Electrical power supply system for an aircraft's electric propulsion system.

Abstract

Electrical power supply system of an aircraft electric propulsion system. The electrical power supply system (10) of an aircraft electric propulsion system (4) (1) comprises: - at least two first fuel cell assemblies (FC11, FC12), intended to electrically power an electric motor driving a propulsion propeller; - a first compressor (C1) configured to supply compressed air to at least some of the at least two first fuel cell assemblies (FC11, FC12); and - a first electric motor (M1) intended to drive the first compressor. The first electric motor (M1) comprises at least two electrical windings (W1a, W1b), each electrical winding being electrically powered from a separate fuel cell assembly among the at least two first fuel cell assemblies (FC11, FC12). Figure for the abstract: Fig. 2

Description

Title of the invention: Electrical power supply system for an electric propulsion system of an aircraft.

[0001] The invention relates to the field of electric propulsion of aircraft. An electrically powered aircraft includes at least one electric propulsion system. In one embodiment, an aircraft's electric propulsion system comprises fuel cells that electrically power an electric motor or a set of electric motors driving a propeller. For operational safety reasons, such a propulsion system includes at least two sets of fuel cells to electrically power an electric motor or a set of electric motors driving the propeller. Thus, if one of the fuel cell sets fails, the propeller continues to be driven, albeit at reduced power. To operate, a fuel cell system requires an input of hydrogen (H2) and oxygen (O2). The hydrogen is typically supplied from a hydrogen tank onboard the aircraft. Oxygen is present in sufficient quantities in ambient air, so it is not necessary to install an oxygen tank onboard the aircraft. However, a compressor is required to compress the ambient air before it is fed into the fuel cell system, ensuring that the system receives enough oxygen. This compressor is usually driven by an electric motor. For improved efficiency, the compressor is often a turbocharger.

[0002] A conventional solution involves attaching a compressor to each fuel cell assembly and powering the electric motor driving the compressor with electricity produced by that fuel cell assembly. If the fuel cell assembly fails, the electric motor driving the compressor loses power, causing the compressor to stop. However, this is not a problem since the fuel cell assembly is already out of service.

[0003] As previously stated, each aircraft's electric propulsion system comprises at least two fuel cell assemblies. The number of fuel cell assemblies may even be higher, depending on the power required to propel the aircraft. Since a compressor is associated with each fuel cell assembly, the aircraft comprises a significant number of compressors, each with a corresponding mass and a large footprint. Therefore, it would be desirable to reduce the number of compressors.

[0004] One solution envisaged by the inventor would consist of using a single compressor connected to several fuel cell assemblies to supply them with compressed air. An electric motor driving the compressor would be powered by one of the fuel cell assemblies. In the event of a failure of the fuel cell assembly, the electric motor's power supply would be switched to another fuel cell assembly, to which the compressor would supply compressed air. This solution reduces the number of compressors on board the aircraft and consequently their mass and size. However, in the event of a failure of the electric motor powering the compressor or of a failure of an electric motor controller, none of the fuel cell assemblies connected to this compressor would receive compressed air.Therefore, a simple failure of the electric motor or its controller would cause a failure of all the fuel cell assemblies connected to that compressor. This would be unacceptable from the point of view of the aircraft's propulsion system availability. Description of the invention

[0005] The present invention aims in particular to provide a solution to this problem. It relates to a power supply system for an electric propulsion system of an aircraft, the power supply system comprising:

[0006] - at least two fuel cell assemblies, among which at least two first fuel cell assemblies, designed to electrically power an electric motor or a set of electric motors driving a propulsion propeller;

[0007] - a first compressor configured to supply compressed air to at least one part of at least the first two fuel cell assemblies; and

[0008] - a first electric motor intended to drive the first compressor.

[0009] The power supply system is notable in that the first electric motor intended to drive the first compressor comprises at least two electric windings, each electric winding being electrically powered from a separate set of fuel cells among the at least first two sets of fuel cells.

[0010] Thus, the invention makes it possible to have a compressor common to at least two fuel cell assemblies and therefore to reduce the mass and size of the compressors carried on board the aircraft. Since the compressor is a mechanical device, its probability of failure is sufficiently low to be acceptable from the point of view of the availability of the aircraft's propulsion system. Given that The electric motor driving the compressor comprises at least two electrical windings powered by separate fuel cell assemblies. The electric motor can continue to operate at reduced power in the event of a failure in one of the electrical windings or in a controller supplying power to one of the windings. This ensures the availability of the aircraft's propulsion system.

[0011] According to a first possibility, the first compressor is configured to supply compressed air to two of said fuel cell assemblies and the first electric motor intended to drive the first compressor comprises two electric windings each electrically powered from one of said two fuel cell assemblies.

[0012] According to a second possibility, the first compressor is configured to supply compressed air to three of said fuel cell assemblies and the first electric motor intended to drive the first compressor comprises three electric windings each electrically powered from one of said three fuel cell assemblies.

[0013] In one embodiment, the power supply system comprises:

[0014] - at least four fuel cell assemblies, among which said at at least two first fuel cell assemblies and at least two second fuel cell assemblies, these at least four fuel cell assemblies being intended to electrically power the electric motor or set of electric motors driving the propulsion propeller;

[0015] - a second compressor configured to supply compressed air to at least one part of at least two second sets of fuel cells; and

[0016] - a second electric motor intended to drive the second compressor, the second electric motor comprising at least two electric windings, each electric winding being electrically powered from a separate set of fuel cells among the at least two second sets of fuel cells.

[0017] In particular, the compressor is of the turbocharger type.

[0018] In a particular embodiment, the power supply system further includes a cooling system for at least a portion of the at least two first fuel cell assemblies, this cooling system comprising a first fan which includes at least two electrical windings, each electrical winding of the first fan being electrically powered from a separate fuel cell assemblies among the at least two first fuel cell assemblies.

[0019] In the particular embodiment, according to the first possibility, the cooling system is configured to cool two sets of fuel cells and the first fan comprises two electrical windings each electrically powered from one of said two sets of fuel cells.

[0020] In the particular embodiment, according to the second possibility, the cooling system is configured to cool three sets of fuel cells and the first fan comprises three electrical windings each electrically powered from one of said three sets of fuel cells.

[0021] In one embodiment, the cooling system further comprises a second fan intended to cool at least a portion of the at least two second fuel cell assemblies, the second fan comprising at least two electrical windings, each electrical winding of the second fan being electrically powered from a separate fuel cell assembly among the at least two second fuel cell assemblies.

[0022] The invention also relates to an aircraft comprising such an electrical power supply system for an electric propulsion system. Description of the implementation methods

[0023] The invention will be better understood upon reading the following description and examining the accompanying figures.

[0024] Fig. 1 is a view of an aircraft comprising an electrical power supply system for an electric propulsion system.

[0025] Fig. 2 schematically illustrates an electrical power supply system for an electric propulsion system of an aircraft, according to an embodiment of the invention.

[0026] Fig. 3 schematically illustrates an electrical power supply system for an electric propulsion system of an aircraft, according to another embodiment of the invention.

[0027] Figure 4 schematically illustrates an electrical power supply system for an electric propulsion system of an aircraft, according to another embodiment of the invention.

[0028] Figure 5 schematically illustrates an electrical power supply system for an electric propulsion system of an aircraft, according to another embodiment of the invention.

[0029] Figure 6 schematically illustrates an electrical power supply system for an electric propulsion system of an aircraft, according to another embodiment of the invention.

[0030] The electrical power supply system 10 shown in [Fig. 2] is intended to power an electric propulsion system 4 of an aircraft such as aircraft 1 shown in [Fig. 1]. It is, for example, installed in an avionics bay 2 of the aircraft. The electric propulsion system 4 comprises at least one electric motor driving a propeller. The electrical power supply system 10 comprises at least two first fuel cell assemblies FC11 and FC12 intended to electrically power at least one electric motor. It also comprises a first compressor Cl intended to supply compressed air to the first two fuel cell assemblies FC11 and FC12. The first compressor Cl is mechanically coupled to a first electric motor ML. The assembly formed by the first electric motor ML and the first compressor Cl is also called a motor-compressor.The first electric motor M1 comprises two electric windings W1a and W1b, each electric winding being electrically powered from a separate fuel cell assembly among the at least first two fuel cell assemblies FC11 and FC12. Thus, the electric winding W1a is powered by the fuel cell assembly FC11, via a controller C1a, and the electric winding W1b is powered by the fuel cell assembly FC12, via a controller C1b. Without limiting the invention, other electric loads Z1a ... Z11j are electrically powered by the fuel cell assembly FC11, for example via an electrical distribution busbar B11, and other electric loads Z12a ... Z12k are electrically powered by the fuel cell assembly FC12, for example via an electrical distribution busbar B12.

[0031] In normal operation, when the FC11 and FC12 fuel cell assemblies are producing electricity, the two electric windings Wla and Wlb of the first electric motor Ml are electrically powered, respectively, via the controllers Cia and Clb. This allows the first electric motor Ml to operate at its rated power and drive the first compressor Cl, which can thus operate at its rated power.

[0032] In the event of a failure of one of the two fuel cell assemblies, for example FC11, only the electric winding Wlb of the electric motor Ml is powered by the other fuel cell assembly FC12. Consequently, the electric motor Ml can only operate at half its rated power. The compressor Cl, driven by the electric motor Ml, can then also only operate at half its rated power. The fact that the compressor Cl operates at only half its rated power does not pose a problem in such circumstances, since only the fuel cell assembly FC12 needs compressed air to to operate, with the FC11 fuel cell assembly malfunctioning. At least one propulsion motor is thus electrically powered by the FC12 fuel cell assembly, allowing this propulsion motor to continue operating, albeit at half its nominal power.

[0033] In the event of a failure of one of the controllers Cia or Clb, or in the event of a failure of one of the electrical windings Wla or Wlb of the first electric motor, the first electric motor Ml is electrically powered by only one of the two windings. As in the previous failure scenario, it can only operate at half its rated power, as can the first compressor Cl. Consequently, the two fuel cell assemblies FC11 and FC12 then receive an airflow corresponding to approximately half the airflow required for their rated operation. These two fuel cell assemblies FC11 and FC12 can thus deliver approximately half their rated power, which allows the propulsion engine to continue operating, albeit at a reduced power of approximately half its rated power.

[0034] In the embodiment shown in [Fig. 3], the power supply system 10 further comprises a third first set FC13 of fuel cells, and the electric motor M1 comprises a third electric winding W1e electrically powered by the set FC13 of fuel cells via a controller Clc. Without limiting the invention, other electrical loads Z13a ... Z13n are electrically powered by the set of fuel cells FC13, for example via an electrical distribution busbar B13.

[0035] In the event of a failure of one of the first three fuel cell assemblies FC11, FC12, FC13, two of the three electrical windings Wla, Wlb, Wlc of the electric motor Ml remain electrically energized. Consequently, the electric motor Ml can only operate at two-thirds of its rated power. The compressor Cl, driven by the electric motor Ml, can then also only operate at two-thirds of its rated power. The fact that the compressor Cl operates at only two-thirds of its rated power does not pose a problem in such circumstances, since only two of the first three fuel cell assemblies FC11, FC12, FC13 then require compressed air to operate, one of said fuel cell assemblies being inoperative.At least one propulsion motor is thus electrically powered by two of the first three fuel cell assemblies, allowing this propulsion motor to continue operating, albeit at a reduced power output of one-third compared to its nominal power. The same applies in the event of a failure of one of the controllers Cia, Clb, or Clc, or in the event of a failure of one of the electrical windings Wla, Wlb, or Wlc.

[0036] In the embodiment shown in [Fig. 5], the power supply system 10 comprises a first part similar to the power supply system corresponding to the embodiment shown in [Fig. 2]. This first part comprises the first two fuel cell assemblies FC11 and FC12 and the first electric motor M1 mechanically coupled to the first compressor Cl. The first two fuel cell assemblies FC11 and FC12 are intended to electrically supply at least one electric motor driving the propulsion propeller. The first electric motor M1 comprises two electric windings W1a and W1b, each electric winding being electrically supplied from a separate fuel cell assembly among the at least first two fuel cell assemblies FC11 and FC12.Thus, the electric winding W1a is powered by the fuel cell assembly FC11, via a controller Cia, and the electric winding W1b is powered by the fuel cell assembly FC12, via a controller Clb. The power supply system 10 further includes a second part comprising two second fuel cell assemblies FC21 and FC22 and a second electric motor M2 mechanically coupled to a second compressor C2. Like the first two fuel cell assemblies FC11 and FC12, the second two fuel cell assemblies FC21 and FC22 are also intended to electrically power at least one electric motor driving the propulsion propeller of the electric propulsion system 4.The second electric motor M2 comprises two electric windings W2a and W2b, each electric winding being electrically powered from a separate fuel cell set among the at least two second fuel cell sets FC21 and FC22. Thus, the electric winding W2a is powered by the fuel cell set FC21, via a controller C2a, and the electric winding W2b is powered by the fuel cell set FC22, via a controller C2b.

[0037] In normal operation, the fuel cell assemblies FC11, FC12, FC21, and FC22 produce electricity. Consequently, the two electrical windings Wla and Wlb of the first electric motor Ml are electrically powered, respectively, via the controllers Cia and Clb. This allows the first electric motor Ml to operate at its rated power and drive the first compressor Cl, which can thus operate at its rated power. Similarly, the two electrical windings W2a and W2b of the second electric motor M2 are electrically powered, respectively, via the controllers C2a and C2b. This allows the second electric motor M2 to operate at its nominal power and to drive the second compressor C2 which can thus operate at its nominal power.

[0038] In the event of a failure of one of the four fuel cell assemblies FC11, FC12, FC21, and FC22, the compressor C1 and C2 that is normally partially powered by the failed fuel cell assembly can only operate at half its rated power, as already described in the embodiment illustrated in [Fig. 2]. This allows the other fuel cell assembly supplied with air by this compressor to operate normally. Consequently, apart from the failed fuel cell assembly, the other three fuel cell assemblies operate at their rated power. At least one propulsion motor is thus electrically powered by these three fuel cell assemblies, enabling this propulsion motor to continue operating, albeit at a reduced power of one-quarter compared to its rated power.

[0039] In the event of a failure of one of the four controllers Cia, Clb, C2a, or C2b, or in the event of a failure of one of the four electrical windings Wla, Wlb, W2a, or W2b, as already described in the embodiment illustrated in [Fig. 2], the two fuel cell assemblies supplied with air by the compressor affected by the failure continue to operate at a reduced power of approximately half their rated power. The other two fuel cell assemblies operate at their rated power. Consequently, the propulsion engine continues to operate, albeit at a reduced power of approximately one-quarter of its rated power.

[0040] The power supply system 10 shown in [Fig. 4] is similar to that shown in [Fig. 2]. It further includes a first fan V1 that is part of a cooling system for the first two fuel cell assemblies FC11 and FC12. This fan is, for example, integrated into a heat exchanger designed to cool a heat transfer fluid in a cooling circuit for the first two fuel cell assemblies by heat exchange with air from outside the aircraft. Like the first electric motor M1, the first fan V1 comprises two electric windings, each electric winding being electrically powered from a separate fuel cell assembly among the at least first two fuel cell assemblies FC11 and FC12.Thus, one of the electrical windings is powered by the FC11 fuel cell assembly, via an Ela controller, and the other electrical winding is powered by the FC12 fuel cell assembly, via an Elb controller.

[0041] Using a common fan V1 for cooling the FC11 fuel cell assembly and the FC12 fuel cell assembly presents the advantage of reducing the mass and size of the cooling system compared to a conventional solution in which an independent fan would be used to cool each of said fuel cell assemblies.

[0042] In the event of a failure of one of the two fuel cell sets, for example FC11, only one of the electrical windings of the first fan VI is powered, by the other fuel cell set FC12. Consequently, the first fan V1 can only operate at half its rated power. As a result, the cooling system can only operate at half its rated power. This does not pose a problem in such circumstances, since only the FC12 fuel cell set needs to be cooled, the FC11 fuel cell set being inoperative. At least one propulsion motor is thus electrically powered by the FC12 fuel cell set, which allows this propulsion motor to continue operating, albeit at half its rated power.

[0043] In the event of a failure of either the Ela or Elb controllers, or in the event of a failure of one of the electrical windings of the first fan VI, the first fan V1 is electrically powered by only one of its two windings. As in the previous failure scenario, it can only operate at half its rated power. Consequently, the cooling system can only operate at half its rated power. This allows both fuel cell assemblies FC11 and FC12 to operate at substantially half their rated power, which enables the propulsion engine to continue operating, albeit at a power level reduced by substantially half compared to its rated power.

[0044] In an embodiment not shown in the figures, the power supply system 10 is similar to that shown in [Fig. 3] and further comprises a first fan V1 like that shown in [Fig. 4]. The first fan V1 comprises three electrical windings powered respectively by the fuel cell assemblies FC11, FC12, and FC13. In the event of a failure of one of the first three fuel cell assemblies FC11, FC12, FC13, two of the three electrical windings of the first fan V1 remain electrically powered. This allows the first fan V1 to operate at two-thirds of its rated power.The fact that fan V1 operates at only two-thirds of its rated power is not a problem in such circumstances, since only two of the first three fuel cell assemblies (FC11, FC12, FC13) need to be cooled to operate, one of said fuel cell assemblies being out of service. At least one propulsion motor is thus electrically powered by two of the first three fuel cell assemblies, allowing this propulsion motor to continue operating, albeit at a reduced power output of one-third. compared to its nominal power. The same applies in the event of a failure of one of the controllers supplying the electrical windings of the first fan VI or in the event of a failure of one of the electrical windings.

[0045] The power supply system 10 shown in [Fig. 6] is similar to that shown in [Fig. 5]. It further includes a first fan V1, which is part of a cooling system for the first two fuel cell assemblies FC11 and FC12. This first fan is, for example, integrated into a heat exchanger designed to cool a heat transfer fluid in a cooling circuit for the first two fuel cell assemblies by exchanging heat with air from outside the aircraft. Like the first electric motor M1, the first fan V1 comprises two electric windings, each electric winding being electrically powered from a separate fuel cell assembly among the at least first two fuel cell assemblies FC11 and FC12.Thus, one of the electrical windings is powered by the FC11 fuel cell assembly via an Ela controller, and the other electrical winding is powered by the FC12 fuel cell assembly via an Elb controller. Similarly, the power supply system 10 also includes a second fan V2, which is part of a cooling system for the two second fuel cell assemblies, FC21 and FC22. This second fan is, for example, integrated into a heat exchanger designed to cool a heat transfer fluid in a cooling circuit for the two second fuel cell assemblies by exchanging heat with air from outside the aircraft.The second fan V2 comprises two electrical windings, each electrically powered from a separate fuel cell set among the at least two second fuel cell sets FC21 and FC22. Thus, one of the electrical windings is powered by the FC21 fuel cell set, via an E2a controller, and the other electrical winding is powered by the FC22 fuel cell set, via an E2b controller.

[0046] In normal operation, the fuel cell assemblies FC11, FC12, FC21, and FC22 produce electricity. Consequently, the two electrical windings of the first fan V1 are powered, respectively, via the controllers Ela and Elb. This allows the first fan V1 to operate at its rated power. Similarly, the two electrical windings of the second fan V2 are powered, respectively, via the controllers E2a and E2b. This allows the second fan V2 to operate at its rated power.

[0047] In the event of a failure of one of the four fuel cell assemblies FC11, FC12, FC21, and FC22, the fan VI and V2 that is normally partially powered by the failed fuel cell assembly can then only operate at half its rated power, as already described in the embodiment illustrated in [Fig. 4]. This allows the other fuel cell assembly cooled by this fan to operate normally. Consequently, apart from the failed fuel cell assembly, the other three fuel cell assemblies operate at their rated power. At least one propulsion motor is thus electrically powered by these three fuel cell assemblies, which allows this propulsion motor to continue operating, albeit at a reduced power of one-quarter compared to its rated power.

[0048] In the event of a failure of one of the four controllers E1a, E1b, E2a, or E2b, or in the event of a failure of one of the four electrical windings of the two fans, as already described in the embodiment illustrated in [Fig. 4], the two fuel cell assemblies cooled by the fan affected by the failure continue to operate at a power reduced by approximately half compared to their rated power. The other two fuel cell assemblies operate at their rated power. Consequently, the propulsion engine continues to operate, albeit at a power reduced by approximately one-quarter compared to its rated power.

[0049] The power supply of the electric motor or the set of electric propulsion motors of the aircraft is not shown in figures 2 to 6 in order not to overload these figures.

Claims

Demands

1. 1) Power supply system (10) of an electric propulsion system (4) of an aircraft (1), the power supply system comprising: - at least two fuel cell assemblies, of which at least two first fuel cell assemblies (FC11, FC12), intended to electrically power an electric motor or a set of electric motors driving a propulsion propeller; - a first compressor (Cl) configured to supply compressed air to at least a part of the at least two first fuel cell assemblies (FC11, FC12);and - a first electric motor (Ml) intended to drive the first compressor, the first electric motor (Ml) comprising at least two electric windings (Wla, Wlb), each electric winding being electrically powered from a separate fuel cell set among the at least first two fuel cell sets (FC11, FC12), the power supply system (10) being characterized in that it further comprises a cooling system for at least a portion of the at least first two fuel cell sets (FC11, FC12), this cooling system comprising a first fan (VI) which comprises at least two electric windings, each electric winding of the first fan being electrically powered from a separate fuel cell set among the at least first two fuel cell sets.;

2. 2) Power supply system according to claim 1, characterized in that the first compressor (Cl) is configured to supply compressed air to two of said fuel cell assemblies and the first electric motor (Ml) intended to drive the first compressor comprises two electric windings (Wla, W1b) each electrically powered from one of said two fuel cell assemblies.

3. 3) Power supply system according to claim 1, characterized in that the first compressor (Cl) is configured to supply compressed air to three of said stacks fuel cell and the first electric motor (Ml) intended to drive the first compressor comprises three electric windings (Wla, Wlb, Wlc) each electrically powered from one of said three fuel cell assemblies.

4. 4) Power supply system according to claim 1, characterized in that it comprises: - at least four fuel cell assemblies (FC11, FC12, FC21, FC22), of which said at least two first fuel cell assemblies (FC11, FC12) and at least two second fuel cell assemblies (FC21, FC22), these at least four fuel cell assemblies being intended to electrically power the electric motor or set of electric motors driving the propulsion propeller; - a second compressor (C2) configured to supply compressed air to at least a part of the at least two second fuel cell assemblies (FC21, FC22);and - a second electric motor (M2) intended to drive the second compressor (C2), the second electric motor comprising at least two electric windings (W2a, W2b), each electric winding being electrically powered from a separate fuel cell set among the at least two second fuel cell sets.;

5. 5) Power supply system according to any one of the preceding claims, characterized in that the compressor is of the turbocharger type.

6. 6) Power supply system according to claim 2, characterized in that the cooling system is configured to cool two sets of fuel cells and the first fan (VI) comprises two electrical windings each electrically powered from one of said two sets of fuel cells.

7. 7) Power supply system according to claim 3, characterized in that the cooling system is configured to cool three sets of fuel cells and the first fan (VI) comprises three electrical windings each electrically powered from one of said three sets of fuel cells.

8. 8) Power supply system according to claim 4, characterized in that the cooling system further comprises a second fan (V2) intended to cool at least a part of the at least two second fuel cell assemblies (FC21, FC22), the second fan comprising at least two electrical windings, each electrical winding of the second fan being electrically powered from a separate fuel cell assembly among the at least two second fuel cell assemblies.

9. 9) Aircraft (1), characterized in that it comprises an electrical power supply system (10) according to any one of the preceding claims.

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