Limit Protection in Gas Turbine Engines Based on Reference and Extended Command Governors

Abstract

The paper considers the application of Reference Governors (RG), Command Governors (CG) and Extended Command Governors (ECG) to limit protection in gas turbine engines. The governors are add-on schemes to the nominal control design that operate by exploiting physical models of the constraints and predictively modifying the reference commands (set-points) to closed-loop systems as necessary to avoid constraint violation. It is shown that CG and ECG result in comparable speed of response, and both outperform the conventional RG. All three schemes have large constrained domains of attraction. The transient performance improvements in the CG and ECG cases are obtained at the expense of increased computing effort to solve a larger dimensional quadratic programming problem. Measured parametric uncertainties, unmeasured parametric uncertainties, time-varying disturbances and computational complexity reduction are addressed.