CN109839610A - Helmholtz coil constant exchange calibration system and method based on orthogonality principle - Google Patents
Helmholtz coil constant exchange calibration system and method based on orthogonality principle Download PDFInfo
- Publication number
- CN109839610A CN109839610A CN201811616067.2A CN201811616067A CN109839610A CN 109839610 A CN109839610 A CN 109839610A CN 201811616067 A CN201811616067 A CN 201811616067A CN 109839610 A CN109839610 A CN 109839610A
- Authority
- CN
- China
- Prior art keywords
- induced voltage
- curve
- exciting current
- current
- helmholtz coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Measuring Magnetic Variables (AREA)
Abstract
A kind of Helmholtz coil constant exchange calibration system and method based on orthogonality principle, this method comprises: generating different frequency sine wave AC signal using arbitrary waveform generator；Sine wave AC signal is amplified and is sent to Helmholtz coil by power amplifier, it is made to generate AC excitation signal；Digital power meter acquires the induced voltage of the small coil of known circle area and the exciting current by Helmholtz coil；The product P' of induced voltage and exciting current is calculated to induced voltage and exciting current according to the first computation rule, and induced voltage and exciting current are calculated according to the second computation rule the product Q' of induced voltage and exciting current；And induced voltage virtual value U is calculated using orthogonality principlerms；Based on induced voltage virtual value UrmsWith exciting current virtual value Irms, calculate Helmholtz coil constant.It is accurate to determine induced voltage virtual value so as to remove the spurious signal in induced voltage, improve the accuracy of measurement.
Description
Technical field
The invention belongs to the field that accurately measures of magnetic moment, in particular to a kind of Helmholtz coil constant exchange calibration system
System and method.
Background technique
Germany scientist Helmholtz devised Helmholtz coil in 1849.Helmholtz coil is usually by a pair
Circular coil series aiding connection forms, and for generating, intensity is lower, the biggish uniform magnetic field of range.By calibrated Helmholtz
Coil is connect with a calibrated magnetic flux integrator, can be used for the accurate measurement of magnetic moment.
Fig. 1 shows the open circuit measurement device of Helmholtz coil.Package unit is put into without in ferromagnetic environment, most
It is placed into well on the wooden desk.As shown, magnet is placed on when measurement the center (homogeneity range) of coil, the magnetization of magnet
Intensity is along the x-axis direction, i.e., axial parallel with coil.Two coil signals to get up are connected in series and are transferred directly to fluxmeter.It adjusts
After saving fluxmeter zero point, magnet is removed coil, keeps it parallel with coil axis.The distance of removal is usually 75~100cm, this
It is that sample is allowed not influence reading that sample, which is done,.Pass through the integral (magnetic flux) of current versus time, it can obtain the open circuit magnetic of sample
Square.Another measurement method is that sample rotates 180 degree is not had to sample to take out, and the voltage generated in this way will be original
2 times, then coil constant will be original 1/2.Both methods is mentioned in IEC60404-14 standard.It is magnetized when one
Sample pulled out from a Helmholtz coil come when, the dipole moment of sample can be determined by following formula:
J=Δ φ/kh (1.1)
In formula: j is dipole moment, and unit is weber rice (Wbm)；khFor Helmholtz coil constant, magnetic field strength with
The ratio between electric current kh=H/I, unit are every meter of every peace (A/m/A) of peace；Δ φ is that sample is rotated or pulled out in search coil
When, flux change amount, unit is weber (Wb)；H is magnetic field strength, and unit is ampere per meter (A/m) (A/m)；I is current strength, single
Position is ampere (A).
When sample is when search coil center rotates 180 °, formula (1.1) is evolved into:
J=ΔΦ/2kh (1.2)
Magnetic flux integrator be rotate in search coil by measuring sample or is therefrom pulled out come during it is produced
Induced voltage variation, and then measure magnetic flux.The mode of standard mutual inductor or weber generator can be used to carry out school for magnetic flux integrator
It is quasi-.
Helmholtz coil needs to calibrate before use.Helmholtz coil should ensure that its homogeneity range covering sample to be tested
Shape and volume.Coil constant (magnetic field strength and current strength ratio) k of Helmholtz coilhLine can be flowed through by measurement
It the electric current of circle and is obtained with the magnetic field strength at field detecting device measuring coil center.Since current strength is easier to reality
Existing high-precision measurement, therefore the calibration method technological difficulties of conventional Helmholtz coil are concentrated mainly on hub of a spool
The accurate measurement of magnetic field strength.
Currently, space magnetic field measurement majority is the instrument using Hall effect, while this is also that IEC60404-14 suggests
The method used.In industrial application, the Hall effect magnetometer of reliable performance is can be used in the calibration of Helmholtz coil completely
It realizes, however for establishing national measurement standard, it is clear that traceability of the gaussmeter of Hall effect in required magnetic field range is not
It is able to satisfy requirement.
Nucleus-magnetism-resonance magnetometer does not have the directionality of hall probe sensitivity, and its accuracy can achieve 5ppm, is magnetic
Field measurement the recognized standard, but general nucleus-magnetism-resonance magnetometer requires the magnetic field range of measurement, the minimum magnetic field of measurement
Generally in 500Oe or so, Helmholtz coil cannot generally generate so big magnetic field.
The prior art one calibrates Helmholtz coil, optical pumping magnetic strength by optically pumped magnetometer and zero magnetic field space environment
Meter realizes the precise measurement to magnetic field using the Zeemen effect of atom.When calibrating Helmholtz coil using optically pumped magnetometer,
Since its maximum field measurement range is 1Gs, earth's magnetic field and other spaces stray magnetic field etc. all can largely influence
Measurement accuracy.In order to solve this problem, zero magnetic field space (as shown in Figure 2) need to be built, current method is to pass through large-scale three dimensional
Combined type Helmholtz coil is realized, the amplitude of all directions environment field can be dropped to 3nT or less.Because of Helmholtz coil
The magnetic field of generation is very small, generally in (10-100) Gs or so, at this time earth's magnetic field, stray magnetic field, measurement under the electric current of permission
The zero point of instrument can all carry out very big influence to calibration tape, and for the uncertainty of calibration generally 0.3% or so, uncertainty is higher.
The prior art two, using Low Magnetic field MRI instrument calibration Helmholtz coil, Low Magnetic field MRI instrument is capable of providing
About several oersteds are accurately measured to the magnetic field of 150 oersteds, and uncertainty is especially suitable for Helmholtz coil in 5-10ppm
Calibration.Low Magnetic field MRI instrument includes NMR Magnetometer Using Flowing Water and the free resonant magnetometer of electronics, past, the U.S.
GMW company production continuous-flow type nuclear magnetic resonance apparatus, model FW101, but since core technology is not inherited, this instrument mesh
Preceding GMW is suspended sale of, and other countries are also without product in the world.There is the free resonance probe sale of electronics on the website Metrolab, matches
The Nuclear Magnetic Resonance Measurement instrument for closing probe Metrolab can accurately measure low field magnetic field.However actually also due to technology
And problem of materials, the probe is at present in the world also without salable item.It is suitble to the continuous-flow type nuclear magnetic resonance magnetic strength of direct current method calibration
It can not be purchased in the instrument markets such as meter, electronic spin resonance magnetometer.
Problems of the prior art,
1, the calibration method of optically pumped magnetometer and zero magnetic field space environment, measurement result interfered signal shadow are used at present
Sound is larger, and measurement result accuracy rate is lower.
2, at present using NMR Magnetometer Using Flowing Water, the electronic spin resonance magnetometer etc. for being suitble to direct current method calibration
It can not be purchased in instrument market, accurate measurement is difficult to be realized.
Summary of the invention
(1) goal of the invention
The object of the present invention is to provide a kind of Helmholtz coil constants to exchange calibration method, apparatus and system.On the one hand
The influence for avoiding interference signal improves the accuracy rate of measurement result.On the other hand the calibrating installation design used is simple and convenient,
It accurately measures easy to accomplish.
(2) technical solution
To solve the above problems, the first aspect of the embodiment of the present invention provides a kind of Hai Muhuo based on orthogonality principle
Hereby coil constant exchanges calibration method, and using a kind of calibrating installation, which includes: sequentially connected random waveform hair
Raw device, power amplifier, Helmholtz coil and digital power meter；The power amplifier also connects with the digital power meter
It connects, the Helmholtz coil includes the concentric circular coil of a pair of of series aiding connection；The central homogeneity range of the Helmholtz coil
Inside it is placed with small coil；The calibration method includes: the sine wave AC letter that different frequency is generated using arbitrary waveform generator
Number；The sine wave AC signal is amplified and is sent to the Helmholtz coil by power amplifier, makes the Helmholtz
Coil generates AC excitation signal；Under the action of the AC excitation signal, digital power meter acquires the small of known circle area
The induced voltage U of coil and exciting current I by the Helmholtz coil；According to the first computation rule to the induction
The product P' of induced voltage and exciting current is calculated in voltage and the exciting current, and according to the second computation rule pair
The product Q' of induced voltage and exciting current is calculated in the induced voltage and the exciting current, and is based on induced voltage
It with the product P' and product Q' of exciting current, is calculated using orthogonality principle, obtains induced voltage virtual value Urms；Based on sense
The product P' and product Q' for answering voltage and exciting current, are calculated using orthogonality principle, obtain induced voltage virtual value
Urms；Based on the induced voltage virtual value UrmsWith exciting current virtual value Irms, Helmholtz coil constant is calculated.
Further, described that sense is calculated to the induced voltage and the exciting current according to the first computation rule
Answer the product P' of voltage and exciting current, comprising: induced voltage curve and magnetizing current curve are obtained using digital power meter；
Induced voltage data point is acquired from the voltage curve；The current curve is encouraged along horizontal axis first numerical value that moves right
Magnetoelectricity fluxion strong point, so that there are first phase differences between current curve and original current curve after mobile；Based on the electricity
Corresponding exciting current data point on the current curve after the induced voltage data point and movement buckled on line, point-by-point phase
Multiply and product P' is calculated.
Further, based on the current curve after the induced voltage data point and movement on the voltage curve
Product P' is calculated in corresponding exciting current data point, point-by-point be multiplied, comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+x indicates that voltage data point is to the right on induced voltage curve
Number after mobile x numerical point, n are the sum of voltage data point on voltage curve, UiIt is the small coil of known circle area
Induced voltage, IiIt is by the exciting current of the Helmholtz coil, φ is induced voltage virtual value UrmsWith excitation electricity
Flow IrmsPhase angle.
Further, described that sense is calculated to the induced voltage and the exciting current according to the second computation rule
Answer the product Q' of voltage and exciting current, comprising: induced voltage curve and magnetizing current curve are obtained using digital power meter；
Induced voltage data point is acquired from the voltage curve；The current curve is moved into second value point excitation along horizontal axis
Current data point, so that there are second phase between current curve and original current curve after mobile poor, the second phase
The poor difference between the first phase difference is less than or equal to a cycle；Based on the induced voltage on the voltage curve
Product Q' is calculated in corresponding exciting current data point on the current curve after data point and movement, point-by-point be multiplied.
Further, based on the current curve after the induced voltage data point and movement on the voltage curve
Product Q' is calculated in corresponding exciting current data point, point-by-point be multiplied, comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+y indicates that voltage data point is to the right on induced voltage curve
Number after mobile y numerical point, y-x are less than or equal to a cycle, and n is the sum of voltage data point on voltage curve,
UiIt is the induced voltage of the small coil of known circle area, IiIt is by the exciting current of the Helmholtz coil, φ is induction
Voltage effective value UrmsWith exciting current IrmsPhase angle.
Further, product P' and product Q' based on induced voltage and exciting current, are counted using orthogonality principle
It calculates, obtains induced voltage virtual value Urms, specifically it is calculated in accordance with the following methods:
In formula, IrmsFor exciting current virtual value, UrmsFor induced voltage virtual value, phase difference of the φ between product P' and product Q',
sinφy-xWith cos φy-xIt is constant.
Further, the exciting current virtual value IrmsCalculation it is as follows:In formula, j table
Show the number of current data point on current curve, m is the sum of current data point on current curve.
Further, described to be based on the induced voltage virtual value UrmsWith the exciting current I, Hai Muhuo is calculated
Hereby coil constant is specifically calculated in accordance with the following methods:In formula: UrmsIt is small coil-induced
Voltage effective value, f are signal source frequency, and NS is circle area, μ known to small coil0For magnetic constant, khIt is normal for Helmholtz coil
Number, IrmsTo pass through the current effective value of Helmholtz coil.
It is normal to provide a kind of Helmholtz coil based on orthogonality principle for other side according to an embodiment of the present invention
Number exchange calibration system, comprising: sine wave AC signal generation apparatus, for generating the sine wave AC signal of different frequency；
Power amplifier makes Helmholtz's line for amplifying and being sent to Helmholtz coil for the sine wave AC signal
Circle generates AC excitation signal；Digital power meter, under the action of the AC excitation signal, acquiring known circle area
The induced voltage that generates of small coil and exciting current by the Helmholtz coil；Induced voltage virtual value calculates mould
Block, for induced voltage and excitation electricity to be calculated to the induced voltage and the exciting current according to the first computation rule
The product P' of stream, and induced voltage is calculated to the induced voltage and the exciting current according to the second computation rule
With the product Q' of exciting current, and product P' and product Q' based on induced voltage and exciting current, carried out using orthogonality principle
It calculates, obtains induced voltage virtual value Urms；Coil constant computing module, for being based on the induced voltage virtual value UrmsWith
Exciting current virtual value Irms, Helmholtz coil constant is calculated.
Further, the induced voltage virtual value computing module, comprising: acquisition submodule, for obtaining induced voltage
Curve and magnetizing current curve；Induced voltage data point acquires submodule, for acquiring induced voltage from the voltage curve
Data point；First movement submodule, for the current curve to move right the first numerical value exciting current data along horizontal axis
Point, so that there are first phase differences between current curve and original current curve after mobile；First computational submodule, is used for
Based on corresponding exciting current data on the current curve after the induced voltage data point and movement on the voltage curve
Product P' is calculated in point, point-by-point be multiplied.
Further, the product P' of induced voltage and exciting current is calculated according to following formula, comprising:Wherein, i indicates the number of voltage data point on induced voltage curve, and i+x indicates sense
Voltage data point on voltage curve is answered to move right the number after x numerical point, n is voltage data point on voltage curve
Sum, UiIt is the induced voltage of the small coil of known circle area, IiIt is by the exciting current of the Helmholtz coil, φ is
Induced voltage virtual value UrmsWith exciting current IrmsPhase angle.
Further, the induced voltage virtual value computing module, comprising: the acquisition submodule, for obtaining induction
Voltage curve and magnetizing current curve；The induced voltage data point acquires submodule, for acquiring from the voltage curve
Induced voltage data point；Second mobile submodule, for the current curve to be moved second value point excitation electricity along horizontal axis
Fluxion strong point, so that there are second phase between current curve and original current curve after mobile is poor, the second phase is poor
Difference between the first phase difference is less than or equal to a cycle；Second computational submodule, for being based on the voltage
Corresponding exciting current data point on the current curve after induced voltage data point and movement on curve, is calculated
Product Q'.
Further, the product Q' of induced voltage and exciting current is calculated according to following formula, comprising:Wherein, i indicates the number of voltage data point on induced voltage curve, i+y
Indicate the number that voltage data point moves right after y numerical point on induced voltage curve, y-x is less than or equal to a week
Phase, n are the sum of voltage data point on voltage curve, UiIt is the induced voltage of the small coil of known circle area, IiIt is to pass through institute
The exciting current of Helmholtz coil is stated, φ is induced voltage virtual value UrmsWith exciting current IrmsPhase angle.
Further, product P' and product Q' based on induced voltage and exciting current, are counted using orthogonality principle
It calculates, obtains induced voltage virtual value Urms, comprising:In formula, IrmsFor excitation electricity
Flow virtual value, UrmsFor induced voltage virtual value, phase difference of the φ between product P' and product Q', sin φy-xWith cos φy-x
It is constant.
Further, the exciting current virtual value IrmsCalculation it is as follows:In formula, j table
Show the number of current data point on current curve, m is the sum of current data point on current curve.
Further, Helmholtz coil constant is calculated in coil constant computing module in accordance with the following methods:In formula: UrmsFor small coil-induced voltage effective value, f is signal source frequency, and NS is small coil
Known circle area, μ0For magnetic constant, khFor Helmholtz coil constant, IrmsIt is effective by the electric current of Helmholtz coil
Value.
(3) beneficial effect
Above-mentioned technical proposal of the invention has following beneficial technical effect:
First, using calibrating installation and calibration method of the invention, based on the induced voltage and the exciting current point
The product P' and product Q' of induced voltage and exciting current are not calculated, is calculated using orthogonality principle, obtains induced electricity
It is pressed with valid value Urms.The spurious signal in induced voltage can effectively be removed, to accurately determine the virtual value of induced voltage, mentioned
The accuracy of high measurement.
Second, calibrating installation of the invention uses arbitrary waveform generator, power amplifier, Helmholtz coil, number
Power meter and small coil, the above instrument can be bought from the market, and design is simple, and easy to operate, more acurrate measurement voltage is effective
Value.
Detailed description of the invention
Fig. 1 is the permanent magnetism magnetic moment measurement method schematic diagram of magnetic flux integrator and Helmholtz coil in the prior art；
Fig. 2 is the zero magnetic field space schematic diagram that large-scale three dimensional combined type Helmholtz coil is built in the prior art；
Fig. 3 is the structure of the Helmholtz coil constant exchange calibrating installation in the embodiment of the present invention based on orthogonality principle
Schematic diagram；
Fig. 4 is the calibration method flow chart in the embodiment of the present invention；
Fig. 5 is the structural schematic diagram of the calibration system in the embodiment of the present invention；
Fig. 6 is the structural schematic diagram of induced voltage virtual value computing module in the embodiment of the present invention；
Fig. 7 is the structural schematic diagram of induced voltage virtual value computing module in the embodiment of the present invention.
Appended drawing reference:
1- arbitrary waveform generator, 2- power amplifier, 3- Helmholtz coil, 4- digital power meter, the small coil of 5-,
6- sine wave AC signal generation apparatus, 7- induced voltage virtual value computing module, 71- acquisition submodule, 72- induced voltage
Data point acquires submodule, 73- first movement submodule, the first computational submodule of 74-, the second mobile submodule of 75-, 76- the
Two computational submodules, 8- coil constant computing module.
Specific embodiment
In order to make the objectives, technical solutions and advantages of the present invention clearer, With reference to embodiment and join
According to attached drawing, the present invention is described in more detail.It should be understood that these descriptions are merely illustrative, and it is not intended to limit this hair
Bright range.In addition, in the following description, descriptions of well-known structures and technologies are omitted, to avoid this is unnecessarily obscured
The concept of invention.
Embodiment one
Fig. 3 is a kind of Helmholtz coil constant exchange calibrating installation based on orthogonality principle in the present embodiment.
As shown in figure 3, the calibrating installation includes: sequentially connected arbitrary waveform generator 1, power in the present embodiment
Amplifier 2, Helmholtz coil 3 and digital power meter 4.The power amplifier 2 is also connected with the digital power meter 4, institute
State the concentric circular coil that Helmholtz coil 3 includes a pair of of series aiding connection.In the central homogeneity range of the Helmholtz coil 3
It is placed with small coil 5.Specifically, the power amplifier 2 uses AE Techron 7548P high stability power amplifier 2,
Stable electric current is provided for calibration Helmholtz coil 3.Peak power output: 3300w rms, output frequency: DC-
200kHz, DC Drift: ± 200 μ V.Arbitrary waveform generator 1 uses Agilent 33500B arbitrary waveform generator 1, for height
Stability power amplifier 2 provides signal source, total harmonic distortion 0.04%.Instrument used by the present apparatus can be in market
Upper buying, it is easy to operate easy to accomplish.The digital power meter 4 accurately measures the induction of small coil 5 using LMG610 power meter
Voltage and exciting current.Specifically, the digital power meter 4 is equipped with sensor, the sense of small coil 5 can be directly measured
Answer voltage.The input voltage range of sensor: 0-4V.The limits of error: ± (+0.02% full scale of 0.01% measured value).
Preferably, the 5 place plane of small coil and the 3 place plane of Helmholtz coil are in a predetermined angle, institute
State angle adjustable.Specifically, the angular configurations range are as follows: 0-90 degree.Helmholtz coil 3 is calibrated with small coil 5, is examined
The collimation for considering small coil 5 plane and Helmholtz coil 3 also needs to pass through fine tuning on the basis of Machine Design ensures parallel
Maximum induced voltage signal is found, to realize minimum calibration uncertainty.The present embodiment devises small 5 angular adjustment of coil
Function is capable of the angle of universal adjustment small 5 plane of coil and 3 plane of Helmholtz coil, finds maximum induced voltage signal
Afterwards, angle can be locked, to improve the accuracy of calibration.Test data shows that this method can reach ambient noise deduction rate
To 99% or so, orthogonal calculation rear backdrop noise falls below 0.005% level to the influence of voltage measurement.
Calibration method flow chart in Fig. 4 embodiment of the present invention.
As shown in figure 4, the calibration method includes: S1: generating the sine of different frequency using arbitrary waveform generator 1
Wave AC signal；S2: the sine wave AC signal is amplified and is sent to the Helmholtz coil 3 by power amplifier 2,
The Helmholtz coil 3 is set to generate AC excitation signal；S3: under the action of the AC excitation signal, digital power meter
4 acquire the induced voltage U of the small coil 5 of known circle area and the exciting current I by the Helmholtz coil 3；S4: root
The induced voltage and the exciting current are calculated according to the first computation rule the product of induced voltage and exciting current
P', and induced voltage and excitation electricity are calculated to the induced voltage and the exciting current according to the second computation rule
The product Q' of stream；S5: product P' and product Q' based on induced voltage and exciting current are calculated using orthogonality principle, are obtained
To induced voltage virtual value Urms；S6: it is based on the induced voltage virtual value UrmsWith exciting current virtual value Irms, it is calculated
Helmholtz coil constant.
In the present embodiment, the induced voltage of small coil 5 contains useful signal and spuious field signal, directly measures it
Virtual value can bring very big uncertainty.Because only including assigned frequency signal in current signal, digital power meter 4 is used
The product P' and product Q' for calculating separately inductive voltage and current can remove spuious in induced voltage according to orthogonality principle
Signal improves the accuracy of measurement, sees formula (1.3) (1.4) (1.5) so as to accurately determine induced voltage virtual value.
Helmholtz coil 3 leads to constant sine-wave current, is placed on Hai Muhuo using the small coil 5 of known circle area
Hereby 3 center of coil accurately measures small 5 induced voltage of coil, to calculate coil constant, sees formula (2.1).It can from formula
To find out, kh5 circle of exciting current, frequency and small coil generated from induced voltage, the Helmholtz coil 3 of small coil 5
Area, wherein electric current and frequency can be determined accurately.Therefore, the key factor of alternating current method calibration is small 5 circle area NS of coil
Can the voltage effective value signal under uncertainty and space astray field influence Accurate Determining.
Urms=2 π fNS μ0·kh·Irms (2.1)
Wherein: UrmsFor small coil-induced voltage effective value, f is signal source frequency, and NS is circle area, μ known to small coil0
For magnetic constant, khFor Helmholtz coil constant, IrmsTo pass through the current effective value of Helmholtz coil.
Arbitrary waveform generator 1 provides the sine wave AC signal of different frequency, and power amplifier 2 is by sine wave AC
Signal is amplified to suitable intensity and is placed in Hai Muhuo under the excitation of alternating magnetic field to 3 AC excitation of Helmholtz coil
Hereby the small coil 5 in the central homogeneity range of coil 3 generates induced voltage signal, this induced voltage signal is sent to digital power meter 4
Voltage sensor end accurately measure voltage.
Wherein, according to the first computation rule to the induced voltage and the exciting current be calculated induced voltage with
The product P' of exciting current, comprising: induced voltage curve and magnetizing current curve are obtained using digital power meter；From the electricity
It buckles and acquires induced voltage data point on line；The current curve is moved right the first numerical value exciting current number along horizontal axis
Strong point (such as: move right 100 exciting current data points) so that after mobile current curve and original current curve it
Between there are first phase differences；Based on the current curve after the induced voltage data point and movement on the voltage curve
Product P' is calculated in corresponding exciting current data point, point-by-point be multiplied.Specifically sense is calculated according to following formula
Answer voltage and exciting current product P', comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+x indicates voltage number on induced voltage curve
Strong point moves right the number after x numerical point, and n is the sum of voltage data point on voltage curve, UiIt is known circle area
Small coil 5 induced voltage, IiIt is by the exciting current of the Helmholtz coil 3, φ is induced voltage virtual value
UrmsWith exciting current IrmsPhase angle.
Wherein, according to the second computation rule to the induced voltage and the exciting current be calculated induced voltage with
The product Q' of exciting current, comprising: induced voltage curve and magnetizing current curve are obtained using digital power meter 4；From the electricity
It buckles and acquires induced voltage data point on line；The current curve is moved into second value point exciting current data along horizontal axis
Point (such as: move right 300 exciting current data points) so that after mobile between current curve and original current curve
It is poor that there are second phase, and the difference between the second phase difference and the first phase difference is less than or equal to a cycle；Base
Corresponding exciting current data on the current curve after the induced voltage data point and movement on the voltage curve
Product Q' is calculated in point, point-by-point be multiplied.Specifically, multiplying for induced voltage and exciting current is calculated according to following formula
Product Q', comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+y indicates voltage number on induced voltage curve
Strong point moves right the number after y numerical point, and y-x is less than or equal to a cycle, and n is voltage data on voltage curve
The sum of point, UiIt is the induced voltage of the small coil 5 of known circle area, IiIt is the excitation electricity by the Helmholtz coil 3
Stream, φ is induced voltage virtual value UrmsWith exciting current IrmsPhase angle.
Wherein, product P' and product Q' based on induced voltage and exciting current, are calculated using orthogonality principle, are obtained
To induced voltage virtual value Urms, specifically it is calculated in accordance with the following methods:
In formula, IrmsFor exciting current virtual value, UrmsFor induced voltage virtual value, φ is between product P' and product Q'
Phase difference, sin φy-xWith cos φy-xIt is constant.
Wherein, exciting current virtual value IrmsCalculation it is as follows:
In formula, j indicates the number of current data point on current curve, and m is the sum of current data point on current curve.
Wherein, it is based on the induced voltage virtual value UrmsWith the exciting current I, it is normal that Helmholtz coil is calculated
Number, is specifically calculated in accordance with the following methods:
In formula: UrmsFor small coil-induced voltage effective value, f is signal source frequency, and NS is circle area, μ known to small coil0
For magnetic constant, khFor Helmholtz coil constant, IrmsTo pass through the current effective value of Helmholtz coil.
In the present embodiment, migration current obtains P' and Q' to the processing mode of different phases twice.P' and Q' are deposited
In a fixed phase difference, foregoing orthogonal calculation still may be implemented, realize the accurate measurement of low voltage signal,
The induced voltage measured be only with the consistent part of the frequency of exciting current signal, and the interference of extraneous different frequency
Magnetic field, especially various wireless signals and power frequency supply signal will be filtered, and induced voltage signal can be substantially improved
Measurement accuracy.
With 50hz, for the sampling rate of 50.505kS/s, measuring principle derives as follows: by the current data point of acquisition
It moves 100 points to be multiplied point by point with electrical voltage point, obtains P'；The current data point of acquisition is moved 300 points and electrical voltage point again by second step
It is point-by-point again to be multiplied, obtain Q'.There is the phase difference of 200 points between the two in this way.As long as this phase difference is in reasonable range
It is interior, can arbitrarily it be arranged.If you need to verify this method reasonability, correctness, by setting out of phase difference and measurement result can be checked
Whether completely the same method is realized.Above-mentioned formula can be deformed into following formula in this example:
According to trigonometric function and poor formula, above formula is unfolded
Q'=UrmsIrmscos(φ+φ200)=UrmsIrmscosφcosφ200-UrmsIrmssinφsinφ200
(3.3)
sinφ200With cos φ200It is constant, there is following formula:
By formula and formula two sides difference square, then sums it up, obtains:
Calibration method described in the present embodiment can accurately obtain the virtual value of induced voltage, utmostly counteract to the greatest extent
External interference signal.Such as this method accurate and effective, then should under out of phase angle measurement result it is consistent.To verify this method,
Different phase angles or even different start-phases are converted in same measurement result, measurement result such as following table 1-1, can
To find out, the calculated result under different phase angles is consistent, and deviation is ± 0.001%, this illustrates this project algorithm
Correctness and validity.
Table 1-1
Embodiment two,
Fig. 5 is a kind of structural schematic diagram of Helmholtz coil constant exchange calibration system based on orthogonality principle.
As shown in figure 5, a kind of Helmholtz coil constant based on orthogonality principle exchanges calibration system, comprising: sine wave
AC signal generating device 6, for generating the sine wave AC signal of different frequency；Power amplifier 2, for by it is described just
String wave AC signal amplifies and is sent to Helmholtz coil 3, and the Helmholtz coil 3 is made to generate AC excitation signal；Number
Word power meter 4, the induced electricity that the small coil 5 under the action of the AC excitation signal, acquiring known circle area generates
Press the U and exciting current I by the Helmholtz coil 3；Induced voltage virtual value computing module 7, based on according to first
Calculate product P', Yi Jigen that rule the induced voltage and the exciting current is calculated induced voltage and exciting current
The induced voltage and the exciting current are calculated according to the second computation rule the product of induced voltage and exciting current
Q', and product P' and product Q' based on induced voltage and exciting current, are calculated using orthogonality principle, obtain induced electricity
It is pressed with valid value Urms；Coil constant computing module 8, for being based on the induced voltage virtual value UrmsWith the exciting current I,
Helmholtz coil constant is calculated.
As shown in fig. 6, the induced voltage virtual value computing module 7, comprising: acquisition submodule 71, for obtaining induction
Voltage curve and magnetizing current curve；Induced voltage data point acquires submodule 72, for acquiring sense from the voltage curve
Answer voltage data point；First movement submodule 73, for the current curve to move right the first numerical value excitation along horizontal axis
Current data point, so that there are first phase differences between current curve and original current curve after mobile；First calculates submodule
Block 74, for being encouraged based on corresponding on the current curve after the induced voltage data point and movement on the voltage curve
Product P' is calculated in magnetoelectricity fluxion strong point, point-by-point be multiplied.Specifically, induced voltage is calculated and encourages according to following formula
The product P' of magnetoelectricity stream, comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+x indicates voltage number on induced voltage curve
Strong point moves right the number after x numerical point, and n is the sum of voltage data point on voltage curve, UiIt is known circle area
Small coil 5 induced voltage, IiIt is by the exciting current of the Helmholtz coil 3, φ is induced voltage virtual value
UrmsWith exciting current IrmsPhase angle.
As shown in fig. 7, the induced voltage virtual value computing module 7, comprising: the acquisition submodule 71, for obtaining
Induced voltage curve and magnetizing current curve；The induced voltage data point acquires submodule 72, is used for from the voltage curve
Upper acquisition induced voltage data point；Second mobile submodule 75, for the current curve to be moved second value point along horizontal axis
A exciting current data point, so that there are second phase between current curve and original current curve after mobile is poor, described the
Difference between two-phase potential difference and the first phase difference is less than or equal to a cycle；Second computational submodule 76 is used for base
Corresponding exciting current data on the current curve after the induced voltage data point and movement on the voltage curve
Product Q' is calculated in point.Specifically, the product Q' of induced voltage and exciting current is calculated according to following formula, wraps
It includes:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+y indicates voltage number on induced voltage curve
Strong point moves right the number after y numerical point, and y-x is less than or equal to a cycle, and n is voltage data on voltage curve
The sum of point, UiIt is the induced voltage of the small coil 5 of known circle area, IiIt is the excitation electricity by the Helmholtz coil 3
Stream, φ is induced voltage virtual value UrmsWith exciting current IrmsPhase angle.
Specifically, induced voltage virtual value is calculated in induced voltage virtual value computing module 7 in accordance with the following methods:
In formula, IrmsFor exciting current virtual value, UrmsFor induced voltage virtual value, φ is between product P' and product Q'
Phase difference, sin φy-xWith cos φy-xIt is constant.
Specifically, exciting current virtual value IrmsCalculation it is as follows:
In formula, j indicates the number of current data point on current curve, and m is the sum of current data point on current curve.
Specifically, Helmholtz coil constant is calculated in coil constant computing module 8 in accordance with the following methods:
In formula: UrmsFor small coil-induced voltage effective value, f is signal source frequency, and NS is circle area, μ known to small coil0
For magnetic constant, khFor Helmholtz coil constant, IrmsTo pass through the current effective value of Helmholtz coil.
The product P' that discovery digital power meter 4 provides in real use is that the every bit on true practical curve is calculated,
And product Q' is really not so, not obtains according to definition node-by-node algorithm, but be calculated by apparent energy and product P',
Therefore orthogonal calculation can not be realized according to the product P' and Q' for directly the instrument being applied to provide.
To realize that the present embodiment can accurately measure voltage effective value, induced electricity is devised in the embodiment of the present invention and is pressed with
Valid value computing module 7, for collecting and recording the data point of 4 experiment curv of digital power meter, it is therefore an objective to data are voluntarily extracted,
Data processing is voluntarily done from principle, realizes the measurement of true Q', and then realizes orthogonal calculation and is accurately incuded
Voltage value.
But another question is also encountered in fact, doing so --- the points that can be sampled by digital power meter 4
It can be 50.505kS/s, 151.515kS/s, 303.03kS/s, the fixed values such as 606.061kS/s, 1212.12kS/s, such as following table
Shown, the points in a period cannot be eliminated just by 4, therefore can not be accurately controlled and be moved 90 degree of phases, to cannot directly press
It is calculated according to the conventional method of active power and reactive power.
Table 1-2
In order to overcome the problems referred above, in the present embodiment, migration current is obtained to the processing mode of different phases twice
P' and Q'.There are a fixed phase differences by P' and Q', and foregoing orthogonal calculation still may be implemented, realize low-voltage
The accurate measurement of signal, that is, the induced voltage measured be only with the consistent part of the frequency of exciting current signal, and it is extraneous
The interference magnetic field of different frequency, especially various wireless signals and power frequency supply signal will be filtered, can be substantially improved
The measurement accuracy of induced voltage signal.
Embodiment three,
Calibration cartridge is exchanged in order to verify the Helmholtz coil constant based on orthogonality principle of proposition of the embodiment of the present invention
It sets, the validity of method and system, using the calibrating installation and quadrature voltage measurement method of the embodiment of the present invention, in different frequencies
The ambient noise of measurement voltage signal under rate, i.e., while giving 3 excitation of Helmholtz coil, by small coil 5 from Helmholtz
Coil 3 removes and far from Helmholtz coil 3, with the induced voltage signal of Orthogonal Method measurement at this time.Measurement result such as following table 1-
The voltage background noise arrived and untreated back shown in 3, in table it can be seen that under selected frequency, after orthogonal calculation
Scape noise is compared to greatly weakening, i.e., most useless interference signals are effectively addressed, orthogonal calculation rear backdrop noise
Influence to voltage measurement is reduced within 0.005%, shows to calibrate Helmholtz using the method that the embodiment of the present invention proposes
When coil 3, ambient noise can be controlled relative to the negligible level of measured signal, while illustrated of the invention real
The measurement method for applying example proposition can be effective anti-interference, improves the accuracy of measurement of induced voltage.
Table 1-3 60Hz is the selected frequency for being used to calibrate Helmholtz coil 3 of the embodiment of the present invention, uses the present invention
The quadrature voltage measurement method that embodiment is established, the ambient noise of multiple measurement voltage signal at 60Hz.6 measurement results
As shown in the table, it can be seen that the voltage background noise arrived under 60Hz after orthogonal calculation is 0.003-0.004mV, not only very
It is weak and be consistent, show the measurement method proposed using the embodiment of the present invention, ambient noise (or interference signal) bring
Uncertainty of measurement component is 0.005%.
Table 1-4
The invention has the following advantages:
1, it using calibration method of the invention, calculates separately and is multiplied based on the induced voltage and the exciting current
Product P' and Q', is calculated using orthogonality principle, obtains induced voltage virtual value Urms.Can effectively it remove in induced voltage
Spurious signal improves the accuracy of measurement to accurately determine the virtual value of induced voltage.
2, calibrating installation of the invention is using arbitrary waveform generator 1, power amplifier 2, Helmholtz coil 3, number
Power meter 4 and small coil 5, the above instrument can be bought from the market, and design is simple, and easy to operate, more acurrate measurement voltage has
Valid value.
It should be understood that above-mentioned specific embodiment of the invention is used only for exemplary illustration or explains the present invention
Principle, but not to limit the present invention.Therefore, it is done without departing from the spirit and scope of the present invention
Any modification, equivalent substitution, improvement and etc. should all be included in the protection scope of the present invention.In addition, right appended by the present invention
It is required that being intended to cover the whole fallen into attached claim scope and boundary or this range and the equivalent form on boundary
Change and modification.
Claims (10)
1. a kind of Helmholtz coil constant based on orthogonality principle exchanges calibration method, which is characterized in that use a kind of calibration
Device, the calibrating installation include: sequentially connected arbitrary waveform generator (1), power amplifier (2), Helmholtz coil
(3) and digital power meter (4)；The power amplifier (2) also connects with the digital power meter (4), Helmholtz's line
Circle (3) includes the concentric circular coil of a pair of of series aiding connection；Small line is placed in the central homogeneity range of the Helmholtz coil (3)
It encloses (5)；
The calibration method includes:
The sine wave AC signal of different frequency is generated using arbitrary waveform generator (1)；
The sine wave AC signal is amplified and is sent to the Helmholtz coil (3) by power amplifier (2), makes the last of the twelve Earthly Branches
Mu Huozi coil (3) generates AC excitation signal；
Under the action of the AC excitation signal, digital power meter (4) acquires the induced electricity of the small coil (5) of known circle area
Pressure and the exciting current for passing through the Helmholtz coil (3)；
Induced voltage and exciting current are calculated to the induced voltage and the exciting current according to the first computation rule
Product P', and induced voltage and excitation are calculated to the induced voltage and the exciting current according to the second computation rule
The product Q' of electric current；
Product P' and product Q' based on induced voltage and exciting current, are calculated using orthogonality principle, obtain induced voltage
Virtual value Urms；
Based on the induced voltage virtual value UrmsWith exciting current virtual value Irms, Helmholtz coil constant is calculated.
2. a kind of Helmholtz coil constant according to claim 1 exchanges calibration method, which is characterized in that the basis
First computation rule the induced voltage and the exciting current is calculated the product P' of induced voltage and exciting current, packet
It includes:
Induced voltage curve and magnetizing current curve are obtained using digital power meter (4)；
Induced voltage data point is acquired from the voltage curve；
The current curve is moved right the first numerical value exciting current data point along horizontal axis so that after mobile current curve with
There are first phase differences between original current curve；
Based on corresponding exciting current on the current curve after the induced voltage data point and movement on the voltage curve
Product P' is calculated in data point, point-by-point be multiplied.
3. a kind of Helmholtz coil constant according to claim 2 exchanges calibration method, which is characterized in that based on described
Corresponding exciting current data point on the current curve after induced voltage data point and movement on voltage curve, point-by-point phase
Multiply and product P' be calculated, comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+x indicates voltage data point on induced voltage curve
The number to move right after x numerical point, n are the sum of voltage data point on voltage curve, UiIt is the small of known circle area
The induced voltage of coil (5), IiIt is by the exciting current of the Helmholtz coil (3), φ is induced voltage virtual value Urms
With exciting current IrmsPhase angle.
4. a kind of Helmholtz coil constant according to claim 2 exchanges calibration method, which is characterized in that the basis
Second computation rule the induced voltage and the exciting current is calculated the product Q' of induced voltage and exciting current, packet
It includes:
Induced voltage curve and magnetizing current curve are obtained using digital power meter (4)；
Induced voltage data point is acquired from the voltage curve；
The current curve is moved into second value point exciting current data point along horizontal axis, so that current curve and original after mobile
It is poor that there are second phase between the current curve of beginning, the difference between second phase difference and the first phase difference be less than or
Equal to a cycle；
Based on corresponding exciting current on the current curve after the induced voltage data point and movement on the voltage curve
Product Q' is calculated in data point, point-by-point be multiplied.
5. a kind of Helmholtz coil constant as claimed in claim 4 exchanges calibration method, which is characterized in that be based on the voltage
Corresponding exciting current data point on the current curve after induced voltage data point and movement on curve, the point-by-point meter that is multiplied
Calculation obtains product Q', comprising:
Wherein, i indicates the number of voltage data point on induced voltage curve, and i+y indicates voltage data point on induced voltage curve
The number to move right after y numerical point, y-x are less than or equal to a cycle, and n is the total of voltage data point on voltage curve
Number, UiIt is the induced voltage of the small coil (5) of known circle area, IiBe by the exciting current of the Helmholtz coil (3),
φ is induced voltage virtual value UrmsWith exciting current IrmsPhase angle.
6. a kind of Helmholtz coil constant according to claim 1 exchanges calibration method, which is characterized in that based on induction
The product P' and product Q' of voltage and exciting current, are calculated using orthogonality principle, obtain induced voltage virtual value Urms, tool
Body is calculated in accordance with the following methods:
In formula, IrmsFor exciting current virtual value, UrmsFor induced voltage virtual value, phase of the φ between product P' and product Q'
Difference, sin φy-xWith cos φy-xIt is constant.
7. a kind of Helmholtz coil constant according to claim 6 exchanges calibration method, which is characterized in that the excitation
Current effective value IrmsCalculation it is as follows:
In formula, j indicates the number of current data point on current curve, and m is the sum of current data point on current curve.
8. a kind of Helmholtz coil constant according to claim 1 exchanges calibration method, which is characterized in that described to be based on
The induced voltage virtual value UrmsWith the exciting current I, Helmholtz coil constant is calculated, specifically according to lower section
Method is calculated:
In formula: UrmsFor small coil-induced voltage effective value, f is signal source frequency, and NS is circle area, μ known to small coil0For magnetism
Constant, khFor Helmholtz coil constant, IrmsTo pass through the current effective value of Helmholtz coil.
9. a kind of Helmholtz coil constant based on orthogonality principle exchanges calibration system characterized by comprising
Sine wave AC signal generation apparatus (6), for generating the sine wave AC signal of different frequency；
Power amplifier (2) makes described for amplifying and being sent to Helmholtz coil (3) the sine wave AC signal
Helmholtz coil (3) generates AC excitation signal；
Digital power meter (4), the small coil (5) under the action of the AC excitation signal, acquiring known circle area produce
Raw induced voltage and the exciting current by the Helmholtz coil (3)；
Induced voltage virtual value computing module (7), for electric to the induced voltage and the excitation according to the first computation rule
Stream calculation obtains the product P' of induced voltage and exciting current, and according to the second computation rule to the induced voltage and described
Exciting current is calculated the product Q' of induced voltage and exciting current, and the product P' based on induced voltage and exciting current and
Product Q', is calculated using orthogonality principle, obtains induced voltage virtual value Urms；
Coil constant computing module (8), for being based on the induced voltage virtual value UrmsWith exciting current virtual value Irms, calculate
Obtain Helmholtz coil constant.
10. a kind of Helmholtz coil constant according to claim 9 exchanges calibration system, which is characterized in that the sense
Answer voltage effective value computing module (7), comprising:
Acquisition submodule (71), for obtaining induced voltage curve and magnetizing current curve；
Induced voltage data point acquires submodule (72), for acquiring induced voltage data point from the voltage curve；
First movement submodule (73), for the current curve to move right the first numerical value exciting current data along horizontal axis
Point, so that there are first phase differences between current curve and original current curve after mobile；
First computational submodule (74), for based on the electricity after the induced voltage data point and movement on the voltage curve
Product P' is calculated in corresponding exciting current data point on flow curve, point-by-point be multiplied.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811616067.2A CN109839610B (en) | 2018-12-27 | 2018-12-27 | Helmholtz coil constant alternating current calibration system and method based on orthogonality principle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811616067.2A CN109839610B (en) | 2018-12-27 | 2018-12-27 | Helmholtz coil constant alternating current calibration system and method based on orthogonality principle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109839610A true CN109839610A (en) | 2019-06-04 |
| CN109839610B CN109839610B (en) | 2021-02-12 |
Family
ID=66883411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811616067.2A Active CN109839610B (en) | 2018-12-27 | 2018-12-27 | Helmholtz coil constant alternating current calibration system and method based on orthogonality principle |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109839610B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030828A (en) * | 2021-03-25 | 2021-06-25 | 河南省计量科学研究院 | Alternating magnetometer verification system and method |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1132470A (en) * | 1993-10-06 | 1996-10-02 | 巴依奥桑斯股份有限公司 | Magnetic determination of position and orientation |
| US6750644B1 (en) * | 2000-09-06 | 2004-06-15 | General Electric Company | Magnetic field sensor and method for calibrating the same |
| JP2005084022A (en) * | 2003-09-11 | 2005-03-31 | Neomax Co Ltd | Magnetic field generator for sensor testing and sensor inspection device |
| US7719261B2 (en) * | 2005-11-28 | 2010-05-18 | Hillcrest Laboratories, Inc. | Methods and systems for calibrating a sensor using a vector field |
| CN202031580U (en) * | 2011-04-02 | 2011-11-09 | 北京工业大学 | Active magnetic field calibrator with MWD (measurement while drilling) directional probe |
| WO2016022192A1 (en) * | 2014-08-08 | 2016-02-11 | Halliburton Energy Services, Inc. | Calibration of sensitivity and axial orthogonality for magnetometers |
| WO2016128353A1 (en) * | 2015-02-09 | 2016-08-18 | Pepric Nv | System and method for determining a quantity of magnetic particles |
| CN206209086U (en) * | 2016-09-29 | 2017-05-31 | 江苏多维科技有限公司 | A kind of orthogonal calibration jig of 3D Magnetic Sensors |
| CN206515456U (en) * | 2017-01-17 | 2017-09-22 | 江苏省计量科学研究院 | A kind of calibrating installation of magnetic field intensity tester |
| CN206684286U (en) * | 2017-04-06 | 2017-11-28 | 深圳市柯雷科技开发有限公司 | A kind of alternation power frequency magnetic field calibrating installation |
| CN108535666A (en) * | 2018-03-28 | 2018-09-14 | 深圳市启荣科技发展有限责任公司 | Any direction motion vector uniform magnetic field generating means and control system |
-
2018
- 2018-12-27 CN CN201811616067.2A patent/CN109839610B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1132470A (en) * | 1993-10-06 | 1996-10-02 | 巴依奥桑斯股份有限公司 | Magnetic determination of position and orientation |
| US6750644B1 (en) * | 2000-09-06 | 2004-06-15 | General Electric Company | Magnetic field sensor and method for calibrating the same |
| JP2005084022A (en) * | 2003-09-11 | 2005-03-31 | Neomax Co Ltd | Magnetic field generator for sensor testing and sensor inspection device |
| US7719261B2 (en) * | 2005-11-28 | 2010-05-18 | Hillcrest Laboratories, Inc. | Methods and systems for calibrating a sensor using a vector field |
| CN202031580U (en) * | 2011-04-02 | 2011-11-09 | 北京工业大学 | Active magnetic field calibrator with MWD (measurement while drilling) directional probe |
| WO2016022192A1 (en) * | 2014-08-08 | 2016-02-11 | Halliburton Energy Services, Inc. | Calibration of sensitivity and axial orthogonality for magnetometers |
| WO2016128353A1 (en) * | 2015-02-09 | 2016-08-18 | Pepric Nv | System and method for determining a quantity of magnetic particles |
| CN206209086U (en) * | 2016-09-29 | 2017-05-31 | 江苏多维科技有限公司 | A kind of orthogonal calibration jig of 3D Magnetic Sensors |
| CN206515456U (en) * | 2017-01-17 | 2017-09-22 | 江苏省计量科学研究院 | A kind of calibrating installation of magnetic field intensity tester |
| CN206684286U (en) * | 2017-04-06 | 2017-11-28 | 深圳市柯雷科技开发有限公司 | A kind of alternation power frequency magnetic field calibrating installation |
| CN108535666A (en) * | 2018-03-28 | 2018-09-14 | 深圳市启荣科技发展有限责任公司 | Any direction motion vector uniform magnetic field generating means and control system |
Non-Patent Citations (2)
| Title |
|---|
| EDWIN L. BRONAUGH: "Helmholtz coils for calibration of probes and sensors: limits of magnetic field accuracy and uniformity", 《PROCEEDINGS OF INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY》 * |
| 李颂扬 等: "一维亥姆霍兹线圈校准方法的研究", 《轻工标准与质量》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030828A (en) * | 2021-03-25 | 2021-06-25 | 河南省计量科学研究院 | Alternating magnetometer verification system and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109839610B (en) | 2021-02-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Dong et al. | A high-precision frequency measurement algorithm for FID signal of proton magnetometer | |
| Tan et al. | A frequency measurement method based on optimal multi-average for increasing proton magnetometer measurement precision | |
| CN108717168A (en) | A kind of Scalar Magnetic Field gradient measuring device and method based on the modulation of light field amplitude | |
| CN110865238B (en) | Alternating current resistance measurement method and device based on quasi-harmonic model sampling algorithm | |
| Liu et al. | Construction of an Overhauser magnetic gradiometer and the applications in geomagnetic observation and ferromagnetic target localization | |
| Tan et al. | Nonlinear compensation method based on data for increasing absolute measurement precision of FID signal | |
| van den Brom et al. | Sampling Current Ratio Measurement System for Calibration of Current Transducers up to 10 kA With $5\cdot 10^{\mathrm {-6}} $ Uncertainty | |
| Mahavarkar et al. | The low cost proton precession magnetometer developed at the Indian institute of geomagnetism | |
| CN109839610A (en) | Helmholtz coil constant exchange calibration system and method based on orthogonality principle | |
| CN109394214A (en) | A kind of biological impedance apparatus and method based on isolation exciting current phase locking technique | |
| Reutov et al. | Possibilities for the selection of magnetic field transducers for nondestructive testing. | |
| Li et al. | A compensation method to measure the mutual inductance at low frequency | |
| Ishii et al. | Improvement of formula and uncertainty of the reference magnetic field for AC magnetometer calibration | |
| Shi et al. | Self-calibration of the phase angle errors of RVDs at frequencies up to 100 kHz | |
| Tan et al. | A frequency measurement method using rising-falling edge of square wave for increasing proton magnetometer precision | |
| Tan et al. | A linearized model of FID signal for increasing proton magnetometer precision | |
| Ripka et al. | A 3-phase current transducer based on microfluxgate sensors | |
| CN112284377A (en) | Geomagnetic field measurement system and method applied to aircraft | |
| Liu et al. | A high precision proton magnetometer based on a multi-channel frequency measurement | |
| RU2420751C1 (en) | Calibration device for measuring devices of quality parametres of electric energy at distorted signals | |
| CN101819234B (en) | Device and method for measuring AC mutual induction with compensation method | |
| Zhang et al. | Study on methods of sensitivity evaluation of JPM-4 proton magnetometer | |
| CN114137448B (en) | Single-beam non-modulation type triaxial magnetic field measuring device and method | |
| Xiaojuan et al. | Comparison of three kinds of compensation algorithms based on magnetic sensors | |
| RU2252422C1 (en) | Method and device for measuring electric current |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |