Positive feedback stabilization of compressor surge

Abstract

Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the onset of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is nominally closed and only opens to stabilize the system around the desired operating point. Hence, only non-negative control values are allowed which complicates the controller design considerably. A novel positive feedback controller is proposed with clear design parameters to obtain a desirable closedloop behavior. The technique has successfully been applied to a compression system model. For arbitrarily large control valve capacities, the system can be stabilized in the entire operating region. Simulations show that the surge point mass flow can be reduced up to 15% for the relatively small control valve to be implemented on the actual installation. Using this efficient control strategy, the stabilized operating point is reached with zero control valve mass flow.

Stabilizing Hybrid Control Laws

“…In (Willems et al, 1999) the problem of positive feedback stabilization of surge in compressors is treated.…”

“…for some positive constants « ® , ± and (We refer to (Willems et al, 1999) for precise physical interpretations of the parameters and state variables). We denote the equilibrium point of system around this equilibrium point is given by:…”

“…(Saperstone, 1973) for a related controllability result. In this paper we will briefly discuss an example of positive control, found in the study of surge control for compressors, see (Willems et al, 1999).…”

Surge Onset in Turbo Heat Pumps

“…Gysling [5] conducted a linear stability analysis to investigate the effectiveness of plenum volume variation in stabilizing turbocharger surge. Willems et al [6] focused on active surge control of a compression system in the presence of valve saturation and valve dynamics.…”

A separation principle for non-UCO systems: The jet engine stall and surge example

“…Since its development, several researchers have used the Moore-Greitzer three state model (MG3) to design stabilizing controllers for stall and surge. The available control approaches may be divided into three main categories: 1) Linearization and linear perturbation models (e.g., [21,18,5] among others); 2) Bifurcation analysis (e.g., [11,12,6,16,1]); and 3) Lyapunov based methods (e.g., [8,4,20]). Most existing results focus on the development of state feedback controllers which may not be implementable.…”