Method for controlling a turbomachine comprising an electric machine

Abstract

A method for controlling a turbomachine (T) comprising an electric machine, the control method having a first fuel regulation loop (B1) determining a fuel flow setpoint (WFcmd) and a second torque regulation loop (B2) determining an electrical torque setpoint (TRQcmd), the torque regulation loop (B2) being configured to determine the electrical torque setpoint (TRQcmd) from a determined transient torque setpoint (TRQtrans), a previous electrical torque setpoint (TRQcmd-1), and a transient phase indicator (TopTrans), the control setpoint (TRQcont) being determined from a previous control setpoint (TRQcont-1), a time constant (tau), and the previous electrical torque setpoint (TRQcmd-1) according to a first-order decreasing mathematical law. Abstract figure: Figure 7

Description

Title of the invention: Method for controlling a turbomachine comprising an electric machine Technical field

[0001] The present invention relates to an aircraft turbomachine, in particular, the control of a turbomachine to provide the desired thrust as a function of the position of the aircraft pilot's control lever.

[0002] 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 already in service, 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.

[0003] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using 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 on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] With reference to [Fig. 1], a turbomachine 100 of the twin-spool, turbofan-type aircraft engine is schematically represented. As is known, the turbomachine 100 comprises, from upstream to downstream in the direction of gas flow, a fan 110, a low-pressure compressor 111, and a high-pressure compressor 111. The system consists of a pressure 112, a combustion chamber 113 which receives a fuel flow setpoint WFcmd, a high-pressure turbine 114, a low-pressure turbine 115, and a primary exhaust nozzle 116. The low-pressure (LP) compressor 111 and the low-pressure turbine 115 are connected by a low-pressure shaft 121 and together form a low-pressure unit. The high-pressure (HP) compressor 112 and the high-pressure turbine 114 are connected by a high-pressure shaft 122 and together form a high-pressure unit. The blower 110, which is driven by the low-pressure shaft 121, compresses the intake air. This air is divided downstream of the blower 110 between a secondary airflow which is directed directly to a secondary nozzle (not shown) through which it is ejected, 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 116.As is known, to change the operating mode of the turbomachine 100, the aircraft pilot changes the position of a control lever which allows the fuel flow setpoint WFcmd to be changed in the combustion chamber 113.

[0007] The design of a turbomachine 100 requires taking into account a sufficient margin against the so-called surge phenomenon. This phenomenon, which results from an excessive impact of the airflow on the blades of one of the compressors, leads to significant and rapid fluctuations in pressure downstream of the compressor in question and can cause the combustion chamber 113 to shut down. It also generates significant shocks on the compressor blades and can thus lead to mechanical damage. It is therefore particularly important to avoid its occurrence. The operation of a compressor in use is generally represented by a diagram that expresses the pressure ratio obtained between the outlet and the inlet as a function of the air flow rate passing through it; this diagram is also parameterized according to the compressor's rotational speed.This diagram shows a pumping line, which represents the maximum compression ratio that must not be exceeded to avoid the risk of a pumping phenomenon. A line, known as the operating line, is defined by relating the compression ratios obtained as a function of the flow rate when the turbomachine 100 is in steady-state operation. The positioning of this operating line is left to the discretion of the turbomachine 100's designer, and the distance of this operating line from the pumping line represents the pumping margin. It should be noted that the compressor efficiency (the work done compressing the air, relative to the work done to rotate it) is, to a first approximation, better the closer one gets to the pumping line.Conversely, the accelerations requested by the pilot from a stabilized operation (transient phase) to obtain an increase in thrust, are translated at the compressor level by . an excursion from the operating point which takes place in the direction of the pumping line.

[0008] Indeed, an additional injection of fuel into the combustion chamber 113 causes a near-instantaneous increase in the compression ratio, even though the rotational speed does not have time to increase due to inertia. The enthalpy change imparted to the fluid by the combustion of the added fuel then generates an increase in the work supplied by each turbine and, consequently, an increase in the rotational speed of the corresponding body. This is reflected in the compressor diagram by a return of the operating point to the operating line when the speed stabilizes again, at an operating point that corresponds to a higher flow rate than the previous operating point.

[0009] The designer of a turbomachine 100 must therefore try to optimize the placement of the operating line by placing it as high as possible, so as to benefit from better yields for its compressors, while keeping a sufficient distance from the pumping line to allow safe accelerations.

[0010] To avoid any pumping phenomenon, a turbomachine 100 includes a control system implemented by an electronic unit. With reference to [Fig. 2], the control system comprises a stabilized management module 31, a transient intent detection module 32, a speed trajectory generation module 33, a transient management module 33', a selection module 34, an integration module 35, and a stop management module 36.

[0011] The transient management module 33' provides a correction quantity to the selection module 34 as a function of the difference between the NL regime of the turbomachine 100 and the trajectory from the regime trajectory generation module 33. The stabilized management module 31 provides a correction quantity to the selection module 34 as a function of the difference between the NL regime of the turbomachine 100 and the NLCons- setpoint regime. The NL regime can correspond to different types of regime, including, in particular, a fan regime, a pressure setpoint known by its English acronym EPR (Engine Pressure Ratio), a high pressure setpoint or other.

[0012] The NLCons setpoint regime is proportional to the position of the control lever operated by the aircraft pilot. Such a stabilized control module 31 is known to those skilled in the art and will not be described in further detail.

[0013] The transient intent detection module 32 is designed to detect a transient intent desired by the pilot. The transient intent detection module 32 determines a difference between the NL operating mode of the turbomachine 100 and the NLCons setpoint operating mode. When the control lever remains in a constant position and the stabilized management module 31 is activated, the actual operating mode The NL speed of the turbomachine 100 is stationary and equal to the setpoint speed NLCons. If the pilot moves the control lever, the setpoint speed NLCons changes instantaneously. Conversely, the NL speed does not change instantaneously due to the inertia of the turbomachine 100 and the stabilized control module 31. Thus, the transient intent detection module 32 detects a transient intent when the difference between the setpoint speed NLCons and the actual speed NL exceeds a predetermined threshold S2.

[0014] In the case of an acceleration request, if the engine speed deviation is greater than the predetermined threshold S2 (NLCons - NL > S2), an acceleration request is detected. Similarly, in the case of a deceleration, if the engine speed deviation is greater than the predetermined threshold S2 (NL - NLCons > S2), a deceleration request is detected. When a transient phase is detected, the transient intent detection module 32 generates an activation signal, which is transmitted to the engine speed trajectory generation module 33 and the selection module 34 as illustrated in [Fig. 2].

[0015] In the case of an acceleration request, the engine speed trajectory generation module 33 determines an engine speed setpoint for acceleration (acceleration trajectory). Similarly, in the case of deceleration, the engine speed trajectory generation module 33 determines an engine speed setpoint for deceleration (deceleration trajectory). Depending on the generated trajectory, the engine speed trajectory generation module 33 provides a correction value to the selection module 34.

[0016] Such a regime trajectory generation module 33 is known to the person skilled in the art, in particular from patent application US2013 / 0008171 and patent application FR2977638A1, and will not be presented in further detail.

[0017] In this example, the selection module 34 is configured to receive an activation signal from the transient intent detection module 32. The selection module 34 selects the correction value from the stabilized control module 31 if no activation signal is received, and selects the correction value from the transient control module 33' if an activation signal is received. Such a selection module 34 is known to those skilled in the art and will not be described in further detail. The selected correction value is provided to the integration module 35. The integration module 35 determines the fuel flow setpoint WFcmd by integrating the selected correction value.

[0018] The limit control module 36 limits the value of the fuel flow setpoint WFcmd determined by the integration module 35. As is known, the limit control module 36 implements a limit, referred to as the C / P limit, which is known to those skilled in the art, in order to protect the turbomachine against pumping. In this example, the limit control module 36 allows limit setpoints to be defined in acceleration and deceleration. Such limits are known to those skilled in the art and will not be described in further detail.

[0019] The engine speed trajectory generation module 33 and the stop management module 36 make it possible to define an acceleration trajectory which consequently limits the fuel flow setpoint WFcmd in order to prevent surge. Such a control system is known from patent application FR2977638A1 and will not be described in further detail. Incidentally, it is known to protect an engine against surge during transients by taking into account an acceleration setpoint during regulation (see, for example, US4543782 and US 2003 / 0094000).

[0020] In order to improve the response time of a turbomachine during a transient phase (acceleration, deceleration, etc.), it has been proposed to equip the turbomachine with an electric machine to provide additional electrical torque to increase the turbomachine's speed without causing a pumping effect. For this purpose, patent application WO2016 / 020618 discloses a turbomachine for aircraft comprising an electric machine for drawing power from the low-pressure shaft and injecting power onto the high-pressure shaft.

[0021] To reduce energy consumption related to the electric machine, it is known to operate the electric machine only during a transient phase. In practice, the electric machine is stopped at the end of the transient phase, resulting in a sudden loss of torque (step change) which is automatically compensated by a change in the fuel flow setpoint WFcmd.

[0022] This can lead to significant variations in operating conditions and repeated activations / deactivations of the electric machine, which can negatively impact the thrust and the lifespan of the electric machine.

[0023] The invention thus aims to eliminate at least some of these drawbacks by proposing a method for controlling a turbomachine that improves the management of the electric machine after a transient phase. PRESENTATION OF THE INVENTION

[0024] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to a method for controlling a turbomachine comprising a fan positioned upstream of a gas generator and defining 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, and a low-pressure turbine. said low-pressure turbine being connected to said low-pressure compressor by a low-pressure rotating shaft and said high-pressure turbine being connected to said high-pressure compressor by a high-pressure rotating shaft, the turbomachine being configured to be in a transient phase or in a stabilized phase, the turbomachine comprising an electric machine configured to apply a torque on the low-pressure rotating shaft or on the high-pressure rotating shaft during the transient phase, process in which a fuel flow setpoint in the combustion chamber and an electrical torque setpoint supplied to the electric machine are determined, the control process comprising a first fuel regulation loop determining the fuel flow setpoint and a second torque regulation loop determining the electrical torque setpoint.

[0025] The invention is remarkable in that: • The second torque control loop is configured to determine the electrical torque setpoint from a defined transient torque setpoint, a previous electrical torque setpoint, and a transient phase indicator. • The second torque regulation loop is configured, when the transient phase indicator is inactive, to determine that the electrical torque setpoint is equal to a control setpoint, the control setpoint being determined from a previous control setpoint, a time constant and the previous electrical torque setpoint according to a first-order decreasing mathematical law.

[0026] Thanks to the invention, the electrical torque setpoint is reduced rapidly and in a controlled manner while limiting steady-state error. This makes it possible to reduce electrical consumption after a transient phase while avoiding an abrupt reset that could lead to compensations by the first fuel regulation loop. The reset of the electrical torque setpoint is thus optimal.

[0027] Preferably, the mathematical law is equal to TRQcont = TRQcmd} - (TRQcont • In which • TRQcont is the control instruction • TRQcont-1 is the previous control instruction • tau is the time constant • TRQcmd-1 is the previous electrical torque setpoint • t is time.

[0028] Advantageously, the time constant tau is an image of the cancellation rate of the electric torque and can advantageously be parameterized.

[0029] Preferably, the torque control loop is configured to reset the control setpoint when the absolute value of the previous control torque setpoint is less than a predetermined shutdown constant. This prevents a very slow shutdown of the electrical supply when the electrical supply is low. Any unintended use of the electrical machine is thus avoided.

[0030] According to one aspect, the time constant governing the reset of the control setpoint is configurable. This allows the torque reset dynamics to be conveniently adjusted to match the dynamics of the first fuel regulation loop.

[0031] According to one aspect, the torque control loop is configured to receive transient indicators emitted by the fuel control loop and to determine the transient phase indicator from the transient indicators.

[0032] According to one aspect, the torque control loop is configured to add an aircraft power draw setpoint to the electrical torque setpoint. Thus, the electrical torque setpoint can take into account transient regimes as well as the aircraft's electrical power requirements.

[0033] The invention also relates to a computer program comprising instructions for executing the steps of a control process as previously described when said program is executed by a computer.

[0034] The invention also relates to an electronic control unit for a turbine machine comprising a memory including instructions from a computer program as previously described.

[0035] The invention also relates to a turbomachine comprising an electronic unit as previously described. PRESENTATION OF FIGURES

[0036] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0037] Fig. 1 is a schematic representation of a turbomachine according to the prior art.

[0038] [Fig.2] is a schematic representation of a fuel flow setpoint regulation system according to the prior art.

[0039] Fig. 3 is a schematic representation of a turbomachine according to one embodiment of the invention.

[0040] Fig. 4 is a schematic representation of a system for regulating a fuel flow setpoint and an electrical torque setpoint.

[0041] Fig. 5 is a schematic representation of an electrical torque setpoint control loop.

[0042] The [Fig.6] is a schematic representation of a transient determination block.

[0043] Fig. 7 is a schematic representation of a control module.

[0044] Figure 8 is a schematic representation of several mathematical laws of torque reduction to zero.

[0045] Fig. 9 is a schematic representation of torque reductions to zero in a first decreasing order for different time constants.

[0046] The [Fig. 10] is a schematic representation of the evolution of several physical quantities over time during changes in the regime of the turbomachine.

[0047] Fig. 11 is a schematic representation of a fuel flow setpoint regulation system and a torque setpoint, taking into account an electrical input from the aircraft in the regulation of the electrical torque setpoint.

[0048] Fig. 12 is a schematic representation of an electrical torque setpoint control loop taking into account the electrical input from the aircraft.

[0049] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0050] With reference to [Fig. 3], a turbomachine T of the twin-spool, twin-flow turbojet type for aircraft is schematically represented. As is known, the turbomachine T comprises, from upstream to downstream in the direction of gas flow, a fan 10, a low-pressure compressor 11, a high-pressure compressor 12, a combustion chamber 13 which receives a fuel flow setpoint WFcmd, a high-pressure turbine 14, a low-pressure turbine 15, and a primary exhaust nozzle 16. The low-pressure (LP) compressor 11 and the low-pressure turbine 15 are connected by a low-pressure shaft 21 and together form a low-pressure casing. The high-pressure (HP) compressor 12 and the high-pressure turbine 14 are connected by a high-pressure shaft 22 and together, with the combustion chamber 13, form a high-pressure casing. The blower 10, which is driven by the low-pressure shaft 21, compresses the ingested air.This air splits downstream of the blower 10 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 T, 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 16. In a known manner, to modify the operating regime of a turbomachine T, the aircraft pilot modifies the position of a control lever which allows the fuel flow setpoint WFcmd to be modified in the combustion chamber 13.

[0051] With reference to [Fig. 3], the turbomachine T further comprises an electric motor ME configured to provide additional torque to the low-pressure shaft 21 or the high-pressure shaft 22. The operation of the turbomachine T is controlled by an electronic unit 20 which obtains signals representing operating parameters of the turbomachine T, in particular a turbomachine T operating speed NL, to provide the fuel flow setpoint WFcmd and a torque setpoint TRQcmd to the electric motor ME. The NL operating speed can correspond to different types of operating speed, in particular, a fan operating speed, a pressure setpoint known by its English acronym EPR (Engine Pressure Ratio), a high-pressure operating speed setpoint, or other.

[0052] As illustrated in [Fig.4], the electronic unit 20 includes a control system comprising a first loop B1 for regulating the fuel flow setpoint WFcmd, hereafter referred to as "first fuel loop B1", and a second loop B2 for regulating the electrical torque setpoint TRQcmd, hereafter referred to as "second torque loop B2".

[0053] As illustrated in [Fig. 4], the first fuel loop B1 comprises: • A temperature input T2 • a turbomachine T operating temperature input NL • a setpoint input (NLCons) defined by the lever position control unit that can be operated by the aircraft pilot, • a fuel flow setpoint output WFcmd transmitted to the turbomachine T and • a plurality of output indicators: • an indicator of a TopAccel acceleration transient demand • an indicator of a TopDecel deceleration transient demand • an indicator of an acceleration limit TopButeeAccel defined by the saturation of the controller control by the acceleration limit C / P • an indicator of a deceleration stop (TopButeeDecel) defined by the saturation of the controller control by the extinction stop (C / P) • a target trajectory setting for acceleration NLTra-jAccCons • a target engine speed for deceleration NLTraj-DecelCons

[0054] Still with reference to [Fig.4], the second torque loop B2 receives as input all the output indicators generated by the first fuel loop B1, i.e. TopAccel, TopDecel, TopButeeAccel, TopButeeDecel, NLTrajAccCons, NLTrajDecelCons, as well as the NL speed input of the turbomachine T.

[0055] Thanks to this control system, the second torque loop B2 provides an adaptive torque setpoint TRQcmd based on the behavior of the first fuel loop B1, which retains priority. In this example, the first fuel loop B1 also includes a static pressure inlet in the combustion chamber PS3.

[0056] In detail, with reference to [Fig. 5], the second torque loop B2 includes a processing block B21 configured to determine a transient torque setpoint TRQtrans from the inputs NLTrajAccCons, NLTrajDecelCons, and the operating condition input NL of the turbomachine T. Such a processing block B21 is known from the prior art, in particular from patent application WO2016 / 020618. The transient torque setpoint TRQtrans allows the requirements of the turbomachine T to be met electrically during a transient operating condition.

[0057] The second torque loop B2 further includes a control module 3, schematically represented in [Fig.7], configured to determine the electrical torque setpoint TRQcmd from the transient torque setpoint TRQtrans, a prior electrical torque setpoint TRQcmd-1 and a transient phase indicator TopTrans.

[0058] In this example, the TopTrans transient phase indicator is active when the turbomachine T is in transient mode. For this purpose, as illustrated in [Fig. 5], the second torque loop B2 includes a transient determination block B22 to determine the TopTrans transient phase indicator. With reference to [Fig. 6], the TopTrans transient phase indicator is determined from the inputs TopAccel, TopDecel, TopButeeAccel, and TopButeeDecel. In particular, the TopTrans transient phase indicator is active: • when acceleration is requested and when the acceleration limit has already been reached (TopAccel and TopButeeAccel activated) • when a deceleration is requested and when the deceleration stop has already been reached (TopDecel and TopButeeDecel activated).

[0059] With reference to [Fig.7], the control module 3 includes a first AC switch configured to determine the electrical torque setpoint TRQcmd from the transient torque setpoint TRQtrans and a control setpoint TRQcont as a function of the transient phase indicator TopTrans.

[0060] With further reference to [Fig. 7], as long as the transient indicator TopTrans is active, the first switch CA determines that the electrical torque setpoint TRQcmd is equal to the transient torque setpoint TRQtrans. Indeed, when the turbomachine T is in transient operation, the electric motor ME provides a torque that meets the transient requirements of the turbomachine T.

[0061] When the TopTrans transient indicator is inactive, the first AC switch determines that the electrical torque setpoint TRQcmd is equal to the control setpoint TRQcont, which aims to reduce the electrical torque. The TRQcont control setpoint will now be displayed.

[0062] The control module 3 further includes a second CB switch configured to determine the control setpoint TRQcont from a prior electrical torque setpoint TRQcmd-1 and an intermediate control setpoint TRQcinter as a function of the transient phase indicator TopTrans.

[0063] The control module 3 further includes a third DC switch configured to determine the intermediate control setpoint TRQcinter from a reset setpoint and a reduced control setpoint TRQcontr based on a comparison indicator Icomp. The reduced control setpoint TRQcontr is determined from a previous electrical torque setpoint TRQcmd-1 and a previous control setpoint TRQcont-1.

[0064] In this example, the forward electrical torque setpoint TRQcmd-1 and the forward control setpoint TRQcont-1 are respectively determined by integrators intl, int2.

[0065] The different parameters will now be presented.

[0066] In this example, the reduced control setpoint TRQcontr is determined in a reduction loop 31 from the earlier control setpoint TRQcont-1, a time constant tau and the earlier electrical torque setpoint TRQcmd-1.

[0067] While the turbomachine T is in transient operation, the second switch CB determines that the control setpoint TRQcont is equal to the previous electrical torque setpoint TRQcmd-1. This control setpoint TRQcont is used by the reduction loop 31 to determine the reduced control setpoint TRQcontr. This advantageously synchronizes the reduction loop 31 with the electrical torque setpoint TRQcmd so that the value of the previous control setpoint TRQcont-1 is consistent with the values ​​of the electrical torque setpoint TRQcmd. When the turbomachine T returns to steady operation, the second switch CB sets the control setpoint TRQcont as the intermediate torque setpoint; the electrical torque at the start of the reset is thus the electrical torque at the end of the transient operation. The transition is advantageously seamless.

[0068] As illustrated in [Fig. 7], the previous control setpoint TRQcont-1 and a target value 0 (reset setpoint) are compared by an addl adder to determine a primary error epsl. The primary error epsl is then multiplied by the time constant tau in a multiplier block to obtain a secondary error eps2. The secondary error eps2 is then added to the previous electrical torque setpoint TRQcmd-1 via an add2 adder to determine the reduced control setpoint TRQcontr.

[0069] In other words, the reduction loop 31 allows the setpoint to be determined TRQcont control according to the following first-order decreasing mathematical law.

[0070] [Math.l] TRQcont = TRQcmd j - ^TRQcont

[0071] The absolute value of the primary error epsl is determined by an absolute value block abs and compared with a predetermined extinction constant e by a comparison block comp to determine a comparison indicator Icomp. In practice, the comparison indicator Icomp is active if the absolute value of the primary error epsl is less than the predetermined extinction constant e. The predetermined extinction constant e is configured to be close to 0 (reset setpoint) in order to force a reset of the electric torque when the electrical load is low. This prevents untimely use of the electric machine ME. It also prevents slow convergence to zero with a first-order mathematical law.

[0072] In this example, again with reference to [Fig. 7], when the control indicator Icomp is inactive, the third switch CC determines that the intermediate control setpoint TRQcinter is equal to the reduced control setpoint TRQcontr. This implementation advantageously reduces the output value of switch CB according to the first-order decreasing mathematical law as long as the control indicator Icomp is inactive. The turbomachine T can thus transition from one steady-state regime to another while conserving electrical resources.

[0073] Thanks to the invention, with reference to [Fig. 8], during a transition from a transient regime phase Rtrans to a stabilized regime phase Rstab, the control setpoint TRQcont is progressively reset to zero according to a first-order mathematical law RAZ2, which allows: • To limit the shocks on the ME electrical machine compared to a sudden reset according to a mathematical law defining a RAZ0 step and • To preserve electrical resources compared to a very gradual reset according to a mathematical law defining a ramp-down increasing RAZ1.

[0074] An abrupt reset by step RAZO also has the disadvantage of causing problems with the transitions between the transient operating phase Rtrans and the stabilized operating phase Rstab, and of untimely switching between these two phases. A very gradual reset using a decreasing ramp RAZ1 also has the disadvantage of causing a continuous error in the electrical torque.

[0075] Preferably, the time constant tau of the first-order mathematical law of the reduction loop 31 is parameterizable. With reference to [Fig. 9] representing several values ​​of the time constants taul, tau2, tau3, the speed of the response can thus be adjusted.

[0076] An example of implementation will be presented with reference to [Fig. 10] during an increase in engine speed decided by the aircraft pilot.

[0077] As illustrated in curve Cl, when a speed increase is requested, the low-pressure speed setpoint NLcons rises sharply at an initial instant t1, initiating a transient operating phase Rtrans. The low-pressure speed NL gradually follows the low-pressure speed setpoint NLcons to prevent any pumping of the turbomachine T. At a second instant t2, the low-pressure speed NL is close to the low-pressure speed setpoint NLcons, thus ending the transient operating phase Rtrans. The transient operating phase Rtrans is preceded by a first steady-state phase Rstab1 and followed by a second steady-state phase Rstab2.

[0078] As illustrated on curve C2, the high pressure torque setpoint NHcons is followed reactively by the synergistic cooperation between the fuel setpoint WFcmd (Curve C3) and the electrical torque setpoint TRQcmd (Curve C4).

[0079] As illustrated on curve C3, the fuel setpoint WFcmd increases progressively during a transient regime phase Rtrans.

[0080] During the transient operating phase Rtrans, as illustrated in curve C4, the transient indicator TopTrans is active and the electrical torque setpoint TRQcmd corresponds to the transient torque setpoint TRQtrans. The reduction loop 31 is disconnected from the output of the second torque loop B2. In this example, the second control loop B2 gradually increases the torque of the electric machine on the high-pressure shaft 22. This results in a gradual increase in the rotational speed of the high-pressure shaft 22.

[0081] After the end of the transient regime phase Rtrans, the transient indicator TopTrans is inactive (the acceleration transient indicator TopAccel is lowered) and the torque setpoint TRQcmd is gradually reset to zero according to a first-order mathematical law. This allows the first fuel loop Bl, which has Having regained control over the fuel setpoint WFcmd, the rotational speed of the low-pressure shaft 21 is regulated without disturbance. When the primary deviation epsl is small with respect to the predetermined extinction constant e, the electrical torque setpoint TRQcmd is reset directly to zero to conserve electrical resources.

[0082] According to one aspect of the invention, with reference to [Fig. 1 1], the second torque loop B2 also receives as input an aircraft take-off command TRQaero to meet the electrical needs of the aircraft, in particular, to enable electrical generation.

[0083] To this end, as illustrated in [Fig. 12], the second torque loop B2 further includes an adder 4 which adds an aircraft power draw setpoint TRQaero to the electrical torque setpoint TRQcmd determined by the control module 3. Thus, advantageously, only the portion of the electrical torque setpoint TRQcmd related to the transient regime is reset. The electric machine ME can continue to supply electrical power to the aircraft.

Claims

Claims

1. Method for controlling a turbomachine (T) comprising a fan (10) 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 (11), a high pressure compressor (12), a combustion chamber (13), a high pressure turbine (14) and a low pressure turbine (15), said low pressure turbine (15) being connected to said low pressure compressor (11) by a low pressure rotation shaft (21) and said high pressure turbine (14) being connected to said high pressure compressor (12) by a high pressure rotation shaft (22), the turbomachine (T) being configured to be in a transient phase or in a stabilized phase,the turbomachine comprising an electric machine (ME) configured to apply a torque to the low pressure rotation shaft (21) or to the high pressure rotation shaft (22) during the transient phase, method in which a fuel flow setpoint (WFcmd) in the combustion chamber (13) and an electric torque setpoint (TRQcmd) supplied to the electric machine (ME) are determined, the control method comprising a first fuel control loop (B1) determining the fuel flow setpoint (WFcmd) and a second torque control loop (B2) determining the electric torque setpoint (TRQcmd), • the second torque control loop (B2) being configured to determine the electrical torque setpoint (TRQcmd) from a determined transient torque setpoint (TRQtrans), a previous electrical torque setpoint (TRQcmd-1) and a transient phase indicator (TopTrans), • the second torque control loop (B2) being configured, when the transient phase indicator (TopTrans) is inactive, to determine that the electrical torque setpoint (TRQcmd) is equal to a control setpoint (TRQcont), the control setpoint (TRQcont) being determined from a previous control setpoint (TRQcont-1), a time constant (tau) and the previous electrical torque setpoint (TRQcmd-1) according to a mathematical law decreasing theme of the first order.

2. Method for controlling a turbomachine (T) according to claim 1, in which the mathematical law is equal to TRQcont = TRQcmd 1 - (TRQcont • In which • TRQcont is the control setpoint • TRQcont-1 is the previous control setpoint • tau is the time constant • TRQcmd-1 is the previous electric torque setpoint • t is the time.

3. Method for controlling a turbomachine (T) according to one of claims 1 to 2, in which the torque control loop (B2) is configured to reset the control setpoint (TRQcont) to zero when the absolute value of the previous control torque setpoint (TRQcont-1) is less than a predetermined extinction constant (e).

4. Method for controlling a turbomachine (T) according to one of claims 1 to 3, in which the time constant (tau) governing the resetting of the control setpoint (TRQcont) is configurable.

5. Method for controlling a turbomachine (T) according to one of claims 1 to 4, in which the torque control loop (B2) is configured to receive transient indicators (TopAccel, TopBu-teeAccel, TopDecel, TopButeeDecel) emitted by the fuel control loop (B1) and to determine the transient phase indicator (TopTrans) from the transient indicators (TopAccel, TopBu-teeAccel, TopDecel, TopButeeDecel).

6. Method for controlling a turbomachine (T) according to one of claims 1 to 5, in which the torque control loop (B2) is configured to add an aircraft power extraction setpoint (TRQaéro) to the electric torque setpoint (TRQcmd).

7. Computer program comprising instructions for executing the steps of a control method according to one of claims 1 to 6 when said program is executed by a computer.

8. Electronic control unit (20) for a turbomachine (T) comprising a memory including instructions of a computer program according to claim 7.

9. Turbomachine (T) comprising an electronic unit (20) according to claim 8.

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