Research On Constant Temperature Control Of Gas Water Heater Based On Grey Prediction And Extension Control

Gas water heater is a kind of small domestic thermal equipment.It uses domestic gas as fuel to heat through continuous combustion of gas.Through heat conduction,heat radiation and other heat transfer methods,the combustion heat is transferred to the cold water of heat exchanger,so as to achieve the purpose of heating cold water.In order to solve the problems of long response time,large overshoot and insufficient heat preservation performance of gas water heater in heating or cooling stage,this paper proposes an adaptive grey prediction extension control method based on the temperature control system of gas water heater.The control effect of this method is studied by computer simulation,and the adaptive grey prediction is realized by C language programming The extension control algorithm is written into the microprocessor of gas water heater for experimental verification.Firstly,by analyzing the principle of the combustion system of the gas water heater and the main parameters affecting the outlet water temperature,the mechanism model of the gas water heater is established.Because the mechanism modeling is based on certain assumptions,the parameters of the model change with the change of water flow and gas pressure.If the model is regarded as a constant for the convenience of the establishment of the model,it will lose its guiding significance to the reality.In this case,the model accuracy of least square method and genetic optimization algorithm is studied by collecting experimental data.Then,based on the system model,MATLAB / Simulink is used for modeling and simulation,and the simulation results are compared with the conventional PID,extension control,grey prediction PID control and grey prediction extension control.The simulation results show that,compared with conventional PID control,extension control,grey prediction PID control and grey prediction extension control,adaptive grey prediction extension control has better control effect.The adaptive grey prediction extension control proposed in this paper can effectively improve the stability of effluent temperature control,reduce the temperature regulation time and overshoot,and has strong anti-interference ability.Finally,in order to realize the real-time monitoring of the running state parameters of the gas water heater,the upper computer monitoring interface is developed by using Lab VIEW development environment to realize the communication between the monitoring software and the single chip microcomputer.At the same time,based on the Risa MCU control chip,the adaptive grey prediction extension control algorithm is realized by using C language script programming.In view of the limited computing power of Renesas microcontroller,the nonlinear extension control algorithm is improved to linear extension control,and applied to the constant temperature control of gas water heater outlet temperature,which reflects the portability of the algorithm.The experimental results show that the adaptive grey prediction extension control has good control performance...