De-icing process for a turboprop engine

Abstract

De-icing method in a de-icing system (1) of a turboprop (100) comprising a fixed part (2) including an inverter (4) and an anti-icing control unit (7), a rotating part (3) including a rotary control unit (5) and a heating mat (9), and a rotary transformer (8) between the fixed and rotating parts, the method comprising upstream data transfers from the rotary control unit to the anti-icing control unit and downstream data transfers from the anti-icing control unit to the rotary control unit, wherein the method includes encoding steps: downstream data into frequency modulations of a supply voltage provided by the inverter around a predetermined nominal frequency; and upstream data into predetermined series of changes in an electrical power consumed by the rotary control unit.Figure for the abbreviation: [Fig.1].

Description

Title of the invention: De-icing method for a turboprop Technical field of the invention

[0001] The invention relates to the field of de-icing in an aircraft turboprop engine. In particular, the invention relates to bidirectional data transfer, especially for a turboprop de-icing system. prior art

[0002] A turboprop 100 (with reference to [Fig. 1]) comprises, in a simplified and known manner, a de-icing system 1, a fixed part 2, and a rotating part 3. The fixed part 2 is attached to a motor vehicle or aircraft. The de-icing system 1 is distributed between the fixed part 2 and the rotating part 3. The fixed part 2 comprises an engine or turbomachine, a control unit for the latter, an anti-icing control unit 7, a high-voltage DC power supply 6, and an inverter 4. The engine drives the rotating part 3. The rotating part 3 comprises propellers connected to a rotating shaft, one free end of which has a spinner, and a rotary control unit 5 for managing heating mats 9 positioned on the propeller blades and on the spinner.

[0003] The frost protection of the rotating part 3 is activated only in icing conditions and is carried out according to a principle known per se as follows: on the one hand, de-icing protection which concerns the leading edges of the propeller blades and sectors of the front cone, and on the other hand, anti-icing protection which concerns the tip of the cone.

[0004] The principle of defrosting protection consists of intermittently supplying the heating mats 9 after allowing frost to form on the surfaces concerned. This principle makes it possible to detach the layer of ice and, by rotation (centrifugation), to eject the blocks of ice thus formed.

[0005] The principle of anti-icing protection, on the other hand, is often used for fixed surfaces or surfaces subjected to low centrifugal forces or requiring a moderate level of power (a few kW in total). For these surfaces, the heating mats 9 must be continuously supplied with power in icing conditions to prevent frost formation.

[0006] The two aforementioned protection principles are implemented by the turboprop de-icing system 1, which includes an electric de-icing system for the propellers and the nose cone. It comprises several cascaded components as follows. First, it includes a DC / AC converter 40 whose main function is to converting direct current into alternating current to power a primary of a rotary transformer 8. The DC / AC converter 40 and the primary of the rotary transformer are mounted on the fixed part 2 of the turboprop 1.

[0007] The de-icing system 1 then comprises the rotary transformer 8 (RTU: Rotating Transformer Unit). It is known in itself, is non-contact, and its main function is to transfer power by electromagnetic induction between the fixed primary and a rotating secondary. An air gap between the fixed primary and the rotating secondary can be several millimeters (between 2 and 4 mm) and is subject to variations due to the operating modes of the turboprop engine, thermal expansion, and vibrations.

[0008] The de-icing system 1 then includes a rotating control unit 5 (RCU) whose main function is to sequentially distribute the power received from the secondary winding of the rotary transformer 8 to the heating mats 9 of the various propeller blade pairs and the nose cone. The sequential power supply to the blade pairs aims to limit the instantaneous power drawn from the main generators and also to avoid oversizing the entire electrical de-icing system. This principle of sequential operation is known per se.

[0009] Finally, the de-icing system 1 supplies power to the propeller blades and the front cone equipped with heating mats 9 operating by electrothermal effect based on a network of resistances integrated into the blades and the front cone at the level of the areas exposed to frost.

[0010] To ensure efficient de-icing of the blades and the front cone, the de-icing system 1 operates with three quantities: the de-icing power level, the de-icing activation time, and the de-icing cycle time.

[0011] These three quantities are generated by the Icing Protection Control Unit (IPCU) 7 of the defrosting system 1 based on the icing conditions provided by the turbomachine control unit. The Icing Protection Control Unit 7 communicates these three quantities to the DC / AC converter 40 and the rotating control unit 5. Specifically, the control of the "power level" transferred from the stationary part 2 to the rotating part via the rotary transformer 8 is ensured by the DC / AC converter 40 according to instructions from the Icing Protection Control Unit 7. Conversely, the management of the "activation time" and "cycle time" is the responsibility of the rotating control unit 5, again according to instructions from the Icing Protection Control Unit 7.Therefore, the act of transmitting these last two quantities in particular to the control unit. rotating part 5 mounted on rotating part 3 is necessary for the proper functioning of the de-icing system of turboprop 100.

[0012] Similarly, the rotating control unit 5 must transmit a "health status" of the defrosting system equipment 1 installed in the rotating section (rotating control unit 5, heating mats 9, etc.) to the frost protection control unit 7. This information is essential for performing reconfigurations if a fault is detected.

[0013] Currently, in order to perform these bidirectional data transfers (upstream and downstream) as well as power transfers, a device called a slip ring is used. This device consists of several fixed conductive rings rubbing against circular conductive tracks attached to the rotating part of the turbomachine. A weakness of this device is its limited lifespan due to wear of the continuously rubbing parts. This implies frequent periodic maintenance and therefore significant operating costs for an aircraft such as a commercial airliner with a high number of rotations.

[0014] Another proposed solution is to perform contactless data transfers by magnetic induction by superimposing a high-frequency, low-energy signal onto the power signal (of the type used in power line communication technology). This solution is complex to implement due to the constraints related to managing interference between the two superimposed signals on the one hand, and the risk of corruption of the transmitted data on the other. Indeed, a turboprop engine contains a multitude of sources of interference: the presence of transients related to load switching in the rotating control unit, the large air gap of the rotary transformer, and variations in the air gap due to radial and axial displacements.

[0015] These problems are partly solved by using a second auxiliary rotary transformer dedicated to data transfers. Such a solution eliminates interference between communication and power signals, but it is expensive, bulky, and difficult to install on a turbomachine.

[0016] Another proposed solution is the implementation of capacitive data transfer between the rotating and stationary parts. However, this solution is only advantageous for a rotary transformer with a small and controlled air gap, which is not the case for the rotary transformer 8 of the turboprop described above. Description of the invention

[0017] One object of the invention is to provide a method for bidirectional data transfers for piloting and controlling a de-icing system between the fixed part and rotating part that is robust and economical, as well as simple to implement and integrate into a turboprop engine.

[0018] To this end, the invention provides a de-icing method in a turboprop de-icing system comprising a fixed part, a rotating part, and a rotary transformer positioned between the fixed and rotating parts. The fixed part comprises an inverter electrically connected to the rotary transformer and a frost protection control unit connected to the inverter. The rotating part comprises a rotary control unit electrically connected to the rotary transformer and a heating mat. The method comprises the following steps: - Power supply for the heating mat, - Transmission of defrost commands from the frost protection control unit to the rotary control unit, - Communication of the health status of the rotating part from the rotary control unit to the frost protection control unit, the method comprising bidirectional data transfer, the transfer comprising upstream data transfer steps from the rotary control unit to the frost protection control unit and downstream data transfer steps from the frost protection control unit to the rotary control unit, wherein: a. During the downstream data transfer steps, the method includes a step of encoding the downstream data into frequency modulations of a supply voltage provided by the inverter to the rotary transformer around a predetermined nominal frequency of said supply voltage; and, b. during the upstream data transfer steps, the process includes a step of encoding the upstream data into predetermined series of changes in the electrical power consumed by the rotary control unit.

[0019] Advantageously, the defrosting process according to the invention has at least one of the following technical characteristics: • each change in the series of predetermined changes in electrical power lasts either for a so-called "short" duration or for a so-called "long" duration; • The so-called "long" duration is at least double the so-called "short" duration, preferably at least triple. • changes in electrical power consumption are predetermined decreases in electrical power; • the rotary control unit including an anti-icing device, drops in electrical power are interruptions of predetermined durations of a power supply to the anti-icing device; • changes in electrical power consumption are predetermined increases in electrical power; • the rotary control unit having a dedicated electrical circuit, increases in electrical power are activations of predetermined durations of the dedicated electrical circuit; • the dedicated electrical circuit is one of resistive, capacitive and resistive-capacitive circuits; • Frequency modulations include a predetermined high frequency value greater than a nominal frequency value, and a predetermined low frequency value less than the nominal frequency value; • frequency modulations are less than or equal to approximately 200 Hz, or even 100 Hz, around the nominal frequency; • The frequency modulations are sent to the inverter, which implements them; and, • a downward data transfer step and an upward data transfer step are carried out simultaneously.

[0020] The invention also provides for a turboprop engine comprising a de-icing system, a fixed part, a rotating part and a rotary transformer positioned between the fixed and rotating parts, the fixed part comprising an inverter electrically connected to the rotary transformer and a frost protection control unit connected to the inverter, the rotating part comprising a rotary control unit electrically connected to the rotary transformer and a heating mat, in which the rotary control unit, the inverter and the frost protection control unit are arranged so as to implement a de-icing process in a de-icing system having at least one of the preceding technical characteristics. brief description of the figures

[0021] Other features and advantages of the invention will become apparent from the following description of an embodiment of the invention. See the accompanying drawings:

[0022] [Fig-1] is a schematic diagram of a turboprop de-icing system in which is implemented a bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention;

[0023] [Fig.2] is a timing diagram illustrating an example of downward data transfer with the bidirectional data transfer method for piloting and controlling a turboprop de-icing system;

[0024] [Fig.3] is a timing diagram illustrating a first example of upward data transfer with the bidirectional data transfer method for piloting and controlling a turboprop de-icing system; and,

[0025] [Fig.4] is a timing diagram illustrating a second example of upstream data transfer with the bidirectional data transfer method for piloting and controlling a turboprop de-icing system.

[0026] For clarity, identical or similar elements are identified by identical reference numerals throughout the figures, detailed description of an embodiment

[0027] With reference to [Fig.1], we will resume the description of the de-icing system 1 of a turboprop 100 in which a bidirectional data transfer method for piloting and controlling a de-icing system of a turboprop according to the invention is implemented.

[0028] Within the stationary section, the inverter 4 therefore includes a DC / AC converter 40 which is supplied upstream with direct current by a high-voltage direct current supply 6 and which supplies downstream with alternating current to the stationary primary winding of the rotary transformer 8. The DC / AC converter 40 provides alternating current with a predetermined nominal frequency at a given supply voltage. This predetermined nominal frequency is chosen according to the structure of the turboprop 100 in which the de-icing system 1 is intended to be installed. The power level to be transferred and the thermal constraints of the equipment integration area are important criteria in determining the nominal frequency.

[0029] On the other hand, the inverter 4 includes an inverter supervisor 41 which controls and manages the operation of said inverter 4 and, in particular, the DC / AC converter 40. The inverter supervisor 41 is connected to the frost protection control unit 7 from which it receives instructions and to which it sends operating data.

[0030] In particular, the inverter supervisor 41 drives the DC / AC converter 40 to send control data to the rotating control unit 5. To this end, the inverter supervisor 41 implements downlink data transfer steps of the bidirectional data transfer method for driving and controlling a turboprop de-icing system according to the invention. The inverter supervisor 41 then encodes the downlink control data into specific, time-limited data frames. The frames are then transmitted to The rotating control unit 5, after an encoding module 42 of the inverter supervisor 41, encodes the frames into frequency modulations of the AC supply voltage around the predetermined nominal frequency of said supply voltage. Here, the frequency modulations use three distinct frequency values.

[0031] The first frequency value is the predetermined nominal frequency value. This value corresponds to a "NULL" data point, fixed at F_NULL (example 1500Hz) and means that there is no data transmission, only power.

[0032] The second frequency value is a value set to F_LOW (e.g., 1400 Hz) to generate a Boolean value of "0". The second frequency value is lower than the predetermined nominal frequency value, here approximately 100 Hz lower. Other difference values ​​can be used, such as approximately 200 Hz lower. In any case, this difference value must be chosen to provide sufficient separation from the first frequency value to protect downstream data transfers against potential external interference.

[0033] The third frequency value is a value set to F_HIGH (e.g., 1600 Hz) to generate a Boolean value of "1". This third frequency value is higher than the predetermined nominal frequency value, here approximately 100 Hz higher. Again, other difference values ​​can be used, such as approximately 200 Hz higher. In any case, this difference value must be chosen to provide sufficient separation from the first value to protect downstream data transfers against potential external interference. It should be noted that here, the difference in values ​​is symmetrical to the previously mentioned difference between the first and second frequency values. Alternatively, they can be inverted or asymmetrical.

[0034] The frequency modulations thus generated to encode the downlink data frames are transmitted to the rotating part 3 through the rotary transformer 8.

[0035] The rotating part 3 of the turboprop 100 includes the rotating control unit 5 as well as the set of heating mats 9, the supply of which is managed in a manner known per se by the rotating control unit 5.

[0036] In order to decode the downstream data frames received from the rotary transformer 8, the rotating control unit 5 includes a module for decoding the frequency modulations of the supply voltage emitted by the rotary transformer 8 to the rotating control unit 5. The decoding module includes a means for measuring the supply voltage 52 provided by the rotating secondary winding of the rotary transformer 8. The measurements thus taken by the voltage measuring means 52 are sent to a frequency modulation decoder 53. The downlink data thus decoded by the frequency modulation decoder 53 is sent to a rotating control unit supervisor 51. The rotating control unit supervisor 51 drives and controls, according to the received downlink data, a power switch 57 which will allow the distribution of the power received from the rotary transformer 8 to the different rotating belts 9. For this purpose, the power switch 57 includes a defrosting switch 571 controlled by the rotating control unit supervisor 51 via a control module 54 of the defrosting switch 571.

[0037] An example of downlink data frames T1 and T2 is illustrated in [Fig. 2]. The second and third frequency values ​​mentioned above are used by the encoding module 42 and the decoding module for a predetermined duration C. Thus, in [Fig. 2], the downlink data frame T1 contains the message "010110", then a predetermined minimum spacing time W elapses during which the supply voltage returns to the first value corresponding to the predetermined nominal frequency and therefore to the transmission of no data. Then the downlink data frame T2 is transmitted and is identical to the downlink data frame T1, namely the message "010110".

[0038] Each downstream data frame is, here for illustrative purposes, encoded on six bits: four bits dedicated to the downstream data and two check bits. The duration C of a Boolean "0" or "1" is defined by ten cycles at the corresponding frequency. With this choice, each downstream data frame has a transfer time of approximately 35 to 45 ms. It should be noted that the number of downstream data frames, the size of each downstream data frame, the number of cycles for a Boolean, and the number of retransmissions of a frame are a non-limiting example of an implementation and are given here purely for illustrative purposes. Other choices are possible.

[0039] To enable synchronization between the frost protection control unit 7 and the rotating control unit 5, as well as the delimitation of a downlink data frame in time, each downlink data frame is delimited at the beginning and end by a transmission in "NULL" mode (first frequency value) as illustrated in [Fig. 2]. Thus, the beginning of a downlink data frame is detected by the transition from a "NULL" state (first frequency value) to an active state "0" (second frequency value) or "1" (third frequency value), while the end is detected by the transition from an active state "0" (second frequency value) or "1" (third frequency value) to the "NULL" state (first frequency value).

[0040] For safety reasons, the transmission of each downstream data frame is repeated with a pause of the spacing duration W (example: 1 second). This repetition, or another number of successive transmissions of the data frames, serves to strengthen the communication. The retransmissions can be maintained for the entire activation time of a set of heating mats 9 or limited to a predetermined fixed number of retransmissions of each downstream data frame.

[0041] Now we will describe the operation of the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention allowing upstream data transfer between the rotating control unit 5 and the anti-icing protection control unit 7.

[0042] Within the rotating part 3 of the turboprop 100, the power switch 57 includes an anti-icing switch 572 controlled by the rotating control unit supervisor 51 via an upstream data encoding device 55 and an interrupt control module 56. On the other hand, the rotating control unit supervisor 51 receives status and operating information 50 and 90 respectively from the rotating control unit 5 itself and the heating mats 9. It is essentially this status and operating information that will be sent to the anti-icing control unit 7 by the rotating control unit 5 via upstream data transfers.

[0043] In an alternative embodiment, if the defrosting system 1 does not include anti-icing, the anti-icing switch 572 is replaced by a dedicated electrical circuit that is either resistive, capacitive, or resistive-capacitive. Alternatively, the dedicated electrical circuit is preferably mounted upstream of the power switch 57. In yet another embodiment of the defrosting system 1, the latter includes both the dedicated electrical circuit and the anti-icing. In this case, the upstream data encoding is performed using the dedicated electrical circuit.

[0044] For the transfer of upstream data from the rotating control unit 5 to the anti-icing control unit 7, the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention includes a step of encoding the upstream data into predetermined series of changes in the power consumed by the rotating control unit 5. The principle of encoding this upstream data is based on a modulation of the amplitude of the current consumed by the heating mats 9 through the rotating control unit 5 in a Morse type manner, by introducing interruptions on a power supply of the anti-icing which represents approximately 15% of the total consumption passing through the rotating control unit 5.

[0045] Thus, the rotating control unit 5, in order to send upstream data to the frost protection control unit 7, commands the interrupt control module 56 to activate / deactivate the anti-icing switch 572 over well-defined predetermined durations. This allows the current consumption to be modulated by introducing predetermined changes in the electrical power consumed by the rotating control unit 5. In the stationary part 2 of the turboprop 100, the inverter supervisor 41 measures, on the one hand, the current I and, on the other hand, the voltage V, here upstream of the DC / AC converter 40 via a power estimator 45. The upstream data is then decoded by an upstream data decoding module 46 from the power variations estimated by the power estimator 45. The upstream data thus decoded is sent by the inverter supervisor 41 to the frost protection control unit 7.

[0046] The bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention encodes the uplink data to be transferred into predefined and unique uplink data frames, each consisting of a series of changes in electrical power consumed from anti-icing activation / deactivation sequences over well-defined durations.

[0047] Two types of sequence are envisaged: a sequence of so-called "short" duration (10ms for example) and a sequence of so-called "long" duration (30ms for example). Each sequence, whether short or long, is delimited by a predefined "pause" duration before and after (set at 10ms for example).

[0048] To enable synchronization between the inverter supervisor 41 and the rotating control unit 5, as well as delimitation of an upstream data frame in time, each upstream data frame is delimited at the beginning and end by a transmission in "NULL" mode as illustrated in Figures 3 and 4. Thus, the beginning of an upstream data frame is detected by the transition from a "NULL" state to a different "ON" or "OFF" state, while the end is detected by the transition from an active "ON" or "OFF" state to the "NULL" state.

[0049] An example of encoding an uplink data frame by the rotating control unit 5 is illustrated in [Fig. 3]. In this encoding embodiment, the changes in electrical power are predetermined drops in the electrical power consumed. Indeed, when the anti-icing system is in operation, the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention interrupts the anti-icing power supply for predefined durations, depending on the types of encoded sequences mentioned above. The uplink data frame illustrated in [Fig. 3] contains the message "long, short, short, long", which can be translated into boolean as "1001".

[0050] Another example of encoding an uplink data frame by the rotating control unit 5 is illustrated in [Fig. 4]. In this alternative encoding embodiment, the changes in electrical power are predetermined increases in the electrical power consumed. Since the anti-icing system is not in operation, the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention activates the anti-icing system power supply for predefined durations based on the previously mentioned types of encoded sequences. The uplink data frame illustrated in [Fig. 4] contains the message "long, short, long, short," which can be translated into Boolean by "1010."This encoding embodiment is also used if the rotating control unit 5 includes the dedicated electrical circuit: indeed, in this case, the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention carries out activations of predefined durations depending on the types of encoded sequences mentioned above, of the power supply to the dedicated electrical circuit.

[0051] Each uplink data frame is, here for illustrative purposes, encoded on "four bits," that is, a series of four sequences of short and / or long duration. The long duration is three times the short duration. With this choice, each uplink data frame has a transfer time of approximately 70 to 110 ms. It should be noted that the number of uplink data frames, the size of each uplink data frame, and the lengths of the short and long durations are a non-limiting example of an embodiment and are given here purely for illustrative purposes. Other choices are possible. For example, the long duration could be at least twice the short duration, thus reducing the size of the uplink data frames.

[0052] Generally, upstream data transfers depend on the presence of the anti-icing function. To make the solution independent and thus robust to changes in the de-icing system 1, such as the possible removal of the anti-icing function in the rotating part 3, a dedicated circuit, as previously mentioned, is implemented; connected in parallel. It must be designed with a power consumption level compatible with the accuracy of the sensors of the power estimator 45 located in the fixed part 2 to facilitate the detection of power changes and thus enable the decoding of the upstream data frames sent. Advantageously, this alternative makes the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention independent of the anti-icing load and therefore independent of the powered system. Advantageously Furthermore, it allows for increased communication throughput without interfering with the performance of the anti-icing system. Indeed, power interruptions to the anti-icing system must remain compatible with its proper operation and result in uplink data frames of longer durations than can be accommodated by using the dedicated electrical circuit.

[0053] On the other hand, the use of the activation / deactivation of the anti-icing (and therefore of the power it consumes) independently of the defrosting system 1 on the principle of Morse code makes it possible to communicate information from the rotating part to the fixed part without being constrained by considerations of the performance of the anti-icing system.

[0054] It should be noted that the bidirectional data transfer method for piloting and controlling a turboprop de-icing system allows for upstream data transfer at the same time as downstream data transfer without interference between the two transfers.

[0055] The use of the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention described above provides an efficient, robust, low-cost, and easy-to-implement communication solution. The bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention allows for flexibility in signal modulation without altering the power transfer function, and offers low implementation costs compared to other prior art solutions requiring additional equipment. Furthermore, the bidirectional data transfer method for piloting and controlling a turboprop de-icing system according to the invention is applicable regardless of the type of DC / AC topology (voltage, nominal frequency) and the rotary transformer 8.

[0056] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

[0057] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances render such combinations impossible or meaningless.

Claims

1. Demands De-icing method in a de-icing system (1) of a turboprop engine (100) comprising a fixed part (2), a rotating part (3) and a rotary transformer (8) positioned between the fixed and rotating parts, the fixed part comprising an inverter (4) electrically connected to the rotary transformer and an anti-icing control unit (7) connected to the inverter, the rotating part comprising a rotary control unit (5) electrically connected to the rotary transformer and a heating mat (9), the method comprising the steps of: - Power supply for the heating mat, - Transmission of defrost commands from the frost protection control unit to the rotary control unit, - Communication of the rotating part's health status from the rotary control unit to the frost protection control unit, characterized in that the method comprises a bidirectional data transfer, the transfer comprising upstream data transfer steps from the rotary control unit to the frost protection control unit and downstream data transfer steps from the frost protection control unit to the rotary control unit, wherein: a. during the downlink data transfer steps, the method includes a step of encoding the downlink data into frequency modulations of a supply voltage provided by the inverter to the rotary transformer around a predetermined nominal frequency of said supply voltage; and, b. during the uplink data transfer steps, the method includes a step of encoding the uplink data into predetermined series of changes in an electrical power consumed by the rotary control unit.

2. A method according to claim 1, wherein each change in the series of predetermined changes in electrical power lasts either for a so-called "short" duration or for a so-called "long" duration.

3. A method according to claim 2, wherein the so-called "long" duration is at least double the so-called "short" duration, preferably at least triple.

4. A method according to any one of claims 1 to 3, wherein the changes in electrical power consumed are predetermined drops in electrical power.

5. A method according to claim 4, wherein, the rotary control unit comprising an anti-icing device, drops in electrical power are interruptions of predetermined durations of a power supply to the anti-icing device.

6. A method according to any one of claims 1 to 3, wherein the changes in electrical power consumed are predetermined increases in electrical power.

7. A method according to claim 6, wherein, the rotary control unit having a dedicated electrical circuit, the increases in electrical power are activations of predetermined durations of the dedicated electrical circuit.

8. Method according to claim 7, wherein the dedicated electrical circuit is one of resistive, capacitive and resistive-capacitive circuits.

9. A method according to any one of claims 1 to 8, wherein the frequency modulations include a predetermined high frequency value greater than a nominal frequency value, and a predetermined low frequency value less than the nominal frequency value.

10. A method according to any one of claims 1 to 9, wherein the frequency modulations are less than or equal to about 200 Hz, or even 100 Hz, around the nominal frequency.

11. A method according to any one of claims 1 to 10, wherein the frequency modulations are sent to the inverter which implements them.

12. A method according to any one of claims 1 to 11, wherein a downward data transfer step and an upward data transfer step are carried out simultaneously.

13. Turbopropeller (100) comprising a de-icing system (1), a fixed part (2), a rotating part (3) and a transformer rotary (8) positioned between the fixed and rotating parts, the fixed part comprising an inverter (4) electrically connected to the rotary transformer and a frost protection control unit (7) connected to the inverter, the rotating part comprising a rotary control unit (5) electrically connected to the rotary transformer, wherein the rotary control unit, the inverter and the frost protection control unit are arranged so as to implement a defrosting process in a defrosting system according to any one of claims 1 to 12.

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