WO2020113467A1 - 一种感应式磁传感器及电磁勘探设备 - Google Patents

一种感应式磁传感器及电磁勘探设备 Download PDF

Info

Publication number
WO2020113467A1
WO2020113467A1 PCT/CN2018/119362 CN2018119362W WO2020113467A1 WO 2020113467 A1 WO2020113467 A1 WO 2020113467A1 CN 2018119362 W CN2018119362 W CN 2018119362W WO 2020113467 A1 WO2020113467 A1 WO 2020113467A1
Authority
WO
WIPO (PCT)
Prior art keywords
coil
magnetic sensor
low
circuit
measurement
Prior art date
Application number
PCT/CN2018/119362
Other languages
English (en)
French (fr)
Inventor
底青云
真齐辉
王煜亮
刘志尧
杨全民
Original Assignee
中国科学院地质与地球物理研究所
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 中国科学院地质与地球物理研究所 filed Critical 中国科学院地质与地球物理研究所
Priority to PCT/CN2018/119362 priority Critical patent/WO2020113467A1/zh
Publication of WO2020113467A1 publication Critical patent/WO2020113467A1/zh
Priority to US17/115,808 priority patent/US11914092B2/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/081—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices the magnetic field is produced by the objects or geological structures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45479—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection
    • H03F3/45928—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection using IC blocks as the active amplifying circuit
    • H03F3/45968—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection using IC blocks as the active amplifying circuit by offset reduction
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/168—Two amplifying stages are coupled by means of a filter circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/261—Amplifier which being suitable for instrumentation applications
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/294—Indexing scheme relating to amplifiers the amplifier being a low noise amplifier [LNA]
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45138—Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45526—Indexing scheme relating to differential amplifiers the FBC comprising a resistor-capacitor combination and being coupled between the LC and the IC
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45534—Indexing scheme relating to differential amplifiers the FBC comprising multiple switches and being coupled between the LC and the IC
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45621—Indexing scheme relating to differential amplifiers the IC comprising a transformer for phase splitting the input signal

Definitions

  • the invention relates to the field of exploration geophysics, in particular to an inductive magnetic sensor and electromagnetic exploration equipment.
  • An inductive magnetic sensor (hereinafter referred to as a magnetic sensor) is a device based on Faraday's law of electromagnetic induction, which uses the relationship between the output voltage of the coil and the amount of change in the magnetic flux passing through the coil to directly measure the magnetic field by measuring the output voltage of the coil.
  • the characteristic of MT magnetic sensor is to obtain low-frequency and ultra-low-frequency magnetic field signals. By winding tens of thousands of turns on a high-permeability magnetic core, a low-noise amplifier circuit and a magnetic flux negative feedback structure are used to convert the magnetic field into a measurement voltage.
  • FIG. 1 an equivalent circuit diagram of an inductive magnetic sensor is shown, in which
  • Cp is the measurement coil parasitic capacitance
  • Lp is the measurement coil self-inductance
  • Rp is the measurement coil resistance
  • Ls is the feedback coil self-inductance
  • Rfb is the feedback resistance
  • M is the mutual inductance between the feedback coil and the measurement coil
  • Np and Ns are the turns of the measuring coil and the feedback coil, respectively;
  • A is the magnification of the amplifier circuit
  • vout is the output of the amplifier circuit
  • e is the induced electromotive force of the measuring coil.
  • the transfer function of the magnetic sensor can be obtained as:
  • ⁇ a is the effective permeability and S is the effective cross-sectional area of the magnetic circuit.
  • the methods used by these units or organizations are usually to determine the number of coil turns within the allowable range of volume and weight, and then use the method of improving the effective permeability of the magnetic core to improve the magnetic sensor. Sensitivity, and suppress low-frequency 1/f noise effects through the chopping and zero-stabilizing amplifier circuit.
  • the length of the core needs to be more than 1.0m, so that the length-to-diameter ratio is greater than 40:1 to achieve a sufficiently large effective permeability, which brings certain inconvenient.
  • some units or organizations have adopted a Flux Concentrator technology to make the effective magnetic permeability of shorter magnetic cores comparable to conventional elongated magnetic permeability, thereby miniaturizing magnetic field sensors.
  • the resonance frequency of the coil In order to stabilize the system, the resonance frequency of the coil must be higher than the measured passband frequency, and after the introduction of magnetic flux feedback, the quality factor of the magnetic sensor at the resonance frequency point is suppressed. There is no problem with this kind of thinking. It is necessary to ensure that the system has sufficient stability, which is the premise of system design. However, when measuring very low frequencies, the sensitivity of the extremely low frequency signal is extremely low, and the signal cannot be picked up normally. On the other hand, the high frequency noise is very large, resulting in a very low signal to noise ratio for low frequency measurement. Embarrassed.
  • embodiments of the present invention provide an inductive magnetic sensor and electromagnetic surveying equipment. Furthermore, the low-frequency characteristics of the magnetic sensor are expanded to obtain a more excellent low-frequency magnetic sensor.
  • the present invention provides an inductive magnetic sensor, including a signal pre-amplification measurement circuit, a feedback loop, a magnetic core and a coil, a low-noise stable-zero processing circuit, and an output protection module.
  • the input end of the coil and the A signal pre-amplification measurement circuit is electrically connected, the signal pre-amplification measurement circuit and the low-noise stabilization zero processing circuit, the output end of the coil is electrically connected to the feedback loop, the feedback loop and the low-noise
  • the zero-stabilization processing circuits are respectively electrically connected to the output protection modules.
  • the signal preamplification measurement circuit has a preamplifier unit and a resonant notch filter.
  • a capacitor is provided in parallel with the input end of the preamplifier unit.
  • the resonant trap is electrically connected to the low-noise stabilization processing circuit.
  • the signal preamplification measurement circuit has a preamplification unit.
  • the coil includes a feedback coil and a measurement coil, the feedback coil and the measurement coil are coupled and connected, the measurement coil is connected in parallel with the capacitor, and the feedback coil and the feedback loop are connection.
  • the signal preamplification measurement circuit includes two sets of preamplifier units and a resonant trap, which are a first preamplifier unit, a second preamplifier unit, and a first resonant trap And a second resonant notch filter, the first resonant notch filter and the second resonant notch filter use a first resistor connected together as an output terminal, and the output terminal is connected in parallel with a grounding capacitor to a reference ground.
  • the feedback loop switch is turned on.
  • the low-noise stabilization processing circuit uses a switching stabilization circuit.
  • the present invention provides an electromagnetic surveying apparatus having the inductive magnetic sensor as described above.
  • the invention provides an inductive magnetic sensor and electromagnetic exploration equipment, including a signal pre-amplification measurement circuit, a feedback loop, a magnetic core and a coil, a low-noise stable zero processing circuit, and an output protection module, the input end of the coil and the A signal pre-amplification measurement circuit is electrically connected, the signal pre-amplification measurement circuit and the low-noise stabilization zero processing circuit, the output end of the coil is electrically connected to the feedback loop, and the feedback loop and the low-noise
  • the zero-stabilization processing circuit is electrically connected to the output protection module respectively.
  • Figure 1 is an equivalent circuit diagram of an inductive magnetic sensor in the existing scheme
  • FIG. 2 is a circuit block diagram of an embodiment of an inductive magnetic sensor provided by the present invention.
  • FIG. 3 is a structural block diagram of a signal preamplification measurement circuit in an embodiment of an inductive magnetic sensor provided by the present invention
  • FIG. 4 is a schematic diagram of conversion characteristics in an embodiment of an inductive magnetic sensor provided by the present invention.
  • FIG. 5 is a schematic diagram of an inductive magnetic sensor provided by the present invention after incorporating a capacitor
  • FIG. 6 is a circuit diagram of a denoising circuit in an embodiment of an inductive magnetic sensor provided by the present invention.
  • FIG. 7 is a schematic diagram of the measured signal and circuit noise in an embodiment of the inductive magnetic sensor provided by the present invention.
  • FIG. 8 is a schematic diagram of input and output signals of a denoising circuit in an embodiment of an inductive magnetic sensor provided by the present invention.
  • FIG. 9 is a schematic diagram of low signal-to-noise ratio input in an embodiment of an inductive magnetic sensor provided by the present invention.
  • FIG. 10 is a schematic diagram of a circuit processing result of a low signal-to-noise ratio in an embodiment of an inductive magnetic sensor provided by the present invention
  • FIG. 11 is a schematic diagram of an output power spectrum of a denoising circuit in an embodiment of an inductive magnetic sensor provided by the present invention.
  • an embodiment of the present invention provides an inductive magnetic sensor, which includes a signal pre-amplification measurement circuit, a feedback loop, a magnetic core and a coil, a low-noise stable zero processing circuit, and an output protection module.
  • the input terminal is electrically connected to the signal preamplification measurement circuit, the signal preamplification measurement circuit and the low noise stable zero processing circuit, the output end of the coil is electrically connected to the feedback loop, and the feedback loop
  • the low-noise stabilization processing circuit is electrically connected to the output protection module, and through the introduction of the resonant notch filter, the bandwidth can be further extended to low frequencies, the low-frequency characteristics of the magnetic sensor can be expanded, and a more excellent low-frequency magnetic sensor can be obtained.
  • the signal preamplifier measurement circuit has a preamplifier unit and a resonant notch filter.
  • the resonant notch filter is used to measure the resonance frequency point of the coil for notching.
  • the input end of the preamplifier unit Capacitors are provided in parallel, and the resonant trap is electrically connected to the low-noise stabilization processing circuit.
  • the signal preamplification measurement circuit has a preamplifier unit.
  • the coil includes a feedback coil and a measurement coil, the feedback coil and the measurement coil are coupled and connected, the measurement coil is connected in parallel with the capacitor, and the feedback coil is electrically connected to the feedback loop.
  • the signal preamplification measurement circuit includes two sets of preamplifier units and resonant traps, which are the first preamplifier unit, second preamplifier unit, first resonant trap and second resonant trap, respectively.
  • the first resonant trap and the second resonant trap use an output connected by a first resistor as an output terminal, and the output terminal is connected in parallel with a grounding capacitor to a reference ground.
  • the low-noise and zero-stabilization processing circuit uses a switching zero-stabilization circuit or a chopping zero-zero operation amplifier, which can be flexibly selected in the art and is not limited thereto.
  • the inductive magnetic sensor provided by the present invention on the premise of optimizing the magnetic core, when measuring extremely low frequencies, incorporates a capacitor at the input end, because of the negative feedback of the magnetic flux, it will be difficult to affect the magnetic field conversion ability of the magnetic sensor. After the capacitor is incorporated, the closed loop is opened at the same time, so there is no problem of instability of self-oscillation. With the introduction of a notch filter, the bandwidth can be further extended to low frequencies. In order to circumvent the artifact problem of the traditional chopping zero-stabilizing amplifier circuit, a new zero-stabilizing magnetic sensor processing circuit is proposed, which further extends the low-frequency characteristics of the magnetic sensor and obtains a more excellent low-frequency magnetic sensor.
  • the inductive magnetic sensor provided by the present invention provides a solution by measuring a magnetic field signal below 100 Hz. For a magnetic field measurement above 100 Hz, it is necessary to remove both the input capacitance and the resonance trap and close the feedback loop.
  • the magnetic sensor of the present invention may include a high-permeability magnetic core, a coil, a low-noise amplifier circuit, and a feedback loop.
  • the difference is that the present invention adds two at the low-frequency measurement of the input end of the measuring coil.
  • the capacitor and low-noise amplifier circuit does not use the commonly used chopper amplifier, but a low-noise stable zero processing circuit specially designed to extend the low-frequency characteristics of the magnetic sensor.
  • Adding a capacitor to the preamplifier causes the resonance frequency of the magnetic sensor to move to a low frequency. After the resonance frequency is transferred, the negative feedback of the magnetic flux will no longer work.
  • the magnetic sensor only needs to perform open-loop measurement. There is no stability of self-excited oscillation. sexual issues.
  • the capacitor can also suppress the effect of high-frequency noise, and further increase the gain of the amplifier without saturation, so that the frequency characteristic of the magnetic sensor moves to the low-frequency direction, thereby achieving the purpose of spreading frequency.
  • the low-noise stabilization technology of the present invention adopts three stages of pre-amplification, filtering and stabilization.
  • This circuit has excellent stability characteristics, especially for 1/f noise, offset voltage, offset voltage temperature drift, offset current and offset current temperature drift suppression has very good performance.
  • the measured magnetic field frequency is lower than 100Hz, it is necessary to connect a capacitor Ci in parallel from the coil to the input of the preamplifier, and then cooperate with the resonant trap to ensure that the passband of the system moves further to the low frequency, and the feedback loop can be ignored.
  • the parallel capacitor at the input needs to be removed.
  • the resonant notch can not be used, and the notch is short-circuited to avoid destroying the normal measurement.
  • the resonant notch filter can also be replaced with a low-pass filter. It must be ensured that the measurement frequency is in the passband range, which can reduce the influence of high-frequency noise.
  • the signal pre-amplification measurement circuit is shown in Figure 3.
  • the signal pre-amplification measurement circuit has two completely identical circuits. The last two circuits are connected together to output through Ro, and a capacitor Co is connected to the reference ground in parallel at the output end.
  • N is the middle tap of the measuring coil
  • a and B are the upper and lower taps of the coil, respectively, and are sent to the dual input single output preamplifier, which is connected later
  • a resonant notch filter this resonant notch filter is mainly to further expand the passband to move to low frequencies and strengthen low frequency components.
  • the resonant notch wave is sent to the denoising core circuit of the circuit.
  • the circuit works in two modes through the switch control circuit.
  • the upper and lower circuits in Figure 3 show these two states respectively: one is tracking noise, and the noise The signal is stored on the capacitor C, as shown in the lower half of Figure 3; the other is to subtract the circuit noise signal stored on the capacitor C from the input signal, as shown in the lower half of Figure 3.
  • the upper and lower parts of the circuit in Figure 3 are complementary.
  • the other circuit works in the measurement state and outputs the measurement signal, which is filtered by Ro and capacitor Co as the output signal.
  • the selection of Ro and Co must ensure that the cut-off frequency is higher than the upper limit frequency of the measurement passband.
  • the invention can realize the goal of common use of one magnetic sensor in the frequency domain electromagnetic surveying method, can greatly reduce the volume and weight of the magnetic sensor, and bring great convenience to field construction.
  • An embodiment of the present invention provides an application scenario of an inductive magnetic sensor for illustration.
  • Figure 4 shows the conversion characteristics of the magnetic sensor. It can be seen that the resonance frequency of the magnetic sensor is 20kHz. After adding closed-loop magnetic flux negative feedback, the quality factor at the resonance point is greatly reduced, so that the system can work stably. When the measurement frequency is a low frequency of less than 100Hz, obviously such a high resonance frequency is not conducive to measurement. After incorporating a 2uF capacitor at the input of the preamplifier, the resonance point of the magnetic sensor moves to a low frequency to 170Hz. In order to make the system passband further Low frequency expansion, and increase the system gain, add a trap at the new resonance point. After incorporating the capacitor, the magnetic field conversion characteristics under different conditions are shown in Figure 5.
  • the conversion characteristics of the magnetic sensor after the capacitor is incorporated When the resonance is transferred to a low frequency, the closed loop basically does not work. The presence or absence of magnetic flux negative feedback has no effect on the magnetic sensor, so after the capacitor is incorporated, The effect of flux negative feedback can be ignored. If the notch filter is not introduced, the system will have a high conversion performance around 170 Hz, which affects the low-frequency measurement. After the introduction of the notch filter, the magnetic sensor is forced to lower the conversion performance at 170 Hz, so that the frequency band of the magnetic sensor is further reduced to the low frequency Extended, the magnetic sensor can obtain low-frequency signals without further saturation by further increasing the system gain.
  • the circuit is mainly 1/f noise, offset voltage, offset voltage temperature drift, offset current, offset current temperature drift, the frequency of these noises is very low, under sufficiently high switching frequency conditions, before and after the switch, the noise is considered unchanged . Therefore, the formula (2) can be brought into the formula (3) to obtain the output voltage of the subsequent operational amplifier as:
  • the input signal is the measured signal plus the circuit noise.
  • the output signal is the output after processing in Figure 3.
  • the input and output waveforms of the circuit are shown in Figure 8.
  • the denoising circuit eliminates the circuit noise well, and effectively suppresses the low-frequency noise brought by the circuit itself, which provides a favorable guarantee for expanding the detection capability of the low-frequency magnetic sensor.
  • the premise of this circuit is that the noise is basically unchanged before and after the switch, and it is relative to the measurement signal.
  • the change of noise before and after the switch cannot be ignored relative to the measurement signal.
  • the effect will be worse, you can further increase the switching frequency, because the noise changes in a smaller time, the amplitude of the circuit is smaller, then the effect of the circuit will be better, so if the frequency of the signal under test is not high, you can first put the high frequency The noise is filtered first to obtain better results.
  • Figure 11 shows the output power spectrum of the denoising circuit.
  • the signal peak-to-peak value is 40uV.
  • the noise peak-to-peak value reaches 400uV
  • the system magnification reaches 10 times, and the output signal of the denoising circuit can still be compared. Ideal noise processing effect.
  • the circuit eliminates 1/f noise well.
  • the present invention provides an electromagnetic surveying device having the inductive magnetic sensor as described above.
  • the invention provides an electromagnetic surveying equipment to achieve the goal of using a magnetic sensor in the frequency domain electromagnetic surveying method, which can greatly reduce the volume and weight of the magnetic sensor and bring great convenience to field construction.
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the units is only a division of logical functions.
  • there may be other divisions for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or software function unit.
  • the program may be stored in a computer-readable storage medium, and the storage medium may include: Read only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geophysics (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

一种感应式磁传感器，包括信号前置放大测量电路、反馈回路、磁芯及线圈、低噪稳零处理电路以及输出保护模块，线圈的输入端与信号前置放大测量电路电连接，信号前置放大测量电路与低噪稳零处理电路，线圈的输出端与反馈回路电连接，反馈回路和低噪稳零处理电路分别与输出保护模块电连接，通过谐振陷波器的引入，可以进一步把带宽扩展到低频，扩展磁传感器的低频特性，获得更加优良的低频磁传感器。此外，还提供了一种电磁勘探设备。

Description

一种感应式磁传感器及电磁勘探设备 技术领域
本发明涉及勘探地球物理领域，特别涉及一种感应式磁传感器及电磁勘探设备。
背景技术
感应式磁传感器(以下简称磁传感器)是基于法拉第电磁感应定律，利用线圈输出电压与穿过线圈磁通量变化量成正比的关系，通过测量线圈输出电压来间接测量磁场的装置。MT磁传感器的特征就是获得低频超低频的磁场信号，通过在高磁导率磁芯上绕制几万匝线圈，利用低噪声放大电路，采用磁通负反馈结构，把磁场转换成测量电压。
如图1所示，示出了一种感应式磁传感器的等效电路图，其中，
B为被测外磁场；
Cp为测量线圈寄生电容；
Lp为测量线圈自感；
Rp为测量线圈电阻；
Ls为反馈线圈自感；
Rs为反馈线圈电阻；
Rfb为反馈电阻；
M为反馈线圈与测量线圈之间的互感；
Np和Ns分别是测量线圈和反馈线圈的匝数；
A为放大电路的放大倍数；
vi为放大电路的输入；
vout为放大电路的输出；
e为测量线圈的感应电动势。
根据图1的电路模型，可以获得磁传感器的转换函数为：
Figure PCTCN2018119362-appb-000001
其中，μa是有效磁导率，S是磁路有效横截面积。
由于磁传感器的应用非常广泛，国内外开展感应式磁传感器研究的人员很多，在电磁法勘探领域，应用于MT方法磁传感器的典型产品有德国Metronix公司的MFS-06e和加拿大Pheonix公司的MTC-80等。在中国，研究MT磁传感器的主要有中南大学、吉林大学、以及中科院电子学研究所等单位，他们都获得了较好的应用。
虽然研究MT磁传感器的单位很多，不过这些单位或组织所采用的方法通常是在体积和重量允许的范围内确定线圈匝数后，采用提高磁芯的有效磁导率的方法来提高磁传感器的灵敏度，并通过斩波稳零放大电路来抑制低频1/f噪声效应。根据磁芯材料初始磁导率参数和退磁因子公式，需要磁芯长度达到1.0m以上，使得长径比大于40∶1，以达到足够大的有效磁导率，这给野外施工带来一定的不便。近年来，有一些单位或组织采用了一种磁通聚集器(Flux Concentrator)技术，使得较短磁芯的有效磁导率与常规细长的磁导率相当，从而实现磁场传感器的小型化。
事实上，通过增加磁芯的长径比还是增加了磁通聚集器，其有效磁导率可以有效提高，但无法扩展其低频带宽，对于磁传感器的优化有限。
为了系统稳定，线圈的谐振频率必须比测量的通带频率要高，并且通过引入磁通反馈后，压制磁传感器在谐振频率点的品质因数。这种思想本身没有问题，必须保证系统具有足够的稳定性，才是系统设计的前提。但是，这就造成了在测量极低频率的时候，由于极低频信号的灵敏度极低，无法正常拾取信号，另一方面，高频的噪声又很大，造成低频测量的信噪比非常低的窘态。
发明内容
有鉴于此，本发明实施例提供了一种感应式磁传感器及电磁勘探设备。进而扩展磁传感器的低频特性，获得更加优良的低频磁传感器。
第一方面，本发明提供一种感应式磁传感器，包括信号前置放大测量电路、反馈回路、磁芯及线圈、低噪稳零处理电路以及输出保护模块，所述线圈的输入端与所述信号前置放大测量电路电连接，所述信号前置放大测量电路与所述低噪稳零处理电路，所述线圈的输出端与所述反馈回路电连接，所述反馈回路和所述低噪稳零处理电路分别与所述输出保护模块电连接。
作为一种可选的方案，所述信号前置放大测量电路具有前置放大单元和谐振陷波器，当测量磁场频率低于100Hz时，所述前置放大单元的输入端并联设有电容，所述谐振陷波器与所述低噪稳零处理电路电连接。
作为一种可选的方案，当测量磁场频率高于100Hz时，所述信号前置放大测量电路具有前置放大单元。
作为一种可选的方案，所述线圈包括反馈线圈和测量线圈，所述反馈线圈和所述测量线圈耦合连接，所述测量线圈与所述电容并联，所述反馈线圈与所述反馈回路电连接。
作为一种可选的方案，所述信号前置放大测量电路包括两组前置放大单元和谐振陷波器，分别为第一前置放大单元、第二前置放大单元、第一谐振陷波器和第二谐振陷波器，所述第一谐振陷波器和所述第二谐振陷波器采用第一电阻连在一起输出作为输出端，所述输出端并接接地电容到参考地。
作为一种可选的方案，当测量磁场频率低于100Hz时，打开反馈回路开关。
作为一种可选的方案，所述低噪稳零处理电路采用开关稳零电路。
第二方面，本发明提供一种电磁勘探设备，具有如上述感应式磁传感器。
从以上技术方案可以看出，本发明实施例具有以下优点：
本发明提供一种感应式磁传感器及电磁勘探设备，包括信号前置放大测量电路、反馈回路、磁芯及线圈、低噪稳零处理电路以及输出保护模块，所述线圈的输入端与所述信号前置放大测量电路电连接，所述信号前置放大测量电路与所述低噪稳零处理电路，所述线圈的输出端与所述反馈回路电连接，所述反馈回路和所述低噪稳零处理电路分别与所述输出保护模块电连接，通过谐振陷波器的引入，可以进一步把带宽扩展到低频，扩展磁传感器的低频特性，获得更加优良的低频磁传感器。
附图说明
图1是现有方案中感应式磁传感器的等效电路图；
图2是本发明提供的感应式磁传感器一种实施例的电路框图；
图3是本发明提供的感应式磁传感器一种实施例中信号前置放大测量电路的结构框图；
图4是本发明提供的感应式磁传感器一种实施例中转换特性的示意图；
图5是本发明提供的感应式磁传感器一种实施例中并入电容后的示意图；
图6是本发明提供的感应式磁传感器一种实施例中去噪电路的电路图；
图7是本发明提供的感应式磁传感器一种实施例中被测信号与电路噪声的示意图；
图8是本发明提供的感应式磁传感器一种实施例中去噪电路的输入输出信号的示意图；
图9是本发明提供的感应式磁传感器一种实施例中低信噪比输入的示意图；
图10是本发明提供的感应式磁传感器一种实施例中低信噪比的电路处理结果的示意图；
图11是本发明提供的感应式磁传感器一种实施例中去噪电路输出功率谱的示意图。
具体实施方式
为了使本技术领域的人员更好地理解本发明方案，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分的实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本发明保护的范围。
结合图2所示，本发明实施例中提供一种感应式磁传感器，包括信号前置放大测量电路、反馈回路、磁芯及线圈、低噪稳零处理电路以及输出保护模块，所述线圈的输入端与所述信号前置放大测量电路电连接，所述信号前置放大测 量电路与所述低噪稳零处理电路，所述线圈的输出端与所述反馈回路电连接，所述反馈回路和所述低噪稳零处理电路分别与所述输出保护模块电连接，通过谐振陷波器的引入，可以进一步把带宽扩展到低频，扩展磁传感器的低频特性，获得更加优良的低频磁传感器。
信号前置放大测量电路具有前置放大单元和谐振陷波器，谐振陷波器用来测量线圈的谐振频率点进行陷波，当测量磁场频率低于100Hz时，所述前置放大单元的输入端并联设有电容，所述谐振陷波器与所述低噪稳零处理电路电连接。当测量磁场频率高于100Hz时，所述信号前置放大测量电路具有前置放大单元。
线圈包括反馈线圈和测量线圈，所述反馈线圈和所述测量线圈耦合连接，所述测量线圈与所述电容并联，所述反馈线圈与所述反馈回路电连接。
信号前置放大测量电路包括两组前置放大单元和谐振陷波器，分别为第一前置放大单元、第二前置放大单元、第一谐振陷波器和第二谐振陷波器，所述第一谐振陷波器和所述第二谐振陷波器采用第一电阻连在一起输出作为输出端，所述输出端并接接地电容到参考地。
本实施例中，低噪稳零处理电路采用开关稳零电路或斩波稳零式运算放大器，本领域可以灵活选择，对此不做限定。
本发明提供的感应式磁传感器，在对磁芯与优化的前提上，在测量极低频的时候，在输入端并入一个电容，由于磁通负反馈将很难影响磁传感器的磁场转换能力，并入电容后，同时打开闭环回路，所以不存在自激振荡的不稳定问题。通过陷波器的引入，可以进一步把带宽扩展到低频。为了绕开了传统斩波稳零放大电路的伪像问题，提出了一种新的稳零磁传感器处理电路，进而扩展磁传感器的低频特性，获得更加优良的低频磁传感器。
本发明提供的感应式磁传感器，以100Hz以下的磁场信号测量提供了解决方案，高于100Hz的磁场测量，需要同时去除输入电容以及谐振陷波器并闭合反馈回路即可。
如图2所示，本发明的磁传感器可以包括高磁导率磁芯、线圈、低噪声放大电路以及反馈回路，不同的是，本发明在测量线圈输入端在低频测量的时候加入了两个电容，低噪声放大电路不采用普遍使用的斩波放大器，而是专门为扩展磁传感器低频特性而设计的低噪稳零处理电路。
在前置放大器中加入电容，使得磁传感器的谐振频率向低频移动，由于谐振频率转移后，磁通负反馈将不再起作用，磁传感器只要进行开环测量就可以，不存在自激振荡的稳定性问题。同时，该电容还可以实现即抑制了高频噪声作用，又可以进一步增大放大器的增益而不饱和，使得磁传感器的频率特性通带往低频方向移动，从而实现扩频的目的。
不同于斩波放大的设计，本发明的低噪稳零技术采用前置放大，滤波以及稳零三级处理。该电路具有极好的稳零的特性，尤其对1/f噪声，失调电压，失调电压温漂，失调电流及失调电流温漂的抑制具有非常好的表现。
当测量的磁场频率低于100Hz的时候，需要在线圈到前置放大器输入端并联电容Ci，再配合后面的谐振陷波器，从而确保系统的通带进一步往低频移动，同时可以忽略反馈回路的作用；当测量的磁场频率高于100Hz的时候，需要把输入端的并联电容去掉，同时不能使用谐振陷波器，对陷波器短路，以免破坏正常测量，为了确保系统增益可以大于1而能够稳定，需要使用磁通负反馈回路。另外，测量频率高于100Hz的时候，也可以把谐振陷波器换成低通滤波器，必须保证测量频率在通带范围，这样可以减少高频噪声的影响。
信号前置放大测量电路如图3所示，信号前置放大测量电路有两个完全一 致的电路，最后两个电路通过Ro连接在一起输出，并在输出端并接一个电容Co到参考地。以其中某一个处理电路为例进行介绍，从左边开始，N是测量线圈的中间抽头，A和B分别是线圈的上下来个抽头，被送入双输入单输出的前置放大器，后面接入一个谐振陷波器，这个谐振陷波器主要是为了进一步扩展通带往低频移动，加强低频成分。谐振陷波波后送到电路的去噪核心电路，该电路通过开关控制电路工作在两种模式，图3中的上下两个电路分别展示这两种状态：一种是跟踪噪声，并把噪声信号存放在电容C上，如图3的下半部分；另一种是把输入信号减去存放在电容C上的电路噪声信号，如图3的下半部分。
图3中的上下两部分电路是互补工作的，当某一电路工作在噪声追踪状态时，另一个电路工作在测量状态，并输出测量信号，并通过Ro与电容Co滤波后作为输出信号。Ro与Co的选取必须确保截止频率高于测量通带上限频率。
本发明可以实现频率域电磁法勘探方法共同用一根磁传感器的目标，可以大大减小磁传感器的体积与重量，给野外施工带来极大的方便。
本发明实施例中提供了一种感应式磁传感器的应用场景，加以说明。
在实验室内具有一个谐振频率达20kHz的磁传感器，可应用于可控源音频打的电磁(CSAMT)探测，其测量线圈的自感为0.3459H，寄生电容为170pF，测量线圈电阻为1934Ω，线圈等效面积为S＝112.903mm2，测量线圈的匝数为10000匝，反馈电阻Rf＝1kΩ，反馈线圈匝数为35匝，有效磁导率为705，放大倍数为1，则磁传感器有无带反馈磁通的转换关系如图4所示。
图4示出了磁传感器的转换特性，可以看出，磁传感器的谐振频率为20kHz，通过加入闭环磁通负反馈后，谐振点处的品质因数大幅度下降，从而 系统可以稳定的工作。当测量频率为小于100Hz的低频时，显然这么高的谐振频率不利于测量，在前置放大器输入端并入2uF电容后，磁传感器的谐振点往低频移动到170Hz，为了使系统通带进一步往低频扩展，并提高系统增益，在新的谐振点处加入陷波器。并入电容后，不同条件下的磁场转换特性如图5所示。
从图5可以看出，并入电容后的磁传感器转换特性，谐振转移到低频的时候，闭环基本上不起作用，有无磁通负反馈对磁传感器已经没有作用，所以并入电容后，可以忽略磁通负反馈的作用。如果不引入陷波器，那么系统将在170Hz附近具有较高的转换性能，从而影响低频测量，引入陷波器后，迫使磁传感器在170Hz转换性能往下压，使得磁传感器的频带进一步往低频扩展，磁传感器可以通过进一步提高系统增益来获得低频信号而不进入饱和。
关于去噪的问题，截取其中的一半电路进行说明，如图6所示，去噪电路当SW1闭合的时候，前置放大输入为0，前置放大器输出是其的噪声电压vnoise1，把前置放大的噪声电压送给下一级同相输入电压跟随器，采样电容C上获得了前置放大电路以及后级运放的总噪声。设后级运放的噪声电压为vnoise2，电容上的电压为：
v c＝v noise1+v noise2    (2)；
当SW1打开的时候，由于电容上保存了前置放大电路以及本级运放的总噪声，被测信号vi输入后，送给后级的电压输出为：
Figure PCTCN2018119362-appb-000002
由于电路主要是1/f噪声，失调电压，失调电压温漂，失调电流，失调电流温漂，这些噪声的频率都很低，在足够高的开关频率条件下，开关的前后， 认为噪声不变。于是可以把公式(2)带入公式(3)从而获得后级运放输出电压为：
Figure PCTCN2018119362-appb-000003
可见，输出已经把噪声消除了，保留了被测信号。
有一个200uV的被测50Hz正弦信号，电路中有一个峰峰值达到400uV的1/f噪声，如图7所示，被测信号与电路噪声。
利用图3所示的电路进行处理，输入信号为被测信号与电路噪声相加，输出信号为通过图3处理后的输出，电路的输入输出波形如图8所示，去噪电路的输入输出信号。
从图8可以看出，去噪电路很好地消除了电路噪声，对电路本身带来的低频噪声实现了有效抑制，这为扩展低频磁传感器的探测能力提供了有利保证。
当然，这个电路的前提是在开关前后，噪声基本不变，是相对测量信号而言的，当测量信号很低，噪声在开关前后的变化相对于测量信号而言不能忽略，那么该处理电路的效果会变差，可以通过进一步提高开关频率，由于噪声在更小的时间内变化幅度更小，那么电路的效果会更好，所以该被测信号频率不高的条件下，可以先把高频噪声先滤除，从而获得更好的效果。
如果测量信号还是50Hz，输入信噪比更低，输入噪声不变，测量信号为减小10倍为20uV，如图9所示低信噪比输入：
系统的放大倍数调整到10倍，获得输入输出波形对比如图10所示，低信噪比的电路处理结果：
测量时间为0.16s输出信号(约8个测量信号周期)的功率谱如图11所示：
图11中示出了去噪电路输出功率谱从图11可以看出，信号峰峰值为40uV， 噪声峰峰值达到400uV的时候，系统放大倍数达到10倍，去噪电路的输出信号仍然可以获得比较理想的噪声处理效果。而且电路很好地消除了1/f噪声。
相应地，本发明提供一种电磁勘探设备，具有如上述感应式磁传感器。
本发明提供一种电磁勘探设备，以实现频率域电磁法勘探方法共同用一根磁传感器的目标，可以大大减小磁传感器的体积与重量，给野外施工带来极大的方便。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功 能单元的形式实现。
本领域普通技术人员可以理解上述实施例的各种方法中的全部或部分步骤是可以通过程序来指令相关的硬件来完成，该程序可以存储于一计算机可读存储介质中，存储介质可以包括：只读存储器(ROM，Read Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁盘或光盘等。
以上对本发明所提供的一种感应式磁传感器及电磁勘探设备进行了详细介绍，对于本领域的一般技术人员，依据本发明实施例的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本发明的限制。

Claims (8)

  1. 一种感应式磁传感器，其特征在于，包括信号前置放大测量电路、反馈回路、磁芯及线圈、低噪稳零处理电路以及输出保护模块，所述线圈的输入端与所述信号前置放大测量电路电连接，所述信号前置放大测量电路与所述低噪稳零处理电路，所述线圈的输出端与所述反馈回路电连接，所述反馈回路和所述低噪稳零处理电路分别与所述输出保护模块电连接。
  2. 根据权利要求1所述的感应式磁传感器，其特征在于，所述信号前置放大测量电路具有前置放大单元和谐振陷波器，当测量磁场频率低于100Hz时，所述前置放大单元的输入端并联设有电容，所述谐振陷波器与所述低噪稳零处理电路电连接。
  3. 根据权利要求1所述的感应式磁传感器，其特征在于，当测量磁场频率高于100Hz时，所述信号前置放大测量电路具有前置放大单元。
  4. 根据权利要求1所述的感应式磁传感器，其特征在于，所述线圈包括反馈线圈和测量线圈，所述反馈线圈和所述测量线圈耦合连接，所述测量线圈与所述电容并联，所述反馈线圈与所述反馈回路电连接。
  5. 根据权利要求2所述的感应式磁传感器，其特征在于，所述信号前置放大测量电路包括两组前置放大单元和谐振陷波器，分别为第一前置放大单元、第二前置放大单元、第一谐振陷波器和第二谐振陷波器，所述第一谐振陷波器和所述第二谐振陷波器采用第一电阻连在一起输出作为输出端，所述输出端并接接地电容到参考地。
  6. 根据权利要求2所述的感应式磁传感器，其特征在于，当测量磁场频率低于100Hz时，打开反馈回路开关。
  7. 根据权利要求1所述的感应式磁传感器，其特征在于，所述低噪稳零处理电路采用开关稳零电路。
  8. 一种电磁勘探设备，其特征在于，具有如权利要求1至7中任一项所述感应式磁传感器。
PCT/CN2018/119362 2018-12-05 2018-12-05 一种感应式磁传感器及电磁勘探设备 WO2020113467A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2018/119362 WO2020113467A1 (zh) 2018-12-05 2018-12-05 一种感应式磁传感器及电磁勘探设备
US17/115,808 US11914092B2 (en) 2018-12-05 2020-12-09 Inductive magnetic sensor and electromagnetic prospecting equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2018/119362 WO2020113467A1 (zh) 2018-12-05 2018-12-05 一种感应式磁传感器及电磁勘探设备

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/115,808 Continuation US11914092B2 (en) 2018-12-05 2020-12-09 Inductive magnetic sensor and electromagnetic prospecting equipment

Publications (1)

Publication Number Publication Date
WO2020113467A1 true WO2020113467A1 (zh) 2020-06-11

Family

ID=70974396

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/119362 WO2020113467A1 (zh) 2018-12-05 2018-12-05 一种感应式磁传感器及电磁勘探设备

Country Status (2)

Country Link
US (1) US11914092B2 (zh)
WO (1) WO2020113467A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108594315A (zh) * 2018-04-20 2018-09-28 江苏省地震局 基于感应式磁传感器的地震电磁扰动观测系统及观测方法
CN114296015A (zh) * 2021-12-20 2022-04-08 宁波泰丰源电气有限公司 一种传感器电磁感应组件

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0943328A (ja) * 1995-07-28 1997-02-14 Sharp Corp 超電導磁気検出装置
CN102147482A (zh) * 2010-02-05 2011-08-10 朱万华 一种用于浅层csamt方法的感应式磁传感器的发明
CN102854535A (zh) * 2012-08-24 2013-01-02 中国船舶重工集团公司第七二二研究所 一种宽带磁性传感器
CN106443508A (zh) * 2016-09-19 2017-02-22 中国电子科技集团公司第二十研究所 一种低噪声高灵敏度感应式磁传感器
CN106483480A (zh) * 2016-09-26 2017-03-08 中国人民解放军国防科学技术大学 基于gmi效应的单探头生物磁场探测方法、电路及传感器
CN108802832A (zh) * 2018-06-15 2018-11-13 中国科学院地质与地球物理研究所 一种用于大地电磁探测的磁传感器

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6417666B1 (en) * 1991-03-01 2002-07-09 Digital Control, Inc. Boring tool tracking system and method using magnetic locating signal and wire-in-pipe data
JP5492389B2 (ja) * 2008-06-16 2014-05-14 独立行政法人石油天然ガス・金属鉱物資源機構 磁場センサー装置
US9692329B2 (en) * 2014-08-08 2017-06-27 Johnson Electric S.A. Magnetic sensor and an integrated circuit
US10324215B2 (en) * 2014-12-30 2019-06-18 Witricity Corporation Systems, methods, and apparatus for detecting ferromagnetic foreign objects in a predetermined space

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0943328A (ja) * 1995-07-28 1997-02-14 Sharp Corp 超電導磁気検出装置
CN102147482A (zh) * 2010-02-05 2011-08-10 朱万华 一种用于浅层csamt方法的感应式磁传感器的发明
CN102854535A (zh) * 2012-08-24 2013-01-02 中国船舶重工集团公司第七二二研究所 一种宽带磁性传感器
CN106443508A (zh) * 2016-09-19 2017-02-22 中国电子科技集团公司第二十研究所 一种低噪声高灵敏度感应式磁传感器
CN106483480A (zh) * 2016-09-26 2017-03-08 中国人民解放军国防科学技术大学 基于gmi效应的单探头生物磁场探测方法、电路及传感器
CN108802832A (zh) * 2018-06-15 2018-11-13 中国科学院地质与地球物理研究所 一种用于大地电磁探测的磁传感器

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108594315A (zh) * 2018-04-20 2018-09-28 江苏省地震局 基于感应式磁传感器的地震电磁扰动观测系统及观测方法
CN114296015A (zh) * 2021-12-20 2022-04-08 宁波泰丰源电气有限公司 一种传感器电磁感应组件
CN114296015B (zh) * 2021-12-20 2023-09-26 宁波泰丰源电气有限公司 一种传感器电磁感应组件

Also Published As

Publication number Publication date
US20210088689A1 (en) 2021-03-25
US11914092B2 (en) 2024-02-27

Similar Documents

Publication Publication Date Title
CN201541238U (zh) 一种能降低低频噪声的磁共振成像mri系统前置放大器
WO2020113467A1 (zh) 一种感应式磁传感器及电磁勘探设备
CN109150123A (zh) 一种高增益的微弱信号前置放大电路
CN104515931B (zh) 一种基于磁调制的直流漏电流传感器
CN203759090U (zh) 轨道交通牵引数据采集系统的电流采样电路
CN109407157B (zh) 一种感应式磁传感器及电磁勘探设备
CN109950696A (zh) 整流天线
CN107589296A (zh) 高压回路的信号采集装置、检测器、电池装置和运载工具
CN210639247U (zh) 基于电源隔离的微弱电压信号检测系统
CN205786850U (zh) 一种电网谐波信号采集预处理电路
CN207336632U (zh) 一种射频电源功率检测电路
US10338170B2 (en) Pre-amplifier for magnetic resonance imaging radio-frequency coil
CN217445324U (zh) 一种微弱电信号低噪声前置放大电路
CN111200447A (zh) 一种特定频率的钻孔电磁波接收天线的前放电路
CN221123301U (zh) 一种电涡流传感器
CN117232666A (zh) 一种基于单光子探测器的雪崩信号提取系统及方法
CN210807239U (zh) 一种特定频率的钻孔电磁波接收天线的前放电路
CN221078848U (zh) 一种开关柜tev局放信号检测电路
CN109407156B (zh) 全频段磁传感器
CN118487487B (zh) 一种基于pcb型罗氏线圈的有源emi滤波器及其设计方法
CN108983297B (zh) 一种地面电磁信号检测电路
CN210222127U (zh) 一种闪电电场变化传感器信号处理电路
Wang et al. Frequency response analysis of a Rogowski coil transducer for railgun pulse current measurement
CN220173207U (zh) 一种高速高增益跨阻放大模块
CN116559513B (zh) 一种积分电路及电流传感器

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18942251

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18942251

Country of ref document: EP

Kind code of ref document: A1