University of California

United Technologies Corporation

Miroslav Krstic

Youping Zhang

Andrzej Banaszuk

Clas A Jacobson

Arthur J Krener

A frequency tracking extended Kalman filter ( ), responsive to combustor pressure ( ), produces in-phase ( ) and quadrature ( ) components of the estimated magnitude of the undesirable combustor pressure variations, for which compensation is to be achieved; a bidirectional minimum-seeking algorithm ( ) is used to select the phase ( ) of a process adjusting input variable ( ), such as fuel that is in addition to the main fuel flow used for power control purposes.

Suppressing oscillations in processes such as gas turbine combustion

A method and apparatus for predicting the onset of stall in an axial flow compressor and stabilizing stall so as to achieve the maximum pressure rise to the combustor. Stall in an axial flow compressor is predicted by obtaining pressure or axial velocity measurements at a plurality of circumferential angles around a compressor stage, fourier transforming the measurements with respect to the circumferential angles to obtain a time history of the zeroth, first and higher modes, and determining amplitude gain at twice the rotor frequency of the transfer function from the product of the zeroth and first modes to the first mode, with an increase in amplitude gain depicting a right skewed compressor going into stall and a decrease in amplitude gain depicting a left skewed compressor going into stall. Rotating stall and surge in the compressor is stabilized so that the pressure rise to the combustor can be maximized by creating an oscillatory motion of the pressure and feeding said oscillatory motion back to vary the set point of an extremum seeking controller, wherein an internal rotating stall and surge feedback loop in said controller that stabilizes said compressor is closed and wherein an outer extremum seeking loop in said controller which maximizes the pressure rise is closed.

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San Diego, CA, United States of America

Miroslav Krstic