Research On Temperature And Humidity Control Of VAV Air-conditioning System Based On ILC And MPC

Currently, the main problems facing the air conditioning system are that how to improve the comfort of the indoor environment and how to reduce the energy consumption of air conditioning. The above problems are solved by using variable air volume air conditioning system, which maintain stable indoor environment by adjusting the size of the air supply,according to the indoor load size. However, the traditional VAV control methods face two problems, one is that the traditional controllers need high precision mathematical model, and the other is that their structure are complicated, and also with a poor control accuracy and anti-interference ability. The above disadvantages restrict the VAV system to apply in reality environment. Therefore, how to improve the VAV system anti-jamming capability has very important theoretical and practical value.In order to solve the problem that temperature and humidity control of VAV systems both encounter interference present in the repetitive interval between each fixed time and encounter non repetitive interference problems exist within a certain time interval, this thesis studies the VAV temperature and humidity control based on iterative learning control and predictive control.The details of the thesis are as follows:1. By using the principle of VAV temperature and humidity control, we establish a mathematical model of the temperature and humidity control system.2. A simulation example shows that iterative learning control can improve the control accuracy of humidity control loop as well as the response speed.3. For non repetitive interference that VAV temperature and humidity control encountered,we propose the iterative predictive control algorithm which combining iterative learning control and predictive control. Then, we give a simulation experiment for a VAV humidity control loop and the results show that our proposed algorithm can improve the system efficiency repetitive interference suppression as well as the system’s ability to suppress non repetitive interference.4. In order to solve the problem of the temperature control loop can be affected by humidity,we first propose a decoupling temperature and humidity control law through the feed-forward compensation method, then apply the iterative predictive control approach to the VAV air-conditioning temperature control system. Simulation results show that the iterative predictive control approach can obtain better control accuracy and response speed, and also it can improve the anti-jamming capability of the system.