The invention discloses a self-calibration method of a TDLAS (
Tunable Diode Laser Absorption Spectroscopy) gas detection
system. The self-calibration method comprises the following steps: according to a calculation formula of a Beer-Lambert principle, inputting first incident
laser, corresponding to the frequency of target gas generated by a gas absorption spectrum, into an
optical path switching device, and absorbing the first incident
laser, entering an appointed standard
gas chamber after passing through the
optical path switching device, by target gas in the appointed standard
gas chamber to obtain first transmission
laser; converting the first transmission laser to obtain a digital
electric signal about the amplitude of the first transmission laser; according to the digital
electric signal, calculating to obtain a
light intensity value I01 of the first incident laser and a
light intensity value It1 of first transmission laser; and based on the two
light intensity values and with introduction of the known gas content C0 in the standard
gas chamber, inverting a calculation coefficient alpha*L1 of target
gas concentration, namely the product of a gas absorption coefficient alpha and standard gas chamber length L1 of the TDLAS gas detection
system. The method can be used for performing self-calibration on the calculation coefficient alpha*L1 of target gas in the
system.