Design of Chemical Water pH Control System in Thermal Power Plant Based on Fuzzy PID

As the country continues to progress and electricity demand increases, thermal power plants are subject to heightened requirements for power generation. Consequently, power plant equipment demands higher standards of water quality. Maintaining an appropriate pH value in boiler water is crucial as it protects equipment, enhances thermal efficiency, and ensures safe and stable operation. Therefore, controlling the pH of boiler water is of significant importance in the operation of thermal power plants. This paper investigates the pH dosing control component within the water treatment systems of thermal power plants and analyzes and designs the associated control process. Initially, the research background and current state are examined. Subsequently, the furnace water treatment process is analyzed, and an overall control method is designed. The control system for the internal water of thermal power plants is developed using PLC and HMI software, with Siemens S7-1200 PLC selected as the main controller. Its hardware configuration is determined by writing control programs in PLC and integrating HMI software for signal acquisition and processing to achieve system control and status monitoring. The control system employs PID control to adjust the frequency converter’s output, regulating the valve opening of the electric dosing valve, and the dosing flow rate to manage the boiler water’ s pH. Two control schemes, conventional PID and fuzzy PID, are evaluated. A control simulation model is established in Simulink with MATLAB for comparative analysis, confirming the feasibility of fuzzy PID control. Fuzzy PID control demonstrates enhanced adaptability and superior performance compared to traditional PID control.