Electric aircraft propulsion system

Abstract

The invention relates to an electric aircraft propulsion system (100) comprising: - an electric machine (110) configured to operate as a motor or generator and comprising a rotor; - a DC voltage source; - a power electronic device (120) connected to the DC voltage source and to the electric machine; and - a cooling device (172, 173) for cooling the electric machine and the power electronic device by heat-transfer fluid, the power electronic device comprising at least two interchangeable power electronic modules (121, 122, 123, 124) which are configured to each form an electrical path from the DC voltage source to the electric machine, each module comprising at least one first ready-to-use connector configured to be connected to the electric machine and to transmit an electrical signal, a second ready-to-use connector (151, 154) configured to be connected to the electric machine and to transmit electrical power, and a third ready-to-use connector configured to connect the cooling device to the electric machine, and in that the electrical propulsion system comprises a receiving structure (130) attached to the electric machine on which the power electronic modules are placed and delimiting an empty area (135) around the axis of the rotor of the electric machine.

Description

[0001] Description

[0002] Title of the invention: Electric aircraft propulsion system

[0003] Technical Field

[0004] The present invention relates to the general field of aircraft electric propulsion systems, and more particularly to the mechatronic integration of a power electronics device of an electric propulsion system.

[0005] Electric or hybrid electric / thermal propulsion of conventional aircraft (CTOL), short takeoff and landing (STOL) and vertical takeoff and landing (VTOL) aircraft is achieved by one or more electric machines. The conventional control architecture of the electric machine consists of a DC voltage source connected by power harnesses to a power electronics and control device, itself connected by power harnesses to an electric machine, itself connected to a propeller via a rotor, a gearbox or any other transmission means.

[0006] In this conventional architecture, the elements are integrated separately according to their function, but they have a fairly high mass and overall size, particularly for high powers (greater than 200 kW).

[0007] In addition, the power harnesses used have large diameters due to the strong currents passing through them to reduce thermal losses.

[0008] Furthermore, the power electronics elements are usually parallelepiped in shape and do not lend themselves easily to integration in the nacelle area.

[0009] Thus, the conventional architectures of these power electronics are not suitable for integration directly on the rotating machines and in the nacelle area; require sets of electrical harnesses which take up space and generate thermal losses; have a significant mass and size making their access and maintenance complex, particularly when it is necessary to separate and / or duplicate the electrical paths to ensure availability and operational safety to cover certification requirements.

[0010] It is therefore desirable to have a new power electronics architecture for an electric machine capable of better integration into a nacelle area, being less bulky, of reduced mass while supporting high powers.

[0011] Statement of the invention

[0012] The invention relates to an electric aircraft propulsion system comprising:

[0013] - an electrical machine configured to operate as a motor or generator and comprising a rotor,

[0014] - a direct voltage source,

[0015] - a power electronics device connected to the direct voltage source and to the electrical machine, and

[0016] - a device for cooling the electrical machine and the power electronics device using a heat transfer fluid, characterized in that the power electronics device comprises at least two interchangeable power electronics modules each configured to form an electrical path from the DC voltage source to the electrical machine, each module comprising at least a first ready-to-use connector configured to be connected to the electrical machine and transmit an electrical signal, a second ready-to-use connector configured to be connected to the electrical machine and transmit electrical power, and a third ready-to-use connector configured to connect the cooling device to the electrical machine,and in that the electric propulsion system comprises a receiving structure attached to the electric machine on which the power electronics modules are placed and delimiting an empty zone around the axis of the rotor of the electric machine. The power electronics modules are thus removable and therefore replaceable online, on the aircraft.,

[0017] The presence of several interchangeable power electronics modules allows for a modular electric propulsion system whose modules are easily replaceable and interchangeable and improves the availability of the power chain, since the electrical tracks formed by the modules are redundant with each other. Maintenance of the modules is also facilitated, since the modules are easily removable and / or interchangeable.

[0018] Being small in size compared to power electronics devices, the modules allow for better management of environmental constraints such as vibrations, because the number of fixings is reduced, or humidity, because there will be less condensation in small volumes.

[0019] In addition, the plug-and-play connectors allow for a one-step "blind" mounting of the power electronics modules to the cooling device and the electrical machine, by directly connecting the modules to the cooling device and the electrical machine. They also eliminate the need for a separate cable between the power electronics modules and the electrical machine. This eliminates the need for power harnesses between the two.

[0020] In particular, the first ready-to-use connector allows the transmission of electrical signals of low voltage and current levels, originating, for example, from sensors present in the aircraft, for example in the electrical machine, between the electrical machine and the power electronics modules.

[0021] The second ready-to-use connector allows electrical power to be transmitted between the electrical machine and the power electronics modules, i.e. transmitting a power supply.

[0022] The third ready-to-use connector is a hydraulic connector, as it allows the passage of the heat transfer fluid of the cooling device between the power electronics modules and the electric machine. It thus connects the electric machine to the cooling device. Depending on a particular feature of the system, at least two power electronics modules may be identical.

[0023] It is also easier to adapt to the space allocated to the power electronics device thanks to the modules which will be smaller than a single classic power electronics block.

[0024] Thanks to the modules' ready-to-use connectors, the power harness between the power electronics and the electric machine can be eliminated. This reduces the overall size of the propulsion system and also reduces its weight.

[0025] Finally, the proximity between the modules and the electric machine allows the use of a single cooling device for the electric machine and the power electronics device, which reduces the overall mass and volume of the electric propulsion system.

[0026] In addition, the host structure can be a separate structure made of one or more parts or be part of the electric machine. It makes it easier to mount the power electronics modules on the electric machine and takes up some of the stress.

[0027] For example, it is a stainless steel sheet structure formed of two pieces assembled together and fixed to the electric machine.

[0028] According to a particular characteristic of the invention, at least one of the ready-to-use connectors is placed on one face of the power electronics modules opposite the electrical machine.

[0029] In other words, at least one of the faces of the power electronics modules facing the electric machine supports ready-to-use connectors, such as blind plug-in connectors, in the rear face of the electric machine.

[0030] This allows for connections between the electrical machine and the power electronics modules to be completely blind. According to another particular feature of the invention, at least one of the ready-to-use connectors is placed on a side face of the power electronics modules.

[0031] In other words, at least one of the ready-to-use connectors is placed on a face, accessible for assembly, of the power electronics modules.

[0032] According to another particular characteristic of the invention, the receiving structure comprises positioning guides ensuring automatic mutual alignment between the ready-to-use connectors of the power electronics modules and the electrical machine.

[0033] These positioning guides facilitate the mounting of the modules on the electrical machine by aligning the modules and their ready-to-use connectors facing the electrical machine (and its own connectors dedicated to electrical power, electrical signals and circulation of the heat transfer fluid of the cooling device).

[0034] According to another particular characteristic of the invention, the electric propulsion system comprises fixing means placed on the power electronics modules configured to assemble the power electronics modules to the host structure and / or assemble the power electronics modules to the electric machine and / or assemble the power electronics modules together.

[0035] These fixing means hold the modules in position on the electric machine and stiffen the entire electric propulsion system.

[0036] According to a particular characteristic of the invention, the power electronic modules have a power of between 100 kW and 300 kW, for example 200 kW.

[0037] According to another particular characteristic of the invention, the electric machine is a permanent magnet motor.

[0038] According to another particular characteristic of the invention, the electric propulsion system comprises a propeller pitch actuator placed in the empty zone in the axis of the rotor. In this case, the actuator can be attached to the host structure of the power electronics device in order to fix it. The actuator can also be controlled by the power electronics device or by another external control member.

[0039] According to one embodiment of the invention, the system is a vertical takeoff and landing (VTOL) aircraft propulsion system.

[0040] According to another embodiment of the invention, the system is a short takeoff and landing (STOL) aircraft propulsion system.

[0041] According to another embodiment of the invention, the system is a conventional aircraft propulsion system (CTOL).

[0042] Another subject of the invention is an aircraft with electric or hybrid electric / thermal propulsion comprising a propulsion system according to the invention.

[0043] Brief description of the drawings

[0044] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not limiting in nature.

[0045] [Fig. 1] Figure 1 represents, schematically and partially, an electric propulsion system according to one embodiment of the invention.

[0046] [Fig. 2] Figure 2 shows, schematically and partially, ready-to-use connectors present on the power electronics modules of the electric propulsion system according to one embodiment of the invention.

[0047] [Fig. 3] Figure 3 shows, schematically and partially, positioning guides present on the power electronics modules of the electric propulsion system according to one embodiment of the invention.

[0048] [Fig. 4] Figure 4 shows, schematically and partially, ready-to-use connectors present on the power electronics modules of the electric propulsion system according to another embodiment of the invention. [Fig. 5] Figure 5 shows, schematically and partially, means for fixing the power electronics modules to each other and to the electric machine of the electric propulsion system according to an embodiment of the invention.

[0049] Description of the embodiments

[0050] In the description, the term "power electronics" also means "power and control electronics".

[0051] Figure 1 schematically and partially represents an electric propulsion system 100 according to one embodiment of the invention.

[0052] The electric propulsion system 100 comprises an electric machine 110, configured to operate as a motor or generator, a power electronics device 120, a direct voltage source connected to the power electronics device 120 and a heat transfer fluid cooling device 172, 173 of the power electronics device 120 and the electric machine 110.

[0053] The electrical machine 110 comprises a rotor that may or may not be hollow, and the power electronics device 120 comprises four power electronics modules 121, 122, 123 and 124. The modules 121, 122, 123 and 124 are interchangeable. That is to say, each of the electronics modules comprises an interface capable of being placed on each of the external surfaces of the host structure 130. In other words, the power electronics modules may comprise interfaces compatible with the host structure from the point of view of electrical connections and mechanical characteristics (by way of non-exhaustive examples, the connectors, the attachment zones, the allocated volume, etc.). They have functionalities and performances that make it possible to meet the desired needs and performances.

[0054] According to a particular characteristic of the system, at least two power electronics modules may be identical. They each provide electrical energy for an electrical path from the DC voltage source to the electric machine 110, and therefore form four independent electrical paths. These modules 121, 122, 123 and 124 thus allow segregation of the electrical paths and redundancy. This makes it possible to increase the overall availability of the electric propulsion system 100. The propulsion system 100 may further comprise one inverter per electrical path (therefore in this example, four inverters) connected to a power electronics module and making it possible to provide, each, a quarter of the total power to the electric machine 110.

[0055] The electric propulsion system 100 comprises a receiving structure 130 attached to the electric machine 110 on which the four power electronic modules 121, 122, 123 and 124 are placed on the external surfaces of the receiving structure 130. The receiving structure 130 thus delimits an empty zone 135 around the axis of the rotor of the electric machine 110. This empty zone can, for example, accommodate a system for actuating the pitch of the blades of a propeller driven by the electric machine 110 or a system for de-icing the blades of the propeller which will be aligned with the axis of the rotor of the machine 110. Thus, it is possible to move the control mechanics of the propellers to the center of the propulsion system 100 and obtain a compact system.

[0056] The power electronics device 120 is therefore placed on the rear face of the motor 110, which makes it possible to do without a power harness and electromagnetic filtering between the motor 110 and the power electronics modules 121, 122, 123, 124.

[0057] Since the power electronics modules 121, 122, 123, 124 are placed as close as possible to the electric machine 110, a single cooling device 172, 173 is used to cool the electric machine 110 and the modules 121, 122, 123, 124 of the power electronics device 120. Thus, the heat transfer fluid, which is for example an oil, glycol water or another heat transfer fluid, first cools the modules 121, 122, 123, 124 and then the electric machine 110. The circuits 172 and 173 represent an example of the passage of the heat transfer fluid over the modules 122 and 123. The use of a single common cooling device makes it possible to reduce the total mass of the electric propulsion system 100.

[0058] Each module 121, 122, 123, 124 comprises a first ready-to-use connector configured to be connected to the electrical machine 110 and transmit an electrical signal (references 252 and 292 visible in FIG. 2, reference 392 visible in FIG. 3, and reference 492 visible in FIG. 4), a second ready-to-use connector configured to be connected to the electrical machine 110 and transmit electrical power (connector 154 for the module 124 and connector 151 for the module 121 in FIG. 1, references 282 and 251 visible in FIG. 2, reference 352 in FIG. 3 and reference 452 visible in FIG. 4) and a third ready-to-use connector configured to connect the cooling system to the electrical machine (reference 271 visible in FIG. 2, reference 372 visible in FIG. 3, reference 472 visible in FIG. 4). visible in Figure 4).

[0059] These ready-to-use connectors are described in more detail with reference to Figures 2, 3 and 4.

[0060] The electric propulsion system 100 also comprises positioning guides 142, 143 for ensuring automatic mutual alignment between the ready-to-use connectors of the modules 121, 122, 123, 124 and the electric machine 110. In FIG. 1, only the guides 142, 143 of the modules 122 and 123 are shown.

[0061] These positioning guides 142, 143 are described in more detail with reference to FIG. 3.

[0062] Fastening means 161, 164 are also placed on the modules 121, 122, 123, 124 for assembling the modules to the electrical machine 110, and are described in more detail with reference to FIG. 5.

[0063] Figure 2 shows, schematically and partially, two power electronic modules 221 and 222 as described in Figure 1 and their ready-to-use connectors.

[0064] In Figure 2(a), the power electronics module 222 comprises on its face 222a ready-to-use connectors 282 configured to transmit electrical power to the electric machine, a ready-to-use connector 252 configured to transmit an electrical signal to the electric machine, and a ready-to-use connector 272 configured to connect the cooling device to the electric machine. The connector 272 more particularly makes it possible to circulate the heat transfer fluid to the electric machine after it has cooled the power electronics module 222.

[0065] The face 222a of the module 222 faces the electrical machine. Thus, the ready-to-use connectors 282, 252 and 272 are closest to the electrical machine and form completely blind connections when the module 222 is assembled to the host structure attached to the electrical machine and described previously.

[0066] In Figure 2(b), the power electronics module 221 comprises on its face 221a, facing the electric machine 210, a ready-to-use connector 251 configured to transmit electrical power to the electric machine 210 and a ready-to-use connector 271 configured to connect the cooling device to the electric machine 210. The heat transfer fluid therefore passes directly from the module 221 to the electric machine 210. As in Figure 2(a), the connections therefore form blind connections when the module 221 is assembled to the electric machine 210 via the host structure.

[0067] The module 221 also comprises a fixing means 261 present on one of its lateral faces and placed opposite the electrical machine 210 making it possible to assemble the module 221 to the electrical machine 210. This makes it possible to reinforce the assembly of the modules to the electrical machine.

[0068] Figure 2(c) shows an example of a ready-to-use connector 292 present on the face 222a of the power electronics module 222 opposite the electrical machine 210. This connector 292 makes it possible to transmit an electrical signal to the machine 210.

[0069] Figure 3 shows, schematically and partially, positioning guides 342, 3421 present on a power electronics module 322 as described with reference to Figures 1 and 2. As indicated in Figure 2, the power electronics module 322 may comprise on its face 322a, facing the electrical machine, ready-to-use connectors 352, 392 and 372 configured to transmit an electrical signal (connector 392) and electrical power (reference 352) to the electrical machine and connect the cooling device to the electrical machine (connector 3722).

[0070] As shown in Figure 3(b), the heat transfer fluid of the cooling device circulates around the module 322 by entering through the connector 3722 which is connected to the cooling device, then into the circulation circuit 3721, and exits through the connector 372 to go towards the electric machine.

[0071] The module 322 comprises a first positioning guide 342 for positioning the module 322 on the host structure 330 (figure 3(a)). This first positioning guide 342 more particularly makes it possible to guide the module 322 on the host structure and to preposition the various ready-to-use connectors 352, 372 of the module 322 opposite the corresponding inputs of the electrical machine. This first positioning guide 342 may, for example, be formed of a shape present on the module 322 which one seeks to introduce and then slide into a slot present on the host structure 330.

[0072] The module 322 also includes a second positioning guide 343 for positioning the module 322 on the electrical machine (Figure 3(b)). This second positioning guide 343 may, for example, be a positioning pin that is to be inserted into a slot or hole present on the electrical machine. It allows the module 322 to be precisely aligned with the electrical machine to ensure that the ready-to-use connectors 352, 372 enter the corresponding inputs of the electrical machine.

[0073] Figure 4 shows, schematically and partially, ready-to-use connectors 452, 472, 492 of a power electronics module 422 as well as a positioning guide 443.

[0074] As described previously (figure 3), the power electronics module 422 comprises on its face 422a facing the electric machine a positioning guide, and more particularly a positioning pin 443 for precisely aligning the module 422 with the electric machine, as well as a ready-to-use connector 472 for connecting the cooling device to the electric machine and a ready-to-use connector 492 for transmitting an electrical signal to the electric machine.

[0075] In this second embodiment, the power electronics module 422 comprises on its lateral face 422b (face parallel to the axis of the rotor of the electric machine and which is not opposite the empty zone delimited by the structure for accommodating the power electronics modules) a ready-to-use connector 452. This ready-to-use connector 452 is configured to transmit electrical power from the module 422 to the electric machine.

[0076] The ready-to-use connectors placed on the 422a face or on the 422b face of the 422 module thus make it possible to eliminate the power harnesses and cables between the power electronics device and the electric machine. This reduces the overall mass and volume of the electric propulsion system. In addition, by eliminating the power harnesses, it is also possible to reduce, or even eliminate, the filters dedicated to electromagnetic interference.

[0077] Figure 5 shows, schematically and partially, fixing means between two power electronics modules 521 and 522 (figure 5(a)) and between the power electronics modules 521, 522 and the electrical machine 510 (figure 5(b)).

[0078] As indicated with reference to the preceding figures and shown in figures 5(a) and 5(b), the two power electronics modules 521 and 522 may comprise means 581, 582 for fixing to the electrical machine 510. These means 581, 582 more particularly make it possible to attach the face 522a, opposite the electrical machine, to the electrical machine so that the modules are held in position and the ready-to-use connectors are properly placed in the connectors present on the electrical machine.

[0079] The fixing means 581, 582 can also make it possible to ensure the electrical grounding of the electrical machine and the modules 521, 522 via the contacts of conductive surfaces, when their surfaces are conductive.

[0080] The module 522 includes fixing means 580 allowing it to be fixed to another module.

[0081] The modules may also include fixing means allowing them to be assembled to the host structure.

[0082] The various means of attachment 580, 581, 582 to the host structure, to the electric machine and / or between the modules make it possible to increase the overall rigidity of the electric propulsion system.

[0083] Ready-to-use connectors dedicated to the circulation of the heat transfer fluid of the cooling device between the modules and the electrical machine can be rigid to participate in the alignment of the modules with the electrical machine.

[0084] Depending on a particular feature of the system, ready-to-use connectors can be plug-in connectors.

[0085] According to another particular feature of the system, the connectors can be rigid and pluggable allowing “blind” assembly.

[0086] The electric machine is, for example, a permanent magnet synchronous motor.

[0087] The power electronics device may have a power of between 200 kW and 800 kW, wherein each power electronics module may have a power of between 100 kW and 300 kW.

[0088] The electric propulsion system according to the invention may for example be a conventional aircraft propulsion system (CTOL) or a vertical takeoff and landing (VTOL) aircraft propulsion system or a short takeoff and landing (STOL) aircraft propulsion system.

[0089] The invention also relates to an aircraft comprising an electric propulsion system according to the invention.

Claims

Claims

1. Electric propulsion system (100) for an aircraft comprising: - an electric machine (110, 210, 510) configured to operate as a motor or generator and comprising a rotor, - a direct voltage source, - a power electronics device (120) connected to the direct voltage source and to the electrical machine, and - a cooling device (172, 173, 3721, 3722) by heat transfer fluid of the electric machine and the power electronics device, characterized in that the power electronics device comprises at least two interchangeable power electronics modules (121, 122, 123, 124, 221, 222, 322, 422, 521, 522) configured to form, each, an electrical path from the DC voltage source to the electric machine, each module comprising at least a first ready-to-use connector (252, 292, 392, 492) configured to be connected to the electric machine and transmit an electrical signal, a second ready-to-use connector (151, 154, 251, 282, 352, 452) configured to be connected to the electric machine and transmit an electrical power, and a third ready-to-use connector (271, 272, 372, 472) configured to connect the cooling device to the electrical machine,and in that the electric propulsion system comprises a reception structure (130, 330) attached to the electric machine on which the power electronics modules are placed and delimiting an empty zone (135) around the axis of the rotor of the electric machine.,

2. An electric propulsion system according to claim 1, wherein at least one of the ready-to-use connectors (151, 154, 251, 252, 282, 292, 272, 271, 352, 372, 392, 472, 492) is placed on a face (221a, 222a, 322a, 422a) of the power electronics modules (221, 222, 322, 422) facing the electric machine.

3. An electric propulsion system according to any one of claims 1 or 2, wherein at least one of the plug-and-play connectors (452) is placed on a lateral face (422b) of the power electronics modules (422).

4. An electric propulsion system according to any one of claims 1 to 3, wherein the receiving structure (130, 330) comprises positioning guides (142, 143, 342, 343, 443) ensuring automatic mutual alignment between the ready-to-use connectors of the power electronics modules and the electric machine.

5. An electric propulsion system according to any one of claims 1 to 4, comprising fixing means (161, 164, 261, 580, 581, 582) placed on the power electronics modules configured to assemble the power electronics modules to the host structure and / or assemble the power electronics modules to the electric machine and / or assemble the power electronics modules together.

6. An electric propulsion system according to any one of claims 1 to 5, wherein each power electronics module has a power of between 100 kW and 300 kW.

7. An electric propulsion system according to any one of claims 1 to 6, wherein the electric machine is a permanent magnet synchronous motor.

8. An electric propulsion system according to any one of claims 1 to 7, comprising a propeller pitch actuator placed in the empty area in the rotor axis.

9. An electric propulsion system according to any one of claims 1 to 8, wherein the system is a vertical takeoff and landing aircraft propulsion system or a short takeoff and landing aircraft propulsion system or a conventional aircraft propulsion system.

10. An aircraft with electrical propulsion or with thermal / electric hybrid propulsion comprising an electric propulsion system according to any one of claims 1 to 9.

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