Fuzzy Control for a Variable Speed Refrigeration System

In this paper, the fuzzy control with feed forward compensator has been presented to save energy and improve COP in a variable speed refrigeration system. The capacity and superheat are independently controlled by an inverter and an electronic expansion valve, respectively. By adopting the fuzzy scheme, incorporating human knowledge, the control system for the capacity and superheat can be designed without an exact dynamic model of the system. Moreover, the feed forward compensator can reduce the direct influence of the interfering loop between capacity and superheat on the system performance. Finally, it can be concluded that the fuzzy controller with the compensator offers good control performances for the complicated refrigeration system against inherent strong non-linearity as well as disturbances.