TDLAS-based time-frequency domain combined gas concentration inversion method and device

Abstract

The invention provides a TDLAS-based time-frequency domain combined gas concentration inversion method. The method comprises the following steps that second harmonic signals of standard gas under different concentrations are obtained; second harmonic signal peak values of the standard gas under different concentrations are extracted, and time domain feature points are obtained; second harmonic signals of the standard gas under different concentrations are decomposed, and corresponding frequency spectrums are obtained through fast Fourier transform; second harmonic frequency amplitude components of the standard gas under different concentrations are extracted, and frequency domain feature points are obtained; data of the standard gas under different concentrations are stored and a gas concentration inversion model is established; and the concentration of the gas to be detected is predicted by adopting the gas concentration inversion model. According to the gas concentration inversion method, the time-domain feature points and the frequency-domain feature points of the second harmonic signals containing the gas concentration information are combined to invert the gas concentration, so that the precision of the predicted concentration of the gas to be detected is ensured.

Description

technical field [0001] The invention relates to the technical field of gas concentration detection, in particular to a TDLAS-based time-frequency domain combined gas concentration inversion method and device. Background technique [0002] Tunable semiconductor laser absorption spectroscopy (TDLAS) technology is a spectroscopic measurement method that applies laser light to absorption spectroscopy measurement technology. The principle of using it to detect gas concentration is: the laser passes through the gas to be measured, and the laser wavelength and the gas to be measured When the central wavelengths of the absorption lines are the same, the gas molecules to be measured absorb the laser light of this wavelength, which causes the laser intensity to attenuate. Therefore, the concentration of the gas to be measured is calculated by analyzing the light intensity information of the transmitted light. [0003] However, the light intensity signal received by the current photode...

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Problems solved by technology

[0003] However, in the current photodetector, the light intensity signal received by the transmitted light is extremely weak compared to the background signal and noise, and the influence of the background environment will seriously affect the detection accuracy of the gas concentration.

At the same time, for gas concentration detection and analysis, traditional detection methods only analyze from the perspective of time domain. When the measured gas concentration changes very slightly, the second harmonic Accurate determination, thus affecting the accuracy of gas concentration measurement

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