Synchronous electric machine for aircraft, associated propulsion device, turboshaft engine and method

Abstract

The invention relates to a synchronous electric machine (10) for an aircraft, comprising a stator (13) comprising two sets of stator coils (47, 49) intended to be connected to different power converters and a wound rotor (38) inserted in the stator, and comprising a rotor shaft (11) and two rotor coils (39, 40), each rotor coil is intended to be supplied by a different supply current. The two sets of stator coils are arranged in the stator such that when a first set of stator coils (47) fails, a second set of stator coils (49) cooperates with at least a second rotor coil (40) powered by an associated supply current to generate a mechanical torque on the rotor shaft, and such that the power converter connected to the first set of stator coils does not deliver any electrical power.

Description

Technical Field

[0001] The present invention relates to a rotating electric machine for an aircraft, and more particularly to a synchronous electric machine with a wound rotor for an aircraft.

[0002] The invention also relates to a propulsion device and a propulsion system comprising such an electric machine, an aircraft comprising such a propulsion device or such a propulsion system and a method for controlling such an electric machine. Background Art

[0003] A VTOL type aircraft, for example a twin-engine helicopter, comprises a propulsion system comprising two turboshaft engines, each turboshaft engine comprising a gas generator and a free turbine rotated by the gas generator and integral with an output shaft. The output shaft of each free turbine is suitable for driving a power transmission box, which in turn drives the helicopter rotor blades. It is known that when the helicopter is in a cruising flight situation (i.e. when the helicopter is operating under normal conditions during all phases of flight (excluding instant take-off, climbing, landing or hovering phases)), the turboshaft engines produce low power less than the maximum continuous power. These low power levels make the specific consumption (hereinafter referred to as Cs, which is defined as the ratio between the hourly fuel consumption of the combustion chamber of the turboshaft engine and the mechanical power supplied by the turboshaft engine) greater than Cs of the maximum take-off power by 30%, thus resulting in excessive fuel consumption in cruising flight.

[0004] In order to reduce the fuel consumption of a helicopter, it is known to put one of the two turbines in standby mode in cruising flight conditions, allowing the other engine to run at high speed and thus benefit from a much lower specific consumption.

[0005] In order to overcome critical situations, in particular in the event of a failure of a gas turbine that is not in standby mode, or in the event of an evasive maneuver, it is necessary to quickly restart the turbine that is in standby mode.

[0006] Since this is a critical procedure, it is necessary to ensure a high degree of reliability of the restart procedure of the turbine in standby mode to ensure the flight safety of the helicopter.

[0007] Document FR3027058 discloses a helicopter comprising at least one turboshaft engine as described above and a hybrid turboshaft engine comprising a turboshaft engine as described above and a rapid restart system comprising two restart chains.

[0008] Each restart chain comprises a rotating electrical machine and a power conversion device for operating the electrical machine.

[0009] The helicopter also includes electrical energy storage and an onboard network to power the power conversion device.

[0010] Each electric motor enables the hybrid turboshaft engine to react quickly when it is in standby mode.

[0011] The redundancy of the restart chain ensures a high degree of reliability for the "fast restart" function.

[0012] However, the redundancy of the restart chain increases the mass of the helicopter, thereby reducing the helicopter's payload, and increases the bulk of the rapid restart system.

[0013] Furthermore, it is known to replace at least one turbine intended to generate thrust for conventional take-off and landing (CTOL) type aircraft by an electric motor driving a propeller or rotor blades in order to reduce the high fossil fuel consumption of the aircraft, in particular kerosene.

[0014] Typically, an electric motor comprises a rotor equipped with permanent magnets.

[0015] However, when the rotor is rotated by a propeller or rotor blades driven by an incident air flow ("windmilling"), the magnets generate an excitation flux in the motor which induces a short-circuit current in the static winding of the motor.

[0016] This short-circuit current heats the motor and may damage it.

[0017] Furthermore, when a stator winding fails, the excitation flux generated by the permanent magnets induces a current in the failed stator winding, which may propagate the fault. Summary of the invention

[0018] The present invention aims to overcome all or some of these disadvantages.

[0019] In view of the above, the object of the present invention is a synchronous electric machine for an aircraft, comprising a stator and a wound rotor inserted into the stator, the stator comprising two sets of stator coils intended to be connected to different power converters, the wound rotor comprising a rotor shaft and two rotor coils, each rotor coil intended to be powered by a different supply current.

[0020] The two sets of stator coils are arranged in the stator so that when a first set of stator coils fails, the second set of stator coils cooperates with at least a second rotor coil powered by an associated supply current to generate electrical energy at terminals of the second set of stator coils or mechanical torque on the rotor shaft, and so that a power converter connected to the first set of stator coils does not deliver any electrical power.

[0021] The failed first set of stator coils is no longer supplied with electrical power in order to prevent the propagation of a fault due to induction of a short circuit current in the failed set of stator coils of a converter in the machine and in a power converter connected to the failed set of coils.

[0022] Despite a failure of the first set of coils, the second set of coils ensures the operation of the machine, so that the machine delivers a mechanical torque to its rotor shaft equal to the rated working torque of the motor, or delivers an electrical power to its terminals equal to the rated electrical power delivered by the motor, thereby increasing the operating reliability of the motor.

[0023] Preferably, two rotor coils are arranged in series on the rotor shaft, and the first group of stator coils and the second group of stator coils are arranged in the stator, so that the first rotor coil and the first group of stator coils form a first electromagnetic converter, and the second rotor coil and the second group of stator coils form a second electromagnetic converter.

[0024] Advantageously, the rotor comprises two identical magnetic rotor half-mass blocks extending in the longitudinal direction of the rotor, and the stator comprises two identical magnetic stator half-mass blocks extending in the longitudinal direction of the stator, each rotor coil being inserted into a different magnetic rotor half-mass block, and each group of stator coils being inserted into a different magnetic stator half-mass block.

[0025] Preferably, the rotor comprises two sets of supply rings, each set of supply rings being connected to a different rotor coil, and wherein the stator comprises two sets of brushes, each set of brushes supplying a different set of rings, each set of brushes being intended to be connected to one of the second power converters.

[0026] A propulsion device for an aircraft is also proposed, comprising an electric machine as defined above and a propulsion propeller connected to a rotor shaft.

[0027] A hybrid turboshaft engine for an aircraft is also proposed, comprising an electric machine as defined above and a turboshaft engine comprising a gas free turbine also connected to the rotor shaft of the electric machine.

[0028] An aircraft is also proposed, comprising a propulsion device as defined above or a hybrid turboshaft engine as defined above.

[0029] A method for controlling a synchronous electric machine for an aircraft is also proposed, the electric machine comprising a stator and a wound rotor inserted into the stator, the stator comprising two sets of stator coils connected to different power converters, the wound rotor comprising a rotor shaft and two rotor coils, each rotor coil being powered by a different supply current.

[0030] The method includes deactivating a failed first set of stator coils by operating a power converter connected to the first set so that the converter does not deliver any electrical power to the set of stator coils, powering a second set of stator coils by an associated power converter, and providing at least one power supply to the second coils by an associated supply current so as to generate mechanical torque on the rotor shaft or generate electrical energy at terminals of the second set of stator coils.

[0031] Preferably, the rotor comprises two identical magnetic rotor half-mass blocks extending in the longitudinal direction of the rotor, and the stator comprises two identical magnetic stator half-mass blocks extending in the longitudinal direction of the stator, each rotor coil is inserted into a different magnetic rotor half-mass block, and each group of stator coils is inserted into a different magnetic stator half-mass block, and the method comprises controlling the supply current so that the amplitude of the current supplying the rotor coils of the rotor half-mass block covering the first group of stator coils is reduced, so that when the rotor half-mass block covers all of the first group of stator coils, the control current is substantially zero, and so that when the rotor half-mass block does not cover the first group of stator coils, the amplitude of the control current increases, and the effective value of the control current is non-zero.

[0032] Advantageously, each supply current is sinusoidal. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other objects, characteristics and advantages of the present invention will become apparent on reading the following description given only as a non-limiting example and made with reference to the accompanying drawings, in which:

[0034] [ Figure 1 ] schematically shows a first example of an aircraft according to the invention;

[0035] [ Figure 2 ] shows an electrical diagram of a first example of an electric machine according to the invention;

[0036] [ Figure 3 ] schematically shows a cross section of a first example of an electric machine according to the invention;

[0037] [ Figure 4 ] shows an electrical diagram of a second example of an electric machine according to the invention;

[0038] [ Figure 5 ] schematically shows a radial section through a second example of an electric machine according to the invention,

[0039] [ Figure 6 ] shows a schematic model of a second example of an electric machine according to the present invention;

[0040] [ Figure 7 ] schematically shows the variation of the rotor current of the second example of the motor according to the present invention, and

[0041] [ Figure 8 ] schematically shows a first example of an aircraft according to the invention. DETAILED DESCRIPTION

[0042] refer to Figure 1 , which schematically shows an example of an aircraft 1 of the twin-engine VTOL type, comprising rotor blades 2 , a gearbox 3 , a turboshaft engine 4 and a hybrid turboshaft engine 5 .

[0043] The turboshaft engine 4 and the hybrid turboshaft engine 5 drive the rotor blades 2 via the gearbox 3 .

[0044] The turboshaft engine 4 comprises a gas generator 6 which generates hot gases by combustion of a fuel, such as kerosene, and a free turbine 7 which is connected to a first input of the gearbox 3 .

[0045] The hot gases generated by the gas generator 6 drive the free turbine 7 which in turn generates a mechanical torque that drives the rotor blades 2 .

[0046] The hybrid turboshaft engine 5 comprises a gas generator 8, a free turbine 9, an electric machine 10 and a control device 12 of the machine 10, wherein the gas generator generates hot gases by combustion of a fuel (such as kerosene), the free turbine 9 is connected to a first input end of the gearbox 3, and the electric machine comprises a rotor shaft 11 connected to the free turbine 9.

[0047] The hot gases generated by the gas generator 8 drive the free turbine 9 which in turn generates a mechanical torque that drives the rotor blades 2 .

[0048] The machine 10 may be operated in motor mode to deliver a driving mechanical torque to drive the free turbine 9 or in generator mode so that the free turbine 9 drives the rotor shaft 11 and the machine 10 generates electrical energy.

[0049] When the helicopter is in cruising flight conditions, the gas generator 8 of the hybrid turboshaft engine 5 is stopped in order to save fuel.

[0050] When it is necessary to restart the hybrid turboshaft engine 5 , for example during an avoidance maneuver to avoid an obstacle in flight, or when a failure of the turbine 4 occurs, the machine 10 drives the free turbine 9 in order to facilitate the starting of the hybrid turboshaft engine 5 .

[0051] The machine 10 is of the multi-phase synchronous type having a wound rotor.

[0052] It is assumed hereinafter that the machine 10 is three-phase.

[0053] Figure 2 An electrical diagram of a first example of a machine 10 and a control device 12 is shown.

[0054] The machine 10 comprises a stator 13 including a first set of stator coils and a second set of stator coils (not shown in this figure).

[0055] The coils in the first group form a first group of three phases, for example star-coupled or delta-coupled, each phase comprising the same number of poles.

[0056] The coils in the second group form a second group of phases, for example star-coupled or delta-coupled, each phase comprising the same number of poles as the phase formed by the first group of coils.

[0057] Each set of coils is powered by a different reversible power converter 14 , 15 .

[0058] Each converter 14 , 15 comprises supply terminals 16 , 17 , 18 , 19 and output terminals 180 , 190 , 200 , 210 , 220 , 230 .

[0059] The first converter 14 is connected to a first power supply network R1 of the helicopter and the second converter 15 is connected to a second power supply network R2 of the helicopter.

[0060] Network R1 and Network R2 are independent, so if one of the networks fails, the other network can still function normally.

[0061] Each phase of the first group of three phases includes connection terminals 24, 25, 26 connected to different output terminals 180, 190, 200 of the first power converter 14, and each phase of the second group of three phases includes connection terminals 27, 28, 29 connected to different output terminals 210, 220, 230 of the second power converter 15.

[0062] Since the architecture of the converters 14 , 15 is identical, only the first converter 14 , which supplies power to the first set of stator coils, is described in detail.

[0063] The first converter 14 comprises as many switching arms 30 , 31 , 32 as the number of phases of the machine 10 .

[0064] Each switching arm 30, 31, 32 comprises a first switching unit 33 comprising, for example, a field effect transistor 34 and a diode 35. The gate of the transistor 35 is controlled by an operating device 240 comprising, for example, a controller.

[0065] The drain of the transistor 34 is connected to the first supply terminal 16 and to the cathode of the diode 35 , and the source of the transistor 34 is connected to the anode of the diode 35 and to the output terminals 180 , 190 , 200 .

[0066] Each switching arm 30 , 31 , 32 further comprises a second switching unit 36 ​​comprising, for example, a field effect transistor 34 and a diode 35 arranged such that the drain of the transistor 34 is connected to the output terminal 180 , 190 , 200 and the cathode of the diode 35 , and the source of the transistor 34 is connected to the anode of the diode 35 and the second supply terminal 17 .

[0067] The first converter 14 further comprises one or more filter capacitors 37 extending between the supply terminals 16 , 17 .

[0068] The machine 10 further comprises a wound rotor 38 comprising two rotor coils 39 , 40 comprising power supply terminals 41 , 42 , 43 , 44 .

[0069] The supply terminals 41 , 42 of the first rotor coil 39 are connected to a third supply network R3 , and the supply terminals 43 , 44 of the second rotor coil 40 are connected to a fourth supply network R4 .

[0070] Networks R3 and R4 are independent, so if one of the networks fails, the other can function normally.

[0071] The first group of stator coils, the second group of stator coils, the first rotor coil 38 and the second rotor coil 40 are arranged in the machine 10 so that the first group of stator coils and the first rotor coil 39 cooperate to transmit mechanical torque on the rotor shaft 11 or transmit electrical power on the connection terminals 24, 25, and 26, and so that the second group of stator coils and the second rotor coil 40 cooperate to transmit mechanical torque on the rotor shaft 11 or transmit electrical power on the connection terminals 27, 28, and 29.

[0072] The control device 12 includes a first converter 14 and a second converter 15 and an operating device 240 .

[0073] The operating device 240 is generated by a controller, for example.

[0074] The first set of stator coils and the first rotor coil 39 form a first electromagnetic transducer 45 (not shown), and the second set of stator coils and the second rotor coil 40 form a second electromagnetic transducer 46 (not shown) independent of the first electromagnetic transducer.

[0075] The operating device 240 operates the power converters 14, 15 so that when one of the first electromagnetic power converter and the second electromagnetic power converter fails, the power converters 14, 15 connected to a set of stator coils of the failed converter do not transmit any electric power, and the other electromagnetic converter operates normally so as to generate mechanical torque or generate electrical energy at the terminals of a set of stator coils of the normally operating electromagnetic converter.

[0076] Furthermore, the operating device 240 disables power supply to the rotor coil of the failed converter to de-energize the rotor of the failed converter, thereby preventing fault propagation due to short-circuit current induced in a set of stator coils of the failed converter.

[0077] The stator coils and rotor coils of the normally functioning electromagnetic converter are powered even if the other electromagnetic converter fails.

[0078] Each electromagnetic converter 45 , 46 is dimensioned so as to ensure a rapid restart of the hybrid turboshaft engine 5 , thereby increasing the reliability of the restart function.

[0079] Because the networks R1, R2, R3 and R4 are independent, the reliability of the restart function is improved.

[0080] Figure 3 A cross section of a machine 10 according to a first example is schematically shown.

[0081] The machine 10 includes a housing 46 that houses the electromagnetic transducers 45 , 46 .

[0082] The first electromagnetic converter 45 comprises a first set of stator coils 47 connected to the connection terminals 24 , 25 , 26 , a magnetic mass 48 surrounding the rotor shaft 11 and accommodating the first rotor coil 39 .

[0083] The second electromagnetic converter 46 includes a second set of stator coils 49 connected to the connection terminals 27 , 28 , 29 , a magnetic mass 50 surrounding the rotor shaft 11 and accommodating the second rotor coil 40 .

[0084] The magnetic masses 48 , 50 of the electromagnetic converters 45 , 46 are mounted in series on the rotor shaft 11 .

[0085] A set of stator coils 47 , 49 forms the stator 13 , and the rotor shaft 11 and the magnetic masses 48 , 50 including the rotor coils 39 , 40 form the rotor 38 .

[0086] The rotor 38 further includes two sets of power supply rings 51 , 52 .

[0087] The first set of conductive rings 51 includes two rings 53 , 54 arranged on the rotor shaft 11 and connected to the first rotor coil 39 .

[0088] Each ring 53 , 54 cooperates with a different brush 55 , 56 of the first set of brushes of the stator 13 .

[0089] Brushes 55 , 56 are connected to the power supply terminals 41 , 42 to supply power to the first rotor coil 39 .

[0090] The second set of rings 52 includes two rings 57 , 58 arranged on the rotor shaft 11 and connected to the second rotor coil 40 .

[0091] Each ring 57 , 58 cooperates with a different brush 59 , 60 of the second set of brushes of the stator 13 .

[0092] The brushes 59 , 60 are connected to the power supply terminals 43 , 44 to supply power to the second rotor coil 40 .

[0093] Figure 4 An electrical diagram of a second example of machine 10 and control device 12 is shown.

[0094] A first power converter 14 and a second power converter 15 are shown.

[0095] The machine 10 comprises a stator 61 including a first set of stator coils and a second set of stator coils (not shown in this figure).

[0096] The coils in the first set of stator coils form three first phases, for example star-coupled or delta-coupled, each phase comprising the same number of poles.

[0097] The coils in the second set of stator coils form three second phases, for example star-coupled or delta-coupled, each phase including the same number of poles as the phase formed by the first set of coils.

[0098] Each set of coils is powered by a different reversible power converter 14 , 15 .

[0099] Output terminals 180 , 190 , 200 of first converter 14 are each connected to connection terminals 62 , 63 , 64 of a different first phase, and output terminals 210 , 220 , 230 of second converter 15 are each connected to connection terminals 65 , 66 , 67 of a different second phase.

[0100] The machine 10 also includes a wound rotor 68 including two rotor coils 69 , 70 , each rotor coil being independently powered by an auxiliary power converter 71 , 72 .

[0101] The auxiliary power converters 71 , 72 are generated by the switching units 30 , 31 and include input terminals 73 , 74 , 75 , 76 .

[0102] The supply terminals 73 , 74 of the first auxiliary power converter 71 are connected to the third network R3 , and the supply terminals 75 , 76 of the second auxiliary power converter 72 are connected to the fourth network R4 .

[0103] The control device 12 includes a first converter 14 and a second converter 15, a first auxiliary converter 71 and a second auxiliary converter 72, and an operating device 250, which operates the gates of the transistors of the first converter 14 and the second converter 15 and the gates of the transistors of the first auxiliary converter 71 and the second auxiliary converter 72, so that the machine 10 transmits mechanical torque on the rotor shaft 11 or generates electrical power at its terminals.

[0104] The operating device 250 is generated by a controller, for example.

[0105] Figure 5 A radial cross section of a second example of a machine 10 is schematically shown.

[0106] The machine 10 includes a housing 80 in which the stator 61 and the rotor 68 are housed.

[0107] The stator 61 comprises two identical magnetic stator half-masses 81 , 82 which extend in the longitudinal direction of the stator 61 and are connected together to form the stator 61 .

[0108] The first set of stator coils is inserted into the first magnetic stator half-mass 81 and comprises nine coils 83 to 91 inserted between the stator teeth of the stator half-mass to extend in the longitudinal direction of the stator and form three poles per phase.

[0109] The first phase of the first stator half mass block 81 includes coils 83, 86 and 89 and is powered by the connecting terminal 62, the second phase of the first stator half mass block 81 includes coils 84, 87 and 90 and is powered by the connecting terminal 63, and the third phase of the first stator half mass block 81 includes coils 85, 88 and 81 and is powered by the connecting terminal 64.

[0110] The second set of stator coils is inserted into the second magnetic stator half-mass 82 and comprises nine coils 92 to 100 inserted between the stator teeth of this stator half-mass to extend in the longitudinal direction of the stator and to form three poles per phase.

[0111] The first phase of the second stator half mass block 82 includes coils 92, 95, 98 and is powered by the connecting terminal 65, the second phase of the second stator half mass block 82 includes coils 93, 96 and 99 and is powered by the connecting terminal 66, and the third phase of the second stator half mass block 82 includes coils 94, 97, 100 and is powered by the connecting terminal 67.

[0112] The windings of the stator half-masses 81 , 82 are distributed so that the torque distribution in the machine 10 can be optimized by damping torque variations.

[0113] Alternatively, the windings of the stator mass halves 81 , 82 are concentric.

[0114] Of course, the first set of stator coils and the second set of stator coils may include more than three phases, and each phase may include more than three poles.

[0115] Furthermore, each pole may be formed from a plurality of stator coils.

[0116] The rotor 68 comprises two identical magnetic rotor half masses 101 , 102 which extend in the longitudinal direction of the rotor and are fixed to the rotor shaft 11 and to each other in order to form the rotor 68 .

[0117] The first magnetic rotor half-mass 101 comprises a first rotor coil 69 wound around a rotor liner of the half-mass 101 .

[0118] The rotor pads are arranged in the half-mass 101 such that they are vertical.

[0119] The turns of the coil 69 arranged on the first pad form a north pole denoted N1 , and the turns arranged on the second pad form a south pole denoted S1 of the first coil 69 , the turns being arranged perpendicularly relative to each other.

[0120] The second magnetic rotor half-mass 102 includes a second rotor coil 70 wound around a rotor liner of the half-mass 102 .

[0121] The rotor pads are arranged in the half-mass 102 such that they are vertical.

[0122] The turns of the coil 70 arranged on the first pad form a north pole denoted N2 and the turns arranged on the second pad form a south pole denoted S2 of the second coil 70 , the turns being arranged perpendicularly relative to each other.

[0123] In the double wound rotor 68 , the poles N1 , S1 , N2 , S2 are arranged perpendicularly with respect to each other.

[0124] The machine 10 also includes a first set of rings 51 and a second set of rings 52 (not shown in the figure), which are arranged on the rotor shaft 11 and cooperate with brushes 55, 56, 59, 60 (not shown in the figure) so that the first set of rings 51 supplies power to the first coil 69 from the first auxiliary converter 71, and so that the second set of rings 52 supplies power to the second coil 70 from the second auxiliary converter 72.

[0125] When the two sets of stator windings are operating normally, the operating device 250 operates the auxiliary converters 71, 72 so that they each deliver a continuous supply current, and also operates the power converters 14, 15 so that the machine 10 delivers mechanical torque on the rotor shaft 11 or generates electrical power at its terminals 61 to 67, which is re-injected by the converters 14, 15 into the helicopter's networks R1, R2.

[0126] When one of the first set of stator windings and the second set of stator windings fails, the operating device 250 operates the power converter 14, 15 connected to the failed set of stator coils so that the converter no longer supplies power to the failed set of stator coils, and the operating device also operates the auxiliary converters 71, 72 so that the amplitude of the current supplying the rotor coils 69, 70 of the rotor half-mass block covering the failed set of stator coils is reduced, so that when the rotor half-mass block covers all of the failed set of stator coils, the control current is substantially zero, and when the rotor half-mass block does not cover the failed set of stator coils, the amplitude of the control current increases.

[0127] The effective value of the control current is non-zero.

[0128] The instantaneous value of the magnetic field generated in the air gap between the failed set of stator coils and the rotor coils of the machine 10 is minimal, thereby preventing the fault from propagating to the properly functioning set of stator coils.

[0129] In order to prevent excessive parasitic short circuit currents from occurring in a failed set of stator coils (which are induced by the magnetization of the air gap of the rotor winding opposite to the rotor winding facing the failed set of stator coils), a dead time may be generated.

[0130] Figure 6 Shows Figure 5 A schematic model of a second example of a machine 10 is shown.

[0131] The two identical magnetic stator half-masses 81 , 82 and the two rotor coils 69 , 70 are powered by a supply current I1 and a supply current I2 , respectively.

[0132] A reference system is defined comprising an origin at the center of the rotor shaft 11 , a first fixed axis X, and a second axis Y passing through the centers of the rotor coils 69 , 70 and defining an angle α with the first axis X.

[0133] Assume that the first stator half mass 81 extends from 0 to π along the first axis X, and the second stator half mass 82 extends from π to 0 along the first axis X.

[0134] Figure 7 The variation over time of the sinusoidal supply currents I1 , I2 delivered by the auxiliary power converter when a fault occurs in the first set of stator coils incorporated in the first half-mass 81 is shown.

[0135] Figure 8 An example of an aircraft 200 of CTOL type is shown, for example a twin-motor aircraft comprising two identical propulsion devices 201 arranged on each side of the longitudinal axis of the aircraft.

[0136] Each propulsion device 201 includes a propeller 202 and Figures 2 to 5 A machine 10 and a control device 12 connected to the machine 10.

[0137] The rotor shaft 11 is connected to the propeller 10 so that the propeller rotated by the electric motor 10 propels the aircraft.

Claims

1. A synchronous electric machine (10) for an aircraft (1, 200), comprising a stator (13, 61) and a wound rotor (38, 68) inserted into the stator, the stator comprising two sets of stator coils (47, 49, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100) intended to be connected to different power converters (14, 15), and the wound rotor comprising a rotor shaft (11) and two rotor coils (39, 40, 69, 70), each rotor coil being intended to be powered by a different supply current (I1, I2), characterized in that The two groups of stator coils are arranged in the stator so that when a first group of stator coils (47) fails, the second group of stator coils (49) cooperates with at least a second rotor coil (40, 70) powered by an associated supply current (I2) to generate electrical energy at terminals of the second group of stator coils or to generate mechanical torque on the rotor shaft, and so that a power converter connected to the first group of stator coils does not deliver any electrical power.

2. The motor according to claim 1, wherein: The two rotor coils (39, 40) are arranged in series on the rotor shaft (11), and the first group of stator coils (47) and the second group of stator coils (49) are arranged in the stator, so that the first rotor coil and the first group of stator coils form a first electromagnetic converter, and the second rotor coil and the second group of stator coils form a second electromagnetic converter.

3. The motor according to claim 1, characterized in that The rotor (68) comprises two identical magnetic rotor half-masses (101, 102) extending in the longitudinal direction of the rotor, and the stator (61) comprises two identical magnetic stator half-masses (81, 82) extending in the longitudinal direction of the stator, each rotor coil is inserted into a different magnetic rotor half-mass, and each group of stator coils is inserted into a different magnetic stator half-mass.

4. The electric machine according to any one of claims 1 to 3, wherein: The rotor (38, 68) comprises two sets of supply rings (51, 52), each set of supply rings being connected to a different rotor coil (39, 40, 69, 70), and wherein the stator comprises two sets of brushes (55, 56, 59, 60), each set of brushes supplying a different set of rings, each set of brushes being intended to be connected to one of the second power converters (14, 15).

5. A propulsion device (201) for an aircraft (200), comprising an electric machine (10) according to any one of claims 1 to 4 and a propulsion propeller (202) connected to the rotor shaft (11).

6. A hybrid turboshaft engine (5) for an aircraft (1), comprising an electric machine (10) according to any one of claims 1 to 4 and a turboshaft engine, the turboshaft engine comprising a gas free turbine (9), the free turbine being additionally connected to the rotor shaft (11) of the electric machine.

7. An aircraft (1, 200) comprising a propulsion device (201) according to claim 5 or a hybrid turboshaft engine (5) according to claim 6.

8. A method for controlling a synchronous electric machine (10) for an aircraft (1, 200), the electric machine comprising a stator (13, 61) and a wound rotor (38, 68) inserted in the stator, the stator comprising two sets of stator coils (47, 49, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100) connected to different power converters (14, 15), and the wound rotor comprising a rotor shaft (11) and two rotor coils (39, 40, 69, 70), each rotor coil being powered by a different supply current (I1, I2), characterized in that The method comprises deactivating a faulty first set of stator coils (47, 83, 84, 85, 86, 87, 88, 89, 90, 91) by operating a power converter (14) connected to the first set so that the converter does not deliver any electrical power to the set of coils, supplying power to a second set of stator coils (49, 92, 93, 94, 95, 96, 97, 98, 99, 100) by an associated power converter (15), and providing at least one power supply to a second rotor coil (40, 70) by an associated supply current (I2) so as to generate mechanical torque on the rotor shaft (11) or generate electrical energy at terminals of the second set of stator coils.

9. The method according to claim 8, wherein the rotor (68) comprises two identical magnetic rotor half-masses (101, 102) extending in the longitudinal direction of the rotor, and the stator (61) comprises two identical magnetic stator half-masses (81, 82) extending in the longitudinal direction of the stator, each rotor coil (69, 70) is inserted into a different magnetic rotor half-mass, and each group of stator coils is inserted into a different magnetic stator half-mass, and the method comprises controlling the supply current (I1, I2) so that the amplitude of the current supplying the rotor coils of the rotor half-mass covering the first group of stator coils is reduced, so that when the rotor half-mass covers all of the first group of stator coils, the control current is substantially zero, and when the rotor half-mass does not cover the first group of stator coils, the amplitude of the control current is increased, and the effective value of the control current is non-zero.

10. The method according to claim 9, wherein: Each supply current (I1, I2) is sinusoidal.

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