CN114166797A - Gas concentration measuring system based on wavelength modulation spectrum technology - Google Patents
Gas concentration measuring system based on wavelength modulation spectrum technology Download PDFInfo
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
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- G01J2003/4332—Modulation spectrometry; Derivative spectrometry frequency-modulated
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Abstract
The invention discloses a gas concentration measuring system based on a wavelength modulation spectrum technology, which comprises a diode laser, a laser controller, a function waveform generator, a pressure gauge, a vacuum pump, a gas multi-channel pool, a focusing lens, a photoelectric detector, a lock-in amplifier, a collecting card and the like, wherein: the diode laser is used as a light source, the current and the temperature are controlled by a laser controller, output light sequentially passes through a gas multi-pass cell, a photoelectric detector and a lock-in amplifier, and a signal demodulated by the lock-in amplifier is input into an acquisition card; the function waveform generator generates sawtooth waves and high-frequency sine waves output by the phase-locked amplifier, and the sawtooth waves and the high-frequency sine waves are input to the laser controller through superposition of the adder; and the signal demodulated by the phase-locked amplifier is input into a collection card and is displayed on a computer through LabVIEW. And establishing a second harmonic signal peak value and concentration fitting curve to quickly invert the concentration. The invention has high measurement precision and simple and convenient test process, and provides an effective method for accurately and quickly detecting trace gas for engineering application.
Description
The study was funded by the university of Anhui Engineers Innovation fund project.
Technical Field
The invention relates to the technical field of spectral measurement, in particular to a measuring system which extracts a second harmonic signal based on a wavelength modulation spectrum technology and can convert the second harmonic signal into the concentration of gas to be measured by calibrating the amplitude of the second harmonic.
Background
The tunable laser absorption spectrum technology can realize in-situ on-line measurement of parameters such as component concentration, temperature, pressure, speed and the like by utilizing the laser absorption characteristics of components in the gas to be measured. Compared with other technologies, the laser absorption spectrum technology has the advantages of accurate measurement, high response speed, non-invasive induction and the like, and has wide application prospect in the field of atmospheric environment detection. The tunable laser absorption spectroscopy technology is mainly divided into a direct absorption spectroscopy technology and a wavelength modulation spectroscopy technology.
The working principle of the direct absorption spectrum technology is that a certain scanning current is injected into a laser, the laser wave band emitted by the laser is driven to completely cover the wave band of a gas absorption peak, the laser passes through an absorption path containing gas to be detected and is absorbed by the gas at a specific position, an absorbed optical signal is converted into an electric signal through a photoelectric detector, and the characteristics of the absorption peak are provided by means of baseline fitting and the like. The direct absorption spectrum technology system is simple and easy to realize, but the measuring result is easily influenced by the emergent light intensity of the laser and the like, and the stability of the measuring result is poor. Therefore, the stability and the measurement accuracy of the system are often improved by the wavelength modulation spectrum technology.
The working principle of the wavelength modulation spectrum technology is that a high-frequency sinusoidal signal with the frequency f is modulated on the scanning current of a laser, laser emitted by the laser is absorbed by gas to be measured, an optical signal is converted into an electric signal by a photoelectric detector, a phase-locked amplifier carries out phase-sensitive detection processing by utilizing the mutual irrelevance between an input signal and a noise signal, the electric signal is demodulated by a same-frequency (1f) or frequency-doubling (nf) signal, a complete useful signal is extracted from noise, and the concentration of the gas to be measured can be obtained by the relation between the amplitude of a harmonic signal and the concentration of the gas to be measured. The value of the frequency f is dozens of kHz to hundreds of kHz, and the frequency and the amplitude of the high-frequency sinusoidal modulation signal are changed, so that the optical noise in the direct absorption spectrum technology can be effectively reduced. Meanwhile, the wavelength modulation spectrum technology moves the information to be detected to a high-frequency wave band, so that 1/f low-frequency noise in the system is effectively inhibited, and higher detection precision is obtained.
Compared with the direct absorption spectrum technology, the wavelength modulation spectrum technology has more complicated measurement system and data processing process, but various noises existing in measurement are reduced due to the fact that the detection frequency is shifted to a high frequency position, and the method is suitable for the condition of low gas concentration.
Disclosure of Invention
The invention aims to solve the technical problem of providing a gas concentration measuring system based on a wavelength modulation spectrum technology, which has the characteristics of quick measurement, high precision, simple operation and low cost.
In order to solve the technical problems, the invention adopts a technical scheme that: the gas concentration measuring system based on the wavelength modulation spectrum technology comprises a diode laser, a laser controller, a function waveform generator, an adder, a pressure gauge, a vacuum pump, a gas multi-channel pool, a focusing lens, a photoelectric detector, a lock-in amplifier, a DAQ acquisition card and a computer. Wherein:
the diode laser is used as a light source, the current and the temperature are controlled by a laser controller, output light sequentially passes through a gas multi-pass cell, a focusing lens, a photoelectric detector and a phase-locked amplifier, and a signal demodulated by the phase-locked amplifier is input into a DAQ acquisition card;
the function waveform generator generates sawtooth waves, and the sawtooth waves and the high-frequency sine waves output by the phase-locked amplifier are superposed by the adder to generate and input the high-frequency sine waves into the laser controller;
the phase-locked amplifier demodulates the absorption signal from the photoelectric detector, and the demodulated signal is input into a DAQ acquisition card and displayed on a computer through a LabVIEW interface.
The input end of the diode laser is connected with a laser controller and a function waveform generator, the laser controller controls the working temperature and current of the diode laser, and the function waveform generator controls the wavelength scanning range of the diode laser.
And the air inlet end of the optical multi-pass absorption cell is connected with a pressure gauge, and the air outlet end of the optical multi-pass absorption cell is connected with a vacuum pump.
Wherein, a three-dimensional model that the output light of the laser device is reflected by the gas multi-pass cell is established, and the dense light spot pattern distribution formed on the reflector surface is calculated.
The concentration is quickly inverted by establishing a fitting curve of a second harmonic signal peak value and the concentration of the calibration gas output by the phase-locked amplifier.
Compared with the prior art, the invention has the following principle and beneficial effects:
a high-frequency sine modulation signal and a low-frequency sawtooth scanning signal are superposed on the injection current of the laser to realize the modulation of the output wavelength of the laser. A three-dimensional model that the output light of the laser passes through the gas multi-pass cell for reflection is established, the internal light of the optical multi-pass cell is tracked, a series of dense light spot patterns are presented on the surface of the lens, and the utilization rate of the concave lens is improved. And (3) adopting the second harmonic component as a detection signal, and quickly inverting the concentration by establishing a fitting curve of the second harmonic signal peak value and the concentration.
Drawings
FIG. 1 is a block diagram of a gas concentration measurement system based on wavelength modulation spectroscopy in accordance with the present invention;
FIG. 2 is a block diagram of a system architecture;
FIG. 3 is a light ray reflection diagram of two identical mirrors;
FIG. 4 is a flowchart of the optical path adjustment software program;
FIG. 5 is a plot of a second harmonic signal fitted to concentration;
Detailed Description
In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the following embodiments.
Referring to fig. 1, the system is composed of four parts, namely determining the size parameters of the multi-pass cell, testing and building the system, developing experimental research and calibrating the integrated system. The gas concentration measuring system is researched by selecting devices, designing a novel spherical mirror multi-pass cell mechanical structure and designing a circuit of a related module. Then, a light ray equation is established by utilizing the reflection theorem of light to calculate the position of the light spot on the lens, different dense light spot patterns are obtained by establishing a spherical mirror optical multi-pass cell calculation model, and the light path adjustment of long light path and higher detection sensitivity is realized. And the system is set up in a test, and at the moment, a series of signals of the detector signals are processed, so that a second harmonic signal can be extracted to represent the concentration of the gas to be detected, and finally the integrated system is calibrated.
Referring to fig. 2, the system mainly includes a diode laser, a laser controller, a function waveform generator, an adder, a pressure gauge, a vacuum pump, a target gas to be measured, a gas multi-pass cell, a focusing lens, a photodetector, a lock-in amplifier, a DAQ acquisition card, and a computer. The working principle of the system is that a diode laser is used as a detection light source for providing a specific absorption spectrum wave band, current and temperature are controlled by a laser controller, and a function waveform generator generates a sawtooth wave and superposes with a high-frequency sine wave output by a phase-locked amplifier through an adder to be input into the laser controller. The output light sequentially passes through the gas multi-pass cell, the photoelectric detector and the lock-in amplifier, the laser is focused on a photosensitive surface of the detector by the lens after being reflected for multiple times by the multiple-reflection cell, and the photoelectric detector is used for converting an attenuated light intensity signal absorbed by a target gas component into an electric signal. The gas multi-pass cell is used for obtaining dense light spot patterns through multiple reflections, the path length of target gas absorption is increased, and the spectral detection sensitivity is improved. And the phase-locked amplifier performs harmonic detection on the converted electric signal, the demodulated harmonic signal is input into a DAQ acquisition card and displayed on a computer through a LabVIEW interface, and finally, a spectrum inversion algorithm is utilized to perform data processing so as to obtain the concentration information of gas absorption.
Referring to fig. 3 and 4, the optical path adjustment includes the following steps:
step one, when light spot distribution is calculated, light rays can form a dense light spot pattern on a reflector surface after being reflected for multiple times, position parameters of two reflectors are determined, and a three-dimensional model is built.
In fig. 3, M1 and M2 are two spherical mirrors with the same curvature radius, and M1 is provided with a small hole as an entrance hole and an exit hole of a multi-channel cell. When the incident light enters the multi-pass cell from the incident hole, the incident light is reflected for multiple times between the mirror surfaces and then is emitted from the emergent hole, and only three light rays are drawn in the drawing for convenient expression. The incident point and the incident vector of the given incident ray are respectively (x)0,y0,z0) (x ', y ', z '), the incident ray equation and the spherical equation can be set as:
(x-xc)2+(y-yc)2+(z-zc)2＝R2 (2)
wherein R and (x)c,yc,zc) Respectively the radius of the sphere and the surface center. The intersection point (x) of the incident ray on the spherical surface is obtained by solving equations (1) and (2)1,y1,z1). To obtain the equation of the reflected ray, let a point on the normal vector of the spherical mirror be (x)v,yv,zv) Satisfy vector ((x)0-xv),(y0-yv),(z0-zv)) perpendicular to the vector (2 (x))1-xc(,2(y1-yc),2(z1-zc) A first equation (3) can be derived. Because of the vector ((x)1-xv),(y1-yv),(z1-zv) And a vector (2 (x)1-xc),2(y1-yc),2(z1-zc) Parallel, the angle between the two vectors and the vector (x ', y ', z ') can be expressed as the incident angle or the reflection angle of the light, which are equal according to the reflection theorem of light, and thus the second equation can be expressed as (4). Due to the vector ((x)1-xv),(y1-yv),(z1-zv) Perpendicular to the point (x)1,y1,z1) The third equation can be expressed as (5) with respect to the normal vector of (b). The solution (x) of the system of equations is obtained by solving equations (3), (4) and (5)v,yv,zv) Then determining the point (x) on the reflected rayi,yi,zi) (subscript i denotes the ith reflection).
2(x0-xv)(x1-xc)+2(y0-yv)(y1-yc)+2(z0-zv)(z1-zc)＝0 (3)
((x1-xv),(y1-yv),(z1-zv))·*(x',y',z')-(2(x1-xc),2(y1-yc),2(z1-zc))·*(x',y',z')＝0 (4)
(x',y',z')×(2(x1-xc),2(y1-yc),2(z1-zc))*((x1-xc),(y1-yc),(z1-zc))＝0 (5)
xi＝2xv-x0 (6)
yi＝2yv-y0
zi＝2zv-z0
By reflecting a point (x) on the rayi,yi,zi) And (x)1,y1,z1) The reflected ray equation is expressed as:
and step two, judging whether the incident straight line and the spherical mirror have focuses. When two groups of different solutions are simultaneously formed by the incident ray equation and the spherical equation, two points of intersection of the straight line and the spherical surface are explained, and the point which is consistent with the incident ray direction is a reflection point; when two identical solutions exist, the light is tangent to the spherical surface, and a reflection point is formed; when there is no solution, it means that the ray does not intersect the sphere, i.e. the ray cannot be reflected. The light reflection satisfies the reflection law, and whether the reflection point is correct is verified by judging whether the incident angle is equal to the reflection angle.
And step three, changing the reflection times, and obtaining the direction vector of each reflection point and each reflection ray as the incident point and the incident direction vector of the next incident ray. And selecting one of the reflectors, and projecting all the light spots on the reflector to an x-y plane to draw different light spot shape graphs.
Referring to fig. 5, when light passes through the multi-pass cell containing the gas to be measured, the intensity of the light attenuates according to the concentration. To assess the linearity of the system, a least squares linear fit was made by measuring different methane concentrations from 1ppm to 20ppm and the second harmonic signal amplitude of the calibration gas output by the lock-in amplifier.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A gas concentration measuring system based on a wavelength modulation spectrum technology is characterized by comprising a diode laser, a laser controller, a function waveform generator, an adder, a pressure gauge, a vacuum pump, a gas multi-pass cell, a focusing lens, a photoelectric detector, a phase-locked amplifier, a DAQ acquisition card and a computer. Wherein:
the diode laser is used as a light source, the current and the temperature are controlled by a laser controller, output light sequentially passes through a gas multi-pass cell, a focusing lens, a photoelectric detector and a phase-locked amplifier, and a signal demodulated by the phase-locked amplifier is input into a DAQ acquisition card;
the function waveform generator generates sawtooth waves, and the sawtooth waves and the high-frequency sine waves output by the phase-locked amplifier are superposed by the adder to generate and input the high-frequency sine waves into the laser controller;
the phase-locked amplifier demodulates the absorption signal from the photoelectric detector, and the demodulated signal is input into a DAQ acquisition card and displayed on a computer through a LabVIEW interface.
2. The system according to claim 1, wherein the function waveform generator generates a sawtooth wave, and the sawtooth wave is superimposed with a high-frequency sine wave output by the lock-in amplifier via an adder to generate a modulation signal, and the modulation signal is input to the input end of the laser controller as the driving signal of the diode laser.
3. The wavelength modulation spectroscopy-based gas concentration measurement system according to claim 1, wherein the photodetector converts an optical signal received from the focusing lens into an electrical signal containing gas concentration information, resulting in a direct absorption signal.
4. The wavelength modulation spectroscopy-based gas concentration measurement system according to claim 1, wherein the laser controller adjusts the central wavelength of the laser to be near the peak of the absorption peak by adjusting the temperature of the diode laser, and adjusts the output wavelength and amplitude of the laser by adjusting the injection current of the laser.
5. The wavelength modulation spectroscopy-based gas concentration measurement system according to claim 1, wherein a gas inlet end of the gas multi-pass absorption cell is connected with a pressure gauge, and a gas outlet end of the gas multi-pass absorption cell is connected with a vacuum pump.
6. The system according to claim 1, wherein the dense spot pattern distribution formed on the reflector surface is calculated by building a three-dimensional model of the laser output light reflected by the gas multi-pass cell.
7. The wavelength modulation spectroscopy-based gas concentration measurement system according to claim 1, wherein concentration is rapidly inverted by establishing a fitted curve of second harmonic signal peak value to concentration.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117405627A (en) * | 2023-12-14 | 2024-01-16 | 北京中科智易科技股份有限公司 | Gas quality laser analysis system and analysis method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101435773A (en) * | 2008-12-02 | 2009-05-20 | 天津大学 | Gas monitoring method and apparatus based on quasi continuous diode laser modulated spectrum |
| CN103543124A (en) * | 2013-06-26 | 2014-01-29 | 天津大学 | Adjustable laser absorption spectrum gas detection method based on software phase locking |
| CN205209956U (en) * | 2015-12-11 | 2016-05-04 | 安徽理工大学 | Optic fibre methane transducer |
| CN107144549A (en) * | 2017-05-11 | 2017-09-08 | 西安科技大学 | Detection means and method based on TDLAS trace CO gas concentrations |
| CN113252573A (en) * | 2021-05-25 | 2021-08-13 | 哈尔滨工业大学 | Photo-thermal spectrum trace gas detection device and method based on cavity enhancement |
-
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- 2021-11-24 CN CN202111400274.6A patent/CN114166797A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101435773A (en) * | 2008-12-02 | 2009-05-20 | 天津大学 | Gas monitoring method and apparatus based on quasi continuous diode laser modulated spectrum |
| CN103543124A (en) * | 2013-06-26 | 2014-01-29 | 天津大学 | Adjustable laser absorption spectrum gas detection method based on software phase locking |
| CN205209956U (en) * | 2015-12-11 | 2016-05-04 | 安徽理工大学 | Optic fibre methane transducer |
| CN107144549A (en) * | 2017-05-11 | 2017-09-08 | 西安科技大学 | Detection means and method based on TDLAS trace CO gas concentrations |
| CN113252573A (en) * | 2021-05-25 | 2021-08-13 | 哈尔滨工业大学 | Photo-thermal spectrum trace gas detection device and method based on cavity enhancement |
Non-Patent Citations (1)
| Title |
|---|
| 张国贤: "长程吸收光谱技术在二氧化碳检测中的应用研究", 煤炭科技, no. 2, pages 25 - 27 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117405627A (en) * | 2023-12-14 | 2024-01-16 | 北京中科智易科技股份有限公司 | Gas quality laser analysis system and analysis method |
| CN117405627B (en) * | 2023-12-14 | 2024-02-20 | 北京中科智易科技股份有限公司 | Gas quality laser analysis system and analysis method |
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