Method for controlling a hybridized turbomachine

Abstract

One aspect of the invention relates to a method for controlling a low-pressure hybrid aircraft turbomachine comprising: acquiring a low-pressure speed setpoint (N1C) and a current low-pressure speed value (N1); determining (21) that a low-pressure electric hybridization activation (GIDL) should occur when: the low-pressure speed setpoint (N1C) is below a thrust threshold; 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 difference threshold; and a battery level is above a battery threshold; determining (22) a low-pressure torque control (TRQBP) when it has been determined that a low-pressure electric hybridization activation (GIDL) should occur. Figure to be published with the abstract: Figure 5

Description

Title of the invention: Method for controlling a hybrid turbomachine. TECHNICAL FIELD OF THE INVENTION

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

[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 various states. In particular, an ambitious standard applies to both new types of aircraft and those currently 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 very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order 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 the energy efficiency of aircraft. Consequently, the Applicant is constantly 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 in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses in particular on the use of electrical technologies for propulsion. 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 [Fig. 1]. As is known, the turbomachine 10 comprises, from upstream to downstream in the direction of gas flow, a blower 100, a low-pressure compressor 101, a high-pressure compressor 102, and a combustion chamber 103 which receives a flow control of The WFCMd fuel system consists of 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 unit. 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 unit. The blower 100, which is driven by the LP shaft 111, compresses the intake 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, comprise: • 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 the turbomachine's actuation requirements, converting the 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 the 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 the efficiency of energy conversion.

[0010] One expressed need is to enable control of a hybrid turbomachine, and in particular control enabling 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, the turbomachines Previous art encountered a problem of responsiveness: the engine takes some 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 is a reduction in thrust to prevent premature brake wear. When the thrust is reduced, the low-pressure rotational speed NI is slowed down by drawing electrical power from the low-pressure shaft 111 while maintaining the acceleration time, as illustrated in [Fig. 2].

[0012] Figure 2 shows a schematic representation of power extraction as a function of the low-pressure body's idle speed (NI) and the high-pressure body's idle speed (N2). The high-pressure idle speed (N2) is represented by the line N2idle, and the minimum low-pressure speed (NI) is represented by the line NIMin. When electrical power is extracted by the aircraft solely from the high-pressure body, the low-pressure speed (NI) increases, as represented by the line "HP". In other words, the thrust necessarily increases for the same high-pressure idle speed (N2idle), but since the aircraft is not moving, more braking is required to compensate for this additional thrust, resulting 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 NIMin, 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 NI is lower than the initial low-pressure speed when electrical power is drawn only from the high-pressure shaft.Therefore, there is an even greater need for responsiveness, because the initial low-pressure NI 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 allowing a more responsive turbomachine, particularly at idle during the rolling phase.

[0015] One aspect of the invention thus 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: • acquire a low-pressure turbomachine speed setpoint and a current low-pressure turbomachine speed value, • determine that a low-pressure electric hybridization activation must 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 and • A 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 control in the combustion chamber by at least one first fuel regulation loop, comprising: • compare the low-pressure torque control to the maximum torque applicable to the low-pressure electric motor to obtain a torque difference, • determine, by the first fuel regulation loop, the fuel flow control 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.

[0016] The invention improves the responsiveness of the turbomachine, that is, the turbomachine's rapid response to changes in setpoint (speed in this case), particularly during low-speed ground operations such as taxiing, by prioritizing the injection of electrical power on the low-pressure shaft. This approach takes advantage of the faster response time of the power transfer. electric versus fuel flow adjustments, resulting in faster 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, i.e., during taxiing, and to stop this power injection and perform fuel injection during acceleration. The invention also facilitates the use of motive power supplied by an installed electric motor to directly transmit mechanical torque to the low-pressure shaft. In this case, the invention uses fuel as a supplementary source to control the low-pressure engine speed when the power limits of the electric motor are reached, thereby minimizing fuel consumption.

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

[0019] In addition to the characteristics mentioned in the preceding paragraph, the method according to one aspect of the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: • at least one of the following conditions must also be met to determine that a low-pressure electric hybridization activation must take place: • The low-pressure operating temperature setpoint is higher than the current low-pressure operating temperature value. • the turbomachine idles, • the aircraft including the turbomachine is on the ground, • the hybrid electric propulsion system is functional. • The low-pressure operating mode of the turbomachine is controlled via a parameter chosen from the operating mode of the turbomachine blower, the EPR turbomachine pressure ratio, the power absorbed by the turbomachine blower. • Determining the torque command supplied to the low-pressure electric motor includes: • Determination of an initial torque command by a first control loop based on a target low-pressure turbomachine speed and a current low-pressure speed value, • Determination of a second torque command by a second control loop based on a low-pressure turbomachine 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 bring the high-pressure torque control back to a zero value. The process includes at least one of the following steps: • to determine, via a second fuel regulation loop, a fuel flow control in the combustion chamber as a function of a high-pressure engine speed measurement to follow a high-pressure engine speed deceleration trajectory, • determine, via a third fuel regulation loop, a fuel flow control in the combustion chamber as a function of a low-pressure engine speed measurement to follow a low-pressure engine speed acceleration trajectory, • determine, via a fourth fuel regulation loop, a fuel flow control in the combustion chamber based on a low-pressure speed measurement to follow a low-pressure speed setpoint, • maintain the gas generator in an idle state by means of a fifth fuel regulation loop determining a fuel flow control in the combustion chamber, • maintain the gas generator above a minimum static pressure setpoint by means of a sixth fuel regulation loop determining a fuel flow control in the combustion chamber, • maintain the gas generator below a maximum high-pressure setpoint by means of a seventh fuel regulation loop determining a fuel flow control in the combustion chamber, • maintain the gas generator below a maximum static pressure setpoint by 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 method according to the invention, the turbomachine comprising at least: • a blower positioned upstream of a gas generator, 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 latter 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 of the invention. • Figure [1] shows a schematic representation of a prior art turbomachine, • Figure [Fig. 2] shows a schematic representation of two modes of operation of a prior art turbomachine, • Figure [Fig. 3] shows a schematic representation of an embodiment of a turbomachine for implementing the process according to the invention, • Figure 4 shows a schematic representation of one embodiment of a method 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 low-pressure torque control selection module according to the invention, • Figure 7 shows a schematic representation of a selection module of a fuel control system 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 setpoint tracking of regime according to several scenarios • Figure 10 shows a schematic representation of fuel setpoint monitoring under several scenarios, • Fig. 11 shows a schematic representation of 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 method 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 102 high-pressure compressor, • a combustion chamber 103, • a high-pressure turbine 104 connected to said high-pressure compressor 102 by a high-pressure rotating 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 links components identical to those of the prior art, and further includes an electric motor Ml, forming a torque injection device on the low pressure rotation shaft 111, configured to provide additional torque to the low pressure shaft 111. In the following description, the motor Ml may be referred to as the "low pressure motor Ml".

[0031] In the embodiment of [Fig. 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 "Auxiliary Power Unit" (APU).

[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 fuel flow control WFCMD in the combustion chamber 103, a low pressure torque control TRQBP to the electric motor M1, and a high pressure torque control TRQHP to the 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 comprises 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 further 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 [Fig.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 [Fig.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 is to be activated, i.e., when it is necessary to provide a non-zero torque command to the low-pressure electric motor Ml, and takes a second value when low-pressure electric hybridization is to be deactivated or not to be activated, i.e., when it is not necessary to provide a non-zero torque command to the low-pressure electric motor Ml, or when it is necessary to return the torque command of the low-pressure electric motor ML to a zero value. For example, the GIDL indicator is a boolean taking a value "True" or "False", or a bit taking a binary value "1" or "0".

[0041] The GIDL indicator enables the turbomachine 11 to be responsive on the ground, meaning that it allows the turbomachine's low-pressure hybrid system to be activated as soon as a number of conditions are met. The GIDL indicator makes it possible to determine 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, in order 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 NI rotation speed of the low-pressure shaft 111 which drives the blower 100 is greater than the current NI speed value.

[0044] The computer implementing the process 20 therefore receives a current operating regime NI of the turbomachine 11, and a setpoint NIC of the operating regime of the turbomachine 11 to be reached, for example defined by the position of the control lever manipulable by the pilot of the aircraft comprising the turbomachine 11. The comparison of the setpoint NIC to the current operating regime NI is carried out by the operator « > » and the result (for example, true or false) is provided in input In2 of the multiplexer ML. This first optional criterion makes it possible to avoid adverse effects such as chatter.

[0045] A second criterion is that the NIC speed setpoint be lower than a first predefined speed threshold. Such a first predefined speed threshold is, for example, a threshold of 30% of the maximum low-pressure speed. This makes it possible, in particular, to distinguish the aircraft pilot's intentions between a taxiing phase and a high-acceleration trajectory phase. A low hysteresis H1 can be implemented to react to exceedances of this first predefined speed threshold. The low hysteresis H1 comprises a high threshold SI and a low threshold S2, allowing the transition from the high state to the low state and vice versa. For example, the high threshold SI is a threshold of 30% of the maximum low-pressure speed and the low threshold S2 is a threshold of 28% of the maximum low-pressure speed. The result of the comparison (for example, true or false) of the NIC speed setpoint to the first predefined speed threshold (and optionally via the hysteresis H1) is provided at the Inl input of the ML multiplexer.

[0046] A third criterion is that the difference between the measured operating speed NI 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 setpoint at the difference threshold (and optionally via the H2 hysteresis) is provided as input to a TCI time counter, which checks if the difference threshold. The predefined value has been exceeded for a predefined duration. The result of this check (e.g., true or false) is provided at input In3 of the multiplexer Ml.

[0047] The values ​​of a plurality of criteria Cl to C4 are provided as input to a second multiplexer M2.

[0048] A fourth criterion Cl is that a battery level is above a predefined battery threshold S5. Such a predefined battery threshold depends on the battery size and is, for example, 10% of the battery's maximum charge to prevent complete discharge. For this purpose, the battery level is compared to the threshold S5 using a comparison operator ">". The battery level is the charge level of a battery or a power supply system for low-pressure electric motors M1 and / or high-pressure electric motors M2. The result of this comparison (for example, true or false) is provided at the input In1 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 (for example, true or false) is provided at input In2 of the multiplexer M2.

[0050] A sixth, optional criterion, C3, is that the aircraft including the turbomachine 11 is on the ground, i.e., it is not in flight. This criterion C3 has, for example, 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 (for example, 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 report any anomalies. The result of this check (for example, true or false) is provided at input In4 of the multiplexer M2.

[0052] The multiplexer M2 combines the inputs to provide, as output, a value corresponding to "true" if all the input criteria have the value "true". The output of the multiplexer M2 is input In4 of the multiplexer ML

[0053] The multiplexer M1 combines the inputs to provide, at the output, a value corresponding to "true" if all the input criteria have the value "true". The output of the multiplexer M1 is the value of the low-pressure electric hybridization activation indicator GIDL. Thus, if all the criteria stated above have the value "true", then the GIDL indicator has the value "true" and the low-pressure electric hybridization can be activated. If at least one of the criteria has the value "false", then the low-pressure electric hybridization cannot be activated, presumably because the The low-pressure engine speed setting corresponds to an acceleration trajectory and not a driving phase, or because one of the conditions not related to the engine speed setting 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 M1 engine, a high-pressure torque control TRQHP supplied to the M2 engine 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 Ml, 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 [Fig.6].

[0056] This BP 40 control selection module uses in particular the low pressure electric hybridization activation indicator GIDL.

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

[0058] A first torque control loop receives the current speed NI of the turbomachine 11, and the acceleration trajectory of the speed NI 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 acceleration trajectory N1T to be followed and the current value of the speed NI.

[0059] A second torque control loop receives the current speed NI of the turbomachine 11, and the setpoint NIC 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 NIC of the speed of the turbomachine to be reached and the current value of the speed NI.

[0060] The first and second low-pressure torque commands are provided as inputs to a switch II. Switch II allows one of its two inputs to be connected to its output. Switch II is controlled by the value of the Acceleration Indicator Acc. Such an acceleration indicator has, for example, a "true" value when the difference between the setpoint speed NIC and the current speed NI is greater than one second predefined engine speed threshold, lower than the first predefined engine speed threshold of the second criterion of the low pressure electric hybridization activation indicator GIDL, which allows an acceleration trajectory to be built while remaining in the driving phase.

[0061] Such an acceleration indicator, for example, has a "false" value when the difference between the setpoint speed NIC and the current speed NI 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 II. 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 NIC, is supplied at the output of switch II.

[0062] The output of this switch II is supplied to one of the inputs of switch 12, which is itself controlled by the low-pressure electric hybridization activation indicator GIDL.

[0063] When the low-pressure electrical 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 II is supplied to the output of switch 12. When, on the contrary, the low-pressure electrical 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 control selection module further includes a network of "Min" and "Max" operators associated respectively with a first threshold M1BP and 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 control 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 torque low pressure to a value of zero, 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 (greater than the first predefined regime 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 Ml reaches a stop, that is to say reaches a maximum threshold of injectable torque, to compensate for the torque deficit to reach the setpoint by an injection of fuel.

[0067] Thus, the 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 control selection module 50 shown schematically in [Fig.7].

[0069] The fuel order selection module 50 shown in [Fig. 7] comprises eight fuel regulation loops B1 to B8. This representation is an example of an implementation and is in no way 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 the turbomachine's fuel sparingly. Thus, a fuel command is only provided by the loop B1 when the low-pressure torque command TRQBP is limited within its operating range, i.e. for example when the torque command TRQBP reaches a maximum torque injection threshold M1BP on the low-pressure shaft 111 and the low-pressure speed setpoint NIC 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 attempt 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 Ml to obtain a torque difference ATRQ, and a second sub-step of determining, by the first fuel regulation loop Bl, 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 according to 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 fuel control loop B2. Figure 7 shows seven additional fuel control loops B3 to B8, but the invention covers any number of fuel control loops, without being 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 as 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 in p: k • Transfer function in z: 1 f yl I kk Te Te^ / • • 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 of [Fig. 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 of [Fig. 7], the third fuel control loop B3 monitors a speed parameter NI of the low-pressure shaft 111 and ensures that it follows an acceleration trajectory for the high-pressure N1T speed. The third control loop B3 provides an output fuel command to maintain this low-pressure N1T speed acceleration trajectory.

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

[0077] In the example of [Fig. 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 N2Idle. The fifth fuel control loop B5 provides an output fuel command to maintain this idle speed criterion N2Idle. This fuel control loop B5 allows the gas generator 110 to be maintained in an idle state, thus enabling its economical use and prioritizing the use of the electric motor BP Ml via the torque control selection module 40. The gas generator 110 is therefore ready to supplement the power supplied by the electric motor BP Ml via the low-pressure torque control TRQBP in the event that the low-pressure torque control TRQBP encounters a limitation.

[0078] In the example of [Fig. 7], the sixth fuel control loop B6 monitors a static pressure parameter Ps3 measured at the outlet of the 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 of [Fig. 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 provides an output fuel command to maintain this speed threshold criterion N2Max.

[0080] In the example of [Fig. 7], the eighth fuel control loop B8 monitors a static pressure parameter Ps3 measured at the outlet of the 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 of [Fig. 7], the control system must manage eight different fuel commands, originating respectively 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 [Fig. 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 [Fig. 7], a "Max" operator allows the selection of the highest fuel command value from among the commands originating from loops B5, which seeks to maintain the high-pressure idle speed N2Idle, and B6, which seeks 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's torque deficit (M1), 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 (NIC), and those from the "Max" operators of loops B5 and B6. The output of the second "Max" operator is the input of a switch (15) 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 13 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 this switch 13 is the input of a switch 14 controlled by a deceleration indicator "Dec", this indicator allowing selection between the fuel command from switch 13 and the fuel command from the second loop B2 seeking to follow a high-pressure N2T acceleration trajectory. The output of this switch 14 is the input of switch 15 controlled by the low-pressure electric hybridization activation indicator GIDL, switch 15 also receiving as input the output of the second operator "Max".

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

[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 WFCMD command is thus obtained by the fuel command selection module 50. using a plurality of fuel regulation loops and a network of "Min", "Max" operators and switches. The final fuel flow control WFCMD will therefore either ensure the maintenance of the turbomachine 11 in operating condition, or supplement the power required by the TRQBP electric torque to ensure the control of the required thrust under responsive conditions.

[0086] When the turbomachine implementing the method 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 [Fig.3], the method 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 [Fig.8].

[0088] The selection module 60 shown in [Fig.8] is a TRQHP high pressure torque control selection module known to those skilled in the art, to which has been added a progressive reset loop comprising the delay operator Z 1 and the correction network RC4, in the input of a switch 17 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 a 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 provides a high-pressure torque command only when the WFCMD fuel command is limited within its operating range, i.e., for example, when the WFCMD fuel command reaches a maximum fuel level WFMax in the combustion chamber 103 and the low-pressure engine speed setpoint NIC is not reached. 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 a high-pressure torque command as output. 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 a zero value when the fuel difference is negative. Thus, step 24 includes a first sub-step of comparing the WFCMD fuel control to a maximum fuel WFMax to obtain a fuel difference AWF, and a second sub-step of determining, by the second HP torque control loop B10, a high pressure torque control as a function of the fuel difference AWF, by calculating in closed loop the high pressure torque required to bring the fuel difference AWF to a zero value.

[0092] The two high-pressure torque commands provided by the control loops B9 and B10 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-power, high-pressure torque limit injectable onto 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 a deceleration indicator allowing selection of 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 M1HP 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 command must not pass. The final command, TRQHP, 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 control The final high-pressure torque (TRQHP) will therefore either maintain the turbomachine 11 in operational 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 progressively reduced to zero during reactive conditions and is only activated outside of reactive conditions.

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

[0098] Figure 10 shows a schematic representation of the WF fuel control in 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 only 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 PW power of the turbomachine as a function of time, according to different scenarios. Curve D shows the power developed with the responsiveness assistance provided by the low-pressure torque TRQBP according to the invention, and curve E shows the power developed without the assistance of the invention. It is clear that the power developed 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, i.e., the power developed does not react quickly to changes in instructions when the conditions for reactivity are met.

Claims

1. Demands A computer-controlled method for controlling an aircraft turbomachine, the turbomachine being hybridized at least on a low-pressure body by including 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 (NIC) for the turbomachine and a current low-pressure operating speed (NI) value for the turbomachine, determine (21) that a low-pressure electric hybridization (GIDL) activation must take place when all of the following conditions are met: • The low-pressure operating setpoint (NIC) is below a predefined thrust threshold, • A difference between the low-pressure operating setpoint (NIC) of the turbomachine (11) and the current low-pressure operating value (NI) of the turbomachine (11) exceeds a predefined difference threshold for a predetermined duration and • The battery level is above a predefined battery threshold, determine (22) a low-pressure torque control (TRQBP) supplied to the low-pressure electric motor (Ml) by at least one 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 (NIC) and the current low-pressure speed (NI) value of the turbomachine, determine (23) a fuel flow control (WFCMD) in the combustion chamber by at least one first fuel control loop (Bl), comprising: • compare the low pressure torque control (TRQBP) to a maximum torque (TRQMAX) applicable to the low pressure electric motor (Ml) to obtain a torque difference, • determine, by the first fuel regulation loop (Bl), 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 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 a low-pressure electric hybridization (GIDL) activation must take place: - the low-pressure setpoint (NIC) is greater than the current low-pressure setpoint (NI), - an idle speed of the turbomachine (11) is reached, - the aircraft including the turbomachine (11) is on the ground, - the electric hybrid propulsion system is functional.

3. Method (20) according to any one of the preceding claims wherein the low pressure (NI) regime 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: - determining a first torque control by a first control loop as a function of the low-pressure turbomachine speed setpoint (NIC) to be achieved and the current low-pressure speed value (NI), - determining a second torque control by a second control loop as a function of an acceleration trajectory (N1T) of the low-pressure turbomachine speed to be followed and the current low-pressure speed value (NI), - 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. A 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: - determining, by means of a second fuel control 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), - determining, by means of a third fuel control loop (B3), a fuel flow control (WFCMD) in the combustion chamber (103) as a function of the current low-pressure speed value (NI) to follow a low-pressure speed acceleration trajectory (N1T), - determining, by means of a fourth fuel control loop (B4), a fuel flow control (WFCMD) in the combustion chamber (103) as a function of the current low-pressure speed value (NI) to follow the low-pressure speed setpoint (NIC),- maintain the gas generator (110) in an idle state (N2Idle) 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 (B 6) 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: • 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 rotating shaft (112), and • 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 (Ml) forming a torque injection device on the low pressure rotation shaft (111).

8. Aircraft comprising the turbomachine (11) according to claim 7. 27

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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