Method and unit for controlling a motor assembly

Abstract

The present invention relates to a method for controlling a motor assembly (100). The motor assembly (100) comprises at least a first electric machine (300) and a gas turbine engine (200). The gas turbine engine (200) comprises a low-pressure shaft (210) and a high-pressure shaft (220). The electric machine (300) is coupled to the low-pressure shaft (210), and the control method comprises a step, in which a mechanical work take-off is controlled to the first electric machine (300) for braking a rotation of the low-pressure shaft (210) in response to an activation of a thrust reverser (281) of the gas turbine engine (200) and / or to a disturbance of the airflow in a transverse plane at an air intake of the gas turbine engine (200). The invention also relates to a control unit (500) adapted to perform this method, a motor assembly (100) incorporating this control unit (100), the electric machine (300) and the gas turbine engine (200), and a computer program for carrying out this method.

Description

Description Title of the invention: Method and unit for controlling an assembly of motors Technical Field

[0001] The present invention relates to the technical field of aircraft engine assemblies, and more particularly to engine assemblies comprising at least one electric machine and one gas turbine engine with at least one high-pressure shaft and one low-pressure shaft. Previous technique

[0002] To increase the overall energy efficiency of transportation and reduce fuel consumption and greenhouse gas emissions, numerous hybrid powertrains have already been proposed, combining combustion engines and electric motors that contribute to overall efficiency beyond simply starting internal combustion engines. While these hybrid powertrains have most often been proposed for motor vehicles and incorporated piston engines, the hybridization of gas turbine engines, and more specifically aircraft gas turbine engines, has also been considered.

[0003] In the context of gas turbine engines, and particularly aircraft gas turbine engines, hybridization can offer advantages beyond energy efficiency. For example, in French patent application FR 3 094 043 A1, it was proposed to use an electric machine to extract mechanical work from the low-pressure shaft of a gas turbine engine, thereby braking it. This prevents instability in the low-pressure compressor, and specifically the risk of surge, which can be exacerbated, for instance, during gas turbine engine deceleration and / or changes in stator blade pitch. This avoids the need to open relief valves at the low-pressure compressor outlet, thus preventing a loss of energy efficiency.Other similar processes have been disclosed, for example, in the publications of patent applications US 2022 / 063824 A1 and US 2021 / 246837 A1. Description of the invention

[0004] The inventors have recognized other situations presenting a risk of instability in the low-pressure compressor of a gas turbine engine with a high-pressure shaft and a low-pressure shaft. This disclosure therefore aims to prevent, in these other risky situations, instability of the low-pressure compressor of such a gas turbine engine in an aircraft engine assembly comprising the gas turbine engine and at least one first electrical machine to which the low-pressure shaft of the gas turbine engine is mechanically coupled, without the need to open relief valves.

[0005] For this purpose, according to a first aspect of this disclosure, a method for controlling such an engine assembly may include a step in which a mechanical work take-off is commanded to the first electric machine to brake a rotation of the low-pressure shaft in response to an activation of a thrust reverser of the gas turbine engine and / or to a perturbation of the airflow in a transverse plane at the level of an air intake of the gas turbine engine.

[0006] Thanks to this extraction of mechanical energy, the stability margin of the low-pressure compressor can be effectively extended in response to these risky situations, despite the typically high inertia of the low-pressure shaft, more quickly than with relief valves and by recovering electrical energy that can be used or stored on board the aircraft.

[0007] Thus, the gas turbine engine can include a fan coupled to the low-pressure shaft to be driven in rotation by the low-pressure shaft. In this case, the fan could have variable-pitch blades, and the mechanical work taken up by the first electric machine could be controlled in conjunction with a change in the fan blade pitch, so as to also increase the work absorbed by the fan to better brake the low-pressure shaft. However, the application of this method is also conceivable with other types of gas turbine engines in which the low-pressure shaft is mechanically coupled in rotation to components with high rotating inertia, such as, for example, a turboprop engine in which the low-pressure shaft would be mechanically coupled in rotation to at least one pusher propeller, or a turboshaft engine in which the low-pressure shaft would be mechanically coupled in rotation to at least one lift rotor.

[0008] This process is also applicable to engine assemblies comprising a reducer connected to the low-pressure shaft for driving a mechanical component by the low-pressure shaft through the reducer, such as, for example, geared fan-driven turbojets as well as most turboprops and turbomotors.

[0009] This mechanical work can be controlled in an open loop. Thus, in its simplest form, the extraction of a predetermined amount of mechanical power can be controlled for a predetermined duration to extract the mechanical work. However, it is also possible for the extracted mechanical power and / or the duration of the extraction to be variable, depending, for example, on the position of the thrust reverser and / or a component of the airflow in a plane transverse to the air intake.

[0010] A second aspect of this disclosure relates to a control unit of the aforementioned motor assembly which can be adapted to command, at the first electric machine, a mechanical work tap to brake a rotation of the low-pressure shaft in response to an activation of a thrust reverser of the gas turbine engine and / or to a cross flow at the level of an air intake of the gas turbine engine.

[0011] A third aspect of this disclosure concerns a motor assembly comprising the control unit of the second aspect as well as the electric machine and the gas turbine motor.

[0012] A fourth aspect of this disclosure relates to a computer program that may include instructions which, when implemented by a control unit of the aforementioned motor assembly, cause the control unit to perform the control process of the first aspect. Brief description of the drawings

[0013] The purpose and advantages of this presentation will be better understood upon reading the detailed description below of embodiments given by way of non-limiting examples. This description refers to the attached figure pages, on which:

[0014] [Fig. 1] Figure 1 is a schematic representation of a motor assembly according to one embodiment, comprising a gas turbine engine, two electric machines and a control unit.

[0015] [Fig. 2] Figure 2 is a representation of an aircraft electrical network comprising two motor assemblies like that of Figure 1. Description of the implementation methods

[0016] As illustrated in Figure 1, a hybrid motor assembly 100 according to one embodiment may include a gas turbine motor 200, a first electric machine 300, a second electric machine 400 and a control unit 500. The gas turbine motor 200 may include a low-pressure shaft 210 and a high-pressure shaft 220. The low-pressure shaft 210 and the high-pressure shaft 220 may be arranged coaxially, as illustrated.The gas turbine engine 200 may also include a low-pressure compressor 230, a high-pressure compressor 240, a combustion chamber 250, a high-pressure turbine 260, and a low-pressure turbine 270, arranged successively in the direction of flow in an annular working fluid channel, such that air admitted upstream of the low-pressure compressor 230 is successively compressed in the low-pressure compressor 230 and in the high-pressure compressor 240, thereby generating hot combustion gases in the combustion chamber 250 by burning fuel injected into that combustion chamber. These combustion gases can then be successively expanded in the high-pressure turbine 260 and in the low-pressure turbine 270, so as to drive them into rotation.The high-pressure shaft 220 can be mechanically coupled to the high-pressure turbine 260 and the high-pressure compressor 240, so that the high-pressure turbine 260 can drive the high-pressure shaft 220 and the high-pressure compressor 240 in rotation, while the low-pressure shaft 210 can be mechanically coupled to the. low pressure turbine 270 and low pressure compressor 230, so that the low pressure turbine 270 can drive the low pressure shaft 210 and the low pressure compressor 230 in rotation.

[0017] As in the illustrated embodiment, the gas turbine engine 200 can be a turbofan engine also comprising a fan 280, which can also be mechanically coupled to the low-pressure shaft 230, so that it can also be driven in rotation by the low-pressure turbine 270 via the low-pressure shaft 210. As illustrated, the gas turbine engine 200 could also include a reduction gear 290 interposed between the low-pressure shaft 210 and the fan 280, so that the fan 280 can be driven at a lower rotational speed than the low-pressure shaft 210. However, a fan driven directly by the low-pressure shaft 210 is also conceivable. Furthermore, other architectures of the gas turbine engine 200, without a fan, are also possible.Thus, the gas turbine engine 200 could alternatively be a turboprop, with at least one pusher propeller mechanically coupled to the low-pressure shaft 210 through the reduction gear 290, or a turboshaft engine, with at least one lift rotor mechanically coupled to the low-pressure shaft 210 through the reduction gear 290. It is also conceivable, particularly for a turboshaft engine or a turboprop, that the gas turbine engine 200 comprises only a single compressor, mechanically coupled to the high-pressure shaft 210.

[0018] The gas turbine engine 200 may also include a thrust reverser 281, comprising valves and actuators for redirecting forward at least a portion of the air supplied by the fan 280, and one or more sensors 282 for detecting a disturbance in the airflow in a transverse plane at the air intake of the gas turbine engine 200. Such a disturbance, in a gas turbine engine 200 used to power an aircraft, may be caused by a crosswind and / or by vortex flow induced by the aircraft itself. These sensors 282 may be arranged, as illustrated, at the intake of the gas turbine engine 200, i.e., directly upstream of the fan 280, but alternatively or in addition to this arrangement, it would also be conceivable to have them located elsewhere. sensors 282, to use sensors located elsewhere outside the gas turbine engine 200, in particular to detect crosswinds, and / or sensors located inside the gas turbine engine 200 and adapted to detect instability resulting from a flow disturbance at the inlet. These sensors 282 may, in particular, be dynamic pressure sensors.

[0019] The first electric machine 300 can be configured, as illustrated, as a motor-generator to selectively convert electrical energy into mechanical work in motor mode and mechanical work into electrical energy in generator mode. This first electric machine 300 can be mechanically coupled to the low-pressure shaft 210 to drive the low-pressure shaft 210 in motor mode, and to be driven by the low-pressure shaft 210 in generator mode. However, it is also conceivable, within the scope of this disclosure, that it may be configured solely as an electric generator, capable only of converting mechanical work into electrical energy.

[0020] Similarly, the second electric machine 400 can also be configured, as illustrated, as a motor-generator to selectively convert electrical energy into mechanical work in motor mode and mechanical work into electrical energy in generator mode. This second electric machine can be mechanically coupled to the high-pressure shaft 220 to drive the high-pressure shaft 220 in motor mode, and to be driven by the high-pressure shaft 220 in generator mode. However, it is also conceivable, within the scope of this disclosure, that it may be configured solely as an electric motor, capable only of converting electrical energy into mechanical work.

[0021] As illustrated in Figure 2, in an aircraft 10, which may be an aircraft 10 with one or more similar engine sets 100, each of the first and second electric machines 300, 400 of each engine set 100 can be electrically connected to an electrical network 20. This electrical network 20 may be a direct current electrical network, and each of the first and second electric machines 300, 400 of each engine set 100 can then be electrically connected to the network electrical 20 through a corresponding converter 30. To supply this electrical network, the aircraft 10 may also include a fuel cell 50, an electrical storage device 60 (which may include, e.g., a battery and / or a supercapacitor) and / or an auxiliary generator set 40, which may include a generator 41 mechanically coupled to a combustion engine 42 for its operation and be electrically connected to the electrical network 20 through another converter 30.

[0022] The control unit 500 can be an electronic control unit, possibly a full authority digital engine control unit (FADEC). It can notably take the form of an electronic processor capable of implementing the instructions of a computer program to control the operation of the engine assembly 100. This control unit 500 can be connected to the gas turbine engine 200, in particular to receive data from the sensors 282 and / or to control the fuel supply to the combustion chamber 250, the position of the thrust reverser valves 281 and / or the timing of the various adjustable blades, as well as to each of the first and second electric machines 300, 400 to control the injection and / or extraction of mechanical work from the low-pressure shaft 210 and the high-pressure shaft 220, respectively.The control unit 500 can also be connected to a manual control, such as a throttle 80, and / or to a flight computer 90, in order to receive an operating instruction from the engine assembly 100, which can, for example, take the form of a thrust, power, or rotational speed instruction for the low-pressure shaft 210 and / or the high-pressure shaft 220. In the aircraft 10, the control unit 500 of each engine assembly 100 can also be connected to a control unit 70 of the electrical network 20, which can in turn be connected to each converter 30, the generator set 40, the fuel cell 50 and / or the electrical storage device 60, in order to maintain a balance in the electrical network 20.

[0023] The control unit 500 can be adapted to implement a control method for the engine assembly 100, in which, in response to the activation of the thrust reverser 281 and / or to a transverse flow detected through sensors 282 at the air intake of the gas turbine engine 200, the extraction of mechanical work W ei is controlled by the first electric machine 300 to brake the rotation of the low-pressure shaft 210. The mechanical work W eiThe power supplied by the first electric machine 300 can be controlled in open loop. In this case, both the power drawn by the first electric machine 300 during this supply and the duration of this supply can be predetermined or variable depending, for example, on a position setpoint of the thrust reverser and / or a transverse component of airflow at the inlet of the gas turbine engine 200. The power drawn can be constant during the supply duration or follow a predetermined profile.

[0024] In order to ensure the electrical supply of the first electric machine 300 during input while maintaining the balance of the electrical network 20, the control unit 500 can simultaneously control the withdrawal of mechanical work W eiby the first electric machine 300 on the low pressure shaft 210, the injection of a corresponding electrical energy by the second electric machine 400 into the high pressure shaft 220 and / or its storage in the electrical storage device 60.

[0025] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. A method for controlling an aircraft engine assembly (100) comprising at least a first electric machine (300) and a gas turbine engine (200) with a high-pressure shaft (220) and a low-pressure shaft (210) mechanically coupled to the first electric machine (300), the control method comprising a step in which a mechanical work withdrawal is commanded to the first electric machine (300) to brake a rotation of the low-pressure shaft (210) in response to an activation of a thrust reverser (281) of the gas turbine engine (200) and / or to a disturbance of the airflow in a transverse plane at an air intake of the gas turbine engine (200).

2. A control method according to claim 1, wherein the gas turbine engine (200) is a turbojet comprising a fan (280) coupled to the low-pressure shaft (210) to be driven in rotation by the low-pressure shaft (210).

3. A control method according to claim 2, wherein the blower (280) comprises variable pitch blades and the mechanical work removal by the first electric machine (300) is controlled jointly with a change in the pitch of the blower blades (280).

4. A control method according to any one of claims 1 to 3, further comprising a reducer (290) connected to the low-pressure shaft (210) for driving a mechanical element by the low-pressure shaft (210) through the reducer (290).

5. A control method according to any one of claims 1 to 4, wherein said mechanical work extraction is controlled in an open loop.

6. A control method according to any one of claims 1 to 5, comprising an additional step of consumption and / or storage of electrical energy generated by said mechanical work extraction.

7. Control unit (500) of an aircraft engine assembly (100) comprising at least a first electric machine (300) and a gas turbine engine (200) with a high-pressure shaft (220) and a low-pressure shaft (210) mechanically coupled to the first electric machine (300), the control unit (500) being characterized in that it is adapted to command the first electric machine (300) to take mechanical work to brake a rotation of the low-pressure shaft (210) in response to an activation of a thrust reverser (281) of the gas turbine engine (200) and / or to a disturbance of the airflow in a transverse plane at an air intake of the gas turbine engine (200).

8. Aircraft engine assembly (100) comprising the control unit (500) of claim 7 as well as the first electric machine (300) and the gas turbine engine (200).

9. A computer program comprising instructions which, when implemented by a control unit (500) of an aircraft engine assembly (100) comprising a first electric machine (300) and a gas turbine engine (200) with a high-pressure shaft (220) and a low-pressure shaft (210) mechanically coupled to the first electric machine (300), cause the control unit (500) to carry out the control method according to any one of claims 1 to 6.

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