GPC Based PID Control for Superheat Control of Refrigeration System

Superheat control of refrigeration system features large time-delay. When the operation conditions change, it is difficult for a traditional PID controller with fixed parameters to achieve ideal control effects. Consider the advantage of traditional PID and generalized predictive control (GPC) algorithm, a new PID algorithm based on GPC is proposed in this paper. After obtaining the system model by using the least square identification, the solution of Diophantine equation is used for the PID parameters, which can change adaptive according to the operation conditions. And the simulation results in the last part of the paper prove the efficiency of strategy.