# US 10,480,421 B2 · System and method for an engine controller based on acceleration power

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,480,421 B2
- Document ID: US10480421B2
- Status: Granted
- Kind: B2
- Application number: 15/361,251
- Filed: 2016-11-25
- Published: 2018-02-08
- Granted: 2019-11-19
- Earliest claimed: 2016-08-04
- Assignees: Pratt & Whitney Canada Corp.
- Applicants: Pratt & Whitney Canada Corp.
- Inventors: Gabriel Meunier; Alexandre Charest; Sylvain Lamarre
- Web page: https://patentgrep.com/patent/US10480421B2

## CPC

- F02C 9/263: {by means of fuel metering valves}
- F01D 21/003: {Arrangements for testing or measuring (for measuring vibrations G01H)}
- F05D 2220/32: in gas turbines
- F05D 2270/04: to control acceleration (u)
- F05D 2270/304: Spool rotational speed
- F05D 2270/306: Mass flow
- F05D 2270/54: by electronic means, e.g. electronic tubes, transistors or IC's within an electronic circuit
- F05D 2270/708: with comparison tables
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

The system of claim 1, wherein determining the required fuel flow comprises applying the equation:
K(ΔWf)=PAccel,
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;
PAccel 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.

### Claim 7 (depends on 1)

The system of claim 1, wherein determining the required fuel flow comprises applying the equation:
K(Wftot−Wfss)=JggNg{dot over (N)}gKunits,
wherein:
Wftot represents a total fuel flow;
Jgg represents the shaft inertia of the engine;
Ng represents a current gas generator speed;
Wfss represents the steady state fuel flow for Ng;
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow; and
Kunits represents a coefficient accounting for unit conversions.

### Claim 8 (depends on 1)

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:
WfFF represents the output of the feedforward controller;
Wfss represents the steady state fuel flow for the requested engine speed;
Jgg represents the shaft inertia of the engine;
Ngreq 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
Kunits represents a coefficient accounting for unit conversions.

### Claim 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.

### Claim 10 (depends on 9)

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

### Claim 11 (depends on 9)

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

### Claim 12 (depends on 11)

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.

### Claim 13 (depends on 9)

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

### Claim 14 (depends on 9)

The method of claim 9, wherein determining the required fuel flow comprises applying the equation:
K(ΔWf)=PAccel,
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;
PAccel 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.

### Claim 15 (depends on 9)

The method of claim 9, wherein determining the required fuel flow comprises applying the equation:
K(Wftot−Wfss)=JggNg{dot over (N)}gKunits,
wherein:
Wftot represents a total fuel flow;
Jgg represents the shaft inertia of the engine;
Ng represents a current gas generator speed;
Wfss represents the steady state fuel flow for Ng;
K is a linear coefficient representing the relationship between fuel flow and acceleration power generated by the fuel flow; and
Kunits represents a coefficient accounting for unit conversions.

### Claim 16 (depends on 9)

The method of claim 9, 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:
WfFF represents the output of the feedforward controller;
Wfss represents the steady state fuel flow for the requested engine speed;
Jgg represents the shaft inertia of the engine;
Ngreq 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
Kunits represents a coefficient accounting for unit conversions.

### Claim 17

A non-transitory computer-readable medium having stored thereon program code executable by a processor for controlling a gas turbine engine, the program code comprising instructions 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;
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.

### Claim 18 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the program code further comprises instructions for limiting acceleration of the gas turbine engine by applying a rate limit to the requested engine speed.

### Claim 19 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the program code further comprises instructions for adjusting the required fuel flow based on an acceleration error.

### Claim 20 (depends on 17)

The non-transitory computer-readable medium of claim 17, 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:
WfFF represents the output of the feedforward controller;
Wfss represents the steady state fuel flow for the requested engine speed;
Jgg represents the shaft inertia of the engine;
Ngreq 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
Kunits represents a coefficient accounting for unit conversions.