Iron core magnetic field coil constant measuring method based on magnetic flux variable

Abstract

An iron core magnetic field coil constant measuring method based on a magnetic flux variable comprises the steps that a magnetic flux measuring coil is arranged outside a measured coil, then a drive circuit of the measured coil is used for generating a step current signal or rapidly turning NS polarity in an electrified mode, and magnetic flux changes are measured through the magnetic flux measuring coil; the magnetic flux measuring coil measures the variable quantity of the magnetic flux, and then the constant of the measured magnetic field coil is calculated according to the measured driving current. The method can solve the problem that the constant of the magnetic field coil with the iron core cannot be accurately measured, and is convenient to implement.

Description

Technical Field

[0001] The present invention relates to the field of magnetic metrology technology, and in particular to a method for measuring an "iron core" magnetic field coil constant based on a magnetic flux variable, wherein the "iron core" generally refers to an inner core material with high magnetic permeability, and does not specifically refer to "iron". Background Art

[0002] The magnetic field coil is a key device commonly used in the field of magnetic metrology to generate magnetic fields. Nowadays, with the advancement of technology, in order to solve the problem of in-situ calibration of fluxgate sensors (magnetometers), a new technology with a magnetic field coil for internal calibration has been developed. This technology uses the enameled wire winding wound on the probe wire frame (or coaxial wire frame) in the fluxgate sensor (magnetometer) probe to establish a calibration coil. When a certain excitation current passes through the coil, a magnetic field is generated inside it. By observing whether the change in the sensor output magnetic field meets the expected magnetic field change range, the fluxgate sensor (magnetometer) is calibrated.

[0003] In this probe, the magnetic field coil is tightly integrated with the sensor probe and can be regarded as a magnetic field coil with an iron core. The measurement methods used in the existing verification procedures and calibration specifications cannot solve this type of magnetic field coil. The existing methods mainly include the magnetic field vector method, the magnetic field scalar method, and the standard coil method. All of them require the standard magnetometer to be placed inside the magnetic field coil to be measured, and the magnetic field coil constant is calibrated by measuring the changes in magnetic induction intensity and the changes in excitation current. The mechanical structure of the magnetic field coil with an iron core determines that the existing measurement method cannot solve the calibration problem. Summary of the invention

[0004] The present invention provides a method for measuring the constant of an "iron core" magnetic field coil based on magnetic flux variables, which utilizes the magnetic flux changes to achieve the measurement of the coil constant and solves the problem that the constant of a magnetic field coil with an iron core cannot be accurately measured.

[0005] The method for measuring the constant of an "iron core" magnetic field coil provided in the present disclosure mainly comprises the following steps:

[0006] S1, set a magnetic flux measurement coil, which is sleeved outside the magnetic field coil with an iron core; set a signal source, which is connected to the magnetic field coil with an iron core and provides a driving current to it;

[0007] S2, causes the magnetic field of the magnetic field coil with an iron core to change rapidly, thereby changing the magnetic flux Φ passing through the magnetic flux measuring coil;

[0008] S3, measuring the magnetic flux change ΔΦ using a magnetic flux measuring coil;

[0009] S4, measure the driving current I through the magnetic field coil with iron core, according to the measurement coil constant K of the flux measurement coil calibrated in advance Φ, as well as the measured ΔΦ and I, calculate the coil constant of the magnetic field coil with an iron core.

[0010] Furthermore, the specific method of step S2 includes:

[0011] A step current signal is generated by using a driving circuit with an iron core magnetic field coil;

[0012] Or: energize the iron core magnetic field coil and quickly flip the NS polarity.

[0013] Furthermore, the specific method of step S3 includes:

[0014] S31, the flux measurement coil is sensitive to the flux change and generates an induced voltage:

[0015] Among them, ε is the induced voltage, Φ is the magnetic flux passing through the measuring coil;

[0016] S32, continuously measuring the induced voltage and integrating the measured value to obtain the magnetic flux change ΔΦ.

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

[0018]

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

[0020] K Φ It is the flux measurement coil constant, that is, the coil turn area NA is measured.

[0021] Furthermore, the magnetic flux measurement coil adopts a solenoid coil or a Helmholtz coil structure, and its uniform area is sufficient to accommodate the object to be measured.

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

[0023] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0024] Figure 1 Schematic diagram of the structure of the fluxgate sensor probe with a calibration magnetic field coil;

[0025] Figure 2Instruments and devices used for measuring according to exemplary embodiments of the present disclosure and their components;

[0026] Figure 3 A flow chart of an exemplary embodiment. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying 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. On the contrary, these embodiments are provided to make the present disclosure 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 measuring the constant of a magnetic field coil with an iron core based on a magnetic flux variable. The method utilizes the interaction between the magnetic flux measurement coil and the magnetic field coil with an iron 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. Its magnitude is proportional to the rate of change of the magnetic flux, and the mathematical expression is: Among them, ε is the induced electromotive force and Φ is the magnetic flux passing through the measuring coil.

[0030] The relationship between the magnetic flux Φ passing through the measuring coil, the magnetic field B therein and the measuring coil turn area NA is expressed as: Φ=B·NA·cosθ, where θ is the angle between the measuring coil plane and the magnetic field direction of the iron core magnetic field coil.

[0031] In one exemplary embodiment:

[0032] The instruments and equipment used for measurement are mainly: flux measurement coil, flux meter (or data acquisition device + integration processing software), power supply, ammeter (or current measurement system). Figure 2 shown.

[0033] The specific measurement implementation process is shown in the attached Figure 3 As shown:

[0034] 1) A step current signal is generated by using a driving circuit with an iron core magnetic field coil, and a charged and fast NS polarity reversal operation of the iron core magnetic field coil can also be performed.

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

[0036] 3) According to the measurement coil constant K of the pre-calibrated flux measurement coil Φ(i.e. measuring the coil turn area NA) and the driving current I through the iron core magnetic field coil measured by current, calculate the coil constant of the iron core magnetic field coil, the formula is: Where K B is the coil constant of the field coil with iron core.

[0037] Among them, the sampling flux measurement coil. The main technical requirements are:

[0038] The uniform area of ​​the flux measurement coil is large enough to accommodate the object being measured;

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

[0040] The above technical scheme is only an exemplary embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific embodiment of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

Claims

1. A method for measuring the constant of an "iron core" magnetic field coil based on a magnetic flux variable, comprising the following steps: S1, set a magnetic flux measurement coil, which is placed outside the magnetic field coil with an iron core; Set up a signal source, connect it to the magnetic field coil with an iron core, and provide it with a driving current; S2, causes the magnetic field of the magnetic field coil with an iron core to change rapidly, thereby changing the magnetic flux Φ passing through the magnetic flux measuring coil; S3, measuring the magnetic flux change ΔΦ using a magnetic flux measuring coil; S4, measure the driving current I through the magnetic field coil with iron core, according to the measurement coil constant K of the flux measurement coil calibrated in advance Φ , as well as the measured ΔΦ and I, calculate the coil constant of the magnetic field coil with an iron core.

2. The method according to claim 1, characterized in that The specific method of step S2 includes: A step current signal is generated by using a driving circuit with an iron core magnetic field coil; Or: energize the iron core magnetic field coil and quickly flip the NS polarity.

3. The method according to claim 1, characterized in that The specific method of step S3 includes: S31, the flux measurement coil is sensitive to the flux change and generates an induced voltage: Among them, ε is the induced voltage, Φ is the magnetic flux passing through the measuring coil; S32, continuously measuring the induced voltage and integrating the measured value to obtain the magnetic flux change ΔΦ.

4. The method according to claim 1, characterized in that In step S4, the coil constant calculation formula of the iron core magnetic field coil is: Among them, K B is the coil constant of the magnetic field coil with iron core; K Φ It is the flux measurement coil constant, that is, the coil turn area NA is measured.

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

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