FR3098663A1 - ARCHITECTURE FOR TRANSFERRING REGENERATED ELECTRICAL ENERGY IN AN AIRCRAFT AND PROCESS FOR TRANSFERING REGENERATED ELECTRIC ENERGY IN SUCH ARCHITECTURE - Google Patents

Abstract

The invention relates to an architecture (20) for transferring regenerated electrical energy in an aircraft, comprising: an electrical generator (26), a first voltage converter (30) arranged at the output of the electrical generator, a communication bus ( 32) at direct current and at high voltage supplied by the first voltage converter, an electric power motor (36) comprising a second voltage converter (34) connected to the communication bus, energy storage means (42) electrical connected to the communication bus, a braking resistor (46), and a supervisor (48) configured to implement a control-command law of voltage converters for, depending on the state of components of the architecture, distributing the regenerated electrical energy to one or more components of the architecture, the components of the architecture being the storage means, the electric generator, the motor and the braking resistor. Figure for the abstract: Figure 2

Description

ARCHITECTURE FOR TRANSFERRING REGENERATED ELECTRIC ENERGY INTO AN AIRCRAFT AND METHOD FOR TRANSFERRING REGENERATED ELECTRIC ENERGY IN SUCH AN ARCHITECTURE

Technical field of the invention

The present invention relates to the field of the dissipation of regenerated energy in an aircraft by machines or electric actuators, during deceleration or braking phases.

In particular, electrical machines or actuators can send electrical deceleration or braking energy back to the electrical network of the aircraft, in which this electrical energy must be dissipated.

This invention is part of a complete electrical chain, from electrical generation to electric motors driving propellers intended to provide thrust.

In particular, the invention consists in the production of a specific architecture for processing regenerated energy with a specific control-command law for the various components of the architecture. An architecture defines an electrical installation.

Technical background

In a known manner, in order to dissipate the regenerated energy in an architecture of an aircraft, it is possible to use ohmic conductors, that is to say resistors, for example made of ceramic. However, this solution has many drawbacks.

Indeed, the architectures evolve in a severe aeronautical environment. Thus, these classic energy dissipation solutions based on resistors impose a large volume, hence a considerable associated weight, as well as a rise in temperature within the architecture.

There are solutions to overcome these drawbacks, in particular regenerated energy processing architectures.

Patent application FR-A1-2 967 847 relates to a process and an architecture for processing the regenerated electrical energy of an aircraft. This solution proposes to send the energy back to the electrical generator of the architecture to convert this energy into mechanical energy.

As shown in Figures 1a and 1b, the architecture comprises a reversible electric generator 1, driven by a thermal machine 2, for example an auxiliary power unit (APU, acronym for the English expression "Auxiliary Power Unit"), and capable of delivering an alternating voltage; electric actuators 10a-10d and a multi-channel voltage converter circuit 4 with multiple links La-Ld. The actuators 10a-10d, here motors, can operate in motor mode (the arrows F _M representing the operation of the actuators 10a-10d in motor mode), or in generator mode (the arrows F _R representing the operation of the actuators 10a-10d in generator mode).

The voltage converter circuit 4 includes alternating voltage rectifier means 3, 11 coming from the generator 1 and from the power converters 5a-5d arranged on the multiple links La-Ld and able to drive as many electric actuators 10a-10d. In particular, the AC voltage rectifying means 11 are reversible.

Contactors 6a-6d are arranged on the links La-Ld, between the power converters 5a-5d and the corresponding actuators 10a-10d and make it possible to configure each link according to the motor or generator operating modes of the actuators 10a-10d.

The voltage converter circuit 4 also comprises means 7 for the reverse transmission of electrical energy (the arrows F _R and F _D representing the reverse transmission of electrical energy) applied to the generator 1 operating in motor mode.

A method and a system have also been implemented to improve the management of the electrical charge regeneration of an aircraft, and more specifically to return regenerated energy to the distribution bus of an aircraft, with a view to reuse.

This solution proposes to return the regenerated energy to a bidirectional power supply bus to supply other actuation loads and/or auxiliary loads, as well as to return the energy to the electrical generator of the architecture so as to convert this energy into mechanical energy and dissipate the prevailing energy into a rotating machine of the aircraft.

The architecture includes a main motor providing power to mechanical power loads, a generator for converting mechanical power from the main motor into electrical power, a reversible converter for converting power between the generator and a bus power supply.

The power bus is a bidirectional bus, and is intended to supply one of the types of actuation and/or auxiliary loads, and to receive energy from the actuation loads when they are regenerated by the auxiliary loads .

Thus, these architectures propose to dissipate the regenerated electrical energy by transforming it into mechanical energy supplied to other consumers, to use the regenerated electrical energy for auxiliary loads and/or other actuation loads, and to limit the mechanical energy brought to the architecture by dynamic braking of the motor.

However, these solutions do not make it possible to recover and store electrical energy.

Another solution proposes to reduce the clipping function of the direct current bus (DC, acronym for the English expression "Direct Current") during regeneration cycles, by storing the energy in super-capacitors. This is carried out on a direct current and high voltage (HVDC, acronym for the English expression “High Voltage Direct Current”) communication bus, with an alternating current bus (AC, acronym for the English expression “High Voltage Direct Current”) as a source. Alternative Current”) and as a load for electric motors.

Different mono-objective control laws, i.e. regulation of a single system parameter, and multi-objective control laws, i.e. regulation of several system parameters, are described and compared. The multi-objective control law controls the voltage and the current in the super-capacitors and their state of charge, in order to optimize the use of the latter.

This solution proposes to use a multi-objective control law to drive a power converter connected to super capacitors, with the aim of reducing the energy conversion chain, and to use these super capacitors to store energy that can be redistributed or absorbed quickly during transients.

However, this solution does not make it possible to store the regenerated electrical energy in a sustainable manner with a view to reusing it later.

The object of the invention is to propose a solution making it possible to remedy at least some of these drawbacks.

In particular, the invention aims to eliminate the drawbacks posed by the usual energy dissipation solutions based on resistors, as well as to recover and store electrical energy.

The invention proposes to return the electrical energy either to the electrical generator of the architecture to convert this electrical energy into mechanical energy, or to one or more batteries to store the electrical energy in a more sustainable manner than in super-capacitors ; and in certain operating cases, to dissipate the unconverted or unstored surplus in an electric power motor and also in one or more braking resistors, in particular of low volume.

• un générateur électrique réversible entraîné par un arbre mécanique et apte à délivrer une tension alternative,
• un premier convertisseur de tension quatre quadrants configuré pour convertir une tension alternative en tension continue, dit convertisseur AC-DC, et inversement, le premier convertisseur de tension étant agencé en sortie du générateur électrique,
• un bus de communication à courant continu et à haute tension, dit bus HVDC, alimenté par le premier convertisseur de tension,
• un moteur électrique de puissance réversible comprenant un deuxième convertisseur de tension apte à fonctionner sur quatre quadrants et configuré pour convertir une tension continue en tension alternative, et inversement, dit convertisseur DC-AC, le deuxième convertisseur de tension étant connecté au bus HVDC,
• des moyens de stockage d’énergie électrique connectés au bus HVDC,
• au moins une résistance de freinage, et
• un superviseur configuré pour implémenter une loi de contrôle-commande des premier et deuxième convertisseurs de tension pour, en fonction de l’état d’organes de l’architecture, distribuer l’énergie électrique régénérée vers un ou plusieurs des organes de l’architecture, les organes de l’architecture étant lesdits moyens de stockage, le générateur électrique, ledit moteur et la résistance de freinage.

More specifically, the invention relates to an architecture for transferring regenerated electrical energy in an aircraft, comprising:

• a reversible electric generator driven by a mechanical shaft and capable of delivering an alternating voltage,
• a first four-quadrant voltage converter configured to convert an alternating voltage into direct voltage, called an AC-DC converter, and vice versa, the first voltage converter being arranged at the output of the electric generator,
• a direct current and high voltage communication bus, called HVDC bus, powered by the first voltage converter,
• a reversible power electric motor comprising a second voltage converter able to operate on four quadrants and configured to convert a direct voltage into alternating voltage, and vice versa, called DC-AC converter, the second voltage converter being connected to the HVDC bus,
• electrical energy storage means connected to the HVDC bus,
• at least one braking resistor, and
• a supervisor configured to implement a control-command law for the first and second voltage converters in order, depending on the state of the components of the architecture, to distribute the regenerated electrical energy to one or more of the components of the architecture , the members of the architecture being said storage means, the electric generator, said motor and the braking resistor.

The architecture according to the invention comprises new organs compared to the solutions of the prior art and differs from these existing architectures in particular by a specific control-command law for these organs.

This makes it possible to optimize the electrical energy, and therefore to limit the external energy brought to the architecture, and to secure the architecture against overvoltages, whether transient or more durable.

The control-command law makes it possible, depending on the state of the architecture, to choose which organ of the architecture must be used for the dissipation of electrical energy during the regeneration phase.

• les moyens de stockage lorsque la tension du bus HVDC est comprise entre une première et une deuxième tension prédéterminée, la deuxième tension prédéterminée étant supérieure à la première tension prédéterminée,
• le générateur électrique lorsque la tension du bus HVDC est comprise entre la deuxième et une troisième tension prédéterminée, la troisième tension prédéterminée étant supérieure à la deuxième tension prédéterminée,
• le moteur lorsque la tension du bus HVDC est supérieure à la troisième tension prédéterminée et lorsque la température du moteur est inférieure à une température prédéterminée,
• la résistance de freinage lorsque la température du moteur est supérieure à la température prédéterminée.

In particular, the control-command law can be implemented in the supervisor to distribute the regenerated electrical energy to:

• the storage means when the voltage of the HVDC bus is between a first and a second predetermined voltage, the second predetermined voltage being greater than the first predetermined voltage,
• the electric generator when the voltage of the HVDC bus is between the second and a third predetermined voltage, the third predetermined voltage being higher than the second predetermined voltage,
• the motor when the HVDC bus voltage is higher than the third predetermined voltage and when the motor temperature is lower than a predetermined temperature,
• the braking resistor when the motor temperature is higher than the predetermined temperature.

The storage means may comprise one or a plurality of batteries, for example of the Lithium-ion type, and/or one or a plurality of super-capacitors, and/or one or a plurality of ultra-capacitors. In particular, the storage means may take the form of an array of batteries.

The architecture may include one or a plurality of braking resistors.

Preferably, the braking resistor(s) are small size and low power resistors. In particular, the size and volume of the braking resistor(s) can be reduced by 50% with the invention compared to the prior art.

For safety reasons, each braking resistor has a braking arm configured to dissipate electrical energy during transients or during potential overvoltages on the HVDC bus.

According to the invention, the electric generator can operate in generator mode and produce electrical energy from the mechanical energy transmitted by the mechanical shaft; or operate in motor mode and produce mechanical energy from the regenerated electrical energy. The reversible electric generator is thus a motor-generator.

The electrical generator may be a permanent magnet generator.

Alternatively, the electrical generator may be a separately excited synchronous generator.

Alternatively, the electric generator can be a variable reluctance generator with separate excitation or self-excited.

The electric generator may be capable of delivering a three-phase alternating voltage.

The first AC-DC voltage converter can be an active rectifier, or a rectifier-inverter.

Advantageously, the invention therefore allows electrical energy to be stored in storage means, which may take the form of a network of batteries. This stored electrical energy can be used later to supply starters, or to limit the external energy supplied, so as to optimize the electrical energy consumed. This allows a reduction in the dimensions of the electric generator compared to an architecture according to the prior art.

The invention also allows dissipation of residual or transient electrical energy in a braking resistor, in particular of small size and low power. This makes it possible to secure the architecture against transient or longer-lasting overvoltages. In addition, a small size and low power braking resistor does not pose a heat dissipation problem in the architecture.

The invention also allows dissipation of electrical energy of the copper loss and iron loss type in the motor stator, by controlling the direct axis current and the quadrature.

According to the invention, the HVDC bus is fast and robust between each voltage converter controlling the storage and dissipation of electrical energy.

According to the invention, the control-command law manages the voltage converters according to the voltage of the HVDC bus and the state of the various storage and dissipation organs of the regenerated electrical energy.

This architecture also allows a reduction in the weight of the electrical energy dissipation function. Indeed, during power demand peaks, the storage means supply power to the actuation chain. Thus, the electric generator can provide only average power. The use of the storage means as a source of storage of regenerated electrical energy for the actuation chain therefore makes it possible to reduce the size of the electrical generator.

The invention also allows control, by the first AC-DC voltage converter, of the active and reactive power supplied by the electric generator. This voltage converter also allows operation in motor mode of the electric generator for reinjection of the regenerated electrical energy, by controlling the angle between the current vector and the flux in the air gap.

In fact, when the voltage applied to the terminal of the electric generator is greater than the sum of the back-electromotive force voltage and the armature reactance of the stator, the electric generator operates in motor mode, i.e. injects a positive torque on the mechanical shaft.

In the case of regeneration, the voltage of the HVDC bus increases and becomes higher than this threshold voltage at the terminal of the electric generator. In order to control the angle of the current vector flowing in the electric generator, the inductance of the electric generator is used as the inductance of the first voltage converter. In particular, each phase of the first voltage converter acts as a step-down device, with the inductance smoothing the current.

This advantageously allows the integration of the power electronics in the electric generator, the inductors being bulky and expensive elements.

The architecture according to the invention can also comprise a third bidirectional voltage converter configured to convert a DC voltage into a DC voltage, called a DC-DC converter. The third voltage converter can be arranged between the storage means and the HVDC bus.

The supervisor can be configured to implement a control-command law for the first, second and third voltage converters in order, depending on the state of the components of the architecture, to distribute the regenerated electrical energy to one or more of the components of architecture.

In particular, when the HVDC bus has a fixed direct current voltage, the DC-DC converter is necessary to make it possible to regulate the variable voltage of the storage means. In this case, it is possible to feed an ATA-24 electrical network. Electrical energy can be consumed directly by power consumers on the HVDC bus.

When the HVDC bus has a floating voltage, the storage means can be connected directly to the HVDC bus, without the intermediary of the DC-DC converter.

The architecture according to the invention can also comprise a high-bandwidth communication bus connecting the supervisor and the first and second voltage converters. In other words, a robust, high-bandwidth communication bus enables communication between the voltage converters and the supervisor, the supervisor supplying the setpoints according to the state of the various components, that is to say according to voltage, current, or state of charge. The supervisor can be configured to control the voltage of this communication bus by inverse voltage droop.

The architecture according to the invention can also comprise a thermal machine, for example a gas turbine, which comprises the mechanical shaft.

The invention also relates to a method for transferring regenerated electrical energy in an architecture according to the invention, in which in nominal operating mode, the electrical generator is driven by the mechanical shaft and supplies power to the motor via the first and second voltage converters and the HVDC bus, and characterized in that in the braking or deceleration phase, a regeneration of electrical energy is produced, and in that the regenerated electrical energy is transmitted, depending on the state of the components of the architecture, to a component of the architecture according to the control-command law of the first and second voltage converters.

In the method according to the invention, when the voltage of the HVDC bus is between the first and the second predetermined voltage, the regenerated electrical energy can be transmitted to the storage means.

In the method according to the invention, when the voltage of the HVDC bus is between the second and the third predetermined voltage, the regenerated electrical energy can be transmitted to the electrical generator.

In the method according to the invention, when the voltage of the HVDC bus is higher than the third predetermined voltage and when the temperature of the motor is lower than the predetermined temperature, the regenerated electrical energy can be transmitted to the motor.

In the method according to the invention, when the temperature of the motor is higher than the predetermined temperature, the regenerated electrical energy can be transmitted to the braking resistor.

The method according to the invention may comprise the use of the inductance of the electric generator as the inductance of the first voltage converter when the regenerated electric energy is transmitted to the electric generator.

The invention thus allows reverse transmission of electrical energy to the electrical generator, in motor mode, via the inductance of the electrical generator which is used as inductance of the first AC-DC voltage converter.

In the method according to the invention, in the acceleration phase, when the voltage of the HVDC bus is greater than a fourth predetermined voltage, the electrical generator and the storage means supply electrical energy to the motor, in particular via the first converter voltage and the HVDC bus.

In the method according to the invention, in the acceleration phase, when the voltage of the HVDC bus is lower than the fourth predetermined voltage, the electric generator supplies electrical energy to the motor, in particular via the first voltage converter and the bus HVDC, and recharges the storage means to a fifth predetermined voltage, the fifth predetermined voltage being greater than the fourth predetermined voltage.

In the method according to the invention, in the acceleration phase, when the voltage of the HVDC bus is greater than the fifth predetermined voltage, the electric generator supplies electrical energy to the motor, in particular via the first voltage converter and the bus HVDC.

Brief description of figures

The present invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description of a non-limiting example which follows, with reference to the appended drawings in which:

FIG. 1a schematically represents an architecture for processing the regenerated electrical energy of an aircraft according to the prior art,

FIG. 1b schematically represents another embodiment of the architecture of FIG. 1a,

FIG. 2 schematically represents an architecture for transferring regenerated electrical energy in an aircraft according to the invention,

FIG. 3 is a flowchart of the implementation of the control-command law by the supervisor of the architecture according to the invention, in the event of absorption of electrical energy,

FIG. 4 is a graph illustrating the evolution of the voltage of the HVDC bus of the architecture according to the invention as a function of time during the implementation of the control-command law by the supervisor, in the event of absorption electrical energy,

FIG. 5 is a graph illustrating the evolution of the regenerated electrical power of the assembly consisting of the motor and the propeller of the architecture according to the invention as a function of time during the implementation of the control law - control by the supervisor, in the event of absorption of electrical energy,

FIG. 6 is a graph illustrating the evolution of the speed of the rotational speed of the motor shaft of the architecture according to the invention as a function of time during the implementation of the control-command law by the supervisor, in the event of absorption of electrical energy,

FIG. 7 is a flowchart of the implementation of the control-command law by the supervisor of the architecture according to the invention, in the event of a demand for electrical energy,

FIG. 8 is a graph illustrating the evolution of the voltage of the HVDC bus of the architecture according to the invention as a function of time during the implementation of the control-command law by the supervisor, in the event of a request for electrical energy, and

FIG. 9 is a graph illustrating the evolution of the power of the electric power motor of the architecture according to the invention as a function of time during the implementation of the control-command law by the supervisor, in the event of electrical energy demand.

The elements having the same functions in the different implementations have the same references in the figures.

Detailed description of the invention

FIG. 2 represents an architecture 20 for transferring regenerated electrical energy in an aircraft according to the invention.

A thermal machine 22, for example a gas turbine, comprises a mechanical shaft 24, which drives an electric generator 26.

The electric generator 26 is reversible. Thus, the electric generator 26 can operate in generator mode and produce electrical energy from the mechanical energy transmitted by the mechanical shaft 24, or operate in motor mode and produce mechanical energy from the regenerated electrical energy.

The electric generator 26 is capable of delivering an alternating voltage, for example three-phase. In Figure 2, the three phases 28a, 28b, 28c of the electric generator 26 are represented.

The electric generator 26 can be a permanent magnet generator, or a synchronous generator with separate excitation, or a variable reluctance generator with separate excitation, or a self-excited variable reluctance generator, or any other type of electric generator.

A four-quadrant AC-DC voltage converter 30, that is to say reversible in current and in voltage, is arranged at the output of the electric generator 26. This voltage converter 30 is configured to convert an alternating voltage into direct voltage, and vice versa.

The AC-DC voltage converter 30 can be an active rectifier, or a rectifier-inverter.

The 30 AC-DC voltage converter supplies an HVDC bus 32

The HVDC bus 32 is connected to a DC-AC voltage converter 34 of an electric power motor 36 capable of operating on four quadrants, that is to say capable of being reversible in voltage and current.

The 34 DC-AC voltage converter is reversible, i.e. it is configured to convert direct voltage to alternating voltage, and vice versa.

Motor 36 is a rotating machine which drives a propeller 38, via a drive shaft 40.

Storage means 42 of electrical energy are connected to the HVDC bus 32.

The storage means 42 can comprise super-capacitors, ultra-capacitors and/or batteries, in particular of the Lithium-ion type, and have the form of a network of batteries.

The batteries can be connected to the HVDC 32 bus via a bidirectional, i.e. reversible, 44 DC-DC voltage converter. The DC-DC voltage converter 44 is configured to convert DC voltage to DC voltage.

The DC-DC voltage converter 44 makes it possible to regulate the variable voltage of the batteries, in particular when the HVDC bus 32 has a fixed direct current voltage.

Alternatively, the batteries can be directly connected to the HVDC bus 32, in particular when the HVDC bus 32 has a floating voltage.

One or more braking resistors 46 are connected to the HVDC bus 32. Preferably, the braking resistors 46 are of low volume and low power.

A braking resistor 46 comprises a braking arm configured to dissipate electrical energy during transients or during overvoltages on the HVDC bus 32.

A supervisor 48 is connected to the voltage converters 30, 34, 44 via a high-bandwidth communication bus 50, i.e. a robust, high-bandwidth communication bus. The communication bus 50 can have a bandwidth of at least 5 Mb per second, the regeneration response time being of the order of a hundred microseconds. Such a communication bus 50 makes it possible to transfer the commands with the least possible latency time. The communication bus 50 can be a CAN bus.

The supervisor 48 is configured to implement a control-command law for the voltage converters 30, 34, 44 to distribute the electrical energy regenerated in the architecture to at least one among the storage means 42, the electrical generator 26 , the motor 36 and the braking resistor(s) 46.

This control-command law is implemented according to the state of the components of the architecture, so as to optimize the transfer of electrical energy in terms of efficiency and oversizing.

This control-command law is based on the control and measurements of the various state variables of the components of the architecture so as to know the state of the energy conversion chain of the architecture, i.e. i.e. current, voltage, power, speed, or even torque.

The state variables can be the temperature of the electric generator 26, the temperature of the motor 36, the temperature of the voltage converters 30, 34, 44, the state of charge of the storage means 42, the torque exerted on the shaft of the electric generator 26, and the voltage/current pairs for each member of the architecture.

The supervisor 48 controls the distribution of the regeneration energy in the storage and dissipation organs of the architecture.

In particular, each voltage converter 30, 34, 44 sends to the supervisor 48 its status and its monitoring signal. The supervisor 48 then sends each voltage converter 30, 34, 44 a checkpoint indicating to which component of the architecture the regenerated electrical energy must be sent.

The supervisor 48 can also manage power peaks.

The supervisor 48 gives priority for the storage or the management of the storage of electrical energy, then for the reinjection or the reuse of the electrical energy, and finally for the dissipation of electrical energy to a particular organ of the architecture, depending on the voltage of the HVDC bus 32, the regenerated electrical energy, as well as the state of the organs.

During a major regeneration, the battery or batteries can be recharged as a priority, instead of requesting the transfer of electrical energy into mechanical energy by the electrical generator 26.

When the battery or batteries are charged to a predetermined level, as the voltage of the HVDC bus 32 increases, the regenerated electrical energy can be fed back to the electric generator shaft 26.

If the temperature of the motor 36, or if another constraint of the electric generator is reached, the motor 36, then the braking resistor(s) 46 can dissipate the remainder of the regenerated electrical energy.

In particular, the battery or batteries are charged or discharged as a priority so as to maintain the level of charge of the latter within a certain range comprised between 60% and 70% of the maximum charge corresponding respectively to two voltage values of the HVDC bus 32 This range of between 60% and 70% of the maximum charge of the battery(ies) 42 is a compromise between the size of the battery(ies) 42, their lifetime and the number of recharges.

The high charge current level during the regeneration phase advantageously makes it possible to improve the lifetime of the lithium-ion type battery or batteries.

In particular, the depth of discharge is preferably not greater than 50% so as to avoid premature degradation of batteries of the Lithium-ion type.

This advantageously allows a certain charge capacity of the batteries so as to be able to meet a need for additional power requested by the engine, but also a certain charge reserve of the batteries so as to be able to authorize recovery of regenerated energy.

In Figure 2, arrow A represents the electrical energy regenerated from propeller 38.

The electrical energy is regenerated towards the storage means 42 when the voltage of the HVDC bus 32 is between a first and a second predetermined voltage, the second predetermined voltage being greater than the first predetermined voltage. As represented in FIG. 2, the arrow A1 illustrates the regeneration of electrical energy towards the storage means 42, that is to say the charging of the batteries.

The electrical energy is regenerated to the electrical generator 26 when the voltage of the HVDC bus 32 is between the second and a third predetermined voltage, the third predetermined voltage being higher than the second predetermined voltage. In FIG. 2, the arrow A2 illustrates the regeneration of electrical energy towards the electrical generator 26, that is to say the transformation of electrical energy into mechanical energy.

Electric power is regenerated to motor 36 when the voltage of HVDC bus 32 is above the third predetermined voltage and when the temperature of motor 36 is below a predetermined temperature. As shown in Figure 2, arrow A3 illustrates the regeneration of electrical energy to motor 36, i.e. the dissipation of regenerated electrical energy in motor 36.

Electrical energy is regenerated to the braking resistor(s) 46 when the temperature of the motor 36 is above the predetermined temperature. In FIG. 2, the arrow A4 illustrates the regeneration of electrical energy towards the braking resistor(s) 46, that is to say the dissipation of the regenerated electrical energy in the braking resistor(s) 46.

The invention thus proposes to return the electrical energy either to the electrical generator 26 to convert this electrical energy into mechanical energy, or to the battery or batteries to store the electrical energy; and in certain operating cases, to dissipate the unconverted or unstored surplus in the motor 36 and also in the braking resistor(s) 46.

FIG. 3 represents the control-command law managed by the supervisor 48, in the event of absorption of electrical energy. FIGS. 4 to 6 represent respectively the evolution of the voltage V _B of the HVDC bus 32, of the regenerated electrical power P of the assembly consisting of the motor 36 and the propeller 38 and of the speed of rotation v of the motor shaft 36 as a function of time t.

During the detection of a regeneration phase ϕ _R (step E1), that is to say during the detection of a negative torque, there is an increase in the voltage of the HVDC bus 32. It is then determined whether the voltage of the HVDC bus 32 is between the first voltage threshold V1 corresponding to the first predetermined voltage and the second voltage threshold V2 corresponding to the second predetermined voltage (step E2).

In this case, the battery or batteries are recharged from the voltage threshold V1 to the voltage threshold V2 (step E3). The increase in the voltage of the HVDC bus 32 is limited by the charge rate of the battery or batteries.

Then, when it is determined that the voltage of the HVDC bus 32 exceeds the voltage threshold V2, but remains below a third voltage threshold V3 corresponding to the third predetermined voltage (step E4), the voltage converter 30 is used as inverter to reinject the electric energy on the shaft of the electric generator 26 (step E5). The storage means 42 are then no longer charged, in order to preserve their longevity.

Next, it is determined whether the voltage of the HVDC bus 32 exceeds the voltage threshold V3 (step E6). In this case, and as long as the temperature of the motor 36 is lower than a predetermined temperature, the electric energy is regenerated towards the electric motor 26 (step E7). In particular, the voltage converter 34 of the motor 36 controls the flux regulator to increase the copper losses and the iron losses of the motor 36, as long as the temperature of the motor 36 allows it. The electrical power absorbed by the motor 36 depends on the speed of the shaft of the motor 36: the lower the speed of the shaft of the motor 36, the lower the electrical power absorbed.

Next, it is determined whether the engine temperature exceeds the predetermined temperature (step E8). In this case, the electrical energy is regenerated towards the braking resistor(s) 46 (step E9). In other words, if the temperature of the motor 36 exceeds the predetermined temperature, the dissipation is carried out in the brake resistor(s) 46.

As represented in FIG. 5, apart from a regeneration phase ϕ _R , or between two regeneration phases ϕ _R represented by the period T _R , the power P regenerated by the motor 36 and the propeller 38 is substantially equal to a power noted Pmean. At the start of a regeneration phase ϕ _R , the power P regenerated by the motor 36 and the propeller 38 increases up to a maximum power denoted Pmax. During the regeneration phase ϕ _R , the power P regenerated by the motor 36 and the propeller 38 decreases linearly from the power Pmax to the power Pmoy.

The regenerated power P of the assembly consisting of the motor 36 and the propeller 38 depends on the inertia and the deceleration requirement.

As represented in FIG. 6, before a regeneration phase ϕ _R , the speed of rotation v of the shaft of the motor 36 increases up to a speed of rotation vmax. During a regeneration phase ϕ _R , the speed of rotation v of the shaft of motor 36 decreases linearly from the speed of rotation vmax to a speed of rotation vmin, after the regeneration phase ϕ _R . Between two regeneration phases, represented by the period T _R , the speed of rotation v of the shaft of the motor 36 decreases linearly to the speed of rotation vmin, then remains substantially constant and equal to the speed of rotation vmin. During the following regeneration phase ϕ _R , the speed of rotation v of the shaft of motor 36 increases from the speed of rotation vmin to the speed of rotation vmax, after the regeneration phase ϕ _R .

FIG. 7 represents the control-command law managed by the supervisor 48, in the event of a demand for electrical energy. FIGS. 8 and 9 represent respectively the evolution of the voltage V _B of the HVDC bus 32 and of the electrical power P _M of the motor 36 as a function of time t.

During the detection of an acceleration phase, and therefore of power consumption, of the motor 36 (step E10), that is to say during the detection of a positive torque, there is a decrease in the voltage of the HVDC bus 32. It is then determined whether the voltage of the HVDC bus 32 is greater than a fourth voltage threshold V4 corresponding to a fourth predetermined voltage (step E11).

In this case, the electric generator 26 and the battery or batteries supply electrical energy to the motor 36 (step E12), in particular via the voltage converter 30 and the HVDC bus 32. In particular, the battery or batteries supply the power in transient in order to relieve the electric generator 26. The batteries are discharged to supply the motor 36. The reduction in the voltage of the HVDC bus 32 is limited by the rate of charge of the battery or batteries.

Then, it is determined if the voltage of the HVDC bus 32 becomes lower than the voltage threshold V4 (step E13), and in this case, the electric generator 26 supplies electric energy to the motor 36, in particular via the voltage converter 30 and the HVDC bus 32, and recharges the batteries up to a fifth voltage threshold V5 corresponding to a fifth predetermined voltage (step E14). As shown in Figure 8, the voltage threshold V5 is greater than the voltage threshold V4, Thus, the voltage of the HVDC bus 32 is monitored, and as soon as it reaches the voltage threshold V4, the current is no longer supplied by the battery or batteries to avoid an excessive discharge of the latter, but only by the electric generator 26 via the voltage converter 30. Once the demand for power has been supplied, the electric generator 26 recharges the battery or batteries up to at the voltage threshold V5. This voltage threshold V5 allows the battery(ies) to be recharged sufficiently to subsequently supply additional energy to a future power demand and to accept an absorption of a following regeneration.

Next, it is determined whether the voltage of the HVDC bus 32 is greater than the voltage threshold V5 (step E15). When the voltage of the HVDC bus 32 is greater than voltage V5 alone, the electric generator 26 supplies electrical energy to the motor 36 (step E16), in particular via the voltage converter 30 and the HVDC bus 32.

As shown in Figures 8 and 9, when the voltage of the HVDC bus 32 is greater than the voltage threshold V5, the electric generator 26 supplies electrical energy to the motor 36 during an acceleration phase. Therefore, the voltage of the HVDC bus 32 decreases, and the power of the motor 36 increases.

Then, when the voltage of the HVDC bus 32 is between the voltage thresholds V4 and V5, the battery or batteries discharge to supply additional power to the motor 36 and relieve the electric generator 26. As a result, the bus voltage HVDC 32 decreases, and the power of motor 36 increases until it reaches the required acceleration power Pacc.

Then, as the power demand is satisfied, the generator recharges the battery or batteries up to the voltage threshold V5.

The invention also relates to a method for transferring regenerated electrical energy into an architecture 20 as described previously.

In nominal operating mode, the electric generator 26 is driven by the mechanical shaft 24 of the thermal machine 2 and supplies power to the motor 36 via the voltage converters 30, 34 and the HVDC bus 32.

During the braking or deceleration phase, a regeneration of electrical energy is produced in the architecture.

The regenerated electrical energy is transmitted, depending on their state, to the electrical generator 26, or to the storage means 42, or to the motor 36, or to the braking resistor 46, according to the control-command law of voltage converters 30, 34, 44.

In particular, when the voltage of the HVDC bus 32 is between the voltage thresholds V1 and V2, the regenerated electrical energy is transmitted to the batteries.

When the voltage of the HVDC bus 32 is between the voltage thresholds V2 and V3, the regenerated electrical energy is transmitted to the electrical generator 26.

In the event that the voltage of the HVDC bus 32 is higher than the voltage threshold V3 and as long as the temperature of the motor 36 is lower than the predetermined temperature, the regenerated electrical energy is transmitted to the motor 36.

And when the temperature of the motor 36 is higher than the predetermined temperature, the regenerated electrical energy is transmitted to the brake resistor(s) 46.

Thus, the regenerated electrical energy is transmitted to the storage means 42 or to the electrical generator 26 by a reverse transmission of energy from the motor 36. In the event of a surplus of regenerated electrical energy, the latter is transmitted to the motor 36, then to the braking resistor(s) 46.

In particular, the inductor of the electric generator 26 is used as an inductor of the voltage converter 30 when the regenerated electric energy is transmitted to the electric generator 26.

In the acceleration phase, the electric generator 26 and the batteries supply electrical energy to the motor 36 when the voltage of the latter is greater than the voltage threshold V4.

Still in the acceleration phase, the electric generator 26 supplies electrical energy to the motor 36 and recharges the batteries when the voltage of the HVDC bus 32 is lower than the voltage threshold V4. The batteries are recharged up to the voltage threshold V5.

And finally, in the acceleration phase, the electrical generator 26 alone supplies electrical energy to the motor 36 when the voltage of the HVDC bus 32 is greater than the voltage threshold V5.

Claims (10)

Architecture (20) for transferring regenerated electrical energy in an aircraft, comprising:

• a reversible electric generator (26) driven by a mechanical shaft (24) and capable of delivering an alternating voltage,
• a first four-quadrant voltage converter (30) configured to convert an alternating voltage into direct voltage, and vice versa, the first voltage converter (30) being arranged at the output of the electric generator (26),
• a direct current and high voltage communication bus (32) powered by the first voltage converter (30),
• a reversible power electric motor (36), said motor (36) comprising a second voltage converter (34) able to operate on four quadrants and configured to convert a direct voltage into alternating voltage, and vice versa, the second voltage converter ( 34) being connected to said communication bus (32),
• electrical energy storage means (42) connected to said communication bus (32),
• a braking resistor (46), and
• a supervisor (48) configured to implement a control-command law for the first and second voltage converters (30, 34) to, depending on the state of components of the architecture, distribute the regenerated electrical energy to a or more of the members of the architecture, the members of the architecture being said storage means (42), the electric generator (26), said motor (36) and the braking resistor (46).

Architecture (20) according to the preceding claim, in which the control-command law is implemented in the supervisor (48) to distribute the regenerated electrical energy to:

• said storage means (42) when the voltage of said communication bus (32) is between a first and a second predetermined voltage (V1, V2), the second predetermined voltage (V2) being greater than the first predetermined voltage (V1) ,
• the electric generator (26) when the voltage of said communication bus (32) is between the second and a third predetermined voltage (V2, V3), the third predetermined voltage (V3) being higher than the second predetermined voltage (V2),
• said motor (36) when the voltage of said communication bus (32) is higher than the predetermined third voltage (V3) and when the temperature of said motor (36) is lower than a predetermined temperature,
• the braking resistor (46) when the temperature of said motor (36) is higher than the predetermined temperature.

Architecture (20) according to one of the preceding claims, also comprising a third bidirectional voltage converter (44) configured to convert a direct voltage into direct voltage, the third voltage converter (44) being arranged between the said storage means (42 ) and said communication bus (32), and in which the supervisor (48) is configured to implement a control-command law for the first, second and third voltage converters (30, 34, 44) for, depending on the state of the architectural organs, distribute the regenerated electrical energy to one or more of the architectural organs. Architecture (20) according to one of the preceding claims, in which the electrical generator (26) is a permanent magnet generator, or a synchronous generator with separate excitation, or a variable reluctance generator with separate excitation or self-excited. Architecture (20) according to one of the preceding claims, in which said storage means (42) comprise one or a plurality of batteries, for example of the Lithium-ion type, and/or one or a plurality of super-capacitors, and /or one or a plurality of ultra-capacitors. Architecture (20) according to one of the preceding claims, also comprising a high-bandwidth communication bus (50) connecting the supervisor (48) and the first and second voltage converters (30, 34), and in which the supervisor (48) is configured to control the voltage of this communication bus (50) by inverse voltage droop. Method for transferring regenerated electrical energy in an architecture (20) according to one of the preceding claims, in which in nominal operating mode, the electrical generator (26) is driven by the mechanical shaft (24) and supplies the power to said motor (36) via the first and second voltage converters (30, 34) and the communication bus (32) to direct current and high voltage, and characterized in that in the braking or deceleration phase, a regeneration of electrical energy is produced, and in that the regenerated electrical energy is transmitted, depending on the state of the components of the architecture, to a component of the architecture according to the control-command law of the first and second voltage converters (30, 34). Process according to the preceding claim, in which:

• when the voltage of said communication bus (32) is between the first and the second predetermined voltage (V1, V2), the regenerated electrical energy is transmitted to said storage means (42),
• when the voltage of said communication bus (32) is between the second and the third predetermined voltage (V2, V3), the regenerated electrical energy is transmitted to the electrical generator (26),
• when the voltage of said communication bus (32) is higher than the predetermined third voltage (V3) and when the temperature of said motor (36) is lower than the predetermined temperature, the regenerated electrical energy is transmitted to said motor (36), and
• when the temperature of said motor (36) is higher than the predetermined temperature, the regenerated electrical energy is transmitted to the braking resistor (46).

Method according to the preceding claim, comprising using the inductance of the electric generator (26) as the inductance of the first voltage converter (30) when the regenerated electric energy is transmitted to the electric generator (26). Method according to one of Claims 7 to 9, in which, in the acceleration phase:

• when the voltage of said communication bus (32) is greater than a fourth predetermined voltage (V4), the electrical generator (26) and said storage means (42) supply electrical energy to said motor (36),
• when the voltage of said communication bus (32) is lower than the fourth predetermined voltage (V4), the electric generator (26) supplies electric energy to said motor (36) and recharges said storage means (42) until a fifth predetermined voltage (V5), the fifth predetermined voltage (V5) being higher than the fourth predetermined voltage (V4), and
• when the voltage of said communication bus (32) is higher than the fifth predetermined voltage (V5), the electric generator (26) supplies electric energy to said motor (36).