductivity of a magnetically conductive layer in the passive magnetic shielding device based on each conductivity, determining a first relation curve of the magnetic conductivity and the magnetic field frequency based on the initial magnetic conductivity under the different magnetic field frequencies, determining a second relation curve of the magnetic shielding coefficient and the magnetic field frequency based on the actual magnetic field intensity in the magnetic shielding space under the different magnetic field frequencies and the different excitation magnetic field intensities, and performing inversion optimization by utilizing a preset simulation model to obtain the target equivalent conductivity of the discontinuous conductive layer of the tested magnetic shielding device.
2. The system of claim 1, wherein the test module comprises a metal four probe tester; The output end of the metal four-probe tester is in communication connection with the input end of the processing module; the metal four-probe tester is used for testing the test sample for a plurality of times to obtain a plurality of conductivities, and sending each conductivity to the processing module; the processing module is used for carrying out average value calculation based on each conductivity to obtain the intrinsic conductivity of the test sample.
3. The system of claim 1, wherein the test module comprises an AC/DC soft magnetic tester; the output end of the alternating-current/direct-current soft magnetic tester is in communication connection with the input end of the processing module; The primary current clamp of the AC/DC soft magnetic tester is electrically connected with the primary winding of the test sample, and the secondary current clamp of the AC/DC soft magnetic tester is electrically connected with the secondary winding of the test sample; the alternating current-direct current soft magnetic tester is used for acquiring initial magnetic permeability of the test sample under different frequencies and sending the initial magnetic permeability under different magnetic field frequencies to the processing module.
4. The system of claim 1, wherein the test module comprises a signal generator, a current source, a pair of coils having the same number of turns, and a fluxgate magnetometer; The coil pairs are coaxially and parallelly arranged at two sides of the tested magnetic shielding device; the output end of the signal generator is electrically connected with the input end of the current source and is used for sending sine wave current signals with different frequencies to the current source; The input end of the current source is electrically connected with the output end of the signal generator, the output end of the current source is connected with the coil pair and used for adjusting the received sinusoidal current signals and sending the adjusted sinusoidal current signals to each coil in the coil pair so that each coil emits magnetic fields with different magnetic field frequencies and different magnetic field strengths to the tested magnetic shielding device; The fluxgate magnetometer is used for detecting the actual magnetic field intensity in the magnetic shielding space of the tested magnetic shielding device and sending the actual magnetic field intensity in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities to the processing module.
5. The system of claim 3, wherein the processing module is configured to obtain the first relationship based on a polynomial fit of initial permeability at different magnetic field frequencies.
6. The system of claim 4, wherein the processing module is to: Determining magnetic shielding coefficients based on the excitation magnetic field intensity and the actual magnetic field intensity at each magnetic field frequency to obtain the magnetic shielding coefficients corresponding to the magnetic field frequencies; And performing polynomial fitting based on each magnetic field frequency and the corresponding magnetic shielding coefficient to obtain the second relation curve.
7. The method for testing the equivalent conductivity of the discontinuous conductive layer based on simulation inversion is characterized by comprising the following steps of: testing a first test sample corresponding to the magnetically conductive layer of the magnetic shielding device to be tested, obtaining each conductivity of the first test sample, and determining the intrinsic conductivity of the magnetically conductive layer in the passive magnetic shielding device based on each conductivity; Acquiring initial magnetic permeability of a second test sample under different magnetic field frequencies, and determining a first relation curve of the magnetic permeability and the magnetic field frequency based on the initial magnetic permeability under the different magnetic field frequencies; Acquiring actual magnetic field intensity of a passive magnetic shielding device in a magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities, and determining a second relation curve of magnetic shielding coefficients and magnetic field frequencies based on the actual magnetic field intensity in the magnetic shielding space under the different magnetic field frequencies and the different excitation magnetic field intensities; And performing inversion optimization by utilizing a predetermined simulation model based on the intrinsic conductivity, the first relation curve and the second relation curve to obtain the target equivalent conductivity of the discontinuous conductive layer of the tested magnetic shielding device.
8. The method of claim 7, wherein the performing inversion optimization using a predetermined simulation model based on the intrinsic conductivity, the first relationship, and the second relationship to obtain the target equivalent conductivity of the discontinuous conductive layer of the magnetic shielding device under test specifically comprises: taking the intrinsic conductivity as an initial equivalent conductivity; inputting the initial equivalent conductivity and the initial magnetic permeability corresponding to each magnetic field frequency into the simulation model to obtain the simulation magnetic field intensity corresponding to each magnetic field frequency; calculating an initial deviation value by using an objective function based on the simulated magnetic field intensity corresponding to each magnetic field frequency and the corresponding actual magnetic field intensity, wherein each actual magnetic field intensity is determined based on the second relation curve; And determining whether a preset optimization stopping condition is met or not based on the initial deviation value and a preset deviation threshold value, updating the initial equivalent conductivity and obtaining the current equivalent conductivity when the preset optimization stopping condition is not met, and taking the current equivalent conductivity as a target equivalent conductivity when the current deviation value calculated based on the current equivalent conductivity meets the preset optimization stopping condition.
9. The method of claim 7, wherein said determining the intrinsic conductivity of the magnetically permeable layer in the passive magnetic shielding device based on each of said conductivities comprises performing a mean calculation based on each of said conductivities to obtain the intrinsic conductivity of the test sample; the determining the first relation curve of the magnetic permeability and the magnetic field frequency based on the initial magnetic permeability under the different magnetic field frequencies specifically comprises the following steps: and performing polynomial fitting based on initial magnetic permeability under different magnetic field frequencies to obtain the first relation curve.
10. A storage medium storing a computer program which, when executed by a processor, implements the steps of the simulation inversion based method for testing the equivalent conductivity of a discontinuous conductive layer according to any one of the preceding claims 7-9.

Description

Non-continuous conductive layer equivalent conductivity test system, method and medium based on simulation inversion Technical Field The invention relates to the technical field of equivalent conductivity testing, in particular to a discontinuous conductive layer equivalent conductivity testing system, method and medium based on simulation inversion. Background The basic principle of magnetic shielding derives from the "flux splitting" effect of high magnetic permeable materials on static/low frequency magnetic fields, and the "eddy current shielding" effect of high conductive materials on high frequency magnetic fields. In order to simultaneously inhibit the broadband interference of the geomagnetic field and 0.01Hz-1kHz, the passive magnetic shielding device generally combines and uses a magnetically conductive layer and a high conductive layer, so that the inside of a shielding space reaches a weak magnetic environment with the nT-pT magnitude. Obviously, the permeability of the magnetically permeable layer and the conductivity of the highly conductive layer are the core parameters that determine the shielding effectiveness. In a small magnetic shielding box/cylinder of laboratory level, the high conductive layer is small in size, small in thickness and thin, can be formed at one time through processes such as bending, rolling and the like, has continuous conductive paths, has macroscopic conductivity approximately equal to the intrinsic value of a material, and can be rapidly and accurately measured by a four-probe method. However, when the shielding cavity is enlarged to the level of meters or even the level of tens of meters, such as a magnetic shielding cavity of a brain magnetic graphics (MEG) laboratory, a zero magnetic medical cabin, a quantum metering cabin and the like, the high conductive layer can only adopt a modularized assembly mode of 'small plates-lap joints-rivet welding/bolts' under the constraint of the width and the transportation limit of a rolling mill. The factors such as overlap joint gap, bolt hole, surface oxide film and contact pressure are uneven, make the current channel appear showing shrink and roundabout, lead to the equivalent conductivity and the intrinsic conductivity difference of monoblock shielding layer great, and show obvious anisotropy. At present, only the equivalent conductivity test of a continuous foil or a sprayed film is focused in the prior art, however, no corresponding measurement scheme exists at present aiming at the equivalent conductivity of a discontinuous high conductive layer of a large-scale magnetic shielding device, and the equivalent conductivity test becomes a key blind area for limiting the design and simulation precision of the high shielding performance. Therefore, a discontinuous conductive layer equivalent conductivity test system based on simulation inversion is needed to solve the problem that the equivalent conductivity of a discontinuous conductive layer in a magnetic shielding device cannot be tested rapidly and accurately in the prior art. Disclosure of Invention In view of the above, the invention provides a system, a method and a medium for testing the equivalent conductivity of a discontinuous conductive layer based on simulation inversion, which mainly aims to solve the problem that the equivalent conductivity of the discontinuous conductive layer in a magnetic shielding device cannot be tested rapidly and accurately at present. In order to solve the above problems, the present application provides a discontinuous conductive layer equivalent conductivity test system based on simulation inversion, comprising: the test module is used for testing a first test sample corresponding to the magnetically conductive layer of the magnetic shielding device to be tested, obtaining each conductivity of the first test sample, obtaining the initial permeability of a second test sample under different magnetic field frequencies, and obtaining the actual magnetic field strength of the magnetic shielding device to be tested in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field strengths; The processing module is in communication connection with the testing module, and is used for collecting each conductivity transmitted by the testing module, the initial permeability under different magnetic field frequencies, and the actual magnetic field intensity in the magnetic shielding space under different magnetic field frequencies and different excitation magnetic field intensities, determining the intrinsic conductivity of the magnetically conductive layer in the passive magnetic shielding device based on each conductivity, determining a first relation curve of the permeability and the magnetic field frequency based on the initial permeability under different magnetic field frequencies, determining a second relation curve of the magnetic shielding coefficient and the magnetic field frequency b