Device and method for controlling an auxiliary engine suitable for supplying thrust power to the rotor of a helicopter

Patent metadata

Field	Value
Publication number	US-9919806-B2
Application number	US-201615533986-A
Country	US
Kind code	B2
Filing date	Jan 11, 2016
Priority date	Jan 12, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

The invention relates to a device for controlling an auxiliary engine ( 8 ) comprising a gas generator and a free turbine suitable for being able to be connected mechanically to the rotor ( 12 ) of a helicopter in order to supply it with thrust power, characterised in that said control device comprises a proportional-integral controller ( 30 ) having a proportional gain (Kp) and an integral gain (Ki), which are dependent on the rotation speed of said gas generator, said controller ( 30 ) being configured to receive an error signal representing a speed error of said free turbine, and to generate a signal (Sc) for correcting the drive speed of said gas generator obtained by adding a signal proportional to said error signal in accordance with said proportional gain (Kp), and an integrated signal (Si) resulting from the addition of a signal proportional to said error signal in accordance with said integral gain (Ki) and a memory signal (Sm), supplied by a feedback loop ( 31 ) of said integrated signal (Si), said memory signal (Sm) being dependent on a measurement representing the rotation speed of said free turbine.

First claim

The invention claimed is:

1. A device for controlling an auxiliary engine comprising a gas generator and a free turbine suitable for being able to be connected mechanically to the rotor of a helicopter in order to supply it with thrust power in addition to thrust power supplied by the main engines,
wherein said control device comprises a proportional-integral controller having a proportional gain and an integral gain, which are dependent on the rotation speed of said gas generator of said auxiliary engine of the helicopter, said controller being configured to receive a signal representing a speed error of said free turbine of said auxiliary engine referred to as an error signal, and to generate a signal for correcting the drive speed of said gas generator of said auxiliary engine, said correction signal being obtained by adding a signal proportional to said error signal in accordance with said proportional gain, and a signal, referred to as an integrated signal, resulting from the addition of a signal proportional to said error signal in accordance with said integral gain and a signal, referred to as a memory signal, supplied by a feedback loop of said integrated signal, said memory signal being dependent on a measurement representing the rotation speed of said free turbine of said auxiliary engine.

2. The control device according to claim 1 , wherein said feedback loop comprises:
a first circuit configured to supply a memory signal that is an image of said integrated signal,
a second circuit configured to supply a memory signal proportional to said integrated signal in accordance with a gain, referred to as a cancellation gain, of less than 1,
a selector configured to select said first circuit or said second circuit according to the results of a test on a measurement representing the rotation speed of said free turbine of said auxiliary engine.

3. The control device according to claim 2 , wherein said test performed by said selector consists in comparing said error signal with a predetermined droop threshold so as to be able to activate said first circuit if the speed error, in absolute value, is higher than said predetermined droop threshold and to activate said second circuit if the speed error, in absolute value, is lower than said threshold, such that said integrated signal is gradually cancelled.

4. The control device according to claim 2 , wherein said cancellation gain of said second circuit is dependent on the speed error of said free turbine of said auxiliary engine.

5. The control device according to claim 1 ,
wherein it further comprises an adder configured to add said correction signal generated by said proportional-integral controller and a signal corresponding to a target operating point of said auxiliary engine that depends on said flight conditions of the helicopter, to supply a setpoint signal to said gas generator of said auxiliary engine.

6. An architecture of a multi-engine helicopter comprising a thrust power unit comprising main engines suitable for being connected to a power transmission box driving a rotor of the helicopter, and an auxiliary engine comprising a gas generator and a free turbine, said auxiliary engine being suitable for being able to be connected firstly to an on-board system the helicopter in order to be able to supply said on-board system with electrical energy on the ground, and secondly to said thrust power unit in order to be able to supply extra thrust power during a flight of the helicopter, wherein said architecture further comprises a device for controlling said auxiliary engine according to claim 1 , so as to be able to adapt, during a flight of the helicopter, the thrust power supplied by said auxiliary engine to said thrust power unit, independently of any balancing between said main engines and the auxiliary engine.

7. A helicopter comprising an architecture according to claim 6 .

8. A method for controlling an auxiliary engine comprising a gas generator and a free turbine suitable for supplying thrust power to a helicopter rotor, wherein it comprises the following steps:
receiving a signal representing a speed error of said free turbine of said auxiliary engine, referred to as an error signal,
generating a signal for correcting the drive speed of said gas generator of said auxiliary engine resulting from the addition of a signal proportional to said error signal in accordance with a proportional gain, and a signal, referred to as an integrated signal, resulting from the addition of a signal proportional to said error signal in accordance with an integral gain and a signal, referred as a memory signal, dependent on a measurement representing the rotation speed of said free turbine of said auxiliary engine.

9. The method according to claim 8 , wherein said memory signal is a signal obtained by a selection between a signal that is an image of said integrated signal and a signal proportional to said integrated signal in accordance with a gain, referred to as a cancellation gain, of less than 1, the selection being dependent on the results of a test on a measurement representing the rotation speed of said free turbine of said auxiliary engine.

10. The method according to claim 9 , wherein said selection test consists in comparing said error signal with a predetermined droop threshold and choosing said signal that is an image of the integrated signal if the speed error, in absolute value, is higher than said predetermined droop threshold and choosing said signal proportional to said integrated signal in accordance with said cancellation gain if the speed error, in absolute value, is lower than said threshold.

Assignees

• Safran Helicopter Engines

Inventors

• Marin Jean Philippe Jacques
• Gallot Matthieu
• Etchepare Philippe

Classifications

• B64D35/08

  characterised by the transmission being driven by a plurality of power plants (for hybrid-electric power plants B64D35/022) · CPC title

• F05D2220/50

  for auxiliary power units (APU's) · CPC title

• F02C6/02

  Plural gas-turbine plants having a common power output · CPC title

• F05D2270/304

  Spool rotational speed · CPC title

• F02C3/04

  having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) · CPC title