CN106643826B - The detection circuit and detection method of LC resonance formula sensor - Google Patents
The detection circuit and detection method of LC resonance formula sensor Download PDFInfo
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- CN106643826B CN106643826B CN201610959765.7A CN201610959765A CN106643826B CN 106643826 B CN106643826 B CN 106643826B CN 201610959765 A CN201610959765 A CN 201610959765A CN 106643826 B CN106643826 B CN 106643826B
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- formula sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
Abstract
The present invention provides a kind of LC resonance formula sensor detection circuits, it include: SoPC system, impulse generator, transmitting coil, read coil, analog-digital converter based on FPGA, the emitted coil of SoPC system control impulse generator based on FPGA generates pumping signal, the energy-sensitive that LC resonance formula sensor absorbs pumping signal generates deamplification, it is received by read coil, analog-digital converter sampling, SoPC system based on FPGA calculates LC resonance formula sensor output signal spectrum by DFT, completes the detection of resonance frequency.The present invention also provides a kind of LC resonance formula sensor detection circuit detection methods, first acquisition LC resonance formula sensor output signal spectrum, then obtain the resonance frequency of LC resonance formula sensor by peak detection algorithm.The present invention reduces the interference of LC resonance formula sensor detection circuit complexity and pumping signal to sensor signal, improves measuring speed and portability.
Description
Technical field
The present invention relates to the detection circuits and detection side of sensor detection field more particularly to a kind of LC resonance formula sensor
Method.
Background technique
The core component of LC resonance formula sensor is the LC resonance circuit being composed in series by inductance, capacitor, wherein electricity
Sense or capacitor are measured (such as: pressure, temperature, chemical quantity etc.) as sensing unit impression, are converted into LC resonance for measured
The resonance frequency in circuit.To obtain LC resonance formula sensor signal, it is also necessary to which detection circuit is matching.Fig. 1 is the prior art
In common LC resonance formula sensor detection circuit, testing principle is based primarily upon impedance variation method, i.e., using sensor and reads
The frequency characteristic (amplitude versus frequency, Phase-Frequency, real part-frequency, imaginary part-frequency) of the equivalent input impedance of line taking circle is surveyed indirectly
The resonance frequency of quantity sensor.
Since the sensing unit of LC resonance formula sensor is formed using inductance and capacitor, make it have that structure is simple, size
Advantage small, manufacturing cost is lower, simultaneously because its have can wireless measurement characteristic, thus especially suitable for object under enclosed environment
The detection of signal under the contactless monitoring of reason amount, such as inside of human body pressure monitoring, industrial high temperature environment and closed environment
Deng.
According to the working principle of LC resonance formula sensor, usually read using the measurement of high-precision Network Analyzer in laboratory
The impedance phase of line taking circle is composed, and detects the resonance frequency of sensor from impedance phase spectrum, but the volume of Network Analyzer it is big,
Equipment is heavy, at high cost, since Network Analyzer makes it difficult to be applied to reality there are the limitation of above-mentioned volume, cost etc.
In detection.The closed-loop detection circuit that M.Nowak et al. is proposed is the position measurement for being zero by locking read coil impedance phase
The resonance frequency of sensor；The detection circuit based on voltage controlled oscillator (VCO) that J.Coosemans et al. is proposed, passes through electricity
The frequency characteristic of voltage-controlled VCO output swept-frequency signal measurement read coil input impedance processed, to realize sensor resonant frequency
Measurement；However, for the LC resonance formula sensor of high resonant frequency, using closed loop circuit detection method, it is difficult to realize stable
Closed loop；And the swept-frequency signal quality (amplitude coincidence, frequency interval etc.) for using the detection method of VCO to generate is poor, and detects
Speed is slower.
Summary of the invention
(1) technical problems to be solved
In view of above-mentioned technical problem, the present invention provides the detection circuit and detection method of a kind of LC resonance formula sensor,
The interference of LC resonance formula sensor detection circuit complexity and pumping signal to sensor signal is reduced, measuring speed is improved
And portability.
(2) technical solution
According to an aspect of the invention, there is provided a kind of LC resonance formula sensor detection circuit, which is characterized in that packet
It includes: the SoPC system based on FPGA, impulse generator, transmitting coil, read coil, analog-digital converter, in which:
The SoPC system based on FPGA is connect with the impulse generator, is controlled for sending to the impulse generator
System order；
The impulse generator is connect with the transmitting coil, for emitting pumping signal by the transmitting coil；
The transmitting coil motivates LC resonance formula sensor, its induction is made to generate decaying letter for emitting pumping signal
Number；
The read coil is connect with the analog-digital converter, for receiving the decaying of LC resonance formula sensor generation
Signal, and it is sent to analog-digital converter；
SoPC system of the analog-digital converter with the read coil and based on FPGA is connect, and is used for the read line
The deamplification for enclosing the LC resonance formula sensor received is converted to digital signal, and is sent to the SoPC based on FPGA
System.
According to another aspect of the present invention, a kind of LC resonance formula sensor detection circuit detection method, feature are provided
It is, comprising:
The emitted coil of SoPC system control impulse generator based on FPGA generates pumping signal；
Induction generates deamplification after the energy of LC resonance formula sensor absorption pumping signal；
The deamplification is received through read coil, after analog-digital converter sampling, is converted to digital signal, and be sent to base
In the SoPC system of FPGA；
LC resonance formula sensor output signal frequency is calculated through DFT to the digital signal in SoPC system based on FPGA
Spectrum, then spectrum peak place frequency, the as resonance frequency of LC resonance formula sensor are calculated by peak detection algorithm.
(3) beneficial effect
It can be seen from the above technical proposal that the detection circuit and detection method of LC resonance formula sensor of the present invention at least have
There is one of following beneficial effect:
(1) wireless measurement that LC resonance formula sensor is realized using pulse excitation mode, reduces the LC of high resonant frequency
The realization difficulty of resonant transducer detection circuit, improves detection speed；
(2) read coil is connected differential received modes using double inductance reverse phases, reduces excited by rectangular pulse signal and outer
It is interfered caused by the useful signal that boundary's electromagnetic noise generates LC resonance formula sensor, improves the letter that read coil receives signal
It makes an uproar ratio；
(3) system cost is reduced using the embedded system that FPGA is realized, reduces system bulk, improves system
Portability.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of LC resonance formula sensor detection circuit in the prior art；
Fig. 2 is detection circuit operation principle schematic diagram of the present invention；
Fig. 3 is that transmitting coil of the present invention, LC resonance formula sensor and read coil constitute mutual inductice coupled circuit
And its equivalent circuit diagram；
Fig. 4 is LC resonance formula sensor output signal spectrum figure of the invention；
Fig. 5 is LC resonance formula sensor detection circuit detection method flow chart of the invention.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference
Attached drawing, the present invention is described in more detail.
In a specific embodiment of the present invention, a kind of LC resonance formula sensor detection circuit is provided.Fig. 2 is of the invention
The structural schematic diagram of LC resonance formula sensor detection circuit in embodiment.As shown in Fig. 2, LC resonance formula sensor detection of the present invention
Circuit includes: SoPC system based on FPGA, impulse generator, transmitting coil, read coil, analog-digital converter and upper
Machine, in which:
The SoPC system based on FPGA is connect with the impulse generator, analog-digital converter and host computer, for controlling
The impulse generator is made, the digital signal that the analog-digital converter obtains is handled, operation obtains the humorous of LC resonance formula sensor
Vibration frequency, and it is uploaded to the host computer, and execute the control command of the host computer；
The SoPC system based on FPGA includes frequency spectrum computing module (such as frequency spectrum calculates IP) and control module (example
Such as the soft core of MicroBlaze).Wherein, the frequency spectrum computing module is used for the attenuated sinusoidal signal generated to LC resonance formula sensor
The digital signal obtained after analog-to-digital conversion carries out real-time DFT (discrete Fourier transform) operation, and LC resonance formula biography is calculated
Sensor signal frequency spectrum；The control module for realizing detection circuit control function and data processing function, by described
The frequency spectrum that frequency spectrum computing module obtains carries out peak detection, finds the corresponding Frequency point of spectrum peak, and as LC resonance formula senses
The resonance frequency of device, and the communication with the host computer progress control command and digital command；
The impulse generator is connect with the SoPC system based on FPGA and transmitting coil, for receiving described be based on
The control command of the SoPC system of FPGA, and excited by rectangular pulse signal is emitted by the transmitting coil；
The transmitting coil is connect with the impulse generator, for emitting excited by rectangular pulse signal, motivates LC resonance
Formula sensor makes its induction generate attenuated sinusoidal signal；
The read coil is connect with the analog-digital converter, for receiving the attenuated sinusoidal of LC resonance formula sensor generation
Signal, and it is sent to analog-digital converter；
Transmitting coil, LC resonance formula sensor and read coil of the invention constitutes mutual inductice coupled circuit as shown in Figure 3
And its equivalent circuit.The read coil is connected two inductance reverse phases using double inductance reverse phases series connection differential received modes
Differential input structure is formed, LC resonance formula sensor is generated reducing excited by rectangular pulse signal and external electromagnetic noise
It is interfered caused by useful signal, improves the signal-to-noise ratio that read coil receives signal.For this purpose, the read coil
Two inductance should ensure that polar opposite outer other parameters are identical, so that the mutual inductance algebraical sum between two inductance of read coil
It is zero；The transmitting coil is full symmetric about two inductance of read coil, so that transmitting coil and the double inductance of read coil
Between mutual induction amount be equal or approximately equal, the algebraical sum of two mutual inductances is zero；
In the circuit, UI、UOThe respectively input of the mutual inductice coupled circuit, output voltage, IT、IS、IRRespectively flow through
The electric current of transmitting coil, LC resonance formula sensor and read coil, LT、RTThe respectively inductance and its series equivalent of transmitting coil
Resistance, CS、LS、RSThe respectively sensitization capacitance of LC resonance formula sensor, fixed inductance and its equivalent series resistance, LR1、RR1With
LR2、RR2The concatenated inductance of two reverse phases and its series equivalent resistance, M respectively in read coilTS、MSR1、MSR2Respectively emission lines
Mutual inductance, sensor and the read coil inductance L of circle and sensorR1Mutual inductance and sensor and read coil inductance LR2Mutual inductance.
Wherein: the electric current for flowing through transmitting coil, LC resonance formula sensor and read coil is respectively as follows:
IT(ω)=HT(ω)[UI(ω)-kT(ω)IS(ω)] (1)
IS(ω)=HS(ω)[kT(ω)IT(ω)+kS(ω)IR(ω)] (2)
IR(ω)=HR(ω)kS(ω)IS(ω) (3)
(1)-(3) H in formulaT、HS、HRThe respectively transmitting letter of transmitting coil, LC resonance formula sensor and read coil
Number, kT、kS、kRIt is proportionality coefficient, expression formula is as follows:
kT(ω)=j ω MTS (7)
kS(ω)=j ω (MSR1-MSR2) (8)
kR(ω)=RR1+RR2 (9)
Simultaneous (1)-(3) formula, and substitute into (4)-(9) formula and can obtain IRExpression formula.
The mutual inductice coupled circuit output voltage are as follows:
UO(ω)=kR(ω)IR(ω) (10)
The mutual inductice coupled circuit transmission function are as follows:
The input signal of the mutual inductice coupled circuit is excited by rectangular pulse signal, Fourier transformation are as follows:
Wherein, E is rectangular pulse amplitude, and τ is rectangular pulse width, and ω is angular frequency.
The Fourier transformation of the output voltage signal of the mutual inductice coupled circuit are as follows:
Y (ω)=H (ω) X (ω) (13)
Output signal spectrum is as shown in figure 4, spectrum peak | Y (ω) |maxCorresponding frequency is LC resonance formula sensor
Resonance frequency fres。
Finally, being back-calculated to obtain to the measured value x functional relation to measured value and resonance frequency that can be obtained by calibration experiment:
X=kfres+b (14)
Wherein, k and b be calibration experiment obtain to the fitting coefficient in measured value and the functional relation of resonance frequency.
The analog-digital converter is connect with the SoPC system based on FPGA and read coil, is used for the read line
The analog signal for enclosing the LC resonance formula sensor received is converted to digital signal, and is sent to the SoPC based on FPGA
System；
The host computer is connect with the SoPC system based on FPGA, for controlling the SoPC system based on FPGA
System receives the SoPC system operations based on FPGA and obtains the resonance frequency of LC resonance formula sensor, by resonance frequency with
Functional relation between being measured extrapolates tested magnitude, and by tested magnitude real-time display in host computer.
LC resonance formula sensor detection circuit detection method as shown in Figure 5, detection method includes the following steps:
Step 1: the SoPC system based on FPGA receives the control signal of host computer, start to LC resonance formula sensor into
Row detection；
Step 2: the emitted coil of SoPC system control impulse generator based on FPGA generates excited by rectangular pulse signal；
Induction generates attenuated sinusoidal signal after the energy of step 3:LC resonant transducer absorption excited by rectangular pulse signal；
Step 4: the attenuated sinusoidal signal is received through read coil, after analog-digital converter sampling, is converted to digital signal,
And it send to the SoPC system based on FPGA；
Step 5: output signal spectrum is calculated through DFT to the digital signal in the SoPC system based on FPGA, then passes through
Peak detection algorithm calculates frequency where spectrum peak, the as resonance frequency of LC resonance formula sensor；
The detection method can further comprise also step 6: the resonance frequency that above-mentioned steps 5 obtain be uploaded to upper
Machine, functional relation of the host computer by resonance frequency and between being measured, extrapolates tested magnitude, finally that measured value is aobvious in real time
It is shown in host computer.
So far, attached drawing is had been combined the embodiment of the present invention is described in detail.According to above description, art technology
Personnel should have clear understanding to LC resonance formula sensor detection circuit of the present invention and detection method.
It should be noted that in attached drawing or specification text, the implementation for not being painted or describing is affiliated technology
Form known to a person of ordinary skill in the art, is not described in detail in field.In addition, the above-mentioned definition to each element and method is simultaneously
It is not limited only to various specific structures, shape or the mode mentioned in embodiment, those of ordinary skill in the art can carry out letter to it
It singly changes or replaces.
Certainly, according to actual needs, the detection circuit and detection method of LC resonance formula sensor of the present invention also include other
Structure and step, due to unrelated with innovation of the invention, details are not described herein again.
Particular embodiments described above has carried out further in detail the purpose of the present invention, technical scheme and beneficial effects
It describes in detail bright, it should be understood that the above is only a specific embodiment of the present invention, is not intended to restrict the invention, it is all
Within the spirit and principles in the present invention, any modification, equivalent substitution, improvement and etc. done should be included in guarantor of the invention
Within the scope of shield.
Claims (10)
1. a kind of LC resonance formula sensor detection circuit characterized by comprising the SoPC system based on FPGA, pulse generation
Device, transmitting coil, read coil, analog-digital converter, in which:
The SoPC system based on FPGA is connect with the impulse generator, for sending control life to the impulse generator
It enables；
The impulse generator is connect with the transmitting coil, for emitting pumping signal by the transmitting coil；
The transmitting coil motivates LC resonance formula sensor, its induction is made to generate deamplification for emitting pumping signal；
The read coil is connect with the analog-digital converter, for receiving the decaying letter of LC resonance formula sensor generation
Number, and it is sent to analog-digital converter；
SoPC system of the analog-digital converter with the read coil and based on FPGA is connect, for connecing the read coil
The deamplification of the LC resonance formula sensor received is converted to digital signal, and is sent to the SoPC system based on FPGA
System, the SoPC system operations based on FPGA obtain the resonance frequency of the LC resonance formula sensor.
2. LC resonance formula sensor detection circuit according to claim 1, which is characterized in that the transmitting coil transmitting
Pumping signal is excited by rectangular pulse signal.
3. LC resonance formula sensor detection circuit according to claim 2, which is characterized in that the LC resonance formula sensor
The deamplification that induction generates is attenuated sinusoidal signal.
4. LC resonance formula sensor detection circuit according to claim 1, which is characterized in that it further include host computer, it is described
Host computer is connect with the SoPC system based on FPGA, for controlling the SoPC system based on FPGA, receives the base
In the resonance frequency for the LC resonance formula sensor that the SoPC system operations of FPGA obtain, by resonance frequency and between being measured
Functional relation extrapolate tested magnitude, and by tested magnitude real-time display in host computer.
5. LC resonance formula sensor detection circuit according to claim 4, which is characterized in that the SoPC based on FPGA
System includes frequency spectrum computing module and control module, and the frequency spectrum computing module is for declining to LC resonance formula sensor generation
Subtract the digital signal that sinusoidal signal obtains after analog-to-digital conversion and carry out real-time DFT (discrete Fourier transform) operation, is calculated
LC resonance formula sensor output signal spectrum；The control module for realizing detection circuit control function and data processing function
Can, peak detection is carried out by the frequency spectrum obtained to the frequency spectrum computing module, finds the corresponding Frequency point of spectrum peak, as
The resonance frequency of LC resonance formula sensor, and the communication with the host computer progress control command and digital command.
6. LC resonance formula sensor detection circuit according to claim 5, which is characterized in that tested magnitude x can pass through mark
The obtained functional relation to measured value and resonance frequency is tested calmly to obtain:
X=kfres+ b,
Wherein, k and b be calibration experiment obtain to the fitting coefficient in measured value and the functional relation of resonance frequency, fresFor LC
The resonance frequency of resonant transducer.
7. LC resonance formula sensor detection circuit according to claim 1, which is characterized in that the read coil is using double
Inductance reverse phase series connection differential received mode.
8. LC resonance formula sensor detection circuit according to claim 4, which is characterized in that two of the read coil
The polar opposite outer other parameters of inductance are identical, so that the mutual inductance algebraical sum between two inductance of read coil is zero.
9. LC resonance formula sensor detection circuit according to claim 4, which is characterized in that the transmitting coil is about reading
Two inductance of line taking circle are full symmetric, so that the mutual induction amount between transmitting coil and the double inductance of read coil is equal, two mutual inductances
Algebraical sum is zero.
10. a kind of LC resonance formula sensor detection circuit detection method characterized by comprising
The emitted coil of SoPC system control impulse generator based on FPGA generates pumping signal；
Induction generates deamplification after the energy of LC resonance formula sensor absorption pumping signal；
The deamplification is received through read coil, after analog-digital converter sampling, is converted to digital signal, and be sent to and be based on
The SoPC system of FPGA；
LC resonance formula sensor output signal spectrum is calculated through DFT to the digital signal in SoPC system based on FPGA, then
The resonance frequency of the LC resonance formula sensor is obtained by peak detection algorithm.
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| CN108490423A (en) * | 2018-03-26 | 2018-09-04 | 王智华 | Wireless location system, detection device and building structure |
| CN109557168B (en) * | 2018-11-27 | 2023-01-24 | 河南师范大学 | Anti-interference high-sensitivity gas-liquid two-phase flow phase content detection method |
| CN111638382A (en) * | 2020-05-14 | 2020-09-08 | 东南大学 | LC formula rotational speed sensor based on synchronous detection |
| CN111829559B (en) * | 2020-06-24 | 2022-07-08 | 东南大学 | Method for realizing multi-parameter measurement of PT symmetrical LC passive wireless sensing system |
| CN112179959B (en) * | 2020-11-02 | 2022-10-21 | 国家电网有限公司 | High-voltage cable insulating layer damage detection device and signal processing method |
| CN112504104B (en) * | 2020-11-20 | 2022-09-09 | 苏州纳芯微电子股份有限公司 | Position sensing circuit based on inductance principle, sensor and position measuring method |
| CN112577414B (en) * | 2020-12-18 | 2022-08-02 | 上海奥蓝迪物联网科技有限公司 | Pulse type LC oscillation induction type angle sensor and angle position measuring method |
| CN112713822B (en) * | 2020-12-29 | 2023-11-03 | 同济大学 | High-frequency modulation motor position detection device |
| CN112781758B (en) * | 2020-12-30 | 2022-03-08 | 北京航空航天大学 | Measurement device and measurement method for correcting force |
| CN113640374A (en) * | 2021-08-05 | 2021-11-12 | 四川德源管道科技股份有限公司 | Eddy current detection system for nondestructive testing of pipeline |
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