【摘要】：在食品加工業(yè)、工業(yè)生產(chǎn)和制藥等領(lǐng)域內(nèi),超低溫的應(yīng)用廣泛,如高商品附加值的海產(chǎn)品速凍儲(chǔ)運(yùn)、生物藥品的生產(chǎn)與儲(chǔ)運(yùn)、低溫生物制品的保存等都需要提供低溫環(huán)境保障其順利進(jìn)行。制冷系統(tǒng)的正常而高效的運(yùn)行是保證其能夠提供穩(wěn)定且達(dá)標(biāo)的低溫環(huán)境的重要因素。在蒸汽壓縮式制冷系統(tǒng)中,除了壓縮機(jī)、蒸發(fā)器和冷凝器,節(jié)流機(jī)構(gòu)是制冷系統(tǒng)中一個(gè)重要的組成部分,其主要作用包括節(jié)流降壓,調(diào)節(jié)制冷工質(zhì)流量和保持合理的系統(tǒng)過熱度。在制冷系統(tǒng)中,節(jié)流機(jī)構(gòu)的運(yùn)行狀態(tài)以及與系統(tǒng)其他部件的匹配程度影響著制冷系統(tǒng)的性能和穩(wěn)定性。目前超低溫制冷系統(tǒng)中常用的節(jié)流機(jī)構(gòu)有熱力膨脹閥和電子膨脹閥,由于機(jī)械結(jié)構(gòu)和工作原理的不同,電子膨脹閥具有熱力膨脹閥不可比擬的優(yōu)勢(shì),如反應(yīng)迅速、調(diào)節(jié)精確等。本課題在搭建節(jié)流機(jī)構(gòu)軟硬件平臺(tái)的基礎(chǔ)上,研究對(duì)比了低溫工況下對(duì)兩種節(jié)流機(jī)構(gòu)的性能,提出了電子膨脹閥的脈寬調(diào)制控制,并采用模糊控制算法進(jìn)行優(yōu)化,選擇出低溫工況下更適宜的控制方式,為今后各類超低溫制冷系統(tǒng)電子膨脹閥的控制研究提供一定的參考依據(jù)。本文研究的主要內(nèi)容及結(jié)論如下:(1)實(shí)驗(yàn)裝置的硬件搭建。主要包括:復(fù)疊式制冷系統(tǒng)低溫級(jí)熱力膨脹閥和電子膨脹閥的選型;數(shù)據(jù)采集系統(tǒng)硬件平臺(tái)的搭建,包括PLC、溫度/壓力傳感器和質(zhì)量流量計(jì)的選取,構(gòu)建基于OPC協(xié)議的PLC與上位機(jī)程序LabVIEW通信;電子膨脹閥控制系統(tǒng)硬件平臺(tái)的搭建,包括PLC和溫度/壓力傳感器的選取,基于OPC協(xié)議的PLC與上位機(jī)程序LabVIEW通信;(2)實(shí)驗(yàn)裝置控制系統(tǒng)的軟件設(shè)計(jì)。主要包括:超低溫冷庫(kù)制冷監(jiān)控系統(tǒng)的軟件設(shè)計(jì)與開發(fā),實(shí)現(xiàn)了對(duì)超低溫復(fù)疊制冷系統(tǒng)的運(yùn)行監(jiān)控以及數(shù)據(jù)采集;電子膨脹閥控制器的軟件設(shè)計(jì)與開發(fā),完成了電磁式電子膨脹閥PWM控制的PLC程序開發(fā),實(shí)現(xiàn)了對(duì)電磁式電子膨脹閥的PWM控制;電子膨脹閥控制系統(tǒng)的優(yōu)化,針對(duì)制冷系統(tǒng)的非線性特點(diǎn),使用模糊控制對(duì)電子膨脹閥控制系統(tǒng)進(jìn)行了優(yōu)化,以滿足蒸發(fā)器出口過熱度的控制要求。(3)低溫工況下電子膨脹閥的實(shí)驗(yàn)研究。首先以系統(tǒng)穩(wěn)定性和系統(tǒng)性能為標(biāo)準(zhǔn),通過實(shí)驗(yàn)確定最適宜的占空比范圍為30%~50%。使用設(shè)計(jì)開發(fā)后的兩套電子膨脹閥控制系統(tǒng),通過實(shí)驗(yàn),測(cè)試和驗(yàn)證了兩套控制器的控制性能。分別開展了對(duì)目標(biāo)過熱度的跟蹤響應(yīng)性能以及對(duì)外界擾動(dòng)的抑制性能的實(shí)驗(yàn)研究。結(jié)果顯示,在目標(biāo)過熱度跟蹤性能方面,模糊邏輯控制器的超調(diào)量平均比PWM控制低5.1%,調(diào)節(jié)時(shí)間平均少220s,上升時(shí)間平均長(zhǎng)80s,絕對(duì)誤差積分平均低0.55,時(shí)間乘以絕對(duì)誤差積分平均小1295.2;在擾動(dòng)抑制性能方面,模糊邏輯控制器的超調(diào)量平均比PWM控制低1.2%,調(diào)節(jié)時(shí)間平均少150s,上升時(shí)間平均長(zhǎng)75s,絕對(duì)誤差積分平均小0.71,時(shí)間乘以絕對(duì)誤差積分平均小1474.7。因此模糊控制器均有明顯的優(yōu)勢(shì)。(4)復(fù)疊式制冷系統(tǒng)低溫級(jí)電子膨脹閥與熱力膨脹閥對(duì)比研究。使用優(yōu)化后的模糊控制器與熱力膨脹閥進(jìn)行對(duì)比實(shí)驗(yàn),測(cè)試低溫工況下,電子膨脹閥與熱力膨脹閥對(duì)過熱度的控制性能。分別進(jìn)行了-50℃、-55℃和-60℃三種不同低溫工況以及變負(fù)荷工況下兩種節(jié)流機(jī)構(gòu)的控制性能對(duì)比。實(shí)驗(yàn)結(jié)果表明相較于熱力膨脹閥,采用模糊控制器的電子膨脹閥在三種低溫工況下,蒸發(fā)溫度平均高5.8℃,但降溫時(shí)間平均快1.73h,同時(shí),過熱度的變化更為穩(wěn)定和平順,壓縮機(jī)排氣溫度和壓力更低,最后,三種工況下的COP平均比采用熱力膨脹閥高10.5%;在變負(fù)荷工況下,采用電子膨脹閥的系統(tǒng)過熱度平均最大波動(dòng)為1.75K,平均調(diào)節(jié)時(shí)間為510s,而采用熱力膨脹閥為3.5K和735s,采用熱力膨脹閥時(shí),低溫級(jí)壓縮機(jī)排氣溫度和蒸發(fā)器進(jìn)口溫度變化更為劇烈,因此,采用模糊控制器的電子膨脹閥對(duì)系統(tǒng)穩(wěn)定性和系統(tǒng)性能方面都有明顯的優(yōu)勢(shì),更適合本超低溫冷庫(kù)制冷系統(tǒng)。
[Abstract]:Ultra-low temperature is widely used in food processing industry, industrial production and pharmaceutical industry, such as high value-added seafood quick-freezing storage and transportation, bio-pharmaceutical production and storage and transportation, cryogenic bio-products preservation and so on. In a vapor compression refrigeration system, throttling mechanism is an important part of the refrigeration system besides compressor, evaporator and condenser. Its main functions include throttling and pressure reduction, regulating refrigerant flow and maintaining a reasonable system superheat. The performance and stability of the refrigeration system are affected by the running state and the matching degree with other parts of the system. Thermodynamic expansion valve and electronic expansion valve are commonly used in the ultra-low temperature refrigeration system. Because of the different mechanical structure and working principle, electronic expansion valve has incomparable advantages, such as reaction. On the basis of setting up the software and hardware platform of throttling mechanism, this paper studies and compares the performance of two kinds of throttling mechanism under low temperature condition, puts forward the pulse width modulation control of electronic expansion valve, and uses fuzzy control algorithm to optimize, chooses the more suitable control mode under low temperature condition, for all kinds of ultra-low in the future. The main contents and conclusions of this paper are as follows: (1) Hardware construction of the experimental device. It mainly includes: selection of low-temperature thermal expansion valve and electronic expansion valve of cascade refrigeration system; construction of hardware platform of data acquisition system, including PLC, temperature/pressure transmission. Selection of sensors and mass flowmeters, construction of PLC based on OPC protocol and host computer program LabVIEW communication; electronic expansion valve control system hardware platform, including the selection of PLC and temperature/pressure sensors, PLC based on OPC protocol and host computer program LabVIEW communication; (2) experimental device control system software design. Software design and development of refrigeration monitoring system for cryogenic cold storage have realized the operation monitoring and data acquisition of super-low temperature cascade refrigeration system; software design and development of electronic expansion valve controller have completed the development of PLC program for PWM control of electromagnetic electronic expansion valve, and realized the PWM control of electromagnetic electronic expansion valve; electronic expansion valve has been realized. According to the non-linearity of refrigeration system, fuzzy control is used to optimize the control system of electronic expansion valve to meet the control requirements of the superheat at the outlet of evaporator. The suitable duty cycle range is 30%~50%. Using the two sets of electronic expansion valve control systems designed and developed, the control performance of the two sets of controllers is tested and verified through experiments. In terms of performance, the overshoot of the fuzzy logic controller is 5.1% lower than that of the PWM controller, 220 seconds less than that of the PWM controller, 80 seconds longer than the rise time, 0.55 lower than that of the absolute error integral, 1295.2 smaller than that of the time multiplied by the absolute error integral. The average rise time is 75s, the average absolute error integral is 0.71, and the average absolute error integral is 1474.7. Therefore, the fuzzy controller has obvious advantages. (4) Comparing the low temperature electronic expansion valve and the thermal expansion valve of cascade refrigeration system. The control performance of the electronic expansion valve and the thermal expansion valve to the superheat was tested under the condition of low temperature. The control performance of the electronic expansion valve and the thermal expansion valve were compared under the condition of - 50, - 55, and - 60. The average evaporation temperature of the valve is 5.8, but the cooling time is 1.73 H. At the same time, the change of the superheat degree is more stable and smooth, and the exhaust temperature and pressure of the compressor are lower. Finally, the COP of the three working conditions is 10.5% higher than that of the thermal expansion valve. The average maximum fluctuation is 1.75K, the average adjustment time is 510s, and the thermal expansion valve is 3.5K and 735s. When the thermal expansion valve is used, the exhaust temperature and the inlet temperature of the evaporator of the cryogenic compressor change more dramatically. Therefore, the electronic expansion valve with fuzzy controller has obvious advantages in the stability and performance of the system. It is more suitable for the cryogenic cold storage refrigeration system.
【學(xué)位授予單位】：上海海洋大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB657

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 芮勝軍;張華;賀滔;羅浩;;自動(dòng)復(fù)疊制冷系統(tǒng)非共沸混合工質(zhì)組分變化特性[J];制冷學(xué)報(bào);2016年04期

2 郭耀君;謝晶;朱世新;王金鋒;;回?zé)崞鲗?duì)雙級(jí)壓縮和復(fù)疊式壓縮制冷系統(tǒng)影響的分析[J];化工進(jìn)展;2016年02期

3 陳明鋒;楊昭;陳愛強(qiáng);張娜;趙松松;劉興華;;制冷系統(tǒng)變?nèi)萘恐悄芸刂频睦碚摷皩?shí)驗(yàn)研究[J];制冷學(xué)報(bào);2015年03期

4 郭耀君;謝晶;朱世新;王金鋒;湯元睿;;超低溫制冷裝置的研究現(xiàn)狀和進(jìn)展[J];食品與機(jī)械;2015年01期

5 趙敏;賈曉龍;;基于遺傳算法的制冷系統(tǒng)動(dòng)態(tài)矩陣控制[J];信息技術(shù);2014年08期

6 董長(zhǎng)盛;郭曉鈴;彭軍皓;;熱力膨脹閥容量測(cè)試系統(tǒng)的設(shè)計(jì)[J];工業(yè)儀表與自動(dòng)化裝置;2014年04期

7 尹珊波;;推力液壓系統(tǒng)壓力與速度的復(fù)合控制研究[J];食品與機(jī)械;2014年04期

8 趙敏;賈曉龍;;基于GPC-PID的制冷系統(tǒng)過熱度控制器[J];信息技術(shù);2014年06期

9 司春強(qiáng);唐俊杰;馬進(jìn);王昕;;我國(guó)氨系統(tǒng)冷庫(kù)安全現(xiàn)狀及發(fā)展建議[J];制冷技術(shù);2014年03期

10 葉奇f ;劉杰;陳江平;;蒸發(fā)器與熱力膨脹閥回路穩(wěn)定性研究[J];制冷技術(shù);2013年04期

相關(guān)會(huì)議論文 前2條

1 劉學(xué)浩;孫天臻;邵偉;;冷庫(kù)應(yīng)加快實(shí)現(xiàn)自動(dòng)化控制及微機(jī)的應(yīng)用[A];中國(guó)制冷學(xué)會(huì)第十七次團(tuán)體會(huì)員大會(huì)暨第五屆全國(guó)食品冷藏鏈大會(huì)論文集[C];2004年

2 楊富華;孟運(yùn)蟬;;超低溫冷藏系統(tǒng)[A];中國(guó)食品冷藏鏈新設(shè)備、新技術(shù)論壇論文集[C];2003年

相關(guān)碩士學(xué)位論文 前8條

1 郭曉鈴;熱力膨脹閥容量測(cè)試系統(tǒng)的研制[D];中國(guó)計(jì)量學(xué)院;2014年

2 高若楠;調(diào)節(jié)范圍擴(kuò)大下熱力膨脹閥感溫包充注介質(zhì)及組分研究[D];浙江大學(xué);2014年

3 李兆博;制冷機(jī)雙回路節(jié)能控制方法的研究與實(shí)現(xiàn)[D];天津大學(xué);2012年

4 丁凡利;基于PROFIBUS-DP現(xiàn)場(chǎng)總線的千噸冷庫(kù)制冷自動(dòng)控制系統(tǒng)設(shè)計(jì)[D];山東大學(xué);2012年

5 李麗芬;熱力膨脹閥選型方法研究及對(duì)系統(tǒng)可靠性的影響[D];上海交通大學(xué);2008年

6 張?chǎng)?基于LabVIEW的熱電空調(diào)溫度模糊控制系統(tǒng)的研究[D];大連海事大學(xué);2008年

7 潘永平;冷庫(kù)制冷系統(tǒng)多變量自適應(yīng)模糊控制研究[D];廣東工業(yè)大學(xué);2007年

8 潘武平;基于OPC協(xié)議的數(shù)據(jù)通信[D];北京化工大學(xué);2004年

，

本文編號(hào)：2182427