AIRCRAFT PROPELLER PITCH ADJUSTMENT SYSTEM

Abstract

The invention relates to a system (100) for adjusting the blade pitch (102) of an aircraft propeller, comprising: - a propeller rotor (104) carrying the blades and designed to rotate relative to a frame (106) of the aircraft; - an electric motor (108), carried by the propeller rotor (104), designed to drive the blades (102) in order to adjust their pitch; and - an electrical network (112) carried by the aircraft frame (106). It further comprises redundant control devices (1141, 1142), carried by the propeller rotor (104) and powered by the electrical network (112) to control the electric motor (108). Figure for the abstract: Fig. 1

Description

Title of the invention: PROPELLER PITCH ADJUSTMENT SYSTEM FOR AN AIRCRAFT Technical field of the invention

[0001] The present invention relates to a system for adjusting the blade pitch of an aircraft propeller. Technological background

[0002] Prior art is known of a system for adjusting the blade pitch of an aircraft propeller, comprising: - a propeller rotor carrying the blades and designed to rotate relative to an aircraft frame; - an electric motor, driven by the propeller rotor, designed to drive the blades in order to adjust their pitch; and - an electrical network supported by the aircraft frame.

[0003] The invention aims to improve the reliability of such a pitch adjustment system. Summary of the invention

[0004] A system for adjusting the blade pitch of an aircraft propeller is therefore proposed, comprising: - a propeller rotor carrying the blades and designed to rotate relative to an aircraft frame; - an electric motor, driven by the propeller rotor, designed to drive the blades in order to adjust their pitch; and - an electrical network supported by the aircraft frame; characterized in that it also includes redundant control devices, carried by the propeller rotor and powered by the electrical network to control the electric motor.

[0005] The invention may further include one or more of the following optional features, according to any technically possible combination.

[0006] Optionally, the pitch adjustment system includes a rotating system for transmitting electrical energy from the electrical network to the control devices.

[0007] Optionally also, the rotating system includes a rotating transformer comprising: - a winding, called fixed, carried by the frame, electrically supplied by the electrical network; and - windings, called rotating, carried by the propeller rotor, to respectively supply the control devices.

[0008] Optionally, the fixed winding and the rotating windings are also arranged axially on a rotation axis of the propeller rotor relative to the frame, one after the other.

[0009] Optionally also, each control device includes: - a rectifier designed to convert an alternating voltage received from one of the respective rotating windings into a direct voltage; and - an inverter designed to convert the direct voltage into commands for the electric motorization.

[0010] Optionally, each control device also includes an electrical energy storage unit between the rectifier and the inverter.

[0011] Optionally also, the electric motorization includes a motor comprising a stator having several polyphase winding systems controlled respectively by the control systems.

[0012] Optionally, the pitch adjustment system also includes a non-reversible motion converter designed to transform a rotational movement of the electric motor into a rotational movement of the blades.

[0013] An aircraft comprising a pitch adjustment system according to the invention is also proposed. Brief description of the figures

[0014] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which: - [Fig. 1] is a cross-sectional view of an example of a system according to the invention for adjusting the blade pitch of an aircraft propeller, - [Fig.2] is a cross-sectional view of an example of a rotating transformer of the pitch adjustment system, - [Fig. 3] is a three-dimensional view of the rotating transformer, - Figure 4 is a cross-sectional view of a part of the system according to the invention of not, - [Fig. 5] is a functional view of the control devices of the pitch adjustment system, - Figure 6 is a simplified view of an electric motorization of the pitch adjustment system. - Figure 7 details the inverters of the control devices, - Fig. 8 is a cross-sectional view of a first example of a converter movement of the pitch adjustment system, - [Fig. 9] is a cross-sectional view of a second example of a motion converter for the pitch adjustment system, and - [Fig. 10] is a cross-sectional view of a third example of a motion converter in the pitch adjustment system. Detailed description of the invention

[0015] With reference to [Fig.1], an example of a system 100 according to the invention for adjusting the pitch of blades 102 of an aircraft propeller will now be described.

[0016] In the present invention, the term propeller also covers any type of blower and the term blade covers any type of blade.

[0017] The system 100 first includes a propeller rotor 104 designed to rotate relative to a frame 106 of the aircraft around a main axis P. The frame 106 is, for example, an engine frame or an aircraft cell.

[0018] The propeller rotor 104 carries the blades 102, the latter being movable relative to the propeller rotor 104 in order to change their pitch, i.e., their orientation. In particular, the blades 102 are movable in rotation about respective orientation axes, for example radial, i.e., perpendicular to the principal axis P and passing through it. In [Fig. 1], only one blade 102 is shown and its orientation axis is perpendicular to the plane of the figure.

[0019] The system 100 further includes an electric motor 108 mounted on the propeller rotor 104. The electric motor 108 is designed to drive the blades 102 in order to adjust their pitch. All the blades 102 can be driven simultaneously, or in groups, or even individually. This last case is useful when the aircraft is a helicopter, where the pitch of each blade 102 must be adjusted according to the angular position of the blade 102.

[0020] The blades 102 are, for example, those of a main rotor or of a tail rotor of a helicopter. Alternatively, the invention can be applied to the turboprop, turbofan or open rotor of an aircraft, such as a conventional horizontal take-off and landing aircraft, or a vertical take-off and landing aircraft (VTOL).

[0021] For example, the system 100 further comprises a motion converter 110 designed to convert a rotational motion supplied by the electric motor 108 into a desired motion of the blades 102. The motion converter 110 is preferably non-reversible, so that in the event of a malfunction of the electric motor 108, the blades 102 cannot move relative to the propeller rotor 104. The non-reversibility is achieved, for example, by providing, in the motion converter 110, a nut / worm gear system or a worm wheel system.

[0022] The system 100 further comprises an electrical network 112 carried by the aircraft frame 106. The electrical network 112 is, for example, direct current and designed to supply a direct current voltage Vdc.

[0023] The system 100 further comprises several control devices 114b 1142 for the electric motor 108. These control devices 114b 1142 are mounted on the propeller rotor 104 and are redundant. This means that each of them is designed to control the electric motor 108 independently of the other(s).

[0024] The control devices 114b 1142 are powered by the electrical network 112 to control the electric motor 108.

[0025] In particular, the system 100 includes a rotating system 116 for transmitting electrical energy from the electrical network 112 to the control devices 114i, 1142. Thus, the rotating system 116 is designed to ensure the transmission of electrical energy between the fixed reference frame 106 of the aircraft and the rotating reference frame of the propeller rotor 104. The rotating system 116 is, for example, a magnetic induction system.

[0026] For example, the rotating system 116 includes a rotating transformer 118. The latter may then include a winding, called the fixed winding 120, carried by the frame 106 and several windings, called rotating windings (two in the illustrated example, designated by reference numerals 122b and 1222), carried by the propeller rotor 104. The fixed winding 120 is designed to receive an alternating voltage Va and is magnetically coupled to all the rotating windings 122b and 1222, so that the rotating windings 122b and 1222 provide respective voltages Val and Va2, resulting from the voltage Va applied to the fixed winding 120. To promote magnetic coupling, the rotating transformer 118 includes, for example, a magnetic circuit 124 (also called a magnetic core) carried by the aircraft frame 106. The fixed winding 120 therefore forms an inductor, while the rotating windings form armatures.

[0027] The control devices 114b 1142 are then respectively connected to the rotating windings 122b 1222 to respectively receive the voltages Val, Va2, in order to respectively provide commands Vcl, Vc2 to the electric motor 108.

[0028] In particular when the electrical network 112 is continuous, the rotating electrical transport system 116 includes an inverter 126 designed to convert the voltage Vdc into the voltage Va applied to the fixed winding 120.

[0029] Preferably, so that the stationary winding 120 produces a magnetic flux passing through the two rotating windings 122b and 1222, the three windings 120, 122b, and 1222 are preferably arranged axially on the main axis P, one after the other. More precisely, the three windings 120, 122b, and 1222 are all centered on the main axis P. Thus, the rotating windings 122b and 1222 are arranged to receive substantially the same excitation magnetic field generated by the stationary winding 120.

[0030] With reference to [Fig. 2], the rotating transformer 118 comprises a fixed support 202 attached to the frame 106 and carrying the fixed winding 120, as well as for example the magnetic core 124. The transformer 118 also includes a movable support 204 attached to the propeller rotor 104 and carrying the rotating windings 122b 1222.

[0031] The environment of the windings 120, 122b 1222 and in particular the supports 202, 204 are preferably made of non-magnetic or para-magnetic materials, for example of magnetic susceptibility less than 103, in order to avoid any magnetic short circuit.

[0032] With reference to [Fig. 3], the magnetic circuit 124 may comprise a plurality of magnetic modules 302, for example, at least three. Twelve magnetic modules 302 are provided in the illustrated example. These magnetic modules 302 are arranged around the main axis P in a corolla shape. Preferably, they are distributed angularly in a regular manner. For example, each module 302 is formed by a closed loop extending along a respective plane 304 containing the main axis P. In the described example, the closed loop is rectangular. This looped shape makes it possible to homogenize the distribution of the magnetic flux. Each magnetic module 302 is, for example, made by one or more stacks of straight magnetic laminations or laminations staggered so as to fit the curve of the fixed winding 120.

[0033] Each control device 114b 1142 is for example designed to receive a setpoint in order to control the electric motor 108 from this setpoint.

[0034] With reference to [Fig. 4], for the transmission of this command, the system 100 may further comprise, mounted on the aircraft frame, a wireless transmitter 402 designed to transmit the command and, for each control device 114b 1142, a wireless receiver 404b 4042 designed to receive the command transmitted by the wireless transmitter 402 and transmit it to the associated control device 114b 1142. Communication between the wireless transmitter 402 and the wireless receivers 404b 4042 is, for example, radio wave or electromagnetic, such as a LiFi communication system using light pulses (e.g., laser) and optical sensors to avoid any risk of electromagnetic compatibility (EMC risk). This communication is, for example, secure (e.g., using a secure communication protocol) and redundant (e.g., via separate and independent components for each of the controllers of each inverter).

[0035] Each control device 114b 1142 can further be designed to control the electric motor 108 from a measurement of the blade pitch 102. Thus, the system 100 includes, for example, a blade position sensor 406, designed to provide the blade pitch measurement 102 to the control devices 114b 1142. This position sensor 406 is, for example, carried by the propeller rotor 104.

[0036] With reference to [Fig. 5], each control device 114b 1142 includes, for example, a rectifier 502b 5022 designed to convert the alternating voltage Val, Va2 associated with a DC voltage, as well as a 504b 5042 inverter designed to convert this DC voltage into the associated Cl, C2 control.

[0037] Each control device 114b 1142 may further include an electrical energy storage battery 506b 5062 carried by the propeller rotor 104, between the rectifier 502i, 5022 and the inverter 504b 5042. This may be, for example, a chemical battery or a capacitive energy storage device. The system 100 is then designed to use the stored electrical energy to meet alternating current demands and / or the most extreme loads, so as not to oversize the power supply system. The system 100 may also be designed, in the event of unavailability of the electrical network 112 (for example, following a fault in the transformer 118), to power the electric motor 108 using the stored electrical energy.In this case, system 100 is designed, for example, to use stored electrical energy to adjust the pitch of the blades 102 to a predefined position, in particular a neutral emergency position allowing the aircraft to benefit from safe propulsion.

[0038] With reference to [Fig. 6], the electric motor 108 comprises, for example, a motor having a stator 602 and a rotor 604, with the stator 602 having several polyphase winding systems, for example three-phase. More specifically, a polyphase system is provided for each control device 114b 1142.

[0039] The motor 602, 604 can be synchronous or asynchronous, for example a reluctance motor such as a radial flux switched variable reluctance motor used in step-by-step mode.

[0040] The rotor 604 can be a salient effect rotor, a permanent magnet rotor, or a hybrid rotor. A wound rotor remains possible, but is not preferred.

[0041] In the described example, two winding systems are provided: windings LAb, LBi, LCi and windings LA2, LB2, LC2. The systems are, in particular, interleaved, meaning that the motor alternately has a winding from each system, i.e., in the illustrated example: LAb then LA2, then LBb then LB2, then LCb then LC2. In the case of three-phase systems, the windings of each system are, for example, angularly offset by 120° from one another. Furthermore, the two three-phase systems are, for example, offset by an angle between 0° and 60°, preferably 60° as in the illustrated example.

[0042] These systems are respectively controlled by the control devices 114b 1142. Thus, each control device 1141, 1142 is designed to respectively supply phase voltages VAb VBb VCb VA2, VB2, VC2 to the windings LAb LBi , LCb LA2, LB2, LC2 of the associated system, from the associated alternating voltage Val, Va2.

[0043] Thus, the electric motor 108 is capable of operating in the event of a malfunction partial operation, such as: a short circuit on one of the phases of the motor, a malfunction on one of the inverters 504b 5042, a malfunction on one of the rotating windings 122b 1222 of the transformer 118.

[0044] With reference to [Fig. 7], each inverter 504b 5042 comprises, for example, a switching power circuit 702b 7022, and a control device 704b 7042 for the power circuit 702b 7022, for example based on the step measurement P of the sensor 406 and / or the setpoint C received by the corresponding receiver 404b 4042. The control is, for example, performed by pulse-width modulation (PWM) or full-wave modulation.

[0045] For example, each power circuit 702b 7022 includes a full switching bridge for each winding of the system controlled by the power circuit 702b 7022 under consideration. The control device 704b 7042 can then be designed to switch the full bridges.

[0046] With reference to [Fig. 8], in a first embodiment, the motion converter 110 comprises, for example, a cylinder 802, for example electric, having a rod 804 that moves in translation according to the rotation of the motor 108. The cylinder 802 comprises, for example, a worm gear onto which a nut, fixed to the rod 804, is screwed. The motion converter 110 further comprises a connecting rod 806 interposed between the rod 804 and the blade 102.

[0047] A reducer 808 and / or an elastic coupling 810 may be provided between the motor 108 and the cylinder 802.

[0048] With reference to [Fig.9], in a second embodiment, the motion converter 110 includes, for example, a support 902 that is movable and rotates relative to the propeller rotor 104. In this case, the electric motor 108 and the cylinder 802 are fixed to the support 902, and the blade 102 is directly connected to the rod 804 of the cylinder 802.

[0049] With reference to [Fig. 10], in a third embodiment, the cylinder 802 can be directly rotatable. For example, its worm gear can drive a toothed wheel 1002 fixed to the blade 102.

[0050] It should also be noted that the invention is not limited to the embodiments described above. It will indeed be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them.

[0051] In particular, alternatively, the electric motor 108 could comprise two motors, each having a stator and a rotor. Alternatively, the electric motor 108 could comprise one motor with two stators and a single rotor. These motors are preferably switched-reluctance motors, but they can also be DC motors, either synchronous or asynchronous. In this case, The power circuits 7021, 7022 can be half-bridge switching, and the control devices 7041, 7042 can be designed to control the half-bridges by a stroke servo.

[0052] Furthermore, instead of the rotating transformer 118, the rotating electrical transmission system 116 could include a rotating commutator, even if the latter is sensitive to vibrations. For example, the DC voltage Vdc could be directly conveyed by two commutators, without requiring the upstream inverter 126 and the downstream rectifiers 502i, 5022. In addition, motor control signals could be conveyed by six commutators.

[0053] Furthermore, the blade position sensor 406 102 can be a translational position sensor on the cylinder 802.

[0054] In the detailed presentation of the invention given above, the terms used shall not be interpreted as limiting the invention to the embodiments set forth in this description, but shall be interpreted as including all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

Demands

1. A propeller pitch control system (100) for an aircraft propeller, comprising: - a propeller rotor (104) carrying the blades and designed to rotate relative to an aircraft frame (106); - an electric motor (108), carried by the propeller rotor (104), designed to drive the blades (102) to adjust their pitch; - an electrical network (112) carried by the aircraft frame (106); - redundant control devices (114b 1142), carried by the propeller rotor (104) and powered by the electrical network (112) to control the electric motor (108); and - a rotating system (116) for transmitting electrical power from the electrical network (112) to the control devices (114b 1142); characterized in that the rotating system (116) includes a rotating transformer (118) comprising: - a winding (120), said to be fixed, carried by the frame (106), electrically supplied by the electrical network (112);and - windings (122b 1222), called rotating windings, carried by the propeller rotor (104), to respectively power the control devices (114b 1142); the fixed winding (120) being magnetically coupled to all the rotating windings (122b 1222).

2. Pitch adjustment system (100) according to claim 1, wherein the fixed winding (120) and the rotating windings (122b 1222) are arranged axially around an axis of rotation (P) of the propeller rotor (104) relative to the frame (106), one after the other along this axis of rotation (P).

3. Pitch adjustment system (100) according to claim 1 or 2, wherein each control device (114b 1142) comprises: - a rectifier (502b 5022) designed to convert an alternating voltage (Val, Va2) received from one of the respective rotating windings (122b 1222) into a direct voltage; and - an inverter (504b 5042) designed to convert the direct voltage into commands (Cl, C2) for the electric motor (108).

4. Pitch adjustment system (100) according to claim 3, wherein each control device (114b 1142) includes an electrical energy storage device (506b 5062) between the rectifier (502b 5022) and the inverter (504b 5042).

5. Pitch adjustment system (100) according to any one of claims 1 to 4, wherein the electric drive (108) comprises a motor having a stator having several polyphase winding systems (LAb LBi, LCi, LA2, LB2, LC2) controlled respectively by the control systems (114b 1142).

6. Pitch adjustment system (100) according to any one of claims 1 to 5, further comprising a non-reversible motion converter (110) designed to transform a rotational motion of the electric motor (108) into a rotational motion of the blades (102).

7. Aircraft comprising a pitch adjustment system (100) according to any one of claims 1 to 6.

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