Application Research Of Predictive Control In Gas Boiler Heating System

In recent years, energy saving and emission reduction have become the most important concern of our society. In some big cities, gas-fired boiler is gradually substituting for traditional coal-fired boiler in new heating systems. However, there exists various kinds of shortcomings in current gas-fired boiler heating system, especially the unreasonable control scheme which has caused unnecessary energy waste. In order to improve control performance and reduce the costs, advanced control scheme should be analysed.First, the property of gas fired boiler heating system is analysed. The controlled variable of the system is the secondary circuits return water temperature,and the control variable of the system is the opening of three-way valve. The primary theory of the DMC is addressed in detail with the application of DMC in the boiler heating control system. The dynamic matrix predictive control can be summarized into predictive model, moving optimization, and feedback correction. The dead zone predictive error correction is proposed with the idea of predictive control. Moreover, the system control parameters are initially set up, whose effects on system control are simulated using MATLAB whereby the proper control parameters are finally obtained.Second, the accomplishment of control system is investigated in detail. The system control property, control position and the control points are addressed. According to the control system requirement, control strategies of primary circuits, secondary circuits and water supply pump are established. The controller hardware is configured with control strategy. The function of CPU module and extension modules of the controller are also investigated. Furthermore, the function, which consists of real-time display, data storage based on database, real-time control, system alert and web publishing based on ASP.NET, required in developing upper computer software and its accomplishment method are also discussed in detail. The control function is programmed using both MATLAB and VB, and thus the application of DMC in upper computer and valid real-time control calculation is accomplished.Finally, the effects of the control system is validated by means of the hardware-in-the-loop simulation in which the signal is generated and acquired through computer interface card system in order to simulate the real operation condition and the physical part is the controller for the reason that the system could be operated under closed loop condition. According to the design of the experiment, the primary circuits and secondary circuits are set up. The hardware interface circuit and the upper computer simulation system are designed respectively, thus the control system could be tested separately.The application of dynamic matrix predictive control in gas boiler heating control system make the automation level increased greatly, save the energy effectively, and reduce the costs of the users.