Gas concentration detection method, device, system and storage medium

Abstract

The present invention discloses a gas concentration detection method, device, system, and storage medium. The method comprises obtaining the laser energy value of a first laser beam after attenuation by a target gas to be detected, adjusting the attenuation state of a second laser beam so that the laser energy values ​​of the first and second laser beams are the same after attenuation; obtaining a photoelectric signal resulting from interference between the attenuated first and second laser beams; and, based on the photoelectric signal, performing phase adjustment on the first and second laser beams to minimize the value of the photoelectric signal after interference; and determining the concentration of the target gas based on the gas absorption signal spectrum of the phase-adjusted second laser beam. The present invention constructs an absorption optical path and a reference optical path, respectively, with the first and second laser beams, and adjusts the phase of the interference photoelectric signal between the absorption and reference optical paths to obtain a gas absorption signal spectrum free of background signals to achieve gas concentration detection. This solves the current technical problem of low accuracy in optical gas concentration detection.

Description

Technical Field

[0001] The present invention relates to the field of gas detection technology, and in particular to a gas concentration detection method, device, system and storage medium. Background Art

[0002] The specific process of measuring the target gas concentration in the TDLAS (Tunable Diode Laser Absorption Spectroscopy) detection system is as follows: a sawtooth wave tuning signal is loaded onto the laser current driver via a signal generator. Due to the effect of the tuning signal, the wavelength emitted by the laser changes with the sawtooth wave, completing the scanning of the target gas. Due to the absorption of light by the target gas, the transmitted light contains the absorption information of the target gas, and an absorption spectrum containing absorption information can be obtained. Generally, the non-absorbent portions of the gas at both ends of the absorption spectrum are extracted and fitted into an original absorption spectrum before being absorbed by the gas. The extracted photoelectric signal is divided by the fitted original absorption spectrum to deduct the background information and obtain the gas absorption spectrum. The gas concentration information can be deduced from the gas absorption spectrum.

[0003] During this derivation process, the useful information about the derivatized gas concentration is the portion absorbed by the gas. When the gas concentration is low or the spectral absorption is low, this data is very small and is superimposed on the photoelectric signal background. The photoelectric detection signal itself has a certain amount of detection noise due to thermal noise and defects in the photoelectric device, and the noise amplitude is related to the photoelectric signal intensity. The tiny absorption signal is submerged in the background information, causing the deduced absorption information to be superimposed with a strong signal noise. This is also one of the bottlenecks of the low accuracy of TDLAS detection at low concentrations. Existing TDLAS detection methods, whether based on direct absorption or harmonic detection methods, are affected by the background signal noise. Regardless of whether a higher-precision amplifier, a higher-precision ADC, or a faster detection frequency is used in the future, the noise introduced by the background signal will be proportionally amplified, and this problem cannot be fundamentally solved. Therefore, how to improve the accuracy of optical gas concentration detection is a technical problem that needs to be solved urgently.

[0004] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of the present invention is to provide a gas concentration detection method, device, system and storage medium, aiming to solve the technical problem of low accuracy of current optical gas concentration detection.

[0006] To achieve the above object, the present invention provides a gas concentration detection method for use in a gas concentration detection device, the method comprising the following steps:

[0007] Acquiring a laser energy value of the first laser beam after attenuation by the target gas to be detected;

[0008] adjusting the attenuation state of the second laser beam according to the laser energy value so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same;

[0009] Acquire a photoelectric signal resulting from interference between the attenuated first laser beam and the second laser beam, and adjust the phases of the first laser beam and the second laser beam based on the photoelectric signal to minimize a value of the photoelectric signal resulting from interference;

[0010] The concentration of the target gas is determined based on the gas absorption signal spectrum of the second laser beam after phase adjustment.

[0011] Optionally, the first laser beam and the second laser beam are obtained by splitting an original laser beam generated by a laser using a beam splitter.

[0012] Optionally, the adjusting the attenuation state of the second laser beam is specifically: controlling an optical attenuator acting on the second laser beam to adjust the attenuation state of the second laser beam.

[0013] Optionally, the phase adjustment of the first laser beam and the second laser beam is specifically: controlling a phase adjustment device acting on the first laser beam and the second laser beam to adjust the phase of the first laser beam and the second laser beam.

[0014] Optionally, the phase adjustment device connects a first optical fiber for transmitting the first laser beam and a second optical fiber for transmitting the second laser beam; the control of the phase adjustment device acting on the first laser beam and the second laser beam performs a phase adjustment step on the first laser beam and the second laser beam, specifically: controlling the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber to perform phase adjustment on the first laser beam and the second laser beam.

[0015] Optionally, the step of controlling the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber is specifically: controlling the limit adjustment device to adjust the temperature of the first optical fiber and the second optical fiber to change the optical path difference between the first optical fiber and the second optical fiber.

[0016] Optionally, the step of determining the concentration of the target gas based on the gas absorption signal spectrum of the second laser beam after phase adjustment is specifically as follows:

[0017] receiving a photoelectric detection signal of the second laser beam from a detector, and acquiring a gas absorption signal spectrum line of the second laser beam based on the photoelectric detection signal;

[0018] Based on the gas absorption signal spectrum, the concentration of the target gas is obtained by inverse derivation.

[0019] In addition, in order to achieve the above-mentioned object, the present invention further provides a gas concentration detection device, the gas concentration detection device comprising:

[0020] an acquisition module, configured to acquire a laser energy value of the first laser beam after attenuation by the target gas to be detected;

[0021] an adjusting module, configured to adjust the attenuation state of the second laser beam according to the laser energy value, so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same;

[0022] an adjustment module, configured to obtain a photoelectric signal resulting from interference between the attenuated first laser beam and the second laser beam, and perform phase adjustment on the first laser beam and the second laser beam based on the photoelectric signal to minimize a value of the photoelectric signal resulting from interference;

[0023] The determination module is used to determine the concentration of the target gas based on the gas absorption signal spectrum line of the second laser beam after phase adjustment.

[0024] Optionally, the adjustment module is further configured to control a phase adjustment device acting on the first laser beam and the second laser beam to adjust the phases of the first laser beam and the second laser beam.

[0025] Optionally, the phase adjustment device connects a first optical fiber for transmitting the first laser beam and a second optical fiber for transmitting the second laser beam; the adjustment module is also used to control the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber to perform phase adjustment on the first laser beam and the second laser beam.

[0026] Optionally, the adjustment module is further configured to control the limit adjustment device to adjust the temperature of the first optical fiber and the second optical fiber, so as to change the optical path difference between the first optical fiber and the second optical fiber.

[0027] In addition, in order to achieve the above-mentioned object, the present invention also provides a gas concentration detection system, the system comprising:

[0028] a gas concentration detection component configured to generate a first laser beam and a second laser beam, emit the first laser beam to a target gas to be detected, perform phase adjustment and interference detection on the first laser beam that has passed through the target gas to be detected and the attenuated second laser beam, and obtain a gas absorption signal spectrum corresponding to the second laser beam when the photoelectric signal value after interference is minimum;

[0029] A gas concentration detection device comprises: a memory, a processor, and a gas concentration detection program stored in the memory and executable on the processor, wherein the gas concentration detection program implements the steps of the gas concentration detection method described above when executed by the processor.

[0030] Optionally, the gas concentration detection component includes a laser and a beam splitter, the laser is used to emit original laser light, and the beam splitter is used to split the original laser light to obtain a first laser beam and a second laser beam.

[0031] Optionally, the gas concentration detection component includes an optical attenuator, and the optical attenuator is used to attenuate the second laser beam.

[0032] Optionally, the gas concentration detection component includes a phase adjustment device, which is provided with a temperature adjustment part, and the first optical fiber for transmitting the first laser beam and the second optical fiber for transmitting the second laser beam are fixed to the temperature adjustment part for phase adjustment of the first laser beam and the second laser beam.

[0033] Optionally, the temperature adjustment unit acts on an optical path of the first optical fiber that is different from the optical path of the second optical fiber, and when the temperature adjustment unit performs temperature adjustment, the optical path difference between the first optical fiber and the second optical fiber is changed.

[0034] Optionally, the gas concentration detection component includes a detector, which is used to detect the interference signal between the first laser beam and the second laser beam, and obtain the gas absorption signal spectrum line corresponding to the second laser beam when the photoelectric signal value after interference is minimum.

[0035] In addition, in order to achieve the above-mentioned purpose, the present invention also provides a storage medium, on which a gas concentration detection program is stored. When the gas concentration detection program is executed by a processor, the steps of the gas concentration detection method described above are implemented.

[0036] Embodiments of the present invention provide a gas concentration detection method, device, system, and storage medium. The method comprises obtaining the laser energy value of a first laser beam after attenuation by a target gas to be detected; adjusting the attenuation state of a second laser beam based on the laser energy value so that the laser energy values ​​of the first and second laser beams after attenuation are the same; obtaining a photoelectric signal resulting from interference between the attenuated first and second laser beams; and, based on the photoelectric signal, performing phase adjustment on the first and second laser beams to minimize the value of the interference photoelectric signal; and determining the concentration of the target gas based on the gas absorption signal spectrum of the phase-adjusted second laser beam. The present invention constructs an absorption optical path and a reference optical path, respectively, with the first and second laser beams, and adjusts the phase of the interference photoelectric signal between the absorption and reference optical paths to obtain a gas absorption signal spectrum free of background signals for gas concentration detection. This addresses the current technical problem of low accuracy in optical gas concentration detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the structure of a gas concentration detection system in an embodiment of the present invention.

[0038] Figure 2 Schematic diagram of the structure of a gas concentration detection device in an embodiment of the present invention.

[0039] Figure 3 Schematic diagram of a gas concentration detection method according to an embodiment of the present invention.

[0040] Figure 4 This is a structural block diagram of a gas concentration detection device in an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 1-gas concentration detection equipment; 2-gas concentration detection component; 201-laser; 202-beam splitter; 203-optical attenuator; 204-phase adjustment device; 205-detector.

[0043] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0044] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] Existing optical gas concentration detection methods are affected by background signal noise. Regardless of whether a higher-precision amplifier, a higher-precision ADC, or a faster detection frequency is used, the noise introduced by the background signal will be proportionally amplified, and the problem cannot be fundamentally solved.

[0046] To address this issue, various embodiments of the gas concentration detection method of the present invention are provided. The method utilizes a first laser beam and a second laser beam to construct an absorption optical path and a reference optical path, respectively. The method adjusts the phase of the interfering photoelectric signals from the absorption and reference optical paths to obtain a background-free gas absorption signal spectrum for gas concentration detection. This method addresses the current technical issue of low accuracy in optical gas concentration detection.

[0047] The embodiment of the present invention provides a gas concentration detection system, referring to Figure 1 , Figure 1 Schematic diagram of the structure of the gas concentration detection system involved in the embodiment of the present invention.

[0048] In this embodiment, the gas concentration detection system includes a gas concentration detection device 1 and a gas concentration detection component 2 .

[0049] It should be noted that the gas concentration detection component 2 is used to generate a first laser beam and a second laser beam, emit the first laser beam to the target gas to be detected, perform phase adjustment and interference detection on the first laser beam passing through the target gas to be detected and the attenuated second laser beam, and obtain the gas absorption signal spectrum line corresponding to the first laser beam when the photoelectric signal value after interference is the minimum.

[0050] In a preferred embodiment, the gas concentration detection component 2 includes a laser 201 and a beam splitter 202. The laser 201 is used to emit original laser light, and the beam splitter 202 is used to split the original laser light to obtain a first laser beam and a second laser beam.

[0051] It is easy to understand that in order to construct the absorption optical path and the reference optical path, the laser 201 is first controlled to emit a constant optical power laser, and then the constant optical power laser is split using the beam splitter 202, thereby obtaining a first laser beam and a second laser beam of the same wavelength emitted by the same laser source, thereby providing homologous lasers for constructing the absorption optical path and the reference optical path.

[0052] In a preferred embodiment, the gas concentration detection component 2 includes an optical attenuator 203, and the optical attenuator 203 is used to attenuate the second laser beam.

[0053] As will be readily understood, after obtaining the first and second laser beams, the first laser beam undergoes phase adjustment after passing through the target gas to be detected, while the second laser beam undergoes phase adjustment after passing through optical attenuator 203. Adjusting optical attenuator 203 ensures that the attenuated optical energies of the first and second laser beams are equal. Consequently, optical attenuator 203 can eliminate the difference in optical energy between the absorption light path and the reference light path caused by the attenuation of the absorption light path when passing through the target gas to be detected, thereby eliminating the background signal and improving the interference effect.

[0054] The specific operation is: first detect the photoelectric signal intensity of the absorption light path after passing through the target gas to be detected, then cut off the absorption light path, connect to the reference light path, and adjust the optical attenuator 203 so that the photoelectric signal intensity of the reference light path after passing through the optical attenuator is the same as the photoelectric signal intensity of the absorption light path.

[0055] In a preferred embodiment, the gas concentration detection component 2 includes a phase adjustment device 204, and the phase adjustment device 204 is provided with a temperature adjustment part. The first optical fiber for transmitting the first laser beam and the second optical fiber for transmitting the second laser beam are fixed to the temperature adjustment part for phase adjustment of the first laser beam and the second laser beam.

[0056] It is easy to understand that the first laser beam attenuated by the target gas to be detected and the second laser beam attenuated by the optical attenuator 203 need to be input into the phase adjustment device 204 to adjust the phases of the first laser beam and the second laser beam.

[0057] Specifically, the phase adjustment device 204 is provided with a temperature adjustment unit, which can change the temperature according to the adjustment instruction. Thus, the first optical fiber used to transmit the first laser beam and the second optical fiber used to transmit the second laser beam are fixed to the temperature adjustment unit. The temperature of the first optical fiber and the second optical fiber can be changed by the temperature adjustment unit, thereby performing phase adjustment on the first laser beam and the second laser beam.

[0058] It should be noted that the temperature regulating unit can be configured with a built-in semiconductor cooling chip and temperature control circuit to precisely control its own temperature upon receiving adjustment instructions. Based on this, the first and second optical fibers are closely attached to the inner wall of the temperature regulating unit. When the temperature of the temperature regulating unit changes, the optical path length within the optical fibers changes due to the principle of thermal expansion and contraction, which in turn affects the phase difference between the two beams at the light output position.

[0059] It is easy to understand that the optical path of the first optical fiber acted upon by the temperature adjustment unit is different from the optical path of the second optical fiber acted upon by the temperature adjustment unit. When the temperature adjustment unit performs temperature adjustment, the optical path difference between the first optical fiber and the second optical fiber is changed.

[0060] Specifically, by controlling the different contact lengths between the first and second optical fibers and the temperature control unit, the phase difference between the first laser beam within the first optical fiber and the second laser beam within the second optical fiber can be adjusted when the temperature of the temperature control unit changes. In this embodiment, the second optical fiber corresponding to the reference optical path is configured to have a longer contact length with the temperature control unit than the first optical fiber, thereby adjusting the phase difference between the first and second laser beams during temperature adjustment.

[0061] When performing phase adjustment, the temperature of the temperature regulating unit is controlled so that the phase difference between the first laser beam and the second laser beam satisfies the change in the interference fringe ring during detection until the photoelectric signal value after interference is minimum. At this time, the temperature is set as the optimal temperature for phase adjustment and maintained unchanged.

[0062] In a preferred embodiment, the gas concentration detection component 2 includes a detector 205, which is used to detect the interference signal between the first laser beam and the second laser beam, and obtain the gas absorption signal spectrum line corresponding to the second laser beam when the photoelectric signal value after interference is minimum.

[0063] Specifically, after a portion of the light energy in the absorption light path is absorbed by the gas, it interferes with the coherent light in the reference light path. The resulting dark fringes vary with the absorption intensity. At the optimal temperature, the center of detector 205 is located at a dark spot, manifested by a detection signal close to zero.

[0064] It is easy to understand that the light signal in the absorption light path will attenuate after being absorbed by the gas, while the signal in the reference light path does not change at this time. The detector 205 obtains the original detection signal. After amplification, the absorption signal will obtain a gas absorption signal spectrum without background signal. Due to the absence of background signal and its noise interference, the signal-to-noise ratio of the absorption signal will be greatly improved under the same detection conditions.

[0065] Based on this, when the gas concentration detection device 1 obtains the gas absorption signal spectrum corresponding to the second laser beam when the photoelectric signal value after interference is the minimum, the gas concentration can be deduced by detecting the absorption signal minus the background and combining it with the TDLAS general detection method.

[0066] Reference Figure 2 , Figure 2 Schematic diagram of a gas concentration detection device 1 according to an embodiment of the present invention.

[0067] The device can be a user equipment (UE) such as a mobile phone, smart phone, laptop computer, digital broadcast receiver, personal digital assistant (PDA), tablet computer (PAD), handheld device, vehicle-mounted device, wearable device, computing device or other processing device connected to a wireless modem, mobile station (MS), etc. The device may be called a user terminal, portable terminal, desktop terminal, etc.

[0068] Typically, the device includes: at least one processor 301, a memory 302, and a gas concentration detection program stored in the memory and executable on the processor, wherein the gas concentration detection program is configured to implement the steps of the gas concentration detection method as described above.

[0069] The processor 301 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 301 may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), or PLA (Programmable Logic Array). The processor 301 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 301 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. The processor 301 may also include an AI (Artificial Intelligence) processor, which is used to process gas concentration detection operations, so that the gas concentration detection model can be trained and learned autonomously to improve efficiency and accuracy.

[0070] Memory 302 may include one or more computer-readable storage media, which may be non-transitory. Memory 302 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in memory 302 is used to store at least one instruction, which is executed by processor 301 to implement the gas concentration detection method provided in the method embodiment of the present application.

[0071] In some embodiments, the terminal may optionally include a communication interface 303 and at least one peripheral device. The processor 301, memory 302, and communication interface 303 may be connected via a bus or signal lines. Each peripheral device may be connected to the communication interface 303 via a bus, signal lines, or circuit boards. Specifically, the peripheral device may include at least one of a radio frequency circuit 304, a display screen 305, and a power supply 306.

[0072] The communication interface 303 can be used to connect at least one peripheral device related to I / O (Input / Output) to the processor 301 and the memory 302. The communication interface 303 is used to receive the movement trajectories and other data of multiple mobile terminals uploaded by users through the peripheral device. In some embodiments, the processor 301, the memory 302, and the communication interface 303 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 301, the memory 302, and the communication interface 303 can be implemented on a separate chip or circuit board, which is not limited in this embodiment.

[0073] The RF circuit 304 is used to receive and transmit RF (Radio Frequency) signals, also known as electromagnetic signals. The RF circuit 304 communicates with communication networks and other communication devices via electromagnetic signals, thereby acquiring the movement trajectories and other data of multiple mobile terminals. The RF circuit 304 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals. Optionally, the RF circuit 304 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, and the like. The RF circuit 304 can communicate with other terminals via at least one wireless communication protocol. Such wireless communication protocols include, but are not limited to, metropolitan area networks, various generations of mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and / or WiFi (Wireless Fidelity) networks. In some embodiments, the RF circuit 304 may also include circuits related to NFC (Near Field Communication), which is not limited in this application.

[0074] Display screen 305 is used to display a UI (User Interface). This UI may include graphics, text, icons, videos, or any combination thereof. When display screen 305 is a touch screen display, it is also capable of collecting touch signals on or above the surface of display screen 305. This touch signal can be input as a control signal to processor 301 for processing. In this case, display screen 305 can also be used to provide virtual buttons and / or a virtual keyboard, also known as soft buttons and / or a soft keyboard. In some embodiments, display screen 305 can be a single display screen, the front panel of the electronic device; in other embodiments, display screen 305 can be at least two, each disposed on different surfaces of the electronic device or in a foldable design; in still other embodiments, display screen 305 can be a flexible display screen, disposed on a curved or foldable surface of the electronic device. Display screen 305 can also be configured as a non-rectangular irregular shape, i.e., a special-shaped screen. Display screen 305 can be made of materials such as LCD (Liquid Crystal Display) and OLED (Organic Light-Emitting Diode).

[0075] Power supply 306 is used to power various components in the electronic device. Power supply 306 can be AC ​​power, DC power, a disposable battery, or a rechargeable battery. When power supply 306 includes a rechargeable battery, the rechargeable battery can support wired charging or wireless charging. The rechargeable battery can also be used to support fast charging technology.

[0076] Those skilled in the art will understand that Figure 2 The structure shown in the figure does not constitute a limitation on the gas concentration detection device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0077] The embodiment of the present invention provides a method for detecting gas concentration. Figure 3 , Figure 3 Schematic diagram of the gas concentration detection method embodiment of the present invention.

[0078] In this embodiment, the gas concentration detection method is based on the above-mentioned gas concentration detection system, and includes the following steps:

[0079] Step S100 , obtaining the laser energy value of the first laser beam after attenuation by the target gas to be detected.

[0080] Specifically, when constructing the absorption optical path and the reference optical path, the laser is first controlled to emit a constant optical power laser, and then the constant optical power laser is split using a beam splitter, thereby obtaining a first laser beam and a second laser beam of the same wavelength emitted by the same laser source, thereby providing homologous lasers for constructing the absorption optical path and the reference optical path.

[0081] On this basis, in order to eliminate the light energy difference between the signal in the absorption light path that is attenuated after passing through the target gas to be detected and the signal in the reference light path, so as to eliminate the base signal and improve the interference effect, it is necessary to set the light energy of the first laser beam and the second laser beam of the input phase adjustment device to be equal.

[0082] The specific operation is: first detect the photoelectric signal intensity of the absorption light path after passing through the target gas to be detected, then cut off the absorption light path, connect to the reference light path, and adjust the optical attenuator so that the photoelectric signal intensity of the reference light path after passing through the optical attenuator is the same as the photoelectric signal intensity of the absorption light path.

[0083] Therefore, in this embodiment, it is necessary to first determine the laser energy value of the first laser beam after passing through the target gas to be detected, so as to control the second laser beam to match the light energy of the first laser beam.

[0084] Step S200 : adjusting the attenuation state of the second laser beam according to the laser energy value so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same.

[0085] Specifically, after obtaining the first and second laser beams, the first laser beam is passed through the target gas to be detected and then phase-adjusted. The second laser beam is passed through an optical attenuator and then phase-adjusted. During attenuation adjustment, an optical attenuator is placed in the reference light path and adjusted to ensure that the attenuated optical energies of the first and second laser beams are equal.

[0086] It should be noted that in order to ensure the homology of the first laser beam and the second laser beam, when constructing the absorption optical path and the reference optical path, the laser is first controlled to emit a constant optical power laser, and then the constant optical power laser is split using a beam splitter, thereby obtaining the first laser beam and the second laser beam of the same wavelength emitted by the same laser source, thereby providing homologous lasers for constructing the absorption optical path and the reference optical path.

[0087] Step S300 : Acquire a photoelectric signal after interference between the attenuated first laser beam and the second laser beam, and adjust the phases of the first laser beam and the second laser beam based on the photoelectric signal to minimize the photoelectric signal value after interference.

[0088] Specifically, the phases of the first laser beam and the second laser beam are adjusted by controlling a phase adjustment device acting on the first laser beam and the second laser beam to adjust the phases of the first laser beam and the second laser beam.

[0089] It is easy to understand that after part of the light energy in the absorption light path is absorbed by the gas, it interferes with the coherent light in the reference light path. The dark fringes formed by the interference change with the absorption intensity. By adjusting the phase of the first laser beam and the second laser beam to minimize the photoelectric signal value after the interference, that is, the interference fringe ring changes, and the center position will be at a dark spot, which manifests as the detector detection signal close to 0.

[0090] In a preferred embodiment, the phase adjustment device connects a first optical fiber for transmitting the first laser beam and a second optical fiber for transmitting the second laser beam.

[0091] Thus, the phase adjustment device acting on the first laser beam and the second laser beam is controlled to perform phase adjustment steps on the first laser beam and the second laser beam, specifically: the phase adjustment device is controlled to adjust the optical path of the first optical fiber and the second optical fiber to perform phase adjustment on the first laser beam and the second laser beam.

[0092] It should be noted that the optical path of the first optical fiber for transmitting the first laser beam and the second optical fiber for transmitting the second laser beam fixed thereon can be adjusted by a temperature adjustment part provided in the phase adjustment device. According to the principle of thermal expansion and contraction, the optical path in the optical fiber changes, thereby affecting the phase difference between the two beams of light at the light output position.

[0093] On this basis, the step of controlling the phase adjustment device to adjust the optical path lengths of the first and second optical fibers specifically comprises controlling the limit adjustment device to adjust the temperature of the first and second optical fibers to change the optical path length difference between the first and second optical fibers. During phase adjustment, the temperature of the temperature adjustment unit is controlled so that the phase difference between the first and second laser beams satisfies the change in the interference fringe rings observed during detection, until the photoelectric signal value after interference is minimized. At this point, this temperature is set as the optimal temperature for phase adjustment and maintained constant.

[0094] Step S400 , determining the concentration of the target gas based on the gas absorption signal spectrum of the second laser beam after phase adjustment.

[0095] Specifically, a photoelectric detection signal of the second laser beam is received by a detector, and a gas absorption signal spectrum of the second laser beam is obtained based on the photoelectric detection signal; and the concentration of the target gas is obtained by reverse derivation based on the gas absorption signal spectrum.

[0096] It is easy to understand that, under the premise of maintaining the optimal temperature of the phase adjustment device, by receiving the photoelectric detection signal of the second laser beam in the reference light path from the detector, a gas absorption signal spectrum without background signal will be obtained after amplification of the absorption signal. Due to the absence of background signal and its noise interference, the signal-to-noise ratio of the absorption signal will be greatly improved under the same detection conditions. By detecting the absorption signal with the background subtracted, the gas concentration can be deduced in combination with the general TDLAS detection method.

[0097] In this embodiment, a gas concentration detection method is provided. An absorption light path and a reference light path are constructed by a first laser beam and a second laser beam, respectively. The phases of the interfering photoelectric signals of the absorption light path and the reference light path are adjusted to obtain a gas absorption signal spectrum without a background signal to realize gas concentration detection. This solves the technical problem of low accuracy of current optical gas concentration detection.

[0098] The embodiment of the present invention provides a gas concentration detection device, referring to Figure 4 , Figure 4 This is a structural block diagram of an embodiment of a gas concentration detection device of the present invention.

[0099] like Figure 4 As shown, the gas concentration detection device proposed in the embodiment of the present invention includes:

[0100] An acquisition module 10 is used to acquire the laser energy value of the first laser beam after attenuation by the target gas to be detected;

[0101] an adjusting module 20, configured to adjust the attenuation state of the second laser beam according to the laser energy value, so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same;

[0102] an adjustment module 30, configured to obtain a photoelectric signal resulting from interference between the attenuated first laser beam and the second laser beam, and perform phase adjustment on the first laser beam and the second laser beam based on the photoelectric signal to minimize a value of the photoelectric signal resulting from interference;

[0103] The determination module 40 is configured to determine the concentration of the target gas based on the gas absorption signal spectrum of the second laser beam after phase adjustment.

[0104] As an embodiment, the adjustment module 20 is further configured to control a phase adjustment device acting on the first laser beam and the second laser beam to adjust the phases of the first laser beam and the second laser beam.

[0105] As an embodiment, the phase adjustment device connects a first optical fiber for transmitting a first laser beam and a second optical fiber for transmitting a second laser beam; the adjustment module 20 is also used to control the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber to perform phase adjustment on the first laser beam and the second laser beam.

[0106] As an embodiment, the adjustment module 20 is further configured to control the limit adjustment device to adjust the temperature of the first optical fiber and the second optical fiber to change the optical path difference between the first optical fiber and the second optical fiber.

[0107] In this embodiment, a gas concentration detection device is provided. An absorption light path and a reference light path are respectively constructed by a first laser beam and a second laser beam. The phases of the interfering photoelectric signals of the absorption light path and the reference light path are adjusted to obtain a gas absorption signal spectrum without a background signal to realize gas concentration detection. This solves the technical problem of low accuracy of current optical gas concentration detection.

[0108] Other embodiments or specific implementations of the gas concentration detection device of the present invention can refer to the above-mentioned method and system embodiments, which will not be repeated here.

[0109] In addition, an embodiment of the present invention further proposes a storage medium on which a gas concentration detection program is stored, and when the gas concentration detection program is executed by a processor, the steps of the gas concentration detection method described above are implemented. Therefore, no further description will be given here. In addition, the description of the beneficial effects of adopting the same method will not be repeated. For technical details not disclosed in the computer-readable storage medium embodiment involved in this application, please refer to the description of the method embodiment of this application. As an example, the program instructions can be deployed to be executed on one computing device, or on multiple computing devices located at one location, or on multiple computing devices distributed at multiple locations and interconnected by a communication network.

[0110] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware through a computer program. The above-described program can be stored in a computer-readable storage medium. When executed, the program can include the processes in the above-described method embodiments. The above-described storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0111] It should also be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive effort.

[0112] Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware, and of course can also be implemented by means of dedicated hardware including application-specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components, etc. In general, all functions performed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structures used to implement the same function can also be diverse, such as analog circuits, digital circuits, or dedicated circuits. However, for the present invention, software program implementation is a better implementation method in most cases. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc., and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

Claims

1. A gas concentration detection method, characterized in that: For use in gas concentration detection equipment, the method comprises the following steps: Acquiring a laser energy value of the first laser beam after attenuation by the target gas to be detected; adjusting the attenuation state of the second laser beam according to the laser energy value so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same; Acquire a photoelectric signal after interference between the attenuated first laser beam and the second laser beam, and perform phase adjustment on the first laser beam and the second laser beam based on the photoelectric signal, specifically by controlling a phase adjustment device acting on the first laser beam and the second laser beam to perform phase adjustment on the first laser beam and the second laser beam, specifically by controlling the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber, specifically by controlling the limit adjustment device to adjust the temperature of the first optical fiber and the second optical fiber to change the optical path difference between the first optical fiber and the second optical fiber, so as to perform phase adjustment on the first laser beam and the second laser beam to minimize the value of the photoelectric signal after interference, wherein the phase The phase adjustment device connects a first optical fiber for transmitting a first laser beam and a second optical fiber for transmitting a second laser beam, wherein the first optical fiber and the second optical fiber achieve phase difference adjustment of the first laser beam in the first optical fiber and the second laser beam in the second optical fiber when the temperature of the temperature adjustment part changes by controlling the different contact lengths between the first optical fiber and the second optical fiber; the contact length of the second optical fiber with the temperature adjustment part is longer than that of the first optical fiber; when performing phase adjustment, the temperature of the temperature adjustment part is controlled so that the phase difference between the first laser beam and the second laser beam satisfies the change in the interference fringe ring during detection, until the photoelectric signal value after interference is minimized, and the temperature is set as the optimal temperature for phase adjustment and maintained unchanged; The concentration of the target gas is determined based on the gas absorption signal spectrum of the second laser beam after phase adjustment.

2. The gas concentration detection method according to claim 1, wherein: The first laser beam and the second laser beam are obtained by splitting an original laser beam generated by a laser using a beam splitter.

3. The gas concentration detection method according to claim 1, wherein: The adjusting the attenuation state of the second laser beam specifically includes controlling an optical attenuator acting on the second laser beam to adjust the attenuation state of the second laser beam.

4. The gas concentration detection method according to claim 1, wherein: The step of determining the concentration of the target gas based on the gas absorption signal spectrum of the second laser beam after phase adjustment is specifically as follows: receiving a photoelectric detection signal of the second laser beam from a detector, and acquiring a gas absorption signal spectrum line of the second laser beam based on the photoelectric detection signal; Based on the gas absorption signal spectrum, the concentration of the target gas is obtained by inverse derivation.

5. A gas concentration detection device, characterized in that: The gas concentration detection device comprises: an acquisition module, configured to acquire a laser energy value of the first laser beam after attenuation by the target gas to be detected; an adjusting module, configured to adjust the attenuation state of the second laser beam according to the laser energy value, so that the laser energy values ​​of the first laser beam and the second laser beam after attenuation are the same; An adjustment module is used to obtain a photoelectric signal after the attenuation of the first laser beam and the second laser beam after interference, and based on the photoelectric signal, the first laser beam and the second laser beam are phase-adjusted to minimize the value of the photoelectric signal after interference; the adjustment module is also used to control a phase adjustment device acting on the first laser beam and the second laser beam to perform phase adjustment on the first laser beam and the second laser beam; the phase adjustment device is connected to a first optical fiber for transmitting the first laser beam and a second optical fiber for transmitting the second laser beam; the adjustment module is also used to control the phase adjustment device to adjust the optical path of the first optical fiber and the second optical fiber to perform phase adjustment on the first laser beam and the second laser beam; the adjustment module is also used to control a limit adjustment The entire device adjusts the temperature of the first optical fiber and the second optical fiber to change the optical path difference between the first optical fiber and the second optical fiber, wherein the first optical fiber and the second optical fiber control different contact lengths with the temperature adjustment portion to achieve phase adjustment of the first laser beam in the first optical fiber and the second laser beam in the second optical fiber when the temperature of the temperature adjustment portion changes; the contact length of the second optical fiber with the temperature adjustment portion is longer than that of the first optical fiber; when performing phase adjustment, the temperature of the temperature adjustment portion is controlled so that the phase difference between the first laser beam and the second laser beam satisfies the change in the interference fringe ring during detection, until the photoelectric signal value after interference is minimized, and the temperature is set as the optimal temperature for phase adjustment and maintained unchanged; The determination module is used to determine the concentration of the target gas based on the gas absorption signal spectrum line of the second laser beam after phase adjustment.

6. A gas concentration detection system, characterized in that: The system comprises: A gas concentration detection assembly is configured to generate a first laser beam and a second laser beam, emit the first laser beam toward a target gas to be detected, perform phase adjustment and interference detection on the first laser beam and the attenuated second laser beam that have passed through the target gas to be detected, and obtain a gas absorption signal spectrum corresponding to the second laser beam when the photoelectric signal value after interference is minimized. The gas concentration detection assembly includes a phase adjustment device having a temperature adjustment portion, wherein a first optical fiber for transmitting the first laser beam and a second optical fiber for transmitting the second laser beam are fixed to the temperature adjustment portion for phase adjustment of the first laser beam and the second laser beam. The optical path length of the first optical fiber acted upon by the temperature adjustment portion is different from the optical path length of the second optical fiber acted upon by the temperature adjustment portion, and the optical path length difference between the first and second optical fibers is changed when the temperature adjustment portion performs temperature adjustment. A gas concentration detection device, comprising: a memory, a processor, and a gas concentration detection program stored in the memory and executable on the processor, wherein the gas concentration detection program, when executed by the processor, implements the steps of the gas concentration detection method according to any one of claims 1 to 4.

7. The gas concentration detection system according to claim 6, wherein: The gas concentration detection component includes a laser and a beam splitter. The laser is used to emit original laser light, and the beam splitter is used to split the original laser light to obtain a first laser beam and a second laser beam.

8. The gas concentration detection system according to claim 6, wherein: The gas concentration detection component includes an optical attenuator, which is used to attenuate the second laser beam.

9. The gas concentration detection system according to claim 6, wherein: The gas concentration detection component includes a detector, which is used to detect the interference signal between the first laser beam and the second laser beam, and obtain the gas absorption signal spectrum line corresponding to the second laser beam when the photoelectric signal value after interference is minimum.

10. A storage medium, characterized in that: The storage medium stores a gas concentration detection program, which, when executed by a processor, implements the steps of the gas concentration detection method according to any one of claims 1 to 4.

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