Research Of VAV Terminal Simulation And Control Based On Generalized Predictive Self-Tuning Controller

Nowadays, Variable Air Volume (VAV) air-condition system has gradually become most popular in China and abroad because of its significant energy saving. However, VAV air-conditioning system has characteristics of strong nonlinear, large delay, time-varing, it is difficult to gain the precise mathematical model by using the traditional linear control theory, such as PI, PID. So its control performance, Energy -saving and comfort are poor. At the same time, with the improvement of living standards, people request for the higher indoor thermal comfort. However, the control project in which the indoor temperature is unique controlled parameter is not enough, it is difficult to create a comfortable environment.In response to these questions, this paper takes the VAV terminal as the object for studying and designs a VAV terminal control system. The system put thermal comfort index as indoor control parameter and select generalized predictive self-tuning algorithm as the control methods. By analyzing thermal comfort factors, this paper select PMV index as control parameter. Thermal comfort index control is adopted, the object of system control will change from indoor air to occupants. Thus the thermal comfort level will be improved and the potential for energy conservation can be boosted. According to the characteristics of strong nonlinear, large delay of VAV system, this paper designed a time-varying forgetting factor for parameter estimation of generalized predictive self-tuning controller based on the traditional self-tuning generalized predictive control method. This method can adjust forgetting factor with the systematic dynamic characters automatically, modify model error in time to improve predictive precision and guarantee control effect. In order to avoid a large amount of computation, implicit algorithm is used to solve the generalized predictive output.In order to verify the reasonableness of the above design and improve the efficiency of system design, this paper designed a real-time online VAV simulation platform based on Matlab and Configuration Software. A simulation experiment was conducted to validate the generalized predictive self-tuning algorithm based on PMV index. The simulation results show that the design of the control method can satisfy people's demand for thermal comfort, and has good control performance, the control performance is better than traditional PID temperature control, and has a certain energy-saving effect.