Desigen Of Switching Optimal Controller For Air-conditioning System

In this thesis,the HVAC system is studied,and the basic structure and working principle of the air conditioning system are analyzed in detail.Bacause the control of the evaporation temperature and superheat is an important part of the air conditioning system control,so control the evaporation temperature and superheat in fast and stable is the key to achieve effective operation of the air conditioning system.Based on the basic working principle of the air conditioning system,a 5 order dynamic nonlinear lumped parameter model of the air-conditioning refrigeration system is established.In order to simplify the design of the controller,a linear state space model of the air conditioning system is obtained by linearizing the nonlinear system model at the selected stable operating point.In order to avoid the error caused by linearization of the modeling and the poor control effect,this thesis adopts the basic idea of switching control,and chooses linearization at multiple operating points for the nonlinear model of air conditioning,and then a set of linear state space model of control systems is obtained.Then the linear quadratic optimal controller for state adjustment problem is designed for each linear sub-model,and the switching rules of the switching control of the air-conditioning system are designed according to the actual system operation.In order to ensure the stable operation of the control system,the stability of the system is verified by the Common Lyapunov Function method,and so the design of the optimal switching controller of the air conditioning system is completed.Finally,in order to test the control performance of the closed-system,this thesis uses MATLAB to simulate under multiple operating conditions,and the simulation results show that the optimal swithing control of the air conditioning system has good control effect.