Mehdi Moradi - Department of Electrical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Javad Askari - Faculty of Electrical and Computer Engineering, Technical University of Isfahan, Isfahan, Iran
Saeed Hosseinnia - Department of Electrical Engineering, Najafabad Branch, Islamic Azad University, Najafabad

The problem of fuzzy logic surge control in centrifugal compressors is addressed in this paper. A compression system equipped with a close-coupled valve (CCV) and a throttle control valve (TCV) as actuator devices is investigated. With reference to the Gravadahl compressor model, the use of a new control strategy based on active surge control is suggested. In this approach, no control action is taken in the right side of the compressor performance map, but a fuzzy controller actuating CCV and TCV is employed at the left side of the map. The combination of the two control valves proves helpful in suppressing surge and assists in overcoming the drawbacks of using CCV individually. Provided that no change of operating point to the left side of the surge line is desired, only CCV is actuated, otherwise actuating TCV besides CCV will be started. Simulation results show that the proposed control strategy gives promising performance in various situations while extending the stable range well beyond the surge line

Centrifugal compressors, dynamic model, fuzzy logic, control valves