Hybrid electrical architecture for aircraft

Abstract

The invention relates to a hybrid electrical architecture (101) for an aircraft (103), the architecture comprising: a turbine (107) and a reduction gearbox (111) intended to rotate at least one propulsion member (105) of the aircraft (103). The architecture (101) further comprises at least one low-voltage electrical network (113) having at least one low-voltage motor (117, 118) mounted on the reduction gearbox (111) or the turbine (107), and a high-voltage electrical network (125) having a high-voltage motor (129) mounted on the turbine (107).

Description

Technical Field

[0001] The present invention relates to the field of so-called hybrid propulsion aircraft, ie aircraft that combine two different kinds of propulsion sources, for example thermal and electrical. The present invention relates in particular to an aircraft hybrid electrical architecture. Background Art

[0002] Document FR-A1-2962 404 describes a hybrid electrical architecture in which the auxiliary electrical network can be disconnected.

[0003] The architecture described in this document is a so-called parallel hybrid electrical architecture in which, on the one hand, two high-voltage electric machines are mounted on the main gearbox and operate in a reversible manner, i.e. they are able both to provide torque to one or more rotors through the main power gearbox and to extract torque from one or more shafts through the main power gearbox to generate electrical energy. On the other hand, a so-called low-voltage electric machine (operating at 28 volts, for example) is driven by the high-voltage body of the aircraft's turbine to operate as a generator (generating electrical energy) or as a motor to start the turbine.

[0004] While this architecture theoretically allows power to be transferred between the low voltage motor and the high voltage motor, it does have a number of disadvantages.

[0005] Firstly, when the turbine is started, the low voltage electric machine can only be operated in motor mode. The low voltage electric machine cannot continuously mechanically assist the high pressure body of the turbine (by providing torque) above 80% N1. The design of the electric machine and the accessory gearbox (or accessory gearbox, AGB) means that it is not possible to provide motor torque to drive the high pressure body above about 50-60% N1. This is particularly due to the current technology of electric machines used as starter / generators and the fact that such a need has not yet been identified.

[0006] Furthermore, low voltage operation rapidly induces high currents to transmit significant power (on the order of tens of kilowatts), which implies the use of electrical conductors with large cross-sections, resulting in increased mass.

[0007] Furthermore, the transmission of power from the low-voltage motor to the high-voltage motor is carried out via two different network voltages, which requires the use of a converter, thus significantly reducing the efficiency of this power transmission. In addition, this creates a common point between the low-voltage network and the high-voltage network, increasing the risk of fault propagation between the two networks.

[0008] Finally, the weight burden associated with using high voltage batteries in this architecture may be prohibitive for aerial work missions. Summary of the invention

[0009] The present invention proposes a solution to these disadvantages.

[0010] In particular, the purpose of the present invention is to enable, on the one hand, the transmission of power between the high-voltage body and the low-voltage body of an aircraft or between the high-voltage body and the main power gearbox of an aircraft using only the high-voltage network (also called the internal hybrid electrical network) (i.e. without calling the low-voltage electrical network used to supply power to aircraft equipment) in two possible transmission directions, and on the other hand, to isolate the internal hybrid electrical network (i.e. the propulsion electrical network) from the electrical network configured to supply power to aircraft equipment (i.e. the non-propulsion electrical network). In other words, the non-propulsion electrical network and the propulsion electrical network are separated.

[0011] To this end, a first aspect of the invention relates to a hybrid electrical architecture for an aircraft, the architecture comprising a turbine and a reduction gear intended to drive in rotation at least one propulsion member of the aircraft,

[0012] The architecture also includes:

[0013] a low-voltage electrical network comprising a low-voltage electrical energy storage device and at least one low-voltage electric machine, both of which are electrically connected to a first electrical bus, the first electrical bus being intended to provide electrical energy to loads on board the aircraft; and

[0014] a high-voltage electrical network comprising two high-voltage electric machines electrically connected to a second electrical bus electrically connected to the first electrical bus via an electrical converter of the high-voltage electrical network and a first contactor of the low-voltage electrical network;

[0015] The architecture is characterized by:

[0016] Two high-voltage motors are mounted on the turbine and each high-voltage motor is mechanically coupled to the shaft of the turbine.

[0017] At least one low-voltage electric machine is mounted on the reduction gear or on the turbine and is mechanically coupled to the reduction gear or to the shaft of the turbine.

[0018] In one embodiment, the first high-pressure motor is mounted on the low-pressure body of the turbine and is mechanically connected to the shaft of the low-pressure body; the second high-pressure motor is mounted on the high-pressure body of the turbine and is mechanically connected to the shaft of the high-pressure body; and the first low-pressure motor is mechanically connected to the reduction gear.

[0019] In another embodiment, the high voltage network further comprises a high voltage electrical energy storage device, which is preferably connected to the second electrical bus via an electrical protection device.

[0020] According to another embodiment, the first high-pressure motor is mounted on the low-pressure body of the turbine and is mechanically connected to the shaft of the low-pressure body; the second high-pressure motor is mounted on the high-pressure body of the turbine and is mechanically connected to the shaft of the high-pressure body; and the first low-pressure motor is also mounted on the high-pressure body of the turbine and is mechanically connected to the shaft of the high-pressure body.

[0021] In another embodiment, the second high-voltage motor and the first low-voltage motor are independent windings of a dual-winding motor, respectively, and the independent windings are isolated from each other by electrical insulation.

[0022] In another embodiment, the second low-pressure electric machine is mounted on the low-pressure body of the turbine and is coupled to the shaft of the low-pressure body.

[0023] In another embodiment, the first high-voltage motor and the second low-voltage motor are independent windings of a dual-winding motor, respectively, and the independent windings are isolated from each other by electrical insulation.

[0024] According to another embodiment, the first low-pressure motor and the second low-pressure motor are mechanically connected to the motion output end of the high-pressure body of the turbine and the motion output end of the low-pressure body of the turbine, respectively, and these motion output ends are different from the motion output ends of the high-pressure body and the low-pressure body, which are respectively connected to the first high-pressure motor and the second high-pressure motor.

[0025] In another embodiment, the high voltage motor is electrically connected to the second electrical bus via a second contactor, and the at least one low voltage motor is electrically connected to the first electrical bus via at least one third contactor.

[0026] Furthermore, according to a second aspect the present invention also relates to an aircraft comprising: a turbine configured to drive a propulsion member in rotation, and a hybrid electrical architecture according to any one of the preceding claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention will be better understood and other details, features and advantages of the invention will become more apparent from the following description given by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0028] Figure 1 is a schematic diagram of an aircraft including a hybrid electrical architecture according to a first embodiment of the present invention.

[0029] Figure 2 is a schematic diagram of an aircraft including a hybrid electrical architecture according to a second embodiment of the present invention.

[0030] Figure 3 is a schematic diagram of an aircraft including a hybrid electrical architecture according to a third embodiment of the present invention.

[0031] Figure 4is a schematic diagram of an aircraft including a hybrid electrical architecture according to a fourth embodiment of the present invention.

[0032] Figure 5 is a schematic diagram of an aircraft including a hybrid electrical architecture according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0033] refer to Figure 1 , a first embodiment of a hybrid electrical architecture 101 of an aircraft 103 according to the present invention will now be described.

[0034] exist Figure 1 In the example shown in the following figures, the mechanical power is transferred between the various elements of the architecture by three parallel lines, while the electrical power is transferred between the various elements of the architecture by a single line.

[0035] In the non-limiting example shown, the aircraft 103 is a rotorcraft, such as a helicopter. In this case, the rotor (not shown) is driven to rotate by a propulsion member 105 of the aircraft 103.

[0036] More specifically, the architecture 101 includes a turbine 107, which is mechanically coupled to a reduction gear 111, in this case a main power gearbox 111, by means of an overrunning clutch 109, which is configured to drive a propulsion member 105 (in this case a rotor mast, hereinafter referred to as a rotor) of the aircraft 103 in rotation. Thus, during operation, the turbine 107 rotates the main power gearbox 111, which in turn rotates the rotor 105.

[0037] A person skilled in the art will understand that the invention is also applicable to aircraft using at least one propulsion assembly of the electric hybrid turboprop type having as its propulsion member a pusher propeller and in which the reduction gear is a "power gearbox".

[0038] In addition, the main power gearbox 111 may also be configured to rotate other rotors (not shown), such as an anti-torque rotor (also referred to as a tail rotor).

[0039] The architecture 101 also includes a low voltage electrical network 113, which includes a low voltage electrical energy storage device 115 (such as a battery) and at least one low voltage motor 117. Here and hereinafter, the term "low voltage" refers to a voltage less than 50 volts, for example 28 volts. Those skilled in the art will also understand that in this architecture, the low voltage motor 117 may be optional, particularly when it is used for light helicopters and more particularly non-IFR light helicopters (i.e., not intended for instrument flight).

[0040] The low voltage electric machine 117 and the low voltage electrical energy storage device 115 are both electrically connected to an electrical bus 119 that is designed to provide electrical energy to loads 121 on the aircraft 103 .

[0041] By way of example, the low-voltage electric machine 117 (which provides, for example, less than 9 kW of electrical power) and the low-voltage electrical energy storage device 115 deliver a voltage of 28 volts, so that the low-voltage electrical network has a nominal voltage equal to 28 volts.

[0042] exist Figure 1 In the non-limiting example shown, the electrical bus 119 is divided into two parts 119a and 119b, which are connected together by a contactor 123, which enables the two parts 119a and 119b of the electrical bus 119 to be electrically connected or disconnected and thus isolate the part of the bus supplied by the low-voltage electrical network 113 (i.e., part 119a) from the part of the bus supplied by the high-voltage electrical network 125, which will be described in more detail below.

[0043] Furthermore, in this configuration, the loads 121 may be divided into two groups of loads 121a and 121b, which may be powered by the portion 119a and / or the portion 119b of the electrical bus 119, so that an “emergency” power supply may be provided to each load 121. The two groups of loads 121a and 121b may be, for example, equipment that is considered critical to the operation of the aircraft 103 and equipment that is considered auxiliary to the operation of the aircraft 103, respectively.

[0044] In the non-limiting example described herein, the low-voltage electrical network 113 also includes an apron socket 127, which can be connected to an apron unit (i.e., a generator, forming part of the ground infrastructure), and the aircraft can be connected to the apron socket when parked so that the apron socket supplies electrical energy to the aircraft, and the apron socket 127 supplies electrical power (at a voltage of 28V).

[0045] As described above, the architecture 101 also includes a high-voltage electrical network 125, which includes two high-voltage motors 129 electrically connected to an electrical bus 131. The electrical bus 131 is electrically connected to the electrical bus 119 via an electrical converter 133 included in the high-voltage electrical network 125. Here and in the following, the term "high voltage" refers to a voltage greater than 50 volts. As non-limiting examples, the voltage level used can be 115 volts of alternating current (AC) or 270 volts, 540 volts, or 800 volts of direct current (DC). In addition, there is no upper limit to the voltage value corresponding to "high voltage".

[0046] The electrical converter 133 may be, for example, a DC / DC converter or an AC / DC converter, the function of which in each case is to adapt the voltage of the high-voltage electrical network 125 to the voltage of the low-voltage electrical network 113 .

[0047] Furthermore, the electrical converter 133 is connected to the electrical bus 119 of the low-voltage electrical network 113 via a contactor 135 , which comprises the contactor 135 .

[0048] The high voltage electrical network 125 further comprises an Electrical Power Control Unit 137 , also referred to by the acronym EPCU, which is electrically connected to the high voltage motor 129 and is configured to regulate the voltage delivered by the high voltage motor 129 and enable the voltage to be controlled.

[0049] exist Figure 1 In the example shown, two high-voltage motors 129 are mounted on the turbine 107 and are mechanically coupled to the shaft (not shown) of the turbine 107. The fact that two high-voltage motors 129 are mounted on the turbine 107 means that there are at least two mechanical inputs on the turbine 107 to connect both the high-pressure body and the low-pressure body to the motor 129. In addition, there are at least two rotating power outputs and at least two fixed interfaces, at least two rotating power outputs are respectively connected to the rotor shaft of each motor 129, each rotating power output is capable of transmitting the power provided or output by the motor, and at least two fixed interfaces are used to fix the static housing of the motor 129 to the turbine 107.

[0050] Furthermore, the mechanical coupling discussed means that the electric machine can either receive torque or provide torque to the shaft of the turbine to which it is coupled, depending on whether the turbine is operating as a generator or a generator.

[0051] More specifically, in Figure 1 In the configuration shown, one of the two high-voltage motors 129 is mounted on the low-pressure body 139 of the turbine 107 and is therefore mechanically coupled to the shaft of the low-pressure body 139. The other high-voltage motor 129 is mounted on the high-pressure body 141 of the turbine 107 and is therefore mechanically coupled to the shaft of the high-pressure body 141. As a result, the high-voltage motor 129 mechanically coupled to the shaft of the high-pressure body 141 is able to start the turbine 107.

[0052] The two high-voltage motors 129 are reversible, that is, they can drive the turbine 107 or extract mechanical power from the turbine 107 to generate electrical energy. Therefore, mechanical power can be transferred from the high-voltage body 141 to the low-voltage body 139 via the high-voltage motors 129, and vice versa. In addition, in order to achieve this reversibility, the two EPCUs 137 are also designed to be reversible, because the electrical energy generated by any of the high-voltage motors 129 must be able to be transferred through the EPCU 137 via the electrical bus 131 that electrically connects the two high-voltage motors.

[0053] Furthermore, the low voltage motor 117 is mechanically coupled to the main power gearbox 111. In this configuration, the low voltage motor 117 functions only as a generator.

[0054] Finally, in addition to the contactors already mentioned above, the high-voltage motor 129 is electrically connected to the electrical bus 131 via a contactor 143, which, if necessary, is able to protect the two high-voltage motors separately in the event of an electrical fault on the electrical bus 131, or to prevent the electrical fault from propagating from one motor 129 to the other motor 129. The low-voltage motor 117 is also electrically connected to the electrical bus 119 via a contactor 145.

[0055] Figure 2 Another embodiment of the hybrid electrical architecture 101 is shown, in which, in addition to the already mentioned Figure 1 In addition to all the elements described, the high-voltage network 125 also includes a high-voltage electrical energy storage device 147 connected to the electrical bus 131. In addition, in the non-limiting example shown, the high-voltage electrical energy storage device 147 is connected to the electrical bus 131 via an electrical protection device 149. The electrical protection device 149 is capable of electrically isolating the energy storage device in the event of electrical damage to the network or the storage device itself. The electrical protection device can be an electromagnetic contactor, a static contactor, or a combined device, such as an ignition contactor or an ignition fuse.

[0056] Advantageously, high voltage electrical energy storage device 147 may be used to stabilize electrical bus 131 and / or provide an additional source of hybrid power when needed.

[0057] Figure 3Another embodiment of the hybrid electrical architecture 101 is also shown, in which a high-voltage motor 129 is mounted on a low-voltage body 139 and mechanically coupled to the shaft of the low-voltage body 139, another high-voltage motor 129 is mounted on a high-voltage body 141 and mechanically coupled to the shaft of the high-voltage body 141, and the low-voltage motor 118 is also mounted on the high-voltage body 141 and mechanically coupled to the shaft of the high-voltage body 141. In this case, the low-voltage motor 118 can also be used as a starter for the high-voltage body 141 of the turbine 107. In addition, those skilled in the art will understand that in this configuration, the converter 133 is optional.

[0058] In addition, Figure 3 In the configuration shown, the high voltage motor 129 and the low voltage motor 118 mounted on the high voltage body 141 are actually independent windings of a dual winding motor 151. These independent windings are isolated from each other by electrical insulation to ensure isolation between the two electrical networks.

[0059] Figure 4 Shows the use of Figure 3 Another embodiment of the configuration of the embodiment shown in , but with the addition of a second low-pressure motor 117, which is mounted on the low-pressure body 139 of the turbine 107 and is coupled to the shaft of the low-pressure body 139. In addition, in this configuration, since there are a sufficient number of low-pressure sources, the converter 133 and the contactor 135 are omitted.

[0060] Similarly, as in reference Figure 3 In the case of the described embodiment, the high voltage motor 129 and the low voltage motor 117 mounted on the low voltage body 139 are actually separate windings of a two-winding motor 151. These separate windings are also isolated from each other by electrical insulation.

[0061] at last, Figure 5 A final embodiment is shown in which the low-voltage electrical network 113 comprises two low-voltage motors 118 and 117, which are mechanically coupled to the power take-offs of the high-voltage body 141 of the turbine 107 and to the power take-offs of the low-voltage body 139 of the turbine 107, respectively. These power take-offs are separated from the power take-offs of the high-voltage body 141 and the low-voltage body 139, which are coupled to the two high-voltage motors 129, respectively. Furthermore, the low-voltage motor 118 mounted on the high-voltage body 141 can be used as a generator or a starter.

Claims

1. A hybrid electrical architecture (101) for an aircraft (103), the architecture (101) comprising: a turbine (107) and a reduction gear (111) intended to drive in rotation at least one propulsion member (105) of the aircraft (103), The architecture (101) further comprises: a low-voltage electrical network (113), comprising a low-voltage electrical energy storage device (115) and at least one low-voltage electric machine (117, 118), the low-voltage electrical energy storage device and the at least one low-voltage electric machine being electrically connected to a first electrical bus (119) intended to provide electrical energy to a load (121) on the aircraft (103); and A high-voltage electrical network (125), the high-voltage electrical network comprising two high-voltage motors (129), the two high-voltage motors being electrically connected to a second electrical bus (131), the second electrical bus (131) being electrically connected to the first electrical bus (119) via an electrical converter (133) of the high-voltage electrical network (125) and a first contactor (135) of the low-voltage electrical network (113), The architecture (101) is characterized in that: The two high-voltage motors (129) are mounted on the turbine (107), and each high-voltage motor is mechanically coupled to a shaft (139, 141) of the turbine (107), and The at least one low-voltage motor (117, 118) is mounted on the reduction gear (111) or on the turbine (107) and is mechanically coupled to the reduction gear (111) or to a shaft of the turbine (107).

2. The architecture (101) according to claim 1, wherein: The first high-pressure motor (129) is mounted on the low-pressure body (139) of the turbine (107) and is mechanically connected to the shaft of the low-pressure body (139); the second high-pressure motor (129) is mounted on the high-pressure body (141) of the turbine (107) and is mechanically connected to the shaft of the high-pressure body (141); and the first low-pressure motor (117) is mechanically connected to the reduction gear (111).

3. The architecture (101) according to claim 2, wherein: The high voltage network (125) further comprises a high voltage electrical energy storage device (147), which is preferably connected to the second electrical bus (131) via an electrical protection device (149).

4. The architecture (101) of claim 1, wherein: The first high-pressure motor (129) is mounted on the low-pressure body (139) of the turbine (107) and is mechanically connected to the shaft of the low-pressure body (139); the second high-pressure motor (129) is mounted on the high-pressure body (141) of the turbine (107) and is mechanically connected to the shaft of the high-pressure body (141); and the first low-pressure motor (118) is also mounted on the high-pressure body (141) of the turbine (107) and is mechanically connected to the shaft of the high-pressure body (141).

5. The architecture (101) according to claim 4, wherein: The second high-voltage motor (129) and the first low-voltage motor (118) are respectively independent windings of a double-winding motor (151), and these independent windings are isolated from each other by electrical insulation.

6. Architecture (101) according to claim 4 or 5, wherein: The second low-pressure motor (117) is mounted on the low-pressure body (139) of the turbine (107) and is coupled to the shaft of the low-pressure body (139).

7. The architecture (101) according to claim 6, wherein: The first high-voltage motor (129) and the second low-voltage motor (117) are respectively independent windings of a double-winding motor (151), and these independent windings are isolated from each other by electrical insulation.

8. The architecture (101) of claim 6, wherein: The first low-pressure motor (118) and the second low-pressure motor (117) are respectively mechanically connected to the motion output end of the high-pressure body (141) of the turbine (107) and the motion output end of the low-pressure body (139) of the turbine (107), and the motion output ends are different from the motion output ends of the high-pressure body (141) and the low-pressure body (139), which are respectively connected to the first high-pressure motor (129) and the second high-pressure motor (129).

9. The architecture (101) according to any one of the preceding claims, wherein: The high voltage motor (129) is electrically connected to the second electrical bus (131) via a second contactor (143), and the at least one low voltage motor (118) is electrically connected to the first electrical bus (119) via at least one third contactor (145).

10. An aircraft (103) comprising a turbine (107) configured to drive a propulsion member (105) in rotation and a hybrid electrical architecture (101) according to any one of the preceding claims.

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