变频恒压供水系统plc控制 论文 大学论文.doc

变频恒压供水系统PLC控制 系 别： 专 业 班： 姓 名： 学 号： 指导教师：  变频恒压供水系统PLC控制 The Control of PLC on Water Supply System of Constant Pressure and Frequency Conversion 摘 要 随着社会经济的迅速发展，人们对供水质量和供水系统可靠性的要求不断提高，再加上目前能源紧缺，利用先进的自动化技术、控制技术以及通讯技术，设计高性能、高节能、能适应不同领域的恒压供水系统成为必然趋势。 该课题分析变频调速恒压供水的原理及系统的组成结构，提出不同的控制方案，通过研究和比较，该课题采用变频器和PLC实现恒压供水和数据传输，然后用数字PID对系统中的恒压控制进行设计。由变频器及PLC组成控制系统，调节水泵的输出流量。电动机泵组由两台水泵并联而成，由变频或工频电网供电，根据供水系统出口水压和流量来控制变频器电动机泵组之间的切换及速度，使系统运行在最合理的状态，保证按需供水。 该课题介绍了采用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。系统通过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 自动调节 Abstract With the rapid development of spcial economy, it demands the better of water supply’s quality and reliability of water supply system. Meanwhile energy resources are seriously lack. So it is inevitable tendency to design water supply system which has high function and saves on energy well, with help of advanced technique of automation, control and communication. At the same time this system can adapt different water supply fields. This paper analyzes the structure of VF speed regulating constant-pressure water supply,and proposes several control methods.By careful study and comparison, PLC and inverters method fits water supply system and datatransmission very well. It is very important of the Water Supply System in Constant Pressure for the water supply in industrial and citizen existence. It is consist of the variable frequency and speed regulation,PLC,for the control system. It controls the outcome of the pumps. The generator pumps are consisting of parallel three pumps, and the power come from variable frequency and speed regulation or power grid. According to the water supply of constant perssure’s outcome water press and flux, the control the variable frequency and speed regulation, parallel pumps’ speed and cut over, cause the system move in the best rational situation, assure according to wants supply water. This design has many merits such as save energy. In this paper, the