CA-2972727-C - SYSTEM AND METHOD FOR CONTROL OF GAS TURBINE ENGINE

Abstract

Systems and methods for regulating fuel flow to a gas turbine engine are provided. Power for the engine is governed using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting a fuel flow command. The shaft horsepower is determined from a torque measurement of the engine using a torque pressure transducer. When a momentary loss of the torque measurement from the torque pressure transducer is detected, power fluctuations due to the loss of torque measurement are limited by maintaining the feedback command from the feedback controller constant during the momentary loss of torque measurement.

Inventors

• Gabriel Meunier

Assignees

• PRATT & WHITNEY CANADA CORP.

Dates

Publication Date

20260505

Application Date

20170706

Priority Date

20161202

Claims (20)

1. CLAIMS 1. A method of regulating fuel flow to a gas turbine engine, the method comprising: governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting a fuel flow command; determining the shaft horsepower from a torque measurement of the engine using a torque pressure transducer; detecting a momentary loss of the torque measurement from the torque pressure transducer; and limiting power fluctuations due to the momentary loss of the torque measurement by maintaining the feedback command from the feedback controller constant during the momentary loss of the torque measurement.
2. 2. The method of claim 1, wherein detecting the momentary loss of the torque measurement comprises detecting a drop in a gearbox oil pressure of the engine.
3. 3. The method of claim 1, wherein detecting the momentary loss of the torque measurement comprises detecting a negative rate of change of the torque measurement.
4. 4. The method of any one of claims 1 to 3, wherein the outer control loop receives a power lever signal as input and uses the power level signal to define a reference shaft horsepower.
5. 5. The method of claim 4, wherein the reference shaft horsepower is determined based on at least one multi-dimensional lookup table.
6. 6. The method of claims 4 or 5, wherein the reference shaft horsepower is used to define a reference steady-state gas generator speed. Date re~ue/Date received 2024-01-17
7. 7. The method of claim 6, wherein the reference steady-state gas generator speed is used to anticipate a required gas generator speed in order to provide power to the engine.
8. 8. The method of claim 7, wherein the gas generator speed error is obtained by removing a measured gas generator speed from the required gas generator speed.
9. 9. The method of any one of claims 1 to 8, wherein determining the shaft horsepower comprises filtering a product of the torque measurement and an output shaft speed.
10. 10. A system for regulating fuel flow to a gas turbine engine, the system comprising: an interface to a fuel flow metering valve for controlling the fuel flow to the engine in response to a fuel flow command; and a controller connected to the interface and configured for outputting the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow, the controller configured for: governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting the fuel flow command; determining the shaft horsepower from a torque measurement of the engine using a torque pressure transducer; detecting a momentary loss of the torque measurement from the torque pressure transducer; and limiting power fluctuations due to the momentary loss of the torque measurement by maintaining the feedback command from the feedback controller constant during the momentary loss of the torque measurement. Date re~ue/Date received 2024-01-17
11. 11. The system of claim 10, wherein detecting the momentary loss of the torque measurement comprises detecting a drop in a gearbox oil pressure of the engine.
12. 12. The system of claim 10, wherein detecting the momentary loss of the torque measurement comprises detecting a negative rate of change of the torque measurement.
13. 13. The system of any one of claims 10 to 12, wherein the outer control loop receives a power lever signal as input and uses the power level signal to define a reference shaft horsepower.
14. 14. The system of claim 13, wherein the reference shaft horsepower is determined based on at least one multi-dimensional lookup table.
15. 15. The system of claims 13 or 14, wherein the reference shaft horsepower is used to define a reference steady-state gas generator speed.
16. 16. The system of claim 15, wherein the reference steady-state gas generator speed is used to anticipate a required gas generator speed in order to provide power to the engine.
17. 17. The system of claim 16, wherein the gas generator speed error is obtained by removing a measured gas generator speed from the required gas generator speed.
18. 18. The system of any one of claims 10 to 17, wherein determining the shaft horsepower comprises filtering a product of the torque measurement and an output shaft speed.
19. 19. A gas turbine engine controller for regulating fuel flow, the controller comprising: means for governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting a fuel flow command; Date re~ue/Date received 2024-01-17 means for determining the shaft horsepower from a torque measurement of the engine using a torque pressure transducer; means for detecting a momentary loss of the torque measurement from the torque pressure transducer; and means for limiting power fluctuations due to the momentary loss of the torque measurement by maintaining the feedback command from the feedback controller constant during the momentary loss of the torque measurement.
20. 20. The gas turbine engine controller of claim 19, wherein the means for detecting the momentary loss of the torque measurement comprises one of means for detecting a drop in a gearbox oil pressure of the engine and means for detecting a negative rate of change of the torque measurement. Date re~ue/Date received 2024-01-17

Description

05002993-2014CA SYSTEM AND METHOD FOR CONTROL OF GAS TURBINE ENGINE TECHNICAL FIELD This disclosure relates generally to the operation of gas turbine engines and, more particularly, to systems and methods for control of the supply of fuel provided to gas 5 turbine engines using electronic engine control systems. BACKGROUND The power available from a gas turbine engine is controlled through fuel flow regulation. When power governing is achieved using a torque pressure-transducer, there is a risk of experiencing momentary loss of the torque signal. This loss of 10 signal can be caused by, but is not limited to, a low-g aircraft condition. The loss of torque signal may cause power fluctuations and result in thrust disturbance at the aircraft level. There is a need to counter and/or minimize this effect. SUMMARY In accordance with a first broad aspect, there is provided a method of regulating fuel 15 flow to a gas turbine engine. The method comprises governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas 20 generator speed error used by the inner control loop for outputting a fuel flow command. The shaft horsepower is determined from a torque measurement of the engir:ie using a torque pressure transducer. When a momentary loss of the torque measurement from the torque pressure transducer is detected, power fluctuations due to the loss of torque measurement are limited by maintaining the feedback 25 command from the feedback controller constant during the momentary loss of torque measurement. In accordance with another broad aspect, there is provided a system for regulating fuel flow to a gas turbine engine. The system comprises an interface to a fuel flow metering valve for controlling the fuel flow to the engine in response to a fuel flow 30 command and a controller connected to the interface and configured for outputting - 1 05002993-2014CA the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow. The controller is configured for governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command 5 based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting a fuel flow command. The controller is configured for determining the shaft horsepower from a torque measurement of the engine using a torque pressure transducer. When a 10 momentary loss of the torque measurement from the torque pressure transducer is detected, power fluctuations due to the loss of torque measurement are limited by maintaining the feedback command from the feedback controller constant during the momentary loss of torque measurement. In accordance with yet another broad aspect, there is provided a gas turbine engine 15 controller for regulating fuel flow. The controller comprises means for governing power for the engine using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed 20 error, the gas generator speed error used by the inner control loop for outputting a fuel flow command, means for determining the shaft horsepower from a torque measurement of the engine using a torque pressure transducer, means for detecting a momentary loss of the torque measurement from the torque pressure transducer, and means for limiting power fluctuations due to the loss of torque measurement by 25 maintaining the feedback command from the feedback controller constant during the momentary loss of torque measurement In a further aspect, there is provided a non-transitory computer-readable storage medium having stored thereon computer-executable instructions that, when executed by at least one processor, cause the at least one processor to perform the 30 methods as described herein. DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying figures in which: 05002993-2014CA FIG. 1 is a schematic diagram of an example engine having a system for controlling a fuel supply; FIG. 2 is schematic diagram of an example differential oil pressure transducer; FIG. 3 is a schematic diagram of an example system for controlling a fuel supply for 5 an aircraft-mounted turbine engine; FIG. 4 is a simplified block diagram of an example system for controlling a fuel supply for an aircraft-mounted turbine engine; FIG. 5 i