Research On Optical Path Correction System Based On TDLAS Technology

With the progress of the tunable semiconductor laser manufacturing technology,based on a Tunable semiconductor Laser Absorption Spectroscopy technology of gas concentration measurement theory is gradually transition from laboratory research to industrial application.At present,it has been applied in the fields of energy and electricity,combustion process diagnosis,atmospheric trace gas monitoring and ecological measurement.But caused by the volatility of the nature,the random variation of atmosphere temperature and pressure,effect factors,such as equipment accuracy,light path in the process of transmission shift will happen and affect the gas concentration measurement result,in order to eliminate the effects,this paper studies the TDLAS technology,design the gas concentration measurement device based on the TDLAS technology,and put forward to solve the problem of light path deviation innovative optical path correction module.Through the HITRAN database query different gas absorption spectral line shape,determine the CO2 gas absorption spectrum wavelength is 1572.3351nm,design consists of laser transmitting unit,absorbing pond cell,light path correction unit,signal receiving and data processing unit four parts of gas concentration measurement system,choose experimental equipment complete the construction of the test bench.Focus on the design of the optical path correction module,the completion of the main control board circuit design and later software debugging,reliable completion of the sensor signal acquisition,stepping motor control and control algorithm.Comparing the key steps of direct absorption method and modulation technique in data processing,wavelength modulation method was selected to process the experimental data.In order to obtain better data,the parameters of the phase-locked amplifier were optimized and set during the experiment,and the experiment was carried out to obtain the experimental data and calculate the experimental results.The analysis of the experimental results shows that the gas concentration measurement device based on TDLAS technology in this paper has high accuracy and good stability.The designed optical path correction unit can improve the measuring accuracy of the whole device and maintain the stability of the device.