基于PLC的变频调速恒压供水系统设计

为了提高大范围变负荷恒压供水系统的控制精度和可靠性,提出了采用多台水泵分级控制,轮流变频启动的控制策略,并结合大范围变负荷供水系统的特点对常规PID控制算法作了一些相应的改进;同时,分析了变频器的输出及切换问题,给出了具体的切换方法和控制电路.该系统取代了高塔或水泵直接加压供水方式,提高了供水质量,节能效果明显.

System design of variable-frequency speed governing and constant pressure water supply based on PLC

In order to improve control precision and stability,the control strategy was put forward that several pumps were controlled in grades and freqequency conversion by turns,which applies water supplying systems with constant preasure whose load varies in large range.Meanwhile,several improvements of PID algorithm were made according to characteristics of water supplying whose load varies in large range.At the same time the problem about output and cut-over to frequency converter was analyzed providing specific cut-over methods and control circuits.The system replaced the high tower directly or pressurized water pump.It improves water quality,and energy saving effects obviously,and has high promotion and application value.