Model based MIN/MAX override control of centrifugal compressor systems

TL;DR

This paper presents a nonlinear control approach for centrifugal compressors that ensures operation within safety limits by integrating a modified compressor model with MIN/MAX-override control and output regulation techniques.

Contribution

It introduces a novel control scheme combining a modified compressor model with MIN/MAX-override control and output regulation for industrial compressor safety and performance.

Findings

Successful implementation of discharge pressure control

Effective anti-surge control demonstrated

Operation within maximum discharge pressure limits

Abstract

We consider an application-oriented nonlinear control of centrifugal compressors. Industrial applications require the compressor system to adjust to variable process demands and to be restricted to the valid operation range (e.g. surge limit). We modify a compressor model of Gravdahl and Egeland to account for characteristic features of industrial compressors and combine the framework of nonlinear output regulation via the internal model principle with MIN/MAX-override control in order to implement trajectory tracking between given state constraints. Furthermore the switching scheme as well as the practical stability of the closed-loop MIMO system is analysed by the corresponding switched and impulsive error system. The override control is demonstrated by applying discharge pressure control, anti-surge control and maximum discharge pressure limitation.