Multivariable IMC-PID within air-conditioned room temperature and relative humidity control system

Aiming at the problem that central air-conditioning system can´t operation stably with the large hysteresis and the circuit coupling of temperature and relative humidity, this paper presents a method for controlling the temperature and relative humidity of air-conditioned rooms with IMC-PID controller for the multivariable system. Air-conditioned room is the research object of this paper. First, get the temperature and relative humidity step response curve of air-conditioned room, in order to establish the system transfer function matrix. Then design a multivariable decoupling IMC controller of this system. Finally, to make the controller easy to use in practical projects, this paper integrates the IMC controller and object model as an IMC-PID controller. MATLAB simulation results show that this method can solve the problem that temperature and relative humidity is coupled. In the case of model mismatch, the controller can still achieve better control effect than conventional PID control.