| This thesis is carried out based on the central air-condition control project of a city traffic control center.Automatic control of central air-condition is the main component in the building automation system. The control quality of central air-condition system not only determines comfort degree of air-condition places, but also has a direct effect on the level of energy consumption of building. Currently the traditional PID control is used in the central air-condition system. However, the central air-condition system is a complex system which is more interference factors, strong nonlinear, heavy coupling between the loops, PID control mode is almost unable to achieve more efficient, less energy consumption performance index. Intelligent control technology needn't a precise mathematical model, which is especially suitable for complex applications such as central air-condition system. The combination of expert control technologies and traditional PID control is used in this paper. This system improved the dynamic and static state performance of central air-condition system, had a significant effect on energy savings and, had a certain project practical value and theoretical research value academically.The paper analyzed rationale and basic thought of expert control together with control target, explained the basic structure and its characteristics of expert control system emphatically, as well as the design principles and basic requirements of an expert controller; the operating principle of central air condition system together with its controlled object and control target was analyzed ; PID control mode which is used in the central air-condition system currently and its existent problem were discussed; The main contribution was listed as follows: Combined with the actual project, demonstrated the feasibility of adopting real-time expert control technology to the central air-condition system, combining expert control technologies and traditional PID control was applied to construct the central air-condition expert control system, including the design of system structure,logical partition of control area, and configuration design of relevant hardware; established software frame of control system; adopted siemens Step7 to program MMI controller at the scene,meanwhile adopted OPC technology to realize the communication of WinCC real-time database and local control layer; the author still set up control regulation set(5 subsets, decades of regulations) and control flows; devised total database[expert control] of central air-condition expert control system with SQL... |
