Aircraft propeller blade de-icing system comprising a primary winding for measurement

Abstract

Aircraft propeller blade de-icing system comprising a primary measuring winding. Aircraft propeller blade (12) de-icing system (10) comprising an H-bridge type inverter device (40); a rotating transformer (22) comprising a main primary winding (26), a primary measuring 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 a phase-shifted manner and using the value of the voltage (Vpm) across the terminals of the primary measuring winding measured during a measurement interval of a predetermined duration and which begins at the instant (t11,t33) when the inverter device transitions from a controlled state to a short-circuit state. Figure for the abridged version: Fig. 1.

Description

Title of the invention: Aircraft propeller blade de-icing system comprising a primary winding for measuring... Technical field

[0001] 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.

[0002] Within the aircraft, the de-icing device is rotationally linked to the blades and therefore to the aircraft's propeller, and is thus positioned in the rotating frame of reference. It is therefore necessary to implement solutions to provide electrical power to the de-icing device and to control the voltage and power supplied to the de-icing device. Previous technique

[0003] Systems are known that provide electrical power to the aircraft's de-icing device, located in the rotating frame, by means of a brush-type commutator. However, these devices wear out very quickly, resulting in a limited lifespan and requiring regular maintenance.

[0004] Prior art document EP3845458B1 describes a power supply solution for a helicopter blade de-icing device. In this document, the heating mats are powered with alternating current, which is not suitable for the present application. Indeed, powering the de-icing device with alternating current imposes significant constraints in terms of 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, given the significant losses it generates. Furthermore, this type of converter is not suitable for operation in a severe thermal environment, such as that of an aircraft.

[0005] Furthermore, while the use of rotating transformers has been considered in the prior art, its implementation remains complex. Indeed, the use of a rotating transformer makes regulating the DC supply voltage provided 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 device in the rotating frame does not allow for measuring the DC supply voltage. supplied to the defrosting unit at all times. Controlling this DC supply voltage delivered to the defrosting unit is therefore particularly complex. In particular, the supplied DC supply voltage must not exceed the operating limits of the defrosting unit 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. Description of the invention

[0006] One object of the present invention is to provide a system for de-icing the propeller blades of an aircraft which remedies the aforementioned disadvantages.

[0007] 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 rotary 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 source of the aircraft, and 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 source; - 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 main primary winding and being fixed relative to said portion of the aircraft frame; a secondary circuit linked in rotation to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled with the main primary winding in order to deliver a secondary alternating voltage from the primary alternating voltage received by said main primary winding; - a rectifier device connected to said secondary circuit of the rotating transformer and configured to deliver a DC supply voltage from said AC secondary 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; - a control device for 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 across the terminals of the primary measuring winding 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.

[0008] The de-icing device is advantageously rotationally linked to said rotary drive element as well as to the aircraft propeller. The de-icing device advantageously comprises a de-icing means, for example a set of heating mats.

[0009] The rotating transformer of the system according to the invention exhibits reduced wear and maintenance requirements compared to a brushed commutator device. 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 supply the defrosting device with alternating current.

[0010] The main primary winding of the rotating transformer advantageously comprises a plurality of turns. The main primary winding and the measuring primary winding are arranged in the fixed frame. The secondary circuit of the rotating transformer is arranged in the rotating frame.

[0011] The main primary winding and the measuring primary winding define a primary circuit for the rotating transformer. They are separate. They are magnetically coupled. Without limitation, the rotating transformer may comprise a plurality of main primary windings. Only the main primary winding, or main primary windings, 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 intended to enable voltage measurement and does not contribute to energy transfer.

[0012] The primary measuring winding is advantageously arranged in parallel with the main primary winding, on the same magnetic circuit in the stationary part. 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.

[0013] 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 secondary winding and the second secondary winding are connected together at a central node, said central node being connected to a ground line.

[0014] The rectifier device imposes the DC supply voltage on the defrosting device. Without limitation, the rectifier may comprise a diode bridge or a synchronous rectifier comprising a plurality of MOSFET transistors. The output terminals of the rectifier are advantageously connected to the defrosting device. The filter capacitor is configured to impose the DC supply voltage on the defrosting device. The filter capacitor presents the 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 advantageously correspond to the output terminals of the rectifier device.

[0015] The inverter device is configured to deliver said primary alternating voltage from the direct voltage supplied by the direct power supply. Advantageously, the inverter device is fixed relative to the aircraft frame portion and is therefore located in the fixed frame.

[0016] 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.

[0017] The control device is advantageously configured to regulate the power supplied to the defrosting device. The control device allows the inverter device to be controlled in order to power the transformer.

[0018] The control device is configured to control the H-bridge inverter device according to a phase-shifted 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. Such control differs from symmetrical control. The use, according to the invention, of an inverter device controlled by a phase-shifted control method reduces losses within the system and therefore its heating. The system according to the invention is therefore particularly suitable for integration within an aircraft where the thermal environment is harsh.

[0019] 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.

[0020] The set of positive or negative voltages delivered during the phases where the inverter device is in the controlled state and the zero voltages delivered during the phases where the inverter device is in the short-circuit state constitutes the primary alternating voltage delivered by the inverter device.

[0021] It is understood that the said instant at which the measurement interval begins corresponds to the instant when the inverter device passes from one or the other of these controlled states to one or the other of these short-circuit states.

[0022] More specifically, when the inverter device transitions from a controlled state to a short-circuit state, the main primary winding of the transformer is short-circuited, and the voltage delivered by the inverter device becomes virtually zero 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 become zero immediately but only after a certain time. This delay is due to the current stored in the leakage inductances of the rotating transformer, which discharge gradually.

[0023] This results in a period during which the voltage delivered by the inverter device 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 imposed by the filter capacitor of the rectifier device.

[0024] The measurement interval is selected within this period, such that the measurement of the voltage across the primary winding is performed after the inverter device transitions from a controlled state to a short-circuit state, but before the secondary AC voltage drops to zero. Without limitation, said measurement of the voltage across the primary winding may be performed at the instant the inverter device transitions from a controlled state to a short-circuit state, or after that instant, within the measurement interval.

[0025] 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.

[0026] The predetermined duration of the measurement interval is advantageously chosen according to the nature of the rotating transformer. Preferably, the predetermined duration of the measurement interval is chosen to be less than a known time after which the leakage inductances of the rotating transformer are completely discharged.

[0027] Preferably, the voltage across the primary measuring winding is measured while the inverter device is in a short-circuit state. In other words, the measurement interval is chosen to correspond to a period during which the inverter device is in a short-circuit state. Preferably, the voltage across the primary measuring winding is measured before the inverter device enters a new controlled state.

[0028] 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.

[0029] 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 makes it possible to control the inverter device and advantageously to control the voltage and power supplied to the defrosting device, 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.

[0030] 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.

[0031] By way of non-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.

[0032] 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 terminals of the primary measuring winding measured during said measuring interval.

[0033] By way of exception, the voltage across the primary measuring winding can be measured at any time during the measurement interval. Preferably, the system includes a measuring element configured to measure the voltage across the primary measuring winding.

[0034] 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.

[0035] Preferably, but not limitingly, 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.

[0036] 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.

[0037] The measurement of the value of the voltage across the terminals of the primary measuring winding is advantageously synchronized with said measuring interval.

[0038] 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 it from being affected by the switching of the switching elements.

[0039] 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.

[0040] In the blocked state, the switching elements of the inverter device behave like open switches, thus preventing current flow. In the conducting state, the switching elements behave like closed switches and carry a non-zero current. Preferably, but not exclusively, the switching elements of the inverter device comprise a transistor, for example, a MOSFET transistor.

[0041] The control device allows the switching elements of the inverter device to be controlled. The control device also allows the transformer to be powered.

[0042] According to the 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.

[0043] 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 blocked 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 blocked state, in which case the voltage delivered by the inverter device is negative, preferably of constant amplitude.

[0044] In said 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.

[0045] Preferably, but not limitingly, 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.

[0046] 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.

[0047] 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.

[0048] When the inverter device is in a controlled state, the rotating transformer supplies current to the rectifier device and its diodes are conducting. Following a transition to a short-circuit state of the inverter device, the leakage inductances of the rotating transformer gradually discharge and the diodes of the rectifier device remain conducting until the current delivered by the rotating transformer drops to zero, at which point the diodes become reverse-biased and the secondary AC voltage is zero.

[0049] 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.

[0050] 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.

[0051] Said 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 said control setpoint by means of a regulation loop voltage, using the value of the voltage across the terminals of the primary 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.

[0052] The control device advantageously includes a power control module configured to generate said 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 said 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.

[0053] Preferably, the control device is configured to control the inverter device so as to limit the DC supply voltage delivered by the rectifier device below a predetermined maximum voltage threshold.

[0054] It is understood that the control device is configured to limit the DC supply voltage by using said measurement of the voltage across the terminals of the primary measuring winding. This voltage limitation is therefore facilitated and more precise, which reduces the risk of damage to the defrosting device.

[0055] 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 said defrosting device. This measuring threshold is advantageously chosen so as to maintain the DC supply voltage provided to the defrosting device below the predetermined maximum voltage threshold.

[0056] Advantageously, the control device comprises a control unit configured to control the inverter device at least from a control setpoint, and the inverter device 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 a voltage, the control device further comprising 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 unit of command being configured to place the inverter device in said inhibited configuration in response to the generation of said inhibition signal.

[0057] 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, said inverter device undergoes a plurality of successive control cycles. The configuration corresponds to normal operation of the inverter device, enabling the generation of the primary alternating voltage.

[0058] In the inhibited configuration, the inverter device is stopped, so that 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 device in the inhibited configuration, the DC supply voltage delivered by the rectifier device is kept below the predetermined upper measuring voltage threshold and tends to decrease over time. As long as the inverter device 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 thereby better protected.

[0059] Preferably, in the inhibited configuration, all the switching elements of the inverter device are placed in the blocked state.

[0060] 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.

[0061] When in the inhibited configuration, the inverter device no longer undergoes any control cycles and therefore no longer transitions from a controlled state to a short-circuit state. While the inverter device is in the inhibited configuration, it is no longer possible to measure the value of said voltage across the primary measuring winding during a measurement interval of predetermined duration, which begins the instant the inverter device transitions from a controlled state to a short-circuit state. In this configuration, it is therefore no longer possible to determine the DC supply voltage delivered by the rectifier device from a measurement of said voltage across the primary measuring winding.

[0062] Periodically activating the inverter device during a temporary activation period artificially generates a control cycle during which the inverter device 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 measuring winding. This allows the voltage across the primary measuring winding to be measured, and based on this measurement, operation to resume in the active configuration as soon as the voltage across the defrosting device returns to a normal and / or acceptable level.

[0063] According to an advantageous embodiment, 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 alternating voltage delivered by said inverter device.

[0064] According to another advantageous variant, the activation period, denoted TM, according to which the inverter device is placed periodically in the active configuration during a temporary activation phase satisfies the equation: TM-Nx ^40 + V2 x T40 where T40 is the period of the primary alternating voltage delivered by the inverter device and N is a natural number.

[0065] Such an activation period allows the direction of the voltage pulses across the rotating transformer to be reversed in order to avoid a slightly unbalanced loading of the transformer's magnetizing inductance. This variant therefore compensates for any potential imbalance in the magnetizing current.

[0066] Preferably, the predetermined duration of said temporary activation phase is equal to the period of the primary AC voltage delivered by the inverter device when it is in the active configuration. During said temporary activation period, said 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 assumes 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 to ensure the generation of at least one measurement interval in order to guarantee a reliable and robust measurement of the voltage across the primary measuring winding.

[0067] Preferably, said predetermined duration is less than a maximum duration threshold. The maximum duration threshold is chosen so that said predetermined duration is sufficiently short so as not to supply too much energy to the rectifier device, and in particular to its filter capacitor, during temporary activation. This duration predetermined is chosen long enough to guarantee a measurement interval sufficient to allow a reliable measurement of the voltage across the terminals of the primary measuring winding.

[0068] Preferably, the limiting module is configured to generate an inhibition interrupt signal for said control unit when said value of the voltage across the terminals of the primary measuring winding, measured during a temporary activation phase, during a measurement interval of predetermined duration and which begins at the instant (tn,t33) when the inverter device changes from a controlled state to a short-circuit state, becomes less than a lower predetermined measuring voltage threshold, said control unit being configured to place the inverter device in said active configuration in response to the generation of said inhibition interrupt signal.

[0069] 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 is brought back to its active configuration, resuming normal operation in which it performs one or more control cycles.

[0070] Advantageously, the energy returned during such an activation phase is sufficiently low so as not to prevent the voltage from decreasing between two activation phases.

[0071] Preferably, said lower threshold of predetermined measurement voltage is determined so as to correspond to a value of the DC supply voltage sufficiently far from the predetermined maximum voltage threshold to allow a new activation of the inverter device, without risk of damaging the system.

[0072] 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 rotary 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 source of the aircraft, and 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 source; - 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 main primary winding and being fixed relative to said portion of the aircraft frame; a secondary circuit linked in rotation to the rotating drive element of the aircraft, the secondary circuit being magnetically coupled with the main primary winding in order to deliver a secondary alternating voltage from the primary alternating voltage received by said main primary winding; - a rectifier device connected to said secondary circuit of the rotating transformer and configured to deliver a DC supply voltage from said AC secondary 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 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 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.

[0073] Advantageously, the inverter device is controlled so as to limit the DC supply voltage delivered by the rectifier device below a predetermined maximum voltage threshold.

[0074] 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 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, according to a setpoint of phase shift angle between the switching elements of the first and second arms.

[0075] 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 terminals of 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.

[0076] 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 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.

[0077] 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.

[0078] The invention further 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. Brief description of the drawings

[0079] 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:

[0080] [Fig.1] [Fig.1] shows a system, according to the invention, for de-icing the propeller blades of an aircraft;

[0081] [Fig.2] [Fig.2] shows the control device of the system of [Fig.1];

[0082] [Fig.3] [Fig.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 the [Fig.l];

[0083] [Fig.4] [Fig.4] shows an equivalent representation of the rotating transformer of the system of [Fig.1];

[0084] [Fig. 5] [Fig. 5] shows a graphical representation of a limitation procedure of the DC supply voltage provided to the defrosting device by means of the system in [Fig. 1]; and

[0085] [Fig.6] [Fig.6] is a graphical representation of the evolution of the quantities of the [Fig.5], during the active configuration of the inverter device. Description of the implementation methods

[0086] The invention relates to a system for de-icing the propeller blades of an aircraft.

[0087] Figure 1 shows the system 10 for de-icing the blades 14 of the propeller 12 of a aircraft, according to the invention. In [Fig. 1], only one blade is shown. The aircraft comprises 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 propeller 12 of the aircraft pivots. The aircraft also comprises a portion of the aircraft frame 18, defining a fixed frame. The aircraft further comprises a DC power supply S configured to deliver a DC voltage V. The power supply S may be a DC bus of the aircraft.

[0088] 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 the formation of ice on said blade. The de-icing device 20 is rotationally linked to the rotating drive element 16 and is disposed in the rotating reference frame.

[0089] The system 10 further comprises a rotating transformer 22. The rotating transformer 22 comprises a primary circuit 24 including 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 arranged in the fixed frame. The rotating transformer 22 further comprises 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 secondary winding and the second secondary winding 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 arranged in the rotating frame.

[0090] The system includes a measuring element 36 configured to measure the voltage Vpm across the terminals of the primary measuring winding 28.

[0091] The system 10 further includes an inverter device 40 fixed relative to the aircraft frame portion 18 and disposed in the fixed reference frame. 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.

[0092] 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 and in which a first controllable switching element 42 and a second controllable switching element 44 are connected. The first and second switching elements 42, 44 are separated by a first midpoint Pi connected to said first output terminal 40C. The first switching element 42 is connected between the first input terminal 40A and the first output terminal 40C. The second switching element 44 is connected between the second input terminal 40B and the first output terminal 40C.

[0093] The inverter device 40 further comprises a second arm 45 parallel to the first arm 41, in which a third controllable switching element 46 and a fourth controllable switching element 48 are connected. The second and third switching elements 46, 48 are separated by a second midpoint P2 connected to said second output terminal 40D. The third switching element 46 is connected between the first input terminal 40A and the second output terminal 40D. The fourth switching element 48 is connected between the second input terminal 40B and the second output terminal 40D.

[0094] 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 blocked state.

[0095] The inverter device 40 is configured to deliver a primary alternating voltage Vp to the main primary winding 26, from said direct voltage VDC supplied by the direct power supply S. The main primary winding 26 therefore presents the primary alternating voltage Vp at its terminals.

[0096] 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 Vs from of the primary alternating voltage Vp 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.

[0097] The system 10 further comprises a rectifier device 50 rotationally linked to the rotating drive element 16 and disposed in the rotating frame. The rectifier device 50 comprises 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 blocked or forward-biased depending on the direction of the current. The rectifier device 50 further comprises a filter capacitor 54 connected between the output terminals of the diode bridge 52. The rectifier device 50 further comprises a resistor 56 connected in parallel with the filter capacitor 54.

[0098] 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 AC voltage V s delivered by the rotating transformer 22.

[0099] 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 provided by the rectifier device 50 to the defrosting device 20.

[0100] The control device 60 is schematically illustrated in [Fig. 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 measurement of the power Pm supplied to the defrosting device 20. The power control module 62 enables power regulation of the system and, in particular, regulation of the power supplied to the defrosting device 20.

[0101] 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 of 0 A, 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 respectively for the first, second, third, and fourth switching elements 42, 44, 46, 48 of the inverter device 40, based in particular on said phase angle setpoint of 0 A.

[0102] The inverter device 40 is capable of assuming an active configuration and an inhibited configuration. In the inhibited configuration, all switching elements 42, 44, 46, 48 are in the blocked state so that the rotating transformer 22 is not energized and no electrical energy is transmitted to the defrosting device 20.

[0103] In the active configuration, the control device 60 is configured to control the switching elements 42, 44, 46, 48 according to a so-called phase-shifted, offset, or "phase shift" control. According to this control, the first and second arms 41, 45 are controlled in a phase-shifted manner, according to the said phase shift angle 0 A. The phase shift angle 0 A corresponds to the control phase shift between the switching elements of the first arm and those of the second arm.

[0104] The control of the inverter device 40, implemented by means of the control device 60, is illustrated by the three graphs in [Fig. 3] obtained by simulation. The top graph illustrates the evolution, as a function of time t, of the current ii 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 i2 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 AC voltage Vp of the main primary winding 26 of the rotating transformer and of the secondary AC voltage Vs of the secondary circuit 30 of the rotating transformer. The bottom graph shows the evolution, as a function of time t, of the voltage Vpm across the terminals of the measuring primary winding 28.

[0105] The inverter device 40 is controlled, by means of the control device 60, so that it describes 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 t11. It is understood that the control cycle can be considered between other chosen initial and final times.

[0106] During a control cycle such as the one considered, the inverter device 40 is successively brought into a first controlled state between times 10 and 11, then a first short-circuit state between times 11 and 12, a second controlled state between times 12 and 13, and then a second short-circuit state between times 13 and t f-

[0107] 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 ii 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 Vp and the secondary AC voltage are then positive, here equal. They are here substantially equal to the DC voltage V DC delivered by the DC power supply source S, i.e. approximately 800 volts.

[0108] In the first short-circuit state, from time 11 onwards, 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 Vp immediately becomes zero. Furthermore, from time 11 onwards, the current stored in the leakage inductances of the rotating transformer discharges. The currents i1 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 AC voltage Vs across the secondary circuit remains positive.The DC supply voltage Va provided to the defrosting device is then equal to the aforementioned secondary AC voltage Vs. At time tn, the current i2 becomes zero and the secondary AC voltage Vs also becomes zero. This instant tu corresponds to the moment when the leakage inductances of the transformer are discharged.

[0109] 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 ii and i2 decrease to negative values. The amplitude of the primary AC voltage Vp and the amplitude of the secondary AC voltage Vs are then negative. They are opposite to the amplitude of the DC voltage VDC, i.e., approximately -800 Volts.

[0110] 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. Again, the main primary winding 26 is short-circuited and the primary AC voltage Vp immediately becomes zero. The currents i1 and i2 gradually increase until the current i2 becomes zero at time 133. Before this time 133, the amplitude of the secondary AC voltage Vs across the secondary circuit remains negative, approximately equal to -800V. This time 133 corresponds to the moment when the leakage inductances of the transformer are discharged.

[0111] The rotating transformer 22 can be represented according to an equivalent diagram shown in [Fig. 3], making the simplifying assumption that it has a turns ratio of 1, the losses of the rotating transformer are neglected and the continuous power supply source S is considered ideal.

[0112] 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 Vpm across the primary measuring winding 28 is then equal to the voltage across said magnetizing inductance 33.

[0113] During a period T1 considered between times t1 and tn, the primary alternating voltage Vp is zero while the amplitude of the secondary alternating voltage Vs across the secondary circuit is always positive and equal to the DC supply voltage Va, taking into account the discharge of the transformer's leakage inductance. Applying a voltage divider then shows that during said period T1 l=vs=Mi+4^)

[0114] Where V pm is the voltage across the primary measuring winding 28, L 3i is the value of the secondary leakage inductance 31 and L 25 / / 33eq is the equivalent inductance of the primary leakage inductance 25 and the magnetizing inductance 33, considered in parallel with each other.

[0115] In other words, during the period T1, the DC supply voltage V a supplied to the defrosting device 20 is a function of the voltage V pm across the primary measuring winding 28. Similarly, it can be shown that the DC supply voltage V a supplied to the defrosting device 20 is a function of the voltage V pm across the primary measuring winding 28 during a period T2 defined between times 13 and t 33.

[0116] Therefore, a first measurement interval of predetermined duration can be defined, beginning at time t11 when the inverter device 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 device 40 is in a short-circuit state. A second measurement interval of predetermined duration can also be defined, beginning at time t3 when the inverter device 40 transitions from the second controlled state to the second short-circuit state, and thus within the period T2.

[0117] The invention then provides for measuring the value of the voltage Vpm across the terminals of the primary measuring winding 28 during said measurement intervals. The measurement of the voltage Vpm is synchronized with said measurement intervals. Indeed, during these intervals, the DC supply voltage Va is a function of said voltage Vpm across the terminals of the primary measuring winding 28. Also, by measuring From the said voltage Vpm, it is possible to determine the DC supply voltage Va. The control device 60 is then configured to control the inverter device 40 so as to limit the DC supply voltage Va 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.

[0118] To this end, the control device 60 further includes a limiting module 70. The limiting module 70 receives the measured voltage Vpm across the primary measuring winding 28, as well as the state e42, e44, e46, e48 of the switching elements 42, 44, 46, 48 during the measurement intervals. Alternatively, the limiting module could be supplied with the command to 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 Vpm across the primary measuring winding 28, during the measurement intervals as previously defined, with a predetermined upper threshold of the measuring voltage Vpmsup.

[0119] Figure 5 graphically shows the inhibited configuration of the inverter device 40, which maintains the DC supply voltage Va provided to the defrosting device 20 below a predetermined maximum voltage threshold, here 600 volts. The top graph shows the evolution of said DC supply voltage Va as a function of time t. The middle graph shows the evolution of the current i2 flowing within the secondary circuit 30 of the rotating transformer 20. The bottom graph shows the evolution of an inhibition indicator Ininc, which is set to a value of one by default, and which controls the inhibited state of the inverter device.

[0120] As can be seen in the graphs of [Fig. 5], before time t max, the measured voltage Vpm is lower than the predetermined upper measurement voltage threshold Vpmsup, and the DC supply voltage Va is lower than the maximum voltage threshold, here 600 volts. Therefore, the limiting module 70 does not emit any signal, and the inverter device 40 remains in the active configuration. The inhibition indicator Ininc is maintained at a unity value.

[0121] Conversely, at time t max, the voltage Vpm measured during the measurement interval exceeds the predetermined upper measurement voltage threshold VpmSup, resulting in the DC supply voltage Va reaching or approaching the maximum voltage threshold of 600 volts. The limiting module 70 then generates an inhibition signal Inib for the control unit 64, and more specifically for the voltage control module 66. The voltage control module 66 passes The inhibition indicator Ininc is set to 0. In response, the signal generation module 68 commands the blocking of all switching elements 42, 44, 46, 48. The inverter device 40 is then brought into the inhibited configuration, so that it no longer describes a control cycle and no longer delivers voltage to the rotating transformer 22. The current i2 becomes zero and the DC supply voltage Va is limited below the said maximum voltage threshold and gradually decreases.

[0122] Therefore, following the inhibited configuration of the inverter device 40, the control device 60 is configured to periodically place the inverter device 40 in said 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 and a calibrated phase angle 0 0.

[0123] As illustrated in [Fig. 5], this temporary activation phase of the inverter device 40 is performed periodically, with a period TM equal to 1 / F₀. Temporary activation phases are generated at times t₁ᵢ, t₁ᵢ₂, and subsequent times. The activation period TM of the inverter device is a multiple of the period T₄₀ of the primary AC voltage Vₚ delivered by said inverter device 40 in its 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 AC voltage Vₚ that it delivers. During this temporary activation phase, said inverter device 40 completes one control cycle.Therefore, two measurement intervals, as defined previously, are artificially generated, allowing the voltage Vpm across the primary measuring winding 28 to be measured and the DC supply voltage Va to be determined accordingly. One advantage is that this allows the voltage Vpm to be measured as a representation of the DC supply voltage Va, thus enabling the regulation and limiting of the DC supply voltage Va, even when the inverter device 40 is disabled.

[0124] As illustrated in the graphs of [Fig. 6], showing the same quantities as the graphs of [Fig. 5], the DC supply voltage Va gradually decreases while the inverter device is in the inhibited configuration. At time tu, the voltage Vpm measured during a measurement interval during a temporary activation phase falls below a predetermined lower measurement voltage threshold Vpminf, indicating a value of the DC supply voltage Va sufficiently far from the maximum voltage threshold to allow the inverter device to be reactivated. The limiting module then delivers a The inhibition interruption signal, here manifested by setting the inhibition signal Inib to 0, is triggered. The voltage control module 66 sets the inhibition indicator Ininc to 1, and the control signal generation module 68 responds by switching the inverter device 40 to its active configuration. The inverter device 40 resumes normal operation and undergoes a series of control cycles, while the DC supply voltage Va increases again. At time td, the voltage Vpm measured during a measurement interval again exceeds the predetermined upper measurement voltage threshold Vpmsup, and the inverter device is once again placed in its inhibited configuration according to the steps detailed previously.

Claims

1. Demands System (10) for de-icing the blades (14) of the propeller (12) of an aircraft, 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 type 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, as well as a first output terminal (40C) and a second output terminal (40D), the inverter device being configured to deliver a primary AC voltage (Vp) from a DC voltage delivered by the DC power supply; - a rotating transformer (22) comprising: a primary main 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 (Vp) delivered by said inverter device; a primary measuring winding (28) magnetically coupled to the main primary winding and being fixed with respect 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 (Vs) 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 DC supply voltage (Va) 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; - 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 (Vpm) across the primary measuring winding measured during a measurement interval of predetermined duration and which begins at the instant (tn,t33) when the inverter device passes 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. A 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 (0A) 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. 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 describes said at least one control cycle and an 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) to said control unit (64) when said value of the voltage (Vpm) across the primary measuring winding (28), measured during said measuring interval, exceeds a predetermined upper measuring voltage threshold (Vpmsup),said control unit being configured to place the inverter device in said inhibited configuration in response to the generation of said inhibit 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 (Vp) 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 xT40+ ' / 2 x ^o where T40 is the period of the primary alternating voltage delivered by the inverter device and N is a natural number.

9.

10.

11. System according to any one of claims 6 to 8, wherein the predetermined duration of said temporary activation phase is equal to the period (T40) of the primary alternating voltage (Vp) delivered by the inverter device (40) when it is in active configuration. System according to any one of claims 5 to 9, wherein the limiting module (70) is configured to generate an inhibition interrupt signal for said control unit (64) when said value of the voltage (Vpm) across the primary measuring winding, measured during a temporary activation phase, during a measurement interval of predetermined duration and which begins at the instant (tn,t33) when the inverter device changes from a controlled state to a short-circuit state, becomes less than a predetermined lower threshold of measuring voltage (Vpminf), said control unit being configured to place the inverter device (40) in said active configuration in response to the generation of said inhibition interrupt signal. Method of controlling a system (10) for de-icing the blades (14) of the propeller (12) of an aircraft, 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 inverter device (40) of the H-bridge type 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, as well as a first output terminal (40C) and a second output terminal (40D), the inverter device being configured to deliver a primary AC voltage (Vp) from a DC voltage delivered by the DC power supply; - a rotating transformer (22) comprising: a primary main 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 (Vp) 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 (Vs) 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 DC supply voltage (Va) 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 (Vpm) 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.;

12. A method according to claim 11, wherein the inverter device (40) is controlled so as to limit the DC supply voltage (Va) 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 said at least one control cycle and an inhibited configuration in which it does not deliver voltage, and wherein an inhibition signal (Inib) is generated when said

14.

15. voltage value (Vpm) across the primary measuring winding (28), measured during said measurement interval, exceeds a predetermined upper measuring voltage threshold (Vpmsup), and in which the inverter device is placed in said inhibited configuration in response to the generation of said inhibition signal. 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. 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.