The Modeling And Control Of A Big And Medium-sized Refrigeratory

The topic of the dissertation comes from the in actual cold storage project of Guangdong Food & Aquatic Products Import & Export Group of Zhongshan. This paper establish the concentrated parameter model of the refrigeration system first, then choose the ITAE twice optimum control to control the refrigeration system acoording to the model. We can see from the simulation result that diversified dynamic capability target of the system is better than that of the Smith estimate controlled.The refrigeration system of the cold storage is a very complicated energy transmitting system. Established an accurate mathematics model has a very big inflence of the system control and the energy saving effect. This paper established a mathematics model of refrigeration room by the conservation of energy first, then modeling the evaporator by employing least-squares in a broad sense, at the end, modeling the temperature sensor, executant and the piping. Synthetize the model of each part, this paper establish the concentration parameter model of refrigeration system. At this time, we can see that the mathematics model is a high-level, big inertia, large time-delay system.Aim at the high-level, big inertia, large time-delay system, I choose the ITAE twice optimum control to control the system after comparing. Twice optimum control has the good control result on the big inertia, large time-delay system, but the object of this method is one rank inertia add time-delay system. So in chapter 3 I adopt the optimum decline rank method to deduce the refrigeration system model first, and then designed the twice optimum controller with calculation the parameter. At the end, i study the robustness of twice optimum control.For the control strategy that the front choose, the last chapter establishecd the emluate model of twice optimum control in SIMULINK and simulate the system. Since the simulation result can see that the control effect is not too good use the controller with the parameter calculated according to the formula in chapter 3. After adjusted the patameter of the controller tinily, the system has a good control effect. Through comparison with Smith estimate control, especially add disorder input, can see that the system with twcie optimum control has good performance to Smith estimate control. The system's strong robustness is represented when the mathematics model isn't accurate.