Turbomachine comprising an electric machine provided with a fixed winding, an excitation winding and a rotary winding which are arranged radially

Abstract

Turbomachine (50) for an aircraft (100) comprising at least: - a rotary part (Pt) rotating about an axis of rotation (A), - a fixed part (Pf) incapable of rotating about the axis of rotation (A) with respect to the rotary part (Pt), the fixed part (Pf) comprising a fan casing (52), - an electric machine (M1, M2, M3) suitable for operating in generator mode, the turbomachine (50) being characterized in that the electric machine (M1, M2, M3) comprises at least one fixed winding (10) and one excitation winding (20), which are positioned on the fixed part (Pf) of the turbomachine (50), and at least one rotary winding (30) positioned on the rotary part (Pt) of the turbomachine (50), the fixed winding (10), the excitation winding (20) and the rotary winding (30) being arranged radially around the axis of rotation (A).

Description

[0001] DESCRIPTION

[0002] TITLE: Turbomachine comprising an electric machine provided with a fixed winding, an excitation winding and a rotating winding arranged radially

[0003] Technical Field

[0004] The invention relates to the field of aircraft turbomachines and more particularly to a turbomachine comprising an electric machine and an aircraft comprising such a turbomachine.

[0005] In this presentation, the term "aircraft turbomachine" designates a set of turbomachines or gas turbine devices producing motive power, dedicated to aircraft propulsion and equipped with a nacelle or not. Among these devices, a distinction is made in particular between turbojets providing the thrust necessary for propulsion by reaction to the high-speed ejection of gas, and turboshafts in which the motive power is provided by rotation of an engine shaft. For example, turboshafts are used as helicopter engines. Turboprops (turboshafts driving a propeller) are turboshafts used as aircraft engines.

[0006] State of the prior art

[0007] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0008] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the factors impacting all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of aircraft.

[0009] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity. This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter onboard equipment, the development of the use of electric technologies to provide propulsion, and, as essential complements to technological progress, aeronautical biofuels.

[0010] There are devices arranged in a rotating part of a turbomachine, for example a rotor of a turbine, such as a device for controlling a pitch of the blades of a fan, devices for protecting small pitch of fan blades, devices for de-icing a cone or blades of the fan, etc. Such devices can be powered by electrical energy.

[0011] For this, it is known to have an electrical machine in a fixed part of a turbomachine and to transmit the electrical energy into the rotating part. This can, for example, be achieved by means of a slip ring. However, such a slip ring can be fragile and require regular maintenance operations.

[0012] A fixed part is a device of the turbomachine configured to be stationary or fixed in rotation relative to an aircraft on which the turbomachine is installed. The fixed part includes, for example, the fan casing.

[0013] The rotating part refers to the devices of the turbomachine configured to be mobile in rotation relative to the aircraft on which the turbomachine is installed.

[0014] The transmission of electrical energy to the rotating part can also be achieved by a rotating transformer associated with an inverter resulting in an increase in mass and volume of the turbomachine. In addition, an electromagnetic field generated by the rotating transformer can disturb measuring devices of the turbomachine such as a speed sensor or a fan pitch sensor.

[0015] There is therefore a need for a reliable, low-mass and small-sized power supply in the rotating part.

[0016] Statement of the invention

[0017] One embodiment relates to a turbomachine for an aircraft, the turbomachine extending along an axis of rotation and comprising at least:

[0018] - a part rotating around the axis of rotation,

[0019] - a fixed part rotating around the axis of rotation relative to the rotating part, the fixed part comprising a fan casing,

[0020] - an electrical machine adapted to operate in generator mode, the turbomachine being characterized in that the electrical machine comprises at least one fixed winding and one excitation winding, which are positioned on the fixed part of the turbomachine, and at least one rotating winding positioned on the rotating part of the turbomachine, the fixed winding, the excitation winding and the rotating winding being arranged radially around the axis of rotation.

[0021] Generally speaking, the axial direction corresponds to the direction of the axis of rotation of the turbomachine (or of a fan disk), and a radial direction is a direction perpendicular to the axis of rotation.

[0022] Furthermore, upstream and downstream are defined relative to a normal gas flow direction (from upstream to downstream) through the turbomachine.

[0023] In some embodiments, the turbomachine comprises at least one turbine, at least one compressor and at least one fan which are positioned in the axial direction, i.e. linearly along the axis of rotation.

[0024] The turbomachine may also include a nacelle.

[0025] The turbine, compressor and nacelle comprise elements or devices forming the fixed part of the turbomachine relative to the aircraft, when the turbomachine is fixed to the aircraft via the nacelle. In other words, the fixed part is integral with the nacelle.

[0026] The turbine, compressor, and fan comprise moving elements that rotate around the axis of rotation. These elements form the rotating part of the turbomachine. These elements have relative movement with respect to the nacelle.

[0027] By means of an expansion of the gases from a combustion chamber, the turbomachine drives the rotation axis on which the rotating part is fixed.

[0028] The turbomachine also comprises at least one electric machine according to the subject of the present disclosure. The electric machine can be used in generator mode in which it produces electrical energy, or in motor mode in which it consumes energy in order to rotate the rotation axis.

[0029] More precisely, the electric machine is a rotating machine that can convert mechanical energy into alternating current electrical energy and vice versa.

[0030] Generally speaking, a winding can refer to an electrical coil.

[0031] The machine according to the subject of the present disclosure comprises at least one fixed winding and one excitation winding, both of which are positioned on the fixed part of the turbomachine.

[0032] The machine also includes at least one rotating winding positioned on the rotating part of the turbomachine.

[0033] The fixed winding, the excitation winding and the rotating winding are arranged radially around the axis of rotation.

[0034] The fixed winding, the excitation winding and the rotating winding are positioned concentrically around the axis of rotation so that electrical inductions are possible between each of the windings. In an operation of the electric machine according to the motor mode, the fixed winding is an inductor of the machine, that is to say its function is to induce an electromagnetic field in the rotating winding positioned on the rotating part. For this, the fixed winding is electrically powered, in particular by a three-phase current. An electromagnetic field created by the fixed winding induces an electromagnetic field in the rotating winding, which has the effect of driving the rotating part in rotation. The rotating winding is then an armature of the electric machine.

[0035] The motor mode of the electric machine can be used during a start-up of the turbomachine, or during a maintenance operation requiring rotation of the rotating part of the turbomachine, or to inject mechanical torque onto a shaft of the turbomachine to which the electric machine is coupled during any phase of flight of the aircraft. In an operation of the machine in a generator mode, the rotating winding is an armature and an inductor of the machine. Indeed, on the one hand it is excited by the excitation winding so that it produces a three-phase electric current in the rotating part, and on the other hand it induces an electromagnetic field in the fixed winding positioned on the fixed part, so that the fixed winding generates a three-phase electric current in the fixed part.The rotating winding delivers a variable voltage whose effective value and frequency vary with a supply voltage of the excitation winding.

[0036] The electric current generated by the fixed winding or the rotating winding is a sinusoidal alternating current.

[0037] The electric machine therefore has several functions depending on whether it operates in motor mode or in generator mode.

[0038] The subject matter of this disclosure may also exhibit one or more of the following characteristics, taken alone or in combination.

[0039] According to one embodiment, the turbomachine may comprise on the one hand a high pressure body comprising a high pressure compressor and a high pressure turbine, and on the other hand a low pressure body comprising a low pressure compressor and a low pressure turbine.

[0040] According to one embodiment, the turbomachine also comprises an intermediate body comprising an intermediate pressure compressor and an intermediate pressure turbine.

[0041] According to one embodiment, the electric machine is positioned between the blower and the compressor.

[0042] According to one embodiment, the electric machine is positioned between the blower and a reduction gearbox.

[0043] According to one embodiment, the electric machine is positioned between a reduction gearbox and the compressor. Thus, the electric machine has a higher operating speed and therefore better efficiency.

[0044] According to one embodiment, the rotating winding is positioned on a low pressure shaft of the turbomachine.

[0045] According to one embodiment, the turbomachine comprises at least one electrical power network positioned in the rotating part, said at least one electrical power network being connected to the at least one rotating winding, and configured to circulate an electric current of power greater than or equal to 10 kW and less than or equal to 50 kW.

[0046] The electrical machine, and more specifically the rotating winding, is sized to supply the power electrical current to the power electrical network which is positioned in the rotating part.

[0047] The power electric current is generated directly in the rotating part by the electric machine.

[0048] According to one embodiment, the at least one electrical power network is configured to power at least one electrical device of the turbomachine which is positioned on the rotating part.

[0049] The main purpose of this disclosure is to generate an electric current in the rotating part in order to power functions, also called electrical devices, of the turbomachine present in the rotating part. In this way, it is not necessary to pass the current from the fixed part to the rotating part. An efficiency, weight and volume of the turbomachine are improved.

[0050] An electrical device is any element of the turbomachine that consumes electricity. The functions of the turbomachine implemented electrically can also be referred to as "electrical loads". A device can perform a physical action on the turbomachine, such as heating, or a regulation or control action.

[0051] However, although the purpose of the present disclosure is to generate an electric current in the rotating part, the electrical machine according to the invention also generates an electric current in the fixed part as detailed above. The purpose of the electric current generated in the fixed part is to power electrical elements positioned in the fixed part.

[0052] According to one embodiment, the at least one electrical device of the turbomachine positioned in the rotating part is a device for controlling a pitch of the blades of a fan, devices for protecting the small pitch of the blades of the fan, devices for de-icing a cone or the blades of the fan.

[0053] For example, defrosting a fan cone or blades requires an electrical power of approximately 30kW.

[0054] According to one embodiment, the electrical machine is a wound rotor machine. According to one embodiment, the fixed winding and the excitation winding are electrically connected such that a supply electric current generated by the fixed winding can energize the excitation winding.

[0055] In the generator mode, the rotating winding induces an electromagnetic field in the fixed winding positioned on the fixed part so that the fixed winding generates a three-phase electric current in the fixed part. This electric current can then supply the excitation winding of the electric machine. This is called self-supply. The frequency of the voltage of the electric current generated by the fixed winding then depends on a rotation speed of the rotating part.

[0056] According to one embodiment, the fixed winding is electrically connected to a general electrical network positioned on the fixed part.

[0057] The general electrical network corresponds to an electrical network of the turbomachine, and more generally of the aircraft, which supplies devices in the fixed part such as for example a power supply for the flight controls, wing anti-icing, a power supply for the cabin air conditioning system, lighting in an aircraft cabin, or even a power supply for the cockpit.

[0058] This provides power supply redundancy on the general electrical network. According to one embodiment, the excitation winding comprises a DC / DC converter or a DC / AC converter.

[0059] According to one embodiment, the turbomachine comprises a mechanical element for separating and disconnecting the electrical machine from a shaft of the turbomachine.

[0060] In fact, in the event of an electrical failure of the electrical machine or the power electrical network, it is necessary to have an element allowing the electrical machine to be mechanically disconnected.

[0061] According to one embodiment, the at least one electrical machine is positioned inside the fan housing.

[0062] According to one embodiment, the mechanical separation element may be a dog clutch. Another aspect of the invention relates to an aircraft comprising a turbomachine according to any one of the embodiments of the present disclosure.

[0063] Brief description of the drawings

[0064] The object of the present disclosure will be better understood, thanks to the following description, which relates to several embodiments, given as non-limiting examples and explained with reference to the attached schematic drawings, in which:

[0065] [FIG. 1] is a representation of an aircraft; [FIG. 2] is a schematic representation of an architecture of a turbomachine according to an example of the subject of this presentation;

[0066] [FIG. 3] illustrates one embodiment of the subject of this disclosure.

[0067] Description of the embodiments

[0068] Figure 1 represents an aircraft 100, in this example an airplane, equipped with two turbomachines 50, in this example two propulsion units or two turbojets 50, namely one turbomachine 50 per wing 101. A single turbomachine 50 and a single wing 101 are represented in Figure 2. According to a variant, the aircraft 100 can be equipped with more than one turbomachine 50 per wing 101, each wing 101 being provided with the same number of turbomachines 50.

[0069] Figure 2 represents a schematic view, in section along plane II of figure 1, of an architecture of the turbomachine 50 according to the subject of the present presentation.

[0070] The turbomachine 50 includes a fan, also called a blower 52, which is positioned in a fan housing and a gas generator 54.

[0071] In this example, the gas generator 54 comprises from upstream to downstream, the gases flowing within the turbomachine 50 from upstream to downstream, a compressor 54A (or compressor section 54A), a combustion chamber 54B, and a turbine 54C (or turbine section 54C).

[0072] The fan 52 can be driven in rotation by a shaft of the gas generator 54, for example directly by a shaft A of a low-pressure body, or by means of a reduction gear box Gb also called RGB (an English acronym for “Reduction Gear Box”) mechanically coupled to the shaft A of the low-pressure body. The reduction gear box Gb makes it possible to reduce the rotation speed of the fan 52 relative to that of the shaft A of the low-pressure body.

[0073] The gas generator 54 may be of the double-body type and comprise a low-pressure body and a high-pressure body.

[0074] The low pressure body may comprise a low pressure compressor 62A rotatably coupled with a low pressure turbine 66A via a low pressure shaft A.

[0075] The high-pressure body may comprise a high-pressure compressor 62B disposed downstream of the low-pressure compressor 62A and upstream of the combustion chamber 54B, and a high-pressure turbine 66B, disposed downstream of the combustion chamber 54B and upstream of the low-pressure turbine 66A, and rotatably coupled with the high-pressure compressor 62B via a high-pressure shaft B. The compressor 54A of the gas generator 54 may comprise the low- and high-pressure compressors 62A and 62B. The turbine 54C of the gas generator 54 may comprise the low- and high-pressure turbines 66B and 66A.

[0076] Figure 2 is schematic, each compressor and each turbine being able to have one or more stages, each stage comprising a moving wheel and a stator.

[0077] The turbomachine 50 comprises elements that are mobile in rotation, hereinafter referred to as the rotating part Pt, around an axis of rotation, in a nacelle of the turbomachine 50. The nacelle is configured to be fixed on the aircraft 100. Hereinafter, the fixed part Pf refers to elements of the high-pressure body, of the low-pressure body that are fixed relative to the nacelle. Figure 2 illustrates the positioning of electrical machines M1, M2, M3 connected to a general electrical network 4 of the turbomachine, and more generally of the aircraft 100. The general electrical network 4 supplies devices in the fixed part Pf such as, for example, a power supply for the flight controls, wing anti-icing, a power supply for the cabin air conditioning system, lighting for a cabin of the aircraft, or a power supply for the cockpit.

[0078] A first electrical machine M1 is positioned between the blower 52 and the compressor 54A of the gas generator 54. More specifically, the electrical machine M1 is positioned axially (along the axis of rotation A) between the blower 52 and the reduction gearbox Gb or alternatively positioned axially between the reduction gearbox Gb and the compressor 54A. The electrical machine M1 will be described more precisely with reference to FIG. 3.

[0079] A second electric machine M2 is positioned downstream of the turbine 54C and a third electric machine M3 is positioned at the high pressure compressor 62B.

[0080] The electrical machines M1, M2 and M3 produce an electric current intended to be consumed in the rotating part Pt of the turbomachine 50 or to be transmitted to the general electrical network 4.

[0081] Having several electrical machines M1, M2, M3 makes it possible to reduce the dimensioning of each of the electrical machines M1, M2, M3. Thus, they are more easily integrated into the overall architecture of the turbomachine. Another advantage of positioning several electrical machines M1, M2, M3 is, on the one hand, to have redundancy and therefore better overall reliability of the general electrical network 4, and on the other hand to be able to install simple electrical machines.

[0082] More particularly, an embodiment of the turbomachine 50 according to the subject of the present disclosure is described with reference to FIG. 3.

[0083] The turbomachine 50 comprises an electric machine M1 which comprises elements positioned on the rotating part Pt and others on the fixed part Pf of the turbomachine. On the fixed part Pf, the electric machine M1 comprises at least one fixed winding 10 and one excitation winding 20.

[0084] The rotating part Pt of the electrical machine M1 comprises at least one rotating winding 30.

[0085] The fixed winding 10, the excitation winding 20 and the rotating winding 30 are arranged radially around the axis of rotation.

[0086] The fixed winding 10, the excitation winding 20 and the rotating winding 30 are positioned concentrically around the axis of rotation so that electrical inductions are possible between each of the windings 10, 20, 30.

[0087] The fixed winding is electrically connected to the general electrical network 4 positioned on the fixed part Pf.

[0088] Furthermore, the fixed winding 10 and the excitation winding 20 are electrically connected by an electrical connection 41 so that a supply electric current generated by the fixed winding 10 can supply the excitation winding 20.

[0089] The fixed winding 10 is connected to an AC / DC converter 11.

[0090] The excitation winding 20 comprises a DC / DC converter 21 or a DC / AC converter. The rotating winding 30 is arranged on the low-pressure shaft of the turbomachine. The rotating winding 30 is connected via a power electrical network 3 to a six-diode rotating rectifier 31.

[0091] The power electrical network 3 is configured to circulate an electric current of power greater than or equal to 10 kW and less than or equal to 50 kW so as to supply at least one electrical device F 1 of the rotating part Pt, which may be for example a device for controlling a pitch of the blades of a fan, devices for protecting the small pitch of the blades of the fan, devices for defrosting a cone or the blades of the fan.

[0092] In an operation of the electric machine in a motor mode, the fixed winding 10 is an inductor of the machine, that is to say its function is to induce an electromagnetic field in the rotating winding 30 positioned on the rotating part Pt. For this, the fixed winding 10 is electrically powered, in particular by a three-phase current via the general electrical network 4. An electromagnetic field created by the fixed winding 10 induces an electromagnetic field in the rotating winding 30 which has the effect of driving the rotating part Pt in rotation. The rotating winding 30 is then an armature of the machine.

[0093] The motor mode of the electric machine can be used during a start-up of the turbomachine 50 or during a maintenance operation requiring rotation of the rotating part Pt of the turbomachine 50 or even to inject mechanical torque onto a shaft of the turbomachine 50 to which the electric machine is coupled during any flight phase of the aircraft. In an operation of the machine in a generator mode, the rotation axis is driven in rotation by the combustion chamber 54B. The rotating winding 30 is then an armature and an inductor of the machine. Indeed, on the one hand it is excited by the excitation winding 20 so that it produces a three-phase electric current in the rotating part Pt, and on the other hand it induces an electromagnetic field in the fixed winding 10 positioned on the fixed part Pf so that the fixed winding 10 generates a three-phase electric current in the fixed part Pf.The rotating winding 30 delivers a variable voltage whose effective value and frequency vary with a supply voltage of the excitation winding 20.

[0094] In the generator mode, the rotating winding 30 induces an electromagnetic field in the fixed winding 10 positioned on the fixed part Pf so that the fixed winding 10 generates a three-phase electric current in the fixed part Pf. This electric current can then supply the excitation winding 20 of the electric machine. This is called self-supply. The frequency of the voltage of the electric current generated by the fixed winding 10 then depends on a rotation speed of the rotating part Pt.

[0095] The electric current generated by the fixed winding 10 or the rotating winding 30 is a sinusoidal alternating current.

[0096] The electric machine therefore has several functions depending on whether it operates in motor mode or in generator mode.

[0097] Finally, the turbomachine 50 may comprise a mechanical element for separating and disconnecting the electrical machine M1 relative to a shaft A of the turbomachine 50. For example, the mechanical element for separating and disconnecting the electrical machine is positioned in the rotating part of the turbomachine 50.

[0098] In fact, in the event of an electrical failure of the electrical machine M1 or of the power electrical network 3, it is necessary to have an element allowing the electrical machine M1 to be mechanically disconnected.

[0099] The mechanical separating element can be a dog clutch.

[0100] Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0101] It is also obvious that all the characteristics described with reference to a method are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims

CLAIMS 1. Turbomachine (50) for an aircraft (100), the turbomachine (50) extending along an axis of rotation (A) and comprising at least: - a rotating part (Pt) around the axis of rotation (A), - a fixed part (Pf) rotating around the axis of rotation (A) relative to the rotating part (Pt), the fixed part (Pf) comprising a fan casing (52), - an electrical machine (M1, M2, M3) adapted to operate in generator mode, the turbomachine (50) being characterized in that the electrical machine (M1, M2, M3) comprises at least one fixed winding (10) and one excitation winding (20), which are positioned on the fixed part (Pf) of the turbomachine (50), and at least one rotating winding (30) positioned on the rotating part (Pt) of the turbomachine (50), the fixed winding (10), the excitation winding (20) and the rotating winding (30) being arranged radially around the axis of rotation (A), the turbomachine also comprising at least one electrical power network (3) positioned in the rotating part (Pt), said at least one electrical power network (3) being connected to the at least one rotating winding (30), the at least one electrical power network (3) being configured to power at least one electrical device (F1) of the turbomachine (50) which is positioned on the rotating part (Pt).

2. Turbomachine according to claim 1, in which the rotating winding (30) is positioned on a low pressure shaft (A) of the turbomachine (50).

3. Turbomachine (50) according to any one of claims 1 or 2, in which the at least one electrical device (F1) of the turbomachine (50) positioned in the rotating part (Pt) is a device for controlling a pitch of the blades of a fan (52), small pitch protection devices for the blades of the fan (52), de-icing devices for a cone or the blades of the fan (52).

4. Turbomachine (50) according to any one of the preceding claims, in which the electric machine (M1, M2, M3) is a wound rotor machine.

5. Turbomachine (50) according to any one of the preceding claims, in which the fixed winding (10) and the excitation winding (20) are electrically connected (41) so that an electric supply current generated by the fixed winding (10) can supply the excitation winding (20).

6. Turbomachine (50) according to any one of the preceding claims, in which the excitation winding (20) comprises a DC / DC converter (21) or a DC / AC converter.

7. Turbomachine (50) according to any one of the preceding claims, comprising a mechanical element for separating and disconnecting the electrical machine from a shaft (A) of the turbomachine (50).

8. Aircraft (100) comprising a turbomachine (50) according to any one of the preceding claims.

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