The dynamic mathematical model of a turbine-driven centrifugal compressor was established. A fuzzy PID controller for the compressor was designed and the dynamic response characteristics of the compressor were examined. The results show that the fuzzy PID controller designed can reduce the overshoot of the system dynamic response compared with the conventional controllers and eliminate steady state errors quickly when disturbance occurs

leading to the greater system response speed. Considering the coupling of the compressor flow rate

pressure ratio

and speed

the controller can govern the turbine speed and opening of the anti-surge valve

respectively. Thus the operation point is never located in the surge area and the pressure ratio reaches the set value in 40 s. It seems that the controller developed can improve the control effect and save energy.