CN112578329A - System and method based on alternating magnetic field coil equivalent induction area calibration - Google Patents

System and method based on alternating magnetic field coil equivalent induction area calibration Download PDF

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CN112578329A
CN112578329A CN202011508051.7A CN202011508051A CN112578329A CN 112578329 A CN112578329 A CN 112578329A CN 202011508051 A CN202011508051 A CN 202011508051A CN 112578329 A CN112578329 A CN 112578329A
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coil
standard
probe
detected
solenoid
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陈明
陈大龙
郭笔豪
石同辉
沈飊
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Hefei Institutes of Physical Science of CAS
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Hefei Institutes of Physical Science of CAS
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    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract

The invention discloses a system and a method for calibrating equivalent induction area based on an alternating magnetic field coil, which comprises a current source, a fixed resistor, a long straight solenoid, a coil fixing clamp, a standard coil and a voltage acquisition device, wherein the current source is connected with the fixed resistor; one end output of the current source is connected to a power resistor, and the fixed resistor is connected with the other end of the current source in series to form a loop; the standard coil and the coil to be detected are respectively fixed on the coil fixing clamp; the coil fixing clamp is placed in the long straight solenoid, so that the positions of the standard coil and the coil to be detected are symmetrical relative to the center of the long straight solenoid, the two ends of the standard coil and the two ends of the coil to be detected are connected to the two acquisition ports of the voltage acquisition equipment respectively, and the output voltages of the standard coil and the coil to be detected are acquired simultaneously. The method can quickly measure the equivalent induction area of the coil to be measured, the calibration operation is simple, the calibration precision can reach within one thousandth, and the simultaneous calibration of a plurality of probe coils can be realized.

Description

System and method based on alternating magnetic field coil equivalent induction area calibration
Technical Field
The invention relates to the technical field of electromagnetic measurement, in particular to a system and a method for calibrating equivalent induction area of a high-precision probe coil based on an alternating magnetic field.
Background
The magnetic field probe coil is formed by winding a plurality of circles of conducting wires on a framework made of nonmagnetic materials, all the circles are mutually insulated, the magnetic field intensity of the spatial position where the magnetic field probe coil is located can be measured through electromagnetic induction, and the magnetic field probe coil has the characteristics of high measurement accuracy, stable work at high temperature and the like. The individual difference is inevitably generated in the winding process of the probe coil, so each coil needs to be calibrated after the winding is finished, and the probe coil can be used after the calibration is finished. Coil calibration system commonly used in the existing market all relies on large-scale magnet to produce strong magnetic field, and then marks in strong magnetic field, because large-scale magnet is difficult for obtaining, and need use hall element to measure magnetic field intensity and degree of consistency when using, complex operation is not applicable to and marks a large amount of coils one by one.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a high-efficiency probe coil induction area calibration system and method based on an alternating magnetic field, which can accurately calibrate the induction area of a coil and realize simultaneous calibration of the areas of a plurality of probe coils; the method does not depend on a large magnet and high-precision feedback current, does not need to measure the magnetic field intensity during use, can simply and quickly realize the area calibration of a large number of probes in a laboratory, and has the maximum relative error less than one per thousand.
The technical scheme of the invention is as follows: a system based on alternating magnetic field coil equivalent induction area calibration comprises a current source, a fixed resistor, a long straight solenoid, a coil fixing clamp, a standard coil and a voltage acquisition device; one end output of the current source is connected to a power resistor, and the fixed resistor is connected with the other end of the current source in series to form a loop; the standard coil and the coil to be detected are respectively fixed on the coil fixing clamp; the coil fixing clamp is placed in the long straight solenoid, so that the positions of the standard coil and the coil to be detected are symmetrical relative to the center of the long straight solenoid, the two ends of the standard coil and the two ends of the coil to be detected are connected to the two acquisition ports of the voltage acquisition equipment respectively, and the output voltages of the standard coil and the coil to be detected are acquired simultaneously.
Furthermore, the number of the probe coils to be detected is one or more, and the probe coils can be simultaneously fixed at different positions of the coil fixing clamp for simultaneous measurement; the output voltage of each probe coil is connected to a different voltage acquisition port of a voltage acquisition device.
Furthermore, the fixed resistor is a high-power resistor, the resistor is 5-20 ohms, and the power is 1000-5000 watts.
Furthermore, the current source is a sinusoidal current source with adjustable frequency and amplitude, and the current output with a peak value of more than 3A can be realized when the working frequency is 100-500 Hz.
Furthermore, the length of the long straight solenoid is 500mm-1500mm, the long straight solenoid can be adjusted according to the number of the probe coils to be measured, and more coils can be measured simultaneously by increasing the length and the number of turns of the solenoid.
Furthermore, the coil fixing clamp ensures that the relative positions of the probe coil to be tested, the standard coil and the solenoid are fixed and are symmetrically distributed on two sides of the central section of the solenoid, the coil fixing clamp comprises a coil fixing base, a plurality of coil adjusting supports are arranged on the coil fixing base and are arranged symmetrically left and right along the central line of the solenoid, and a push-pull handle is arranged at the front end of the coil fixing base;
according to another aspect of the present invention, a method for calibrating an equivalent induction area based on an alternating magnetic field coil is further provided, which includes the following steps:
step 1, fixing a probe coil to be detected and a standard coil on a coil fixing clamp;
step 2, adjusting the current of the current source according to the equivalent area of the probe coil to be detected and the standard coil, so that the output voltages of the probe coil to be detected and the standard coil are matched with the acquisition equipment;
step 3, starting a current source to supply power to the solenoid and the resistor series loop;
step 4, collecting through voltageThe equipment collects the voltage epsilon at two ends of the coil of the probe to be testedtest(t) and the voltage ε at both ends of the standard coilstd(t)；
Step 5, respectively carrying out Fourier decomposition on the two collected voltage waveforms to obtain the amplitude values of the single-side amplitude spectrum at the corresponding frequency; calculating the equivalent induction area S of the probe coil to be detected:
Figure BDA0002845493290000021
wherein S isstdIs the equivalent induction area, X, of a standard coiltestAnd XstdThe amplitudes of the coil to be detected and the standard coil output voltage at the corresponding frequency are respectively.
Further, the power source is a sinusoidal alternating current source, so that the current in the solenoid is a sinusoidal alternating current, and the magnetic field in the solenoid is:
B＝Bm sinω0t
wherein, BmIs the maximum value of the magnetic field, ω0Is the angular frequency of the sinusoidal alternating current in the solenoid; from the change in the magnetic field:
Figure BDA0002845493290000022
Figure BDA0002845493290000023
wherein epsilontest(t) is the voltage value at two ends of the coil of the probe to be measured, phitestIs the magnetic flux of the coil to be measured, StestThe equivalent area of the coil to be measured; epsilonstd(t) is the voltage across the coil of the standard probe, phistdIs the magnetic flux of a standard coil, SstdEquivalent area for standard coil:
Figure BDA0002845493290000031
Figure BDA0002845493290000032
wherein
Figure BDA0002845493290000033
And
Figure BDA0002845493290000034
is epsilontest(t) and εstd(t) fourier transform, so:
Xtest＝2π·Bmω0cosω0t·Stest
Xstd＝2π·Bmω0cosω0t·Sstd
wherein, XtestAnd XstdFor the coil to be measured and the standard coil in the single-side amplitude spectrum omega ═ omega0The equivalent induction area of the coil of the probe to be measured can be obtained as follows:
Figure BDA0002845493290000035
further, when the areas of a plurality of probe coils are calibrated simultaneously, a plurality of positions where the coil to be tested is placed are determined within +/-20 cm of the center of the coil and are recorded as A, B, C … …, the current source output is kept unchanged before calibration, the standard coil is placed at positions A, B, C and the like, and the ratio of the magnitude of the output signal of the standard coil at the positions A, B, C and the like to the magnitude of the output signal of the original position of the standard coil is recorded as XA、XB、XCSimultaneously acquiring voltage values output by the standard coil and the probe coils, respectively calculating the areas of the probe coils, and respectively multiplying the equivalent areas of the coils at the A, B, C … … positions by a coefficient X after the measurement is finishedA、XB、XC… …, the equivalent area of the final coil.
Has the advantages that:
the invention can quickly realize the calibration of the equivalent induction area of the probe under simple laboratory conditions, and provides a feasible method for large-batch probe calibration, for example, two hundred magnetic probes in an EAST device are calibrated by using the method of the invention.
Furthermore, by means of simply lengthening the length and the number of turns of the solenoid and calibrating the relative strength of the magnetic field at different positions in the solenoid, the simultaneous calibration of a plurality of probes to be tested can be realized, and the working efficiency can be further improved.
In addition, all probes to be detected are calibrated by using the same standard probe, so that the consistency of all probes is ensured.
In the method, the probe to be detected and the standard probe are positioned in the same alternating magnetic field, so that the measurement error caused by instability of the alternating magnetic field due to power supply fluctuation and the like can be eliminated, and the calibration precision of the equivalent area of the probe can reach within 1 per thousand.
Drawings
FIG. 1: the invention is a schematic diagram of a whole calibration system;
FIG. 2: the sinusoidal current source used in the invention;
FIG. 3: the voltage acquisition equipment used in the invention;
FIG. 4: the long straight solenoid used in the present invention;
FIG. 5: the coil fixing clamp used in the invention;
FIG. 6: calibrating a standard probe required by the system;
FIG. 7: voltage waveforms output by the standard probe and the probe to be detected, and a single-side amplitude spectrum obtained after fast Fourier transform.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.
Fig. 1 shows a system for calibrating an equivalent induction area of a high-precision probe coil based on an alternating magnetic field, which includes a current source, a high-power winding fixed resistor (2000W, 10 Ω), a long straight solenoid (the solenoid employed in the invention is 1 meter long, the number of turns of the coil is 248 turns, the length and the number of turns can be increased according to the requirement), a coil fixing clamp, a standard coil and an NI portable voltage acquisition device; one end output of the current source is connected to a power resistor, and the fixed resistor is connected with the other end of the current source in series to form a loop; and the standard coil and the coil to be detected are respectively fixed on the coil fixing clamp, and the two coils are symmetrically arranged at equal intervals from the center of the solenoid. And the two ends of the standard coil and the coil to be detected are respectively connected to the two acquisition ports of the voltage acquisition equipment, and the output voltages of the standard coil and the coil to be detected are acquired simultaneously.
FIG. 2 shows a frequency-amplitude adjustable sinusoidal current source used in the present system, which can achieve an output above the peak-to-peak value 3A when the operating frequency is 100-500 Hz.
Fig. 3 shows NI voltage acquisition devices adopted by the system, which are cDAQ-9174 and NI 9215, and are used in combination to realize simultaneous acquisition of 16 paths of voltage signals.
Fig. 4 shows that the long straight solenoid designed and manufactured by the system has the length of 1 meter and the number of turns of the coil of 248 turns, and the calculation and measurement show that the magnetic field is uniformly distributed near the central position. The length of the solenoid and the number of coil turns can be increased or decreased according to the requirements of a specific system, but considering that the increase of the number of coil turns can increase the loop inductance, the output power of the power supply is limited, and the length of the solenoid and the number of coil turns can not be increased without limitation.
Fig. 5 is a coil fixing clamp designed by the present invention, which ensures that the relative positions of the probe coil to be tested, the standard coil and the solenoid coil are fixed and symmetrically distributed on two sides of the central section of the solenoid coil. The coil fixing clamp comprises a coil fixing base, a plurality of coil adjusting supports are arranged on the coil fixing base, the coil adjusting supports are arranged along the center line of the solenoid in a bilateral symmetry mode, and a push-pull handle is arranged at the front end of the coil fixing base.
Fig. 6 is a standard coil (i.e., a standard probe coil) used in the present invention, which itself has been calibrated with high precision.
Fig. 7 shows voltage waveforms output by the standard probe and the coil of the probe to be tested, and a single-side frequency spectrum obtained after fast fourier transform. The Y-axis numerical value corresponding to the highest point of the single-side amplitude spectrum is the amplitude of the single-side amplitude spectrum when the frequency is the same as the power frequency.
The power supply is a sinusoidal alternating current source, so the current in the solenoid is sinusoidal alternating current, and the magnetic field in the solenoid is:
B＝Bm sinω0t
wherein, BmIs the maximum value of the magnetic field, ω0The angular frequency of the sinusoidal alternating current in the solenoid. From the change in the magnetic field one can obtain:
Figure BDA0002845493290000051
Figure BDA0002845493290000052
wherein epsilontest(t) is the voltage value at two ends of the coil of the probe to be measured, phitestIs the magnetic flux of the probe coil to be measured, StestThe equivalent area of the probe coil to be detected; epsilonstd(t) is the voltage across the reference coil, phistdIs the magnetic flux of a standard coil, SstdEquivalent area for standard coil:
Figure BDA0002845493290000053
Figure BDA0002845493290000054
wherein
Figure BDA0002845493290000055
And
Figure BDA0002845493290000056
is epsilontest(t) and εstd(t) fourier transform, so:
Xtest＝2π·Bmω0cosω0t·Stest
Xstd＝2π·Bmω0cosω0t·Sstd
wherein, XtestAnd XstdFor the coil to be measured and the standard coil in the single-side amplitude spectrum omega ═ omega0The amplitude of (d) is measured. Therefore, the equivalent induction area of the probe coil to be tested is as follows:
Figure BDA0002845493290000057
although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but various changes may be apparent to those skilled in the art, and it is intended that all inventive concepts utilizing the inventive concepts set forth herein be protected without departing from the spirit and scope of the present invention as defined and limited by the appended claims.

Claims (9)

1. The utility model provides a system based on alternating magnetic field coil equivalent induction area is markd which characterized in that: the device comprises a current source, a fixed resistor, a long straight solenoid, a coil fixing clamp, a standard coil and a voltage acquisition device; one end output of the current source is connected to a power resistor, and the fixed resistor is connected with the other end of the current source in series to form a loop; the standard coil and the coil to be detected are respectively fixed on the coil fixing clamp; the coil fixing clamp is placed in the long straight solenoid, so that the positions of the standard coil and the coil to be detected are symmetrical relative to the center of the long straight solenoid, the two ends of the standard coil and the two ends of the coil to be detected are connected to the two acquisition ports of the voltage acquisition equipment respectively, and the output voltages of the standard coil and the coil to be detected are acquired simultaneously.
2. The system of claim 1, wherein the system comprises:
the number of the probe coils to be detected is one or more, and the probe coils can be simultaneously fixed at different positions of the coil fixing clamp for simultaneous measurement; the output voltage of each probe coil is connected to a different voltage acquisition port of a voltage acquisition device.
3. The system of claim 1, wherein the system comprises:
the fixed resistor is a high-power resistor, the resistor is 5-20 ohms, and the power is 1000-5000 watts.
4. The system of claim 1, wherein the system comprises:
the current source is a sinusoidal current source with adjustable frequency and amplitude, and can realize current output above the peak value of 3A when the working frequency is 100-500 Hz.
5. The system of claim 1, wherein the system comprises:
the length of the long straight solenoid is 500mm-1500mm, the long straight solenoid can be adjusted according to the number of the probe coils to be measured, and more coils can be measured simultaneously by increasing the length and the number of turns of the solenoid.
6. The system of claim 1, wherein the system comprises:
the coil fixing clamp ensures that the relative positions of a probe coil to be detected, a standard coil and a solenoid are fixed and are symmetrically distributed on two sides of the central section of the solenoid, the coil fixing clamp comprises a coil fixing base, a plurality of coil adjusting supports are arranged on the coil fixing base and are arranged in a bilateral symmetry mode along the central line of the solenoid, and a push-pull handle is arranged at the front end of the coil fixing base.
7. A method for equivalent induction area calibration based on alternating magnetic field coils, using the system of any one of claims 1-6, comprising the steps of:
step 1, fixing a probe coil to be detected and a standard coil on a coil fixing clamp;
step 2, adjusting the current of the current source according to the equivalent area of the probe coil to be detected and the standard coil, so that the output voltages of the probe coil to be detected and the standard coil are matched with the acquisition equipment;
step 3, starting a current source to supply power to the solenoid and the resistor series loop;
step 4, collecting the voltage epsilon at two ends of the coil of the probe to be detected through voltage collecting equipmenttest(t) and the voltage ε at both ends of the standard coilstd(t)；
Step 5, respectively carrying out Fourier decomposition on the two collected voltage waveforms to obtain the amplitude values of the single-side amplitude spectrum at the corresponding frequency; calculating the equivalent induction area S of the probe coil to be detected:
Figure FDA0002845493280000021
wherein S isstdIs the equivalent induction area, X, of a standard coiltestAnd XstdThe amplitudes of the coil to be detected and the standard coil output voltage at the corresponding frequency are respectively.
8. The method according to claim 7, wherein the method comprises the following steps:
the power supply is a sinusoidal alternating current source, so the current in the solenoid is sinusoidal alternating current, and the magnetic field in the solenoid is:
B＝Bm sin ω0t
wherein, BmIs the maximum value of the magnetic field, ω0Is the angular frequency of the sinusoidal alternating current in the solenoid; from the change in the magnetic field:
Figure FDA0002845493280000022
Figure FDA0002845493280000023
wherein epsilontest(t) is the voltage value at two ends of the coil of the probe to be measured, phitestIs the magnetic flux of the coil to be measured, StestThe equivalent area of the coil to be measured; epsilonstd(t) is the voltage across the coil of the standard probe, phistdIs the magnetic flux of a standard coil, SstdEquivalent area for standard coil:
Figure FDA0002845493280000024
Figure FDA0002845493280000025
wherein
Figure FDA0002845493280000026
And
Figure FDA0002845493280000027
is epsilontest(t) and εstdFourier transform of (t), so
Xtest＝2π·Bmω0cosω0t·Stest
Xstd＝2π·Bmω0coSω0t·Sstd
Wherein, XtestAnd XstdFor the coil to be measured and the standard coil in the single-side amplitude spectrum omega ═ omega0The equivalent induction area of the coil of the probe to be measured can be obtained as follows:
Figure FDA0002845493280000031
9. the method according to claim 7, wherein the method comprises the following steps:
when the areas of a plurality of probe coils are calibrated simultaneously, a plurality of positions where the coil to be detected is placed are determined within +/-20 cm of the center of the coil and recorded as A, B, C … …, the output of a current source is kept unchanged before calibration, a standard coil is placed at positions A, B, C and the like, the ratio of the output signal of the standard coil at the positions A, B, C and the like to the original position of the standard coil is recorded and recorded as XA、XB、XCAcquiring voltage values output by a standard coil and a plurality of probe coils simultaneously in the calibration process, calculating the areas of the plurality of probe coils respectively, and multiplying the equivalent area of the coil placed at the position A, B, C … … by a coefficient X respectively after the measurement is finishedA、XB、XC… …, the equivalent area of the final coil.
CN202011508051.7A 2020-12-18 2020-12-18 System and method based on alternating magnetic field coil equivalent induction area calibration Pending CN112578329A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114062991A (en) * 2021-12-10 2022-02-18 湖南常德牌水表制造有限公司 Detection method and system of switch type Hall sensor
CN114184989A (en) * 2021-12-01 2022-03-15 中国科学院合肥物质科学研究院 Magnetic probe amplitude-frequency and phase-frequency calibration system and method based on Helmholtz coil
CN116087838A (en) * 2023-02-10 2023-05-09 中国计量科学研究院 Bridge circuit-based strong magnetic field measuring device and measuring method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114184989A (en) * 2021-12-01 2022-03-15 中国科学院合肥物质科学研究院 Magnetic probe amplitude-frequency and phase-frequency calibration system and method based on Helmholtz coil
CN114062991A (en) * 2021-12-10 2022-02-18 湖南常德牌水表制造有限公司 Detection method and system of switch type Hall sensor
CN116087838A (en) * 2023-02-10 2023-05-09 中国计量科学研究院 Bridge circuit-based strong magnetic field measuring device and measuring method
CN116087838B (en) * 2023-02-10 2023-08-22 中国计量科学研究院 Bridge circuit-based strong magnetic field measuring device and measuring method

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