A method for measuring the constant of a magnetic field coil with a core based on magnetic flux variation

Abstract

A kind of constant measurement method of magnetic field coil with core based on magnetic flux variable, by setting magnetic flux measuring coil outside the measured coil, then using the drive circuit of measured coil to generate step current signal or carry out fast flip NS polarity with electricity, make through the magnetic flux measuring coil measure the change of magnetic flux;Magnetic flux measuring coil measures the change of magnetic flux, and then according to the measured driving current, the measured magnetic field coil constant is calculated.The method can solve the problem that the constant of magnetic field coil with core cannot be accurately measured, and is convenient to implement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetometry, in particular to a method for measuring the constant of a magnetic field coil with a core based on magnetic flux variation. BACKGROUND

[0002] Magnetic field coils are key devices for generating magnetic fields in the field of magnetometry. Today, with the advancement of technology, in order to solve the problem of in-situ calibration of fluxgate sensors (magnetometers), a new technology of magnetic field coil with calibration function has been developed. This technology uses the enameled wire winding on the probe frame (or coaxial frame) of the fluxgate sensor (magnetometer) probe to establish a calibration coil. When a certain excitation current is applied to the coil, a magnetic field is generated inside the coil. By observing whether the change of the sensor output magnetic field conforms to the designed expected magnetic field change range, the calibration of the fluxgate sensor (magnetometer) is realized.

[0003] This kind of probe, the magnetic field coil is closely combined with the sensor probe, and can be regarded as a kind of magnetic field coil with a core. The existing measurement methods used in the existing verification regulations and calibration specifications cannot solve the calibration problem of this kind of magnetic field coil. The existing methods mainly include magnetic field vector method, magnetic field scalar method and standard coil method, all of which need to place the standard magnetometer inside the measured magnetic field coil, and realize the calibration of the magnetic field coil constant by measuring the change of magnetic induction intensity and the change of excitation current. The mechanical structure of the magnetic field coil with a core determines that the existing measurement methods cannot solve the calibration problem. SUMMARY

[0004] The present application provides a method for measuring the constant of a magnetic field coil with a core based on magnetic flux variation, which uses magnetic flux variation to measure the constant of the coil, and solves the problem of inaccurate measurement of the constant of the magnetic field coil with a core.

[0005] The method for measuring the constant of a magnetic field coil with a core provided by the present application mainly includes the following steps:

[0006] S1, setting a magnetic flux measuring coil around the magnetic field coil with a core; setting a signal source connected to the magnetic field coil with a core to provide a driving current thereto;

[0007] S2, rapidly changing the magnetic field of the magnetic field coil with a core to change the magnetic flux passing through the magnetic flux measuring coil ;

[0008] S3, measuring the change of magnetic flux by the magnetic flux measuring coil ;

[0009] S4, measuring the driving current I passing through the magnetic field coil with a core, and according to the measurement coil constant K of the magnetic flux measuring coil calibrated in advance ΦAnd measured And I, the coil constant of the magnetic field coil with core is calculated.

[0010] Further, the step S2 includes the following specific methods.

[0011] A step of generating a step current signal by using a driving circuit of the magnetic field coil with core.

[0012] Or: quickly flip the NS polarity of the magnetic field coil with core.

[0013] Further, the step S3 includes the following specific methods.

[0014] S31, the magnetic flux measuring coil senses the change of the magnetic flux and generates an induced voltage:

[0015] Wherein, is the induced voltage, is the magnetic flux passing through the measuring coil;

[0016] S32, continuously measure the induced voltage and integrate the measured value to obtain the change amount of the magnetic flux .

[0017] Further, in the step S4, the coil constant calculation formula of the magnetic field coil with core is:

[0018]

[0019] Wherein, K B is the coil constant of the magnetic field coil with core;

[0020] K Φ is the constant of the magnetic flux measuring coil, i.e. the turn area NA of the measuring coil.

[0021] Further, the magnetic flux measuring coil adopts a solenoid coil or a Helmholtz coil structure, which has a uniform area sufficient to accommodate the measured object.

[0022] Compared with the prior art, the beneficial effects of the present disclosure are: (1) compared with the prior art, the problem of the coil constant of the magnetic field coil with core cannot be measured can be solved; (2) based on the existing technical means, the difficulty of implementation is low; (3) the amount of equipment used is small. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of exemplary embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which like reference characters refer to the like parts throughout the figures, and in which:

[0024] Figure 1Structure diagram of a fluxgate sensor probe with calibration magnetic field coil

[0025] Figure 2 Instrument equipment used for measurement and its composition for example embodiments according to the present disclosure

[0026] Figure 3 Flow chart for example embodiments. DETAILED DESCRIPTION

[0027] Preferred embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. Although preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure is more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0028] The present disclosure provides a method for constant measurement of a magnetic field coil with a core based on magnetic flux variables. The method is realized by utilizing the interaction between the magnetic flux measurement coil and the magnetic field coil with a core, and the basic physical principle involved is Faraday's law of electromagnetic induction. Specifically, it includes:

[0029] According to Faraday's law of electromagnetic induction, when the magnetic flux in a closed coil changes, an induced electromotive force will be generated in the closed coil. The magnitude is proportional to the rate of change of the magnetic flux, and the mathematical expression is: Where, is the induced electromotive force, is the magnetic flux passing through the measurement coil.

[0030] The relationship between the magnetic flux Φ passing through the measurement coil and the magnetic field B in it and the measurement coil turn area NA is expressed as: Where θ is the angle between the plane of the measurement coil and the direction of the magnetic field of the magnetic field coil with a core.

[0031] In an example embodiment:

[0032] The instrument equipment used for measurement mainly includes: a magnetic flux measurement coil, a magnetic flux meter (or a data acquisition device + integral processing software), a power supply, and an ammeter (or a current measurement system). The measurement principle is as shown in Figure 2 .

[0033] The specific measurement implementation process is shown in the accompanying Figure 3 .

[0034] 1) A step current signal is generated using the drive circuit of the magnetic field coil with a core, and the NS polarity operation of the magnetic field coil with a core can also be performed quickly with electricity.

[0035] 2) The magnetic flux measuring coil measures the magnetic flux change and outputs the induced voltage to the magnetic flux meter or data collector to measure the magnetic flux change .

[0036] 3) According to the measurement coil constant of the magnetic flux measuring coil calibrated in advance (the measurement coil turn area NA) and the drive current I of the magnetic field coil with core measured by the current measurement, the coil constant of the magnetic field coil with core is calculated, and the formula is: , wherein is the coil constant of the magnetic field coil with core.

[0037] Among them, the sampled magnetic flux measuring coil. The main technical requirements are:

[0038] The uniform area of the magnetic flux measuring coil is sufficient to accommodate the measured object;

[0039] The magnetic flux measuring coil can usually adopt a solenoid coil or a Helmholtz coil structure.

[0040] The above technical solution is only an exemplary embodiment of the present application, and for those skilled in the art, on the basis of the application disclosed application method and principle, various types of improvement or deformation can be easily made, and is not limited to the method described in the above specific embodiments of the present application, therefore the above described method is only preferred, and does not have the meaning of limitation.

Claims

1. A method for measuring the constant of a magnetic field coil with a core based on the variable of magnetic flux, comprising the following steps: S1. Setting a magnetic flux measuring coil around the magnetic field coil with a core; Setting a signal source connected to the magnetic field coil with a core to provide a driving current; S2. Rapidly changing the magnetic field of the magnetic field coil with a core to change the magnetic flux Φ passing through the magnetic flux measuring coil; S3, measuring the amount of change in magnetic flux with a magnetic flux measuring coil ; S4, measuring the drive current I through the ferromagnetic field coil, calculating the coil constant of the ferromagnetic field coil from the measurement coil constant of the magnetic flux measurement coil, which has been calibrated in advance and the measured and I, calculating the coil constant of the ferromagnetic field coil; In the step S4, the formula for calculating the constant of the magnetic field coil with a core is: K B is the coil constant of the core field coil; K Φ is the magnetic flux measurement coil constant, i.e. the measurement coil turn area NA.

2. The method of claim 1, wherein, The specific method of the step S2 includes: Using the driving circuit of the magnetic field coil with a core to generate a step current signal; Or: quickly flipping the NS polarity of the magnetic field coil with a core with electricity.

3. The method of claim 1, wherein, The specific method of the step S3 includes: S31. The magnetic flux measuring coil senses the change of magnetic flux to generate an induced voltage: where ε is the induced voltage and Φ is the magnetic flux passing through the measurement coil. S32, continuously measure the induced voltage and integrate the measurement value to obtain the magnetic flux change amount .

4. The method according to any one of claims 1 to 3, characterized in that, The magnetic flux measuring coil adopts a solenoid coil or a Helmholtz coil structure, and its uniform region is sufficient to accommodate the measured object.

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