Method for controlling a hybridized turbine engine

Abstract

One aspect of the invention relates to a method for controlling an aircraft turbine engine hybridized on a low-pressure spool, comprising: - acquiring a low-pressure speed setpoint (N1C) and a current low-pressure speed value (N1), - determining (21) that a low-pressure electrical hybridization (GIDL) activation must take place when: o The low-pressure speed setpoint (N1C) is below a thrust threshold, o A difference between the low-pressure speed setpoint (N1C) of the turbine engine (11) and the current low-pressure speed value (N1) of the turbine engine (11) is greater than a threshold difference and o A battery level is above a battery threshold, - determining (22) a low-pressure torque command (TRQBP) when it has been determined that a low-pressure electrical hybridization activation (GIDL) must take place.

Description

DESCRIPTION TITLE: Method for controlling a hybridized turbomachine TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of turbomachinery control.

[0002] The present invention falls within the field of aircraft propulsion, and more particularly turbomachinery using electric machines coupled to transmission shafts to provide additional power. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0004] Technological research efforts have already led to significant improvements in the environmental performance of aircraft. The Applicant takes into account factors impacting 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 in civil aviation have moderate environmental impacts, with the aim of improving aircraft energy efficiency. Consequently, the Applicant is continuously working to reduce its climate impact by employing methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible, thereby reducing the environmental footprint of its activities.

[0005] This sustained research and development work focuses in particular on the use of electrical technologies for propulsion. In In this context, hybridized turbomachinery with hybridization on the low pressure and / or high pressure bodies is known from the prior art.

[0006] Such a turbomachine is schematically represented in Figure 1. As is known, the turbomachine 10 comprises, from upstream to downstream in the direction of gas flow, a fan 100, a low-pressure compressor 101, a high-pressure compressor 102, a combustion chamber 103 which receives a WFCMD fuel flow control, a high-pressure turbine 104, a low-pressure turbine 105, and a primary exhaust nozzle 106. The low-pressure (LP) compressor 101 and the low-pressure turbine 105 are connected by a low-pressure shaft 111 and together form a low-pressure housing. The high-pressure (HP) compressor 102 and the high-pressure turbine 104 are connected by a high-pressure shaft 112 and together, with the combustion chamber, form a high-pressure housing. The blower 100, which is driven by the shaft BP 111, compresses the ingested air.This air is divided downstream of the blower 100 between a secondary airflow which is directed directly to a secondary nozzle (not shown) through which it is ejected to participate in the thrust provided by the turbomachine 10, and a so-called primary flow which enters the gas generator, consisting of the low pressure body and the high pressure body, and is then ejected into the primary nozzle 106.

[0007] In order to improve the response time of a turbomachine during a transient phase (acceleration, deceleration, etc.), and / or in order to complement fuel injection and thus reduce fuel consumption, it has been proposed to equip the turbomachine with electric motors in order to provide additional electrical torque to increase the speed of the turbomachine without leading to a pumping phenomenon.

[0008] Such a turbomachine may, for example, include: an electric motor forming a mechanical power injection device on the low-pressure rotating shaft 111 and / or an electric motor forming a mechanical power injection device on the high-pressure rotating shaft 112, a power extraction device on at least one of the rotating shafts, sized to extract excess power relative to as needed for actuation of turbomachine servicing, transforming excess power into electrical energy, and an electrical storage means positioned between the power extraction device and the electric motor(s).

[0009] Each electric motor and the shaft to which it is coupled are managed by a control system that dynamically adjusts the power supplied by the electric motor according to operating conditions and the power requirements of the turbomachine. Energy management becomes more complex with this hybrid configuration, requiring coordination between the electric motor and the associated turbine to maximize energy conversion efficiency.

[0010] One expressed need is for a control system to enable a hybrid turbomachine, and in particular a control system that allows for a more responsive engine at idle during taxiing. Indeed, during the taxiing phase, that is, when the aircraft is moving on the ground without any intention of takeoff, prior art turbomachines encounter a responsiveness problem: the engine takes a certain amount of time to reach operating speed to allow the aircraft to move.

[0011] Furthermore, this need for responsiveness is accentuated when the engine idle speed is even lower than that of a non-hybridized turbomachine. This reduction in engine idle speed reduces thrust to prevent premature brake wear. When thrust is reduced, the low-pressure N1 rotational speed is slowed by drawing electrical power from the low-pressure shaft 111 while maintaining the acceleration time, as illustrated in Figure 2.

[0012] Figure 2 shows a schematic representation of power extraction as a function of the low-pressure body N1 and high-pressure body N2 regimes. The high-pressure idle regime N2 is represented by the line N2idle, and the minimum low-pressure regime N1 is represented by the line N1 Min. When electrical power is extracted by the aircraft solely from the high-pressure body, the low-pressure regime N1 increases, as represented by the line "HP". In other words, thrust necessarily increases for the same high-pressure idle regime N2idle, but since the aircraft is not moving, It is necessary to brake more to compensate for this additional thrust, which results in brake wear.

[0013] To prevent premature brake wear in a hybrid turbomachine, when the aircraft requires electrical power, it is proposed to initially draw some of the necessary electrical power from the low-pressure shaft 111, represented by the line "BP". The low-pressure speed will then decrease, thus reducing thrust and preventing premature brake wear. However, this is no longer possible below the minimum low-pressure speed threshold N1 Min, so it is necessary to compensate by drawing power from the high-pressure shaft, which raises the low-pressure speed, represented by the line "BP+HP >>". In such a case, to increase thrust and move the aircraft, the initial low-pressure speed N1 is lower than the initial low-pressure speed when electrical power is drawn solely from the high-pressure shaft.Therefore, there is an even greater need for responsiveness, because the initial low pressure N1 regime is lower and the turbomachine then takes longer to reach high thrust setpoints. SUMMARY OF THE INVENTION

[0014] The invention offers a solution to the problems mentioned above, by proposing a turbomachine control that allows for a more responsive turbomachine, particularly at idle during the rolling phase.

[0015] One aspect of the invention relates to a computer-implemented method for controlling an aircraft turbomachine, the turbomachine being hybridized at least on a low-pressure body by comprising a low-pressure electric motor forming a device for injecting or extracting torque on a low-pressure rotating shaft of the turbomachine, the method comprising: acquiring a low-pressure speed setpoint of the turbomachine and a current low-pressure speed value of the turbomachine, determining that a low-pressure electric hybridization activation should take place when all of the following conditions are met: The low-pressure operating temperature setpoint is below a predefined thrust threshold. A difference between the low-pressure turbomachine setpoint and the actual low-pressure turbomachine setpoint exceeds a predefined difference threshold for a predetermined duration andA battery level is above a predefined battery threshold; determine a low-pressure torque command supplied to the low-pressure electric motor by at least one first torque control loop when it has been determined that a low-pressure electric hybridization activation must take place; the first torque control loop determining the low-pressure torque command as a function of the low-pressure speed setpoint and the current low-pressure speed value of the turbomachine; determine a fuel flow command in the combustion chamber by at least one first fuel control loop, including: comparing the low-pressure torque command to a maximum torque applicable to the low-pressure electric motor to obtain a torque difference; determine, by the first fuel control loop, the fuel flow command as a function of the torque difference.by calculating, in a closed loop, the fuel flow rate required to reduce the torque difference to zero.

[0016] The invention improves the responsiveness of the turbomachine, meaning its ability to react quickly to setpoint changes (in this case, engine speed), particularly during low-speed ground operations such as taxiing, by prioritizing the injection of electrical power on the low-pressure shaft. This approach leverages the faster response time of electrical power transfer compared to fuel flow adjustments, resulting in quicker acceleration and improved operational efficiency.

[0017] The invention enables improved responsiveness to low-pressure engine speed commands for taxiing the aircraft by using an electric hybridization activation indicator. This indicator allows the system to select when to inject electrical power into the low-pressure drive shaft when several conditions are met, such as during taxiing, and to stop this power injection and perform fuel injection during acceleration. The invention also facilitates the use of motive power from an installed electric motor to directly transmit mechanical torque to the low-pressure shaft. In this case, the invention uses fuel as a supplementary power source to control the low-pressure engine speed when the electric motor's power limits are reached, thereby minimizing fuel consumption.

[0018] Finally, the invention makes it possible, by minimizing fuel use, to limit the emission of polluting gases.

[0019] In addition to the features mentioned in the preceding paragraph, the method according to one aspect of the invention may have one or more of the following complementary features, considered individually or in all technically possible combinations: at least one of the following conditions must also be met to determine that low-pressure electric hybridization activation should occur: the low-pressure speed setpoint is greater than the current low-pressure speed value, the turbomachine idles, the aircraft including the turbomachine is on the ground, and the electric hybrid propulsion system is functional. The low-pressure speed of the turbomachine is controlled via a parameter chosen from among the turbomachine fan speed, the turbomachine EPR pressure ratio, and the power absorbed by the turbomachine fan. The determination of the torque command supplied to the low-pressure electric motor includes: determining a first torque command by a first control loop as a function of a low-pressure turbomachine speed setpoint to be reached and a current low-pressure speed value, determining a second torque command by a second control loop as a function of a low-pressure turbomachine speed acceleration trajectory to be followed and a current low-pressure speed value, Selection of a torque command from the first and second determined torque commands, based on the value of an acceleration indicator. The method further includes determining a high-pressure torque control supplied to a high-pressure electric motor of the turbomachine by at least a second torque control loop when it has been determined that a low-pressure electric hybridization activation is to take place, the second torque control loop seeking to return the high-pressure torque control to a zero value. The method includes at least one of the following steps: determining, by means of a second fuel control loop, a fuel flow control in the combustion chamber as a function of a high-pressure speed measurement to follow a high-pressure speed deceleration trajectory; determining, by means of a third fuel control loop, a fuel flow control in the combustion chamber as a function of a low-pressure speed measurement to follow a low-pressure speed acceleration trajectory. to determine, by means of a fourth fuel control loop, a fuel flow control in the combustion chamber based on a low-pressure speed measurement to follow a low-pressure speed setpoint; to maintain the gas generator in an idle state by means of a fifth fuel control loop determining a fuel flow control in the combustion chamber; to maintain the gas generator above a minimum static pressure setpoint by means of a sixth fuel control loop determining a fuel flow control in the combustion chamber; to maintain the gas generator below a maximum high-pressure speed setpoint by means of a seventh fuel control loop determining a fuel flow control in the combustion chamber.to maintain the gas generator below a maximum static pressure setpoint by means of an eighth fuel regulation loop determining a fuel flow control in the combustion chamber.

[0020] Another aspect of the invention relates to an aircraft turbomachine comprising a turbomachine control processor configured to implement the process according to the invention, the turbomachine comprising at least: a fan positioned upstream of a gas generator and delimiting a primary flow and a secondary flow, said gas generator being traversed by the primary flow and comprising: a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine connected to said high-pressure compressor by a high-pressure rotating shaft, and a low-pressure turbine connected to said low-pressure compressor by a low-pressure rotating shaft and an electric motor forming a torque injection device on the low-pressure rotating shaft.

[0021] Yet another aspect of the invention relates to an aircraft comprising the turbomachine according to the invention.

[0022] Yet another aspect of the invention relates to a computer program product comprising instructions which, when the program is executed by a computer, lead the computer to implement the process according to the invention.

[0023] Yet another aspect of the invention relates to a computer-readable data carrier on which the computer program product according to the invention is recorded.

[0024] The invention finds a particularly interesting application for bringing responsiveness to hybridized turbomachines when the aircraft is moving on the ground, and for limiting the ecological footprint of turbomachines.

[0025] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0026] The figures are presented for illustrative purposes only and are in no way limiting to the invention. Figure 1 shows a schematic representation of a prior art turbomachine, Figure 2 shows a schematic representation of two operating modes of a prior art turbomachine, Figure 3 shows a schematic representation of one embodiment of a turbomachine for implementing the process according to the invention, Figure 4 shows a schematic representation of one embodiment of a process according to the invention, Figure 5 shows a schematic representation of a module for determining the value of an electrical hybridization activation indicator according to the invention, Figure 6 shows a schematic representation of a selection module for a low-pressure torque control according to the invention, Figure 7 shows a schematic representation of a fuel control selection module according to the invention, Figure 8 shows a schematic representation of a selection module for a high-pressure torque control according to the invention, Figure 9 shows a schematic representation of the regime setpoint monitoring according to several scenarios, Figure 10 shows a schematic representation of fuel setpoint monitoring under several scenarios, Figure 11 shows a schematic representation of the power injection on the turbomachine according to several scenarios. DETAILED DESCRIPTION

[0027] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0028] Figure 3 shows a schematic representation of a turbomachine according to a first embodiment for implementing a process according to the invention. The turbomachine 11 shown is a twin-spool / twin-flow turbomachine, but any turbomachine including a low-pressure casing, for example a triple-spool turbomachine, can be used to implement the invention.

[0029] The turbomachine 11 shown comprises, in a known manner, at least: a blower 100 positioned upstream of a gas generator 110 and delimiting a primary flow and a secondary flow, said gas generator 110 being traversed by the primary flow and comprising: a low pressure compressor 101, a high pressure compressor 102, a combustion chamber 103, a high pressure turbine 104 connected to said high pressure compressor 102 by a high pressure rotation shaft 112, and a low pressure turbine 105 connected to said low pressure compressor 101 by a low pressure rotation shaft 111.

[0030] The turbomachine 11 has components identical to those of the prior art, and further includes an electric motor M1, forming a torque injection device on the low pressure rotating shaft 111, configured to provide additional torque to the low pressure shaft 111. In the following description, the motor M1 may be referred to as the "low pressure motor M1".

[0031] In the embodiment shown in Figure 3, the turbomachine 11 includes a second electric motor M2, forming a torque injection device on the high-pressure rotating shaft 112, configured to provide additional torque to the high-pressure shaft 112. In the remainder of this description, the motor M2 may be referred to as the "high-pressure motor M2". This second electric motor M2 is optional, and the invention is not limited to turbomachines hybridized on both the high-pressure and low-pressure sections. Indeed, the invention can be implemented on turbomachines hybridized only on the low-pressure section. In the remainder of this description, the example of a turbomachine 11 with two electric motors, low-pressure M1 and high-pressure M2, will be used, without this being limiting.

[0032] The turbomachine 11 also includes a torque-harvesting device (not shown) at least on the low-pressure rotation shaft 111, for example a battery or an "APU" (Auxiliary Power Unit).

[0033] The operation of the turbomachine 11 is controlled by an electronic unit P which obtains signals representing operating parameters of the turbomachine 11 to provide a flow control of WFCMD fuel in combustion chamber 103, a TRQBP low pressure torque control to electric motor M1, and a TRQHP high pressure torque control to electric motor M2.

[0034] The electronic entity P is for example a processor P for controlling the engine M, for example a computer called "FADEC", for "Full Automatic Digital Engine Control" (from the English "Fully Automatic Digital Engine Control").

[0035] The processor P is configured to implement a method for controlling the turbomachine 11. Alternatively, the method can be implemented by a computer included in the turbomachine 11, for example a computer such as a FADEC (Full Authority Digital Engine Control) system, or in an aircraft carrying the turbomachine 11, the computer communicating with the processor P.

[0036] A "computer" implementing the method according to the invention comprises at least one processor and one memory. The memory includes instructions which, when executed by the processor, cause the processor to implement the method according to the invention. In the course of implementing the method, the processor may store additional data in the memory or delete data stored in the memory.

[0037] The computer and the turbomachine can, for example, be embedded in an airborne system, for example in an aircraft.

[0038] The control method 20 according to the invention is shown in Figure 4. The control method 20 according to the invention first determines whether it is necessary to activate a low-pressure electrical hybridization of the turbomachine 11, during a first step 21.

[0039] For this purpose, and as illustrated in figure 5, the processor P includes a first module 30 for determining the value of a low-pressure electrical hybridization activation indicator GIDL.

[0040] According to the invention, the low-pressure electric hybridization activation indicator GIDL takes a first value when low-pressure electric hybridization needs to be activated, i.e., when it is necessary to provide a non-zero torque command to the low-pressure electric motor M1, and takes a second value when low-pressure electric hybridization needs to be deactivated. or should not be activated, that is, when it is not necessary to provide a non-zero torque command to the low-pressure electric motor M1, or when it is necessary to return the torque command of the low-pressure electric motor M1 to a zero value. For example, the GIDL indicator is a boolean taking a value of "True" or "False", or a bit taking a binary value of "1" or "0".

[0041] The GIDL indicator enables the turbomachine 11 to be responsive on the ground, meaning it allows the turbomachine's low-pressure hybrid system to be activated as soon as a number of conditions are met. The GIDL indicator determines the pilot's intentions by distinguishing whether the engine speed command is related to aircraft movement on the ground, i.e., a taxiing phase, or whether the engine speed command is for an acceleration trajectory, i.e., for significant transient phases starting from engine idle. By detecting a taxiing phase, the invention activates the injection of electrical power to the low-pressure shaft 111, thus enabling high responsiveness.By not detecting a rolling phase, the invention does not activate or deactivate the injection of electrical power on the low pressure shaft 111 and allows the expected operation of the turbomachine to be maintained, to reach an acceleration trajectory in a predefined time.

[0042] Step 21 therefore includes determining a value for each activation criterion for a plurality of criteria.

[0043] A first, optional criterion is that a setpoint for the N1 rotation speed of the low-pressure shaft 111 which drives the blower 100 is greater than the current value of the N1 speed.

[0044] The computer implementing process 20 therefore receives a current operating mode N1 of the turbomachine 11, and a setpoint N1C for the operating mode of the turbomachine 11 to be reached, for example, defined by the position of the control lever operated by the pilot of the aircraft including the turbomachine 11. The comparison of the setpoint N1C to the current operating mode N1 is performed by the operator ">" and the result (for example, true or false) is provided as input In2 of the multiplexer M1. This first optional criterion helps to avoid adverse effects such as glitches.

[0045] A second criterion is that the N1 C operating temperature setpoint must be lower than a predefined initial operating temperature threshold. Such a predefined initial operating temperature threshold is, for example, 30% of the maximum low-pressure operating temperature. This allows, in particular, to distinguish the aircraft pilot's intentions between a taxiing phase and a high-acceleration trajectory phase. A low-level hysteresis H1 can be implemented to react to exceedances of this first predefined engine speed threshold. The low-level hysteresis H1 comprises a high-level threshold S1 and a low-level threshold S2, defining the transition from the high state to the low state and vice versa. For example, the high-level threshold S1 is 30% of the maximum low-pressure engine speed, and the low-level threshold S2 is 28% of the maximum low-pressure engine speed. The result of the comparison (e.g., true or false) of the engine speed setpoint N1 C to the first predefined engine speed threshold (and optionally via the hysteresis H1) is provided at the In1 input of the multiplexer M1.

[0046] A third criterion is that the difference between the measured operating speed N1 and the setpoint operating speed N1 must be less than a predefined difference threshold for a predefined duration. For example, the predefined difference threshold is 50 rotations per minute of fan 100, and the predefined duration is 200 milliseconds. The difference is then N1 - N1C. This difference is compared to a predefined difference threshold. The absolute value of this difference can be compared to the predefined difference threshold. A hysteresis H2 can be implemented to react to exceedances of this difference threshold. For example, the hysteresis H2 can be a "high hysteresis," comprising two thresholds S3 and S4 to define the transition from the high state to the low state and vice versa. For example, the high threshold S3 is 50 rotations per minute of fan 100, and the low threshold S4 is 10 rotations per minute of fan 100.The result of the comparison (e.g., true or false) of the difference between the setpoint and the measured speed at the difference threshold (and optionally via the hysteresis H2) is provided as input to a time counter TC1, which checks whether the predefined difference threshold has been exceeded for a predefined duration. The result of this check (e.g., true or false) is provided as input In3 of the multiplexer M1.

[0047] The input to a second multiplexer M2 is provided the values ​​of a plurality of criteria C1 to C4.

[0048] A fourth criterion, C1, is that the battery level is above a predefined battery threshold, S5. This predefined battery threshold depends on the battery's size and is, for example, 10% of the battery's maximum charge to prevent complete discharge. To determine this, the battery level is compared to the threshold, S5, using a comparison operator ">". The level of Battery is the charge level of a battery or power supply system for the low-pressure electric motors M1 and / or high-pressure electric motors M2. The result of this comparison (e.g., true or false) is provided at input In 1 of the multiplexer M2.

[0049] A fifth, optional criterion, C2, is a check that the turbomachine 11 has reached idle speed. Idle speed is reached when the high-pressure core speed of the turbomachine reaches a predetermined value, known to those skilled in the art. The result of this check (e.g., true or false) is provided at input In2 of the multiplexer M2.

[0050] A sixth, optional criterion, C3, is that the aircraft containing the turbomachine 11 is on the ground, i.e., not in flight. This criterion C3 has a value of "true" if the aircraft is on the ground and a value of "false" if the aircraft is not on the ground. This ensures better responsiveness of the electric motors during taxiing, i.e., while on the ground. The result of this check (e.g., true or false) is provided at input In3 of the multiplexer M2.

[0051] A seventh, optional criterion, C4, is that a hybrid electric propulsion system (HPES) is functional. A functional hybrid electric propulsion system is, for example, one that does not exhibit any faults or anomalies. The result of this verification (e.g., true or false) is provided at input In4 of the M2 multiplexer.

[0052] Multiplexer M2 combines the inputs to provide an output value corresponding to "true" if all input criteria are "true". The output of multiplexer M2 is input In4 of multiplexer M1.

[0053] The M1 multiplexer combines the inputs to provide an output value corresponding to "true" if all input criteria are "true". The output of the M1 multiplexer is the value of the low-pressure electric hybridization activation indicator (GIDL). Thus, if all the aforementioned criteria are "true", then the GIDL indicator is "true" and low-pressure electric hybridization can be activated. If at least one of the criteria is "false", then low-pressure electric hybridization cannot be activated, presumably because the low-pressure engine speed setpoint corresponds to an acceleration trajectory and not a driving phase, or because one of the conditions unrelated to the engine speed setpoint is not met.

[0054] The low-pressure electric hybridization activation indicator GIDL is then used, according to the invention, to determine a low-pressure torque control TRQBP supplied to the engine M1, a high-pressure torque control TRQHP supplied to the engine M2 when the turbomachine is equipped with it, and a fuel control WFCMD in the combustion chamber 103.

[0055] In a second step 22, the computer implementing the process 20 determines a torque command TRQBP to be supplied to the low pressure electric motor M1, and therefore to be applied to the low pressure shaft 111. This determination is carried out by the low pressure torque command selection module 40, also called the "BP command selection module 40", shown in Figure 6.

[0056] This BP 40 command selection module notably uses the GIDL low pressure electric hybridization activation indicator.

[0057] To determine a TRQBP torque command to be supplied to the low pressure electric motor M1, and as schematically represented in Figure 6, the BP 40 control selection module receives a low pressure speed setpoint N1 C, a current measurement of the low pressure speed N1 and a low pressure speed acceleration trajectory N1T.

[0058] A first torque control loop receives the current N1 speed of the turbomachine 11, and the acceleration trajectory of the N1 speed of the turbomachine 11 to be built. A first correction network RC1, known to those skilled in the art, is configured to determine a first low-pressure torque command as a function of the N1T acceleration trajectory to be followed and the current value of the N1 speed.

[0059] A second torque control loop receives the current N1 speed of the turbomachine 11, and the setpoint N1C of the speed of the turbomachine 10 to be reached, for example defined by the position of the control lever manipulable by the pilot of the aircraft including the turbomachine 11. A second correction network RC2, known to the person skilled in the art, is configured to determine a second low pressure torque command as a function of the setpoint N1C of the speed of the turbomachine to be reached and the current value of the N1 speed.

[0060] The first and second low-pressure torque commands are provided as inputs to a switch 11. The switch 11 allows one of its two inputs at its output. Switch 11 is controlled by the value of the Acc acceleration indicator. Such an acceleration indicator has, for example, a value "true" when the difference between the N1 C engine speed setpoint and the current N1 engine speed is greater than a second predefined engine speed threshold, less than the first predefined engine speed threshold of the second criterion of the low-pressure electric hybridization activation indicator GIDL, which makes it possible to construct an acceleration trajectory while remaining in the driving phase.

[0061] Such an acceleration indicator, for example, has a "false" value when the difference between the setpoint speed N1 C and the current speed N1 is less than this second threshold. Thus, when the acceleration indicator is true, the low-pressure torque command from the first correction network RC1, which allows the N1T speed trajectory to be established, is supplied at the output of switch 11. In this case, the acceleration trajectory allows the engine to reach a speed lower than the first predefined speed threshold of the second criterion of the low-pressure electric hybridization activation indicator GIDL. When the acceleration indicator is false, the low-pressure torque command from the second correction network RC2, which allows the engine to follow the setpoint speed N1 G, is supplied at the output of switch 11.

[0062] The output of this switch 11 is supplied to one of the inputs of switch I2, which is itself controlled by the low-pressure electric hybridization activation indicator GIDL.

[0063] When the low-pressure electric hybridization activation indicator GIDL is "true", a torque command is supplied to the low-pressure shaft 111, so the input corresponding to the output of switch 11 is supplied to the output of switch I2. When, on the contrary, the low-pressure electric hybridization activation indicator GIDL is "false", the torque command supplied to the low-pressure shaft 111 is gradually reset to zero by means of a zero-reset correction network RC3 known to those skilled in the art, for example allowing the low-pressure torque command to follow an inverse exponential until it reaches a zero torque command.

[0064] The BP 40 command selection module also includes a network of "Min" and "Max" operators associated respectively with a first threshold M1 BP and to a second threshold M2BP. The first threshold M1BP is, for example, a maximum torque limit M1BP that can be injected onto the low-pressure shaft 111 by the low-pressure electric motor M1, a capacity limit of the machine or transmission chain, or any other limit. The second threshold M2BP is, for example, a maximum torque limit that can be extracted from the low-pressure shaft 111.

[0065] At the output of the BP 40 control selection module, a TRQBP torque command of the low-pressure electric motor M1 is obtained. The invention makes it possible, through the use of the low-pressure electric hybridization activation indicator GIDL, to select a non-zero low-pressure torque or to reduce the low-pressure torque to a zero value, when the conditions are no longer met and the aircraft is no longer in a taxiing phase and it is necessary to follow a trajectory of strong acceleration (above the first predefined speed threshold of the second criterion of the low-pressure electric hybridization activation indicator GIDL).

[0066] The invention also allows, when the low-pressure torque injected by the electric motor M1 reaches a stop, i.e. reaches a maximum threshold of injectable torque, to compensate for the torque deficit to reach the setpoint by an injection of fuel.

[0067] Thus, process 20 includes a step 23 of determining a WFCMD fuel flow control in the combustion chamber 103.

[0068] This step 23 is carried out by a fuel order selection module 50 represented schematically in Figure 7.

[0069] The fuel order selection module 50 shown in Figure 7 comprises eight fuel regulation loops, B1 to B8. This representation is an example of implementation and is not intended to be limiting. Only fuel regulation loop B1 is essential for implementing the invention. The other fuel regulation loops, B2 to B8, each determine a fuel order based on a criterion to be met, and module 50 allows the selection of a fuel order from one of these loops.

[0070] The first control loop, B1, aims to use turbomachine fuel sparingly. Therefore, fuel is only supplied by loop B1 when the low-pressure torque control, TRQBP, is throttled. in its operating range, i.e. for example when the TRQBP torque control reaches a maximum M1 BP threshold of torque injection on the low pressure shaft 111 and the low pressure operating speed setpoint N1 C is not reached.

[0071] Therefore, the first fuel regulation loop, B1, takes as input the low-pressure torque command TRQBP from the low-pressure control selection module 40, as well as the limit switch of the electric motor M, for example, the maximum torque TRQMAX of the electric motor M. The first fuel loop, B1, includes a correction network (not shown) that takes as input the torque difference between the low-pressure torque TRQBP and the maximum torque TRQMAX and provides as output a fuel command. The correction network of loop B1 is configured to try to bring the torque difference to zero. Thus, the correction network will increment the fuel flow command when the torque difference is positive and will provide a decremented fuel flow command to bring it to zero when the torque difference is negative.Thus, step 23 includes a first sub-step of comparing the low pressure torque control TRQBP to a maximum torque TRQBPMAX applicable to the low pressure electric motor M1 to obtain a torque difference ATRQ, and a second sub-step of determining, by the first fuel regulation loop B1, a fuel control as a function of the torque difference ATRQ, by calculating in closed loop the fuel flow required to bring the torque difference ATRQ back to a zero value.

[0072] In a second embodiment of the method according to the invention, the control system comprises a plurality of fuel control loops B2 to B8. Each fuel control loop B2 to B8 provides a different fuel command output, determined as a function of a different parameter monitored by the respective fuel control loop. In this second embodiment, the control system comprises at least one second fuel control loop, for example, the B2 fuel control loop. Figure 7 shows seven additional fuel control loops B3 to B8, but the invention covers any number of fuel control loops, not limited to the example shown in Figure 7. Each control loop comprises at least one correction network, which determines a fuel command based on a difference value (of engine speed, torque, or pressure, for example) that it receives input. The controllers can, for example, be phase-lead type controllers whose transfer function can be, but not limited to, one of the following forms: Transfer function at p: — - k Transfer function With Te the processing period of the processor P, T and K the gains of the corrector known to a person skilled in the art and not limiting for the invention.

[0073] The form of the correction networks (CR) is not limiting for the invention and can take any other forms known to the person skilled in the art such as PI, PID, state feedback corrector etc.

[0074] In the example shown in Figure 7, the second fuel control loop B2 monitors a speed parameter N2 of the high-pressure shaft 112 and ensures that it follows a high-pressure speed acceleration trajectory N2T. The second control loop B2 provides an output fuel command to maintain this high-pressure speed acceleration trajectory N2T.

[0075] In the example in Figure 7, the third fuel control loop B3 monitors a low-pressure shaft speed parameter N1 and ensures that it follows an acceleration trajectory corresponding to the high-pressure speed N1T. The third control loop B3 provides an output fuel command to maintain this low-pressure speed acceleration trajectory N1T.

[0076] In the example in Figure 7, the fourth fuel control loop B4 monitors a speed parameter N1 of the low-pressure shaft 111, and ensures that it follows a low-pressure speed setpoint N1 C. The fourth fuel control loop B4 provides an output fuel command to maintain this low-pressure speed setpoint N1 C.

[0077] In the example in Figure 7, the fifth fuel control loop B5 monitors a speed parameter N2 of the high-pressure shaft 112 and ensures that it reaches an idle speed setpoint N2ldle. The fifth fuel loop B5 provides an output fuel control signal enabling to respect this idle speed criterion N2ldle. This fuel regulation loop B5 allows the gas generator 110 to be maintained in an idle state, which allows its economical use and prioritizes the use of the electric motor BP M1 via the torque control selection module 40. The gas generator 110 is thus ready to supplement the power supplied by the electric motor BP M1 via the low-pressure torque control TRQBP in the event that the low-pressure torque control TRQBP encounters a limitation.

[0078] In the example shown in Figure 7, the sixth fuel control loop B6 monitors a static pressure parameter Ps3 measured at the outlet of combustion chamber 103 and ensures that it does not fall below a threshold Ps3Min. The sixth fuel control loop B6 provides an output fuel command to maintain this minimum static pressure criterion Ps3Min.

[0079] In the example shown in Figure 7, the seventh fuel control loop B7 monitors a speed parameter N2 of the high-pressure shaft 112 and ensures that it does not exceed a speed threshold N2Max. The seventh fuel control loop B7 outputs a fuel command to maintain this N2Max speed threshold.

[0080] In the example shown in Figure 7, the eighth fuel control loop B8 monitors a static pressure parameter Ps3 measured at the outlet of combustion chamber 103 and ensures that it does not rise above a threshold Ps3Max. The eighth fuel control loop B8 provides an output fuel command to maintain this maximum static pressure criterion Ps3Max.

[0081] Thus, in the example shown in Figure 7, the control system must manage eight different fuel commands, originating from fuel control loops B1 to B8, each linked to a different need. Therefore, in any embodiment with multiple fuel control loops, it is necessary to use a network of Min and Max operators and switches, as shown in Figure 7, to select a fuel command from among those obtained.

[0082] This is achieved in step 23, which allows the selection of a fuel command from among a plurality of fuel commands originating from different fuel regulation loops. For example, in Figure 7, a "Max" operator allows the selection of the highest fuel command value from among the commands originating from loops B5, which aims to maintain the high-pressure idle speed N2ldle, and B6, which aims to maintain the static pressure Ps3 above a minimum threshold Ps3Min.The output of this "Max" operator is the input of two other "Max" operators: a second "Max" operator selecting the highest torque command from among those from loop B1, which seeks to compensate for the low-pressure motor M1's torque deficit, and those from the "Max" operators of loops B5 and B6; and a third "Max" operator selecting the highest torque command from those from loop B4, which seeks to follow the low-pressure setpoint N1 C, and those from the "Max" operators of loops B5 and B6. The output of the second "Max" operator is the input of a switch I5 controlled by the low-pressure electric hybridization activation indicator GIDL. The output of the third "Max" operator is the input of a "Min" operator.This "Min" operator also receives as input the fuel commands from loops B7, which aims to maintain the high-pressure engine speed below a threshold N2Max, and B8, which aims to maintain the static pressure below a threshold Ps3Max. It therefore selects the minimum value among the three fuel commands. The output of this "Min" operator is the input to a switch I3 controlled by the "Acc" acceleration indicator. This indicator allows the selection between the fuel command from the "Min" operator and the fuel command from the third loop, B3, which aims to follow a low-pressure engine speed acceleration trajectory N1T.

[0083] The output of switch I3 is the input of switch I4, which is controlled by a deceleration indicator "Dec". This indicator allows selection between the fuel command from switch I3 and the fuel command from the second loop B2, which aims to follow a high-pressure N2T acceleration trajectory. The output of switch I4 is the input of switch I5, which is controlled by the low-pressure electric hybridization activation indicator GIDL. Switch I5 also receives the output of the second operator "Max" as input.

[0084] The output of switch 15 is the input of a fourth operator "Max", which also takes as input an extinction fuel threshold M1 WF below which the final fuel command must not fall.

[0085] The output of the fourth operator, "Max," is the input of a second operator, "Min," which also takes as input a fuel acceleration threshold, M2WF, beyond which the final fuel command must not pass. The final fuel command, WFCMD, is thus obtained by the fuel control selection module 50, using a plurality of fuel regulation loops and a network of "Min," "Max," and switch operators. The final fuel flow command, WFCMD, will therefore either maintain the turbomachine 11 in operating condition or supplement the power required by the TRQBP electric torque to ensure thrust control under responsive conditions.

[0086] When the turbomachine implementing the process according to the invention includes an electric motor injecting power onto the high-pressure shaft 112, for example in the case of the turbomachine 11 shown in Figure 3, the process according to the invention may further include a step 24 for determining a high-pressure torque control TRQHP.

[0087] This step 24 is carried out by a high pressure torque control selection module 60 represented schematically in Figure 8.

[0088] The selection module 60 shown in Figure 8 is a TRQHP high-pressure torque control selection module known to those skilled in the art, to which a progressive reset loop has been added, including the Z delay operator. -1 and the RC4 correction network, at the input of a switch I7 controlled by the low pressure electrical hybridization activation indicator GIDL.

[0089] On the lower part of module 60, known to those skilled in the art, two high-pressure torque control loops each provide high-pressure torque control.

[0090] The first loop B9 seeks to prevent the exhaust gas temperature ("Exhaust Gas Temperature" or "EGT >>") from reaching a maximum threshold.

[0091] The second loop B10 only provides high-pressure torque control when the WFCMD fuel control is restricted within its operating range, i.e., for example, when the WFCMD fuel control The maximum fuel level in combustion chamber 103 is reached (WFMax), and the low-pressure operating speed setpoint (N1 C) is not achieved. Therefore, the second high-pressure torque control loop (B10) takes as input the WFCMD fuel command from the fuel command selection module 50, as well as the WFMax fuel limit. The second high-pressure torque control loop (B10) includes a correction network (not shown) that takes as input the fuel difference between the WFCMD command and the maximum fuel level (WFMax) and provides as output a high-pressure torque command. The correction network of loop B1 is configured to attempt to reduce the fuel difference to zero.Thus, the correction network will increment the high-pressure torque command when the fuel difference is positive, and the correction network will provide a decremented high-pressure torque command to bring it to zero when the fuel difference is negative. Therefore, step 24 includes a first substep comparing the WFCMD fuel command to a maximum fuel WFMax to obtain a fuel difference AWF, and a second substep determining, by the second HP torque control loop B10, a high-pressure torque command based on the fuel difference AWF, by calculating in closed loop the high-pressure torque required to bring the fuel difference AWF to zero.

[0092] The two high-pressure torque commands provided by the B9 and B10 control loops are compared by a first operator "Max", which provides on its output the highest high-pressure torque command among the input high-pressure torque commands.

[0093] The output of the first operator "Max" is the input of a second operator "Max", as well as a threshold S6 which is a low-torque limit for high-pressure injection on the high-pressure shaft 112. The threshold S6 prevents the control loops B9 and B10 from requesting a draw on the high-pressure shaft. The high-pressure torque command at the output of the second operator "Max" is summed with a value from a deceleration block, comprising a motor measurement MA, a torque draw law on the high-pressure shaft in open loop during the deceleration phase, and a switch controlled by an indicator. deceleration allowing you to choose an output between the value from the deceleration block and a zero value.

[0094] This sum is supplied to the input of switch 17, with the other input being the output of the RC4 reset correction network. Switch 17 is controlled by the GIDL low-pressure electric hybridization activation indicator. The output of this switch 17 is the input of switch 18, which is controlled by an idle speed indicator. If a high-pressure body idle speed is reached, the output of switch 17 is connected to the output of switch 18. If the high-pressure body idle speed is not reached, switch 18 is toggled to an input consisting of an MB engine measurement and an acceleration block.

[0095] The output of switch 18 is then the input of a third operator "Max", also taking as input a minimum high pressure torque threshold M1 HP below which the final high pressure torque command must not pass.

[0096] The output of the third operator, "Max," is the input of an operator, "Min," which also takes as input a maximum high-pressure torque threshold, M2HP, beyond which the final high-pressure torque control must not pass. The final TRQHP control is thus obtained by the high-pressure torque control selection module 60, using a plurality of high-pressure torque control loops and a network of "Min," "Max," and switch operators. The final high-pressure torque control, TRQHP, will therefore either maintain the turbomachine 11 in operating condition or supplement the power required by the WFCMD fuel to ensure thrust control outside of reactive conditions.Indeed, thanks to the use of the low-pressure electric hybridization activation indicator GIDL, the high-pressure torque is gradually returned to a zero value under reactivity conditions, and is only activated outside of reactivity conditions.

[0097] Figure 9 shows a schematic representation of the low-pressure N1 regime as a function of time, according to different scenarios. The low-pressure N1 regime setpoint C is represented by curve A. The responsiveness conditions are met, i.e., the activation indicator of the low-pressure electrical hybridization GIDL according to the invention has a value of "true". Curve B represents a scenario in which the invention is implemented, and curve G represents a scenario in which the invention is not implemented. The setpoint is approached and reached much more quickly, almost twice as quickly, with the reactivity assistance according to the invention, compared to the prior art case of a hybridized turbomachine without the reactivity assistance of the invention.

[0098] Figure 10 shows a schematic representation of the fuel control WF in the combustion chamber 103 as a function of time, according to different scenarios. The curves WFMaxA and WFMaxB are the fuel limits, respectively without and with the invention. Since the invention prioritizes low-pressure torque assistance TRQBP before fuel consumption, the fuel limit WFMaxB is lower than the fuel limit WFMaxA, and the fuel limit WFMaxB with assistance is reached by the fuel setpoint WFCB much later than the fuel limit WFMaxA without assistance is reached by the fuel setpoint WFCA without assistance, which reaches the WFMaxA limit almost at the beginning of the thrust. The fuel consumption WFCB is significantly lower with the responsiveness assistance of the invention than without WFCB assistance.

[0099] Figure 11 shows a schematic representation of the turbomachine's power output (PW) as a function of time, according to different scenarios. Curve D shows the power output with the responsiveness assistance provided by the low-pressure torque (TRQBP) according to the invention, and curve E shows the power output without this assistance. It is clear that the power output is much higher according to the invention, and that it decreases rapidly when the responsiveness conditions (the conditions of the electric hybridization activation indicator) are no longer met, as represented by the inverse exponential decay of curve D. Curve E is stable because the assistance of the invention is not present, and the turbomachine is therefore less responsive than in the invention; that is, the power output does not react quickly to changes in setpoints when the responsiveness conditions are met.

Claims

Tl DEMANDS

1. A computer-implemented method for controlling an aircraft turbomachine, the turbomachine being hybridized at least on a low-pressure body by comprising a low-pressure electric motor forming a device for injecting or extracting torque on a low-pressure rotating shaft of the turbomachine, the method comprising: - acquire a low-pressure operating speed setpoint (N1 C) for the turbomachine and a current low-pressure operating speed value (N1) for the turbomachine, - determine (21) that a low-pressure electric hybridization (GIDL) activation must take place when all of the following conditions are met: o The low-pressure speed setpoint (N1C) is below a predefined thrust threshold, o A difference between the low-pressure speed setpoint (N1C) of the turbomachine (11) and the current low-pressure speed value (N1) of the turbomachine (11) is greater than a predefined difference threshold for a predetermined duration, and o A battery level is above a predefined battery threshold, - determine (22) a low-pressure torque control (TRQBP) supplied to the low-pressure electric motor (M1) by at least a first torque control loop when it has been determined that a low-pressure electric hybridization activation (GIDL) is to take place, the first torque control loop determining the low-pressure torque control (TRQBP) as a function of the low-pressure speed setpoint (N1 C) and the current low-pressure speed value (N1) of the turbomachine, - determine (23) a fuel flow control (WFCMD) in the combustion chamber by at least one first fuel control loop (B1), comprising: o compare the low pressure torque control (TRQBP) to a maximum torque (TRQMAX) applicable to the low pressure electric motor (M1) to obtain a torque difference, o determine, by the first fuel regulation loop (B1), the fuel flow control (WFCMD) as a function of the torque difference, by calculating in closed loop the fuel flow required to bring the torque difference back to a zero value.

2. A method (20) according to the preceding claim wherein at least one of the following conditions must also be met to determine (21) that low-pressure electric hybridization (LIHE) activation must take place: - the low pressure operating regime setpoint (N1 C) is greater than the current low pressure operating regime value (N1 ), - a slowdown of the turbomachine (11) is reached, - the aircraft including the turbomachine (11) is on the ground, - The hybrid electric propulsion system is functional.

3. A method (20) according to any one of the preceding claims wherein the low pressure regime (N1) of the turbomachine (11) is controlled via a parameter selected from the turbomachine blower regime, the turbomachine EPR pressure ratio, the power absorbed by the turbomachine blower.

4. A method (20) according to any one of the preceding claims, wherein the determination (22) of the torque control supplied to the low-pressure electric motor comprises: - determination of a first torque command by a first control loop as a function of the low pressure speed setpoint of the turbomachine (N1 C) to be reached and the current value of low pressure speed (N1 ), - determination of a second torque command by a second control loop as a function of an acceleration trajectory (N1T) of low-pressure operating speed of the turbomachine to be monitored and the current low-pressure operating speed value (N1), - Selection of a torque command (TRQBP) from the first torque command and the second torque command determined, based on the value of an acceleration indicator (Acc).

5. Method (20) according to any one of the preceding claims further comprising determining (24) a high-pressure torque control (TRQHP) supplied to a high-pressure electric motor (M2) of the turbomachine (11) by at least a second torque control loop when it has been determined that a low-pressure electric hybridization activation (GIDL) is to take place, the second torque control loop seeking to return the high-pressure torque control (TRQHP) to a zero value.

6. A method (20) according to any one of the preceding claims comprising at least one of the following steps: - determine, by means of a second fuel regulation loop (B2), a fuel flow control (WFCMD) in the combustion chamber (103) as a function of a high-pressure speed measurement (N2) to follow a high-pressure speed deceleration trajectory (N2T), - determine, by means of a third fuel regulation loop (B3), a fuel flow control (WFCMD) in the combustion chamber (103) as a function of the current low-pressure speed value (N1) to follow a low-pressure speed acceleration trajectory (N1T), - determine, by means of a fourth fuel regulation loop (B4), a fuel flow control (WFCMD) in the combustion chamber (103) as a function of the current low-pressure operating speed value (N1) to follow the low-pressure operating speed setpoint (N1 C), - maintain the gas generator (110) in an idle state (N2ldle) by a fifth fuel regulation loop (B5) determining a fuel flow control (WFCMD) in the combustion chamber (103), - maintain the gas generator (110) above a minimum static pressure setpoint (Ps3Min) by means of a sixth fuel regulation loop (B6) determining a fuel flow control (WFCMD) in the combustion chamber (103), - maintain the gas generator (110) below a maximum high-pressure setpoint (N2Max) by means of a seventh fuel regulation loop (B7) determining a fuel flow control (WFCMD) in the combustion chamber (103), - maintain the gas generator (110) below a maximum static pressure setpoint (Ps3Max) by an eighth fuel regulation loop (B8) determining a fuel flow control (WFCMD) in the combustion chamber (103).

7. Aircraft turbomachine (11) comprising a control processor (P) for the turbomachine (11) configured to implement the method (20) according to any one of the preceding claims, the turbomachine (11) comprising at least: - a blower (100) positioned upstream of a gas generator (110) and defining a primary flow and a secondary flow, - said gas generator (110) being traversed by the primary flow and comprising: o a low pressure compressor (101 ), o a high pressure compressor (102), o a combustion chamber (103), o a high pressure turbine (104) connected to said high pressure compressor (102) by a high pressure rotation shaft (112), and o a low pressure turbine (105) connected to said low pressure compressor (101 ) by a low pressure rotation shaft (111 ) and a low pressure electric motor (M1) forming a torque injection device on the low pressure rotation shaft (111 ).

8. Aircraft comprising the turbomachine (11) according to claim 7.

9. Product computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method (20) according to any one of claims 1 to 6.

10. Computer-readable data carrier on which the computer program product according to claim 9 is recorded.

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