CN109342977B - Method and system for offsetting magnetic field alternating current interference - Google Patents
Method and system for offsetting magnetic field alternating current interference Download PDFInfo
- Publication number
- CN109342977B CN109342977B CN201811136783.0A CN201811136783A CN109342977B CN 109342977 B CN109342977 B CN 109342977B CN 201811136783 A CN201811136783 A CN 201811136783A CN 109342977 B CN109342977 B CN 109342977B
- Authority
- CN
- China
- Prior art keywords
- magnetic field
- signal
- output value
- signal output
- alternating current
- 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.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/0023—Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration
- G01R33/0029—Treating the measured signals, e.g. removing offset or noise
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
The invention provides a method for counteracting alternating current interference of a magnetic field, which measures the current magnetic field through a fluxgate magnetic sensor and acquires a first signal; measuring the alternating current component of the current magnetic field through an inductive magnetic sensor, and acquiring a second signal; acquiring a first signal and a second signal through a signal acquisition device, and transmitting an acquired first signal output value and an acquired second signal output value to a computer device; and the computer device calculates the direct current component in the current magnetic field environment according to the acquired first signal output value and the acquired second signal output value. On the premise of not limiting the bandwidth and not prolonging the response time, the invention utilizes the induction type magnetic sensor to measure the characteristics of alternating current signals only, and cancels the alternating current signals, especially low-frequency signals in the magnetic field through calculation to obtain relatively stable direct current components in the magnetic field.
Description
Technical Field
The invention relates to the technical field of magnetic field interference cancellation, in particular to a method and a system for canceling magnetic field alternating current interference.
Background
In the daily environment, the magnetic field state is usually a constant magnetic field and a complex alternating magnetic field superposed on the constant magnetic field. The measurement of the geomagnetic field is mainly carried out by using a fluxgate sensor, according to the fluxgate principle, the output value of the fluxgate sensor is in a linear relation with the magnitude of the environmental magnetic field, and the output value of the fluxgate sensor comprises a direct current component and an alternating current component in the measured magnetic field.
In some cases, it is necessary to measure the dc component of the ambient magnetic field, such as measuring whether an object is magnetic or not in a non-shielding environment, or the magnitude of the magnetic field generated by the object. The existing approach is to limit the bandwidth of the fluxgate sensor to filter out the low frequency magnetic field by low pass filtering.
However, in an analog circuit, a low-frequency magnetic field cannot be filtered out by a low-pass filtering method, and in a digital circuit, although the cut-off frequency of the low-pass filtering can be very low, the limitation on the bandwidth greatly increases the response time, and timely measurement cannot be achieved.
Disclosure of Invention
The invention provides a method and a system for offsetting magnetic field alternating current interference, which aim to solve the problem that the prior art cannot well offset the magnetic field alternating current interference.
The first aspect of the present invention provides a method for canceling magnetic field alternating current interference, including:
measuring a current magnetic field through a fluxgate magnetic sensor, and acquiring a first signal;
measuring the alternating current component of the current magnetic field through an inductive magnetic sensor, and acquiring a second signal;
acquiring a first signal and a second signal through a signal acquisition device, and transmitting an acquired first signal output value and an acquired second signal output value to a computer device;
and the computer device calculates the direct current component in the current magnetic field environment according to the acquired first signal output value and the acquired second signal output value.
Further, the first signal is all signals of the current magnetic field, and the second signal is an alternating current signal of the current magnetic field.
Further, the obtaining, by the computer device, the dc component of the current magnetic field according to the obtained first signal output value and the second signal output value includes:
acquiring the actual size of the current magnetic field according to the first signal output value;
acquiring an alternating current component of the current magnetic field according to the second signal output value;
and (4) subtracting the actual size of the current magnetic field from the alternating current component to obtain the direct current component of the current magnetic field.
Further, acquiring the alternating current component of the current magnetic field according to the second signal output value includes:
obtaining the impact response of the inductive magnetic sensor based on the frequency domain transfer function of the inductive magnetic sensor;
and performing deconvolution operation on the second signal output value and the impact response to obtain the alternating current component of the current magnetic field.
Further, the deconvoluting operation of the second signal output value and the impulse response to obtain the alternating current component of the current magnetic field includes:
representing the impulse response as a finite point
Wherein the number of the points is m + 1;
the input quantity sequence of the inductive magnetic sensor is
Wherein x represents the input value of each point, k represents the acquired time, and N represents the number of points selected at the k time;
obtaining an output voltage value of the inductive magnetic sensor as
And performing deconvolution calculation on the obtained discrete output voltage value and the impulse response by adopting an iterative algorithm to obtain an alternating current component in the current magnetic field environment.
Further, the deconvolution calculation is performed on the obtained discrete output voltage value and the impulse response by using an iterative algorithm to obtain the alternating current component in the current magnetic field environment, and the method includes:
outputting an estimated vector with respect to input X at a certain time
Estimating vectors
Performing corresponding multiplication operation with the impact response sequence to obtain
Subtracting the estimated vector from the output value at the next time to obtain the final valueObtaining an error term
According to the formula
To obtainWherein
The artificial control coefficient can be obtained according to the experience of the actual situation,the input X sequence is subjected to error correction;
error corrected input X sequence
Performing corresponding multiplication operation with the impact response sequence to obtain
Completing one iteration;
repeating the steps D1-D5 to obtain the error estimation vector which meets the precision requirement and is related to X
Wherein k represents the number of iterations, which can be obtained according to the required degree of accuracy;
i.e. the input value of the system at the next moment, i.e. the alternating current component of the magnetic field in the environment.
The invention provides a magnetic field alternating current interference cancellation system, which comprises a fluxgate magnetic sensor, an inductive magnetic sensor, a signal acquisition device and a computer device, wherein the fluxgate magnetic sensor is arranged on the computer device;
the fluxgate magnetic sensor is connected with the signal acquisition device and used for measuring a current magnetic field and acquiring a first signal;
the induction type magnetic sensor is connected with the signal acquisition device and is used for measuring the alternating current component of the current magnetic field and acquiring a second signal;
the signal acquisition device is connected with the computer device and is used for acquiring a first signal and a second signal and transmitting a first signal output value and a second signal output value to the computer device;
and the computer device is used for calculating the direct current component in the current magnetic field environment according to the first signal output value and the second signal output value.
Further, the computer device obtains the actual size of the current magnetic field according to the first signal output value, and obtains the alternating current component of the current magnetic field according to the second signal output value; and (4) subtracting the actual size of the current magnetic field from the alternating current component to obtain the direct current component of the current magnetic field.
Further, the obtaining the ac component of the current magnetic field according to the second signal output value includes:
obtaining the impact response of the inductive magnetic sensor based on the frequency domain transfer function of the inductive magnetic sensor;
and performing deconvolution operation on the second signal output value and the impact response to obtain the alternating current component of the current magnetic field.
Further, the fluxgate magnetic sensor is kept at a distance from the inductive magnetic sensor.
The technical effects of the method and the system for counteracting the magnetic field interference provided by the invention are as follows:
on the premise of not limiting the bandwidth and not prolonging the response time, the invention utilizes the induction type magnetic sensor to measure the characteristics of alternating current signals only, and cancels the alternating current signals, especially low-frequency signals in the magnetic field through calculation to obtain relatively stable direct current components in the magnetic field.
Drawings
FIG. 1 is a flow chart illustrating a magnetic field AC interference cancellation method according to an exemplary embodiment of the present invention;
fig. 2 is a schematic structural diagram of a magnetic field ac interference cancellation system according to another exemplary embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a flowchart illustrating a magnetic field ac interference cancellation method according to an exemplary embodiment of the present invention.
As shown in fig. 1, the method for canceling magnetic field ac interference provided by this embodiment includes:
step 101, measuring a current magnetic field through a fluxgate magnetic sensor, and acquiring a first signal.
In the daily environment, the magnetic field state is usually a constant alternating current magnetic field with complex magnetic field superposition, the measurement of the geomagnetic field is mainly carried out by applying a fluxgate sensor, according to the fluxgate principle, the output value of the sensor is in a linear relation with the magnitude of the environmental magnetic field, and the output value of the sensor comprises the value of a direct current component and the value of an alternating current component in the measured magnetic field, so that the output value of the sensor can be obtained by obtaining a first signal of the fluxgate magnetic sensor, namely all signals of the current magnetic field, including the direct current signal and the alternating current signal, and then the actual magnitude of the magnetic field can be obtained according to the linear relation between the output value of the sensor and the environmental magnetic field.
And 102, measuring the alternating current component of the current magnetic field through the inductive magnetic sensor, and acquiring a second signal.
Since the inductive magnetic sensor has a characteristic of measuring only an ac signal, the inductive magnetic sensor can be used to acquire the ac signal of the current magnetic field, i.e., the second signal. After the signal is subjected to inductive magnetic sensing, the output value of the signal is equal to the convolution of the alternating current signal and the system impact response, so that the output value of the inductive magnetic sensor and the impact response can be subjected to deconvolution operation, and the input of the inductive magnetic sensor, namely the value of the alternating current component in the environmental magnetic field can be obtained.
It should be noted that, step 101 and step 102 have no logical order relationship, and may be executed first 101, or may be executed first 102, or may be executed simultaneously with step 101 and step 102, which is not limited in this embodiment.
And 103, acquiring the first signal and the second signal through the signal acquisition device, and transmitting the acquired first signal output value and the acquired second signal output value to the computer device.
In this embodiment, a signal acquisition device, such as a signal acquisition card, may be provided to acquire the first signal and the second signal, and transmit the digitized first signal output value and the digitized second signal output value to the computer device for calculating the current dc component of the magnetic field.
And 104, calculating the direct current component of the current magnetic field by the computer device according to the acquired first signal output value and the acquired second signal output value.
Specifically, the dc component of the current magnetic field may be calculated by:
and 1041, acquiring the actual size of the current magnetic field according to the first signal output value.
For a specific obtaining process, refer to step 101, and details are not described herein.
And 1042, acquiring the alternating current component of the current magnetic field according to the second signal output value.
And 1043, subtracting the actual magnitude of the current magnetic field from the alternating current component to obtain a direct current component of the current magnetic field.
Wherein, step 1041 and step 1042 have no logical sequence relationship, and may be executed first 1041, or executed first 1042, or executed both 1041 and 1042, which is not limited in this embodiment.
Of course, the computer device can also display the calculation result of the direct current component at the same time, so that the direct current component of the magnetic field can be displayed in real time.
In the embodiment, the fluxgate magnetic sensor and the inductive magnetic sensor are used for respectively acquiring the first signal and the second signal, the acquisition device is used for acquiring the first signal and the second signal, and the acquired signals are transmitted to the computer device for calculating and displaying the direct current component in the current magnetic field environment. According to the embodiment, on the premise of not limiting the bandwidth and not prolonging the response time, the inductive magnetic sensor can only measure the characteristics of the alternating current signal, and the alternating current signal, especially the low-frequency signal, in the magnetic field is counteracted to obtain the relatively stable direct current component in the magnetic field.
Further, in the above embodiment, for step 1042, acquiring the alternating current component of the current magnetic field according to the second signal output value may specifically include:
10421, obtaining an impulse response of the inductive magnetic sensor based on the frequency domain transfer function of the inductive magnetic sensor.
For the inductive magnetic sensor, according to the equivalent principle of the sensor and in combination with circuit analysis, the frequency domain transfer function of the inductive magnetic sensor is as follows:
where j represents an imaginary unit, ω represents an angular frequency, N represents the number of coil turns, ScDenotes the cross-sectional area, μ, of the coreaEffective permeability of the core, RfFor feedback resistance, G is the amplification factor of the amplification circuit, C is the capacitance between the coils, and LsIs the inductance of the coil, M is the mutual inductance between the induction coil and the feedback coil, and R is the coil resistance.
According to the actually used inductive magnetic sensor, the parameters are known, the sensitivity of the selected inductive magnetic sensor can be obtained by substituting the known parameters, and the impact response of the system can be obtained based on matlab simulation calculation.
10422, deconvoluting the second signal output value with the impulse response to obtain the alternating current component of the current magnetic field.
It is known that a signal passes through a system whose output value is equal to the convolution of the signal with the impulse response of the system. Therefore, the output value of the inductive magnetic sensor and the impact response thereof can be subjected to deconvolution operation, and the input of the inductive magnetic sensor, that is, the value of the alternating current component in the ambient magnetic field can be obtained.
For the deconvolution operation, since the data is huge and the implementation effect cannot be guaranteed, the present embodiment selects an iterative algorithm to perform the deconvolution operation, and specifically, the process may include the following steps:
A. representing the impulse response as a finite point
Wherein the number of the points is m + 1;
B. the input quantity sequence of the inductive magnetic sensor isWherein, x represents the input value of each point, k represents the acquired time, and N represents the number of points selected at the k time;
C. obtaining a voltage value output by the inductive magnetic sensor as
D. And performing deconvolution calculation on the obtained discrete output voltage value and the impulse response by adopting an iterative algorithm to obtain an alternating current component in the current magnetic field environment.
Further, deconvoluting the obtained discrete output voltage value and the impulse response by using an iterative algorithm to obtain an alternating current component in the current magnetic field environment may include:
d1, outputting an estimated vector about input X at a certain time
D2, estimation vector
Performing corresponding multiplication operation with the impact response sequence to obtain
D3, subtracting the estimated vector from the output value at the next time to obtain an error term
D4, according to the formula
To obtain
Wherein
The artificial control coefficient can be obtained according to the experience of the actual situation,
the input X sequence is subjected to error correction;
d5 error corrected input X sequence
Performing corresponding multiplication operation with the impact response sequence to obtainCompleting one iteration;
d6, repeating the steps D1-D5 to obtain the error estimation vector which meets the precision requirement and is related to X
Wherein k represents the number of iterations, which can be obtained according to the required degree of accuracy;
i.e. the input value of the system at the next moment, i.e. the alternating current component of the magnetic field in the environment.
It should be noted that the first signal output value and the second signal output value are voltage values of the magnetic field, the first signal output value may be divided by a coefficient to obtain a magnetic field value, and the second signal output value may be converted into the magnetic field value after being calculated, so as to obtain an alternating current component in the current magnetic field.
Through the iterative algorithm, the input value of the sensor at the next moment can be iteratively calculated according to the output value of the inductive magnetic sensor at the previous moment, and then the input value of the sensor at the next moment is calculated according to the output true value of the sensor at the next moment and the result of the previous iteration, and the calculation is sequentially carried out, so that the input value of the inductive magnetic sensor, namely the alternating current component in the environmental magnetic field, can be iteratively calculated according to the output result of the inductive magnetic sensor and the impulse response of the inductive magnetic sensor; because the computer has high calculation speed, the calculation time can be ignored, the system has no calculation delay, and the calculation result measured by the fluxgate and the iterative calculation result of the induction type magnetic sensor can be subtracted in a time domain to obtain the direct current component in the environmental magnetic field in real time.
As shown in fig. 2, the present application further provides a magnetic field interference cancellation system, which includes a fluxgate magnetic sensor, an inductive magnetic sensor, a signal acquisition device, and a computer device;
the fluxgate magnetic sensor is connected with the signal acquisition device and used for measuring a current magnetic field and acquiring a first signal;
the induction type magnetic sensor is connected with the signal acquisition device and is used for measuring the alternating current component of the current magnetic field and acquiring a second signal;
the signal acquisition device is connected with the computer device and is used for acquiring a first signal and a second signal and transmitting a first signal output value and a second signal output value to the computer device;
and the computer device is used for calculating the direct current component in the current magnetic field environment according to the first signal output value and the second signal output value.
In practical application, the fluxgate magnetic sensor and the inductive magnetic sensor can be placed at certain positions in a static way, and the two magnetic sensors keep a certain distance, so that the two sensors are ensured not to influence each other, and the distance can be 1m for example; the acquisition device acquires signals of the fluxgate magnetic sensor and the inductive magnetic sensor, and correspondingly calculates and displays the direct current component in the current magnetic field environment in the computer device.
The specific principle and implementation of the magnetic field interference cancellation apparatus provided in this embodiment are similar to those of the embodiment shown in fig. 1, and are not described herein again.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (5)
1. A method for canceling magnetic field ac interference, comprising:
measuring a current magnetic field through a fluxgate magnetic sensor, and acquiring a first signal;
measuring the alternating current component of the current magnetic field through an inductive magnetic sensor, and acquiring a second signal;
acquiring a first signal and a second signal through a signal acquisition device, and transmitting an acquired first signal output value and an acquired second signal output value to a computer device;
the computer device calculates the direct current component in the current magnetic field environment according to the acquired first signal output value and the acquired second signal output value;
the first signal is all signals of the current magnetic field, and the second signal is an alternating current signal of the current magnetic field;
the computer device obtains the direct current component of the current magnetic field according to the obtained first signal output value and the second signal output value, and the method comprises the following steps:
acquiring the actual size of the current magnetic field according to the first signal output value;
acquiring an alternating current component of the current magnetic field according to the second signal output value;
the actual size of the current magnetic field is subtracted from the alternating current component to obtain the direct current component of the current magnetic field;
acquiring the alternating current component of the current magnetic field according to the second signal output value, wherein the method comprises the following steps:
obtaining the impact response of the inductive magnetic sensor based on the frequency domain transfer function of the inductive magnetic sensor;
and performing deconvolution operation on the second signal output value and the impact response to obtain the alternating current component of the current magnetic field.
2. The method of claim 1, wherein deconvolving the second signal output value with the impulse response to obtain the alternating current component of the current magnetic field comprises:
representing the impulse response as a finite point
Wherein the number of the points is m + 1;
the input quantity sequence of the inductive magnetic sensor isWherein x represents the input value of each point, k represents the acquired time, and N represents the number of points selected at the k time;
obtaining an output voltage value of the inductive magnetic sensor as
And performing deconvolution calculation on the obtained discrete output voltage value and the impulse response by adopting an iterative algorithm to obtain an alternating current component in the current magnetic field environment.
3. The method of claim 2, wherein the deconvolving the obtained discrete output voltage values with the impulse response using an iterative algorithm to obtain the alternating current component in the current magnetic field environment comprises:
outputting an estimated vector with respect to input X at a certain time
Estimating vectors
Performing corresponding multiplication operation with the impact response sequence to obtain
Subtracting the estimated vector from the output value at the next time to obtain an error term
According to the formula
To obtain
Wherein
The artificial control coefficient can be obtained according to the experience of the actual situation,
the input X sequence is subjected to error correction;
error corrected input X sequencePerforming corresponding multiplication operation with the impact response sequence to obtain
Completing one iteration;
repeating the steps D1-D5 to obtain the error estimation vector which meets the precision requirement and is related to X
Wherein k represents the number of iterations, which can be obtained according to the required degree of accuracy;
i.e. the input value of the system at the next moment, i.e. the alternating current component of the magnetic field in the environment.
4. A magnetic field alternating current interference cancellation system is characterized by comprising a fluxgate magnetic sensor, an induction type magnetic sensor, a signal acquisition device and a computer device;
the fluxgate magnetic sensor is connected with the signal acquisition device and used for measuring a current magnetic field and acquiring a first signal;
the induction type magnetic sensor is connected with the signal acquisition device and is used for measuring the alternating current component of the current magnetic field and acquiring a second signal;
the signal acquisition device is connected with the computer device and is used for acquiring a first signal and a second signal and transmitting a first signal output value and a second signal output value to the computer device;
the computer device is used for calculating the direct current component in the current magnetic field environment according to the first signal output value and the second signal output value;
the computer device obtains the actual size of the current magnetic field according to the first signal output value and obtains the alternating current component of the current magnetic field according to the second signal output value; the actual size of the current magnetic field is subtracted from the alternating current component to obtain the direct current component of the current magnetic field;
the obtaining of the ac component of the current magnetic field according to the second signal output value includes:
obtaining the impact response of the inductive magnetic sensor based on the frequency domain transfer function of the inductive magnetic sensor;
and performing deconvolution operation on the second signal output value and the impact response to obtain the alternating current component of the current magnetic field.
5. The system of claim 4, wherein the fluxgate magnetic sensor is spaced apart from the inductive magnetic sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811136783.0A CN109342977B (en) | 2018-09-28 | 2018-09-28 | Method and system for offsetting magnetic field alternating current interference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811136783.0A CN109342977B (en) | 2018-09-28 | 2018-09-28 | Method and system for offsetting magnetic field alternating current interference |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109342977A CN109342977A (en) | 2019-02-15 |
| CN109342977B true CN109342977B (en) | 2020-02-04 |
Family
ID=65307098
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811136783.0A Active CN109342977B (en) | 2018-09-28 | 2018-09-28 | Method and system for offsetting magnetic field alternating current interference |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109342977B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1308721A1 (en) * | 2001-11-02 | 2003-05-07 | Corus Technology BV | Device and method for detecting magnetic properties of a metal object |
| CN202393896U (en) * | 2011-12-29 | 2012-08-22 | 中天启明石油技术有限公司 | Underground oscillating magnetic field measuring device |
| CN103424780A (en) * | 2013-08-27 | 2013-12-04 | 中国航空无线电电子研究所 | Aircraft magnetic environment compensation method based on induction coils |
| CN104345204A (en) * | 2013-08-07 | 2015-02-11 | 德州仪器德国股份有限公司 | Hybrid closed-loop/open-loop magnetic current sensor |
| CN106093548A (en) * | 2016-08-04 | 2016-11-09 | 中国船舶重工集团公司第七〇九研究所 | A kind of contactless high accuracy shaft current measurement apparatus |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102590328B (en) * | 2012-02-14 | 2015-01-21 | 厦门大学 | Permanent magnetic and alternating current direct current composite magnetic flux leakage detecting method |
-
2018
- 2018-09-28 CN CN201811136783.0A patent/CN109342977B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1308721A1 (en) * | 2001-11-02 | 2003-05-07 | Corus Technology BV | Device and method for detecting magnetic properties of a metal object |
| CN202393896U (en) * | 2011-12-29 | 2012-08-22 | 中天启明石油技术有限公司 | Underground oscillating magnetic field measuring device |
| CN104345204A (en) * | 2013-08-07 | 2015-02-11 | 德州仪器德国股份有限公司 | Hybrid closed-loop/open-loop magnetic current sensor |
| CN103424780A (en) * | 2013-08-27 | 2013-12-04 | 中国航空无线电电子研究所 | Aircraft magnetic environment compensation method based on induction coils |
| CN106093548A (en) * | 2016-08-04 | 2016-11-09 | 中国船舶重工集团公司第七〇九研究所 | A kind of contactless high accuracy shaft current measurement apparatus |
Non-Patent Citations (1)
| Title |
|---|
| 基于磁通门传感器的高精度弱磁场便携检测系统;赖正喜;《中国优秀硕士学位论文全文数据库 信息科技辑》;20150715(第07期);第I140-204页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109342977A (en) | 2019-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| IL169150A (en) | Method and device for magnetic measurement of the position and orientation of a mobile object relative to a fixed structure | |
| KR20110132527A (en) | Method and device for calibrating a three-axis magnetic field sensor | |
| CN105277995B (en) | The interference compensation method and device of geomagnetic sensor | |
| JP2010501873A (en) | Measuring method and apparatus for potentiometric measuring probe | |
| KR20120059956A (en) | An apparatus for adaptively compensating position error of resolver | |
| CN110907827B (en) | Motor transient distortion measuring method and system | |
| CN110865238B (en) | Alternating current resistance measurement method and device based on quasi-harmonic model sampling algorithm | |
| JP2003531350A (en) | Magnetic device for determining orientation unaffected by induced disturbances and corresponding method | |
| KR20120082607A (en) | Temperature compensation method of sensor, and sensor including temperature compensating function | |
| JP2012522210A (en) | Apparatus and method for ferromagnetic object detector | |
| CN109342977B (en) | Method and system for offsetting magnetic field alternating current interference | |
| CN112088289B (en) | Measuring method and electronic measuring unit using inductive proximity sensor connected to cable | |
| RU2447452C1 (en) | Bridge circuit for measuring parameters of two-terminal devices | |
| CN112130003B (en) | Device and method for removing electromagnetic interference signals in same frequency band | |
| Mester et al. | Development and drift-analysis of a modular electromagnetic induction system for shallow ground conductivity measurements | |
| CN110263482B (en) | Eddy impedance solving method and device based on cross correlation algorithm | |
| JP6621515B1 (en) | Ground capacitance measuring apparatus and ground capacitance measuring method | |
| JP4369909B2 (en) | Magnetic property measuring method and measuring instrument | |
| CA2372866A1 (en) | Proximity sensor method and apparatus that is insensitive to temperature, noise and length of wire | |
| CN107328987B (en) | Method and device for processing waveform distortion of photoelectric current sensor | |
| CN112180179B (en) | Electromagnetic compatibility analysis method and device | |
| CN111521958B (en) | Low-frequency magnetic field measuring method, device, electronic equipment and storage medium | |
| CN109073775A (en) | The detection device of coefficient 1 and induction type | |
| EP3296752A1 (en) | Improvements in or relating to the measurement of current within a conductor | |
| CN113687289A (en) | Measuring and self-calibrating method and system of non-contact type miniature voltage sensor |
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 |