發(fā)布時(shí)間：2018-03-18 10:06

  本文選題：量子級(jí)聯(lián)激光器　切入點(diǎn)：鎖相放大器　出處：《吉林大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：在開采難度大的地區(qū)進(jìn)行礦井開采作業(yè)極易造成煤氣層泄漏和煤塵自燃等重大安全事故。因此研制出可實(shí)時(shí)監(jiān)控礦井下CO氣體濃度的傳感器具有重大的安全意義。目前礦用氣體檢測(cè)儀主要的研究發(fā)展方向是應(yīng)用紅外光譜吸收技術(shù)對(duì)有毒氣體進(jìn)行識(shí)別與濃度測(cè)量。其中選用單色性好、準(zhǔn)直度的量子級(jí)聯(lián)激光器(QCL)作為紅外檢測(cè)系統(tǒng)的光源與其他紅外光譜吸收技術(shù)相比,具有更強(qiáng)的分子鑒別力和更高的檢測(cè)精度。因此本課題具有十分重要的研究意義�；�于脈沖式中紅外QCL的氣體檢測(cè)系統(tǒng)中主要存在兩大關(guān)鍵問題:一、應(yīng)用脈沖鎖相放大技術(shù)精準(zhǔn)提取窄脈沖傳感信號(hào);二、有效調(diào)控氣體吸收池溫度、壓強(qiáng)等參數(shù),實(shí)現(xiàn)最佳檢測(cè)過程。本論文研究基于以上關(guān)鍵問題展開。首先設(shè)計(jì)并實(shí)現(xiàn)一種窄脈沖鎖相放大器,主要由窄帶濾波電路、乘法器電路、低通濾波電路等構(gòu)成。并對(duì)其開展了詳細(xì)的功能驗(yàn)證實(shí)驗(yàn),實(shí)驗(yàn)結(jié)果表明該窄脈沖鎖相放大器具有良好的頻率響應(yīng)(中心頻率5k Hz)、較低的通頻帶寬度(帶寬80Hz)、較高的線性度(擬合優(yōu)度98.043%)。其次對(duì)紅外吸收池的多種參數(shù)進(jìn)行控制,包括溫度控制單元和流量控制單元兩部分。利用Fuzzy-PID復(fù)合控制理論對(duì)不銹鋼密閉腔體開展溫度控制實(shí)驗(yàn),實(shí)驗(yàn)曲線表明該溫控系統(tǒng)具有較快的響應(yīng)速度(響應(yīng)時(shí)間7mins)及較低的穩(wěn)態(tài)誤差(控制精度±0.2℃)。并利用質(zhì)量流量計(jì)對(duì)模擬氣室的流量進(jìn)行調(diào)控,多次控制結(jié)果證明,該流量控制單元可實(shí)現(xiàn)誤差在滿程的5%左右的控制功能,且具有良好的重復(fù)性。最后通過實(shí)驗(yàn)室完整的CO檢測(cè)平臺(tái)進(jìn)行了CO氣體標(biāo)定實(shí)驗(yàn),測(cè)試結(jié)果證實(shí)了在紅外吸收池溫度、流量等參數(shù)選定時(shí),所研制的鎖相放大器可以有效地檢測(cè)出紅外吸收池通入的CO氣體濃度,且系統(tǒng)檢測(cè)精度較高、穩(wěn)定性較好。
[Abstract]:It is easy to cause gas leakage and coal dust spontaneous combustion and other major safety accidents in mining operation in areas where mining is difficult. Therefore, it is of great safety significance to develop a sensor that can monitor CO concentration under mine in real time. At present, the main research direction of mine gas detector is to use infrared spectrum absorption technology to identify and measure the concentration of toxic gas. As the light source of infrared detection system, the collimated quantum cascade laser (QCL) is compared with other infrared absorption techniques. Therefore, this subject has very important research significance. There are two key problems in the gas detection system based on pulse mid-infrared QCL: first, The pulse phase-locked amplification technique is used to accurately extract the narrow pulse sensing signal. Second, the parameters such as temperature and pressure of the gas absorption cell are effectively controlled. This thesis is based on the above key problems. Firstly, a narrow pulse phase-locked amplifier is designed and implemented, which consists of narrow band filter circuit and multiplier circuit. The low pass filter circuit and so on, and carried out the detailed function verification experiment to it, The experimental results show that the narrow-pulse phase-locked amplifier has a good frequency response (center frequency 5k Hz), low bandwidth (bandwidth 80 Hz), high linearity (good fit degree 98.043). Secondly, various parameters of infrared absorption cell are controlled. It includes two parts: temperature control unit and flow control unit. Using Fuzzy-PID compound control theory, the temperature control experiment of stainless steel airtight chamber is carried out. The experimental results show that the temperature control system has fast response speed (response time 7 mins) and low steady-state error (control accuracy 鹵0.2 鈩，

本文編號(hào)：1629098