Gas infrared cross detection system and detection method

Abstract

The invention provides a gas infrared cross detection system and a detection method, and belongs to the technical field of gas detection. A first detection channel and a second detection channel are arranged in a cavity in parallel at an interval. The first photoacoustic receiving module converts a first photoacoustic signal generated in the first detection channel into a first electric signal. The second photoacoustic receiving module converts a second photoacoustic signal generated in the second detection channel into a second electric signal. The first signal processing module filters and amplifies the first electric signal to obtain a first detection signal. The second signal processing module filters and amplifies the second electric signal to obtain a second detection signal. And the differential amplification module performs differential amplification on the first detection signal and the second detection signal to obtain a concentration detection signal, so that the purpose of differential noise reduction is achieved, and a target signal is enhanced. The main control module determines the concentration of the detected gas according to the concentration detection signal, so that the concentration detection precision is improved, and the problem of low detection accuracy in the traditional technology is solved.

Description

Technical Field

[0001] The present application belongs to the field of gas detection technology, and in particular, relates to a gas infrared cross detection system and a detection method. Background Art

[0002] Common transformer faults, such as partial discharge and transformer overheating, often produce a variety of fault characteristic gases. The type and concentration of the fault gas produced when the transformer fails are closely related to whether the transformer fails, and are important monitoring objects for transformer fault early warning. When a transformer fails, it produces a variety of fault characteristic gases, such as hydrogen (H2), methane (CH4), acetylene (C2H2), ethylene (C2H4), ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2), etc.

[0003] The main gas detection methods are chromatography and photoacoustic spectroscopy. Chromatography is a standard laboratory method used for on-site online monitoring. It has problems such as consumables and maintenance expertise, but chromatography has disadvantages in real-time online monitoring systems. Photoacoustic spectroscopy, on the other hand, is increasingly recognized because it uses spectroscopy, has the advantages of no consumables and easy calibration. However, since noise always accompanies the photoacoustic signal during gas detection, noise will directly affect the detection accuracy of the gas. The use of a single detection light of a traditional detection system to detect the gas to be tested will result in a large error in the detection result, leading to low detection accuracy. Summary of the invention

[0004] The purpose of the present application is to provide a gas infrared cross detection system and a detection method, aiming to solve the problem of low detection accuracy existing in traditional detection systems.

[0005] The present application provides a gas infrared cross detection system, comprising:

[0006] A cavity, wherein a first detection channel and a second detection channel are arranged in parallel and spaced apart from each other;

[0007] A first photoacoustic receiving module is installed in the first detection channel, and is used to receive a first photoacoustic signal formed by the interaction of the near-infrared light in the first detection channel with the gas to be detected, and convert the first photoacoustic signal into a first electrical signal;

[0008] a first signal processing module, connected to the first photoacoustic receiving module, and configured to filter and amplify the first electrical signal to obtain a first detection signal;

[0009] A second photoacoustic receiving module is installed in the first detection channel, and is used to receive a second photoacoustic signal formed by the interaction of the mid-infrared light in the second detection channel with the measured gas, and convert the second photoacoustic signal into a second electrical signal;

[0010] a second signal processing module, connected to the second photoacoustic receiving module, and configured to filter and amplify the second electrical signal to obtain a second detection signal;

[0011] A differential amplification module, connected to the first signal processing module and the second signal processing module respectively, for differentially amplifying the first detection signal and the second detection signal to obtain a concentration detection signal;

[0012] The main control module is connected to the differential amplification module and is used to determine the concentration of the measured gas according to the concentration detection signal.

[0013] The present application provides a gas infrared cross detection method, which is applied to the gas infrared cross detection system in the above embodiment. The gas infrared cross detection method includes:

[0014] Receiving a first photoacoustic signal formed by the interaction of near-infrared light and the measured gas, and converting the first photoacoustic signal into a first electrical signal;

[0015] filtering and amplifying the first electrical signal to obtain a first detection signal;

[0016] receiving a second photoacoustic signal formed by the interaction of the mid-infrared light and the measured gas, and converting the second photoacoustic signal into a second electrical signal;

[0017] filtering and amplifying the second electrical signal to obtain a second detection signal;

[0018] performing differential amplification on the first detection signal and the second detection signal to obtain a concentration detection signal;

[0019] The concentration of the measured gas is determined according to the concentration detection signal.

[0020] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0021] Through the gas infrared cross detection system provided by the present application, near infrared detection and mid-infrared detection are performed on the same gas to be measured in the first detection channel and the second detection channel in the same cavity. The first photoacoustic receiving module converts the first photoacoustic signal formed after the near infrared light acts on the gas to be measured into a first electrical signal. The second photoacoustic receiving module converts the second photoacoustic signal formed after the mid-infrared light acts on the gas to be measured into a second electrical signal. The first signal processing module and the second signal processing module filter and amplify the first electrical signal and the second electrical signal respectively, so that the noise in the first electrical signal and the second electrical signal is removed. Further, the first signal processing module and the second signal processing module respectively amplify the filtered electrical signal, enhance the strength of the useful signal, and obtain the first detection signal and the second detection signal. The difference between the first detection signal and the second detection signal is amplified by the differential amplifier module, and the common mode signal (such as signal background noise) is suppressed, so that the signal background noise in the detection signal can be removed, the signal-to-noise ratio of the detection signal is improved, and a more accurate detection signal that can reflect the concentration of the gas to be measured is obtained. Furthermore, a more accurate concentration of the gas to be measured is obtained by the concentration detection signal output by the differential amplifier module. Therefore, through the first signal processing module, the second signal processing module and the differential amplification module, the noise in the first electrical signal corresponding to the first photoacoustic signal and the second electrical signal corresponding to the second photoacoustic signal and the signal background noise are removed, and the noise signal caused by uncontrollable factors such as the external environment can be removed, so as to obtain a more accurate detection signal that can reflect the concentration of the measured gas, thereby improving the detection accuracy and solving the problem of low detection accuracy of the traditional system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cross-sectional view of a gas infrared cross detection system provided for some embodiments of the present application;

[0023] Figure 2 A cross-sectional view of a cavity provided for some embodiments provided in the present application;

[0024] Figure 3 A schematic diagram of the structure of a gas infrared cross detection system in some embodiments provided in this application;

[0025] Figure 4 A schematic diagram of the structure of a gas infrared cross detection system in some embodiments provided in this application;

[0026] Figure 5 A schematic diagram of the circuit structure of a gas infrared cross detection system in some embodiments provided in this application;

[0027] Figure 6 A schematic diagram of the steps of the infrared cross detection method of gases in some embodiments provided in this application;

[0028] Figure 7 A schematic flow chart of steps in the first concentration interval of the infrared cross detection method for gases in some embodiments provided in the present application;

[0029] Figure 8 A schematic flow chart of steps in the second concentration interval of the infrared cross detection method for gases in some embodiments provided in the present application;

[0030] Fig. 9 A schematic flow chart of steps in the third concentration interval of the infrared cross detection method for gases in some embodiments provided in the present application;

[0031] Fig.10 This is a schematic flow chart of the steps in the fourth concentration interval of the gas infrared cross detection method in some embodiments provided in the present application. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0034] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] Most of the fault characteristic gases generated by oil-immersed transformers are directly dissolved in the transformer oil, which makes detection difficult. Through degassing, the dissolved gas in the oil is desorbed and the type and concentration of the fault characteristic gas are detected to determine whether the transformer is really faulty. The detection can detect one or more of the fault characteristic gases, which can be selected according to actual needs.

[0037] The embodiment of the present application provides a gas infrared cross detection system 100, wherein a first detection channel 113 and a second detection channel 114 are provided in a cavity 10, so that mid-infrared detection and near-infrared detection can be performed simultaneously in one detection cavity 11. Compared with the method of performing two detections in two detection cavities 11, the amount of gas required for performing two detections in the same detection cavity 11 is smaller;

[0038] In addition, when near-infrared and mid-infrared are measuring the same gas, corrections can be made based on the different absorption coefficients of near-infrared light and near-infrared light for fault characteristic gases, which can reduce errors, correct the impact of drift of near-infrared emitting mechanisms and mid-infrared emitting mechanisms, and improve the stability of the gas infrared cross-detection system 100.

[0039] The following combination Figure 1 and Figure 2 The gas infrared cross detection system 100 according to an embodiment of the present application is described.

[0040] In some embodiments, the gas infrared cross detection system 100 includes a cavity 10, a near-infrared emission mechanism 20, a mid-infrared emission mechanism 30 and a micro-sound mechanism 40; the cavity 10 has a detection cavity 11 and a first channel 12 and a second channel 13 connected to the detection cavity 11, one of the first channel 12 and the second channel 13 is used to allow gas to flow into the detection cavity 11, and the other is used to guide the gas to flow out of the detection cavity 11; the detection cavity 11 includes a first buffer cavity 111, a second buffer cavity 112, a first detection channel 113 and a second detection channel 114, the first detection channel 113 is connected between the first buffer cavity 111 and the second buffer cavity 112, the second detection channel 114 is connected between the first buffer cavity 111 and the second buffer cavity 112, and the first detection channel 113 and the second detection channel 114 are parallel and spaced; the cavity 10 has a first opening 115 connected to the first buffer cavity 111 and a second opening 116 connected to the second buffer cavity 112 The first opening 115 is located at the side of the first buffer cavity 111 facing away from the second buffer cavity 112, and the second opening 116 is located at the side of the second buffer cavity 112 facing away from the first buffer cavity 111; the first channel 12 is connected to the first buffer cavity 111, and the second buffer cavity 112 is connected to the second channel 13; the near-infrared emitting mechanism 20 is arranged at the end of the cavity 10 close to the first opening 115, and the near-infrared emitting mechanism 20 is used to emit near-infrared light 201, and the near-infrared light 201 can be injected into the first detection channel 113 through the first opening 115 and the first buffer cavity 111; the mid-infrared emitting mechanism 30 is arranged at the end of the cavity 10 close to the second opening 116, and the mid-infrared emitting mechanism 30 is used to emit mid-infrared light 301, and the mid-infrared light 301 can be injected into the second detection channel 114 through the second opening 116 and the second buffer cavity 112; the micro-sound mechanism 40 is arranged in the cavity 10, and the micro-sound mechanism 40 is used to collect the sound in the first detection channel 113 and the second detection channel 114.

[0041] The cavity 10 may refer to a component with a cavity inside, and the cavity 10 is used to enclose the detection cavity 11, the first channel 12 and the second channel 13; the cavity 10 may be made of metal material. The detection cavity 11 may refer to an internal space for passing gas to complete mid-infrared detection and near-infrared detection; when mid-infrared and near-infrared are irradiated into the detection cavity 11, a photoacoustic effect occurs in the detection cavity 11.

[0042] The first channel 12 and the second channel 13 may refer to channels for connecting the detection chamber 11 and the outside of the cavity 10. The first channel 12 may be an air inlet channel, and the second channel 13 may be an air outlet channel. The gas enters the detection chamber 11 from the first channel 12, and after the detection is completed, the gas flows out of the detection chamber 11 from the second channel 13; or, the first channel 12 is an air outlet channel, and the second channel 13 is an air inlet channel. The gas enters the detection chamber 11 from the second channel 13, and after the detection is completed, the gas flows out of the detection chamber 11 from the first channel 12.

[0043] For the convenience of explanation, the following description is made by taking the first channel 12 as an air inlet channel and the second channel 13 as an air outlet channel as an example. The cavity 10 may be a columnar structure, and the detection cavity 11 penetrates the cavity 10 along the axial direction of the cavity 10. The detection cavity 11 includes a first buffer cavity 111, a second buffer cavity 112, a first detection channel 113, and a second detection channel 114; the first buffer cavity 111 and the second buffer cavity 112 are located at both ends of the detection cavity 11, and the first detection channel 113 and the second detection channel 114 are located in the middle of the detection cavity 11, and the first detection channel 113 and the second detection channel 114 connect the first buffer cavity 111 and the second buffer cavity 112. The first buffer cavity 111 and the second buffer cavity 112 are symmetrically arranged, and the radial size of the first buffer cavity 111 and the radial size of the second buffer cavity 112 are larger than the radial size of the first detection channel 113 and the radial size of the second detection channel 114, and the space of the first buffer cavity 111 and the second buffer cavity 112 is large. The first detection channel 113 and the second detection channel 114 can be straight channels, which facilitates the near infrared light 201 and the mid infrared light 301 to pass through in a straight line, reduces obstacles, and improves detection accuracy. The first detection channel 113 and the second detection channel 114 extend along the axial direction of the detection cavity 11 and are arranged at intervals along the radial direction of the detection cavity 11.

[0044] The first channel 12 is connected to the first buffer chamber 111, and the second channel 13 is connected to the second buffer chamber 112, so that the gas enters the first buffer chamber 111 through the first channel 12, and the space of the first buffer chamber 111 is large, and the airflow can be buffered in the first buffer chamber 111, and then smoothly enter the first detection channel 113 and the second detection channel 114 for detection, thereby improving the accuracy of detection; the gas flowing out of the first detection channel 113 and the second detection channel 114 enters the second buffer chamber 112, and finally discharged through the second channel 13, wherein the space of the second buffer chamber 112 is large, and the gas can be buffered in the second buffer chamber 112, thereby reducing the impact on the detection result. In addition, the large space of the first buffer chamber 111 and the second buffer chamber 112 can attenuate external noise and improve detection accuracy.

[0045] The near-infrared emitting mechanism 20 may refer to a mechanism capable of emitting near-infrared light 201; the near-infrared emitting mechanism 20 is disposed opposite to the first detection channel 113 through the first opening 115, so that the near-infrared light 201 emitted by the near-infrared emitting mechanism 20 enters the first buffer cavity 111 from the first opening 115 and then enters the first detection cavity 11 in a straight line for detection. The mid-infrared emitting mechanism 30 may refer to a mechanism capable of emitting mid-infrared light 301; the mid-infrared emitting mechanism 30 is disposed opposite to the second detection channel 114 through the second opening 116, so that the mid-infrared light 301 emitted by the mid-infrared emitting mechanism 30 enters the second buffer cavity 112 from the second opening 116 and then enters the second detection cavity 11 in a straight line for detection.

[0046] The micro-sound mechanism 40 may refer to a mechanism capable of collecting sound; the micro-sound mechanism 40 may simultaneously obtain the sound of the first detection channel 113 and the second detection channel 114; when the gas enters the first detection channel 113 and the near-infrared light 201 is incident on the first detection channel 113, the gas in the first detection channel 113 will vibrate, thereby generating sound, and by obtaining the sound, information such as the type and concentration of the gas can be obtained. Similarly, when the gas enters the second detection channel 114 and the mid-infrared light 301 is incident on the second detection channel 114, the gas in the second detection channel 114 will vibrate, thereby generating sound, and by obtaining the sound, information such as the type and concentration of the gas can be obtained.

[0047] During the detection process, there are many gas components to be measured, and there is a certain cross-phenomenon in the absorption spectrum of the gas. When measuring under a single light source, there is a certain cross-interference. The embodiment of the present application utilizes mid-infrared and near-infrared same-cavity gas detection, which can effectively cross-verify the detection results of the two, remove interference in the gas detection process, and realize deviation warning of the detection results, so as to obtain more accurate detection results.

[0048] The gas infrared cross detection system 100 of the embodiment of the present application is provided with a first detection channel 113 and a second detection channel 114 in the cavity 10, and mid-infrared detection and near-infrared detection can be simultaneously implemented in one detection cavity 11, which can reduce the amount of gas required for detection by the gas infrared cross detection system 100, can meet the detection condition of a small amount of gas generated by a transformer fault, and also improves the accuracy of detection.

[0049] The gas infrared cross detection system 100 can perform mid-infrared detection and near-infrared detection on the gas in the same cavity 10. On the one hand, it meets the same test environment and can reduce detection errors. On the other hand, by using mid-infrared and near-infrared gas detection in the same cavity, the results of the two can be cross-verified to avoid false alarms or erroneous alarms of the transformer.

[0050] In the gas infrared cross detection system 100 of the embodiment of the present application, the first detection channel 113 and the second detection channel 114 are arranged in parallel and spaced apart, which can reduce the mutual influence between the optical path of the mid-infrared light 301 and the optical path of the near-infrared light 201, reduce interference, and improve detection accuracy. In addition, the detection channel can be reasonably designed based on the characteristics of the optical path (inconsistent characteristics such as wavelength), reduce the noise generated by the optical path, and improve detection accuracy.

[0051] In some embodiments, the micro-sound mechanism 40 includes a first photoacoustic receiving module 41 and a second photoacoustic receiving module 42. The first photoacoustic receiving module 41 is installed in the first detection channel 113, and the second photoacoustic receiving module 42 is installed in the second detection channel 114. The first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 can be, but are not limited to, microphones, etc.

[0052] By adopting the technical solution of this embodiment, the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 respectively collect the sounds of the first detection channel 113 and the second detection channel 114, which can improve the accuracy of detection; in addition, the first detection channel 113 and the second detection channel 114 are located in the same noise environment, which facilitates the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 to compare with each other, facilitates noise reduction, and improves the accuracy of detection.

[0053] In some embodiments, the first photoacoustic receiving module 41 is located at an antinode of the acoustic wave in the first detection channel 113 .

[0054] The near-infrared light 201 is incident on the first detection channel 113 to form sound. The sound is reflected in the first detection channel 113 to form standing waves. Positions with the largest sound pressure amplitude appear in the first detection channel 113. These positions are the antinodes of the sound waves in the first detection channel 113.

[0055] By adopting the technical solution of this embodiment, the sound pressure amplitude at the position of the first photoacoustic receiving module 41 is large, which can improve the sound receiving effect of the first photoacoustic receiving module 41 and improve the accuracy of the near-infrared detection result. In some embodiments, the second photoacoustic receiving module 42 is located at the antinode of the sound wave in the second detection channel 114.

[0056] The mid-infrared light 301 is injected into the second detection channel 114 to form sound, and the sound is reflected in the second detection channel 114 to form a standing wave. Positions with the largest sound pressure amplitude appear in the second detection channel 114, and these positions are the antinodes of the sound waves in the second detection channel 114. By adopting the technical solution of this embodiment, the sound pressure amplitude at the position where the second photoacoustic receiving module 42 is located is large, which can improve the sound receiving effect of the second photoacoustic receiving module 42 and improve the accuracy of the mid-infrared detection results.

[0057] In some embodiments, the first photoacoustic receiving module 41 is located at the antinode of the sound wave in the first detection channel 113; the second photoacoustic receiving module 42 is located at the antinode of the sound wave in the second detection channel 114. By adopting the technical solution of this embodiment, the sound pressure amplitude at the positions where the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 are located is large, and the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 have good sound receiving effects, which can improve the accuracy of the detection results.

[0058] In some embodiments, the detection cavity 11 is a resonant cavity. In some examples, the first buffer cavity 111 and the second buffer cavity 112 may be cylindrical cavities 10, and the first detection channel 113 and the second detection channel 114 may be circular channels, which have a simple structure, are easy to process, and have a moderate quality factor. By adopting the technical solution of this embodiment, the detection cavity 11 is a resonant cavity, and the resonant cavity can form an acoustic resonance by accumulating energy in the detection cavity 11, suppressing external noise interference, and being able to detect flowing gas, thereby improving the measurement signal-to-noise ratio and improving detection accuracy.

[0059] In some embodiments, the cavity wall of the first buffer cavity 111 opposite to the first opening 115 is provided with a third opening 1111 connected to the first channel 12. By adopting the technical solution of this embodiment, the third opening 1111, the first detection channel 113 and the second detection channel 114 are located on the same side of the first buffer cavity 111, so that after the gas enters the second buffer cavity 112 from the third opening 1111, it needs to turn and then enter the first detection channel 113 and the second detection channel 114. This turn can provide buffering, reduce noise interference, and improve detection accuracy.

[0060] In some embodiments, the first channel 12 is located between the first buffer cavity 111 and the second buffer cavity 112 and is arranged close to the first buffer cavity 111. The first channel 12 includes a first section 121 and a second section 122 that are perpendicular to each other. The first section 121 extends from the third opening 1111 along the axial direction of the first detection channel 113 toward the second buffer cavity 112 and is connected to the second section 122. In this way, the airflow bends once when flowing through the first section 121 and the second section 122, which can reduce noise interference and improve detection accuracy.

[0061] In some embodiments, the cavity wall of the second buffer cavity 112 opposite to the second opening 116 is provided with a fourth opening 1121 connected to the second channel 13. By adopting the technical solution of this embodiment, the fourth opening 1121, the first detection channel 113 and the second detection channel 114 are located on the same side of the second buffer cavity 112, so that after the gas flows out of the first detection channel 113 and the second detection channel 114, it needs to turn in the second buffer cavity 112 before entering the fourth outlet. This turn can provide buffering, reduce noise interference, and improve detection accuracy.

[0062] In some embodiments, the second channel 13 is located between the first buffer cavity 111 and the second buffer cavity 112 and is disposed close to the second buffer cavity 112. The second channel 13 includes a third section 131 and a fourth section 132 which are perpendicular to each other. The third section 131 extends from the fourth opening 1121 along the axial direction of the second detection channel 114 toward the first buffer cavity 111 and is connected to the fourth section 132. In this way, the airflow bends once during the process of flowing through the third section 131 and the fourth section 132, which can reduce noise interference and improve detection accuracy.

[0063] In some embodiments, the cavity wall of the first buffer cavity 111 opposite to the first opening 115 is provided with a third opening 1111 communicating with the first channel 12; the cavity wall of the second buffer cavity 112 opposite to the second opening 116 is provided with a fourth opening 1121 communicating with the second channel 13. By adopting the technical solution of this embodiment, noise interference can be reduced and the accuracy of detection can be improved.

[0064] In some embodiments, the near-infrared emission mechanism 20 includes a near-infrared laser 21, a first collimating lens 22, and a first dichroic mirror 23. The near-infrared laser 21 is used to emit near-infrared light 201. The first collimating lens 22, the first dichroic mirror 23, and the first buffer cavity 111 are sequentially arranged along the optical path of the near-infrared light 201; the first dichroic mirror 23 is arranged opposite to the first detection channel 113 and the second detection channel 114, and the first dichroic mirror 23 is used to allow the near-infrared light 201 to pass through and can reflect the mid-infrared light 301. The near-infrared laser 21 can refer to a component for emitting near-infrared light 201. The first collimating lens 22 can refer to an optical lens that can convert the near-infrared light 201 emitted by the near-infrared laser 21 into parallel near-infrared. The first dichroic mirror 23 can refer to a component that can allow the near-infrared light 201 to pass through and can reflect the mid-infrared light 301.

[0065] The optical path of the near-infrared light 201 is parallel to the length direction of the first detection channel 113. The near-infrared laser 21, the first collimating lens 22 and the first dichroic mirror 23 are distributed in sequence along the length direction of the first detection channel 113. The near-infrared laser 21, the first collimating lens 22 and the first dichroic mirror 23 are located outside the first buffer cavity 111, and the first dichroic mirror 23 is located between the first buffer cavity 111 and the first collimating lens 22. The near-infrared laser 21 and the first collimating lens 22 are both arranged opposite to the first detection channel 113. The first dichroic mirror 23 can be embedded in the first opening 115 or cover the first opening 115, thereby being arranged opposite to the first opening 115.

[0066] By adopting the technical solution of this embodiment, the near-infrared light 201 emitted by the near-infrared laser 21 becomes parallel near-infrared light 201 after being corrected by the first collimating lens 22. After the near-infrared light 201 passes through the first dichroic mirror 23, it enters the first buffer cavity 111 and the first detection channel 113 for detection. After the near-infrared light 201 is corrected by the first collimating lens 22, the propagation distance and concentration of the near-infrared light 201 in the first detection channel 113 can be increased, which is conducive to improving the accuracy of the detection result; in addition, after the mid-infrared light 301 emitted by the mid-infrared emitting mechanism 30 passes through the second detection channel 114 and the first buffer cavity 111, it is reflected by the first dichroic mirror 23 and enters the second detection channel 114 again, which increases the propagation distance of the mid-infrared light 301 in the second detection channel 114 and improves the accuracy of the detection result.

[0067] In some embodiments, the mid-infrared emitting mechanism 30 includes a mid-infrared laser 31, a second collimating lens 32 and a second dichroic mirror 33. The mid-infrared laser 31 is used to emit mid-infrared light 301. The second collimating lens 32, the second dichroic mirror 33 and the second buffer cavity 112 are arranged in sequence along the optical path of the mid-infrared light 301; the second dichroic mirror 33 is installed at the second opening 116, and the second dichroic mirror 33 is arranged opposite to the first detection channel 113 and the second detection channel 114. The second dichroic mirror 33 is used to allow the mid-infrared light 301 to pass through and can reflect the near-infrared light 201.

[0068] The second collimating lens 32 may refer to an optical lens capable of converting the mid-infrared light 301 emitted by the mid-infrared laser 31 into parallel mid-infrared light. The second dichroic mirror 33 may refer to a component capable of allowing the mid-infrared light 301 to pass through and capable of reflecting the near-infrared light 201. The mid-infrared laser 31, the second collimating lens 32 and the second dichroic mirror 33 are sequentially distributed along the optical path of the mid-infrared light 301. The mid-infrared laser 31, the second collimating lens 32 and the second dichroic mirror 33 are located outside the second buffer cavity 112. The second dichroic mirror 33 may be embedded in the second opening 116 or may cover the second opening 116, thereby being arranged opposite to the second opening 116.

[0069] By adopting the technical solution of this embodiment, the mid-infrared light 301 emitted by the mid-infrared laser 31 is corrected by the second collimating lens 32 and becomes parallel mid-infrared light 301. After passing through the second dichroic mirror 33, the mid-infrared light 301 enters the second buffer cavity 112 and the second detection channel 114 for detection. After the mid-infrared light 301 is corrected by the second collimating lens 32, the propagation distance and concentration of the mid-infrared light 301 in the second detection channel 114 can be increased, which is conducive to improving the accuracy of the detection result; in addition, after the near-infrared light 201 emitted by the near-infrared emitting mechanism 20 passes through the first detection channel 113 and the second buffer cavity 112, it is reflected by the second dichroic mirror 33 and enters the first detection channel 113 again, which increases the propagation distance of the near-infrared light 201 in the first detection channel 113 and improves the accuracy of the detection result.

[0070] In some embodiments, the mid-infrared emitting mechanism 30 further includes a reflector 34 , which is disposed between the second dichroic mirror 33 and the second collimating lens 32 to change the propagation direction of the mid-infrared light 301 emitted through the second collimating lens 32 .

[0071] The reflective element 34 may refer to a component that reflects the mid-infrared light 301; in some examples, the reflective element 34 may be tilted 45 degrees relative to the second dichroic mirror 33, so that the mid-infrared laser 31 and the second collimating lens 32 may be distributed radially along the second detection channel 114, thereby reducing the axial dimension of the gas infrared cross detection system 100 along the second detection channel 114.

[0072] By adopting the technical solution of this embodiment, the reflector 34 can reflect the mid-infrared light 301, thereby changing the optical path of the near-mid-infrared light 301, and can change the arrangement positions of the mid-infrared laser 31 and the second collimating lens 32, so as to make the structural arrangement more compact, which is conducive to reducing the external dimensions of the gas infrared cross detection system 100.

[0073] In some embodiments, the wavelength range of the mid-infrared light 301 is 2980nm to 3026nm. The wavelength of the mid-infrared light 301 may be 2980nm, 3026nm, and any value between 2980nm and 3026nm. For example, the wavelength of the mid-infrared light 301 may be, but is not limited to, 2980nm, 3000nm, 3010nm, 3020nm, and 3026nm. By adopting the technical solution of this embodiment, the wavelength of the mid-infrared light 301 is within this range, and the absorption line intensity of the fault characteristic gas to the mid-infrared light 301 is good, which is conducive to improving the detection accuracy.

[0074] In some embodiments, the wavelength range of the near infrared light 201 is 1500nm to 1532nm. The wavelength of the near infrared light 201 may be 1500nm, 1532nm, and any value between 1500nm and 1532nm. For example, the wavelength of the near infrared light 201 may be, but is not limited to, 1500nm, 1510nm, 1520nm, 1530nm, and 1532nm. By adopting the technical solution of this embodiment, the wavelength of the near infrared light 201 is within this range, and the absorption line intensity of the fault characteristic gas to the near infrared light 201 is good, which is conducive to improving the detection accuracy. In some embodiments, the wavelength range of the mid-infrared light 301 is 2980nm to 3026nm; the wavelength range of the near infrared light 201 is 1500nm to 1532nm.

[0075] In some examples, by using mid-infrared and near-infrared gas detection in the same cavity, the detection results of the two can be effectively cross-verified, interference can be removed during gas detection, deviation warning of detection results can be achieved, and more accurate detection results can be obtained; it can also be well achieved that when the hydrogen H2 content is less than 50μL / L and the carbon monoxide (CO) content is greater than 1000μL / L, the hydrogen detection error meets the requirements of ±2μL / L or ±30%; when the content of other hydrocarbons is less than 10μL / L, the ethane (C2H6) content is greater than 150μL / L, and the carbon dioxide (CO2) content is greater than 5000μL / L, the detection errors of methane, ethane, ethylene, and acetylene meet the requirements of ±0.5μL / L or ±30%. By adopting the technical solution of this embodiment, the absorption line intensity of the fault characteristic gas to the mid-infrared light 301 can be more than ten times that of the near-infrared light 201, and some can even be tens of thousands of times. Therefore, the mid-infrared light 301 can be used as the detection light to eliminate interference and improve the detection sensitivity and the minimum detection limit.

[0076] In some embodiments, the cavity 10 is a stainless steel cavity 10. The cavity 10 is made of stainless steel. By adopting the technical solution of this embodiment, the stainless steel cavity 10 can isolate the error introduced by external noise in the measurement process and improve the detection accuracy.

[0077] In the process of detecting the gas to be measured, noise always exists together with the photoacoustic signal, and the size of the noise directly affects the detection sensitivity of the gas. The sources of noise include electrical noise of electronic components, noise caused by Brownian motion of gas molecules, noise in the system's surrounding environment, noise caused by gas flow in the photoacoustic cell, noise generated by mechanical chopper vibration and friction, noise generated by the inner wall of the photoacoustic cell and the window piece absorbing modulated light energy, etc. In order to solve the problem of low detection accuracy caused by using a single detection light of a traditional detection system to detect the gas to be measured in the above-mentioned noisy environment, the present application provides a gas infrared cross detection system 100.

[0078] See also Figure 3 The present application provides a gas infrared cross detection system 100. The gas infrared cross detection system 100 includes a first photoacoustic receiving module 41, a first signal processing module 410, a second photoacoustic receiving module 42, a second signal processing module 420, a differential amplifier module 50 and a main control module 70. The first photoacoustic receiving module 41 is used to receive a first photoacoustic signal formed by the interaction of near-infrared light in the first detection channel 113 of the cavity 10 with the gas to be detected, and convert the first photoacoustic signal into a first electrical signal. The first signal processing module 410 is connected to the first photoacoustic receiving module 41, and is used to filter and amplify the first electrical signal to obtain a first detection signal.

[0079] The second photoacoustic receiving module 42 is used to receive the second photoacoustic signal formed by the interaction of the mid-infrared light and the measured gas in the second detection channel 114 of the cavity 10, and convert the second photoacoustic signal into a second electrical signal. The second detection channel 114 is arranged in parallel with the first detection channel 113 in the cavity 10. The second signal processing module 420 is connected to the second photoacoustic receiving module 42, and is used to filter and amplify the second electrical signal to obtain a second detection signal. The differential amplifier module 50 is respectively connected to the first signal processing module 410 and the second signal processing module 420, and is used to differentially amplify the first detection signal and the second detection signal to obtain a concentration detection signal. The main control module 70 is connected to the differential amplifier module 50, and is used to determine the concentration of the measured gas according to the concentration detection signal.

[0080] In this embodiment, the absorption effect of the measured gas on near-infrared light will cause electronic energy level transitions, and the electrons after the transition will produce non-radiative relaxation to release heat, and the periodic heat changes will stimulate changes in sound pressure, thereby generating a first photoacoustic signal. In the process of the near-infrared light acting on the measured gas, the intensity of the photoacoustic signal directly reflects the concentration information of the gas molecules. The absorption effect of the measured gas on mid-infrared light will also cause electronic energy level transitions, and the electrons after the transition will produce non-radiative relaxation to release heat, and the periodic heat changes will stimulate changes in sound pressure, thereby generating a second photoacoustic signal. Since the wavelength ranges of near-infrared light and mid-infrared light are different, the first photoacoustic signal and the second electrical signal formed after acting on the measured gas are also different.

[0081] The first detection channel 113 and the second detection channel 114 are located in the same cavity 10. The gas to be measured enters the cavity 10, and enters the first detection channel 113 and the second detection channel 114 respectively. The first photoacoustic receiving module 41 is installed in the first detection channel 113, and the second photoacoustic receiving module 42 is installed in the second detection channel 114. The description of the structural connection relationship can refer to the relevant description in the above embodiment. The first photoacoustic receiving module 41 is capable of receiving the first photoacoustic signal and converting it into a first electrical signal. In one embodiment, the first photoacoustic receiving module 41 can be but not limited to a microphone (which can also be understood as a microphone), etc. The first signal processing module 410 is capable of filtering and amplifying the first electrical signal. After the first signal processing module 410 filters the first electrical signal, it can remove the noise in the first electrical signal, so that the detection signal is purer and more conducive to the subsequent concentration detection of the gas to be measured. The first signal processing module 410 amplifies the filtered signal, and can amplify the useful signal in the first electrical signal, so that it can overcome signal attenuation during transmission, ensure that the signal can maintain sufficient strength over a long distance, so as to enhance the strength of the useful signal and improve the signal-to-noise ratio. Then, the first detection signal obtained after filtering and amplifying the first electrical signal is input to an input end of the differential amplifier module 50. In one embodiment, the first signal processing module 410 includes components such as resistors, capacitors, inductors, and amplifiers that can realize filtering and amplification functions.

[0082] The second photoacoustic receiving module 42 can realize the reception of the second photoacoustic signal and convert it into a second electrical signal. In one embodiment, the second photoacoustic receiving module 42 can be, but not limited to, a microphone (which can also be understood as a microphone), etc. The second signal processing module 420 can filter and amplify the second electrical signal. After the second signal processing module 420 filters the second electrical signal, it can remove the noise in the second electrical signal, so that the detection signal is purer and more conducive to the subsequent concentration detection of the measured gas. The second signal processing module 420 amplifies the filtered signal, and can amplify the useful signal in the second electrical signal, so that it can overcome signal attenuation during transmission, ensuring that the useful signal can maintain sufficient strength over a long distance, so as to enhance the strength of the useful signal and improve the signal-to-noise ratio. Then, the second detection signal obtained after filtering and amplifying the second electrical signal is input to another input end of the differential amplifier module 50. In one embodiment, the second signal processing module 420 includes components such as resistors, capacitors, inductors, and amplifiers that can realize filtering and amplification functions.

[0083] The first detection channel 113 and the second detection channel 114 have the same noise environment. The first electrical signal and the second electrical signal received and converted by the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 can be compared and referenced with each other, thereby achieving noise reduction and enhancing the target signal required for detection to improve the accuracy of concentration detection. The differential amplification module 50 performs differential amplification on the first detection signal and the second detection signal, which can be understood as taking any one of the first detection signal and the second detection signal as the detection signal and the other as the reference signal for differential amplification processing. It can also be understood as taking the first detection signal as the detection signal and the second detection signal as the reference signal. Alternatively, taking the second detection signal as the detection signal and the first detection signal as the reference signal. The differential amplification module 50 performs differential amplification on the first detection signal and the second detection signal, which can suppress common mode noise, that is, it has a strong inhibitory effect on the same noise signal at the two input ends. The differential amplifier module 50 amplifies the difference between the first detection signal and the second detection signal, suppresses the common mode signal (such as signal background noise), can remove the signal background noise in the detection signal, improve the signal-to-noise ratio of the signal, and obtain a more accurate detection signal that can reflect the concentration of the measured gas.

[0084] In one embodiment, the differential amplifier module 50 includes at least one differential amplifier, and may also include one or more components of a resistor, a power supply, a protection diode, and a constant current source. In one embodiment, the differential amplifier module 50 may be a differential low offset voltage instrument amplifier. The differential low offset voltage instrument amplifier includes a detection terminal and a reference terminal, and has the advantages of high common mode rejection ratio, low noise, low linear error, low offset drift, and sufficient bandwidth, and can more accurately reduce the signal background noise in the first detection signal and the second detection signal.

[0085] Through the public calibration between the standard gas of known gas concentration and the concentration detection signal. When the main control module 70 receives the unknown concentration detection signal, the concentration of the measured gas corresponding to the public calibration is retrieved. In one embodiment, the main control module 70 can be a computing device such as a computer, a notebook, a handheld computer and a cloud server. The main control module 70 can also be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0086] Through the gas infrared cross detection system 100 provided in the present application, near-infrared detection and mid-infrared detection are performed on the same gas to be measured in the first detection channel 113 and the second detection channel 114 in the same cavity 10. The first photoacoustic receiving module 41 converts the first photoacoustic signal formed by the action of near-infrared light on the gas to be measured into a first electrical signal. The second photoacoustic receiving module 42 converts the second photoacoustic signal formed by the action of mid-infrared light on the gas to be measured into a second electrical signal. The first electrical signal and the second electrical signal are filtered and amplified by the first signal processing module 410 and the second signal processing module 420, respectively, so that the noise in the first electrical signal and the second electrical signal is removed. Furthermore, the filtered electrical signals are amplified by the first signal processing module 410 and the second signal processing module 420, respectively, to enhance the strength of the useful signal, and obtain the first detection signal and the second detection signal. By amplifying the difference between the first detection signal and the second detection signal through the differential amplifier module 50, the common mode signal (such as signal background noise) is suppressed, and the signal background noise in the detection signal can be removed, thereby improving the signal-to-noise ratio of the detection signal and obtaining a more accurate detection signal that can reflect the concentration of the measured gas. Furthermore, a more accurate concentration of the measured gas is obtained through the concentration detection signal output by the differential amplifier module 50. Therefore, through the first signal processing module 410, the second signal processing module 420 and the differential amplifier module 50, the noise and signal background noise in the first electrical signal corresponding to the first photoacoustic signal and the second electrical signal corresponding to the second photoacoustic signal are removed, and the noise signal caused by uncontrollable factors such as the external environment can be removed, and a more accurate detection signal that can reflect the concentration of the measured gas is obtained, thereby improving the detection accuracy and solving the problem of low detection accuracy of the traditional system.

[0087] See also Figure 4 In one embodiment, the gas infrared cross detection system 100 further includes a stable output module 60. The stable output module 60 is connected to the differential amplifier module 50 and the main control module 70 respectively, and is used to filter the concentration detection signal output by the differential amplifier module 50 and transmit it to the main control module 70. In addition, the stable output module 60 can also play a role in stable output, so that the concentration detection signal output by the differential amplifier module 50 is stably transmitted to the main control module 70.

[0088] In this embodiment, the components in the concentration detection signal output by the differential amplifier module 50 can be filtered out by the stable output module 60, so that the output signal is smoother and the interference of noise is reduced. The stable output module 60 is arranged at the output end of the differential amplifier module 50, and can also ensure the stability of the concentration detection signal output by the differential amplifier module 50, and can ensure that the circuit can output stably under various conditions, avoiding the occurrence of problems such as self-excited oscillation.

[0089] See also Figure 5 In one embodiment, the first signal processing module 410 includes a first filter circuit 411 and a first preamplifier circuit 412. The first end of the first filter circuit 411 is connected to the output end of the first photoacoustic receiving module 41. The second end of the first filter circuit 411 is connected to the first end of the first preamplifier circuit 412. The first filter circuit 411 is used to filter the first electrical signal to obtain a filtered first electrical signal. The second end of the first preamplifier circuit 412 is connected to the first end of the differential amplifier module 50, and is used to amplify the filtered first electrical signal to obtain a first detection signal.

[0090] In this embodiment, the first filter circuit 411 is connected between the first photoacoustic receiving module 41 and the first preamplifier circuit 412. The first filter circuit 411 receives the first electrical signal output by the first photoacoustic receiving module 41, and performs filtering processing on the first electrical signal, which can remove the noise in the first electrical signal, making the detection signal purer and more conducive to the subsequent concentration detection of the gas under test. The first preamplifier circuit 412 receives the filtered first electrical signal output by the first filter circuit 411, and performs amplification processing on the filtered first electrical signal, so that the filtered first electrical signal can overcome signal attenuation during transmission, ensuring that the useful signal can maintain sufficient strength over a long distance, so as to enhance the strength of the useful signal and improve the signal-to-noise ratio. Furthermore, after filtering and amplifying the first electrical signal, a first detection signal is formed, which can more accurately reflect the concentration information of the gas under test. In one embodiment, the first filter circuit 411 can be an active filter or a passive filter, which can be selected according to the actual application scenario.

[0091] In one embodiment, when the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 are microphones, the first photoacoustic receiving module 41 and the second photoacoustic receiving module 42 are powered by a high-precision voltage source.

[0092] In one embodiment, the first filtering circuit 411 includes a third capacitor C3, a seventh resistor R7, and a ninth resistor R9. One end of the third capacitor C3 is connected to the output end of the first photoacoustic receiving module 41. The other end of the third capacitor C3 is connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the first end of the first preamplifier circuit 412. One end of the ninth resistor R9 is connected to the other end of the third capacitor C3. The other end of the ninth resistor R9 is grounded. In this embodiment, the capacitance value of the third capacitor C3, the resistance value of the seventh resistor R7, and the resistance value of the ninth resistor R9 can be set according to the actual application scenario, and are not specifically limited in this application.

[0093] In one embodiment, the first preamplifier circuit 412 includes a first amplifier U1, an eighth resistor R8, a tenth resistor R10, and an eleventh resistor R11. A first end of the first amplifier U1 is connected to a second end of the first filter circuit 411. A second end of the first amplifier U1 is connected to one end of the tenth resistor R10. The other end of the tenth resistor R10 is grounded. One end of the eighth resistor R8 is connected to a third end of the first amplifier U1. The other end of the eighth resistor R8 is connected to a second end of the differential amplifier module 50. One end of the eleventh resistor R11 is connected to the third end of the first amplifier U1. The other end of the eleventh resistor R11 is connected to the second end of the first amplifier U1.

[0094] In this embodiment, the first end of the first amplifier U1 is the first input end, and the second end of the first amplifier U1 is the second input end. The third end of the first amplifier U1 is the output end. The fourth end, the fifth end, the sixth end, the seventh end and the eighth end of the first amplifier U1 can be respectively the positive power supply end, the ground end of the input port, the negative power supply end, the control end and the ground end of the output port. By setting the eighth resistor R8, the tenth resistor R10 and the eleventh resistor R11 at the input end and the output end respectively, the negative feedback of the first amplifier U1 can be established, the performance parameters of the first amplifier U1 can be adjusted and the stability of the first amplifier U1 can be improved.

[0095] In one embodiment, the first amplifier U1 may be a low noise preamplifier. The resistance values ​​of the eighth resistor R8, the tenth resistor R10 and the eleventh resistor R11 may be set according to actual application scenarios and are not specifically limited in this application.

[0096] In one embodiment, the second signal processing module 420 includes a second filter circuit 421 and a second preamplifier circuit 422. The first end of the second filter circuit 421 is connected to the output end of the second photoacoustic receiving module 42. The second end of the second filter circuit 421 is connected to the first end of the second preamplifier circuit 422. The second filter circuit 421 is used to filter the second electrical signal to obtain a filtered second electrical signal. The second end of the second preamplifier circuit 422 is connected to the second end of the differential amplifier module 50 to amplify the filtered second electrical signal to obtain a second detection signal.

[0097] In this embodiment, the second filter circuit 421 is connected between the second photoacoustic receiving module 42 and the second preamplifier circuit 422. The second filter circuit 421 receives the second electrical signal output by the second photoacoustic receiving module 42, and performs filtering processing on the second electrical signal, which can remove the noise in the second electrical signal, making the detection signal purer and more conducive to the subsequent concentration detection of the gas under test. The second preamplifier circuit 422 receives the filtered second electrical signal output by the second filter circuit 421, and amplifies the filtered second electrical signal, so that the filtered second electrical signal can overcome signal attenuation during transmission, ensuring that the useful signal can maintain sufficient strength over a long distance, so as to enhance the strength of the useful signal and improve the signal-to-noise ratio. Furthermore, after filtering and amplifying the second electrical signal, a second detection signal is formed, which can more accurately reflect the concentration information of the gas under test. In one embodiment, the second filter circuit 421 can be an active filter or a passive filter, which can be selected according to the actual application scenario.

[0098] In one embodiment, the second filtering circuit 421 includes a first capacitor C1, a first resistor R1, and a second resistor R2. One end of the first capacitor C1 is connected to the output end of the second photoacoustic receiving module 42. One end of the first resistor R1 is connected to the other end of the first capacitor C1. The other end of the first resistor R1 is connected to the first end of the second preamplifier circuit 422. One end of the second resistor R2 is connected to the other end of the first capacitor C1. The other end of the second resistor R2 is grounded.

[0099] In this embodiment, the capacitance value of the first capacitor C1, the resistance value of the first resistor R1, and the resistance value of the second resistor R2 can be set according to the actual application scenario, and are not specifically limited in this application. In this embodiment, the circuit connection structure of the second filter circuit 421 is the same as the circuit connection structure of the first filter circuit 411, ensuring that the second electrical signal and the first electrical signal have the same transmission path during the transmission process, and can more accurately perform differential amplification at the differential amplifier module 50, suppressing the common mode signal (such as signal background noise) to remove the signal background noise.

[0100] In one embodiment, the second preamplifier circuit 422 includes a second amplifier U2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. A first end of the second amplifier U2 is connected to a second end of the second filter circuit 421. A second end of the second amplifier U2 is connected to one end of the third resistor R3. The other end of the third resistor R3 is grounded. One end of the fourth resistor R4 is connected to a third end of the second amplifier U2. The other end of the fourth resistor R4 is connected to a first end of the differential amplifier module 50. One end of the fifth resistor R5 is connected to a third end of the second amplifier U2. The other end of the fifth resistor R5 is connected to a second end of the second amplifier U2.

[0101] In this embodiment, the first end of the second amplifier U2 is the first input end, and the second end of the first amplifier U1 is the second input end. The third end of the first amplifier U1 is the output end. The fourth end, the fifth end, the sixth end, the seventh end and the eighth end of the second amplifier U2 can be respectively the positive power supply end, the ground end of the input port, the negative power supply end, the control end and the ground end of the output port. By setting the third resistor R3, the fourth resistor R4 and the fifth resistor R5 at the input end and the output end respectively, the negative feedback of the second amplifier U2 can be established, the performance parameters of the second amplifier U2 can be adjusted and the stability of the second amplifier U2 can be improved.

[0102] In one embodiment, the second amplifier U2 may be a low noise preamplifier. The resistance value of the third resistor R3, the resistance value of the fourth resistor R4 and the resistance value of the fifth resistor R5 may be set according to the actual application scenario and are not specifically limited in this application.

[0103] In one embodiment, the differential amplifier module 50 can be a differential low offset voltage instrument amplifier. The first end of the differential amplifier module 50 is a first input end, which is connected to the other end of the eighth resistor. The second end of the differential amplifier module 50 is a second input end, which is connected to the other end of the fourth resistor. The third end of the differential amplifier module 50 is an output end, which is connected to the input end of the stable output module 60. The fourth end, the fifth end, the sixth end, the seventh end, and the eighth end of the differential amplifier module 50 can be a reference end, a gain setting end, a power supply end, etc., respectively. The definition and function of the specific port can refer to the corresponding data manual to determine the detailed information and usage of each port when using it.

[0104] In one embodiment, the stable output module 60 includes a second capacitor C2 and a sixth resistor R6. One end of the sixth resistor R6 is connected to the third end of the differential amplifier module 50. The concentration detection signal output by the differential amplifier module 50 is processed by the stable output module 60 and then output to the main control module 70.

[0105] See also Figure 6The present application provides a gas infrared cross detection method, which is applied to a gas infrared cross detection system 100. The gas infrared cross detection system 100 includes a first detection channel 113 and a second detection channel 114 of a cavity 10, and the second detection channel 114 is arranged in parallel with the first detection channel 113 and spaced apart in the cavity 10. The gas infrared cross detection method includes:

[0106] Step S10, receiving a first photoacoustic signal formed by the interaction of the near-infrared light in the first detection channel 113 of the cavity 10 with the gas to be detected, and converting the first photoacoustic signal into a first electrical signal;

[0107] Step S20, filtering and amplifying the first electrical signal to obtain a first detection signal;

[0108] Step S30, receiving a second photoacoustic signal formed by the interaction between the mid-infrared light and the gas under test in the second detection channel 114 of the cavity 10, and converting the second photoacoustic signal into a second electrical signal;

[0109] Step S40, filtering and amplifying the second electrical signal to obtain a second detection signal;

[0110] Step S50, differentially amplifying the first detection signal and the second detection signal to obtain a concentration detection signal;

[0111] Step S60, determining the concentration of the gas to be measured according to the concentration detection signal.

[0112] In this embodiment, the relevant descriptions of steps S10 to S60 can refer to the relevant descriptions of the first photoacoustic receiving module 41, the first signal processing module 410, the second photoacoustic receiving module 42, the second signal processing module 420, the differential amplification module 50 and the main control module 70 in the above embodiments.

[0113] In one embodiment, step S60, the step of determining the concentration of the gas to be measured according to the concentration detection signal, includes:

[0114] Step S610, determining a first concentration of the gas to be measured according to the first concentration detection signal; the first concentration detection signal is determined after the first detection signal is used as a detection signal and the second detection signal is used as a reference signal through the differential amplifier module 50;

[0115] Step S620, determining a second concentration of the gas to be measured according to the second concentration detection signal; the second concentration detection signal is determined after the second detection signal is used as a detection signal and the first detection signal is used as a reference signal through the differential amplifier module 50;

[0116] In one embodiment, after the step S60 of determining the concentration of the gas to be measured according to the concentration detection signal, the method further comprises:

[0117] Step S70: detecting the operating state of the transformer according to the first concentration and the second concentration.

[0118] In this embodiment, in step S610, a public calibration is performed between a standard gas with a known gas concentration and a concentration detection signal. When the main control module 70 receives a first concentration detection signal, the first concentration of the gas to be measured corresponding to the public calibration is retrieved. The first concentration detection signal is a detection signal that can reflect the concentration information of gas molecules during the process of the near-infrared light acting on the gas to be measured. The first concentration of the gas to be measured detected by the near-infrared light can be known through the first concentration detection signal.

[0119] In step S620, when the main control module 70 receives the second concentration detection signal, the second concentration of the measured gas corresponding to the public calibration is retrieved. The second concentration detection signal is a detection signal that can reflect the concentration information of gas molecules during the process of the mid-infrared light acting on the measured gas. The second concentration of the measured gas detected by the mid-infrared light can be known through the second concentration detection signal.

[0120] In step S70, the first concentration reflects the concentration of the measured gas obtained by using the characteristic wavelength of near-infrared light as the detection wavelength. The second concentration reflects the concentration of the measured gas obtained by using the characteristic wavelength of mid-infrared light as the detection wavelength. When the same measured gas is measured by near-infrared light and mid-infrared light, the first concentration obtained by detection is compared with the second concentration, which can be used as a reference to each other to achieve cross-validation and determine the reliability of the obtained concentration of the measured gas, thereby further improving the accuracy of the gas infrared cross detection method and avoiding false alarms or wrong alarms of the transformer.

[0121] See also Figure 7 In one embodiment, step S70, the step of detecting the operating state of the transformer according to the first concentration and the second concentration, includes:

[0122] Step S710, determining whether the first concentration is within the standard range of the discrete data group to which it belongs, and whether the second concentration is within the standard range of the discrete data group to which it belongs;

[0123] Step S720: If yes, weighted average processing is performed on the first concentration and the second concentration to obtain a cross detection concentration, and a concentration interval corresponding to the cross detection concentration is determined according to the cross detection concentration;

[0124] Step S730: If not, continue to perform secondary gas infrared cross detection.

[0125] In this embodiment, the standard range of the discrete data group in step S710 can be understood as the range of the average value in the discrete data group plus or minus 3 times the standard deviation, and can also be understood as the range of the average value in the discrete data group plus or minus 2 times the standard deviation. By judging whether the first concentration is within the standard range of the discrete data group to which it belongs, it can be known whether the data of the first concentration is abnormal. If the first concentration is within the standard range of the discrete data group to which it belongs, the data of the first concentration is normal data. If the first concentration is outside the standard range of the discrete data group to which it belongs, the data of the first concentration is abnormal data. In this embodiment, by judging whether the first concentration is within the standard range of the discrete data group to which it belongs, the first concentration can be compared with the standard range of its own discrete data group to which it belongs, so as to realize the self-data verification of the first concentration.

[0126] By judging whether the second concentration is within the standard range of the discrete data group to which it belongs, it can be known whether the data of the second concentration is abnormal. If the second concentration is within the standard range of the discrete data group to which it belongs, the data of the second concentration is normal data. If the second concentration is outside the standard range of the discrete data group to which it belongs, the data of the second concentration is abnormal data. In this embodiment, by judging whether the second concentration is within the standard range of the discrete data group to which it belongs, the second concentration can be compared with the standard range of its own discrete data group to which it belongs, thereby realizing the self-data verification of the second concentration.

[0127] When the first concentration is within the standard range of the discrete data group to which it belongs, and the second concentration is within the standard range of the discrete data group to which it belongs, it indicates that both the first concentration and the second concentration are normal data, and step S720 can be continued to be executed to perform weighted averaging on the first concentration and the second concentration. In one embodiment, the weight coefficient of the weighted averaging process can be set according to the numerical values ​​of the first concentration and the second concentration. For example: the first concentration is 4.8ppm, the second concentration is 5.2ppm, and both are 0.2ppm away from the concentration interval demarcation point 5.0ppm, that is, 0.2ppm:0.2ppm is 1:1, then the weight coefficient of the first concentration is set to 50%, and the weight coefficient of the second concentration is set to 50%. Alternatively, the first concentration is 4.7ppm, the second concentration is 5.2ppm, and both are 0.3ppm and 0.2ppm away from the concentration interval demarcation point 5.0ppm, that is, 0.3ppm:0.2ppm is 3:2, then the weight coefficient of the first concentration is set to 60%, and the weight coefficient of the second concentration is set to 40%. By analogy, the weight coefficient of the weighted average processing can be set according to the difference between the first concentration and the second concentration and the boundary point of the concentration interval.

[0128] After weighted averaging the first concentration and the second concentration, a cross-detection concentration is obtained, which integrates the detection results of near-infrared light and mid-infrared light. It no longer relies solely on a single detection light to determine the concentration of the measured gas, thereby improving the accuracy of the gas infrared cross-detection method and avoiding false alarms or wrong alarms of the transformer.

[0129] When one or both of the first concentration and the second concentration are outside the standard range of the discrete data group, it indicates that at least one of the first concentration and the second concentration is abnormal data, and step S730 is executed to continue to perform secondary gas infrared cross detection. Since at least one of the first concentration and the second concentration does not conform to the distribution range of normal data, it means that the data is abnormal data, and a secondary re-inspection is required to further confirm the reliability of the data. The secondary gas infrared cross detection can be understood as a second detection using the gas infrared cross detection method provided in the present application. By performing the secondary gas infrared cross detection, the error caused by various factors in the initial detection can be reduced, and the reliability of the detection results can be further confirmed to avoid false alarms or wrong alarms of the transformer.

[0130] See also Figure 7 In one embodiment, step S70, the step of detecting the operating state of the transformer according to the first concentration and the second concentration, further includes:

[0131] Step S741, if the cross-detection concentration is within the first concentration interval, determine whether the first concentration and the second concentration are both less than the first threshold; the first concentration interval is an interval range less than the first concentration threshold;

[0132] Step S742: If yes, evaluating the operation state of the transformer according to the maximum value of the first concentration and the second concentration;

[0133] If not, continue to perform secondary gas infrared cross detection, that is, execute step S730.

[0134] In this embodiment, the first concentration threshold is 0.2ppm. Then the first concentration interval is less than 0.2ppm. If the cross detection concentration is within the first concentration interval, it can also be understood that the cross detection concentration is less than the first concentration threshold, or it can also be understood that the cross detection concentration is less than 0.2ppm. The first concentration interval can be understood as a low concentration interval.

[0135] Furthermore, it is necessary to compare and judge the first concentration and the second concentration with the first threshold value respectively for troubleshooting. It is determined whether the first concentration and the second concentration are both less than the first threshold value. The first threshold value may be a concentration threshold value that can reflect the presence of the measured gas. Whether the first concentration and the second concentration are both less than the first threshold value can be understood as the first concentration is less than the first threshold value, and the second concentration is less than the first threshold value.

[0136] If both the first concentration and the second concentration are less than the first threshold, step S742 is executed, and the process further jumps to steps S781 to S784 to further determine the warning state.

[0137] If one or both of the first concentration and the second concentration are less than the first threshold, step S743 is executed, and the process jumps to steps S791 to S795 to further determine the warning state. For step S743, reference may be made to the relevant description of step S730 in the above embodiment.

[0138] Through the steps in this embodiment, the first concentration and the second concentration are cross-validated, and the accuracy of the first concentration and the second concentration can be further detected within the first concentration range, and then corresponding measures are taken according to the first concentration and the second concentration to further confirm the reliability of the detection result, so as to avoid the occurrence of false alarms or wrong alarms of the transformer. Through steps S741 to S743, the accuracy of the gas infrared cross detection method is improved.

[0139] See also Figure 8 In one embodiment, step S70, the step of detecting the operating state of the transformer according to the first concentration and the second concentration, further includes:

[0140] Step S751, if the cross-detection concentration is within the second concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a first concentration difference; the second concentration interval is an interval range greater than or equal to the first concentration threshold and less than the second concentration threshold;

[0141] Step S752, determining whether the first concentration difference is within a first difference range;

[0142] If yes, the operation state of the transformer is evaluated according to the maximum value of the first concentration and the second concentration, that is, step S742 is executed;

[0143] If not, continue to perform secondary gas infrared cross detection, that is, execute step S730.

[0144] In this embodiment, the second concentration threshold value may be 5.0ppm. The second concentration interval is an interval range greater than or equal to 0.2ppm and less than 5.0ppm. If the cross-detection concentration is within the second concentration interval, it may also be understood as being within 0.2ppm to 5.0ppm. The second concentration interval may be understood as a medium-low concentration interval. If the cross-detection concentration is within the second concentration interval, the first concentration difference formed by the first concentration and the second concentration is calculated. Furthermore, the first concentration difference is judged.

[0145] If the first concentration difference is within the first difference range, step S753 is executed, and the process further jumps to steps S781 to S784 to further determine the warning state.

[0146] If the first concentration difference is not within the first difference range, step S754 is executed, and the process jumps to steps S791 to S795 to further determine the warning state. The description of step S754 may refer to the description of step S730 in the above embodiment.

[0147] In one embodiment, the first difference range may be from -0.2 ppm to 0.2 ppm. Alternatively, the first difference range may be from -30% of the minimum of the first concentration and the second concentration to +30% of the minimum of the first concentration and the second concentration.

[0148] The first difference range is selected according to the values ​​of the first concentration and the second concentration. The largest interval between the interval of -0.2ppm to 0.2ppm and the interval of -30% of the minimum value to +30% of the minimum value is determined as the first difference range.

[0149] In one embodiment, the first concentration is 0.5ppm and the second concentration is 0.4ppm, then the first concentration difference is 0.1ppm. The second concentration is less than the first concentration, then -30% of the second concentration is calculated as 0.4ppm×(-30%)=-0.12ppm, and +30% of the second concentration is 0.4ppm×(+30%)=0.12ppm. The interval range of -0.2ppm to 0.2ppm is greater than the interval range of -0.12ppm to 0.12ppm, then the first difference range in this embodiment selects the interval range of -0.2ppm to 0.2ppm.

[0150] Further, step S752 is executed to determine whether the first concentration difference 0.1 ppm is within the interval range of -0.2 ppm to 0.2 ppm.

[0151] In one embodiment, the first concentration is 4.0ppm and the second concentration is 4.1ppm, and the first concentration difference is 0.1ppm. The first concentration is less than the second concentration, and the -30% of the first concentration is calculated as 4.0ppm×(-30%)=-1.2ppm, and the +30% of the first concentration is 4.0ppm×(+30%)=1.2ppm. The interval range of -1.2ppm to 1.2ppm is greater than the interval range of -0.2ppm to 0.2ppm, and the first difference range in this embodiment is the interval range of -1.2ppm to 1.2ppm.

[0152] Further, step S752 is executed to determine whether the first concentration difference 0.1 ppm is within the interval range of -1.2 ppm to 1.2 ppm.

[0153] Through the steps in this embodiment, the first concentration and the second concentration are cross-validated, and the accuracy of the first concentration and the second concentration can be further detected in the second concentration range, and then corresponding measures are taken according to the first concentration and the second concentration to further confirm the reliability of the detection result, so as to avoid the occurrence of false alarms or wrong alarms of the transformer. Through steps S751 to S754, the accuracy of the gas infrared cross detection method is improved.

[0154] See also Fig. 9 In one embodiment, step S70, the step of detecting the operating state of the transformer according to the first concentration and the second concentration, further includes:

[0155] Step S761, if the cross-detection concentration is within the third concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a second concentration difference; the third concentration interval is an interval range greater than or equal to the second concentration threshold and less than the third concentration threshold;

[0156] Step S762, determining whether the second concentration difference is within a second difference range;

[0157] If yes, the operation state of the transformer is evaluated according to the maximum value of the first concentration and the second concentration, that is, step S742 is executed;

[0158] If not, continue to perform secondary gas infrared cross detection, that is, execute step S730.

[0159] In this embodiment, the third concentration threshold is 10ppm. The third concentration interval is an interval range greater than or equal to 5.0ppm and less than 10ppm. If the cross-detection concentration is within the third concentration interval, it can also be understood as being within 5.0ppm to 10ppm. The third concentration interval can be understood as a medium-high concentration interval. If the cross-detection concentration is within the third concentration interval, the second concentration difference formed by the first concentration and the second concentration is calculated. And further, the second concentration difference is judged.

[0160] If the second concentration difference is within the second difference range, step S763 is executed, and the process further jumps to steps S781 to S784 to further determine the warning state.

[0161] If the second concentration difference is not within the second difference range, step S764 is executed, and the process jumps to steps S791 to S795 to further determine the warning state. The description of step S764 may refer to the description of step S730 in the above embodiment.

[0162] In one embodiment, the second difference ranges from -30% of the minimum of the first concentration and the second concentration to +30% of the minimum of the first concentration and the second concentration.

[0163] Through the steps in this embodiment, the first concentration and the second concentration are cross-validated, and the accuracy of the first concentration and the second concentration can be further detected in the third concentration range, and then corresponding measures are taken according to the first concentration and the second concentration to further confirm the reliability of the detection result, so as to avoid the occurrence of false alarms or wrong alarms of the transformer. Through steps S761 to S764, the accuracy of the gas infrared cross detection method is improved.

[0164] See also Fig.10 In one embodiment, step S70, the step of detecting the operating state of the transformer according to the first concentration and the second concentration, further includes:

[0165] Step S771, if the cross-detection concentration is within the fourth concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a third concentration difference; the fourth concentration interval is an interval range greater than or equal to the third concentration threshold and less than the fourth concentration threshold;

[0166] Step S772, determining whether the third concentration difference is within a third difference range;

[0167] If yes, the operation state of the transformer is evaluated according to the maximum value of the first concentration and the second concentration, that is, step S742 is executed;

[0168] If not, continue to perform secondary gas infrared cross detection, that is, execute step S730.

[0169] In this embodiment, the fourth concentration threshold value may be 50.0ppm. The fourth concentration interval is a range from 10.0ppm to 50.0ppm. If the cross-detection concentration is within the fourth concentration interval, it may also be understood as being greater than or equal to 10.0ppm and less than 50.0ppm. The fourth concentration interval may be understood as a high concentration interval. If the cross-detection concentration is within the fourth concentration interval, the third concentration difference formed by the first concentration and the second concentration is calculated. Furthermore, the third concentration difference is judged.

[0170] If the third concentration difference is within the third difference range, step S773 is executed, and the process further jumps to steps S781 to S784 to further determine the warning state.

[0171] If the third concentration difference is not within the third difference range, step S774 is executed, and the process jumps to steps S791 to S795 to further determine the warning state. The description of step S774 may refer to the description of step S730 in the above embodiment.

[0172] In one embodiment, the third difference ranges from -20% of the minimum of the first concentration and the second concentration to +20% of the minimum of the first concentration and the second concentration.

[0173] Through the steps in this embodiment, the first concentration and the second concentration are cross-validated, and the accuracy of the first concentration and the second concentration can be further detected in the fourth concentration interval, and then corresponding measures are taken according to the first concentration and the second concentration to further confirm the reliability of the detection result to avoid the occurrence of false alarms or wrong alarms of the transformer. Through steps S771 to S774, the accuracy of the gas infrared cross detection method is improved.

[0174] In one embodiment, in step S742, the step of evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration includes:

[0175] Step S7421: if the maximum value of the first concentration and the second concentration is less than the first control threshold, the operating state of the transformer is normal operation, and the first concentration and the second concentration are sent to the user;

[0176] Alternatively, in step S7422, if the maximum value of the first concentration and the second concentration is greater than or equal to the first control threshold and less than the second control threshold, the operation state of the transformer is the first fault warning state, and the first fault warning state, the first concentration and the second concentration are sent to the user;

[0177] Alternatively, in step S7423, if the maximum value of the first concentration and the second concentration is greater than or equal to the second control threshold and less than the third control threshold, the operation state of the transformer is the second fault warning state, and the second fault warning state, the first concentration and the second concentration are sent to the user;

[0178] Alternatively, in step S7424, if the maximum value of the first concentration and the second concentration is greater than or equal to the third control threshold, the operating state of the transformer is an alarm state, and the alarm state, the first concentration and the second concentration are sent to the user.

[0179] In this embodiment, the first control threshold is 0.5ppm. In step S781, if the maximum value of the first concentration and the second concentration is less than the first control threshold, it indicates that the concentration of the measured gas is small, the transformer failure will not occur, and no personal injury and property loss will occur, that is, the transformer can continue to operate normally. In step S782, the second control threshold is 1.0ppm. The first fault warning state can be understood as informing the user to be alert and pay attention to the operating status of the currently working transformer every period of time (for example, 2 hours, 3 hours or 4 hours). In step S783, the third control threshold is 3.0ppm. The second fault warning state can be understood as informing the user to be alert and pay attention to the operating status of the currently working transformer in real time. In step S784, the alarm state sends the alarm state to the user, which attracts the user's high attention. The user shuts down the currently working transformer in time to avoid personal injury and property loss.

[0180] Through the steps in this embodiment, according to the comparison between the maximum value of the first concentration and the second concentration and different control thresholds, the operating state of the transformer can be divided into different degrees of states such as normal operation, the first fault warning state, the second fault warning state, and the alarm state, and the operating state of the transformer is fed back to the user in time, so that the user can take corresponding measures to the faulty transformer in time to avoid causing personal injury and property loss. At the same time, the first concentration and the second concentration are also sent to the user. The user can judge whether there are abnormal concentration values ​​in the first concentration and the second concentration based on the empirical value. Furthermore, the user can further make empirical judgments based on the specific values ​​of the received first concentration and the second concentration to avoid blindly taking countermeasures and causing unnecessary troubles to the user.

[0181] In one embodiment, after executing step S730 and continuing to perform secondary gas infrared cross detection, the method further includes:

[0182] Step S740, evaluating the operating state of the transformer according to the maximum value of the first re-measured concentration and the second re-measured concentration after the secondary gas infrared cross detection.

[0183] In this embodiment, the first re-measured concentration after the secondary gas infrared cross detection corresponds to the first concentration, which can be understood as a re-measurement of the first concentration. The second re-measured concentration after the secondary gas infrared cross detection corresponds to the second concentration, which can be understood as a re-measurement of the second concentration.

[0184] When evaluating the operating status of the transformer based on the maximum value of the first re-measured concentration and the second re-measured concentration after the secondary gas infrared cross detection, the evaluation method is the same as the relevant descriptions of steps S7421, S7422, S7423, and S7424 in the above embodiments, and reference may be made to the descriptions of the relevant steps in the above embodiments.

[0185] By performing a second retest of the abnormal concentration data in step S740 of this embodiment, the reliability of the data can be further confirmed. By performing a second gas infrared cross detection, the error caused by various factors in the initial detection can be reduced, and the reliability of the detection result can be further confirmed to avoid false alarms or wrong alarms of the transformer, so that the operating status of the transformer can be judged more accurately, allowing the user to take accurate countermeasures.

[0186] In one embodiment, after continuing to perform the step of secondary gas infrared cross detection in step S730, the method further includes:

[0187] Step S750, obtaining the absolute concentration increment of the transformer in normal operation within a preset interval period;

[0188] Step S761: if the absolute concentration increment is less than the first increment threshold, the operation state of the transformer within the preset interval period is normal operation;

[0189] Alternatively, in step S762, if the absolute concentration increment is greater than or equal to the first increment threshold and the absolute concentration increment is less than the second increment threshold, the operation state of the transformer within the preset interval period is the first fault warning state, and the first fault warning state is sent to the user;

[0190] Alternatively, in step S763, if the absolute concentration increment is greater than or equal to the second increment threshold and the absolute concentration increment is less than the third increment threshold, the operation state of the transformer within the preset interval period is the second fault warning state, and the second fault warning state is sent to the user;

[0191] Alternatively, in step S764, if the absolute concentration increment is greater than or equal to the third increment threshold, the operating state of the transformer within the preset interval period is an alarm state, and the alarm state is sent to the user.

[0192] In this embodiment, the preset interval period in step S750 can be understood as an interval of a period of time, such as an interval of one day, an interval of three days, an interval of one week, an interval of two weeks, or an interval of one month, and can be set according to the actual application scenario. For example: within a period of one week, the absolute increment of the measured gas concentration obtained when the transformer is in a normal operating state (which can also be understood as a stable operating state) is obtained. The absolute concentration increment can be an absolute concentration increment obtained by a near-infrared light detection method, or an absolute concentration increment obtained by a mid-infrared light detection method.

[0193] Furthermore, in step S761, step S762, step S763, and step S764, the absolute concentration increment is compared with the first increment threshold, the second increment threshold, and the third increment threshold, and the operating status of the transformer of different degrees is sent to the user, so that the user can take accurate countermeasures in time. In one embodiment, the first increment threshold is 0.30ppm. The second increment threshold is 0.60ppm. The third increment threshold is 1.20ppm.

[0194] In step S761, if the absolute concentration increment is less than the first increment threshold, it indicates that the concentration variation range of the measured gas is small, the fluctuation is small, and there will be no transformer failure, and no personal injury or property loss will be caused, that is, the transformer can continue to operate normally. In step S762, the first fault warning state can be understood as informing the user to be alert and pay attention to the operating status of the currently working transformer at intervals. In step S763, the second fault warning state can be understood as the user can be alert and pay real-time attention to the operating status of the currently working transformer. In step S764, the alarm status is sent to the user, which attracts the user's high attention. The user shuts down the currently working transformer in time to avoid personal injury and property loss.

[0195] Through the steps in this embodiment, according to the absolute concentration increment of the measured gas between two adjacent detections, it can be divided into different degrees of states such as normal operation, first fault warning state, second fault warning state, alarm state, etc., and the operating status of the transformer is fed back to the user in time, so that the user can take corresponding measures to the faulty transformer in time to avoid personal injury and property loss.

[0196] In one embodiment, the settings of various numerical values ​​of the first concentration threshold, the second concentration threshold, the third concentration threshold, the fourth concentration threshold, the first control threshold, the second control threshold, the third control threshold, the first incremental threshold, the second incremental threshold and the third incremental threshold in the above embodiments can be adjusted according to actual application scenarios and equipment. The specific numerical values ​​listed in the above embodiments are only used as examples to facilitate understanding of the solutions.

[0197] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0198] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0199] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0200] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0201] In the embodiments provided in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0202] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or 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.

[0203] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0204] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0205] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A gas infrared cross detection system, characterized in that: include: A cavity (10), wherein a first detection channel (113) and a second detection channel (114) are arranged in parallel and spaced apart from each other; A first photoacoustic receiving module (41) is installed in the first detection channel (113) and is used to receive a first photoacoustic signal formed by the interaction of near-infrared light in the first detection channel (113) with the gas to be detected, and convert the first photoacoustic signal into a first electrical signal; A first signal processing module (410), connected to the first photoacoustic receiving module (41), and configured to filter and amplify the first electrical signal to obtain a first detection signal; A second photoacoustic receiving module (42) is installed in the second detection channel (114) and is used to receive a second photoacoustic signal formed after the mid-infrared light in the second detection channel (114) interacts with the gas to be detected, and convert the second photoacoustic signal into a second electrical signal; A second signal processing module (420), connected to the second photoacoustic receiving module (42), and configured to filter and amplify the second electrical signal to obtain a second detection signal; a differential amplification module (50), connected to the first signal processing module (410) and the second signal processing module (420), respectively, and used to differentially amplify the first detection signal and the second detection signal to obtain a concentration detection signal; A main control module (70) is connected to the differential amplification module (50) and is used to determine the concentration of the gas being measured based on the concentration detection signal.

2. The gas infrared cross detection system according to claim 1, characterized in that: The system further comprises: The stable output module (60) is connected to the differential amplification module (50) and the main control module (70) respectively, and is used for filtering the concentration detection signal output by the differential amplification module (50) and transmitting the filtered signal to the main control module (70).

3. The gas infrared cross detection system according to claim 1, characterized in that: The first signal processing module (410) comprises a first filtering circuit (411) and a first preamplifier circuit (412); the first end of the first filtering circuit (411) is connected to the output end of the first photoacoustic receiving module (41); the second end of the first filtering circuit (411) is connected to the first end of the first preamplifier circuit (412); the first filtering circuit (411) is used to filter the first electrical signal to obtain a filtered first electrical signal; the second end of the first preamplifier circuit (412) is connected to the first end of the differential amplifier module (50) to amplify the filtered first electrical signal to obtain the first detection signal.

4. The gas infrared cross detection system according to any one of claims 1 to 3, characterized in that: The second signal processing module (420) comprises a second filtering circuit (421) and a second preamplifier circuit (422), wherein a first end of the second filtering circuit (421) is connected to an output end of the second photoacoustic receiving module (42), and a second end of the second filtering circuit (421) is connected to a first end of the second preamplifier circuit (422), and the second filtering circuit (421) is used to filter the second electrical signal to obtain a filtered second electrical signal; and a second end of the second preamplifier circuit (422) is connected to a second end of the differential amplifier module (50) to amplify the filtered second electrical signal to obtain the second detection signal.

5. A gas infrared cross detection method, characterized in that: Applied to the gas infrared cross detection system according to any one of claims 1 to 4, the gas infrared cross detection method comprises: Receiving a first photoacoustic signal formed by the interaction of near-infrared light and the measured gas, and converting the first photoacoustic signal into a first electrical signal; filtering and amplifying the first electrical signal to obtain a first detection signal; receiving a second photoacoustic signal formed by the interaction of the mid-infrared light and the measured gas, and converting the second photoacoustic signal into a second electrical signal; filtering and amplifying the second electrical signal to obtain a second detection signal; performing differential amplification on the first detection signal and the second detection signal to obtain a concentration detection signal; The concentration of the measured gas is determined according to the concentration detection signal.

6. The gas infrared cross detection method according to claim 5, characterized in that: The step of determining the concentration of the measured gas according to the concentration detection signal comprises: Determine the first concentration of the measured gas according to the first concentration detection signal; the first concentration detection signal is determined after differential amplification based on the first detection signal as the detection signal and the second detection signal as the reference signal; Determine the second concentration of the measured gas according to the second concentration detection signal; the second concentration detection signal is determined after differential amplification based on the second detection signal as a detection signal and the first detection signal as a reference signal; After the step of determining the concentration of the measured gas according to the concentration detection signal, the method further comprises: The operating state of the transformer is detected according to the first concentration and the second concentration.

7. The gas infrared cross detection method according to claim 6, characterized in that: The step of detecting the operating state of the transformer according to the first concentration and the second concentration includes: Determining whether the first concentration is within a standard range of the discrete data group to which it belongs, and whether the second concentration is within a standard range of the discrete data group to which it belongs; If yes, performing weighted average processing on the first concentration and the second concentration to obtain a cross detection concentration, and determining a concentration interval corresponding to the cross detection concentration according to the cross detection concentration; If not, continue to perform secondary gas infrared cross detection.

8. The gas infrared cross detection method according to claim 7, characterized in that: The step of detecting the operating state of the transformer according to the first concentration and the second concentration further includes: If the cross-detection concentration is within a first concentration interval, determining whether the first concentration and the second concentration are both less than a first threshold; the first concentration interval is a range of intervals less than the first concentration threshold; If yes, evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration; If not, continue to perform secondary gas infrared cross detection.

9. The gas infrared cross detection method according to claim 7, characterized in that: The step of detecting the operating state of the transformer according to the first concentration and the second concentration further includes: If the cross-detection concentration is within a second concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a first concentration difference; the second concentration interval is an interval range greater than or equal to the first concentration threshold and less than the second concentration threshold; determining whether the first concentration difference is within a first difference range; If yes, evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration; If not, continue to perform secondary gas infrared cross detection.

10. The gas infrared cross detection method according to claim 7, characterized in that: The step of detecting the operating state of the transformer according to the first concentration and the second concentration further includes: If the cross-detection concentration is within a third concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a second concentration difference; the third concentration interval is an interval range greater than or equal to the second concentration threshold and less than the third concentration threshold; determining whether the second concentration difference is within a second difference range; If yes, evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration; If not, continue to perform secondary gas infrared cross detection.

11. The gas infrared cross detection method according to claim 7, characterized in that: The step of detecting the operating state of the transformer according to the first concentration and the second concentration further includes: If the cross-detection concentration is within a fourth concentration interval, the difference between the first concentration and the second concentration is calculated to obtain a third concentration difference; the fourth concentration interval is an interval range greater than or equal to the third concentration threshold and less than the fourth concentration threshold; determining whether the third concentration difference is within a third difference range; If yes, evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration; If not, continue to perform secondary gas infrared cross detection.

12. The gas infrared cross detection method according to any one of claims 8 to 11, characterized in that: The step of evaluating the operating state of the transformer according to the maximum value of the first concentration and the second concentration comprises: If the maximum value of the first concentration and the second concentration is less than the first control threshold, the operating state of the transformer is normal operation, and the first concentration and the second concentration are sent to the user; Alternatively, if the maximum value of the first concentration and the second concentration is greater than or equal to the first control threshold and less than the second control threshold, the operating state of the transformer is a first fault warning state, and the first fault warning state, the first concentration and the second concentration are sent to the user; Alternatively, if the maximum value of the first concentration and the second concentration is greater than or equal to the second control threshold and less than the third control threshold, the operating state of the transformer is the second fault warning state, and the second fault warning state, the first concentration and the second concentration are sent to the user; Alternatively, if the maximum value of the first concentration and the second concentration is greater than or equal to the third control threshold, the operating state of the transformer is an alarm state, and the alarm state, the first concentration and the second concentration are sent to the user.

13. The gas infrared cross detection method according to any one of claims 8 to 11, characterized in that: After the step of continuing to perform the secondary gas infrared cross detection, the method further includes: The operating state of the transformer is evaluated according to the maximum value of the first re-measured concentration and the second re-measured concentration after the secondary gas infrared cross detection.

14. The gas infrared cross detection method according to any one of claims 8 to 11, characterized in that: After the step of continuing to perform the secondary gas infrared cross detection, the method further includes: Within a preset interval period, obtaining the absolute concentration increment of the transformer under normal operating conditions; If the absolute concentration increment is less than the first increment threshold, the operating state of the transformer in the preset interval period is normal operation; Alternatively, if the absolute concentration increment is greater than or equal to the first increment threshold and the absolute concentration increment is less than the second increment threshold, the operation state of the transformer within the preset interval period is a first fault warning state, and the first fault warning state is sent to the user; Alternatively, if the absolute concentration increment is greater than or equal to the second increment threshold and the absolute concentration increment is less than the third increment threshold, the operation state of the transformer within the preset interval period is a second fault warning state, and the second fault warning state is sent to the user; Alternatively, if the absolute concentration increment is greater than or equal to the third increment threshold, the operating state of the transformer within the preset interval period is an alarm state, and the alarm state is sent to the user.

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