A Self-Tuning Fuzzy Logic Controller for Superheat of Evaporator by Using Electronic Expansion Valve

Abstract

In this paper, a self-tuning fuzzy logic controller (STFLC) is proposed to maintain the evaporator superheat via an electronic expansion valve (EEV) in a vapor compression chiller system. The output scaling factor (SF) of the STFLC is tuned in an on-line manner by fuzzy rules according to the current condition of the process. To verify the performance of the proposed control scheme, real-time experiments have been conducted on a pilot vapor compression chiller system. The results demonstrate that the controller design outperforms its conventional counterpart in keeping the evaporator superheat at a desired value even when the refrigeration load is changed over a wide range.