阅读说明：本技术 一种直流磁场强度的测试方法 (Method for testing direct-current magnetic field intensity ) 是由 杜建科 丁雪 丁本杰 金育安 张明华 李光勇 娄佳 华李成 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种直流磁场强度的测试方法,包括正弦信号发生器、信号幅度放大模块、激光测振仪、NI采集卡和横向场激励的磁场传感器；优点是本方法通过横向场激励下磁场传感器的谐振频率来判断直流磁场强度,克服了温度对磁场传感器的影响；而且通过磁场传感器三种不同振动模态下的谐振频率来判断不同强度范围的直流磁场,实现了直流磁场强度的准确测试；又由于磁场传感器上的正、负电极位于压电材料层的同一侧,使得所有的电极及引线均置于磁场传感器的后端,消除了电极对磁场探测信号的干扰与衰减,进一步确保了磁场强度测试的准确性。(The invention discloses a method for testing the intensity of a direct-current magnetic field, which comprises a sinusoidal signal generator, a signal amplitude amplification module, a laser vibration meter, an NI acquisition card and a transverse field excited magnetic field sensor, wherein the sinusoidal signal generator is connected with the signal amplitude amplification module; the method has the advantages that the method judges the intensity of the direct-current magnetic field through the resonance frequency of the magnetic field sensor under the excitation of the transverse field, and overcomes the influence of temperature on the magnetic field sensor; the direct-current magnetic fields in different strength ranges are judged through the resonance frequencies of the magnetic field sensor in three different vibration modes, so that the accurate test of the direct-current magnetic field strength is realized; and because the positive electrode and the negative electrode on the magnetic field sensor are positioned on the same side of the piezoelectric material layer, all the electrodes and the leads are arranged at the rear end of the magnetic field sensor, the interference and the attenuation of the electrodes on a magnetic field detection signal are eliminated, and the accuracy of the magnetic field intensity test is further ensured.)

1. A method for testing the strength of a direct-current magnetic field is characterized in that a testing system used by the method comprises a sinusoidal signal generator, a signal amplitude amplification module, a laser vibration meter, an NI acquisition card and a transverse field excitation magnetic field sensor, wherein the magnetic field sensor comprises a piezoelectric material layer and a piezomagnetic material layer which are bonded and fixed with each other, a positive electrode and a negative electrode are arranged on one surface of the piezoelectric material layer, the surface where the positive electrode and the negative electrode are positioned is opposite to the bonding surface of the piezoelectric material layer and the piezomagnetic material layer so as to realize the transverse field excitation of the magnetic field sensor, the sinusoidal signal generator is respectively electrically connected with the signal amplitude amplification module and the NI acquisition card, the signal amplitude amplification module and the laser vibration meter are respectively electrically connected with the magnetic field sensor, and the laser vibration meter is electrically connected with the NI acquisition card, the method comprises the following specific steps:

(1) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to generate first-order bending vibration;

(2) in the frequency range of the sweep frequency determined in the step (1), a sinusoidal signal generator excites a magnetic field sensor through a signal amplitude amplification module, and meanwhile, the sinusoidal signal generator transmits the sinusoidal signal as a reference signal to an NI acquisition card and sends the reference signal to the own software of the laser vibration meter through the NI acquisition card;

(3) placing the magnetic field sensor in the first-order bending vibration mode in a direct-current magnetic field with known magnetic field intensity, measuring vibration displacement and vibration frequency of the magnetic field sensor in the sweep frequency range determined in the step (1) by using a laser vibration meter, wherein the vibration displacement and the vibration frequency are acquired signals, and the acquired signals are transmitted to self-contained software of the laser vibration meter in the form of electric signals through an NI acquisition card;

(4) sequentially placing the magnetic field sensors in the first-order bending vibration mode in direct-current magnetic fields with different magnetic field strengths, repeating the step (3), measuring the resonant frequency of the corresponding magnetic field sensors one by one through an NI acquisition card and a laser vibration meter, then obtaining a magnetic field strength relation graph of the resonant frequency of the magnetic field sensors in the first-order bending vibration mode and the direct-current magnetic field through Origin software, and recording a section of corresponding magnetic field strength range of which the resonant frequency and the magnetic field strength are in a linear relation on the relation graph;

(5) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to be in second-order bending vibration;

(6) repeating the operations of the steps (2) to (4) within the frequency sweep frequency range determined in the step (5) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor and the direct-current magnetic field under the second-order bending vibration mode, and recording a magnetic field strength range corresponding to a section of the relation graph in which the resonant frequency and the magnetic field strength are in a linear relation;

(7) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to be in thickness shear vibration;

(8) repeating the operations of the steps (2) to (4) within the sweep frequency range determined in the step (7) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor and the direct-current magnetic field under the thickness shear vibration mode, and recording a magnetic field strength range corresponding to a section of the relation graph in which the resonant frequency and the magnetic field strength are in a linear relation;

(9) selecting a vibration mode corresponding to the linear relation between the resonant frequency and the magnetic field strength in the range of the magnetic field strength according to the range of the magnetic field strength of the direct-current magnetic field to be tested and the relationship diagram obtained in the steps (4), (6) and (8), regulating the magnetic field sensor to the vibration mode, regulating the output signal of the sine signal generator to the corresponding frequency range, exciting the magnetic field sensor by the sine signal generator, sending the electric signal to software carried by the laser vibration meter by an NI acquisition card by the sine signal generator as an actually-measured reference signal, placing the magnetic field sensor in the direct-current magnetic field to be tested, measuring the actually-measured vibration displacement and the actually-measured vibration frequency of the magnetic field sensor in the frequency range by the laser vibration meter, wherein the actually-measured vibration displacement and the actually-measured vibration frequency are actually-measured acquisition signals, and sending the actually-measured acquisition signals to soft NI carried by the laser vibration meter by the acquisition card in the form of electric signals And finally, according to a relation graph of the resonant frequency and the magnetic field intensity under the vibration mode, obtaining the accurate magnetic field intensity of the measured direct-current magnetic field through matlab software analysis.

2. The method for testing the magnitude of a direct current magnetic field according to claim 1, wherein: the piezoelectric material layer is made of piezoelectric ceramics with inverse piezoelectric effect, quartz, lanthanum gallium tantalate, lead magnesium niobate-lead titanate, lithium tantalate, lithium niobate or lead zirconate titanate, and the piezomagnetic material layer is made of rare earth ferromagnetic material.

Technical Field

The invention relates to a test of magnetic field parameters, in particular to a test method of direct-current magnetic field intensity.

Background

The current direct-current magnetic field measuring method mainly comprises a Hall element detection method, a running water type NMR field measuring method, a reed pipe magnetic field detection method, a fluxgate magnetometer method and the like. Among the methods, the Hall element detection method has the advantages of small volume, simple structure, wide frequency response, large output voltage change, long service life and the like, but the interchangeability is poor, and the heating can be caused by overlong working time of a measurement circuit, so that a Hall voltmeter in a circuit system of the Hall element generates measurement errors, and unequal potential caused by incomplete symmetry of electrode positions is generated. The flowing water NMR field measuring instrument requires pre-polarizing of the flowing water sample with a strong magnetic field, which can be difficult to detect weak magnetic fields, and also presents accuracy problems, such as quantization error of digital frequency meter readings, influence of diamagnetic susceptibility of water, and influence of detector noise. The reed switch magnetic field detection structure is simple, small in size and convenient to control, but the response time is long. The fluxgate magnetometer has high sensitivity and convenient carrying, but the circuit is complex, the circuit parameter is greatly influenced by the temperature and the debugging difficulty is difficult.

Therefore, it is of great significance to provide a method for measuring a direct current magnetic field, which has high sensitivity and high measurement accuracy, can detect strong and weak magnetic fields, and is not affected by temperature.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for testing the intensity of a direct-current magnetic field, which can overcome the influence of temperature on a sensor and ensure that the test of the intensity of the magnetic field is accurate.

The technical scheme adopted by the invention for solving the technical problems is as follows: a test method of direct current magnetic field intensity, the test system used by it includes sine signal generator, signal amplitude amplifying module, laser vibration meter, NI collecting card and magnetic field sensor excited by transverse field, the said magnetic field sensor includes piezoelectric material layer and piezomagnetic material layer which are fixed by binding, one of the surfaces of the said piezoelectric material layer is set with positive electrode and negative electrode, the surface of the said positive electrode and the said negative electrode is opposite to the binding surface of the said piezoelectric material layer and the said piezomagnetic material layer, to realize the transverse field excitation of the magnetic field sensor, the said sine signal generator is connected with the said signal amplitude amplifying module and the said NI collecting card, the said signal amplitude amplifying module and the said laser vibration meter are connected with the said magnetic field sensor, the said laser vibration meter is connected with the said NI collecting card, the method comprises the following specific steps:

(1) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to generate first-order bending vibration;

(2) in the frequency range of the sweep frequency determined in the step (1), a sinusoidal signal generator excites a magnetic field sensor through a signal amplitude amplification module, and meanwhile, the sinusoidal signal generator transmits the sinusoidal signal as a reference signal to an NI acquisition card and sends the reference signal to the own software of the laser vibration meter through the NI acquisition card;

(3) placing the magnetic field sensor in the first-order bending vibration mode in a direct-current magnetic field with known magnetic field intensity, measuring vibration displacement and vibration frequency of the magnetic field sensor in the sweep frequency range determined in the step (1) by using a laser vibration meter, wherein the vibration displacement and the vibration frequency are acquired signals, and the acquired signals are transmitted to self-contained software of the laser vibration meter in the form of electric signals through an NI acquisition card;

(4) sequentially placing the magnetic field sensors in the first-order bending vibration mode in direct-current magnetic fields with different magnetic field strengths, repeating the step (3), measuring the resonant frequency of the corresponding magnetic field sensors one by one through an NI acquisition card and a laser vibration meter, then obtaining a magnetic field strength relation graph of the resonant frequency of the magnetic field sensors in the first-order bending vibration mode and the direct-current magnetic field through Origin software, and recording a section of corresponding magnetic field strength range of which the resonant frequency and the magnetic field strength are in a linear relation on the relation graph;

(5) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to be in second-order bending vibration;

(6) repeating the operations of the steps (2) to (4) within the frequency sweep frequency range determined in the step (5) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor and the direct-current magnetic field under the second-order bending vibration mode, and recording a magnetic field strength range corresponding to a section of the relation graph in which the resonant frequency and the magnetic field strength are in a linear relation;

(7) adjusting the distance between a positive electrode and a negative electrode on the magnetic field sensor, and enabling the sine signal generator to generate frequency sweep by setting an output signal of the sine signal generator, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor to be in thickness shear vibration;

(8) repeating the operations of the steps (2) to (4) within the sweep frequency range determined in the step (7) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor and the direct-current magnetic field under the thickness shear vibration mode, and recording a magnetic field strength range corresponding to a section of the relation graph in which the resonant frequency and the magnetic field strength are in a linear relation;

(9) selecting a vibration mode corresponding to the linear relation between the resonant frequency and the magnetic field strength in the range of the magnetic field strength according to the range of the magnetic field strength of the direct-current magnetic field to be tested and the relationship diagram obtained in the steps (4), (6) and (8), regulating the magnetic field sensor to the vibration mode, regulating the output signal of the sine signal generator to the corresponding frequency range, exciting the magnetic field sensor by the sine signal generator, sending the electric signal to software carried by the laser vibration meter by an NI acquisition card by the sine signal generator as an actually-measured reference signal, placing the magnetic field sensor in the direct-current magnetic field to be tested, measuring the actually-measured vibration displacement and the actually-measured vibration frequency of the magnetic field sensor in the frequency range by the laser vibration meter, wherein the actually-measured vibration displacement and the actually-measured vibration frequency are actually-measured acquisition signals, and sending the actually-measured acquisition signals to soft NI carried by the laser vibration meter by the acquisition card in the form of electric signals And finally, according to a relation graph of the resonant frequency and the magnetic field intensity under the vibration mode, obtaining the accurate magnetic field intensity of the measured direct-current magnetic field through matlab software analysis.

The piezoelectric material layer is made of piezoelectric ceramic with an inverse piezoelectric effect, quartz, lanthanum gallium tantalate, lead magnesium niobate-lead titanate, lithium tantalate, lithium niobate or lead zirconate titanate, and the piezomagnetic material layer is made of a rare earth ferromagnetic material.

Compared with the prior art, the method has the advantages that the method judges the intensity of the direct-current magnetic field through the resonance frequency of the magnetic field sensor under the excitation of the transverse field, and overcomes the influence of temperature on the magnetic field sensor; the direct-current magnetic field strength is sensed by directly measuring the vibration frequency of the magnetic field sensor in a non-contact manner by using the laser vibration meter, and the direct-current magnetic fields in different strength ranges are judged by the resonance frequency of the magnetic field sensor under three different vibration modes, so that the accurate test of the direct-current magnetic field strength is realized; and because the positive electrode and the negative electrode on the magnetic field sensor are positioned on the same side of the piezoelectric material layer, all the electrodes and the leads are arranged at the rear end of the magnetic field sensor, the interference and the attenuation of the electrodes on a magnetic field detection signal are eliminated, and the accuracy of the magnetic field intensity test is further ensured. In addition, the method adopts the magnetic field sensor excited by the transverse field, experiments show that the change of the vibration mode of the magnetic field sensor can be realized by controlling the distance between the positive electrode and the negative electrode, and the magnetic field sensor excited by the transverse field has better electrical property sensitivity and dynamic inductive reactance and better frequency stability.

Drawings

FIG. 1 is a schematic diagram of the connection of a test system used in the present invention;

FIG. 2 is a schematic diagram of the magnetic field sensor of the present invention;

FIG. 3 is a graph of the relationship between the resonant frequency of the magnetic field sensor and the magnetic field strength of the DC magnetic field in the first-order bending vibration mode according to the present invention;

FIG. 4 is a graph showing the relationship between the resonant frequency of the magnetic field sensor and the magnetic field strength of the DC magnetic field in the second-order bending vibration mode according to the present invention;

FIG. 5 is a graph showing the relationship between the resonant frequency of the magnetic field sensor and the magnetic field strength of the DC magnetic field in the thickness shear vibration mode.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in the figure, a testing method of direct current magnetic field intensity is provided, a testing system used by the testing method comprises a sinusoidal signal generator 1, a signal amplitude amplifying module 2, a laser vibration meter 3, an NI collecting card 4 and a transverse field excited magnetic field sensor 5, wherein the magnetic field sensor 5 comprises a piezoelectric material layer 51 and a piezomagnetic material layer 52 which are bonded and fixed with each other, a positive electrode 53 and a negative electrode 54 are arranged on one surface of the piezoelectric material layer 51, the surface where the positive electrode 53 and the negative electrode 54 are arranged is opposite to the bonding surface of the piezoelectric material layer 51 and the piezomagnetic material layer 52, in order to realize the transverse field excitation of the magnetic field sensor 5, the sinusoidal signal generator 1 is respectively and electrically connected with the signal amplitude amplification module 2 and the NI acquisition card 4, the signal amplitude amplification module 2 and the laser vibration meter 3 are respectively and electrically connected with the magnetic field sensor 5, and the laser vibration meter 3 is electrically connected with the NI acquisition card 4.

The specific test method of the direct-current magnetic field intensity is described by taking the direct-current magnetic field with the magnetic field intensity range of 0-1600 Oe as an example, and the specific steps are as follows:

(1) adjusting the distance between a positive electrode 53 and a negative electrode 54 on the magnetic field sensor 5, and setting an output signal of the sine signal generator 1 to enable the sine signal generator 1 to generate frequency sweep, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor 5 to generate first-order bending vibration;

(2) in the frequency sweep range determined in the step (1), the sinusoidal signal generator 1 excites the sinusoidal electrical signal to the magnetic field sensor 5 through the signal amplitude amplification module 2, and meanwhile, the sinusoidal signal generator 1 transmits the sinusoidal electrical signal as a reference signal to the NI acquisition card 4 and sends the reference signal to the self-contained software of the laser vibrometer 3 through the NI acquisition card 4;

(3) placing the magnetic field sensor 5 in the first-order bending vibration mode in a direct-current magnetic field with the magnetic field intensity of 200 Oe, measuring the vibration displacement and the vibration frequency of the magnetic field sensor 5 in the sweep frequency range determined in the step (1) through a laser vibration meter 3, wherein the vibration displacement and the vibration frequency are acquisition signals, and simultaneously sending the acquisition signals to software carried by the laser vibration meter 3 through an NI acquisition card 4 in the form of electric signals, and the software processes the received reference signals and the acquisition signals to obtain corresponding frequency response functions and the resonance frequency of the magnetic field sensor 5 in the direct-current magnetic field;

(4) sequentially placing the magnetic field sensors 5 in the first-order bending vibration mode in direct-current magnetic fields with different magnetic field strengths in the range of 0-1600 Oe, repeating the step (3), measuring the resonant frequency of the corresponding magnetic field sensors 5 one by one through an NI acquisition card 4 and a laser vibration meter 3, and then obtaining a magnetic field strength relation graph of the resonant frequency of the magnetic field sensors 5 in the first-order bending vibration mode and the direct-current magnetic field through Origin software, wherein the graph is shown in figure 3, and the relation graph shows that the resonant frequency and the magnetic field strength have a good linear relation when the magnetic field strength is in the range of 200-1600 Oe;

(5) adjusting the distance between a positive electrode 53 and a negative electrode 54 on the magnetic field sensor 5, and setting an output signal of the sine signal generator 1 to enable the sine signal generator 1 to generate frequency sweep, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor 5 to be in second-order bending vibration;

(6) repeating the operations of the steps (2) to (4) within the frequency sweep range determined in the step (5) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor 5 and the direct-current magnetic field in the second-order bending vibration mode, as shown in fig. 4, and from the relation graph, it can be known that the resonant frequency and the magnetic field strength have a good linear relation within the range of 100-1000 Oe of the magnetic field strength;

(7) adjusting the distance between a positive electrode 53 and a negative electrode 54 on the magnetic field sensor 5, and setting an output signal of the sine signal generator 1 to enable the sine signal generator 1 to generate frequency sweep, wherein the frequency range of the frequency sweep is to enable the magnetic field sensor 5 to be in thickness shear vibration;

(8) repeating the operations of the steps (2) to (4) within the frequency sweep range determined in the step (7) to obtain a magnetic field strength relation graph of the resonant frequency of the magnetic field sensor 5 and the direct-current magnetic field in the thickness shear vibration mode, as shown in fig. 5, and from the relation graph, it can be known that the resonant frequency and the magnetic field strength have a good linear relation within the range of 0-200 Oe of the magnetic field strength;

(9) when the magnetic field intensity of the direct-current magnetic field to be tested is less than 200 Oe, the magnetic field sensor 5 is regulated to thickness shearing vibration, the output signal of the sine signal generator 1 is regulated to a corresponding frequency range, the sine signal generator 1 excites the magnetic field sensor 5, meanwhile, the sine signal generator 1 sends an electric signal as an actual measurement reference signal to software carried by a laser vibration meter 3 through an NI acquisition card 4, then the magnetic field sensor 5 is placed in the direct-current magnetic field to be tested, the actual measurement vibration displacement and the actual measurement vibration frequency of the magnetic field sensor 5 in the frequency range are measured through the laser vibration meter 3, the actual measurement acquisition signal is an actual measurement acquisition signal, the actual measurement acquisition signal is sent to the software carried by the laser vibration meter 3 through the NI acquisition card 4 in the form of the electric signal, and the software processes the received actual measurement reference signal and the actual measurement acquisition signal to obtain a corresponding frequency response function and the corresponding frequency response function of the magnetic field sensor 5 in the direct-current magnetic field to be tested Actually measuring the resonant frequency in the magnetic field, and finally obtaining the accurate magnetic field intensity of the measured direct-current magnetic field through matlab software analysis according to a relation graph of the resonant frequency and the magnetic field intensity under a thickness shearing vibration mode; similarly, when the magnetic field strength of the direct-current magnetic field to be tested is greater than 1000 Oe, the magnetic field sensor 5 is regulated to first-order bending vibration, the output signal of the sinusoidal signal generator 1 is regulated to a corresponding frequency range, then the magnetic field sensor 5 is placed in the direct-current magnetic field to be tested, and the accurate magnetic field strength of the direct-current magnetic field to be tested is measured according to the method; when the magnetic field intensity of the direct current magnetic field to be tested is more than 200 Oe and less than 1000 Oe, the magnetic field sensor 5 can be regulated to first-order bending vibration or second-order bending vibration, and then the accurate magnetic field intensity of the direct current magnetic field to be tested is measured according to the method.

In the above embodiment, the material of the piezoelectric material layer 51 of the magnetic field sensor 5 may be a piezoelectric ceramic having an inverse piezoelectric effect, quartz, langasite tantalate, lead magnesium niobate-lead titanate, lithium tantalate, lithium niobate, or lead zirconate titanate, and the material of the piezomagnetic material layer 52 is a rare-earth ferromagnetic material.

In the above embodiment, the principle of using the resonant frequency of the magnetic field sensor 5 to measure the dc magnetic field strength is as follows: the sinusoidal electrical signal generated by the sinusoidal signal generator 1 is used for exciting the magnetic field sensor 5 through the signal amplitude amplification module 2, the piezoelectric material layer 51 in the magnetic field sensor 5 is excited by the sinusoidal electrical signal and vibrates due to the inverse piezoelectric effect, so that the piezomagnetic material layer 52 is driven to vibrate, when the natural frequency of the magnetic field sensor 5 is the same as the frequency generated by the sinusoidal signal generator, the magnetic field sensor 5 generates resonance, and the frequency at this time is the resonance frequency; when the magnetic field sensor 5 is located in the dc magnetic field, the piezomagnetic material layer 52 is affected by the magnetic field and is elongated or shortened, and the resonant frequency of the magnetic field sensor 5 is changed, so that the strength of the dc magnetic field is measured by the change of the resonant frequency.

The scope of the present invention includes, but is not limited to, the above embodiments, and the present invention is defined by the appended claims, and any alterations, modifications, and improvements that may occur to those skilled in the art are all within the scope of the present invention.