System for transmitting a signal by power-line carriers through a rotating system in a turbine engine of an aircraft

Abstract

The invention relates to a system (10) for transmitting, by power-line carriers, a data signal to be transmitted (S1), in a turbine engine, which system comprises a power supply device (20, 120) comprising at least one unmovable part (22, 122) rigidly connected to the frame portion and configured to receive an input power signal (Pp1, E1); as well as a rotating part (24, 124) rigidly connected to the rotary drive element for rotation therewith and magnetically coupled to the unmovable part such that it is configured to output an output power signal (Pd1') for electrically powering the electrical equipment; a modulation unit (30) configured to apply at least one modulation to the data signal to be transmitted (S1) so as to output a modulated data signal to be transmitted (S1m) having a reduced energy level and a frequency that is higher than the frequency of the input power signal; and a coupling module (40) configured to superimpose the modulated data signal to be transmitted (S1m) onto the input power signal.

Description

Description Title of the invention: System for transmitting a signal by power line carrier currents through a rotating system in an aircraft turbomachine Technical Field The present invention relates to the field of systems for transmitting data signals, such as control or information signals, within aircraft. Aircraft traditionally include a turbomachine, which may be of the turboprop type, in which case it is equipped with a propeller external to the engine, or of the turbojet or turbofan type, in which case the propeller is called a fan and may be ducted or unducted. The propeller is integral with a rotating drive element, such as a shaft, which is configured to be driven in rotation by the turbomachine, relative to a portion of the aircraft frame. In other words, the rotating drive element and the propeller are driven in rotation relative to a fixed frame defined by the portion of the aircraft frame, and are arranged in a rotating frame.

[0002] Aircraft typically include one or more electrical components arranged in this rotating frame of reference, such as: a propeller blade de-icing system using heated mats that prevents ice from forming on the propeller blades; or a propeller blade pitch adjustment device comprising an electric motor rotationally linked to the rotating drive element.

[0003] Known solutions exist to provide, in the rotating frame of reference, the power necessary to supply electrical energy to these electrical equipment.

[0004] It is also necessary to ensure the transmission of data signals, and in particular control signals or information signals, from the fixed reference frame of the aircraft to these electrical equipment arranged in the rotating reference frame, in order to transmit to them information and / or instructions necessary for their control and operation. Previous technique

[0005] We know of power signal transmission systems, such as slip-ring devices, that allow power signals to be transmitted from the fixed reference frame of an aircraft to the rotating reference frame defined by the turbomachine propeller. Such a slip-ring is also called a "slip ring" in English. It ensures the continuous transmission of the power signal and its transfer from the fixed reference frame to the rotating reference frame via the contact of brushes on a slip ring. It is known to add dedicated tracks to these slip-ring devices for the passage of a serial communication link.

[0006] One drawback of this signal transfer solution is that the commutator brushes wear out quickly due to friction against the rotating commutator ring. These brushed commutators therefore require regular maintenance and have a particularly short lifespan. Furthermore, these brushed commutators are very heavy and bulky.

[0007] Optical data transmission systems are also known in aircraft. One drawback of these optical systems is that the optical sensors must be mounted directly on the propeller shaft. However, the available space on this shaft is particularly limited. These systems are therefore bulky, which is unsatisfactory given the limited space available inside aircraft. Furthermore, these optical sensors are sensitive to dust and dirt, making them unsuitable for the aircraft environment.

[0008] Magnetic transmission systems are also known, enabling the transmission of data signals from the fixed frame to the rotating frame. Such systems involve, for example, using an inductive device to transmit power to the rotating frame and a capacitive device to transmit data signals to the rotating frame. They therefore require a dedicated device for data signal transmission, making them particularly bulky. Furthermore, such a capacitive device for data signal transmission is not very robust and is particularly sensitive to any play that may exist between the various fixed and rotating parts within a turbomachine. Description of the invention

[0009] One aim of the present invention is to propose a system for transmitting a data signal by carrier currents in a turbomachine of an aircraft, remedying the aforementioned drawbacks.

[0010] To this end, the invention relates to a power line carrier transmission system for a data signal to be transmitted in a turbomachine of an aircraft, the turbomachine comprising a frame portion and a rotary drive element configured to be driven in rotation relative to said frame portion, the rotary drive element preferably comprising a shaft, the aircraft further comprising at least one electrical component fixed in rotation with said rotary drive element, the transmission system comprising: an electrical power supply device, for example a rotating transformer or an electric generator, comprising at least a fixed part attached to said portion of frame and configured to receive an input power signal; and a rotating part fixed in rotation with said rotating drive element and magnetically coupled with said fixed part so that it is configured to deliver an output power signal for supplying electrical power to said electrical equipment; a modulation unit configured to apply at least one modulation to the data signal to be transmitted so as to deliver a modulated data signal to be transmitted having a reduced energy level and a frequency higher than the frequency of said input power signal; and a coupling module configured to superimpose said modulated data signal to be transmitted onto said input power signal intended for the stationary part of the power supply device, the coupling module delivering to the stationary part of the power supply device said input power signal to which said modulated data signal to be transmitted has been superimposed. [OOllJThe frame portion of the aircraft turbomachine defines a fixed frame of reference. Preferably, the turbomachine includes a propeller integral with the rotating drive element. The rotating drive element and the propeller define a rotating frame of reference.]

[0012] Without limitation, the aircraft turbomachine advantageously comprises the system according to the invention. Without limitation, the turbomachine may be a turbofan or a turbojet, in which case the propeller is called a fan, or a turboprop. In other words, the term "propeller" covers both the propeller of a turboprop and the fan of a turbojet or turbofan.

[0013] The power supply device is a magnetic device. It is configured to deliver power taking into account the magnetic coupling between its rotating part and its fixed part, and taking into account the rotation of said rotating part.

[0014] Since the fixed part of the power supply device is fixed relative to the frame portion, it is located in the fixed frame. Since the rotating part of the power supply device is rotationally fixed to the rotating drive element, it is located in said rotating frame. This rotating part is advantageously supported by the rotating drive element.

[0015] Without limitation, the power supply device may include a rotating transformer, in which case the stationary part preferably comprises a primary circuit of the rotating transformer and the rotating part preferably comprises a secondary circuit of the rotating transformer. The input power signal is then a primary power signal that is transmitted between the primary and secondary circuits of the rotating transformer.

[0016] It is understood that when the power supply device includes a rotating transformer, its stationary part is configured to receive said input power signal and that the coupling module is configured to superimpose said modulated data signal to be transmitted onto this input power signal.

[0017] Alternatively, and without limitation, the power supply device may include an electric generator, in which case the stationary part preferably comprises an inductor of the electric generator and the rotating part preferably comprises a rotating armature of the electric generator. The input power signal is then an excitation signal intended for the inductor of the electric generator. This input power signal is used to adjust the amplitude of the output power signal delivered by the electric generator.

[0018] According to this variant, the amplitude of the output power signal is a function of the input power signal. The input power signal, which is an excitation signal in this case, has a current level on the order of 1 ampere.

[0019] It is understood that when the power supply device includes an electric generator, its stationary part is configured to receive said input power signal, which is an excitation signal, and that the coupling module is configured to superimpose said modulated data signal to be transmitted onto this input power signal.

[0020] The said electrical equipment is also located in the rotating frame. Without limitation, the electrical equipment may include, preferably consist of, a device for de-icing the blades of an aircraft propeller or a device for controlling the pitch of such a propeller blades. [002 l]The data signal to be transmitted is intended for said electrical equipment. The data signal to be transmitted can be generated and delivered by a control module located in the fixed reference frame. The data signal to be transmitted is advantageously delivered by the aircraft.

[0022] The data signal to be transmitted may consist of a control signal for the operation of said electrical equipment, for example, for controlling a de-icing device or a device for controlling the blade pitch of a propeller of the aircraft's turbomachine. The data signal to be transmitted may be an information signal intended for said electrical equipment. The data signal to be transmitted may, for example, include control parameters such as a period and / or a duty cycle of activation and deactivation phases of de-icing circuits of a de-icing device located in the rotating frame. Said data signal to be transmitted may be analog or digital. It advantageously has a low voltage level, preferably less than 10 volts. Without limitation, said data signal to be transmitted may consist of a word of several bits.

[0023] The modulation unit is advantageously fixed relative to the aircraft frame. It is advantageously positioned in the fixed reference frame.

[0024] Without limitation, the modulation unit can be configured to apply frequency modulation, amplitude modulation, or orthogonal frequency division multiplexing to the data signal to be transmitted. Without limitation, the modulation unit can be configured to apply single-carrier or multi-carrier modulation to the data signal to be transmitted.

[0025] Preferably, the modulation unit is configured to apply narrowband frequency modulation to the data signal to be transmitted. One advantage is that it enables robust and deterministic transmission of the data signal, particularly in noisy environments, while remaining compatible with the bandwidth of the materials commonly used in the manufacture of the power supply device.

[0026] Without limitation, said modulation unit can also be configured to apply coding to said data signal to be transmitted.

[0027] Preferably, the modulated data signal to be transmitted has a high frequency, advantageously between 35 kHz and 472 kHz. This frequency range notably includes the CENELEC A frequency band and the FCC frequency band commonly used for power line carrier transmission systems.

[0028] By "reduced energy" we mean that the modulated data signal to be transmitted preferably has a lower energy level, preferably much lower, than the energy level of the input power signal. The modulated data signal to be transmitted is also said to be low-energy.

[0029] Preferably, the AC power supply device is configured to receive an input power signal, of the primary power type, and is configured to transmit this input power signal from its stationary part to its rotating part. The output power signal then corresponds substantially to the transmitted input power signal.

[0030] Preferably, the input power signal is an alternating signal. This is particularly the case when the power supply device includes a rotating transformer whose primary circuit is configured to receive such an alternating signal. Alternatively, and without departing from the scope of the invention, said input power signal may be a direct current signal.

[0031] According to another advantageous embodiment, the AC power supply device is configured to deliver an output power signal from an excitation signal as the input power signal. This is particularly the case when the power supply device includes an electric generator. Preferably, the input power signal is then a direct current signal. Alternatively, and without departing from the scope of the invention, said input power signal may be an alternating current signal.

[0032] Preferably, the input power signal has a current level greater than or equal to 0.5 Amperes.

[0033] Without limitation, the input power signal may be a primary power signal intended to be transmitted by a rotating transformer, or an excitation signal intended for the inductor of an electric generator.

[0034] In the case where the input power signal is an alternating signal, the latter advantageously has a frequency between 50 Hz and 5 kHz.

[0035] The input power signal advantageously has a voltage level of approximately 100 volts RMS, for example, 115 volts RMS. Alternatively, and without limitation, the input power signal may have a higher voltage level, preferably around 540 volts RMS or even more preferably around 800 volts RMS. One benefit is improved energy efficiency and a reduction in harness weight.

[0036] The coupling module is advantageously fixed relative to the frame portion. It is advantageously positioned in the fixed frame.

[0037] The coupling module is configured to perform the superposition, or coupling, of the modulated data signal to be transmitted with the input power signal. In other words, the coupling module of the transmission system according to the invention provides for superimposing a modulated data signal to be transmitted onto the input power signal. This data signal is of low energy but higher frequency than the input power signal. This superposition consists of adding the input power signal and the modulated data signal to be transmitted. The superposition of two signals is defined as the sum of their amplitudes at each instant. This coupling module enables the implementation of power line communication (PLC) transmission, which involves superimposing a low-energy, high-frequency signal onto a higher-energy power signal.

[0038] It is understood that the fixed part of the power supply device receives said input power signal, for example the primary power signal or the excitation signal, to which said modulated data signal to be transmitted has been superimposed.

[0039] Preferably, the coupling module is configured to inject said input power signal, to which the modulated data signal to be transmitted has been superimposed, at the level of the fixed part of the power supply device, for example at the level of the primary circuit of a rotating transformer.

[0040] The coupling module advantageously includes an injection element, for example an injection capacity.

[0041] The power supply unit receives at its stationary input the input power signal, to which the modulated data signal to be transmitted has been superimposed. The modulated data signal is then transmitted from the stationary unit to the rotating unit of the power supply unit, taking into account their magnetic coupling. Advantageously, the modulated data signal is transmitted either simultaneously with the transmission of the input power signal, for example via a rotating transformer, or simultaneously with the generation of the output power signal, for example generated by an electric generator. Without limitation, the modulated data signal can be physically transmitted by magnetic coupling and / or via a wired connection between the stationary unit and the rotating unit.

[0042] It is understood that the output power signal delivered by the rotating part of the power supply device includes the modulated transmitted data signal as well as the power signal for supplying electrical energy to the electrical equipment. This output power signal must then be processed, in particular to separate the modulated transmitted data signal from the power signal.

[0043] By superimposing the modulated data signal to be transmitted, which has a high frequency and low energy, onto the input signal supplied to the power supply device, the transmission system according to the invention enables the transmission of the data signal using a power line carrier (PLC) technique. The invention proposes applying this PLC transmission technique using a magnetic power supply device, traditionally used to transmit power from a fixed reference frame to a rotating reference frame within an aircraft. In other words, according to the invention, the power supply device behaves as a PLC transmission device.The fixed part of the power supply device forms a transmitter of line-carrying currents, while the rotating part of the power supply device forms a receiver of line-carrying currents.

[0044] Such transmission of the data signal by power line carrier is particularly reliable, robust and allows the transmission of a large volume of data.

[0045] Furthermore, the transmission system according to the invention allows the use of a single magnetic power supply device, such as a rotating transformer or an electric generator, to deliver power to the electrical equipment located in the rotating beacon and to transmit the data signal to said electrical equipment. The transmission system combines the power supply device to distribute the electrical power and transmit the data signal to the rotating beacon. The invention eliminates the need to use two separate devices to perform these two functions, and in particular, the need to integrate an independent data signal transfer system. This frees up significant space within the aircraft.

[0046] The use of such a power supply device, configured and particularly adapted to deliver power and at first glance not optimized for the transfer of high-frequency signals, to transmit a data signal via a power line carrier technique, generally used in home networks or smart networks, does not appear immediately.

[0047] The invention also makes it possible to do without the use of a brush collector, reducing wear and maintenance needs of the transmission system.

[0048] Preferably, the transmission system is reversible, so that it also allows a data signal to be transmitted from the rotating frame to the fixed frame.

[0049] Advantageously, the modulation unit is configured so that the modulated data signal it delivers has a frequency at least one decade higher than the frequency of the input power signal. This facilitates the subsequent separation of the transmitted data signal from the output power signal by the AC power supply, using signals with correspondingly different frequency ranges.

[0050] Preferably, the modulation unit is configured to apply frequency modulation and / or amplitude modulation to the data signal to be transmitted. The choice of modulation type depends in particular on the nature of the power supply device and its intrinsic characteristics.

[0051] Advantageously, the modulation unit is configured to apply multi-carrier modulation to the data signal to be transmitted, for example, orthogonal frequency division multiplexing (OFDM) or coded OFDM. Several carrier signals with different frequencies are then used to perform the signal modulation. It is understood that the same data signal to be transmitted is preferably modulated multiple times, using several distinct carriers, resulting in a plurality of modulated signal components. All these modulated signal components are advantageously transmitted simultaneously. This redundancy improves the reliability of the signal transmission.

[0052] It is also known that the power signals used to supply electrical equipment in the rotating parts of aircraft generally have a frequency spectrum that includes unwanted harmonics. In particular, when the power supply system includes a rotating transformer, it must be supplied with an alternating power signal. However, harmonics are generated by the rapid voltage switching resulting from the conversion of direct current to alternating current. Multicarrier modulation makes it possible to suppress these harmonics by selecting carriers outside of these harmonics.

[0053] The choice of different carriers is advantageously made during the design phase or adaptively depending on the disturbances encountered during the operation of the transmission system.

[0054] Orthogonal frequency-division multiplexing (OFDM) modulation uses a plurality of distinct, orthogonal carriers to modulate the signal.

[0055] Coded orthogonal frequency-division multiplexing is also called COFDM modulation for "coded orthogonal frequency-division multiplexing" in English.

[0056] Advantageously, said coupling module is configured to achieve inductive or capacitive coupling between the modulated data signal to be transmitted and said input power signal.

[0057] Preferably, the output power signal includes a modulated transmitted data signal, and the transmission system further includes a decoupling module configured to separate the modulated transmitted data signal from the output power signal. The decoupling module provides, on the one hand, the modulated transmitted data signal and, on the other hand, the output power signal, preferably a filtered output power signal from which the modulated transmitted data signal has been removed.

[0058] The output power signal supplied to said decoupling module is advantageously, but not necessarily, an analog signal.

[0059] The modulated transmitted data signal advantageously corresponds to the modulated data signal to be transmitted, such that these signals exhibit substantially the same characteristics. The modulated transmitted data signal and the modulated data signal to be transmitted are not necessarily strictly identical, particularly given inaccuracies, errors, and / or disturbances that can generate a difference between these two signals during signal transmission.

[0060] The decoupling module is advantageously rotationally fixed to the rotating drive element. It is advantageously arranged in the rotating frame of reference.

[0061] The said decoupling module is advantageously connected, preferably directly, to the said rotating part of the power supply device.

[0062] Preferably, the decoupling module is configured to filter the output power signal to separate the modulated transmitted data signal from the output power signal. Preferably, said decoupling module is configured to apply a high-pass filter to said output power signal.

[0063] Preferably, the transmission system further includes a demodulation unit configured to apply demodulation to said modulated transmitted data signal and to deliver a demodulated transmitted data signal.

[0064] The demodulated transmitted data signal is advantageously supplied to the electrical equipment. It includes information and / or instructions intended for that electrical equipment. The demodulated transmitted data signal may be digital or analog.

[0065] The demodulated transmitted data signal advantageously corresponds to the data signal to be transmitted, such that these signals have substantially the same characteristics. The demodulated transmitted data signal advantageously comprises the same data as the data signal to be transmitted. The demodulated transmitted data signal and the data signal to be transmitted are not necessarily strictly identical, particularly given the inaccuracies, errors, and / or disturbances that may generate a difference between these two signals during transmission.

[0066] The said demodulation unit is advantageously rotationally fixed to the said rotary drive element. It is advantageously arranged in the rotating frame of reference.

[0067] Preferably, said demodulation unit is also configured to apply decoding to said modulated transmitted data signal.

[0068] Preferably, the demodulation unit is configured to detect errors in the demodulated transmitted data signal. It is further advantageously configured to correct any errors detected. One benefit is to further improve the reliability of the data transmission.

[0069] According to an advantageous embodiment, the aircraft comprises an electrical power source fixed to the aircraft frame and configured to provide the input power signal, and the power supply device comprises a rotating transformer having a primary circuit fixed to the aircraft frame and configured to receive the input power signal, to which the modulated data signal to be transmitted has been superimposed, and a secondary circuit fixed and rotating with the rotating drive element and magnetically coupled to the primary circuit so as to deliver the output power signal. Such a power transformer is particularly well-suited for power transmission, so its use for transmitting data signals by a power line carrier method is not immediately apparent.

[0070] In this variant, the coupling module is configured to superimpose the modulated data signal to be transmitted onto the input power signal. The input power signal is alternating current (AC). The coupling module is advantageously configured to inject the input power signal, with the modulated data signal superimposed, into the primary circuit of the rotating transformer.

[0071] The stationary part of the power supply system preferably comprises the primary circuit of the rotating transformer. The primary circuit of the rotating transformer advantageously comprises at least one winding. The rotating part of the power supply system preferably comprises the secondary circuit of the rotating transformer. The primary circuit is located in the stationary frame, while the secondary circuit is located in the rotating frame. The secondary circuit of the rotating transformer advantageously comprises at least one winding.

[0072] In this embodiment, the input power signal, to which the modulated data signal to be transmitted has been superimposed, is transmitted from the fixed reference frame to the rotating reference frame through the rotating transformer. The transmission system then allows the data signal to be transmitted simultaneously with the power signal.

[0073] Preferably, but not exclusively, said power supply device consists of said rotating transformer.

[0074] According to another advantageous variant, the transmission system includes an excitation device configured to provide said input power signal and an electric generator comprising an inductor fixed relative to the portion of the aircraft frame and configured to receive said input power signal to which has been superimposed said modulated data signal to be transmitted, and an armature fixed in rotation with the rotating drive element and magnetically coupled to said inductor so that it delivers said output power signal.

[0075] According to this variant, the input power signal is an excitation signal intended for the inductor of the electric generator.

[0076] In this variant, the coupling module is configured to superimpose the modulated data signal to be transmitted onto the input power signal supplied by the excitation device. The coupling module is advantageously configured to inject the resulting superimposed signal into the inductor of the electric generator.

[0077] According to this variant, the stationary part of the power supply device comprises, preferably, the inductor of the electric generator. The rotating part of the power supply device comprises, preferably, the armature of the electric generator. The inductor is located in the stationary frame of reference, while the armature is located in the rotating frame of reference.

[0078] According to this variant, the modulated data signal to be transmitted is at least partially transmitted physically via the magnetic coupling between the inductor and armature of the generator. Without limitation, the modulated data signal to be transmitted may also be transmitted at least partially via a wired connection.

[0079] Advantageously, at the frequency of the carrier signal, the electric generator behaves from a magnetic point of view like a transformer.

[0080] Preferably, but not exclusively, said power supply device consists of said electric generator.

[0081] Advantageously, the transmission system is reversible, so that it allows data signals to be transmitted from the electrical equipment located in the rotating frame to the fixed frame.

[0082] Preferably, the transmission system further includes a secondary transmission device for transmitting into the aircraft a secondary data signal supplied by said electrical equipment, said power supply device being configured to transmit said secondary data signal from its rotating part to its fixed part.

[0083] This secondary transmission device allows a secondary data signal to be transmitted from the rotating frame to the fixed frame. One advantage is that it makes the transmission system reversible, thus enabling the collection of various data related to the electrical equipment in the fixed frame, such as monitoring information, temperature measurements, or blade position readings.

[0084] Preferably, said secondary transmission device includes a secondary modulation unit configured to apply modulation to said secondary data signal.

[0085] Preferably, the secondary modulation unit is rotationally linked to the rotating drive element, so that it is positioned in the rotating frame of reference. Preferably, the secondary modulation unit and the demodulation unit form a single unit.

[0086] The invention also relates to a method for transmitting a data signal by power line carrier currents in an aircraft turbomachine, the turbomachine comprising a frame portion and a rotary drive element configured to be driven in rotation relative to said frame portion, the rotary drive element preferably comprising a shaft, the aircraft further comprising at least one electrical component fixed in rotation with said rotary drive element, the transmission method comprising the steps according to which: an electrical power supply device is provided, for example a rotating transformer or an electric generator, comprising at least a fixed part attached to said portion of frame and configured to receive an input power signal; and a rotating part fixed in rotation with said rotating drive element and magnetically coupled with said fixed part so that it is configured to deliver an output power signal for supplying electrical power to said electrical equipment; an input power signal is supplied to the fixed part of the power supply device; said data signal to be transmitted is supplied; a modulation is applied to the said data signal to be transmitted so as to provide a modulated data signal to be transmitted having a reduced energy level and a frequency higher than the frequency of said input power signal; the modulated data signal to be transmitted is superimposed on the input power signal intended for the fixed part of the power supply device; and the input power signal, to which the modulated data signal to be transmitted has been superimposed, is delivered to the fixed part of the power supply device. Brief description of the drawings

[0087] The attached drawings are schematic and are primarily intended to illustrate the principles of the presentation.

[0088] The invention will be better understood upon reading the following description of embodiments of the invention given by way of non-limiting examples, with reference to the accompanying drawings, in which:

[0089] [Fig. 1] Figure 1 illustrates a first embodiment of a transmission system according to the invention, in which the power supply device includes a rotating transformer;

[0090] [Fig. 2] Figure 2 shows an example of a data signal to be transmitted by the transmission system;

[0091] [Fig. 3] Figure 3 shows a frequency representation of a data signal to be transmitted modulated by means of the modulation unit;

[0092] [Fig. 4] Figure 4 shows the voltage and current components of an input power signal intended for the primary circuit of the rotating transformer;

[0093] [Fig. 5] Figure 5 illustrates a superposition of a modulated data signal to be transmitted with an input power signal, such as that implemented by the coupling module of the transmission system; and

[0094] [Fig. 6] Figure 6 illustrates a second embodiment of a transmission system according to the invention, in which the power supply device includes an electric generator. Description of the implementation methods

[0095] The invention relates to a system for transmitting a data signal by line carrier currents in an aircraft, allowing such a data signal to be transmitted from a fixed reference frame to electrical equipment arranged in a rotating reference frame linked to a rotating drive element and a propeller of the aircraft.

[0096] To make the explanation more concrete, several embodiments of a transmission system 10 according to the invention are described in detail below, with reference to the accompanying drawings. It should be noted that the invention is not limited to these examples.

[0097] Figure 1 is a functional diagram representing a first embodiment of a transmission system 10, according to the invention, given by way of non-limiting example. In this Figure 1, it can be seen that the aircraft comprises a turbomachine including a frame portion 12 defining a fixed reference frame. The turbomachine also includes a rotary drive element 14, for example a rotating support, configured to be driven in rotation about an axis of rotation X relative to said frame portion 12. The rotary drive element 14 includes a shaft, such as a low-pressure turbomachine shaft, and is driven in rotation by a turbomachine of the aircraft. In this non-limiting example, the turbomachine further includes a propeller 16, which is shown here as an unfaired propeller. For clarity, only one blade 17 of the propeller 16 is shown here.The propeller 16 is carried by the rotating drive element 14 so that it is configured to be driven in rotation about said axis of rotation X, relative to the portion of the frame 12. The propeller 16 and the rotating drive element 14 define a rotating frame.

[0098] The aircraft further includes a fixed power supply 18 relative to the frame portion 12. The power supply 18 comprises a DC bus, consisting of a continuous power supply network for the aircraft, and an inverter. This power supply 18 is configured to deliver an alternating current input power signal.

[0099] The aircraft also includes electrical equipment 70 consisting in this non-limiting example of a device for de-icing the blades 17 of the propeller 16. This de-icing device includes a plurality of controllable heating mats to prevent ice formation on the propeller blades. The electrical equipment 70 is rotationally fixed to the rotating drive element 14 and is located in the rotating frame. The electrical equipment must be supplied with electrical power.

[0100] In this non-limiting example, the aircraft also includes a control module 19 configured to generate and provide a data signal to be transmitted to said electrical equipment 70.

[0101] The transmission system 10 allows such a data signal to be transmitted from the fixed reference frame to the electrical equipment 70 located in the rotating reference frame.

[0102] As shown in Figure 1, the transmission system 10 includes a rotating transformer 20, forming a power supply device. This rotating transformer 20 comprises a primary circuit 22 fixed relative to the frame portion 12 and positioned in the fixed frame. The primary circuit 22 comprises a plurality of primary windings. The rotating transformer 20 further comprises a secondary circuit 24 fixed in rotation with the rotating drive element 14 and positioned in the rotating frame. The secondary circuit 24 is therefore free to rotate relative to the primary circuit 22. The secondary circuit is rotationally linked to the propeller 16. The secondary circuit 24 comprises a plurality of secondary windings.

[0103] The secondary circuit 24 is magnetically coupled to the primary circuit 22, thereby configuring the rotating transformer 20 to transmit power from the fixed frame to the rotating frame. More precisely, the primary circuit 22 is configured to receive an alternating current input power signal, leading to the delivery, by the secondary circuit 24, of an output power signal Pdi', or alternatively, a secondary power signal, also alternating current, given the magnetic coupling and the rotation of the secondary circuit.

[0104] As illustrated in Figure 1, the transmission system 10 also includes a modulation unit 30 configured to apply modulation to the data signal to be transmitted. The modulation unit 30 is fixed relative to the frame portion 12 and is positioned in the fixed coordinate system.

[0105] The modulation unit 30 is configured to receive the data signal to be transmitted. An example of such a data signal to be transmitted, Si, is shown in Figure 2. This signal, Si, is an eight-bit digital signal, encoded in 0-volt and 5-volt values. This data signal to be transmitted, Si, is a control signal for the electrical equipment 70, comprising instructions for the selective activation of defrosting circuits in said electrical equipment 70.

[0106] The modulation unit 30 is configured to apply multiple-carrier modulation, of the orthogonal frequency division multiplexing (OFDM) type, to the data signal to be transmitted, Si. The data signal to be transmitted, Si, is modulated from several mutually orthogonal carrier signals to provide redundancy, thus improving the robustness of the signal transmission. This modulation unit can also be configured to apply amplitude modulation or frequency modulation. The modulation unit 30 delivers a modulated data signal to be transmitted, Sim. This signal, Sim, comprises several signal components, each corresponding to a modulation of the data signal to be transmitted using one of the different carriers. These signal components are transmitted simultaneously to ensure redundant transmission of the data signal.

[0107] A frequency representation of this Sim modulated data signal to be transmitted is given in Figure 3. This figure shows the amplitude A of the frequency components of the Sim modulated data signal to be transmitted for the different frequencies f.

[0108] As illustrated in Figure 1, the transmission system also includes a coupling module 40 connected between the modulation unit 30 and the primary circuit 22 of the rotating transformer 20, as well as between the power supply 18 and the rotating transformer. The coupling module 40 is fixed relative to the frame portion and is positioned in the fixed coordinate system. The coupling module 40 receives the modulated data signal Sim to be transmitted, delivered by the modulation unit 30. The coupling module also receives an input power signal P pi supplied by said power source 18 and intended to supply electrical power to electrical equipment 70.

[0109] The input power signal P pi is illustrated in Figure 4. This input power signal P pi This is a primary power signal intended for the primary circuit 22 of the rotating transformer 20. It is an alternating signal. More precisely, Figure 4 illustrates the evolution of an input voltage V pi supplied by a full-wave controlled inverter and the evolution of an input electric current I p i, associated with this input power signal P p i. The input power signal has a voltage level of approximately 115 Volts RMS. The modulated data signal to be transmitted, Sim, has a reduced energy level, advantageously much lower, compared to the energy level of the input power signal P. pi. The modulated data signal to be transmitted Sim also has a higher frequency, here slightly more than a decade higher, than the frequency of said input power signal P p i. [OlllJThe coupling module 40 is configured to superimpose said modulated data signal to be transmitted Sim onto said input power signal P p i. The invention therefore provides for superimposing a low-energy, high-frequency modulated Sim data signal to be transmitted onto an input power signal P p i. Such a superposition enables transmission via power line carriers (PLC). For readability, the signal resulting from the superposition of the modulated data signal to be transmitted, Sim, onto the input power signal, P piis not illustrated, insofar as this resulting signal is not easily interpretable and insofar as it is not possible to distinguish the signals which compose it in its temporal representation.

[0112] Therefore, the superposition technique is illustrated schematically in Figure 5, using a general case for arbitrarily chosen signals. This figure shows that a data signal S, having a low energy level and a high frequency, is superimposed on a power signal P of high energy and reduced frequency, according to a method commonly used for line-to-line power line communication. The result is a signal comprising the superimposed data and power signals.

[0113] According to the above, the coupling module 40 delivers a signal P pi' resulting from the superposition of said modulated data signal to be transmitted Sim with said input power signal P p i. The coupling module provides this resulting signal P p i' to the primary circuit 22 of the rotating transformer 20, which constitutes the stationary part thereof. Preferably, the coupling module is configured to inject this resulting signal P p i' at the level of the primary winding 22 by means of an injection component, for example an injection capacitor.

[0114] Given the magnetic coupling between the primary circuit 22 and the secondary circuit 24 of the rotating transformer 20, said secondary circuit 24 then delivers an output power signal Pdi'. This output power signal has the same frequency components as the signal P p i' resulting from the superposition of said modulated data signal to be transmitted Sim with said input power signal P pi. This output power signal Pdi' comprises a modulated transmitted data signal component and a power signal component for supplying electrical power to electrical equipment 70.

[0115] The transmission system 10 further includes a decoupling module 50 connected to the secondary circuit 24 of the rotating transformer 20. This decoupling module 50 is configured to filter the output power signal Pdi' so as to separate a transmitted modulated Simt data signal from this output power signal Pdi'. The decoupling module applies a high-pass filter. The decoupling module 50 delivers, on the one hand, a filtered output power signal Pdi, devoid of the data signal, and on the other hand, the transmitted modulated Simt data signal, corresponding to the Sim modulated data signal to be transmitted. The filtered output power signal Pdi is supplied to the electrical equipment 70 to provide it with electrical energy.

[0116] The transmission system further includes a demodulation unit 60 configured to demodulate the transmitted modulated Simt data signal in order to deliver a transmitted data signal Su corresponding to the transmitted data signal Si. The transmitted data signal Su is a digital signal and contains the same information as the transmitted data signal Si. It is advantageously substantially identical to the transmitted data signal. The demodulation unit 60 can also perform decoding of the transmitted modulated Simt data. This transmitted data signal Su is supplied to the electrical equipment 70 to control the activation of the defrosting circuits of said electrical equipment 70.

[0117] The transmission system 10 transmits the data signal through the rotating transformer 20 using a power line carrier technique. A single rotating transformer 20 simultaneously transmits, from the fixed reference frame to the rotating reference frame, both the power signal for supplying electrical energy to the electrical equipment and the data signal destined for that equipment.

[0118] In this non-limiting example, the transmission system 10 is reversible and includes a secondary transmission device formed by the demodulation unit 60, which forms a secondary modulation unit, by the rotating transformer 20 and by the modulation unit 30, which forms a secondary demodulation unit.

[0119] The electrical equipment 70 provides at least one secondary data signal to the secondary modulation unit, which applies modulation to this secondary data signal. The modulated secondary data signal is supplied to the secondary circuit 24 of the transformer 24 and is transmitted to the primary circuit 22. The secondary demodulation unit demodulates the modulated secondary data signal and delivers a transmitted secondary data signal.

[0120] Figure 6 illustrates a second embodiment of a transmission system 10, in which the rotating transformer 20 is replaced by an electric generator 120. The electric generator 120 constitutes a power supply device. This electric generator comprises an inductor 122, configured to receive an excitation signal constituting said input power signal, and an armature 124 magnetically coupled to the inductor so that it delivers an output power signal Pdi'.

[0121] The inductor 122 is fixed relative to the aircraft frame portion 12 and is located in the fixed frame. The armature 124 is fixed to the rotating drive element 14 and is located in the rotating frame.

[0122] In this second embodiment, the transmission system includes an excitation device 110 configured to deliver said excitation signal Ei, forming an input power signal, to the inductor 122 of the electric generator 120.

[0123] In this variant, the coupling module 40 is configured to superimpose the modulated data signal Sim to be transmitted onto the excitation signal Ei. The coupling module 40 delivers a signal Ei' resulting from the superposition of the modulated data signal Sim to be transmitted with the excitation signal Ei. The coupling module 40 supplies this resulting signal Ef to the inductor 122 of the electric generator 120, which constitutes the stationary part of the latter.

[0124] Given the magnetic coupling between the armature and the inductor of the electric generator 120, said armature delivers a power signal Pdi' which includes the modulated data signal transmitted Simt.

Claims

Tl Demands

1. A transmission system (10) by line-carrying currents for a data signal (Si) to be transmitted in a turbomachine of an aircraft, the turbomachine comprising a frame portion (12) and a rotary drive element (14) configured to be driven in rotation relative to said frame portion, the rotary drive element preferably comprising a shaft, the aircraft further comprising at least one electrical equipment (70) fixedly and rotationally connected with said rotary drive element, the transmission system comprising: an electrical power supply device (20,120), for example a rotating transformer or an electrical generator, comprising at least a fixed part (22,122) integral with said portion of frame and configured to receive an input power signal (Ppi,Ei); and a rotating part (24,124) integral in rotation with said rotating drive element and magnetically coupled with said fixed part so that it is configured to deliver an output power signal (Pdi') for supplying electrical power to said electrical equipment; a modulation unit (30) configured to apply at least one modulation to the data signal to be transmitted (Si) so as to deliver a modulated data signal to be transmitted (Sim) having a reduced energy level and a frequency higher than the frequency of said input power signal; and a coupling module (40) configured to superimpose said modulated data signal to be transmitted (Sim) on said input power signal (Ppi,Ei) intended for the fixed part of the power supply device, the coupling module delivering to the fixed part of the power supply device said input power signal to which said modulated data signal to be transmitted has been superimposed.

2. Transmission system according to claim 1, wherein the modulation unit (30) is configured such that the modulated data signal to be transmitted (Sim) which it delivers has a frequency at least one decade higher than a frequency of said input power signal (Ppi,Ei).

3. Transmission system according to claim 1 or 2, wherein the modulation unit (30) is configured to apply to the data signal to be transmitted (Si) frequency modulation and / or amplitude modulation.

4. A transmission system according to any one of claims 1 to 3, wherein the modulation unit (30) is configured to apply to the data signal to be transmitted (Si) a multi-carrier modulation, for example an orthogonal frequency division multiplexing type modulation or a coded orthogonal frequency division multiplexing type modulation.

5. Transmission system according to any one of claims 1 to 4, wherein said coupling module (40) is configured to achieve inductive or capacitive coupling between the modulated data signal to be transmitted (Sim) and said input power signal (Ppi,Ei).

6. A transmission system according to any one of claims 1 to 5, wherein said output power signal (Pdi') includes a modulated transmitted data signal (Simt), and wherein the transmission system (10) further comprises a decoupling module (50) configured to separate said modulated transmitted data signal (Simt) from said output power signal (Pdi').

7. A transmission system according to claim 6, further comprising a demodulation unit (60) configured to apply demodulation to said modulated transmitted data signal (Simt) and to deliver a demodulated transmitted data signal (Su).

8. A transmission system according to any one of claims 1 to 7, wherein said aircraft comprises an electrical power source (18) fixed relative to the frame portion (12) of the aircraft and configured to provide said input power signal (P p(i), and wherein said power supply device comprises a rotating transformer (20) having a primary circuit (22) fixed to the portion of the aircraft frame and configured to receive said input power signal to which said modulated data signal to be transmitted (Sim) has been superimposed, and a secondary circuit (24) fixed in rotation with said rotating drive element (14) and magnetically coupled to the primary circuit so that it delivers said output power signal (Pdi').

9. A transmission system according to any one of claims 1 to 7, comprising an excitation device (110) configured to provide said input power signal (Ei) and an electric generator comprising an inductor fixed relative to the portion of the aircraft frame and configured to receive said input power signal to which said modulated data signal to be transmitted has been superimposed, and an armature fixed in rotation with the rotating drive element and magnetically coupled to said inductor so that it delivers said output power signal.

10. A method for transmitting a data signal (Si) by means of power line carriers to be transmitted in a turbomachine of an aircraft, the turbomachine comprising a frame portion (12) and a rotary drive element (14) configured to be driven in rotation relative to said frame portion, the rotary drive element preferably comprising a shaft, the aircraft further comprising at least one electrical component (70) fixedly and rotationally connected with said rotary drive element, the transmission method comprising the steps in which: an electrical power supply device (20,120), for example a rotating transformer or an electrical generator, is provided, comprising at least a fixed part (22,122) attached to said portion of frame and configured to receive an input power signal; and a rotating part (24,124) fixed in rotation with said rotating drive element and magnetically coupled with said fixed part so that it is configured to deliver an output power signal (Pdi') for supplying electrical power to said electrical equipment; an input power signal (Ppi,Ei) is supplied to the fixed part of the power supply device; said data signal to be transmitted is provided (Si); a modulation is applied to the said data signal to be transmitted so as to provide a modulated data signal to be transmitted (Sim) having a reduced energy level and a frequency higher than the frequency of said input power signal; the modulated data signal to be transmitted is superimposed on the input power signal intended for the fixed part of the power supply device; and the input power signal, to which the modulated data signal to be transmitted has been superimposed, is delivered to the fixed part of the power supply device.

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