毕业论文：变频器恒压供水系统的整体设计.docVIP

PAGE \* MERGEFORMAT II 变频器恒压供水系统的整体设计 摘要 随着社会经济的飞速发展，城市建设规模的不断扩大，人口的增多以及人们生活水平的不断提高，对城市供水的数量、质量、稳定性提出了越来越高的要求。我国中小城市水厂尤其是老水厂自动控制系统配置相对落后，机组的控制主要依赖值班人员的手工操作。控制过程繁琐，而且手动控制无法对供水管网的压力和水位变化及时作出恰当的反应。为了保证供水，机组通常处于超压状态运行，不但效率低、耗电量大，而且城市管网长期处于超压运行状态，曝损也十分严重。 本文介绍了采用PLC控制的变频调速供水系统，由PLC进行逻辑控制，由变频器进行压力调节。在经过PID运算，通过PLC控制变频与工频切换，实现闭环自动调节恒压供水。运行结果表明，该系统具有压力稳定，结构简单，工作可靠等优点。 关键词：变频调速，恒压供水，PID调节，PLC，监控系统 INVERTER CONSTANT PRESSURE WATER SUPPLY SYSTEM ABSTRACT With the rapid socio-economic development，urban construction expanding the scale of population increase and the continuous improvement of living standard of urban water supply quantity，quality，stability，higher and higher requirements.Small and medium cities in China，especially the old water plant water plant control system configuration is relatively backward，the control unit depends on duty personnel manual.Control process is complicated，and can not manually control the pressure of the water supply network and water level changes to make appropriate and timely response.To ensure the water supply unit operating normally in overpressure condition，not only low efficiency，power consumption，and the overpressure of sewer running a long time，exposure is also very serious damage. This paper introduces the PLC-controlled frequency conversion water supply system，conducted by the PLC logic control，pressure regulation by the inverter.After PID operation by PLC control frequency and switching freQuency to achieve closed-loop automatic adjustment of constant pressure water supply.The result shows that the system has pressure stability，simple structure，reliable. Keywords:frequency conversion，constant pressure water supply，PID regulator，PLC，monitor and control-system PAGE \* MERGEFORMAT 1 目录 TOC \o 1-3 \u 摘要 PAGEREF _Toc1554 I ABSTRACT PAGEREF _Toc15909 II 目录 PAGEREF _Toc12664 i 1绪论 PAGEREF _Toc14161 1 1.1城市供水系统的要求 PAGEREF _Toc12030 1 1.2变频调速系统的发展趋势 PAGEREF _Toc29244 3 1.3变频恒压供水产生的背景和意义 PAGEREF _Toc6113 4 1.4国内外研究概况 PAGEREF _Toc