Design Of Embedded Control System For Gas-Central Water Heater

With gas-central water heaters more and more widely applied in the modern life, the higher request is set to its operating characteristic. The embedded control system is one of the main roles for its performance, and it mainly reflects in the water temperature fast adjustment and the constant temperature control. A new control method combining Fuzzy control, PID control and self-learning is presented in the paper, and it is used in the water heater to realize intelligent control.In the paper, the physical models and control characteristics of the proportional solenoid valve and the blower are studied in detail, and the desirable control methods are presented for them. Based on the research on the gas combustion mechanism, the combustion control system is analyzed. Then, the approximate mathematical model of the controlled object is established. The advantages and disadvantages of the traditional PID, Fuzzy control and neural network control are compared. In this foundation, the intelligent control scheme of the gas water heater is proposed. Fuzzy-PID controller of the gas water heater is designed with emphasis. With the simulation model built up, the further analysis of simulation is processed. The simulation result indicates that Fuzzy-PID control effect is not only obviously superior to both traditional PID and integral separated PID, but without oscillation and static error. Then, self-learning of the system is designed.An implementation scheme taking PIC MCU as the core is given for gas-central water heater. The software and hardware are designed for the control unit of the proportional solenoid valve, the blower and the ignition. In addition, the software architecture of the main program is provided. The communication and power interface circuit in time-sharing are designed with emphasis on communication protocol. The display board designed not only is satisfactory but also cost much low.In brief, the control system designed in the paper not only realizes intelligent control, but also possesses the functions of automatic detection, fault handing and operation mode diversification.