Device and method for controlling the excursion of the speed of the high-pressure shaft of a turbomachine engine

Abstract

The invention relates to a method for controlling an aircraft turbomachine, the turbomachine comprising a high-pressure spool and a low-pressure spool, the method comprising the following steps: a)- detecting an acceleration request, said acceleration request generating an increase in a fuel setpoint in the turbomachine and an excursion of the speed of the high-pressure spool relative to the low-pressure spool, b)- comparing the speed of the high-pressure spool and a first predetermined threshold (S1), and if the speed of the high-pressure spool reaches the first threshold, diverting torque from the high-pressure spool, c)- if the speed of the high-pressure spool reaches a second predetermined threshold greater than the first threshold, reducing the fuel setpoint, and d)- continuing to divert torque from the high-pressure spool in order to return the speed of the high-pressure spool to below the second threshold.

Description

Description Title of the invention: DEVICE AND METHOD FOR CONTROLLING THE EXCURSION OF THE SPEED OF THE HIGH PRESSURE SHAFT OF A TURBOMACHINE ENGINE Technical Field

[0001] The present invention relates to a turbomachine for an aircraft, in particular, to the control of a turbomachine in order to control the excursion of the speed of the high pressure shaft of an engine of the turbomachine. Prior art

[0002] High bypass ratio (BPR) twin-spool turbomachines have a significant difference between the inertia of the low-pressure spool and the high-pressure spool. Consequently, the increase in fuel flow and potentially the electrical assistance by torque injection on the low-pressure shaft during the acceleration phase of the low-pressure regime to meet the pilot's needs lead to a sharp increase in the high-pressure regime, to the point of having an "excursion" of the high-pressure regime, due to the inertia difference between the high-pressure and low-pressure spools. This excursion of the high-pressure regime constrains from a cost and mass point of view the design of the mechanical parts of the high-pressure spool to ensure that the engine is kept within the declared and demonstrated operating limits.

[0003] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0004] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly and whose integration and use i in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0005] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0007] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft.

[0008] One of the objectives of the present invention is to make it possible to limit the excursion of the high pressure body speed and to advantageously allow the reduction of fuel consumption in the context of hybrid engines.

[0009] For this purpose, the present invention relates to a method for controlling an aircraft turbomachine, the turbomachine comprising a high pressure spool and a low pressure spool, the method comprising the following steps: a)- detecting an acceleration request, said acceleration request generating an increase in the fuel setpoint in the turbomachine and an excursion of the speed of said high pressure spool relative to the speed of said low pressure spool, b)- comparing the speed of said high pressure spool with a first predetermined threshold, and if the speed of said high pressure spool reaches the first threshold, taking torque from said high pressure spool, c)- if the speed of said high pressure spool reaches a second predetermined threshold higher than the first threshold, reducing said fuel setpoint, and d)- continuing to take torque from said high pressure spool,in order to bring the regime of said high pressure body back below said second threshold.,

[0010] Thus, it is possible to limit the high pressure body speed below a predetermined threshold while maintaining the requested trajectory to obey the demand acceleration, by modulating certain instructions and compensating for fuel instructions and torque instructions. This makes it possible in particular to limit the risks of damage to the turbomachine and in particular to the high-pressure body, caused by an excessive excursion in the high-pressure engine speed. Torque extraction can advantageously make it possible to reduce the high-pressure engine speed and avoid this excursion.

[0011] According to certain embodiments, the method is such that: e)- when the speed of said high pressure body falls below said second threshold, said fuel setpoint is stabilized and the sampling on said high pressure body is maintained, f)- when the speed of the low pressure body reaches a speed setpoint of said low pressure body, the torque modulation on said low pressure shaft is set to zero, g)- when the speed of said high pressure body falls below said first threshold, the torque modulation on said high pressure shaft is set to zero.

[0012] According to certain embodiments, during step b), at least part of the torque taken from said high pressure body is injected into said low pressure body in order to limit the fuel setpoint.

[0013] This advantageously makes it possible to reinject the torque power from the high pressure shaft onto the low pressure shaft and thus save fuel.

[0014] According to certain embodiments, the method comprises, during step d), an increase in torque on said low pressure shaft obtained from the extraction of torque from said high pressure shaft and the injection of at least a portion of this torque extracted from said low pressure shaft.

[0015] Thus, the mechanical power extracted from the high pressure shaft is advantageously reused, at least partially, to provide power to the low pressure shaft and thus limit the fuel required to maintain the speed of the low pressure shaft.

[0016] According to certain embodiments, during step d), the increase in torque on said low pressure shaft is determined to compensate for the fuel setpoint of step c).

[0017] According to certain embodiments, the values ​​of said first and second thresholds are dependent on a dimensioning of said high pressure shaft.

[0018] According to certain embodiments, the value of said first threshold is 5 to 6% lower than a maximum authorized value of said high pressure shaft speed and the value of said second threshold is 3 to 4% lower than said maximum authorized value of said high pressure shaft speed.

[0019] The invention also relates to a computer program comprising instructions for implementing a method according to the invention, when said computer program is executed by a computer.

[0020] The invention also relates to a computer-readable recording medium on which a computer program according to the invention is recorded.

[0021] The invention also relates to a device for controlling an aircraft turbomachine, the turbomachine comprising a high-pressure body and a low-pressure body, the device comprising one or more processors configured together or separately to: a)- detect an acceleration request, said acceleration request generating an increase in a fuel setpoint in the turbomachine and an excursion of the speed of said high-pressure body relative to said low-pressure body, b)- compare the speed of said high-pressure body with a first predetermined threshold, and if the speed of said high-pressure body reaches said first threshold, take torque from said high-pressure body, c)- if said speed of said high-pressure body reaches a second predetermined threshold higher than said first threshold, decrease said fuel setpoint, and d)- continue taking torque from said high-pressure body,in order to bring the regime of said high pressure body back below said second threshold.,

[0022] The invention also relates to an aircraft comprising a device according to the invention.

[0023] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the accompanying drawings which illustrate an exemplary embodiment thereof without any limiting character. Brief description of the drawings

[0024] [Fig. 1] Figure 1 is a schematic representation of a turbomachine according to an embodiment of the present invention.

[0025] [Fig. 2] Figure 2 is a schematic representation of a control system according to one embodiment of the invention.

[0026] [Fig. 3] Figure 3 is a representation of the evolution of the low pressure regime, the high pressure regime, the high pressure shaft torque, the low pressure shaft torque and the fuel according to an embodiment of the invention.

[0027] [Fig. 4] Figure 4 is a representation of a control method according to one embodiment of the invention.

[0028] [Fig. 5] Figure 5 is a schematic representation of an electronic control unit allowing the implementation of the control loops of Figure 2. Description of the embodiments

[0029] As illustrated in Figure 1, an aircraft engine assembly 100 according to one embodiment may include a turbomachine 200, a first electric motor 300 and a second electric motor 400, and a control unit 500. The turbomachine 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 turbomachine 200 may also comprise a low-pressure compressor 230, a high-pressure compressor 240, a combustion chamber 250, a high-pressure turbine 260, a low-pressure turbine 270, and an exhaust nozzle 275, arranged successively in the direction of flow in an annular vein of working fluid, so 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, to then generate hot combustion gases in the combustion chamber 250 by combustion of a fuel injected into this combustion chamber 250. These combustion gases can then be successively expanded in the high-pressure turbine 260 and in the low-pressure turbine 270, so as to actuate them in rotation, before escaping through the nozzle 275.The high pressure shaft 220 may be mechanically coupled to the high pressure turbine 260 and the high pressure compressor 240, such that the high pressure turbine 260 may rotate the high pressure shaft 220 and the high pressure compressor 240, while the low pressure shaft 210 may be mechanically coupled to the low pressure turbine 270 and the low pressure compressor 230, such that the low pressure turbine 270 may rotate the low pressure shaft 210 and the low pressure compressor 230.

[0030] As in the illustrated embodiment, the turbomachine 200 may be a bypass turbojet engine also comprising a fan 280, which may also be mechanically coupled to the low-pressure shaft 230, so as to also be able to be driven in rotation by the low-pressure turbine 270 through the low-pressure shaft 210. As illustrated, the turbomachine 200 could also comprise a reduction gear 290 interposed between the low-pressure shaft 210 and the fan 280, so that the fan 280 can be driven with a lower rotational speed than the low-pressure shaft 210. However, a fan with direct drive by the low-pressure shaft 210 is also conceivable. Furthermore, other architectures of the turbomachine 200, without a fan, are also conceivable.Thus, the turbomachine 200 could alternatively be a turboprop, with at least one propulsive 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, in particular for a turboshaft engine or a turboprop, that the turbomachine 200 comprises only a single compressor, mechanically coupled to the high pressure shaft 210.

[0031] The first electrical machine 300 may be, as illustrated, configured as a motor-generator to selectively transform electrical energy into mechanical work in motor mode and mechanical work into electrical energy in generator mode. This first electrical machine 300 may be mechanically coupled to the low-pressure shaft 210 to actuate, in motor mode, the low-pressure shaft 210, and to be actuated, in generator mode, by the low-pressure shaft 210. However, it is also conceivable, within the scope of the present invention, that it is configured only as an electrical generator, capable only of transforming mechanical work into electrical energy.

[0032] Similarly, the second electrical machine 400 may also be, as illustrated, configured as a motor-generator to selectively transform electrical energy into mechanical work in motor mode and mechanical work into electrical energy in generator mode. This motor may be mechanically coupled to the high-pressure shaft 220 to actuate, in motor mode, the high-pressure shaft 220, and to be actuated, in generator mode, by the high-pressure shaft 220. However, it is also conceivable, within the scope of the present invention, that it is not configured only as an electrical generator, capable only of transforming mechanical work into electrical energy.

[0033] The control unit 500 may be an electronic control unit, possibly a full authority digital engine control unit (FADEC). It may in particular take the form of an electronic processor capable of implementing the instructions of a computer program to control the operation of the engine assembly 200. This control unit 500 obtains signals representing operating parameters of the turbomachine 200. This control unit 500 may be connected to the turbomachine 200 to control in particular the supply of fuel to the combustion chamber 250, by providing it with a fuel setpoint WF_CMD, as well as to the engines 400 and 300 to provide them with a torque setpoint TRQ_CMD to control the injection and / or extraction of mechanical work respectively from the high pressure shaft 220 and the low pressure shaft 210.The control unit 500 can also be connected to a manual control, such as for example a throttle lever 80, and / or to a flight computer 90, in order to receive an operating instruction from the engine assembly 200, which can for example take the form of a thrust, power, or rotation speed instruction for the low pressure shaft 210 and / or the high pressure shaft 220.

[0034] The control unit 500 can also be connected to temperature sensors 276 and 277, arranged, respectively, directly downstream and upstream of the low pressure turbine 270, to receive temperatures of the combustion gases at the outlet of the low pressure turbine 270 and at the outlet of the high pressure turbine 260, to one or more pressure sensors (not shown), arranged in the combustion chamber 250 to sense a static pressure at the inlet of the combustion chamber 250 and transmit it to the control unit 500, and to one or more flow sensors (not shown), arranged in a circuit for supplying fuel to the combustion chamber 250.

[0035] Figure 2 is a schematic representation of a control system according to one embodiment of the invention.

[0036] This control system is preferably implemented in a control unit 500 as illustrated in FIG. 1, for example in a FADEC.

[0037] This system advantageously makes it possible to control the excursion of the high-pressure spool speed during acceleration of the low-pressure spool. In the present description, the term "excursion" of the high-pressure spool speed means the exceeding of the high-pressure spool speed beyond a high threshold linked to a maximum torque of the high-pressure shaft. This excursion may in particular be due to the inertia difference between the low-pressure spool and the high-pressure spool of the turbomachine. This inertia difference is particularly significant in the case of turbomachines with a high bypass ratio (also known as "By-Pass Ratio"). Consequently, the acceleration of the low-pressure spool, necessary to guarantee the required acceleration times, obeying a trajectory to limit the thrust asymmetry between the engines, may lead to an excursion of the high-pressure spool speed.

[0038] This system controls at least three commands: - the fuel instruction (WF32), - injection or extraction of power from the high pressure shaft via an electric machine or torque setpoint on the high pressure shaft (TRQHP), - injection or extraction of power from the low pressure shaft via an electric machine or torque setpoint on the low pressure shaft (TRQBP).

[0039] This system can also control or limit several output quantities, - The rotation speed of the high pressure (NH) shaft, - The rotation speed of the low pressure shaft (NL), - The pressure at the combustion chamber inlet (PS3) - The temperature at the low pressure turbine outlet (T5) - Exhaust gas temperature (EGT)

[0040] The control unit 500 is configured to implement a control method according to a particular embodiment of the invention and may comprise several functions for controlling the turbomachine. It may also receive as input and provide as output several control or setpoint signals, not mentioned in the context of the present invention.

[0041] The control unit 500 may include in particular a module 501 configured to control the torque of the low pressure engine shaft. This module receives as input a measurement of the speed of the low pressure shaft, RegimeBP, and a trajectory instruction, TrajBP, and provides as output a differential torque command ATRQBP. TraJBP and an AWF fuel differential setpoint TraJBP .

[0042] The control unit 500 may also include a second module 502 which determines a second AWF fuel differential control. seui1The module 502 receives as input a high pressure speed threshold value, S2, called the second threshold value, and a measurement of the high pressure shaft speed, RegimeHP.

[0043] The control unit 500 may also comprise a third module 503 configured to control the torque of the high pressure motor shaft in differential form ATRQHP Pre ' seui1 The module 503 receives as input a high pressure speed threshold value, SI, called the first threshold value, and the high pressure shaft speed measurement, RegimeHP.

[0044] A switch 504 controlled by an acceleration indicator signal TopAcc. The TopAcc signal, when activated, i.e. when acceleration is detected, allows the switch 504 to select, as the torque reference command on the low pressure shaft, the ATRQBP command TraJBP. This represents a differential, this differential is applied to the previous value to obtain the current torque setpoint value on the low pressure shaft TRQBP.

[0045] The value of the WF32 fuel control is obtained by selecting the minimum increment between an increment value determined by the module 501, AWF TraJBP , and an increment value determined by module 502, AWF 561 " 1 . This represents a differential, this differential is applied to the previous value to obtain the current fuel control value WF32.

[0046] A switch 505 selects as torque command on the high pressure shaft, the command the current value ATRQHP pre ' seui1when the high pressure motor shaft speed is higher than the first threshold, SI. This represents a differential, this differential is applied to the previous value to obtain the current torque setpoint value of the high pressure shaft TRQHP.

[0047] We will now describe figure 2 in relation to figure 3 which represents the changes in the speeds of the low pressure and high pressure engines, the fuel instructions WF32 and the torque instructions of the high pressure TRQHP and low pressure TRQBP shafts according to an embodiment of the invention.

[0048] When detecting an acceleration request, phase 1 of figure 3, the module 501 controls the torque of the low pressure shaft and the fuel setpoint WF32 as long as the speed of the high pressure shaft does not exceed a threshold SI.

[0049] As indicated previously, turbomachines with a high bypass ratio can have a significant difference in inertia between the low-pressure spool and the high-pressure spool and thus, during acceleration, the torque on the high-pressure shaft can quickly reach values ​​that could lead to degradation thereof. Thus, when the torque of the high-pressure shaft exceeds a first threshold SI, the module 503 controls the torque of the high-pressure spool by taking torque from the high-pressure shaft. Advantageously, the torque taken from the high-pressure shaft is reinjected, at least partially, onto the low-pressure shaft. This advantageously makes it possible to limit the fuel necessary to follow the acceleration trajectory by replacing the energy provided by the fuel with the mechanical energy provided by the torque of the high-pressure shaft.

[0050] Thus, the high-pressure torque is limited in its excursion, but continues to increase more slowly. This is illustrated by phase 2 of Figure 3.

[0051] When the high pressure shaft speed reaches a second threshold S2, higher than the first threshold SI, the module 502 controls the fuel setpoint WF32 instead of the module 501. This control consists of reducing the fuel setpoint so as to limit the excursion of the high pressure speed to the threshold S2, this is illustrated by phase 3 of figure 3.

[0052] Since the fuel setpoint is reduced to limit the excursion of the high-pressure shaft speed, the power taken from the high-pressure shaft torque is advantageously injected into the low-pressure shaft torque to avoid straying too far from the trajectory requested for the low-pressure speed. This advantageously allows fuel savings.

[0053] The torque injection on the low pressure shaft makes it possible to compensate for the reduction in fuel, to maintain the trajectory as close as possible, phase 4 of figure 3.

[0054] When the high pressure shaft speed falls below threshold S2, phase 5 of figure 3, module 501 resumes control of the fuel setpoint WF32 to stabilize it and maintains the sampling on the high pressure body, phase 5 of figure 4. When the low pressure body speed reaches a low pressure body speed setpoint, the torque modulation on the low pressure shaft is gradually set to zero.

[0055] When the high pressure body speed falls below the said first threshold, the modulation of the high pressure shaft torque is gradually set to zero, phase 6 of figure 3. The acceleration thrust is maintained by the fuel setpoint.

[0056] The SI and S2 thresholds are advantageously dependent on the dimensioning of the high pressure shaft and can, for example, be located, for SI, between 5 and 6% below the maximum speed value, and for S2, between 3 and 4% below the maximum speed value.

[0057] Figure 3 represents the phases or stages as observed for: - the high pressure body regime, - the low pressure body regime, - the torque on the high pressure shaft TRQHP, - the torque on the low pressure shaft TRQBP, - the WF32 fuel instruction.

[0058] The dotted curve represents the curves of the various quantities mentioned above by the implementation of an embodiment of the present invention and the solid line curves represent the curves without the implementation of the invention.

[0059] The different phases or stages are described with reference to Figure 2 and Figure 4.

[0060] Figure 4 represents a method implemented, for example by the control unit 500 and the different modules included in the module 500, described in Figure 2. The method described in Figure 4 can also be implemented by one or more processors, together or separately, present in the control unit 500. The method of Figure 4 can also be described using Figure 3 which represents the evolution of the speeds of the high pressure and low pressure engine as well as the torque of the high pressure shaft TRQHP, the torque of the low pressure shaft TRQBP and the fuel consumption WF32.

[0061] During an El step, the control unit detects whether an acceleration request is requested. This detection can be carried out by detecting the value of the TopAcc signal for example. This detection can take into account a hysteresis, so as to be robust with respect to oscillations.

[0062] This acceleration demand generates, or triggers, an increase in the speed of the high pressure body and the low pressure body as well as an increase in fuel consumption to satisfy this acceleration demand. As indicated previously, the difference in inertia between the low pressure body and the high pressure body can generate a speed excursion of the high pressure body to allow the low pressure body speed to follow this trajectory. This excursion would lead to significant mechanical and cost constraints in the design of the high pressure body to avoid deterioration at these high speeds. It is therefore proposed to limit this excursion while best satisfying the desired trajectory of the low pressure shaft speed to satisfy this acceleration demand.

[0063] The present invention therefore makes it possible to control this excursion in order in particular to ensure the following objectives: - The proper functioning of the engine (ensure aircraft samples, the richness of the air / fuel mixture in the combustion chamber, avoid extinction, particularly when ingesting water or hail), - Engine performance (acceleration time, deceleration time, pilot throttle) - Physical actuation limits (sizing of the fuel system, sizing of electrical machines) - Engine protection (prevent high pressure compressor surge, prevent overheating and low speed surge, prevent unscrewing, low limit overspeed and combustion chamber burst, start-up)

[0064] When the high-pressure body speed is higher than a first threshold SI, during step E2, torque is taken from the high-pressure body, step E3. Taking torque from the high-pressure body makes it possible to reduce the excursion of the high-pressure engine speed. The high-pressure speed curve in Figure 3 indicates a slowing of the excursion, phase 2.

[0065] In some embodiments, the torque draw from the high pressure body, or a portion of this draw, is injected into the low pressure body in order to limit the fuel setpoint WF32.

[0066] If the modulation of the torque on the high pressure shaft up to the maximum possible draw is not sufficient to maintain the high pressure speed at the threshold SI, then the speed of the high pressure body can reach a second threshold S2, during step E4. The fuel setpoint WF32 is then reduced, step E5, which is observed on the fuel curve during phase 3 of figure 3. The reduction of the fuel setpoint WF32 combined with the continuation of torque draw TRQHP on the shaft high pressure advantageously limits the excursion of the high pressure shaft below the S2 threshold.

[0067] In order to allow the low pressure shaft speed to follow the trajectory, power can be injected by increasing torque TRQBP, on the low pressure shaft, step E6.

[0068] In some embodiments, the increase in torque TRQBP on the low pressure shaft is obtained from taking torque TRQHP from the high pressure shaft and injecting at least a portion of this taken torque onto the low pressure shaft.

[0069] In some embodiments, the torque increase TRQBP on the low pressure shaft is determined to compensate for the fuel setpoint WF32 of step E6.

[0070] When the speed of the high pressure body returns below said second threshold S2, step E7, the fuel setpoint WF32 is stabilized, step E8, and the torque sampling TRQHP is maintained on the high pressure body, step E9.

[0071] When the low pressure body speed reaches a low pressure body speed setpoint, step E10, the low pressure shaft torque TRQBP is set to zero, step Eli. When the high pressure body speed falls below the first threshold SI, step E12, the high pressure shaft torque TRQHP is set to zero, step E13.

[0072] In one embodiment, the functional modules of Figure 2 correspond to the execution of a computer program by the control unit 500. An example of a control unit 500 is shown in Figure 5. The control unit 500 has the hardware architecture of a computer and notably comprises one or more processors 21 (only one being shown), a non-volatile memory 22, a volatile memory 23 and an interface 24. The processor 21 allows the execution of computer programs stored in the non-volatile memory 22, using the volatile memory 23. The interface 24 makes it possible to obtain measurement signals and to emit control signals.

[0073] The non-volatile memory 22 comprises in particular a computer program PI whose execution corresponds to the implementation of a control method in accordance with an embodiment of the invention, and for example that described with reference to FIG. 4. During the execution of the computer program PI, the interface 24 makes it possible to obtain measurement signals representing the regimes RegimeHP and RegimeBP, the signal TopAcc, the trajectory TrajBP and to emit the signals TRQBP, TRQHP, WF32. Alternatively, at least part of the functional modules of Figure 2 may correspond to hardware circuits, for example programmable logic circuits.

Claims

Claims

1. Method for controlling an aircraft turbomachine, the turbomachine comprising a high pressure body and a low pressure body, the method comprising the following steps: a)- detecting (El) an acceleration request, said acceleration request generating an increase in a fuel setpoint in the turbomachine and an excursion of the speed of said high pressure body relative to the speed of said low pressure body, b)- comparing the speed of said high pressure body with a first predetermined threshold (SI), and if the speed of said high pressure body reaches (E2) the first threshold (SI), taking (E3) torque from said high pressure body, c)- if the speed of said high pressure body reaches (E4) a second predetermined threshold (S2) higher than the first threshold (SI), decreasing (E5) said fuel setpoint, and d)- continuing to take torque from said high pressure body,in order to bring (E7) the speed of said high pressure body back below said second threshold (S2).

2. Method according to claim 1 such that: e)- when the speed of said high pressure body returns (E7) below said second threshold (S2), said fuel setpoint is stabilized (E8) and the sampling on said high pressure body is maintained (E9), f)- when the speed of the low pressure body reaches (E10) a speed setpoint of said low pressure body, the torque modulation on said low pressure shaft is set to zero (Eli), g)- when the speed of said high pressure body returns (E12) below said first threshold (SI), the torque modulation on said high pressure shaft is set to zero (E13).,

3. Method according to one of claims 1 or 2 wherein during step b), at least part of the torque taken from said high pressure body is injected into said low pressure body in order to limit the fuel setpoint.

4. Method according to one of claims 1 to 3 comprising during step d), an increase in torque on said low pressure shaft obtained from the taking of torque on said high pressure shaft and the injection of at least part of this torque taken on said low pressure shaft.

5. Method according to claim 4 wherein during step d), the increase in torque on said low pressure shaft is determined to compensate for the fuel setpoint of step c).

6. Method according to one of the preceding claims, according to which the values ​​of said first and second thresholds are dependent on a dimensioning of said high pressure shaft.

7. A computer program comprising instructions for implementing a method according to any one of claims 1 to 6, when said computer program is executed by a computer.

8. A computer-readable recording medium having a computer program recorded thereon according to claim 7.

9. Device for controlling an aircraft turbomachine, the turbomachine comprising a high-pressure body and a low-pressure body, the device comprising one or more processors configured together or separately to: a)- detect (El) an acceleration request, said acceleration request generating an increase in a fuel setpoint in the turbomachine and an excursion of the speed of said high-pressure body relative to said low-pressure body, b)- compare said speed of the high-pressure body with a first predetermined threshold (SI), and if the speed of said high-pressure body reaches (E2) said first threshold (SI), take (E3) torque from said high-pressure body, c)- if said speed of said high-pressure body reaches (E4) a second predetermined threshold (S2) higher than the first threshold (SI), decrease (E5) said fuel setpoint, and d)- continue taking torque from said high-pressure body,in order to bring (E7) the regime of said high pressure body back below said second threshold (S2).,

10. Aircraft comprising a device according to claim 9.

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