Design of controllers for MG3 compressor models with general characteristics using graph backstepping

We discuss the design of controllers for compressors with general characteristics using a graph backstepping procedure involving the construction of the throttle surface. We show that for a quite general compressor characteristic, every potential axisymmetric equilibrium on the decreasing part of the compressor characteristic, the peak of the characteristic, and every rotating stall equilibrium close to the peak can be globally stabilized by an appropriate choice of the throttle surface and the controller gains. We discuss controllers that stabilise a range of the desired equilibria and guarantee a soft bifurcation of the equilibria as a set-point parameter varies