Comparison of different controllers for variable speed compressor and electronic expansion valve

This study deals with effects of different control methods on variable speed compressor (VSC) and electronic expansion valve (EEV) in a chiller system. The chiller system has a scroll type VSC and a stepper motor controlled EEV. Two different procedures were applied to control EEV and VSC: controlling each part individually while the other was set to a constant value and controlling both parts together using the same algorithm. Three different control algorithms such as proportional, integral, differential (PID), fuzzy logic and Artificial Neural Network (ANN) were experimented. In the first case, PID controller presented reasonable control solution for more stable SH and T-wo values in the steady state. In the second case, ANN controller pair was selected to achieve minimum power consumption and more stable SH and T-wo values against to a disturbance. In this manner, ANN controller showed lower power consumption of 8.1 percent and 6.6 percent than both PhD and Fuzzy controllers, respectively. (C) 2010 Elsevier Ltd and IIR. All rights reserved.