The invention relates to the technical field of
hydrogen concentration detection, and particularly discloses a TDLAS (
tunable diode laser absorption spectroscopy) absorption spectrum-based trace
hydrogen concentration
sensing system, which is used for solving the problems of low detection sensitivity, narrow
linear range, large
system drift and dependence on external calibration in TDLAS
hydrogen detection, and comprises a
laser emission module and a photoelectric detection module, the
laser emission module and the photoelectric detection module are connected through the dual-optical-path absorption module, the photoelectric detection module is connected with a
harmonic extraction module, the
harmonic extraction module is connected with a normalization
processing module, and the normalization
processing module is connected with a concentration inversion module; according to the device and the method, a symmetrical double-light-path structure is constructed, a
harmonic signal normalization and differential
compensation algorithm is adopted, and a high-pressure reference gas
pool and a segmented fitting model are combined, so that high-
linearity, high-sensitivity and calibration-free concentration detection of hydrogen within 0.01-100% is realized, and the hydrogen trace recognition capability is improved.