Low-power control method for laser gas sensors

Abstract

This invention discloses a low-power control method for a laser gas sensor. The laser gas sensor includes a temperature measurement module, a thermoelectric cooler, an environmental parameter detection module, a microprocessor system, and a power supply module. The thermoelectric cooler controls the temperature of the distributed feedback grating inside the laser. The environmental parameter detection module detects environmental parameters around the laser gas sensor. The microprocessor system is signal-connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module, and controls their operating modes. The power supply module provides electrical energy and includes two circuit output terminals: one connected to the microprocessor system, and the other connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module. This invention offers the advantages of high detection accuracy and reduced overall power consumption.

Description

Technical Field

[0001] This invention belongs to the field of laser gas detection technology, specifically relating to a low-power control method for a laser gas sensor. Background Technology

[0002] Laser gas detection technology is one of the core applications of tunable diode laser absorption spectroscopy (TDLAS), achieving high-precision detection by measuring the absorption intensity of gas molecules to a specific wavelength of laser light. TDLAS technology, with its high sensitivity, fast response, and anti-interference capabilities, has driven the widespread application of laser gas detection in fields such as industrial safety, environmental monitoring, medical diagnosis, and scientific research. Among these, distributed feedback (DFB) lasers, due to their narrow linewidth and tunable wavelength characteristics, have become ideal light sources for detecting gases such as methane and carbon dioxide.

[0003] However, DFB laser-based gas sensing systems still face a power consumption bottleneck in industrial applications. In special environments such as coal mines and chemical plants, high power consumption reduces the carrying distance and poses risks of power overload or overheating. Simultaneously, temperature control energy consumption surges under extreme temperature conditions, easily triggering intrinsically safe power supply protection. In portable, wireless, or remote monitoring applications, sensors rely on battery power, and high power consumption significantly shortens battery life and increases maintenance costs. To reduce power consumption and improve battery life, a low-power control method for laser gas sensors is proposed. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] Therefore, this invention proposes a low-power control method for laser gas sensors, which has the advantages of high detection accuracy and reduced overall power consumption.

[0006] A low-power control method for a laser gas sensor according to an embodiment of the present invention includes: a laser gas sensor, the laser gas sensor comprising: a temperature measurement module, a thermoelectric cooler, an environmental parameter detection module, a microprocessor system, and a power supply module; the temperature measurement module is used to detect the temperature of a distributed feedback grating inside the laser; the thermoelectric cooler is used to control the temperature of the distributed feedback grating inside the laser; the environmental parameter detection module is used to detect environmental parameters around the laser gas sensor; the microprocessor system is signal-connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module, and is used to control the operating mode of the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module; the power supply module is used to provide electrical energy, and includes two circuit output terminals, one of which is connected to the microprocessor system, and the other of which is connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module;

[0007] The low-power control method includes the following steps:

[0008] S1. Preset the temperature value required for the operation of the distributed feedback grating;

[0009] S2. Before the laser gas sensor is started, the temperature of the distributed feedback grating is detected by the temperature measurement module, and the distributed feedback grating is adjusted to the preset temperature value by the thermoelectric cooler.

[0010] S3. When the temperature of the distributed feedback grating reaches a certain value, the laser driver and PD detection module are started, and the working time of the distributed feedback grating at the required temperature value is predicted by the thermal inertia of the distributed feedback grating itself. Based on this time, the temperature measurement module and thermoelectric cooler are turned off.

[0011] S4. After the specified time has elapsed, the temperature measurement module and thermoelectric cooler will resume operation. At this time, the laser driver and PD detection module will start in continuous operation; or the laser driver and PD detection module will be turned off, and then the acquisition signal processing and concentration calculation will be performed to end the operation.

[0012] According to one embodiment of the present invention, in S2, the real-time temperature of the distributed feedback grating, the preset temperature value required for the operation of the distributed feedback grating, and the change in ambient temperature are detected by the temperature measurement module. Combining the flexibility of fuzzy logic and PID control algorithm, the heating or cooling power of the thermoelectric cooler is dynamically adjusted according to the change in ambient temperature and the dynamic characteristics of the system, so as to achieve precise control of the temperature of the distributed feedback grating inside the laser.

[0013] According to one embodiment of the present invention, the specific steps for dynamically adjusting the heating or cooling power of a thermoelectric cooler are as follows:

[0014] S21. Based on the real-time detected temperature T of the distributed feedback grating inside the laser. actual and the preset temperature value T required for the operation of the distributed feedback grating set contrast,

[0015] Calculate the temperature error e(t) = T set -T actual (This reflects the degree to which the current temperature deviates from the target).

[0016] Calculate the rate of change of temperature error: Δe(t)=e(t)-e(t-1), which reflects the trend of temperature error change (heating / cooling rate, fluctuation amplitude);

[0017] S22. Traditional PID control output for thermoelectric coolers

[0018]

[0019] S23. Adjust the proportional gain K of the PID controller based on the temperature error and the rate of change of the temperature error. p Integral K i and differential K d Parameter; K p (Proportional Term): Quickly responds to the current error and adjusts rapidly when the error is large; K i (Integral term): Accumulate historical errors to eliminate "static error" (long-term temperature deviation); K d (Differential term): Predicts the trend of error changes and suppresses overshoot and oscillation;

[0020] S24. Establish a fuzzy rule base. Input variables: Convert the error e(t) and the rate of change of error Δe(t) into fuzzy sets, {B, M, S, Z} corresponding to {large, medium, small, zero} respectively, converting precise numerical values ​​into fuzzy language to facilitate rule matching; Output variable: Proportion K p Integral K i and differential K d The parameters also correspond to fuzzy sets, with {B, M, S, Z} corresponding to {large, medium, small, zero} respectively;

[0021] S25. Optimize the rules based on a large amount of experimental data in the early stage, and establish the rule of adjusting the input fuzzy quantity → output parameter;

[0022] When the error e(t) is large: increase the ratio K p To accelerate the response and reduce the integral K i To avoid integral K i saturation;

[0023] When the error e(t) is small: increase the integral K i Eliminate steady-state error and adjust the differential K. d Suppress high-frequency oscillations;

[0024] When the error e(t) changes rapidly, increase the differential K. d Suppress overshoot;

[0025] S26. Convert the fuzzy output into precise parameters using the maximum membership method, and update the PID parameters:

[0026] K p =K p0 +ΔK p

[0027] K i =K i0 +ΔK i

[0028] K d =K d0 +ΔK d ;

[0029] Where K p0 K i0 K d0 These are the initial PID parameters, set based on prior debugging / experimentation; ΔK p ΔK i ΔK d It is the output of the fuzzy controller.

[0030] According to one embodiment of the present invention, in S3, the operating time of the distributed feedback grating at the required temperature value is predicted by a thermal inertia combined with intelligent predictive control method. The distributed feedback grating is kept warm by utilizing the heat generated by the operation of the thermoelectric cooler and the hysteresis of temperature changes due to the thermal capacity and thermal resistance of the distributed feedback grating itself. According to the prediction results, the operation of the thermoelectric cooler is stopped when the temperature of the distributed feedback grating is within the allowable fluctuation range, and the thermoelectric cooler is turned on when the temperature of the distributed feedback grating exceeds the allowable fluctuation range.

[0031] According to one embodiment of the present invention, in S3, T(t) = T0 + ΔT*(1-e -t / τ The temperature change pattern is calculated, where T(t) is the temperature at time t; T0 is the initial temperature or the set temperature reference; ΔT is the maximum temperature fluctuation less than 0.3℃; and τ is the thermal time constant, which is determined by the thermal capacity and thermal resistance of the laser package. It takes about 1 to 2 seconds to reflect the "speed" of temperature change. The larger τ is, the slower the temperature change and the stronger the thermal inertia.

[0032] According to one embodiment of the present invention, the PD detection module is used to collect signals and calculate gas concentration. The PD detection module discretizes the analog signal through an ADC, converting the continuously changing analog signal into a discrete digital signal (a sequence of 0s and 1s that a computer can recognize). The sampled signal is filtered and denoised, and the signal amplitude is dynamically analyzed to determine whether it exceeds a preset threshold. If the signal is too weak or too strong, the adaptive gain control algorithm dynamically adjusts the amplifier gain to ensure that the signal is always in the optimal quantization range. The feedback loop sends the adjusted signal back into the sampling chain to form a closed-loop control.

[0033] According to one embodiment of the present invention, an environmental parameter detection module is further included. The environmental parameter detection module is used to detect the surrounding environmental parameters of the laser gas sensor. If the ambient temperature of the laser gas sensor changes significantly, the temperature measurement module is activated to monitor the temperature of the distributed feedback grating, so as to avoid the temperature value of the distributed feedback grating exceeding the required temperature value of the distributed feedback grating due to the change in the ambient temperature of the laser gas sensor.

[0034] According to one embodiment of the present invention, during the detection process, if the detection data fluctuates significantly, the environmental parameter detection module transmits the detection data to the microprocessor system; if the detection data fluctuates only slightly, the detection data within that time period is packaged and uploaded after a certain period of time.

[0035] According to one embodiment of the present invention, the power supply module includes a DC-DC voltage converter, a first LDO voltage converter, and a second LDO voltage converter; the DC-DC voltage converter is connected to an external power supply and converts the power supply voltage to DC 3.3V to power the downstream; the first LDO voltage converter and the second LDO voltage converter convert DC 3.3V to 3.0V; the microprocessor system is connected to the first LDO voltage; and the temperature measuring module and the thermoelectric cooler are both connected to the second LDO voltage converter.

[0036] The beneficial effects of this invention are as follows: Before the laser gas sensor begins detection, the distributed feedback grating is pre-temperature regulated, avoiding wavelength drift caused by large temperature fluctuations in the grating and ensuring the accuracy of the detection data. Furthermore, because the laser gas sensor's detection operation is not simultaneously activated with the thermoelectric cooler, detection only begins when the grating temperature is stable, ensuring current stability and preventing large temperature fluctuations in the grating due to changes in the driving current, further guaranteeing the accuracy of the detection data. Additionally, due to the stable wavelength, the detection data is more accurate, eliminating the need for an environmental parameter detection module to detect the outside of the laser gas sensor. This avoids the need for calculation and compensation of detection data based on environmental data, as is present in existing technologies, thus reducing the overall system power consumption.

[0037] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0040] Figure 1 This is a schematic diagram of the cycle workflow of the present invention;

[0041] Figure 2 This is a schematic diagram of the power supply and control of the present invention;

[0042] Figure 3This is a schematic diagram of the PD detection module of the present invention;

[0043] Figure 4 This is a schematic diagram of current testing when the laser gas sensor is activated simultaneously; at this time, the inrush current is obvious.

[0044] Figure 5 This is a schematic diagram of the current test structure after adjusting the start-up step of the present invention, at which point there is no inrush current;

[0045] Figure 6 This is a bar chart illustrating the test error of the present invention under different temperature conditions;

[0046] Figure 7 This is a schematic diagram of the test error data of the present invention under different temperature environments; Detailed Implementation

[0047] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] The low-power control method of a laser gas sensor according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] like Figure 1-7 As shown, a low-power control method for a laser gas sensor according to an embodiment of the present invention includes a laser gas sensor, which comprises: a temperature measurement module, a thermoelectric cooler, an environmental parameter detection module, a microprocessor system, and a power supply module; the temperature measurement module is used to detect the temperature of a distributed feedback grating inside the laser; the thermoelectric cooler is used to control the temperature of the distributed feedback grating inside the laser; the environmental parameter detection module is used to detect the surrounding environmental parameters of the laser gas sensor; the microprocessor system is signal-connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module, and is used to control the operating mode of the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module; the power supply module is used to provide electrical energy and includes two circuit output terminals, one circuit output terminal connected to the microprocessor system, and the other circuit output terminal connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module;

[0052] The low-power control method includes the following steps:

[0053] S1. Preset the temperature value required for the operation of the distributed feedback grating. This temperature value can be a range.

[0054] S2. Before the laser gas sensor is started, the temperature of the distributed feedback grating is detected by the temperature measurement module, and the distributed feedback grating is adjusted to the preset temperature value by the thermoelectric cooler.

[0055] S3. When the temperature of the distributed feedback grating reaches a certain value, the working time required for the temperature value of the distributed feedback grating is predicted by the thermal inertia of the distributed feedback grating itself, and the temperature measurement module and thermoelectric cooler are turned off according to the time. At this time, the laser driver and PD detection module are started.

[0056] S4. After the specified time has elapsed, the temperature measurement module and thermoelectric cooler will resume operation. At this time, the laser driver and PD detection module will start in continuous operation; or the laser driver and PD detection module will be turned off, and then the acquisition signal processing and concentration calculation will be performed to end the operation.

[0057] In this embodiment, by first adjusting the temperature of the distributed feedback grating, the laser gas sensor is in its optimal operating state from the initial operation. Since the gas to be measured only has an absorption peak at a specific wavelength, the emission wavelength of the laser must be precisely matched to ensure detection accuracy. Therefore, the wavelength drift caused by large temperature fluctuations of the distributed feedback grating is avoided, ensuring the accuracy of the detection data. Furthermore, since the laser gas sensor's detection operation is not started simultaneously with the thermoelectric cooler, and the laser gas sensor only starts detection when the temperature of the distributed feedback grating is stable, the stability of the current is ensured, avoiding large temperature fluctuations of the distributed feedback grating caused by changes in the driving current, further ensuring the accuracy of the detection data. In addition, since the wavelength is stable during this process, the detection data is relatively accurate. At this time, there is no need for the environmental parameter detection module to detect the outside of the laser gas sensor, thus avoiding the phenomenon of calculating and compensating for the detection data through environmental data in the prior art, thereby reducing the power consumption of the entire laser gas sensor.

[0058] In S2, the temperature of the distributed feedback grating is detected by the temperature measurement module, along with the preset temperature value required for the distributed feedback grating to operate and the change in ambient temperature. Combining the flexibility of fuzzy logic and the PID control algorithm, the heating or cooling power of the thermoelectric cooler is dynamically adjusted according to changes in ambient temperature and the dynamic characteristics of the system, so as to achieve precise control of the temperature of the distributed feedback grating inside the laser.

[0059] Specifically, the steps for dynamically adjusting the heating or cooling power of a thermoelectric cooler are as follows:

[0060] S21. Based on the real-time detected temperature T of the distributed feedback grating inside the laser. actual and the preset temperature value T required for the operation of the distributed feedback grating set contrast,

[0061] Calculate the temperature error e(t) = T set -T actual This reflects the degree to which the current temperature deviates from the target.

[0062] Calculate the rate of change of temperature error: Δe(t)=e(t)-e(t-1); This reflects the trend of temperature error change (heating / cooling rate, fluctuation amplitude);

[0063] S22. Traditional PID control output for thermoelectric coolers

[0064]

[0065] S23. Adjust the proportional gain K of the PID controller based on the temperature error and the rate of change of the temperature error. p Integral K i and differential Kd parameter;

[0066] K p (Proportional term): Quickly responds to the current error and adjusts rapidly when the error is large;

[0067] K i (Integral term): Accumulate historical errors to eliminate "static error" (long-term temperature deviation);

[0068] K d (Differential term): Predicts the trend of error changes and suppresses overshoot and oscillation;

[0069] S24. Establish a fuzzy rule base. Input variables: Convert the error e(t) and the rate of change of error Δe(t) into fuzzy sets, {B, M, S, Z} corresponding to {large, medium, small, zero} respectively (convert precise numerical values ​​into fuzzy language to facilitate rule matching); Output variable: Proportion K p Integral K i and differential K d The parameters also correspond to fuzzy sets, with {B, M, S, Z} corresponding to {large, medium, small, zero} respectively;

[0070] S25. (Optimize rules based on extensive experimental data from the early stages) Establish rules for adjusting input fuzzy quantities and output parameters;

[0071] When the error e(t) is large: increase the ratio K p To accelerate the response and reduce the integral K i To avoid integral K i Saturation (overshoot caused by excessively rapid integral accumulation);

[0072] When the error w(t) is small: increase the integral K i Eliminate steady-state error and adjust the differential K. d Suppress high-frequency oscillations;

[0073] When the error e(t) changes rapidly (Δe(t) is large), increase the differential K. d Suppress overshoot;

[0074] S26. Convert the fuzzy output into precise parameters using the maximum membership method, and update the PID parameters:

[0075] K p =K p0 +ΔK p

[0076] K i =K i0 +ΔK i

[0077] K d =K d0+ΔK d ;where K p0 K i0 K d0 These are the initial PID parameters, set based on prior debugging / experimentation; ΔK p ΔK i ΔK d It is the output of the fuzzy controller.

[0078] In this embodiment, by combining the flexibility of fuzzy logic and the precision of PID control with the changes in ambient temperature, the real-time temperature of the laser, and the set temperature, it can effectively cope with changes in ambient temperature and the dynamic characteristics of the system, dynamically adjust the heating or cooling power of the thermoelectric cooler, so as to achieve precise control of the laser temperature, ensure that the emission wavelength of the laser is precisely matched with the absorption peak of the gas to be measured, so as to achieve high accuracy of detection data and reduce the energy consumption of the thermoelectric cooler.

[0079] In S3, the operating time of the distributed feedback grating is predicted by a combination of thermal inertia and intelligent predictive control. The heat generated by the thermoelectric cooler and the lag of temperature change due to the thermal capacity and thermal resistance of the distributed feedback grating itself are used to keep the distributed feedback grating warm. According to the prediction results, the operation of the thermoelectric cooler is stopped when the temperature of the distributed feedback grating is within the allowable fluctuation range, and the thermoelectric cooler is turned on when the temperature of the distributed feedback grating exceeds the allowable fluctuation range.

[0080] Specifically, we use T(t) = T0 + ΔT*(1-e -t / τ The temperature change pattern is calculated, where T(t) is the temperature at time t; T0 is the initial temperature (or the set temperature reference); ΔT is the maximum temperature fluctuation (less than 0.3℃); and τ is the thermal time constant, which is determined by the thermal capacity and thermal resistance of the laser package (about 1 to 2 seconds, reflecting the "speed" of temperature change; the larger the τ, the slower the temperature change and the stronger the thermal inertia).

[0081] In this embodiment, the laser's own heat dissipation system (thermoelectric cooler, heat sink) and distributed feedback grating have thermal capacity (the ability to store heat) and thermal resistance (the characteristic that hinders heat transfer). Temperature changes exhibit lag. When the temperature reaches the set value, the thermoelectric cooler is turned off. The laser will not immediately and drastically heat up or cool down, but will change slowly due to thermal inertia. Based on this characteristic of slow temperature change caused by thermal inertia, an algorithm predicts the temperature fluctuation range and determines whether the temperature will exceed the allowable fluctuation range before the next temperature control cycle (before the thermoelectric cooler is restarted). If the predicted temperature will not exceed the limit, the thermoelectric cooler remains off, maintaining an approximately constant temperature through thermal inertia. If it is likely to exceed the limit, the thermoelectric cooler is triggered to control the temperature, achieving periodic low-power operation. Specifically, in gas detection scenarios, the wavelength of the DFB laser is affected by temperature (wavelength temperature coefficient approximately 0.1 nm / ℃). To achieve the required detection accuracy, the wavelength drift must be less than 0.03 nm; converted to temperature fluctuation, this must be less than 0.3℃ (because 0.1 nm / ℃ × 0.3℃ = 0.03 nm). When the thermoelectric cooler is turned off, the temperature change is very small (℃) within a time interval τ / 2 (for example, τ = 2 seconds, which is within 1 second), meeting the requirement of "approximate constant temperature". In other words, utilizing thermal inertia, the temperature fluctuation will not exceed 0.3℃ within a short period (τ / 2) after the thermoelectric cooler is turned off, which just meets the detection accuracy requirement. During this period, the thermoelectric cooler can be turned off to save power. At the end of the cycle, it is determined whether to restart the thermoelectric cooler, and this cycle is repeated to achieve "low power constant temperature".

[0082] The PD detection module is used to acquire signals and calculate gas concentration. The PD detection module discretizes the analog signal through ADC (converting the continuously changing analog signal into a discrete digital signal (a sequence of 0s and 1s that the computer can recognize)) and filters and denoises the sampled signal. It dynamically analyzes the signal amplitude to determine whether it exceeds the preset threshold. If the signal is too weak or too strong, the adaptive gain control algorithm dynamically adjusts the amplifier gain to ensure that the signal is always in the optimal quantization range. The feedback loop sends the adjusted signal back into the sampling chain to form a closed-loop control.

[0083] Specifically, such as Figure 3 As shown, the photodetector first converts the change in light intensity after absorption by the gas into a weak current signal. This current signal then enters a transimpedance amplifier, where it is converted into a voltage signal by a feedback resistor and initially amplified to increase signal strength for subsequent processing. Next, a filtering circuit filters the amplified signal, removing noise and interference components to make the signal smoother and more stable. Finally, the signal enters an adaptive amplifier circuit, where a digital potentiometer automatically adjusts the gain to achieve adaptive range switching, ensuring linear amplification within a suitable range and avoiding saturation or insufficient resolution. The processed signal is then sent to an analog-to-digital converter (ADC) for sampling, completing the entire conversion process from optical signal to digital signal.

[0084] In the PD detection module, signal sampling and adaptive gain adjustment are crucial steps. The analog signal is discretized using an ADC, and its sampling rate must satisfy the Nyquist theorem to avoid aliasing (signal distortion, such as a rapidly changing signal being incorrectly sampled as a slowly changing one). The sampled signal is filtered and denoised, and the signal amplitude is dynamically analyzed to determine if it exceeds a preset threshold. If the signal is too weak or too strong, the adaptive gain control algorithm dynamically adjusts the amplifier gain to ensure the signal is always within the optimal quantization range. The feedback loop re-feeds the adjusted signal into the sampling chain, forming a closed-loop control of detection, adjustment, and re-detection. This effectively solves the problem of distortion or decreased quantization accuracy caused by sudden changes in signal amplitude, such as sudden changes in gas concentration or light intensity. The gain adapts quickly, providing a reliable basis for subsequent data processing and decision-making. Adaptive gain closed-loop control solves the problem of signal distortion caused by sudden changes.

[0085] The environmental parameter detection module is used to detect the surrounding environmental parameters of the laser gas sensor. If the ambient temperature of the laser gas sensor changes significantly, the temperature measurement module is activated to monitor the temperature of the distributed feedback grating, so as to prevent the temperature value of the distributed feedback grating from exceeding the required temperature value due to changes in the ambient temperature of the laser gas sensor.

[0086] In laser gas sensors, the Beer-Lambert law is used, which states that the degree of absorption of a gas by a specific wavelength of laser light is positively correlated with its concentration. A quantitative relationship model between gas absorption spectra and concentration is established using calibration data. The direct absorption method is employed to fit and invert the absorption peaks, thereby accurately calculating the gas concentration and converting changes in the optical signal into numerical concentration values. To address environmental interference factors, such as high temperatures, rapid gas molecule movement, and altered absorption characteristics, a temperature-pressure compensation module is designed. Based on the detection data from the environmental parameter detection module, the variation law of the gas absorption coefficient under different temperature and pressure conditions is experimentally calibrated, and compensation parameters are established. In actual measurements, for non-calibrated operating points, a piecewise linear interpolation algorithm is used for dynamic compensation, effectively correcting the influence of environmental changes on the measurement results. This ensures that the sensor can accurately and stably output gas concentration data even under complex environmental conditions, using temperature and pressure compensation to offset environmental interference.

[0087] During the environmental parameter detection process, if the detected data fluctuates significantly, the data is transmitted to the microprocessor system. The microprocessor system then uses this data to calculate the activation timing of the temperature measurement module or the temperature-pressure compensation module. If the detected data fluctuates only slightly, the data within that time frame is packaged and uploaded after a certain interval. By optimizing the communication protocol and adopting batch data transmission, discrete periodic monitoring data is packaged into groups for transmission, significantly reducing the number of wake-up calls to the communication module and the energy consumption per transmission. Intelligent data filtering uses threshold judgment and change detection to filter redundant data, uploading only valid fluctuation information and avoiding unnecessary power consumption caused by repeated transmissions. Protocol stack optimization simplifies the communication handshake process and data packet header structure, shortening transmission time and reducing additional energy consumption caused by protocol overhead. This reduces unnecessary energy consumption while ensuring real-time data upload.

[0088] The power supply module includes a front-end DC-DC voltage converter using a high-efficiency, low-ripple chip, maintaining high conversion efficiency over a wide input voltage range. This converter transforms the external input power into DC 3.3V for downstream power supply. The DC-DC voltage converter connects to an external power source, which can be a battery. The back-end uses a first and second LDO voltage converter with high-precision chips to convert DC 3.3V to 3.0V. For ease of control, the first LDO voltage converter connects to the microprocessor system, and the second LDO voltage converter connects to peripheral circuits such as the PD detection module, laser driver, output module, laser temperature control (temperature measurement module, thermoelectric cooler), environmental parameter detection module, heat dissipation system, and temperature-pressure compensation module. Based on the actual application and the laser's operating characteristics, the system features a modular, controllable power supply design. The microprocessor manages the power supply to the laser driver, temperature control, detection module, and output module, implementing a periodic operating mode.

[0089] like Figure 4-5 As shown, by precisely controlling the delayed start-up strategy of the temperature control system through software, the transient high current generated when multiple modules are powered on simultaneously is successfully suppressed, significantly improving system stability. By controlling the start-up sequence and utilizing waste heat to calculate the laser temperature control start-up and shutdown cycle, both current surges during the start-up phase and steady-state power consumption during operation can be suppressed. Simultaneously, the optimized communication protocol reduces redundant communication overhead while ensuring system performance, achieving a significant reduction in overall power consumption and providing a highly efficient energy-saving solution for the terminal. Furthermore, by optimizing voltage conversion, using 18V power supply, the first-stage DC-DC voltage converter converts 18V to 3.3V, and the second-stage first LDO voltage converter and second LDO voltage converter convert 3.3V to 3.0V to power the terminal. Compared to the traditional first-stage 5V output power supply, this method reduces power consumption by 70%. Figure 6-7As shown, the above optimizations ensure that the detection accuracy of the laser gas sensor is almost unaffected by extreme temperature differences of -10℃ or 50℃.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A low-power control method for a laser gas sensor, characterized in that, Includes a laser gas sensor, the laser gas sensor comprising: Temperature measurement module, which is used to detect the temperature of the distributed feedback grating inside the laser; A thermoelectric cooler for controlling the temperature of a distributed feedback grating inside a laser; The microprocessor system is connected to the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module via signal connection, and is used to control the working mode of the temperature measurement module, the thermoelectric cooler, and the environmental parameter detection module. Power supply module, the power supply module is used to provide electrical energy; The low-power control method includes the following steps: S1. Preset the temperature value required for the operation of the distributed feedback grating; S2. Before the laser gas sensor is started, the temperature of the distributed feedback grating is detected by the temperature measurement module, and the distributed feedback grating is adjusted to the preset temperature value by the thermoelectric cooler. S3. When the temperature of the distributed feedback grating reaches a certain value, the laser driver and PD detection module are started, and the working time of the distributed feedback grating at the required temperature value is predicted by the thermal inertia of the distributed feedback grating itself. Based on this time, the temperature measurement module and thermoelectric cooler are turned off. S4. After the specified time has elapsed, the temperature measurement module and thermoelectric cooler will resume operation. At this time, the laser driver and PD detection module will start in continuous operation; or the laser driver and PD detection module will be turned off, and then the acquisition signal processing and concentration calculation will be performed to end the operation.

2. The low-power control method for the laser gas sensor according to claim 1, characterized in that, In S2, the temperature of the distributed feedback grating is detected by the temperature measurement module, along with the preset temperature value required for the distributed feedback grating to operate and the change in ambient temperature. Combining the flexibility of fuzzy logic and the PID control algorithm, the heating or cooling power of the thermoelectric cooler is dynamically adjusted according to changes in ambient temperature and the dynamic characteristics of the system, so as to achieve precise control of the temperature of the distributed feedback grating inside the laser.

3. The low-power control method for the laser gas sensor according to claim 2, characterized in that, The specific steps for dynamically adjusting the heating or cooling power of a thermoelectric cooler are as follows: S21. Based on the real-time detected temperature of the distributed feedback grating inside the laser. and the temperature value required for the operation of the preset distributed feedback grating contrast, Calculate temperature error ; Calculate the rate of change of temperature error: Where t represents time; S22. Traditional PID control output for thermoelectric coolers ； S23. Adjust the proportional gain of the PID controller based on the temperature error and the rate of change of the temperature error. ,integral and differential parameter; S24. Establish a fuzzy rule base, input variables: including error... and error change rate Transform into fuzzy sets, where {B, M, S, Z} correspond to {large, medium, small, and zero} respectively; Output variable: Proportion ,integral and differential The parameters also correspond to fuzzy sets, with {B, M, S, Z} corresponding to {large, medium, small, and zero} respectively; S25. Establish rules for adjusting output parameters based on input fuzzy values; S26. Convert the fuzzy output into precise parameters using the maximum membership method, and update the PID parameters.

4. The low-power control method for the laser gas sensor according to claim 3, characterized in that, The rule for adjusting the output parameters by inputting the fuzzy quantity in S25 is as follows: error Large: Increase the proportion Accelerate response and reduce integral. To avoid points saturation; error Hour: Increase points Eliminate steady-state error and adjust the derivative. Suppress high-frequency oscillations; When error When the change is rapid, increase the derivative. Suppress overshoot.

5. The low-power control method for the laser gas sensor according to claim 4, characterized in that, The method for updating PID parameters in S26 is as follows: ； ； ； in , , These are the initial PID parameters; , , It is the output of the fuzzy controller.

6. The low-power control method for the laser gas sensor according to claim 5, characterized in that, In S3, the operating time of the distributed feedback grating is predicted by a combination of thermal inertia and intelligent predictive control. The heat generated by the thermoelectric cooler and the lag of temperature change due to the thermal capacity and thermal resistance of the distributed feedback grating itself are used to keep the distributed feedback grating warm. According to the prediction results, the operation of the thermoelectric cooler is stopped when the temperature of the distributed feedback grating is within the allowable fluctuation range, and the thermoelectric cooler is turned on when the temperature of the distributed feedback grating exceeds the allowable fluctuation range.

7. The low-power control method for the laser gas sensor according to claim 6, characterized in that, In S3, the following is adopted: Calculate the temperature change pattern, where It is the temperature at time t; It is the initial temperature; It is the maximum temperature fluctuation. The thermal time constant is determined by the thermal capacity and thermal resistance of the laser package.

8. The low-power control method for the laser gas sensor according to claim 7, characterized in that, The PD detection module is used to collect signals and calculate gas concentration. The PD detection module discretizes the analog signal through ADC, filters and denoises the sampled signal, dynamically analyzes the signal amplitude, and determines whether it exceeds the preset threshold. If the signal amplitude exceeds the preset threshold, the adaptive gain control algorithm dynamically adjusts the amplifier gain to ensure that the signal is always in the optimal quantization range. The feedback loop then sends the adjusted signal back into the sampling chain, forming a closed-loop control.

9. The low-power control method for the laser gas sensor according to claim 1, characterized in that, It also includes an environmental parameter detection module, which is used to detect the surrounding environmental parameters of the laser gas sensor. If the change in the ambient temperature of the laser gas sensor exceeds a preset temperature threshold, the temperature measurement module is activated to monitor the temperature of the distributed feedback grating, so as to avoid the temperature value of the distributed feedback grating from exceeding the required temperature value of the distributed feedback grating due to the change in the ambient temperature of the laser gas sensor.

10. The low-power control method for the laser gas sensor according to claim 9, characterized in that, During the detection process, if the change in the detection data exceeds a preset fluctuation threshold, the environmental parameter detection module will transmit the detection data to the microprocessor system. If the detection data fluctuates slightly, the detection data within that time period will be packaged and uploaded after a certain period of time.

11. The low-power control method for the laser gas sensor according to claim 1, characterized in that, The power supply module includes a DC-DC voltage converter, a first LDO voltage converter, and a second LDO voltage converter; The DC-DC voltage converter connects to an external power source and converts the power supply voltage to DC 3.3V to power the next stage. The first LDO voltage converter and the second LDO voltage converter convert DC 3.3V to 3.0V. The microprocessor system is connected to the first LDO voltage, and the temperature measurement module and thermoelectric cooler are both connected to the second LDO voltage converter.

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