System for de-icing the blades of the propeller of an aircraft comprising a primary measurement winding

Abstract

The invention relates to a system (10) for de-icing the blades (14) of the propeller (12) of an aircraft, the system comprising an H-bridge inverter device (40); a rotary transformer (22) comprising a main primary winding (26), a primary measurement winding (28), and a secondary circuit (30) delivering a secondary alternating voltage (Vs); a rectifier device (50); a de-icing device (20); a control device (60) configured to control the switching elements of the inverter device in an out-of-phase manner, using the value of the voltage (Vpm) across the terminals of the primary measurement winding, measured during a measurement interval of predetermined duration starting at the instant (t11,t33) when the inverter device switches from a controlled state to a short-circuit state.

Description

[0001] Description

[0002] Title of the invention: Aircraft propeller blade de-icing system comprising a primary winding for measuring

[0003] Technical Field

[0004] The present invention relates to the technical field of de-icing systems for aircraft propeller blades equipped with de-icing devices. De-icing devices traditionally comprise a set of electric heating mats associated with the propeller blades, which prevent ice from forming on said blades.

[0005] Within the aircraft, the de-icing system is rotationally linked to the rotor blades and therefore to the aircraft's propeller, and is thus positioned within the rotating frame of reference. It is therefore necessary to implement solutions to provide electrical power to the de-icing system and to control the voltage and power supplied to it.

[0006] Previous technique

[0007] Systems exist that provide electrical power to the aircraft's de-icing device, located in the rotating frame, using a brush-type commutator. However, these devices wear out very quickly, resulting in a limited lifespan and requiring regular maintenance.

[0008] Prior art document EP3845458B1 describes a power supply solution for a helicopter blade de-icing system. In this document, the heating mats are powered with alternating current (AC), which is unsuitable for the present application. Supplying the de-icing system with AC imposes significant constraints on the insulation of the heating mats. As an alternative, this document considers the use of a flyback converter. However, this converter is also unsuitable for the present high-power application due to the substantial losses it generates. Furthermore, this type of converter is not designed to operate in a harsh thermal environment, such as that found in an aircraft.

[0009] Furthermore, while the use of rotating transformers has been considered in the prior art, its implementation remains complex. Indeed, using a rotating transformer makes regulating the DC supply voltage to the defrosting device difficult, given the challenge of measuring this voltage in the rotating frame and transmitting it to the controller located in the fixed frame. In particular, using a rectifier in the rotating frame does not allow for measuring the DC supply voltage to the defrosting device at every instant. Controlling this DC supply voltage to the defrosting device is therefore particularly complex. Specifically, the DC supply voltage must not exceed the operating limits of the defrosting device to avoid damaging it and its heating mats.This limitation proves problematic given the difficulties in efficiently transmitting a measurement of this DC supply voltage from the rotating reference frame to the controller in the fixed reference frame.

[0010] Description of the invention

[0011] One aim of the present invention is to provide a system for de-icing the propeller blades of an aircraft which remedies the aforementioned drawbacks.

[0012] To this end, the invention relates to a system for de-icing the propeller blades of an aircraft, said propeller being rotationally linked to a rotating drive element of the aircraft configured to be driven by a turbomachine of the aircraft, the system comprising: a controllable H-bridge type inverter device having a first input terminal and a second input terminal configured to be connected to a DC power supply of the aircraft, as well as a first output terminal and a second output terminal, the inverter device being configured to deliver a primary AC voltage from a DC voltage delivered by the DC power supply;a rotating transformer comprising: a primary winding fixed relative to a portion of the aircraft frame and connected between the first and second output terminals of the inverter device, so that it receives said primary alternating voltage delivered by said inverter device; a primary measuring winding magnetically coupled to the primary winding and fixed relative to said portion of the aircraft frame; a secondary circuit rotationally linked to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled to the primary winding in order to deliver a secondary alternating voltage from the primary alternating voltage received by said primary winding;a rectifier device connected to said secondary circuit of the rotating transformer and configured to deliver a DC supply voltage from said secondary AC voltage, the rectifier device comprising a rectifier element having two output terminals and a filter capacitor connected between said output terminals of the rectifier element; a de-icing device configured to de-ice the propeller blades, the de-icing device being connected to the rectifier device so that it receives said DC supply voltage;an inverter device control device configured to control said inverter device in a phase-shifted manner, such that said inverter device describes at least one control cycle during which it takes at least one controlled state in which it delivers a positive or negative voltage and then a short-circuit state in which the voltage it delivers is zero, the control device being configured to control the inverter device using the value of the voltage across the primary measuring winding measured during a measurement interval of predetermined duration and which begins at the instant when the inverter device transitions from a controlled state to a short-circuit state.;

[0013] The de-icing device is advantageously rotationally linked to the rotating drive element and to the aircraft propeller. The de-icing device advantageously includes a de-icing means, for example, a set of heating mats.

[0014] The rotating transformer of the system according to the invention exhibits reduced wear and maintenance requirements compared to a brushed commutator. According to the invention, the defrosting device is powered by direct current, which reduces the insulation requirements for the heating mats compared to solutions that power the defrosting device with alternating current.

[0015] The main primary winding of the rotating transformer advantageously comprises a plurality of turns. The main primary winding and the primary measuring winding are arranged in the fixed coordinate system. The secondary circuit of the rotating transformer is arranged in the rotating coordinate system.

[0016] The main primary winding and the measuring primary winding define a primary circuit for the rotating transformer. They are separate and magnetically coupled. The rotating transformer may, but are not limited to, include multiple main primary windings. Only the main primary winding(s) and the secondary circuit contribute to the transfer of energy from the fixed reference frame to the rotating reference frame. The measuring primary winding is solely for voltage measurement and does not contribute to energy transfer.

[0017] The primary measuring winding is advantageously arranged in parallel with the main primary winding, on the same magnetic circuit in the stationary section. The primary measuring winding is advantageously galvanically isolated from the main primary winding. The primary measuring winding is advantageously galvanically isolated from the secondary circuit. The primary measuring winding advantageously comprises at least one turn, preferably two turns.

[0018] Preferably, the secondary circuit of the rotating transformer comprises at least one secondary winding. Even more preferably, but not limitingly, the secondary circuit comprises a first secondary winding and a second secondary winding connected in series with the first secondary winding. Advantageously, the first and second secondary windings are connected together at a central node, said central node being connected to a ground line.

[0019] The rectifier device imposes the specified DC supply voltage on the defrosting device. This rectifier may, but is not limited to, comprise a diode bridge or a synchronous rectifier including a plurality of MOSFET transistors. The output terminals of the rectifier device are advantageously connected to the defrosting device. The filter capacitor is configured to impose the specified DC supply voltage on the defrosting device. The filter capacitor presents the specified DC supply voltage across its terminals. The filter capacitor is advantageously connected between the output terminals of the rectifier device. The output terminals of the rectifier device advantageously correspond to the output terminals of the rectifier device.

[0020] The inverter device is configured to deliver the primary alternating voltage from the direct current voltage supplied by the direct current power source. Advantageously, the inverter device is fixed relative to the aircraft frame and is therefore located in the fixed frame.

[0021] The inverter device advantageously comprises a plurality of controllable switching elements capable of assuming a blocked state and a conducting state. The control device is advantageously configured to control said switching elements.

[0022] The control device is advantageously configured to regulate the power supplied to the defrosting unit. The control device also controls the inverter to supply power to the transformer.

[0023] The control device is configured to operate the H-bridge inverter according to a phase-shift control method, the principle of which is well known to those skilled in the art. This type of control is also called "phase shift" in English. It differs from a symmetrical control method. The use, according to the invention, of an inverter controlled by a phase-shift method reduces losses within the system and therefore its heating. The system according to the invention is thus particularly well-suited for integration into an aircraft where the thermal environment is harsh.

[0024] The control device is advantageously configured to control the inverter device so that it performs a plurality of successive control cycles. The control cycles advantageously all have the same period. Advantageously, the inverter device is capable of assuming an active state in which it is controlled to perform one or more successive control cycles.

[0025] The sum of all positive and negative voltages delivered during the phases when the inverter is in the controlled state, and all zero voltages delivered during the phases when the inverter is in the short-circuit state, constitutes the primary AC voltage delivered by the inverter. It is understood that the instant at which the measurement interval begins corresponds to the instant when the inverter transitions from one of these controlled states to one of these short-circuit states.

[0026] More precisely, when the inverter transitions from a controlled state to a short-circuit state, the transformer's main primary winding is short-circuited, and the voltage delivered by the inverter drops to zero almost instantaneously, if the switching time of the switching elements is neglected. In contrast, the voltage across the secondary circuit of the rotating transformer does not drop to zero immediately but only after a certain time. This delay is due to the current stored in the rotating transformer's leakage inductances, which discharge gradually.

[0027] This results in a period during which the voltage delivered by the inverter is zero, while the voltage across the secondary circuit of the rotating transformer is always positive or negative. Furthermore, during this period, the secondary AC voltage across the secondary circuit has an amplitude equal to that of the DC supply voltage provided to the defrosting device, which is advantageously controlled by the filter capacitor of the rectifier.

[0028] The measurement interval is selected within this period, such that the voltage across the primary winding is measured after the inverter transitions from a controlled to a short-circuited state, but before the secondary AC voltage drops to zero. Without limitation, this measurement of the voltage across the primary winding may be taken at the instant the inverter transitions from a controlled to a short-circuited state, or at any time after that instant, within the measurement interval.

[0029] Each control cycle generates at least one measurement interval, preferably two measurement intervals, allowing the value of the voltage across the terminals of the primary measuring winding to be measured.

[0030] The predetermined duration of the measurement interval is advantageously chosen according to the nature of the rotating transformer. Preferably, this predetermined duration of the measurement interval is chosen to be shorter than a known time after which the leakage inductances of the rotating transformer are completely discharged. Preferably, the voltage across the primary measuring winding is measured while the inverter device is in a short-circuited state. In other words, the measurement interval is chosen to correspond to a period during which the inverter device is in a short-circuited state. Preferably, the voltage across the primary measuring winding is measured before the inverter device enters a new controlled state.

[0031] Calculations performed using simplifying assumptions demonstrate that, during this measurement interval, there is a proportional relationship between the DC supply voltage provided to the defrosting device and the voltage across the primary measuring winding. The DC supply voltage is therefore a function of the voltage across the primary measuring winding. In other words, during this measurement interval, the voltage across the primary measuring winding reflects the DC supply voltage.

[0032] Therefore, the present invention proposes using a measurement of this voltage across the terminals of the primary measuring winding, easily taken in the fixed frame, as a representation of the DC supply voltage provided to the defrosting device in the rotating frame. The invention thus allows the inverter device to be controlled and, advantageously, the voltage and power supplied to the defrosting device to be monitored, using said measurement of the voltage across the terminals of the primary measuring winding. The invention eliminates the need to measure the DC supply voltage in the rotating frame and the difficulties of transferring such a measurement from the rotating frame to the fixed frame.

[0033] In other words, according to the invention, the primary measuring winding is used as an intermediary to obtain a measurement, taken in the fixed reference frame, of the continuous supply voltage of the defrosting device.

[0034] Without limitation, the control device can be configured to control the inverter device, using said measurement of the voltage across the terminals of the primary measuring winding, in order to regulate the voltage across the terminals of the primary measuring winding, to regulate the DC supply voltage, or to limit said DC supply voltage below a limiting threshold.

[0035] Preferably, the control device is configured to determine said DC supply voltage delivered by the rectifier device as a function of said voltage across the primary winding of measurement measured during said measurement interval.

[0036] Without limitation, the voltage across the primary winding can be measured at any time during the measurement interval. Preferably, the system includes a measuring device configured to measure the voltage across the primary winding.

[0037] Preferably, the control device is configured to control the inverter device so that the latter alternately and sequentially takes a controlled state and then a short-circuit state.

[0038] Preferably, but not exclusively, the control device is configured to control the inverter device so that during said control cycle the latter successively takes a first controlled state, a first short-circuit state, a second controlled state and then a second short-circuit state.

[0039] It is understood that the said instant at which the measurement interval begins corresponds to the instant when the inverter device passes from the first controlled state to the first short-circuit state or to the instant when it passes from the second controlled state to the second short-circuit state.

[0040] The measurement of the voltage value across the terminals of the primary measuring winding is advantageously synchronized with said measuring interval.

[0041] Preferably, the voltage across the primary winding is measured after a delay following the instant the inverter device transitions from a controlled state to a short-circuit state. This measurement delay improves measurement quality by preventing interference from the switching of the switching elements.

[0042] Advantageously, the inverter device comprises a first arm in which are connected a first controllable switching element disposed between the first input terminal and the first output terminal and a second controllable switching element disposed between the second input terminal and the first output terminal, the inverter device further comprising a second arm in which are connected a third controllable switching element disposed between the first input terminal and the second output terminal and a fourth controllable switching element disposed between the second input terminal and the second output terminal, each of said controllable switching elements being able to take at least one blocked state and one conducting state, the control device being configured to control the switching elements of the second arm of the inverter device in a phase-shifted manner with respect to the switching elements of the first arm.

[0043] In the off state, the switching elements of the inverter behave like open switches, preventing current flow. In the on state, the switching elements behave like closed switches and allow a non-zero current to flow through them. Preferably, but not exclusively, the switching elements of the inverter include a transistor, for example, a MOSFET.

[0044] The control unit manages all the switching elements of the inverter. The control unit also supplies power to the transformer.

[0045] According to phase-shifted control, also called offset control, the third and fourth switching elements are controlled out of phase with respect to the first and second switching elements.

[0046] In said at least one controlled state, the first and fourth switching elements are in the conducting state while the second and third switching elements are in the blocking state, in which case said voltage delivered by the inverter device is positive, preferably of constant amplitude; or the second and third switching elements are in the conducting state while the first and fourth switching elements are in the blocking state, in which case the voltage delivered by the inverter device is negative, preferably of constant amplitude.

[0047] In at least one short-circuit state, the first and third switching elements are in the conducting state while the second and fourth switching elements are in the blocking state, or the second and fourth switching elements are in the conducting state while the first and third switching elements are in the blocking state. The voltage delivered by the inverter device is then zero.

[0048] Preferably, but not exclusively, the control device is configured to control the switching elements of the inverter device so that during said control cycle the latter successively takes a first controlled state, a first short-circuit state, a second controlled state and then a second short-circuit state.

[0049] In the first controlled state, the first and fourth switching elements are in the conducting state, while the second and third switching elements are in the blocked state. In the first short-circuit state, the second and fourth switching elements are in the conducting state, while the first and third switching elements are in the blocked state. In the second controlled state, the second and third switching elements are in the conducting state, while the first and fourth switching elements are in the blocked state. In the second short-circuit state, the first and third switching elements are in the conducting state, while the second and fourth switching elements are in the blocked state.

[0050] Advantageously, said rectifier unit comprises a diode bridge having two input terminals connected to said secondary circuit and two output terminals connected to the defrosting device, the filter capacitor being connected between the output terminals of the diode bridge.

[0051] When the inverter is in a controlled state, the rotating transformer supplies current to the rectifier, and its diodes are conducting. Following a short-circuit state of the inverter, the leakage inductances of the rotating transformer gradually discharge, and the diodes of the rectifier remain conducting until the current supplied by the rotating transformer drops to zero, at which point the diodes become reverse-biased and the secondary AC voltage is zero.

[0052] Advantageously, the inverter device comprises a first arm in which first and second switching elements are connected and a second arm in which third and fourth switching elements are connected, the control device comprising a control unit configured to control the inverter device at least from a control setpoint, said control unit comprising a voltage control module configured to generate a phase angle setpoint between the switching elements of the first and second arms from said control setpoint of the switching elements, the control unit further comprising a control signal generation module configured to generate control signals to the switching elements of the inverter device as a function of said phase angle setpoint.The phase angle defines the phase difference between the switching of the switching elements of the first arm and those of the second arm. The duration for which the inverter device is maintained in a controlled state and in a short-circuit state depends directly on this phase angle.

[0053] Said control unit is advantageously configured to control the switching elements of the first arm and second arm of the inverter device from said control setpoint.

[0054] The control setpoint is advantageously determined by means of a power regulation loop or a voltage regulation loop. In other words, the control unit advantageously implements voltage regulation or power regulation. Preferably, the control unit is configured to determine the control setpoint by means of a voltage regulation loop, using the voltage across the primary winding measured over a predetermined measurement interval that begins the instant the inverter device transitions from a controlled state to a short-circuit state.

[0055] The control device advantageously includes a power control module configured to generate the control setpoint. The power control module is advantageously configured to regulate the power supplied to the defrosting device. The power control module is advantageously configured to deliver the control setpoint based on a measurement of the power supplied to the defrosting device and a power setpoint to be supplied to the defrosting device.

[0056] Preferably, the control device is configured to control the inverter device in such a way as to limit the DC supply voltage delivered by the rectifier device below a predetermined maximum voltage threshold.

[0057] It is understood that the control device is configured to limit the DC supply voltage by using the voltage measurement across the primary measuring winding. This voltage limitation is thus facilitated and made more precise, thereby reducing the risk of damage to the defrosting device. Preferably, but not exclusively, the control device is configured to limit the voltage across the primary measuring winding below a predetermined upper measuring voltage threshold. Preferably, the predetermined upper voltage threshold is a function of the characteristics of the defrosting device and preferably corresponds to a limit beyond which the DC supply voltage risks damaging the defrosting device.This measurement threshold is advantageously chosen so as to maintain the continuous supply voltage provided to the defrosting device below the predetermined maximum voltage threshold.

[0058] Advantageously, the control device includes a control unit configured to control the inverter device at least from a control setpoint, and the inverter device can take at least one active configuration in which it describes said at least one control cycle and an inhibited configuration in which it does not deliver voltage, the control device further including a limiting module configured to generate an inhibit signal for said control unit when said value of the voltage across the terminals of the primary measuring winding, measured during said measuring interval, exceeds a predetermined upper measuring voltage threshold, said control unit being configured to place the inverter device in said inhibited configuration in response to the generation of said inhibit signal.

[0059] It is understood that in the active configuration, the inverter device takes at least one controlled state followed by a short-circuit state, preferably a first controlled state, then a first short-circuit state, then a second controlled state, then a second short-circuit state. Advantageously, in the active configuration, the inverter device undergoes a plurality of successive control cycles. This configuration corresponds to normal operation of the inverter device, enabling the generation of the primary alternating voltage.

[0060] In the inhibited configuration, the inverter is stopped, so it no longer supplies power to the rotating transformer, and current no longer flows through the secondary circuit of the rotating transformer. By putting the inverter in the inhibited configuration, the DC supply voltage delivered by the rectifier is kept below the predetermined upper voltage threshold and tends to decrease over time. As long as the inverter is in the inhibited configuration, the DC supply voltage supplied to the defrosting device gradually decreases. This voltage decrease is due to the discharge of the filter capacitor into the equivalent resistance of the defrosting device. The DC supply voltage is thus maintained or reduced below the predetermined maximum voltage threshold, and the defrosting device is better protected.

[0061] Preferably, in the inhibited configuration, all switching elements of the inverter device are placed in the blocked state.

[0062] Advantageously, when said inverter device is in the inhibited configuration, said control device is configured to periodically place the inverter device in said active configuration during a temporary activation phase of a predetermined duration during which said inverter device describes at least one control cycle, before bringing the inverter device back into the inhibited configuration.

[0063] When in the inhibited configuration, the inverter no longer undergoes any control cycles and therefore no longer transitions from a controlled state to a short-circuit state. While the inverter is in the inhibited configuration, it is no longer possible to measure the voltage across the primary winding during a predetermined measurement interval that begins the instant the inverter transitions from a controlled state to a short-circuit state. Consequently, in this configuration, it is no longer possible to determine the DC supply voltage delivered by the rectifier from a measurement of the voltage across the primary winding.

[0064] Periodically activating the inverter during a temporary activation period artificially generates a control cycle in which the inverter switches from the controlled state to the short-circuited state. This initiates a measurement interval, as previously defined, during which the DC supply voltage is a function of the voltage across the primary winding. This allows for the measurement of the voltage across the primary winding, and based on this measurement, the system resumes operation in the active configuration as soon as the voltage across the defrosting device returns to a normal and / or acceptable level.

[0065] According to an advantageous variant, the activation period during which the inverter device is periodically placed in the active configuration during a temporary activation phase is a multiple of the period of the primary AC voltage delivered by said inverter device.

[0066] According to another advantageous variant, the activation period, denoted TM, during which the inverter device is periodically placed in the active configuration during a temporary activation phase, satisfies the equation:

[0067] TM = N xr 40 + y2x r 40 WHERE 40 is the period of the primary alternating voltage delivered by the inverter device and N is a natural integer.

[0068] This activation period reverses the direction of the voltage pulses across the rotating transformer, preventing a slightly unbalanced loading of the transformer's magnetizing inductance. This variation therefore compensates for any potential imbalance in the magnetizing current.

[0069] Preferably, the predetermined duration of the temporary activation phase is equal to the period of the primary AC voltage delivered by the inverter device when it is in its active configuration. During this temporary activation period, the inverter device is placed in the active configuration such that it completes at least one control cycle, preferably a single control cycle. In other words, during the temporary activation period, the inverter device experiences at least one controlled state and one short-circuit state, preferably a first controlled state, a first short-circuit state, a second controlled state, and a second short-circuit state. One advantage is ensuring the generation of at least one measurement interval to guarantee a reliable and robust measurement of the voltage across the primary measuring winding.

[0070] Preferably, the predetermined duration is less than a maximum duration threshold. The maximum duration threshold is chosen so that the predetermined duration is short enough not to supply excessive energy to the rectifier device, and in particular to its filter capacitor, during the temporary activation. This predetermined duration is chosen to be long enough to guarantee a measurement interval sufficient to allow a reliable measurement of the voltage across the primary measuring winding. Preferably, the limiting module is configured to generate an inhibit interrupt signal for the control unit when the voltage across the primary measuring winding, measured during a temporary activation phase, falls within a measurement interval of predetermined duration that begins at time (tn,t). 33) where the inverter device transitions from a controlled state to a short-circuit state, becomes below a predetermined lower measurement voltage threshold, said control unit being configured to place the inverter device in said active configuration in response to the generation of said inhibit interrupt signal.

[0071] Following the inhibition of the inverter device, the voltage across the defrosting device gradually decreases until it falls below a predetermined lower voltage threshold. Simultaneously, the voltage across the primary measuring winding also falls below this predetermined lower voltage threshold. At this point, the inhibition interruption signal is generated, and the inverter device returns to its active configuration, resuming normal operation in which it performs one or more control cycles.

[0072] Advantageously, the energy returned during such an activation phase is low enough not to prevent the voltage from decreasing between two activation phases.

[0073] Preferably, said lower predetermined measurement voltage threshold is determined so as to correspond to a value of the DC supply voltage sufficiently far from the predetermined maximum voltage threshold to allow reactivation of the inverter device without risk of damaging the system.

[0074] The invention also relates to a method for controlling a propeller blade de-icing system of an aircraft, said propeller being rotationally linked to a rotating drive element of the aircraft configured to be driven by a turbomachine of the aircraft, the system comprising: a controllable H-bridge type inverter device having a first input terminal and a second input terminal configured to be connected to a DC power supply of the aircraft, as well as a first output terminal and a second output terminal, the inverter device being configured to deliver a primary AC voltage from a DC voltage delivered by the DC power supply;a rotating transformer comprising: a primary winding fixed relative to a portion of the aircraft frame and connected between the first and second output terminals of the inverter device, so that it receives said primary alternating voltage delivered by said inverter device; a primary measuring winding magnetically coupled to the primary winding and fixed relative to said portion of the aircraft frame; a secondary circuit rotationally linked to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled to the primary winding in order to deliver a secondary alternating voltage from the primary alternating voltage received by said primary winding;a rectifier device connected to said secondary circuit of the rotating transformer and configured to deliver a DC supply voltage from said secondary AC voltage, the rectifier device comprising a rectifier element having two output terminals and a filter capacitor connected between said output terminals of the rectifier element; a de-icing device configured to de-ice the propeller blades, the de-icing device being connected to the rectifier device so that it receives said DC supply voltage;the method comprising the steps in which said inverter device is controlled in a phase-shifted manner, so that said inverter device describes at least one control cycle during which it takes at least one controlled state in which it delivers a positive or negative voltage and then a short-circuit state in which the voltage it delivers is zero, and the inverter device is controlled using the value of the voltage across the primary measuring winding measured during a measurement interval of predetermined duration and which begins at the instant when the inverter device passes from a controlled state to a short-circuit state.;

[0075] Advantageously, the inverter device is controlled in such a way as to limit the DC supply voltage delivered by the rectifier device below a predetermined maximum voltage threshold.

[0076] Advantageously, the inverter device comprises a first arm in which are connected a first controllable switching element disposed between the first input terminal and the first output terminal and a second controllable switching element disposed between the second input terminal and the first output terminal, the inverter device further comprising a second arm in which are connected a third controllable switching element disposed between the first input terminal and the second output terminal and a fourth controllable switching element disposed between the second input terminal and the second output terminal, each of said controllable switching elements being able to take at least one blocked state and one conducting state, and in which the switching elements of the second arm of the inverter device are controlled in a phase-shifted manner with respect to the switching elements of the first arm,based on a set phase angle between the switching elements of the first and second arms.

[0077] Preferably, the inverter device can take at least one active configuration in which it describes said at least one control cycle and an inhibited configuration in which it does not deliver voltage, and an inhibition signal is generated when said value of the voltage across the primary measuring winding, measured during said measuring interval, exceeds a predetermined upper measuring voltage threshold, and in which the inverter device is placed in said inhibited configuration in response to the generation of said inhibition signal.

[0078] Advantageously, when said inverter device is in the inhibited configuration, the inverter device is periodically placed in said active configuration during a temporary activation phase of predetermined duration during which said inverter device describes at least one control cycle, and then the inverter device is brought back into the inhibited configuration.

[0079] Advantageously, during this temporary activation phase, the value of the voltage across the terminals of the primary measuring winding is measured over a measurement interval of predetermined duration, which begins at the instant when the inverter device passes from a controlled state to a short-circuit state.

[0080] The invention also relates to an aircraft comprising a rotary drive element configured to be driven in rotation by a turbomachine of the aircraft; at least one propeller having a plurality of blades, the propeller being rotationally linked to said rotary drive element and a system; and a propeller blade de-icing system as described above.

[0081] Brief description of the drawings

[0082] 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:

[0083] [Fig. 1] Figure 1 shows a system, according to the invention, for de-icing the propeller blades of an aircraft;

[0084] [Fig. 2] Figure 2 shows the control device of the system in Figure 1;

[0085] [Fig. 3] Figure 3 shows a graphical representation of the evolution of the currents and voltages of the primary windings and the secondary circuit of the rotating transformer of the system of Figure 1;

[0086] [Fig. 4] Figure 4 shows an equivalent representation of the rotating transformer of the system in Figure 1;

[0087] [Fig. 5] Figure 5 shows a graphical representation of a procedure for limiting the DC supply voltage to the defrosting device, implemented using the system shown in Figure 1; and

[0088] [Fig.6] Figure 6 is a graphical representation of the evolution of the quantities in Figure 5, during the active configuration of the inverter device.

[0089] Description of the implementation methods

[0090] The invention relates to a system for de-icing the propeller blades of an aircraft.

[0091] Figure 1 shows the de-icing system 10 for the blades 14 of the propeller 12 of an aircraft, according to the invention. In Figure 1, only one blade is shown. The aircraft includes a rotary drive element 16 configured to be driven in rotation, about a drive axis X, by a turbomachine of the aircraft. The rotary drive element 16 defines a rotating frame in which the aircraft's propeller 12 pivots. The aircraft also includes a portion of the aircraft frame 18, defining a fixed frame. The aircraft further includes a DC power supply S configured to deliver a DC voltage V D c- The power supply source S can be a DC bus from the aircraft.

[0092] The system 10 also includes a de-icing device 20. The de-icing device 20 advantageously comprises a set of heating mats 21, each associated with one of the aircraft propeller blades and preventing ice formation on said blade. The de-icing device 20 is rotationally linked to the rotating drive element 16 and is located in the rotating frame.

[0093] The system 10 also includes a rotating transformer 22. The rotating transformer 22 includes a primary circuit 24 comprising a main primary winding 26 and a measuring primary winding 28. The primary circuit 24, and therefore its primary windings 24, 26, are fixed relative to the aircraft frame portion 18, and thus located in the fixed frame. The rotating transformer 22 further includes a secondary circuit 30 comprising, in this non-limiting example, a first secondary winding 32 and a second secondary winding 34 connected in series with the first secondary winding. The first and second secondary windings are connected together at a central node connected to a ground line. The secondary circuit 30, and therefore its secondary windings 32, 34, are rotationally linked to the rotating drive element 16 and are thus located in the rotating frame.

[0094] The system includes a measuring device 36 configured to measure the voltage V pm at the terminals of the primary measuring winding 28.

[0095] The system 10 further includes an inverter device 40 fixed relative to the aircraft frame portion 18 and located in the fixed coordinate system. The inverter device 40 is configured to be connected to the aircraft's power supply S and to the main primary winding 26 of the rotating transformer 22. More specifically, the inverter device 40 includes a first input terminal 40A and a second input terminal 40B connected to the power supply S. The inverter device 40 further includes a first output terminal 40C and a second output terminal 40D between which the main primary winding 26 is connected.

[0096] The inverter device 40 is of the H-bridge type. It comprises a first arm 41 extending between the first and second input terminals 40A, 40B, to which are connected a first controllable switching element 42 and a second controllable switching element 44. The first and second switching elements 42, 44 are separated by a first midpoint Pi connected to the first output terminal 40C. The first switching element 42 is connected between the first input terminal 4OA and the first output terminal 4OC. The second switching element 44 is connected between the second input terminal 4OB and the first output terminal 4OC.

[0097] The inverter device 40 further includes a second arm 45 parallel to the first arm 41, to which are connected a third controllable switching element 46 and a fourth controllable switching element 48. The second and third switching elements 46 and 48 are separated by a second midpoint P2 connected to the second output terminal 40D. The third switching element 46 is connected between the first input terminal 4OA and the second output terminal 4OD. The fourth switching element 48 is connected between the second input terminal 4OB and the second output terminal 4OD.

[0098] In this non-limiting example, the switching elements 42, 44, 46, 48 each comprise a MOSFET-type transistor and an anti-parallel diode and can take a conducting state and a blocking state.

[0099] The inverter device 40 is configured to deliver a primary alternating voltage V pto the main primary winding 26, from said DC voltage V D c is supplied by the DC power source S. The main primary winding 26 therefore presents the primary AC voltage V p at its limits.

[0100] The main primary winding 26 of the rotating transformer 22 is magnetically coupled with the first and second secondary windings 32, 34 so that the secondary circuit 30 delivers a secondary alternating voltage V s from the primary alternating voltage V p across the terminals of the main primary winding 26. The measuring primary winding 28 is magnetically coupled to the main primary winding and does not contribute to energy transfer. The measuring primary winding 28 is dedicated to voltage measurement.

[0101] The system 10 further includes a rectifier device 50 rotatably linked to the rotating drive element 16 and disposed in the rotating frame. The rectifier device 50 includes a diode bridge 52 connected to the secondary circuit 30 of the rotating transformer 22. As is known, the diode bridge 52 comprises four diodes 53 that can be either blocked or conducting depending on the direction of the current. The rectifier device 50 further includes a filter capacitor 54 connected between the output terminals of the diode bridge 52. The rectifier device 50 further includes a resistor 56 connected in parallel with the filter capacitor 54.

[0102] The defrosting device 20 is connected to the output terminals of the rectifier device 50. The rectifier device 50 is configured to deliver a DC supply voltage V a to the defrosting device 20, from said secondary alternating voltage V sdelivered by the rotating transformer 22.

[0103] According to the invention, the system 10 further comprises a control device 60 configured to control the switching elements 42, 44, 46, 48 of the inverter device 40, in order to regulate the DC supply voltage V a supplied by the rectifier device 50 to the defrosting device 20.

[0104] The control device 60 is schematically illustrated in Figure 2. This figure shows that the control device 60 comprises a power control module 62 configured to provide a control setpoint C* based on a power setpoint P* to be supplied to the defrosting device and a power measurement P m supplied to the defrosting device 20. The power control module 62 allows for power regulation of the system and in particular regulation of the power supplied to the defrosting device 20.

[0105] The control device 60 also includes a control unit 64 configured to control the switching elements of the inverter device 40 based, in particular, on said control setpoint C*. The control unit 64 includes a voltage control module 66 configured to deliver a phase angle setpoint 0A, based on said control setpoint C*. The control unit also includes a control signal generation module 68 configured to generate first, second, third, and fourth control signals Si S2, S3, S4 for the first, second, third, and fourth switching elements 42, 44, 46, 48 of the inverter device 40, respectively, based, in particular, on said phase angle setpoint 0A. A .

[0106] The inverter device 40 is capable of assuming an active and an inhibited configuration. In the inhibited configuration, all switching elements 42, 44, 46, 48 are in a blocked state, so the rotating transformer 22 is not energized and no electrical power is transmitted to the defrosting device 20. In the active configuration, the control device 60 is configured to control the switching elements 42, 44, 46, 48 according to a phase-shifted control. According to this control, the first and second arms 41, 45 are controlled in a phase-shifted manner, according to the phase-shift angle 0 A The phase angle 0A corresponds to the control phase shift between the switching elements of the first arm and those of the second arm.

[0107] The control of the inverter device 40, implemented by means of the control device 60, is illustrated by the three graphs in Figure 3 obtained through simulation. The top graph illustrates the evolution, as a function of time t, of the current h flowing through the main primary winding 26 of the rotating transformer, as well as the evolution, as a function of time t, of the current Î2 flowing through the secondary circuit 30 of the rotating transformer 22. The middle graph illustrates the evolution, as a function of time t, of the primary alternating voltage V p of the main primary winding 26 of the rotating transformer and the secondary alternating voltage V s of the secondary circuit 30 of the rotating transformer. The graph below shows the evolution, as a function of time t, of the voltage V pm at the terminals of the primary measuring winding 28.

[0108] The inverter device 40 is controlled, by means of the control device 60, so that it undergoes a plurality of successive control cycles. In this non-limiting example, a cycle will be considered between an initial time t0 and a final time t f It is understood that the order cycle can be considered between other chosen initial and final moments.

[0109] During a control cycle such as the one considered, the inverter device 40 is successively brought into a first controlled state between times t0 and t1, then a first short-circuit state between times t1 and t2, a second controlled state between times t2 and t3, and then a second short-circuit state between times t3 and t2. f .

[0110] In the first controlled state, the first and fourth switching elements 42, 48 are in the conducting state, while the second and third switching elements 44, 46 are in the blocking state. The current h in the main primary winding 26 and the current i2 in the secondary circuit 30 of the rotating transformer gradually increase. The primary AC voltage V p and the secondary alternating voltages are then positive, here equal. They are here approximately equal to the direct voltage V D c delivered by the continuous power supply source S, i.e. approximately 800 volts.

[0111] In the first short-circuit state, from time ti, the second and fourth switching elements 44, 48 are in the conducting state while the first and third switching elements 42, 46 are in the blocking state. The main primary winding 26 is short-circuited and the primary AC voltage V pbecomes zero immediately. Furthermore, from time ti, the current stored in the leakage inductances of the rotating transformer discharges. The currents h and i2 gradually decrease. As long as the current i2 is not zero, at least two of the diodes 53 of the diode bridge 52 remain conducting. Also, as long as the leakage inductances of the rotating transformer 22 are not completely discharged and the current i2 is not zero, the amplitude of the secondary alternating voltage V s The voltage across the secondary circuit remains positive. The DC supply voltage V a The voltage supplied to the defrosting device is then equal to said secondary alternating voltage V s At time t, the current i2 becomes zero and the secondary alternating voltage V s also becomes zero. This instant corresponds to the moment when the leakage inductances of the transformer are discharged.

[0112] At time t2, the inverter device 40 is brought into the second controlled state. The second and third switching elements 44, 46 are then in the conducting state, while the first and fourth switching elements 42, 48 are in the blocking state. The currents h and i2 decrease to negative values. The amplitude of the primary AC voltage V p and the amplitude of the secondary alternating voltage V s are then negative. They are opposite to the amplitude of the DC voltage V D c, or approximately -800 Volts.

[0113] At time t3, the inverter device 40 is brought into the second short-circuit state in which the first and third switching elements 42, 46 are in the conducting state while the second and fourth switching elements 44, 48 are in the blocking state. Here again, the main primary winding 26 is short-circuited and the primary alternating voltage V pbecomes immediately zero. The currents h and i2 gradually increase until the current i2 becomes zero at time t 33 Before that moment 33 , the amplitude of the secondary alternating voltage V s The voltage across the secondary circuit remains negative, approximately -800V. This instant t 33 corresponds to the moment when the leakage inductances of the transformer are discharged.

[0114] The rotating transformer 22 can be represented according to an equivalent diagram shown in figure 3, making the simplifying assumptions that it has a transformation ratio equal to 1, the losses of the rotating transformer are neglected and the DC power supply source S is considered ideal.

[0115] According to this equivalent representation, the equivalent rotating transformer comprises a primary leakage inductance 25, a secondary leakage inductance 31, and a magnetizing inductance 33. The voltage V pm across the terminals of the primary measuring winding 28 is then equal to the voltage across the said magnetizing inductance 33.

[0116] During a period Tl considered between times ti and tu, the primary alternating voltage V p is zero while the amplitude of the secondary alternating voltage V s The voltage across the secondary circuit is always positive and equal to the DC supply voltage V a , taking into account the discharge of the transformer's leakage inductance. Applying a voltage divider then shows that during said period Tl:

[0117] Where V pm is the voltage across the terminals of the primary winding of measurement 28, L 3iis the value of the secondary leakage inductance 31 and L25 / / 33e q is the equivalent inductance of the primary leakage inductance 25 and the magnetization inductance 33, considered in parallel with each other.

[0118] In other words, during the period Tl, the continuous supply voltage V a The power supplied to the defrosting device 20 is a function of the voltage V pm across the terminals of the primary measuring winding 28. Similarly, it can be shown that the DC supply voltage V a The power supplied to the defrosting device 20 is a function of the voltage V pm at the terminals of the primary measuring winding 28 during a period T2 defined between times t3 and t 33 .

[0119] Therefore, we can define a first measurement interval of predetermined duration, beginning at time ti when the inverter transitions from the first controlled state to the first short-circuit state, and thus within the period T1. The predetermined duration of this measurement interval is less than the duration of the period T1. This measurement interval is defined when the inverter 40 is in a short-circuit state. We can also define a second measurement interval, of predetermined duration, beginning at time t3 when the inverter 40 transitions from the second controlled state to the second short-circuit state, and thus within the period T2.

[0120] The invention then provides for measuring the value of the voltage V pm across the terminals of the primary measuring winding 28 during said measurement intervals. The measurement of the voltage V pmis synchronized with these measurement intervals. Indeed, during these intervals, the continuous supply voltage V a is a function of said voltage V pm across the terminals of the primary measuring winding 28. Also, by measuring said voltage V pm It is possible to determine the DC supply voltage V a The control device 60 is then configured to control the inverter device 40 in such a way as to limit the DC supply voltage V a delivered by the rectifier device 50 below a predetermined maximum voltage threshold, from the value of the voltage across the terminals of the primary winding of measurement measured during said measurement interval.

[0121] To achieve this, the control device 60 further includes a limiting module 70. The limiting module 70 receives said voltage measurement V pmacross the terminals of the primary measuring winding 28, as well as the state 642, 644, 646, 648 of the switching elements 42, 44, 46, 48 during said measuring intervals. Alternatively, the limiting module could be provided with the control signal for the switching elements rather than their state. When the inverter device is in the active configuration, the limiting module 70 is configured to compare the measured value of the voltage V pm across the terminals of the primary measuring winding 28, during the measurement intervals as previously defined, with a predetermined upper measuring voltage threshold V pmsu p.

[0122] Figure 5 graphically shows the inhibited configuration of the inverter device 40, allowing the continuous supply voltage V to be maintained. asupplied to the defrosting device 20 below a predetermined maximum voltage threshold, here 600 volts. The graph above shows the evolution of said DC supply voltage V a as a function of time t. The middle graph shows the evolution of the current Î2 flowing within the secondary circuit 30 of the rotating transformer 20. The bottom graph shows the evolution of an inhibition indicator Ininc, set by default to a value of unity, which controls the inhibited state of the inverter device. As can be seen in the graphs of Figure 5, before time tmax, the measured voltage V pm is lower than the predetermined upper measurement voltage threshold V pmsu p, and the DC supply voltage V ais below the maximum voltage threshold, here 600 volts. Therefore, the limiting module 70 emits no signal and the inverter device 40 remains in active mode. The Ininc inhibition indicator remains at a value of unity.

[0123] However, at time t ma x, the voltage V pm measured during the measurement interval exceeds said predetermined upper measurement voltage threshold V pmsu p, which translates to the DC supply voltage V areaching or approaching the maximum voltage threshold of 600 volts, the limiting module 70 generates an inhibition signal Inib for the control unit 64, specifically the voltage control module 66. The voltage control module 66 sets the inhibition indicator Ininc to 0. In response, the signal generation module 68 commands the blocking of all switching elements 42, 44, 46, and 48. The inverter device 40 is then brought into the inhibited configuration, so that it no longer cycles and no longer supplies voltage to the rotating transformer 22. The current Î2 becomes zero and the supply voltage remains constant. a is limited below said maximum voltage threshold and decreases progressively.

[0124] Therefore, following the inhibited configuration of the inverter device 40, the control device 60 is configured to periodically place the inverter device 40 in the active configuration during a temporary activation phase of predetermined duration. These temporary activation phases are generated by the voltage control module 66, which periodically sets the inhibition indicator Ininc to 1, based on an activation frequency F o and a calibrated phase shift angle 0 O .

[0125] As illustrated in Figure 5, this temporary activation phase of the inverter device 40 is carried out periodically, according to a period TM equal to 1 / F O Temporary activation phases are generated here at times t ai , t a2 and so on. The activation period TM of the inverter device is a multiple of the period T 40 of the primary alternating voltage V pdelivered by said inverter device 40 in active configuration. Without limitation, the predetermined duration of the temporary activation phase corresponds here to the duration of one control cycle of the inverter device 40, and therefore to the period of the primary alternating voltage V p that it delivers. During this temporary activation phase, the inverter device 40 undergoes a control cycle. Therefore, two measurement intervals, as defined previously, allow the voltage V to be measured. pm across the terminals of the primary winding of measurement 28 and consequently determine the DC supply voltage V a , are generated artificially. One advantage is that they allow the measurement of said voltage V pm as an image of the DC supply voltage V a and thus be able to regulate and limit the DC supply voltage V a , despite the inhibition of the inverter device 40.

[0126] As illustrated in the graphs of Figure 6, showing the same quantities as the graphs in Figure 5, the DC supply voltage V a decreases gradually as long as the inverter device is in the inhibited configuration. At time t u , the voltage V pm measured during a measurement interval during a temporary activation phase becomes less than a predetermined lower measurement voltage threshold V pmi nf, which translates to a value of the DC supply voltage V asufficiently far from the maximum voltage threshold to allow the inverter device to reactivate. The limiting module then delivers an inhibition interrupt signal, resulting in the inhibition signal Inib being set to 0. The voltage control module 66 sets the inhibition indicator Ininc to 1, and the control signal generation module 68 responds by activating the inverter device 40. The inverter device 40 resumes its normal operation and undergoes a series of control cycles, while the supply voltage continues to V a increases again. At time td, the voltage V pm measured during a measurement interval again exceeds said predetermined upper measurement voltage threshold V pmsu p and the inverter device is again placed in inhibited configuration according to the steps detailed previously.

Claims

Demands 1. A system (10) for de-icing the blades (14) of an aircraft propeller (12), said propeller being rotationally linked to a rotating drive element (16) of the aircraft configured to be driven by a turbomachine of the aircraft, the system comprising: a controllable H-bridge inverter device (40) having a first input terminal (40A) and a second input terminal (40B) configured to be connected to a DC power supply (S) of the aircraft, and a first output terminal (40C) and a second output terminal (40D), the inverter device being configured to deliver a primary AC voltage (V p) from a direct current voltage supplied by the direct current power supply; a rotating transformer (22) comprising: a primary primary winding (26) fixed relative to a portion of the aircraft frame (18) and connected between the first and second output terminals of the inverter device, so that it receives said primary alternating current voltage (V p ) delivered by said inverter device; a primary measuring winding (28) magnetically coupled to the main primary winding and fixed relative to said portion of the aircraft frame; a secondary circuit (30) rotationally linked to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled to the main primary winding in order to deliver a secondary alternating voltage (V s) from the primary alternating voltage received by said main primary winding; a rectifier device (50) connected to said secondary circuit of the rotating transformer and configured to deliver a direct current supply voltage (V a ) from said secondary alternating voltage, the rectifier device comprising a rectifier element (52) having two output terminals and a filter capacitor (54) connected between said output terminals of the rectifier element; a de-icing device (20) configured to de-ice the propeller blades, the de-icing device being connected to a rectifier device such that it receives said DC supply voltage; a control device (60) of the inverter device configured to control said inverter device in a phase-shifted manner, such that said inverter device describes at least one control cycle during which it takes at least one controlled state in which it delivers a positive or negative voltage and then a short-circuit state in which the voltage it delivers is zero, the control device being configured to control the inverter device using the value of the voltage (V pm ) across the terminals of the primary winding of the measured current during a measurement interval of predetermined duration, which begins at time (tn,t 33 ) where the inverter device goes from a controlled state to a short-circuit state.

2. System according to claim 1, wherein said rectifier member (52) comprises a diode bridge having two input terminals connected to said secondary circuit (30) and two output terminals connected to the defrosting device (20), the filter capacitor (54) being connected between the output terminals of the diode bridge.

3. System according to claim 1 or 2, wherein the inverter device comprises a first arm in which first and second switching elements are connected and a second arm in which third and fourth switching elements are connected, the control device (60) comprising a control unit (64) configured to control the inverter device (40) at least from a control setpoint (C*), said control unit (64) comprising a voltage control module (66) configured to generate a phase angle setpoint (0) between the switching elements (42, 44, 46, 48) of the first and second arms (41, 45) from said control setpoint (C*) of the switching elements, the control unit further comprising a control signal generation module (68) configured to generate control signals (S1, S2, S3,S4) intended for the switching elements of the inverter device (40) according to said phase angle setpoint.

4. System according to any one of claims 1 to 3, wherein the control device (60) is configured to control the inverter device (40) so as to limit the DC supply voltage delivered by the rectifier device (50) below a predetermined maximum voltage threshold.

5. A system according to claim 4, wherein the control device (60) comprises a control unit (64) configured to control the inverter device (40) at least from a control setpoint (C*) and wherein the inverter device (40) can assume at least one active configuration in which it performs said at least one control cycle and one inhibited configuration in which it does not deliver voltage, the control device (60) further comprising a limiting module (70) configured to generate an inhibition signal (Inib) for said control unit (64) when said voltage value (V pm ) across the terminals of the primary measuring winding (28), measured during said measurement interval, exceeds a predetermined upper measuring voltage threshold (V pmsup), said control unit being configured to place the inverter device in said inhibited configuration in response to the generation of said inhibition signal.

6. System according to claim 5, wherein, when said inverter device (40) is in the inhibited configuration, said control device (60) is configured to periodically place the inverter device in said active configuration during a temporary activation phase of a predetermined duration during which said inverter device describes at least one control cycle, before bringing the inverter device back into the inhibited configuration.

7. System according to claim 6, wherein the activation period (TM) whereby the inverter device (40) is periodically placed in the active configuration during a temporary activation phase is a multiple of the period of the primary AC voltage (V p) delivered by said inverter device.

8. System according to claim 6, wherein the activation period, denoted TM, according to which the inverter device (40) is periodically placed in the active configuration during a temporary activation phase satisfies the equation: TM = N x T 40 + 1 / 2X T4OOÙ T 40 is the period of the primary alternating voltage delivered by the inverter device and N is a natural integer.

9. A system according to any one of claims 6 to 8, wherein the predetermined duration of said temporary activation phase is equal to the period (T 40 ) of the primary alternating voltage (V p ) delivered by the inverter device (40) when it is in active configuration.

10. A system according to any one of claims 5 to 9, wherein the limiting module (70) is configured to generate an inhibit interrupt signal for said control unit (64) when said voltage value (V pm ) across the terminals of the primary measuring winding, measured during a temporary activation phase, over a measurement interval of predetermined duration and which begins at time (tn,t 33 ) where the inverter device transitions from a controlled state to a short-circuit state, becomes below a predetermined lower measurement voltage threshold (Vpminf), said control unit being configured to place the inverter device (40) in said active configuration in response to the generation of said inhibit interrupt signal.

11. Method for controlling a system (10) for de-icing the blades (14) of an aircraft propeller (12), said propeller being rotationally linked to a rotating drive element (16) of the aircraft configured to be driven by a turbomachine of the aircraft, the system comprising: a controllable H-bridge inverter device (40) having a first input terminal (40A) and a second input terminal (40B) configured to be connected to a DC power supply (S) of the aircraft, and a first output terminal (40C) and a second output terminal (40D), the inverter device being configured to deliver a primary AC voltage (V p ) from a direct current voltage supplied by the direct current power supply; a rotating transformer (22) comprising: a primary winding (26) fixed relative to a portion of the aircraft frame (18) and connected between the first and second output terminals of the inverter device, so that it receives said primary alternating voltage (V p ) delivered by said inverter device; a primary measuring winding (28) magnetically coupled to the main primary winding and fixed relative to said portion of the aircraft frame; a secondary circuit (30) rotationally linked to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled to the main primary winding in order to deliver a secondary alternating voltage (V s) from the primary alternating voltage received by said main primary winding; a rectifier device (50) connected to said secondary circuit of the rotating transformer and configured to deliver a direct current supply voltage (V a) from said secondary alternating voltage, the rectifier device comprising a rectifier element (52) having two output terminals and a filter capacitor (54) connected between said output terminals of the rectifier element; a de-icing device (20) configured to de-ice the propeller blades, the de-icing device being connected to the rectifier device so that it receives said DC supply voltage; the method comprising the steps in which said inverter device is controlled in a phase-shifted manner, such that said inverter device describes at least one control cycle in which it takes at least one controlled state in which it delivers a positive or negative voltage and then a short-circuit state in which the voltage it delivers is zero, and the inverter device is controlled using the value of the voltage (V pm) at the terminals of the primary winding of measurement measured during a measurement interval of a predetermined duration and which begins at the instant when the inverter device passes from a controlled state to a short-circuit state.

12. A method according to claim 11, wherein the inverter device (40) is controlled so as to limit the DC supply voltage (V a ) delivered by the rectifier device (50) below a predetermined maximum voltage threshold.

13. A method according to claim 11 or 12, wherein the inverter device (40) can assume at least one active configuration in which it undergoes at least one control cycle and an inhibited configuration in which it does not deliver a voltage, and wherein an inhibition signal (Inib) is generated when said voltage value (V pm) across the terminals of the primary measuring winding (28), measured during said measurement interval, exceeds a predetermined upper measuring voltage threshold (V pmsup ), and in which the inverter device is placed in said inhibited configuration in response to the generation of said inhibition signal.

14. A method according to claim 13, wherein, when said inverter device (40) is in the inhibited configuration, the inverter device is periodically placed in said active configuration during a temporary activation phase of a predetermined duration during which said inverter device describes at least one control cycle, and then the inverter device is brought back into the inhibited configuration.

15. Aircraft comprising a rotary drive element (16) configured to be driven in rotation by a turbomachine of the aircraft; at least one propeller having a plurality of blades (14), the propeller being rotationally linked to said rotary drive element and a system (10) for de-icing the blades (14) of the propeller (12) according to any one of claims 1 to 10.

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