FR3151721A1 - Method for controlling a hybrid engine that attenuates vibrations as a function of power, engine for implementing this method and aircraft equipped therewith - Google Patents

Abstract

Method for controlling a motorization (M) comprising a turbomachine (TM) coupled to an electric machine (MEL), and an electronic control unit (20) of the motorization connected to a power converter (12) to control the electric machine selectively in motor mode and in generator mode from a reference torque filtered in a self-adaptive manner to exclude therefrom a range of excitation frequencies of at least one torsion mode of the motorization, as a function of a mechanical power on an output shaft of the electric machine. Corresponding motorization and aircraft comprising such a motorization. FIGURE OF THE ABSTRACT: Fig. 2

Description

Method for controlling a hybrid engine that attenuates vibrations as a function of power, engine for implementing this method and aircraft equipped therewith

The present invention relates to the field of electrical machines and in particular those used in hybrid motorization systems combining an electric machine and a thermal machine.

BACKGROUND OF THE INVENTION

Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft as well as those in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

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.

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 and, more generally, reduce the environmental footprint of its activity.

This ongoing research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and the lighter on-board equipment, and the development of the use of electrical technologies to provide propulsion.

As part of this work on aircraft motorization, a hybrid thermal/electric motorization was proposed.

• une turbomachine ayant une ligne d’arbres parcourant un étage haute pression et un étage basse pression,
• une machine électrique ayant un arbre relié à la ligne d’arbres de la turbomachine pour fonctionner soit comme moteur en fournissant un couple mécanique à la ligne d’arbres de la turbomachine, soit en générateur en étant entraîné par la ligne d’arbres de la turbomachine,
• un onduleur de pilotage de la machine électrique dans les deux modes de fonctionnement précités, l’onduleur étant commandé par une unité électronique de commande de la motorisation,
• un circuit d’alimentation continue, par exemple à batteries, relié à l’onduleur et agencé pour être réversible de manière à sélectivement alimenter la machine électrique lorsque la machine électrique fonctionne en moteur ou recevoir l’énergie électrique fournie par la machine électrique lorsque la machine électrique fonctionne en générateur.

This hybrid engine includes:

• a turbomachine having a line of shafts running through a high pressure stage and a low pressure stage,
• an electric machine having a shaft connected to the turbomachine shaft line to operate either as a motor by providing mechanical torque to the turbomachine shaft line, or as a generator by being driven by the turbomachine shaft line,
• an inverter for controlling the electric machine in the two aforementioned operating modes, the inverter being controlled by an electronic motor control unit,
• a continuous power supply circuit, for example with batteries, connected to the inverter and arranged to be reversible so as to selectively supply the electric machine when the electric machine operates as a motor or receive the electrical energy supplied by the electric machine when the electric machine operates as a generator.

The electrical system comprising the electrical machine, the inverter and the power supply circuit must be sized to provide the electrical power necessary to inject power into the turbomachine, in particular to assist in starting the turbomachine and limit its fuel consumption during certain phases of flight, and to guarantee sufficient power to supply the aircraft's electrical equipment when the electrical machine is operating as a generator.

The electrical system must also be reliable, robust and designed so as not to disrupt the operation of the turbomachine.

The Applicant has noted that the electric machine, and in particular the electromagnetic torque present in the electric machine, may include a dynamic component (oscillation around the continuous torque) capable of generating an excitation of certain torsion modes of the drive train of the motorization. This excitation results in a torque oscillation which, depending on its frequency, may excite the torsional vibration modes of the shafts of the motorization. The excitation of these torsion modes causes a high increase in vibration levels on the shafts of the motorization (this increase is commonly called overvoltage), phase shifts, as well as damping phenomena at low frequency as well as at high frequency. This may result in vibration fatigue of the drive train which may lead, in the worst case, to a breakage of the drive train. Such a breakage may be catastrophic if it concerns the turbomachine.

SUBJECT OF THE INVENTION

The invention aims in particular to improve these electrical systems, particularly with regard to the control of the vibration phenomena which they can generate.

For this purpose, the invention provides a method for controlling a motorization comprising a turbomachine having at least a first shaft, an electric machine having a second shaft coupled to the first shaft, an electronic control unit for the motorization, a power converter for controlling the electric machine selectively in motor mode and in generator mode from a reference torque provided by the electronic control unit as a function of a mechanical power of the second shaft in operation, and a reversible power supply circuit connected to the power converter for selectively powering the electric machine in motor mode or being powered by the electric machine in generator mode. The method comprises the steps of:

- previously identify excitation frequency ranges of at least one torsion mode of the first shaft by the electric machine as a function of mechanical powers of the second shaft;

- and, when the motor is operating, filter the reference torque at the electronic control unit by applying a filter whose cut-off frequency range is adjusted to exclude at least one excitation frequency range identified as corresponding to the mechanical power of the second shaft.

Thus, filtering the reference torque (such as a torque setpoint or command) makes it possible to avoid the excitation frequencies of all or part of the torsion modes. As it appears that the excitation frequency range of the torsion modes is not constant and depends in particular on the load caused on the motorization by the equipment to which it is connected (see the ), the cut-off frequency of the filter used in the invention is adapted according to the mechanical power loading the electric machine. This ensures that the reference torque does not cause excitation of the torsion modes, whatever the operating conditions of the motorization.

The invention also relates to a motorization comprising a thermal machine having at least a first shaft, an electric machine having a second shaft coupled to the first shaft, an electronic control unit for the motorization, a power converter for controlling the electric machine selectively in motor mode and in generator mode from a reference torque provided by the electronic control unit, and a reversible power supply circuit connected to the inverter to selectively power the electric machine in motor mode or to be powered by the electric machine in generator mode. The electronic control unit comprises a member for determining a mechanical power of the second shaft and a self-adaptive filtering member for the reference torque, the self-adaptive filtering member having a determined cut-off frequency range, as a function of the determined mechanical power, to correspond to an excitation frequency range of at least one torsion mode of the first shaft.

• l’unité électronique de commande comprend une table mettant en relation des plages de fréquences de coupure de l’organe de filtrage auto-adaptatif et des puissances mécaniques, chaque plage de fréquences de coupure de l’organe de filtrage auto-adaptatif étant sensiblement égale à la plage de fréquence d’excitation d’au moins un mode de torsion du premier arbre pour la puissance mécanique correspondante.
• l’unité électronique de commande est reliée à un dispositif d’acquisition d’une vitesse du deuxième arbre et à un couplemètre de mesure d’un couple du deuxième arbre pour déterminer la puissance mécanique du deuxième arbre.
• l’unité électronique de commande est agencée pour mettre en œuvre une stratégie d’hybridation par laquelle elle détermine à chaque instant :
  • si la machine électrique doit fonctionner en générateur ou en moteur ;
  • une première puissance mécanique que la machine électrique doit prélever sur la turbomachine lorsqu’elle fonctionne en générateur et une deuxième puissance mécanique que la machine électrique doit fournir à la turbomachine lorsqu’elle fonctionne en moteur ;
  • le couple de référence qui correspond à la première puissance mécanique ou à la deuxième puissance mécanique ainsi déterminée selon que la machine électrique fonctionne en générateur ou en moteur et qui est transmis à l’organe de filtrage.
• le couple de référence filtré est transmis à une boucle de courant pilotant le convertisseur de puissance et, de préférence, la boucle de courant comprend un dispositif de modulation de largeur d’impulsion à vecteur spatial.
• la turbomachine comprend deux premiers arbres appartenant pour l’un à un étage haute pression et pour l’autre à un étage basse pression de la turbomachine et, de préférence, la motorisation comprend deux machines électriques, à savoir une première dont le deuxième arbre est couplé au premier arbre de l’étage haute pression et une deuxième dont le deuxième arbre est couplé au premier arbre de l’étage basse pression.

According to optional features, used individually or in whole or in part in combination:

• the electronic control unit comprises a table relating cut-off frequency ranges of the self-adaptive filtering member and mechanical powers, each cut-off frequency range of the self-adaptive filtering member being substantially equal to the excitation frequency range of at least one torsion mode of the first shaft for the corresponding mechanical power.
• the electronic control unit is connected to a device for acquiring a speed of the second shaft and to a torque meter for measuring a torque of the second shaft to determine the mechanical power of the second shaft.
• the electronic control unit is designed to implement a hybridization strategy by which it determines at each moment:
  • whether the electric machine is to operate as a generator or a motor;
  • a first mechanical power that the electric machine must draw from the turbomachine when it operates as a generator and a second mechanical power that the electric machine must supply to the turbomachine when it operates as a motor;
  • the reference torque which corresponds to the first mechanical power or to the second mechanical power thus determined depending on whether the electric machine operates as a generator or as a motor and which is transmitted to the filtering device.
• the filtered reference torque is transmitted to a current loop driving the power converter and, preferably, the current loop comprises a space vector pulse width modulation device.
• the turbomachine comprises two first shafts, one belonging to a high pressure stage and the other to a low pressure stage of the turbomachine and, preferably, the motorization comprises two electric machines, namely a first one whose second shaft is coupled to the first shaft of the high pressure stage and a second one whose second shaft is coupled to the first shaft of the low pressure stage.

The invention finally relates to a vehicle and more particularly an aircraft provided with such a motorization.

Other characteristics and advantages of the invention will emerge from reading the following description of particular and non-limiting embodiments of the invention.

Reference will be made to the attached drawings, including:

there is a schematic view of an aircraft according to the invention;

there is a schematic view of a motorization of this aircraft, according to a particular embodiment of the invention;

[Fig. 3 Figure 3 is a more detailed schematic view of this motorization;

there is a schematic view of the motorization according to a variant of this particular embodiment;

there is a graph showing the evolution of the excitation frequency of the first torsion mode as a function of the power supplied by the electric machine;

there is a Bode diagram representing a frequency analysis of the mechanical transmission chain of the thermal machine.

DETAILED DESCRIPTION OF THE INVENTION

With reference to figures 1 and 2, the invention is described in application to a hybrid engine M of an aircraft A. The hybrid engine M here comprises a turbomachine TM and an electric machine MEL.

The TM turbomachine - here more particularly a turbojet, a turboprop or a turboshaft engine - is known in itself and will only be briefly described here. The TM turbomachine comprises a high pressure stage HP and a low pressure stage LP. The high pressure stage HP comprises a shaft coupled via a set of gears (not shown) to a shaft of the low pressure stage LP forming a kinematic chain comprising a line of shafts L.

The MEL electric machine comprises an electric motor 10 having an output shaft 11 coupled via a set of gears G to one and/or the other of the shafts of the turbomachine TM. The electric motor 10 is here a permanent magnet motor.

The electric motor 10 has electromagnetic windings connected to power electronics comprising a direct/alternating power converter such as here an inverter 12 arranged to operate the electric motor 10 either in motor mode or in generator mode. The inverter 12 is itself connected to a power supply circuit 13 which is connected to the electrical circuit E of the aircraft A comprising batteries and is arranged to be reversible so as to selectively power the electric motor 10 from the batteries to drive the output shaft 11 in rotation when the electric motor 10 of the electric machine MEL is in motor mode, or to be powered by the electric machine MEL when the electric motor 10 of the electric machine MEL is in generator mode, in particular to recharge the batteries and/or to directly power electrical equipment connected to the electrical circuit E of the aircraft A. The electric machine MEL, and in particular the electric motor 10, the inverter 12 and the power supply circuit 13 are known per se.

• d’une consigne de courant Iq* fournie par la logique d’hybridation 23,
• de valeurs de courant (ia, ib, ic) des phases du moteur électrique 10 fournies par un dispositif d’acquisition de courants 24, ici à effet Hall, relié à l’unité de commande 20,
• d’une position angulaire θméca et d’une vitesse angulaire Ωméca de l’arbre de sortie 11 du moteur électrique 10 fournies par un résolveur 25 relié à l’unité de commande 20. Les données angulaires Ωméca et θméca sont issues classiquement du traitement des signaux du résolveur 25.

The motorization M comprises a control unit 20 arranged to control the turbomachine TM and the electric machine MEL. The control unit 20 is an electronic unit (of the integrated circuit, FPGA, ASIC, microcontroller type, etc.) comprising for example one or more processors and one or more memories containing one or more computer programs for controlling the motorization M. The control unit 20 here comprises a control module 21 of the turbomachine TM and a control module 22 of the electric machine MEL and implements a hybridization logic symbolized at 23. The control module 21 of the turbomachine TM is of the FADEC or EEC type known per se. The control module 22 of the electric machine MEL comprises a current loop controlling the inverter 12 according to:

• of a current instruction Iq* provided by the hybridization logic 23,
• of current values (ia, ib, ic) of the phases of the electric motor 10 provided by a current acquisition device 24, here with Hall effect, connected to the control unit 20,
• of an angular position θmeca and an angular speed Ωmeca of the output shaft 11 of the electric motor 10 provided by a resolver 25 connected to the control unit 20. The angular data Ωmeca and θmeca are conventionally derived from the processing of the signals from the resolver 25.

• les courants iα et iβ qui sont les courants d’axe α et β issus de la transformée de Clarke recevant en entrée les courants de phase ia, ib, ic ;
• les courants id et iq qui sont les courants d’axe d et q issus de la transformée de Park recevant en entrée les courants iα et iβ ;
• les consignes de courant Id* et Iq* qui sont les consignes de courant d’axes d et q.

The control of the MEL electric machine is carried out in the control module 22 using:

• the currents iα and iβ which are the α and β axis currents resulting from the Clarke transform receiving as input the phase currents ia, ib, ic;
• the currents id and iq which are the d and q axis currents from the Park transform receiving as input the currents iα and iβ;
• the current instructions Id* and Iq* which are the current instructions of axes d and q.

• les tensions Vd** et Vq** qui sont les tensions de référence d’axes d et q issues des correcteurs PI recevant en entrée respectivement les signaux Id*-id et Iq*-iq ;
• les tensions Vd* et Vq* qui sont les tensions de référence d’axes d et q issues du découplage des tensions Vd** et Vq** en fonction des courants iq et id et de la vitesse angulaire Ωméca ;
• les tensions Vα* et Vβ* qui sont les tensions de référence d’axes α et β issues de la transformée inverse de Park recevant en entrée les tensions Vd* et Vq*.

Typically, the current loop of the control module 22 also involves:

• the voltages Vd** and Vq** which are the d and q axis reference voltages from the PI correctors receiving the Id*-id and Iq*-iq signals as input respectively;
• the voltages Vd* and Vq* which are the d and q axis reference voltages resulting from the decoupling of the voltages Vd** and Vq** as a function of the currents iq and id and the angular speed Ωmeca;
• the voltages Vα* and Vβ* which are the reference voltages of axes α and β resulting from the inverse Park transform receiving as input the voltages Vd* and Vq*.

The Park transforms are performed also using θelec which is the electrical angular position of the electric motor 10 and which is equal to the angular position θmeca multiplied by the number of pole pairs of the electric motor 10 (block noted θcorrection on the ).

The voltages Vα* and Vβ* supply a space vector pulse width modulation device SVM providing duty cycle ratios Duty 1, Duty 2, Duty 3 for controlling the inverter 12.

A reference voltage Vdc provided by the power supply circuit 13 supplies the PI correctors, the space vector pulse width modulation device SVM and the inverter 12.

• si la machine électrique MEL doit fonctionner en générateur ou en moteur ;
• la puissance mécanique que la machine électrique MEL doit prélever sur la turbomachine PM lorsqu’elle fonctionne en générateur et la puissance mécanique que la machine électrique MEL doit fournir à la turbomachine PM lorsqu’elle fonctionne en moteur ;
• une consigne de couple ou couple de référence C*_avant correspondant à la puissance mécanique déterminée à l’étape précédente.

The hybridization logic 23 is arranged to implement a hybridization strategy (block 231) by which it determines at each instant, as a function of the orders of the pilot of the aircraft, the flight phase and the signals coming to it from the sensors of the aircraft:

• whether the MEL electric machine is to operate as a generator or a motor;
• the mechanical power that the MEL electric machine must draw from the PM turbomachine when it operates as a generator and the mechanical power that the MEL electric machine must supply to the PM turbomachine when it operates as a motor;
• a torque instruction or reference torque C*_avant corresponding to the mechanical power determined in the previous step.

The hybridization logic 23 receives as input an angular speed Ω of the output shaft 11 from the resolver 25 and a torque C of the output shaft 11 of the electric motor 10 provided by a torque meter 26 connected to the control unit 20. The hybridization logic 23 is arranged to calculate, from these two values, a mechanical power measured at the output shaft 11 (block 232) and to determine, as a function of the mechanical power measured at the output shaft 11, a range of cut-off frequencies fc corresponding to excitation frequencies of torsion modes of the shaft line L (block 233).

The determination of the cut-off frequency range as a function of the mechanical power measured at the output shaft 11 is for example obtained by using a two-dimensional table (Look-up-Table type) which relates the cut-off frequencies to power values. Such a table is for example obtained by determining the excitation frequencies of the torsion modes of the drive train of the motorization as a function of the power either by simulation or by experiment from tests of a motorization provided with accelerometers and a torque meter to search for the frequencies which amplify the torque oscillations on the drive train of the motorization M.

• l’harmonique 1 produit par un balourd mécanique ;
• l’harmonique 2 produit par un défaut de coaxialité entre le rotor et le stator ;
• l’harmonique dont le rang correspond au produit du nombre de pôles et du nombre de phases du moteur électrique 11 et produite par une oscillation de couple ;
• l’harmonique dont le rang correspond au produit du nombre de dents et du nombre d’encoches et produite par des efforts de denture statorique.

We are particularly interested in the harmonics produced by the MEL electric machine and whose frequencies are close to the torsion modes of the TM turbomachine. Some harmonics, in particular those of low order, have more energy than others and, if they have frequencies close to the torsion modes, can generate overvoltages (indeed, the higher the order of the harmonic, the lower the energy levels of the latter). In addition, low-frequency modes generate high vibration displacements. The harmonics likely to generate high overvoltages include:

• harmonic 1 produced by a mechanical imbalance;
• harmonic 2 produced by a coaxiality defect between the rotor and the stator;
• the harmonic whose rank corresponds to the product of the number of poles and the number of phases of the electric motor 11 and produced by a torque oscillation;
• the harmonic whose rank corresponds to the product of the number of teeth and the number of notches and produced by stator toothing forces.

For example, a Campbell diagram of the TM turbomachine is used to determine the natural frequencies of the components of the TM turbomachine as a function of the rotation speed. On such a diagram, oblique lines are drawn which are the natural frequencies of the different components of the engine, horizontal lines corresponding to the frequencies of the torsion modes and vertical lines corresponding to the minimum speed of the TM turbomachine and to the maximum speed of the TM turbomachine. The risk zones correspond to the intersection of the natural frequency lines with the lines of the frequencies of the torsion modes obtained by a frequency analysis by a Bode diagram to identify the frequency(ies) most at risk. On the , we observe a maximum value of the torsion mode at a frequency of approximately 29 Hz with an amplification of approximately 50 dB. This therefore clearly constitutes the risk zone where the harmonics carrying the most energy (such as torque oscillation) must be controlled in order to minimize their impact on the overvoltage generated. We therefore seek to control the most energetic harmonics that may cross the frequency(ies) at risk.

• une composante naturelle d’oscillation de couple qui est due à la saillance des pôles du moteur électrique 10 et qui apparaît indépendamment du fonctionnement de l’électronique de puissance ;
• une composante liée au pilotage du moteur électrique 10 qui engendre une oscillation de couple via l’harmonique 6 ;
• une composante liée aux temps morts de l’onduleur qui engendre également une oscillation de couple via l’harmonique 6.

Three components of excitation are taken into account here:

• a natural component of torque oscillation which is due to the salience of the poles of the electric motor 10 and which appears independently of the operation of the power electronics;
• a component linked to the control of the electric motor 10 which generates a torque oscillation via harmonic 6;
• a component linked to the inverter dead times which also generates a torque oscillation via harmonic 6.

The hybridization logic 23 also comprises a self-adaptive filter 234, of the band-stop type, receiving as input the torque setpoint C*_before and providing as output a filtered torque setpoint C*_after. The self-adaptive filter 234 has a cut-off frequency, or rather a range of cut-off frequencies fc, which is adjusted according to the load power of the output shaft 11 to filter the torque setpoint C*_before so as to exclude the excitation frequency ranges fc of the torsion modes.

The filtered torque setpoint C*_after is then transformed into a current setpoint (block 235) to form the current setpoint Iq* used at the input of the current loop of the control module 22.

The torque and speed measurements are preferably carried out on the output shaft 11 upstream of the gear set coupling the output shaft 11 and the shaft line of the turbomachine TM. For the speed measurement, it is possible to use the derivative of the mechanical position angle θmeca given by the resolver 25. Alternatively, it is possible to use the measurement at the output of the gear set because it is difficult to carry out a measurement at the coupling point: the measurement at the output of the gear set makes it possible to go back to the torque and speed of the output shaft 11 by knowing the gear ratio of the gear set (calculated from the number of teeth or the diameter of each pinion).

In the context of the invention, these measurements are used to calculate in real time and during operation of the motorization M, the mechanical power. The mechanical power serves as input in the table of block 233 and the output of block 233 is the cut-off frequency of filter 234 which is therefore also provided in real time.

The 234 filter has more precisely the following FT form:

• est la fréquence de coupure, c’est-à-dire la fréquence centrale rejetée ;
• est la largeur de la bande rejetée ;
• s est la variable de Laplace.

with the following parameters:

• is the cutoff frequency, i.e. the rejected center frequency;
• is the width of the rejected band;
• s is the Laplace variable.

The filter thus defines a frequency range which must be attenuated between two limits (two cut-off frequencies given by the width of the K band around the central cut-off frequency).

It is understood that the parameters of filter 234 (cut-off frequency and bandwidth) are updated in real time according to the mechanical power determined at each moment according to a given periodicity.

The method of the invention thus comprises a prior step of identifying the excitation frequency ranges of at least one torsion mode of the shaft line of the motorization M and steps carried out by the control unit 20 during operation of the motorization M, namely: determining a mechanical power of the output shaft 11 and filtering the torque setpoint to exclude the excitation frequency range corresponding to the determined mechanical power.

Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

In particular, the motorization may have a different structure than that described.

• une unique machine électrique MEL BP, couplée à l’arbre BP de l’étage basse pression BP de la turbomachine, ou
• une unique machine électrique MEL HP, couplée à l’arbre HP de l’étage haute pression HP de la turbomachine, ou
• une machine électrique MEL BP couplée à l’arbre BP de l’étage basse pression BP de la turbomachine et une machine électrique MEL HP couplée à l’arbre HP de l’étage haute pression HP de la turbomachine comme dans le deuxième mode de réalisation de la . Dans ce cas, le filtrage peut être réalisé pour une seule des machines électriques ou les deux machines électriques.

The motorization can include:

• a single MEL BP electric machine, coupled to the BP shaft of the low pressure BP stage of the turbomachine, or
• a single MEL HP electric machine, coupled to the HP shaft of the HP high pressure stage of the turbomachine, or
• an MEL BP electric machine coupled to the BP shaft of the low pressure BP stage of the turbomachine and an MEL HP electric machine coupled to the HP shaft of the high pressure HP stage of the turbomachine as in the second embodiment of the . In this case, filtering can be performed for only one of the electrical machines or both electrical machines.

The table can be defined to have constant interval input values (e.g. 5, 10, 15, 20) or not (e.g. 3, 5, 7, 10, 15, 20, 25… if the excitation frequency varies significantly between 3 and 10). The table can be replaced by a law matching power and frequency to avoid.

The cut-off frequency range of the filtering device as a function of the mechanical power can be determined to avoid excitation of one or more torsion modes of the shaft line depending on the impact of these torsion modes on the reliability of the motorization M.

The electric motor 11 can be of any type, including a wound rotor motor, a permanent magnet motor or an asynchronous motor.

The invention can be used with any turbomachine and is not limited to use of this engine on an aircraft or vehicle.

Claims (10)

Method for controlling a motorization (M) comprising a turbomachine (TM) having at least a first shaft (L), an electric machine (MEL) having a second shaft (11) coupled to the first shaft, an electronic control unit (20) for controlling the motorization, a power converter (12) for controlling the electric machine selectively in motor mode and in generator mode from a reference torque provided by the electronic control unit as a function of a mechanical power of the second shaft in operation, and a reversible power supply circuit (13) connected to the power converter to selectively power the electric machine in motor mode or to be powered by the electric machine in generator mode, characterized in that the method comprises the steps of:
previously identifying excitation frequency ranges of at least one torsion mode of the first shaft by the electric machine as a function of mechanical powers of the second shaft;
and, in operation of the motorization in operation, filtering the reference torque at the level of the electronic control unit by applying a filter whose cut-off frequency range is adjusted to exclude at least one excitation frequency range identified as corresponding to the mechanical power of the second shaft. Motorization (M) comprising a turbomachine (TM) having at least a first shaft (L), an electric machine (MEL) having a second shaft (11) coupled to the first shaft, an electronic control unit (20) for controlling the motorization, a power converter (12) for controlling the electric machine selectively in motor mode and in generator mode from a reference torque provided by the electronic control unit, and a reversible power supply circuit (13) connected to the power converter to selectively power the electric machine in motor mode or to be powered by the electric machine in generator mode, characterized in that the electronic control unit (20) comprises a member for determining a mechanical power of the second shaft and a self-adaptive filtering member (234) for the reference torque, the self-adaptive filtering member having a determined cut-off frequency range, as a function of the determined mechanical power of the second shaft, to correspond to a range of excitation frequencies of at least one torsion mode of the first shaft. Motorization (M) according to claim 2, in which the electronic control unit (20) comprises a table relating cut-off frequency ranges of the self-adaptive filtering member (234) and mechanical powers, each cut-off frequency range of the self-adaptive filtering member (234) being substantially equal to the excitation frequency range of at least one torsion mode of the first shaft for the corresponding mechanical power. Motorization (M) according to claim 2 or 3, in which the electronic control unit (20) is connected to a device for acquiring a speed of the second shaft (11) and to a torque meter for measuring a torque of the second shaft to determine the mechanical power of the second shaft. Motorization (M) according to any one of claims 2 to 4, in which the electronic control unit (20) is arranged to implement a hybridization strategy (231) by which it determines at each instant:

• whether the electrical machine (MEL) is to operate as a generator or a motor;
• a first mechanical power that the electric machine must draw from the turbomachine (TM) when it operates as a generator and a second mechanical power that the electric machine must supply to the turbomachine when it operates as a motor;
• the reference torque (C*_avant) which corresponds to the first mechanical power or to the second mechanical power thus determined depending on whether the electric machine operates as a generator or as a motor and which is transmitted to the filtering member (234).

Motorization (M) according to any one of claims 2 to 5, in which the filtered reference torque is transmitted to a current loop controlling the power converter (12). Motorization (M) according to the preceding claim, in which the current loop comprises a space vector pulse width modulation device. Motorization (M) according to any one of claims 2 to 7, in which the turbomachine comprises two first shafts, one belonging to a high pressure (HP) stage and the other to a low pressure (LP) stage of the turbomachine. Motorization (M) according to the preceding claim, comprising two electrical machines (MEL), namely a first (MEL HP) whose second shaft is coupled to the first shaft of the high pressure stage (HP) and a second (MEL BP) whose second shaft is coupled to the first shaft of the low pressure stage (BP). Aircraft comprising a motorization (M) according to any one of claims 2 to 9.