System and method for an engine controller based on acceleration power

Patent metadata

Field	Value
Publication number	US-10480421-B2
Application number	US-201615361251-A
Country	US
Kind code	B2
Filing date	Nov 25, 2016
Priority date	Aug 4, 2016
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Systems and methods for controlling an gas turbine engine are provided. The method comprises receiving a requested engine speed and obtaining a shaft inertia of the engine, a steady state fuel flow for the requested engine speed, and a relationship between fuel flow and acceleration power generated by the fuel flow. A required fuel flow to obtain an engine acceleration is determined as a function of the requested engine speed, the shaft inertia of the engine, the steady state fuel flow for the requested engine speed, and the relationship between fuel flow and acceleration power generated by the fuel flow. A command to a fuel flow metering valve is output in accordance with the required fuel flow.

First claim

The invention claimed is:

1. A system for controlling a gas turbine engine, the system comprising:
an interface to a fuel flow metering valve for controlling a 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 comprising a feedforward controller configured for:
receiving a requested engine speed;
obtaining a shaft inertia of the engine, a steady state fuel flow for the requested engine speed, and a relationship between fuel flow and acceleration power generated by the fuel flow; and
determining the required fuel flow to obtain an engine acceleration as a function of the requested engine speed, the shaft inertia of the engine, the steady state fuel flow for the requested engine speed, and the relationship between fuel flow and acceleration power generated by the fuel flow.

2. The system of claim 1 , wherein the controller is further configured to limit acceleration of the gas turbine engine by applying a rate limit to the requested engine speed.

3. The system of claim 1 , wherein the controller comprises a feedback controller configured to adjust the required fuel flow based on an acceleration error.

4. The system of claim 3 , wherein the acceleration error is determined based on a reference acceleration and an actual engine acceleration determined from an actual gas generator speed.

5. The system of claim 1 , wherein the feedforward controller is configured to obtain the steady state fuel flow for the requested engine speed from a look-up table.

6. The system of claim 1 , wherein determining the required fuel flow comprises applying the equation:
K (Δ Wf )= P Accel ,

wherein:
ΔWf represents additional fuel flow to be added to a current fuel flow for operating in a steady-state at the requested engine speed;
P Accel represents acceleration power of the engine generated from the additional fuel flow; and
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow.

7. The system of claim 1 , wherein determining the required fuel flow comprises applying the equation:
K ( Wf tot −Wf ss )= J gg N g {dot over (N)} g K units ,
wherein:
Wf tot represents a total fuel flow;
J gg represents the shaft inertia of the engine;
N g represents a current gas generator speed;
Wf ss represents the steady state fuel flow for N g ;
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow; and
K units represents a coefficient accounting for unit conversions.

8. The system of claim 1 , wherein determining the required fuel flow comprises applying the equation:

Wf
FF

=

J
gg

⁢

Ng
req

⁢

N
.

⁢

g
req

⁢

K
units

K

+

Wf
SS

,

wherein:
Wf FF represents the output of the feedforward controller;
Wf ss represents the steady state fuel flow for the requested engine speed;
J gg represents the shaft inertia of the engine;
Ng req represents the requested engine speed;
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow; and
K units represents a coefficient accounting for unit conversions.

9. A method for controlling a gas turbine engine, the method comprising:
receiving a requested engine speed;
obtaining a shaft inertia of the engine, a steady state fuel flow for the requested engine speed, and a relationship between fuel flow and acceleration power generated by the fuel flow;
determining a required fuel flow to obtain an engine acceleration as a function of the requested engine speed, the shaft inertia of the engine, the steady state fuel flow for the requested engine speed, and the relationship between fuel flow and acceleration power generated by the fuel flow; and
outputting a command to a fuel flow metering valve in accordance with the required fuel flow.

10. The method of claim 9 , further comprising limiting acceleration of the gas turbine engine by applying a rate limit to the requested engine speed.

11. The method of claim 9 , further comprising adjusting the required fuel flow based on an acceleration error.

12. The method of claim 11 , wherein the acceleration error is determined based on a reference acceleration and an actual engine acceleration determined from an actual gas generator speed.

13. The method of claim 9 , wherein the steady state fuel flow for the requested engine speed is obtained from a look-up table.

14. The method of claim 9 , wherein determining the required fuel flow comprises applying the equation:
K (Δ Wf )= P Accel ,

wherein:
ΔWf represents additional fuel flow to be added to a current fuel flow for operating in a steady-state at the requested engine speed;
P Accel represents acceleration power of the engine generated from the additional fuel flow; and
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow.

15. The method of claim 9 , wherein determining the required fuel flow comprises applying the equation:
K ( Wf tot −Wf ss )= J gg N g {dot over (N)} g K units ,
wherein:
Wf tot represents a total fuel flow;
J gg represents the shaft inertia of the engine;
N g represents a current gas generator speed;
Wf ss represents the steady state fuel flow for N g ;
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow; and
K units represents a coefficient accounting for unit conversions.

16. The method of claim 9 , wherein determining the required fuel flow comprises applying the equation:

Wf
FF

=

J
gg

⁢

Ng
req

⁢

N
.

⁢

Assignees

• Pratt & Whitney Canada

Inventors

• Meunier Gabriel
• Charest Alexandre
• Lamarre Sylvain

Classifications

• F05D2270/04

  to control acceleration (u) · CPC title

• F05D2270/304

  Spool rotational speed · CPC title

• F05D2270/708

  with comparison tables · CPC title

• F02C9/263 Primary

  by means of fuel metering valves · CPC title

• F05D2220/32

  in gas turbines · CPC title