Patent ID: 8215095

Claim:
A control system for a gas turbine, including: a fuel control actuator; a combustion air control actuator; a speed sensor that senses a rotational speed of the gas turbine; a temperature sensor that senses exhaust temperature of the gas turbine; and a coordinated air-fuel controller that controls operations of the fuel control actuator and the combustion air control actuator, wherein the coordinated air-fuel controller receives a first input signal from the speed sensor and a second input signal from the temperature sensor, and wherein the coordinated air-fuel controller further includes: a rotational speed error calculator that determines a rotational speed error based on the first input signal from the speed sensor and a speed reference; an exhaust temperature error calculator that determines an exhaust temperature error based on the second input signal from the temperature sensor and a temperature reference; a fuel controller that provides a fuel control output signal to the fuel control actuator to control operations of the fuel control actuator, wherein the fuel controller determines the fuel control output signal based on the rotational speed error; a combustion air controller that provides a combustion air control output signal to the combustion air control actuator to control operations of the combustion air control actuator; and a cross channel controller in communication with the fuel controller and the combustion air controller, wherein the cross channel controller provides a combustion air control modification signal to the combustion air controller, and wherein the cross channel controller determines the combustion air control modification signal from the fuel control output signal using an air versus fuel model, and wherein the combustion air controller determines a preliminary combustion air control signal based on the exhaust temperature error, and further determines the combustion air control output signal based on both of the preliminary combustion air control signal and the combustion air control modification signal.