Temperature control in a cavity of refrigeration using PI controller and predictive control

A PI controller and a generalized predictive control strategy of the temperature inside a cavity of refrigeration are proposed, using Matlab/Simulink environment. The control strategies were applied to a third-order discrete state space system, which computes the internal air temperature according to the temperature at the level of the evaporator exchanger, under the influence of the ambient temperature. The system was obtained by linearization of a pseudo bond graph model of thermal transfers inside the refrigeration cavity. The simulation results were compared to those of the pseudo bond graph model for a classical thermostatic control. The used control strategies allowed an average energy saving of about 70% compared with the conventional on/off controller. The predictive control was more efficient than the PI controller of 23.33 %.