Abstract

This study analyzes the behavior of the control valve-positioner system that has large grand friction and examines its control scheme for performance improvement. The authors have confirmed that introducing the PI-D control with a gap in the integrator of position controller and the minor feedback control of the diaphragm pressure is the effective way for the stability and dynamic response of the system. In order to improve the behavior to the small change of the set point, this paper proposes the hysteresis compensation of control valve considering the flow condition and confirms its effectiveness.