Improved Smith predictive compensation and decoupling in refrigeration system
制冷系统的改进Smith预估补偿和解耦控制

Firstly, a model identification of refrigeration system is carried out on the basis of experiment to obtain a second-order transfer function matrix with dual-input and dual-output, which is then verified. Secondly, an improved Smith predictive compensation and decoupling control are developed for the refrigeration system and simulated. Finally, the dual closed-loop control system consisting the variable minimal superheat-control and constant evaporation temperature-control is proposed. Besides, an experimental method to obtain the minimal superheat curve is developed. Compared with the PID control, this method provides better steady and dynamic performances in strong coupling, delay and inaccuracy in the identification model, and meets with the control requirements in variable load and variable minimal superheat.