Compressor surge active control via throttle and CCV actuators. A second-order sliding-mode approach

In this paper we address the problem of active surge control in compressor systems by using a Close-Coupled Valve (CCV) and a Throttle Valve (TV) as actuator devices simultaneously acting on the compressor. With reference to the Moore-Greitzer compressor model, we suggest the use of a second-order sliding-mode (2-SM) technique. We show that the proposed control system can stabilize any desired operating point belonging to some region in the state plane by rejecting a significant class of persistent pressure and flow disturbances acting on the system. The perfect knowledge of the compressor and load characteristics is not required to design the controller, and, furthermore, the unmodelled actuator dynamics are taken into account explicitly in the stability analysis.