CN116183541B - Gas measurement method and device based on FTIR technology - Google Patents

Gas measurement method and device based on FTIR technology Download PDF

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CN116183541B
CN116183541B CN202310443840.4A CN202310443840A CN116183541B CN 116183541 B CN116183541 B CN 116183541B CN 202310443840 A CN202310443840 A CN 202310443840A CN 116183541 B CN116183541 B CN 116183541B
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gas
radiation side
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light source
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CN116183541A (en
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卓然
傅明利
王邸博
黄之明
罗颜
成传晖
陈秋霖
高萌
杨伟鸿
赵思诚
蒲金雨
张晓星
张引
秦超群
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China South Power Grid International Co ltd
Hubei University of Technology
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Hubei University of Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health

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Abstract

The invention provides a gas measurement method and a gas measurement device based on an FTIR technology, comprising the following steps of establishing a gas concentration expression based on the lambert beer law; analyzing each amount in the gas concentration expression to determine a variable in the gas concentration expression; establishing a high-order compensation model for the variable to optimize; calculating the error square sum; obtaining a coefficient matrix, and completing optimization of the variables; light emitted by the light source passes through the air chamber and is filtered by the filter sheets with two different wavelengths to obtain two light radiation with two adjacent wavelengths, so that two groups of light path information are obtained, the obtained information is subjected to differential processing, the interference of zero drift of the light source and the photoelectric device can be effectively reduced, the interference of light source jitter is eliminated to a certain extent, then a high-order compensation model is established, and the gas concentration is accurately measured for temperature, pressure intensity and circuit noise.

Description

Gas measurement method and device based on FTIR technology
Technical Field
The invention relates to the technical fields of electrical engineering and optical engineering, in particular to a gas measurement method and device based on an FTIR technology.
Background
Electrochemical energy storage technology is rapidly developed, and has become one of important support technologies for renewable energy sources and smart grids. The lithium ion battery has become the most potential energy storage battery in the electrochemical energy storage field due to the advantages of high energy density, long service life, good stability and the like. However, due to technical reasons, the organic electrolyte in the lithium ion battery has a certain inflammable characteristic, has potential safety hazards in practical application, and can generate thermal runaway under extreme working conditions, smoke, fire and the like, so that personal safety is endangered. The common lithium ion battery mainly comprises a positive electrode, a negative electrode, a diaphragm and an organic electrolyte, wherein the outside of the battery is sealed by adopting a hard metal shell so as to ensure the stability of the battery structure. However, the use of metal casing sealing can result in poor overall heat dissipation performance of the lithium ion battery, and during operation under extreme conditions, a large amount of heat can be rapidly accumulated in the battery due to chemical reaction, so that thermal runaway of the battery is initiated, and after the thermal runaway occurs, H can be generated by the lithium ion battery 2 、CO、CO 2 HF and alkanes.
In order to reliably operate the lithium ion battery, the continuous and reliable operation capability of the lithium ion battery is improved, the gas content released by the lithium ion battery in the use process is monitored, the working state of the lithium ion battery can be known, the occurrence of thermal runaway is effectively avoided, and the lithium ion battery has very important practical application value. The traditional energy storage battery gas detector has poor stability, is greatly influenced by the environment, and cannot meet the requirement of accurate measurement.
The infrared spectrum can effectively characterize the molecular structure, is suitable for identifying solid, liquid and gaseous substances, and therefore, the application range of the infrared spectrum detection technology is very wide, and is an important analysis tool. The FTIR technology has good online monitoring capability, and the problem of qualitative and quantitative detection of the gas to be detected by the FTIR is conducive to timely reflecting the working state of the lithium ion battery, so that the lithium ion battery can be timely found when the lithium ion battery fails, and large-scale faults are avoided.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a gas measurement method and device based on an FTIR technology, which can detect gas to be detected.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the invention provides a gas measurement method based on FTIR technology, which comprises the following steps:
s1, establishing a gas concentration expression based on the lambert beer law;
s2, analyzing each quantity in the gas concentration expression, and determining a variable in the gas concentration expression;
s3, establishing a high-order compensation model for the variable to optimize;
s4, calculating an error square sum;
s5, obtaining a coefficient matrix, and completing optimization of the variables.
Further, the S1 includes:
s101, an expression of an output electric signal of the dual-channel optical radiation side is as follows:
Figure SMS_1
（1）
Figure SMS_2
（2）
wherein,,
Figure SMS_3
is a detection signal; />
Figure SMS_4
Is a reference signal; />
Figure SMS_5
Is->
Figure SMS_6
The light radiation side outputs an electric signal;
Figure SMS_7
is->
Figure SMS_8
The light radiation side outputs an electric signal; />
Figure SMS_9
Is the intensity of the incident light;
Figure SMS_10
and->
Figure SMS_11
The structure coefficients of the first light path and the second light path are obtained;
Figure SMS_12
and->
Figure SMS_13
Photoelectric conversion coefficients for the first detector and the second detector;
Figure SMS_14
and->
Figure SMS_15
Is at->
Figure SMS_16
And->
Figure SMS_17
Absorption coefficient of gas molecules to be measured under optical radiation;
Figure SMS_18
is the optical path length; />
Figure SMS_19
And->
Figure SMS_20
Is the interference coefficient of the light path;
s102, comparing the formula (1) with the formula (2), and obtaining the following formula:
Figure SMS_21
（3）
s103, obtaining the gas concentration:
Figure SMS_22
（4）。
further, in S2, the concentration variable expression is:
Figure SMS_23
（5）
wherein, let the
Figure SMS_24
Is->
Figure SMS_25
，/>
Figure SMS_26
Is a constant;
order the
Figure SMS_27
Is->
Figure SMS_28
，/>
Figure SMS_29
Is a constant;
order the
Figure SMS_30
Is->
Figure SMS_31
，/>
Figure SMS_32
Is a constant;
order the
Figure SMS_33
Is->
Figure SMS_34
Concentration->
Figure SMS_35
Only +.>
Figure SMS_36
Related to the following.
Further, the step S3 includes:
s301, by pressure disturbance variable
Figure SMS_37
Temperature disturbance variable->
Figure SMS_38
Circuit noise->
Figure SMS_39
Set up variable->
Figure SMS_40
Is a function of:
Figure SMS_41
（6）
s302, variable is changed
Figure SMS_42
The function of (2) is converted into a problem of surface fitting, and the higher order polynomial fitting equation is as follows:
Figure SMS_43
（7）
wherein,,
Figure SMS_44
the fitting sequence is a natural number; />
Figure SMS_45
Fitting coefficients for a higher order polynomial; />
Figure SMS_46
And->
Figure SMS_47
Is the corresponding coefficient subscript.
Further, the S4 includes:
s401, obtaining by calculating the sum of squares of errors:
Figure SMS_48
（8）
wherein,,
Figure SMS_49
is the total number of samples; />
Figure SMS_50
Outputting a signal for the light radiation side with noise; />
Figure SMS_51
To-be-identified parameters for compensating circuit noise;
compensating circuit noise input noise vector
Figure SMS_52
；
The output end has measurement noise
Figure SMS_53
Then:
Figure SMS_54
（9）
s402 obtaining the minimum value of the error square sum according to the principle of the least squares method,
the following equation needs to be satisfied:
Figure SMS_55
（10）
wherein,,
Figure SMS_56
is a coefficient of->
Figure SMS_57
、/>
Figure SMS_58
Is used for the fitting of the higher order polynomial of the coefficients.
Further, the step S5 specifically includes:
s501, deriving all coefficients:
Figure SMS_59
s502, coefficient matrix
Figure SMS_60
After obtaining the fitting coefficient matrix, the heightThe order compensation model is successfully established, the compensation of pressure intensity, temperature and circuit noise is completed, and the compensation of the variable is completed
Figure SMS_61
Is described.
Further, a gas measurement device based on FTIR technology, realized by the method, and comprising: the laser device comprises a laser light source, wherein one end of the laser light source is connected with a laser driver, the other end of the laser light source is communicated with a gas chamber, the gas chamber is communicated with a coupler, the coupler is respectively connected with a first optical filter and a second optical filter, the first optical filter and the second optical filter are communicated with a differential operational amplifier, one end of the differential operational amplifier, which is separated from the first optical filter, is communicated with a phase-locked amplifier, and one end of the phase-locked amplifier, which is separated from the differential operational amplifier, is communicated with a computer;
the laser device drives and controls the light intensity emitted by the laser light source to be
Figure SMS_69
The incident light passes through the air chamber filled with the gas to be detected, is split into two identical light beams by the coupler, and passes through the first optical filter and the second optical filter to be respectively a detection signal->
Figure SMS_65
And reference signal->
Figure SMS_73
The method comprises the steps of carrying out a first treatment on the surface of the Detection Signal->
Figure SMS_68
And reference signal->
Figure SMS_70
Is converted into +.>
Figure SMS_67
The light radiation side outputs an electrical signal +.>
Figure SMS_77
And->
Figure SMS_66
The light radiation side outputs an electrical signal +.>
Figure SMS_72
By means of the differential operational amplifier, p ∈ ->
Figure SMS_62
The light radiation side outputs an electrical signal +.>
Figure SMS_74
And->
Figure SMS_63
The light radiation side outputs an electrical signal +.>
Figure SMS_76
Differential processing is carried out, and the differential processing is transmitted to the computer terminal through the lock-in amplifier, and the differential processing is carried out on the differential processing through the computer terminal>
Figure SMS_75
The light radiation side outputs an electrical signal +.>
Figure SMS_78
And->
Figure SMS_64
The light radiation side outputs an electrical signal +.>
Figure SMS_71
Treatment is performed to obtain the final concentration.
The beneficial effects of the invention are as follows: light emitted by the light source passes through the air chamber and is filtered by the filter sheets with two different wavelengths to obtain two light radiation with two adjacent wavelengths, so that two groups of light path information are obtained, the obtained information is subjected to differential processing, the interference of zero drift of the light source and the photoelectric device can be effectively reduced, the interference of light source jitter is eliminated to a certain extent, then a high-order compensation model is established, and the gas concentration is accurately measured for temperature, pressure intensity and circuit noise.
Drawings
Fig. 1 is a schematic diagram of a gas measurement structure based on FTIR technology according to the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
A gas measurement method based on FTIR technology, comprising the steps of:
s1, establishing a gas concentration expression based on the lambert beer law;
s2, analyzing each quantity in the gas concentration expression, and determining a variable in the gas concentration expression;
s3, establishing a high-order compensation model for the variable to optimize;
s4, calculating an error square sum;
s5, obtaining a coefficient matrix, and completing optimization of the variables.
The S1 comprises the following steps:
s101, an expression of an output electric signal of the dual-channel optical radiation side is as follows:
Figure SMS_79
（1）
Figure SMS_80
（2）
wherein,,
Figure SMS_95
is a detection signal; />
Figure SMS_86
Is a reference signal; />
Figure SMS_94
Is->
Figure SMS_85
The light radiation side outputs an electric signal; />
Figure SMS_96
Is->
Figure SMS_97
The light radiation side outputs an electric signal; />
Figure SMS_98
Is the intensity of the incident light; />
Figure SMS_84
And->
Figure SMS_89
The structure coefficients of the first light path and the second light path are obtained; />
Figure SMS_81
And->
Figure SMS_92
Photoelectric conversion coefficients for the first detector and the second detector; />
Figure SMS_82
And->
Figure SMS_90
Is at->
Figure SMS_88
And->
Figure SMS_93
Absorption coefficient of gas molecules to be measured under optical radiation; />
Figure SMS_87
Is the optical path length; />
Figure SMS_91
And->
Figure SMS_83
Is the interference coefficient of the light path;
s102, comparing the formula (1) with the formula (2), and obtaining the following formula:
Figure SMS_99
（3）
s103, obtaining the gas concentration:
Figure SMS_100
（4）。
in S2, the concentration variable expression is:
Figure SMS_101
（5）
wherein, let the
Figure SMS_103
Is->
Figure SMS_107
，/>
Figure SMS_110
Is a constant; let->
Figure SMS_104
Is->
Figure SMS_109
，/>
Figure SMS_112
Is a constant; order the
Figure SMS_114
Is->
Figure SMS_102
，/>
Figure SMS_106
Is a constant; let->
Figure SMS_111
Is->
Figure SMS_113
Concentration->
Figure SMS_105
Only +.>
Figure SMS_108
Related to the following.
The step S3 comprises the following steps:
s301, by pressure disturbance variable
Figure SMS_115
Temperature disturbance variable->
Figure SMS_116
Circuit noise->
Figure SMS_117
Set up variable->
Figure SMS_118
Is a function of:
Figure SMS_119
（6）
s302, variable is changed
Figure SMS_120
The function of (2) is converted into a problem of surface fitting, and the higher order polynomial fitting equation is as follows:
Figure SMS_121
（7）
wherein,,
Figure SMS_122
the fitting sequence is a natural number; />
Figure SMS_123
Fitting coefficients for a higher order polynomial; />
Figure SMS_124
And->
Figure SMS_125
Is the corresponding coefficient subscript.
The step S4 comprises the following steps:
s401, obtaining by calculating the sum of squares of errors:
Figure SMS_126
（8）
wherein,,
Figure SMS_127
is the total number of samples; />
Figure SMS_128
Outputting a signal for the light radiation side with noise; />
Figure SMS_129
To-be-identified parameters for compensating circuit noise;
compensating circuit noise input noise vector
Figure SMS_130
；
The output end has measurement noise
Figure SMS_131
Then:
Figure SMS_132
（9）
s402, obtaining the minimum value of the error square sum according to the principle of a least square method, wherein the following equation is required to be satisfied:
Figure SMS_133
（10）
wherein,,
Figure SMS_134
is a coefficient of->
Figure SMS_135
、/>
Figure SMS_136
Is used for the fitting of the higher order polynomial of the coefficients.
The step S5 specifically comprises the following steps:
s501, deriving all coefficients:
Figure SMS_137
s502, coefficient matrix
Figure SMS_138
After the fitting coefficient matrix is obtained, the high-order compensation model is successfully established, the compensation of pressure intensity, temperature and circuit noise is completed, and the compensation of the variable is completed
Figure SMS_139
Is described.
A gas measurement device based on FTIR technology, realized by said method, and comprising: the laser light source 202, one end of the laser light source 202 is connected with the laser driver 101, the other end of the laser light source 202 is communicated with the air chamber 505, the air chamber 505 is communicated with the coupler 606, the coupler 606 is respectively connected with the first optical filter 701 and the second optical filter 702, the first optical filter 701 and the second optical filter 702 are communicated with the differential operational amplifier 111, one end of the differential operational amplifier 111 separated from the first optical filter 701 is communicated with the lock-in amplifier 122, and one end of the lock-in amplifier 122 separated from the differential operational amplifier 111 is communicated with the computer 133;
the laser driver 101 controls the laser light source 202 to emit light with a intensity of
Figure SMS_146
The incident light is divided into two identical beams by a coupler 606 through a gas chamber 505 filled with the gas to be detected, and the two identical beams are respectively detection signals through a first optical filter 701 and a second optical filter 702>
Figure SMS_143
And reference signal->
Figure SMS_154
The method comprises the steps of carrying out a first treatment on the surface of the Detection Signal->
Figure SMS_145
And reference signal->
Figure SMS_155
Is converted into +.>
Figure SMS_152
The light radiation side outputs an electrical signal +.>
Figure SMS_156
And->
Figure SMS_141
The light radiation side outputs an electrical signal +.>
Figure SMS_149
By means of a differential operational amplifier 111, p ∈ ->
Figure SMS_140
The light radiation side outputs an electrical signal +.>
Figure SMS_148
And->
Figure SMS_147
The light radiation side outputs an electrical signal +.>
Figure SMS_153
Differential processing is performed, and the differential processing is transmitted to the computer 133 terminal through the lock-in amplifier 122, and the differential processing is performed to the +/via the computer 133 terminal>
Figure SMS_144
The light radiation side outputs an electrical signal +.>
Figure SMS_150
And->
Figure SMS_142
The light radiation side outputs an electrical signal +.>
Figure SMS_151
Treatment is performed to obtain the final concentration.
Referring to fig. 1, as a specific embodiment,
a laser driver 101 for driving the laser to emit laser light of a specific wavelength band;
a laser light source 202 that emits laser light having a wavelength of 5um, and detects gas with the laser light of the wavelength band;
a gas chamber 505 into which a gas to be measured is introduced;
a getter pump 404 is installed above the air chamber 505, and functions to getter gas generated during thermal runaway of the battery into the air chamber 505;
the first optical filter 701 and the second optical filter 702 are arranged in parallel, the first optical filter 701 is connected in series with the first photodetector 901, the second optical filter 702 is connected in series with the second photodetector 100, and the first photodetector 901 and the second photodetector 100 are used for detecting optical signals.
Light emitted by the light source passes through the air chamber, then the light is filtered by two filters with different wavelengths, light radiation with adjacent wavelengths and two wavelengths is obtained, two sets of light path information are obtained, and then the two sets of information are processed, so that a desired result is obtained. The specific operation mode is as follows:
self-calibrating the laser to make the laser work in an optimal state;
opening a suction pump, and introducing the gas in the thermal runaway process of the battery into a gas pool;
turning on the laser to make the light emitted by the light source enter the gas pool;
laser is emitted in the gas pool through a series of reflections and is hit on the photoelectric detector;
the electric signal detected by the photoelectric detector is processed by a differential operational amplifier and a lock-in amplifier, and then is transmitted into a PC end;
analyzing and debugging the obtained signal at the PC end to meet the requirements;
and closing the laser, discharging the gas in the gas pool, and ending the experiment.
The gas measurement method based on the FTIR technology comprises the following principles: fourier transform infrared spectroscopy (FTIR) has advantages of high resolution, high signal-to-noise ratio, short response time, and the like, is widely used in the field of gas analysis, and is considered as one of the most ideal means for gas concentration detection. The sample to be measured is irradiated by infrared light with the frequency continuously changing, the molecular group absorbs radiation with the characteristic frequency, the vibration or rotation motion of the molecular group causes dipole moment change, and the transition from the ground state to the excited state of the vibration level and the rotation level of the molecule is generated, so that a molecular absorption spectrum is formed. The molecule absorbs a photon with energy hv from a lower energy level E1, can transit to a higher energy level E2, and the whole motion process meets the law of conservation of energy E2-E1=hv. The smaller the phase difference between the energy levels, the lower the frequency of light absorbed by the molecule and the longer the wavelength. The infrared absorption spectrum is caused by molecular vibration and rotational transition, and atoms constituting chemical bonds or functional groups are in a constantly vibrating (or rotating) state, and the vibration frequency thereof is equivalent to that of infrared light. Therefore, when the molecule is irradiated by infrared light, vibration absorption can occur to chemical bonds or functional groups in the molecule, the absorption frequencies of different chemical bonds or functional groups are different, and the molecules are positioned at different positions on the infrared spectrum, so that information of the chemical bonds or functional groups contained in the molecules can be obtained. Infrared spectrometry is essentially an analytical method for determining the molecular structure of a substance and identifying compounds based on information such as relative vibrations and molecular rotations between atoms within a molecule.
Light emitted by the light source passes through the air chamber and is filtered by the filter sheets with two different wavelengths to obtain two light radiation with two adjacent wavelengths, so that two groups of light path information are obtained, the obtained information is subjected to differential processing, the interference of zero drift of the light source and the photoelectric device can be effectively reduced, the interference of light source jitter is eliminated to a certain extent, then the high-order compensation model is used for optimizing the data, the temperature, the pressure and the optical noise are uniformly compensated, and the gas concentration is accurately measured.
The foregoing examples merely illustrate embodiments of the invention and are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present patent is to be determined by the appended claims.

Claims (2)

1. A gas measurement method based on FTIR technology, comprising the steps of:
s1, establishing a gas concentration expression based on the lambert beer law;
s2, analyzing each quantity in the gas concentration expression, and determining a variable in the gas concentration expression;
s3, establishing a high-order compensation model for the variable to optimize;
s4, calculating an error square sum;
s5, obtaining a coefficient matrix, and completing optimization of the variables;
the S1 comprises the following steps:
s101, an expression of an output electric signal of the dual-channel optical radiation side is as follows:
Figure QLYQS_1
（1）
Figure QLYQS_2
（2）
wherein,,
Figure QLYQS_11
is a detection signal; />
Figure QLYQS_14
Is a reference signal; />
Figure QLYQS_16
Is->
Figure QLYQS_17
The light radiation side outputs an electric signal; />
Figure QLYQS_18
Is->
Figure QLYQS_19
The light radiation side outputs an electric signal; />
Figure QLYQS_20
Is the intensity of the incident light; />
Figure QLYQS_3
And->
Figure QLYQS_4
The structure coefficients of the first light path and the second light path are obtained; />
Figure QLYQS_5
And->
Figure QLYQS_6
Photoelectric conversion coefficients for the first detector and the second detector; />
Figure QLYQS_9
And->
Figure QLYQS_12
Is at->
Figure QLYQS_13
And->
Figure QLYQS_15
Absorption coefficient of gas molecules to be measured under optical radiation; />
Figure QLYQS_7
Is the optical path length; />
Figure QLYQS_8
And->
Figure QLYQS_10
Is the interference coefficient of the light path;
s102, comparing the formula (1) with the formula (2), and obtaining the following formula:
Figure QLYQS_21
（3）
s103, obtaining the gas concentration:
Figure QLYQS_22
（4）；
in S2, the concentration variable expression is:
Figure QLYQS_23
（5）
wherein, let the
Figure QLYQS_25
Is->
Figure QLYQS_27
，/>
Figure QLYQS_29
Is a constant; let->
Figure QLYQS_31
Is->
Figure QLYQS_33
，/>
Figure QLYQS_35
Is a constant; let->
Figure QLYQS_36
Is->
Figure QLYQS_24
，/>
Figure QLYQS_26
Is a constant; let->
Figure QLYQS_28
Is->
Figure QLYQS_30
Concentration->
Figure QLYQS_32
Only +.>
Figure QLYQS_34
Related to;
the step S3 comprises the following steps:
s301, by pressure disturbance variable
Figure QLYQS_37
Temperature disturbance variable->
Figure QLYQS_38
Circuit noise->
Figure QLYQS_39
Set up variable->
Figure QLYQS_40
Is a function of:
Figure QLYQS_41
（6）
s302, variable is changed
Figure QLYQS_42
The function of (2) is converted into a problem of surface fitting, and the higher order polynomial fitting equation is as follows:
Figure QLYQS_43
（7）
wherein,,
Figure QLYQS_44
the fitting sequence is a natural number; />
Figure QLYQS_45
Fitting coefficients for a higher order polynomial; />
Figure QLYQS_46
And->
Figure QLYQS_47
Is a corresponding coefficient subscript;
the step S4 comprises the following steps:
s401, obtaining by calculating the sum of squares of errors:
Figure QLYQS_48
（8）
wherein,,
Figure QLYQS_49
is the total number of samples; />
Figure QLYQS_50
Outputting a signal for the light radiation side with noise; />
Figure QLYQS_51
To-be-identified parameters for compensating circuit noise;
compensating circuit noise input noise vector
Figure QLYQS_52
The method comprises the steps of carrying out a first treatment on the surface of the The output end has measuring noise->
Figure QLYQS_53
Then:
Figure QLYQS_54
（9）
s402, obtaining the minimum value of the error square sum according to the principle of a least square method, wherein the following equation is required to be satisfied:
Figure QLYQS_55
（10）
wherein,,
Figure QLYQS_56
is a coefficient of->
Figure QLYQS_57
、/>
Figure QLYQS_58
Higher order polynomial fit coefficients of (2);
the step S5 specifically comprises the following steps:
s501, deriving all coefficients:
Figure QLYQS_59
；
s502, coefficient matrix
Figure QLYQS_60
；
After the fitting coefficient matrix is obtained, the high-order compensation model is successfully established,compensation for pressure, temperature, circuit noise is completed, and compensation for the variables is completed
Figure QLYQS_61
Is described.
2. A gas measurement device based on FTIR technique, characterized in that: the method of claim 1 implemented by the apparatus, and comprising: the laser device comprises a laser light source (202), wherein one end of the laser light source (202) is connected with a laser driver (101), the other end of the laser light source (202) is communicated with a gas chamber (505), the gas chamber (505) is communicated with a coupler (606), the coupler (606) is respectively connected with a first optical filter (701) and a second optical filter (702), the first optical filter (701) and the second optical filter (702) are respectively communicated with one end of a differential operational amplifier (111), the other end of the differential operational amplifier (111) is communicated with one end of a phase-locked amplifier (122), and the other end of the phase-locked amplifier (122) is communicated with a computer (133); the laser driver (101) controls the laser light source (202) to emit light with the intensity of
Figure QLYQS_66
The incident light is divided into two identical beams by the coupler (606) through the air chamber (505) filled with the gas to be detected, and the two identical beams respectively pass through the first optical filter (701) and the second optical filter (702) and are respectively detection signals>
Figure QLYQS_68
And reference signal->
Figure QLYQS_71
The method comprises the steps of carrying out a first treatment on the surface of the Detection Signal->
Figure QLYQS_73
And reference signal->
Figure QLYQS_75
Is converted into +.>
Figure QLYQS_76
The light radiation side outputs an electrical signal +.>
Figure QLYQS_78
And->
Figure QLYQS_62
The light radiation side outputs an electrical signal +.>
Figure QLYQS_64
By means of said differential operational amplifier (111), for +.>
Figure QLYQS_67
The light radiation side outputs an electrical signal +.>
Figure QLYQS_69
And->
Figure QLYQS_70
The light radiation side outputs an electrical signal +.>
Figure QLYQS_72
Differential processing is carried out, and the differential processing is transmitted to the computer (133) end through the lock-in amplifier (122), and the differential processing is carried out through the computer (133) end pair ∈>
Figure QLYQS_74
The light radiation side outputs an electrical signal +.>
Figure QLYQS_77
And->
Figure QLYQS_63
The light radiation side outputs an electrical signal +.>
Figure QLYQS_65
Treatment is performed to obtain the final concentration.
CN202310443840.4A 2023-04-24 2023-04-24 Gas measurement method and device based on FTIR technology Active CN116183541B (en)

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CN108982396A (en) * 2018-05-30 2018-12-11 南京信息工程大学 A kind of infrared CO2Gas sensor and its calibration system and humiture compensation method
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