Rotating Stall Control in Axial Compressor Subject to Wheel Speed Transients

Abstract

A gain-scheduled controller design methodology for rotating stall control in an axial flow compressor subject to wheel speed transients is presented. Linear robust controllers are designed for a family of flow coefficients in the spatial domain at specified discrete wheel speeds to regulate nonaxisymmetric flow. The resulting family of controllers are then gain scheduled with respect to wheel speed in an effort to address the transient wheel speed condition. To validate the performance of the gain schedule control law, domains of attraction obtained from initial condition simulated responses of the nonlinear compressor model are used. I. Introduction R OTATING stall and surge are aerodynamic instabilities that occur during operation of a compressor near the peak pressure rise of the compressor. These instabilities degrade performance and produce large loading effects on the compressor blades. To avoid the occurrence of these flow instabilities, the compressor is operated at conditions that are removed from the surge line (stability line), thus creating a factor of safety defined as the surge margin. The surge margin required to prevent the occurrence of rotating stall and surge during wheel speed transients is related to the rate of change