Constant Pressure Water Supply Control System Using PLC

With the improvement of residents' living standards,the requirements for the stability of urban water supply systems and energy-saving operations have been gradually increasing.In order to meet the high-quality water supply demand,the variable frequency speed regulation constant pressure water supply system has become the hot research topic.This thesis mainly aims at the variable frequency speed regulation constant pressure water supply system.The dynamic mathematical model is established,and a variable frequency speed regulation method based on fuzzy PID control is developed.The realization of constant pressure water supply control scheme is studied.Specifically,the characteristic curve of the pump operation,the principles of the variable frequency speed regulation and constant pressure water supply are firstly analyzed.Then,the dynamic model of the variable frequency speed regulation constant pressure water supply system is established from the mechanism.According to the established dynamic mathematical model,a constant pressure water supply control algorithm based on fuzzy PID control and its parameters self-tuning method are proposed.The constant pressure water supply system and fuzzy PID control algorithm are simulated by Matlab.The simulation results show that the dynamic mathematical model can describe the constant pressure water supply process well,and the proposed fuzzy PID control method has good control effect.Finally,using a city water supply system as an example,the control system is implemented through the Siemens S7-300 series and WinCC,including PLC selection,I/O configuration,fuzzy PID control algorithm and WinCC configuration design,HMI,etc.The implementation results show that the realization of the S7-300 series PLC and WinCC based on the fuzzy PID control algorithm fully satisfies the demands for constant pressure water supply and energy saving.It provides references for the control of the urban water supply system.