Control system and method for controlling a gas turbine engine during transients

Patent metadata

Field	Value
Publication number	US-9850823-B2
Application number	US-201314140606-A
Country	US
Kind code	B2
Filing date	Dec 26, 2013
Priority date	Dec 26, 2013
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A control system and method for a gas turbine engine are provided A controller ( 40 ) is responsive to at least one parameter to control an air-to-fuel ratio. The parameter may be a measured engine exhaust temperature from a temperature sensor ( 42 ). During a transient, such as a ramping condition of the engine, a measured value of such parameter may have a time lag affecting one or more control settings during the transient condition. The controller is programmed to predictively determine a bias for the measured value of the parameter to correct such control settings and avoid combustion instabilities and high emissions during such transient conditions.

First claim

The invention claimed is:

1. A control system for a gas turbine engine comprising:
a controller responsive to at least one parameter to control an air-to-fuel ratio, wherein during a transient condition of the engine, a measured value of said at least one parameter comprises a time lag affecting at least one control setting during the transient condition of the engine, wherein the controller is programmed to predictively determine a bias to correct said at least one control setting;
wherein a determination of the bias is based at least in part on a ramp rate of the engine during the transient condition;
wherein said controller provides control that in part is based on engine exhaust temperature measurements and said at least one parameter comprises a measured engine exhaust temperature;
wherein a determination of the bias is based on the time lag determined by the difference between the idealized engine exhaust temperature response and the measured engine exhaust temperature; and
further comprising inlet guide vanes to control inlet air flow to a compressor, wherein said at least one control setting comprises a control setting to position said inlet guide vanes during the transient condition of the engine.

2. The control system of claim 1 , wherein the time lag is based on comparing the measured engine exhaust temperature to an idealized engine exhaust temperature response.

3. The control system of claim 1 , wherein the bias is applied to a steady-state exhaust temperature value at a present engine condition.

4. The control system of claim 1 , wherein a determination of the bias is based on the following equation:
Texh bias,1 =a ×( MW rate ×Δt lag ×( Texh SS,1 −Texh SS,2 ))+ b

where,
Texh bias,l =bias to a steady-state exhaust temperature (Texh) value at a present engine condition,
Texh SS,1 =the steady-state Texh value at the present engine condition,
Texh SS,2 =a steady-state Texh value at a target engine condition,
MW rate =ramp rate of the engine,
Δt lag =value of the lag time,
a =a proportionality factor, and
b =a site-specific constant.

5. The control system of claim 1 , further comprising a fuel system to control at least one fuel flow to a combustor, wherein said at least one control setting further comprises a demand for said at least one fuel flow.

6. The control system of claim 1 , further comprising a bias adjustor configured to adjust the bias as a function of ambient temperature.

7. The control system of claim 1 , further comprising a bias adjustor configured to adjust the bias as a function of engine load.

8. The control system of claim 1 , further comprising a bias adjustor configured to adjust the bias as a function of ambient temperature and/or engine load.

9. A method for controlling a gas turbine engine, the method comprising:
controlling an air-to-fuel ratio with a controller responsive to at least one parameter;
measuring a value of said at least one parameter, which during a transient condition of the engine comprises a time lag affecting at least one control setting during the transient condition of the engine; and
predictively determining a bias to correct said at least one control setting; wherein the determining of the bias is based at least in part on a ramp rate of the engine during the transient condition;
wherein said controlling comprises controlling that in part is based on engine exhaust temperature measurements and said at least one parameter comprises a measured engine exhaust temperature;
wherein the determining of the bias is based on the time lag determined by the difference between the idealized engine exhaust temperature response and the measured engine exhaust temperature; and
further comprising controlling inlet air flow to a compressor with inlet guide vanes, wherein said at least one control setting comprises a control setting to position said inlet guide vanes during the transient condition of the engine.

10. The method of claim 9 , wherein the time lag is based on comparing the measured engine exhaust temperature to an idealized engine exhaust temperature response.

11. The method of claim 9 , further comprising applying the bias to a steady-state exhaust temperature value at a present engine condition.

12. The method of claim 9 , wherein the determining of the bias is based on the following equation:
Texh bias,1 =a ×( MW rate ×Δt lag ×( Texh SS,1 −Texh SS,2 ))+ b

where,
Texh bais,1 =bias to a steady-state exhaust temperature (Texh) value at a present engine condition,
Texh SS,1 =the steady-state Texh value at the present engine condition,
Texh SS,2 =a steady-state Texh value at a target engine condition,
MW rate =ramp rate of the engine,
Δt tag =value of the lag time,
a =a proportionality factor, and
b =a site-specific constant.

13. The method of claim 9 , further comprising controlling at least one fuel flow to a combustor, wherein said at least one control setting further comprises a demand for said at least one fuel flow.

14. The method of claim 9 , adjusting the bias as a function of ambient temperature.

15. The method of claim 9 , adjusting the bias as a function of engine load.

Assignees

• Miduturi Krishna C
• Kozachuk Danny W
• Siemens Ag

Inventors

• Miduturi Krishna C
• Kozachuk Danny W

Classifications

• F02C9/28

  Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence) · CPC title

• F02D41/30

  Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)} · CPC title

• F02C9/54 Primary

  by throttling the working fluid, by adjusting vanes · CPC title

• F05D2270/303

  Temperature · CPC title

• F05D2270/04

  to control acceleration (u) · CPC title