aircraft electrical power system

Abstract

An electrical power system (24) for an aircraft, the electrical power system (24) comprising: a generator (26) configured to convert a first mechanical energy supplied by a turbomachine (1) into a first electrical energy, a first electrical connection adapted to transmit the first electrical energy to a first electrical network (20) being or comprising an emergency network critical for the safety of the aircraft, a generation system (30) configured to convert a second mechanical energy supplied by the turbomachine (1) into a second electrical energy and being galvanically isolated from the first electrical network (20) by a switch (38) configurable in: a first position in which the switch (38) selectively transmits the first electrical energy to a second electrical network (22) for the aircraft separate from the first electrical network (20),and a second position in which the switch (38) selectively transmits the second electrical energy to the second electrical network (22). Figure for the abstract: Fig. 1,

Description

Title of the invention: electrical power system for aircraft FIELD OF THE INVENTION

[0001] The present invention relates to an electrical power supply system for an aircraft. STATE OF THE ART

[0002] It is known to use a generator to convert mechanical energy obtained in a turbomachine of an aircraft into electrical energy, and to use this electrical energy to power electrical loads on board this aircraft.

[0003] Certain electrical loads are critical to the safety of an aircraft. These critical loads must always have electricity on board to control the aircraft, otherwise it will crash.

[0004] In addition, the ever-increasing electrification of aircraft leads to the consideration of new significant electrical loads: electric air conditioning and electric defrosting (already introduced on the Boeing 787), etc. requiring high power of several tens to a hundred kilowatts.

[0005] It is important that such critical electrical loads are not subjected to a surge that could damage them. Such a surge can typically be caused by lightning striking the generator or any other part of the electrical network. Statement of the invention

[0006] An aim of the invention is to define an electrical power supply architecture for aircraft with modular operation, and limiting the risks of damage to certain critical functions of an aircraft caused by an electrical failure or malfunction.

[0007] To this end, according to a first aspect, there is proposed an electrical power supply system for an aircraft, the electrical power supply system comprising: - a generator configured to convert a first mechanical energy supplied by a turbomachine into a first electrical energy, - a first electrical connection adapted to transmit the first electrical energy to a first electrical network for the aircraft, the first electrical network being or comprising an emergency network which is critical for the safety of the aircraft, - a generation system configured to convert a second mechanical energy supplied by the turbomachine into a second electrical energy, - a switch configurable in: i) a first position in which the switch selectively transmits the first electrical energy to a second network electrical power for the aircraft separate from the first electrical network, and ii) a second position in which the switch selectively transmits the second electrical power to the second electrical network, wherein the switch is configured to galvanically isolate the second generation system from the first electrical network, in particular in the first position and in the second position.

[0008] The switch allows modular operation, as it allows the second electrical network to be powered by either the generator or the generation system, depending on its position.

[0009] The safety of the proposed system is improved by the fact that the first electrical network is always powered by the generator, and is galvanically isolated from the generation system. Thus, when the generation system is the victim of an electrical incident, for example caused by lightning, this electrical incident does not affect the first electrical network whose functions are critical for the safety of the aircraft.

[0010] The system according to the first aspect may further comprise the following features, taken alone or in combination whenever technically possible.

[0011] Preferably, the generator is at a first voltage and the generation system is at a second voltage greater than or equal to the first voltage.

[0012] Preferably, the generator is suitable for being mounted on a high pressure body of the turbomachine.

[0013] Preferably, the generation system comprises a generator suitable for being mounted on a low pressure body of the turbomachine.

[0014] Preferably, the generation system comprises a generator suitable for being mounted on a high pressure body of the turbomachine.

[0015] Preferably, the generation system comprises a first generator suitable for being mounted on a low pressure body of the turbomachine, and a second generator suitable for being mounted on a high pressure body of the turbomachine, the first generator and the second generator being interconnected so as to each contribute to generating the second electrical energy.

[0016] Preferably, the first electrical network comprises at least one of the following equipment: an electric flight control for the aircraft, a navigation system for the aircraft, a communication system for the aircraft.

[0017] Preferably, the second electrical network comprises at least one of the following equipment: an air conditioning system for the interior of the aircraft, a de-icing system for the aircraft.

[0018] Preferably, the system comprises a control unit configured to switch the switch from the second position to the first position upon detection of a failure of the generation system.

[0019] There is further provided, according to a second aspect, an aircraft comprising: - a turbomachine, - a first electrical network being or comprising an emergency network providing a critical function for the safety of the aircraft, - a second electrical network separate from the first electrical network, - a system according to the first aspect for electrically supplying the first electrical network and the second electrical network from the turbomachine.

[0020] The aircraft is preferably hybrid-powered. DESCRIPTION OF FIGURES

[0021] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0022] [Fig.l] is a longitudinal sectional view of a turbomachine.

[0023] [Fig.2] is a block diagram representing electrical networks, the turbomachine of [Fig.l], and a system for supplying electricity to these networks according to an embodiment in a first state.

[0024] [Fig. 3] is a block diagram representing electrical networks, the turbomachine of [Fig. 1], and an electrical supply system for these networks according to an embodiment in a second state.

[0025] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0026] With reference to [Fig.l], an aircraft such as an airplane, a helicopter, a multicopter or any other type of aircraft, comprises a turbomachine 1.

[0027] The turbomachine 1 comprises a casing 2, a fan 3, a low pressure body 4, and a high pressure body 6.

[0028] The low pressure body 4 is rotatable relative to the casing 2 about an axis (represented in [Fig.l] by a dotted horizontal line). In a known manner, the low pressure body 4 comprises a low pressure compressor 8 and at least one low pressure turbine 10 mounted on a first shaft called the low pressure shaft. The low pressure body 4 has the particular function of driving a fan of the turbomachine 1 in rotation.

[0029] Similarly, the high pressure body 6 is rotatable relative to the casing 2, and relative to the low pressure body 4 around the aforementioned axis. The high pressure body 6 comprises a high pressure compressor 12 and at least one high pressure turbine 14 mounted on a second shaft called the high pressure shaft.

[0030] The casing 2 extends around the low pressure body 4 and the high pressure body 6. The casing 2 delimits a combustion chamber 16 located between the high pressure compressor 12 and the or each high pressure turbine 14. The casing 2 also delimits a nozzle 18 located downstream of the or each low pressure turbine 10.

[0031] Along the axis of the turbomachine 1, we find in this order: the fan 3, the low pressure compressor 8, the high pressure compressor 12, the combustion chamber 16, the high pressure turbine 14, the low pressure turbine 10 and the nozzle 18.

[0032] This form of turbomachine 1 is known. For the remainder of the description, it will be noted in particular that the rotation of the high pressure body 6 and the low pressure body 4 relative to the casing 2 is driven by the injection of fuel which enters into combustion in the combustion chamber 16 and which drives the rotation of the turbines 10, 14. These rotational movements generate mechanical energy allowing the propulsion of the aircraft.

[0033] With reference to [Fig.2], the aircraft also comprises different electrical networks 20, 22.

[0034] A first electrical network 20 of the aircraft is or comprises a network called "emergency network" or "emergency network" in the literature, which is critical for the safety of the aircraft. By this expression, it is meant that a failure of this emergency network while the aircraft is in flight would result in a crash of the aircraft.

[0035] The first electrical network 20 comprises at least one of the following equipment: at least one electric flight control for the aircraft, a navigation system for the aircraft, a communication system for the aircraft.

[0036] A second electrical network 22 of the aircraft comprises other less critical equipment of the aircraft, generally located on a right half or a left half of the aircraft. For example, if the turbomachine 1 is located on the left wing of the aircraft, the second electrical network 22 covers equipment located on the left half of the aircraft; if the turbomachine 1 is located on the right wing of the aircraft, the second network covers equipment located on the right half of the aircraft.

[0037] The second electrical network 22 comprises equipment classified into different categories: so-called “essential” equipment (or circuits), and so-called “non-essential” equipment (or circuits). These categories are typically defined by official organizations (EASA, FAA, etc.).

[0038] Essential equipment includes equipment for all technical loads of the aircraft, cabin emergency lighting and oxygen mask control devices for passengers.

[0039] Non-essential equipment is equipment for commercial and cabin loads.

[0040] The second electrical network 22 comprises in particular equipment that consumes or even very much consumes electrical energy, such as: an air conditioning system for the interior of the aircraft, a defrosting system for the aircraft, electrical kitchen equipment, such as an electric oven, at least one display screen for passengers, allowing them to view videos during a flight of the aircraft.

[0041] The aircraft further comprises an electrical power supply system 24. As its name indicates, the main function of this system 24 is to supply the aforementioned electrical networks 20, 22 with electrical energy, based on the mechanical energy generated by the turbomachine 1 previously described.

[0042] The system 24 comprises a first generation system 26 configured to convert mechanical energy supplied by the turbomachine 1 into first electrical energy.

[0043] The generation system 26 comprises a generator mounted on the high pressure body 6 of the turbomachine 1. More precisely, the generator is an alternator comprising a rotor fixed to the high pressure shaft, and a stator fixed relative to the casing 2 of the turbomachine 1.

[0044] The generator 26 is configured to deliver a first voltage. The first voltage ranges, for example, from 16 Volts to 230 Volts. This first voltage is, for example, an alternating voltage.

[0045] The generator 26 may be a motor-generator, that is to say an electric machine capable of operating not only as a generator but also as an electric motor configured to drive the high-pressure body 6 in rotation using electrical energy. In this respect, the motor-generator 26 in engine mode may be used as a starter when starting the turbomachine 1.

[0046] The system 24 further comprises a first electrical connection adapted to transmit the first electrical energy to the first electrical network 20.

[0047] The first connection comprises in particular a first converter 28 configured to convert the voltage delivered by the generator 26 into a voltage suitable for the first electrical network 20. The converter can provide a rectifier and / or inverter function.

[0048] The output voltage of the first converter 28 (to the first electrical network 20) ​​is for example 540 Volts.

[0049] When the motor-generator 26 operates in engine mode, the rectifier-inverter 28 can convert electrical energy supplied by an auxiliary generator of the aircraft designated APU generator or by low voltage batteries, in order to power the motor-generator 26.

[0050] The system 24 further comprises a second generation system 30 configured to convert mechanical energy supplied by the turbomachine 1 into a second electrical energy, distinct from the first electrical energy.

[0051] The second generation system 30 is distinct from the generator 26. It will even be seen later that the generator 26 and the second generation system 30 are galvanically isolated from each other.

[0052] The second generation system 30 is configured to deliver a second voltage greater than or equal to the first voltage (delivered by the generator 26). The second voltage ranges, for example, from 28 Volts to 1500 Volts. This second voltage may be a direct voltage.

[0053] Generally, the motor-generator 26 is low voltage while the second generation system 30 is high voltage, in the sense that the electrical voltage delivered by the second generation system 30 is higher than the electrical voltage delivered by the first motor-generator 26. Alternatively, the motor-generator 26 and the second generation system 30 can operate at the same voltage.

[0054] The second generation system 30 comprises at least one generator, for example several generators which each contribute to generating the second electrical energy. In the embodiment shown in [Fig.2], the second generation system 30 comprises a generator 32 mounted on the low pressure body 4 of the turbomachine 1, and a generator 34 mounted on the high pressure body 6 of the turbomachine 1.

[0055] The generators 32, 34 may have a rotor and stator-based structure like the generator 26. In this way, the second generation system 30 draws mechanical energy from the rotation of the low-pressure body 4 and / or from the rotation of the high-pressure body 6 to convert them into the aforementioned second electrical energy.

[0056] Each of the two generators 32, 34 may be a motor-generator. In particular, the generator 34 may be a motor-generator capable of operating as an electric motor configured to drive the high-pressure body 6 in rotation using electrical energy. As such, this motor may be used as a starter when starting the turbomachine 1.

[0057] The system 24 further comprises a second electrical connection adapted to transmit the second electrical energy generated by the second generation system 30 to the second electrical network 22.

[0058] The second connection comprises in particular a second converter 36 configured to convert a voltage generated by the second generation system 30 into a voltage adapted to the second electrical network. The converter can provide a rectifier and / or inverter function.

[0059] The system 24 further comprises a switch 38. The switch 38 comprises a first input, a second input and an output. The first input of the switch 38 is connected to the first link, so that the switch 38 can receive the first electrical energy generated by the generator 26. The second input of the switch 38 is connected to the second link, so that the switch 38 can also receive the second electrical energy generated by the second generation system 30. The output of the switch 38 is connected to the second electrical network 22, but is not connected to the first electrical network 20.

[0060] The switch 38 is configurable in two positions: a first position (shown in [Fig.2]) and a second position (shown in [Fig.3]).

[0061] In the first position, the output of the switch 38 is connected to the first input and is not connected to the second input. The switch 38 can then selectively transmit the first electrical energy generated by the generator 26 to the second electrical network 22.

[0062] In the second position, the output of the switch 38 is connected to the second input and is not connected to the first input. The switch 38 can then selectively transmit the second electrical energy generated by the second generation system 30 to the second electrical network 22.

[0063] The switch 38 is for example a reversing contactor.

[0064] As indicated previously, the first electrical network 20 is galvanically isolated from the second generation system 30. This principle of galvanic isolation is in particular respected by the switch 38, the output of which is in no way connected to the first electrical network 20. In this way, a malfunction at the level of the second generation system 30 does not risk reaching and disrupting the critical functions provided by the first electrical network 20.

[0065] The system 24 further comprises at least one contactor (not shown) arranged between the output of the switch 38 and at least one non-essential equipment of the second electrical network. The contactor is configurable in a closed or connected position allowing electrical energy to be transmitted from the output of the switch 38, and in an open or disconnected position, preventing this transmission.

[0066] The system 24 further comprises a control unit 40 configured to control the positioning of the switch 38 and of each contactor. The control unit is for example a control circuit.

[0067] The control unit 40 is electrically powered by the first electrical network 20.

[0068] The generator 26 makes it possible to limit the power, cost and volume of the second generation system 30 and in particular of the generator 34, especially when it operates at low voltage.

[0069] The system 24 described above can be used in the following manner on board the aircraft.

[0070] In case of normal operation, the control unit 40 positions the switch 38 in the second position (see [Fig.3]). Furthermore, each contactor in its closed position. On the one hand, the generator 26, operating at low voltage, supplies the first electrical network 20, which is critical for the safety of the aircraft. On the other hand, the second generation system 30 operating at high voltage supplies the second electrical network 22, less critical for the safety of the aircraft than the first electrical network 20, but very energy-consuming. All the equipment of the second electrical network 22 is supplied, due to the closed position of each contactor.

[0071] In the event of a failure of the second generation system 30 (due for example to an engine failure or electronic failure), the control unit 40 detects this failure. The detection is for example implemented by means of a voltage sensor measuring an abnormal voltage at the generator system. Upon detection of such a failure, the control unit 40 positions the switch 38 in the first position (see [Fig. 2]). The generator 26, operating at low voltage, then supplies not only the first electrical network 20, which is critical for the safety of the aircraft, but also the second electrical network 22. In addition, the control unit 40 can position the or each aforementioned contactor in its open position, so as to interrupt the power supply to certain equipment of the second electrical network 22 which is not essential and yet consumes electrical energy.Due to the low power available from generator 26, it is preferable to concentrate the power supply to the loads necessary for the continuation of the aircraft flight. The following non-essential equipment can thus be deactivated: the fans of the air conditioning system, the kitchen ovens, the passenger display screens, a cabin satellite connection system. Furthermore, cabin lighting is preferably reduced to a minimum.

[0072] The electrical power supply system 24 described above in relation to the appended figures may be the subject of other variant embodiments.

[0073] In particular, the second generation system 30 can also supply a third electrical network comprising a hybrid propulsion system of the aircraft, which would be different from the electrical networks 20 and 22.

[0074] Furthermore, the generation system 26 as illustrated comprises only one generator. Alternatively, this generation system 26 could comprise several generators.

[0075] The electrical power supply systems described above find advantageous application within a hybrid propulsion aircraft. A hybrid propulsion aircraft comprises a conventional propulsion system (turbomachine), which is completed by an electric motor.

Claims

Claims

1. An electrical power system (24) for an aircraft, the electrical power system (24) comprising: - a first generation system (26) configured to convert a first mechanical energy supplied by a turbomachine (1) into a first electrical energy, - a first electrical connection adapted to transmit the first electrical energy to a first electrical network (20) for the aircraft, the first electrical network (20) being or comprising an emergency network which is critical for the safety of the aircraft, - a second generation system (30) configured to convert a second mechanical energy supplied by the turbomachine (1) into a second electrical energy, - a switch (38) configurable in: i) a first position in which the switch (38) selectively transmits the first electrical energy to a second electrical network (22) for the aircraft distinct from the first electrical network (20),and ii) a second position in which the switch (38) selectively transmits the second electrical energy to the second electrical network (22), wherein the switch galvanically isolates the second generation system (30) from the first electrical network (20), in particular in the first position and in the second position, wherein the second generation system (30) is further configured to supply power to a third electrical network comprising a hybrid propulsion system of the aircraft, the third electrical network being different from the first electrical network (20) and the second electrical network (22).,

2. The power supply system (24) of claim 1, wherein the first generating system (26) is at a first voltage and the second generating system (30) is at a second voltage greater than or equal to the first voltage.

3. Electrical power supply system (24) according to one of the preceding claims, in which the first generation system (26) is suitable for being mounted on a high pressure body (6) of the turbomachine (1).

4. An electrical power supply system (24) according to one of the preceding claims, wherein the second generation system (30) comprises a generator (32) suitable for being mounted on a low pressure body (4) of the turbomachine (1).

5. Electrical power supply system (24) according to one of the preceding claims, in which the second generation system (30) comprises a generator (34) suitable for being mounted on a high pressure body (6) of the turbomachine (1).

6. Electrical power supply system (24) according to one of claims 1 to 3, in which the second generation system (30) comprises two generators (32, 34) including a generator (32) suitable for being mounted on a low pressure body (4) of the turbomachine (1) and a generator (34) suitable for being mounted on a high pressure body (6) of the turbomachine (1), the two generators (32, 34) being interconnected so as to each contribute to generating the second electrical energy.

7. Electrical power system (24) according to one of the preceding claims, wherein the first electrical network (20) comprises at least one of the following equipment: a fly-by-wire control for the aircraft, a navigation system for the aircraft, a communication system for the aircraft.

8. Electrical power system (24) according to one of the preceding claims, wherein the second electrical network (20) comprises at least one of the following equipment: an air conditioning system for the interior of the aircraft, a de-icing system for the aircraft.

9. An electrical power supply system (24) according to one of the preceding claims, comprising a control unit (40) configured to switch the switch (38) from the second position to the first position upon detection of a failure of the second generation system (30), the control unit being electrically powered by the first electrical network (20).

10. Aircraft, preferably with hybrid propulsion, comprising: - a turbomachine (1), - a first electrical network (20) being or comprising an emergency network ensuring a critical function for the safety of the aircraft, - a second electrical network (22) separate from the first electrical network, - a system (24) according to one of claims 1 to 9 for electrically supplying the first electrical network (20) and the second electrical network (22) from the turbomachine (1).

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