Aircraft electric or hybrid propulsion architecture

Abstract

Disclosed is an aircraft electric or hybrid propulsion architecture comprising at least two propulsion trains, each propulsion train comprising at least one electric motor (Moteur1, Moteur2) powered by at least two power sources (Source1, Source2, Source3) of the propulsion architecture through at least two power-supply paths that each comprise at least one power converter, and one electrical protection delivering a DC voltage to an HVDC bus (HVDC bus1, HVDC bus2), each HVDC bus distributing this DC voltage to at least one electric motor through at least one power converter and one electrical protection, the propulsion architecture comprising power-supply paths that are at least partially dissimilar and preferably completely dissimilar.

Description

[0001] Description

[0002] Title of the invention: Electric or hybrid aircraft propulsion architecture

[0003] Technical Field

[0004] The present invention relates to the field of electric or hybrid aircraft propulsion architectures. It relates more particularly to a propulsion architecture which is tolerant to random failures and robust to systematic failures.

[0005] Prior art

[0006] The propulsion system architectures of fixed-wing and rotary-wing aircraft are generally tolerant to single random failure but are not tolerant to systematic failure, particularly for certain critical events likely to lead to the loss of the aircraft (through loss of integrity of propulsion system control, or loss of the propulsion system itself). This is even more true for vertical take-off and landing (VTOL) aircraft used for urban mobility purposes, whose propulsion function contributes directly to the lift function, and for which the level of safety expected to avoid tragic losses and human disasters is then even higher than that required for traditional aircraft whose probability of crashing in urban areas is very low.

[0007] To overcome the loss of control integrity, it is known to redundantly implement control devices so that after the first random failure has been sanctioned, the control function remains ensured by redundancy. To overcome the loss of the propulsion system, it is known to maintain a minimum of propulsive resources in operation to be able to perform a safe landing, i.e. to ensure an aircraft trajectory with the required safety margins. These solutions, acceptable for traditional aircraft with thermal engines, are no longer acceptable for the architectures of electric or hybrid propulsion chains which must be more efficient with regard to random and systematic failures.

[0008] Furthermore, climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies both to new aircraft types and those currently in operation, requiring the implementation of technological solutions to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0009] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of aircraft.

[0010] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0011] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels. The present invention is thus the result of this technological research aimed at significantly improving aircraft performance and contributing to the reduction of their environmental impact.

[0012] Statement of the invention

[0013] In view of the above, the main aim of the present invention is to provide an electric or hybrid propulsion and / or lift architecture comprising at least two propulsion chains and which, in normal mode and in single or multiple failure states, offers the greatest margin in power and probability of non-loss of the propulsion function.

[0014] These aims are achieved by an aircraft electric or hybrid propulsion architecture comprising at least two propulsion chains, each propulsion chain comprising at least one electric motor powered from at least two energy sources of the propulsion architecture through at least two energy supply paths, each energy supply path comprising at least one energy converter and an electrical protection delivering a direct voltage for an HVDC bus, each HVDC bus distributing this direct voltage to at least one electric motor through at least one of said energy converters and one of said electrical protections, the propulsion architecture being characterized in that the energy supply paths are at least partially dissimilar, and preferably totally dissimilar.

[0015] Thus, through this dissimilarity of the energy supply paths, we obtain an architecture tolerant to random failures and robust to systematic failures. We can thus obtain a propulsion system potentially eligible for the rank of critical system, delivering the power necessary for flight control with a very high level of safety and minimizing to an acceptable level the vulnerabilities and threats of potential failures.

[0016] In the invention, the diversification or dissimilarity is therefore present in all the elements of the propulsion architecture, and makes it possible to maintain independence between potentially dangerous failures. Preferably, the energy source, the energy converter, the electrical protection and the HVDC bus of an energy supply path are each dissimilar respectively to the energy source, the energy converter, the electrical protection and the HVDC bus of at least one other energy supply path.

[0017] Advantageously, the electric motors of the at least two propulsion chains are dissimilar.

[0018] The architecture may further include bus electrical protection mounted between two dissimilar HVDC buses.

[0019] Preferably, the bus electrical protection comprises a series assembly of a controlled elementary electrical protection, preferably comprising a contactor, and a non-controlled elementary electrical protection, preferably comprising a circuit breaker.

[0020] Applied to a three-bus HVDC ring power distribution network, the architecture includes at least one HVDC bus that is partially or totally dissimilar to the other two.

[0021] Applied to a four-bus HVDC ring power distribution network, the architecture includes at least one HVDC bus that is partially or totally dissimilar to the other three.

[0022] Preferably, two adjacent HVDC buses of the power distribution network are connected together by a series assembly of two bus electrical protections, these two bus electrical protections comprising two dissimilar elementary electrical protections, preferably a controlled elementary electrical protection and a non-controlled elementary electrical protection.

[0023] The invention also relates to an electric or hybrid aircraft comprising an electric or hybrid propulsion architecture as mentioned above.

[0024] Brief description of the drawings 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 in any limiting nature, among which:

[0025] [Fig. 1] Figure 1 illustrates a first example of a propulsion architecture in accordance with the invention,

[0026] [Fig. 2] Figure 2 illustrates a second example of a propulsion architecture in accordance with the invention,

[0027] [Fig. 3] Figure 3 shows a first example of a power distribution network applicable to either of the architectures of Figures 1 and 2,

[0028] [Fig. 4] Figure 4 shows a second example of a power distribution network applicable to either of the architectures of Figures 1 and 2,

[0029] [Fig. 5] Figure 5 illustrates a third example of a propulsion architecture according to the invention, and

[0030] [Fig. 6] Figure 6 illustrates a fourth example of a propulsion architecture in accordance with the invention.

[0031] Description of the embodiments

[0032] In the remainder of the description, it is considered that all elements of the architecture are in active operation and are able to contribute to compensating for systematic failures, as well as random failures, so as to maintain the aircraft's ability to perform a safe landing with an electric motor (a single propulsion unit), i.e. to provide an emergency power level necessary to compensate for the loss(es) of the other propulsion units.

[0033] To ensure that each motor (or group of motors referred to as Group 1 and Group 2 in the remainder of the description) operates independently of each other if there are two (or of each other if there are more than two), it is necessary to ensure that the consumers that are these electric motors are independent and that the energy sources that supply them are also independent. It is recalled that the propulsion system refers to the function and the components that make it possible to produce and regulate the rotational speed and / or the torque on each drive shaft of each electric motor. This production of power on multiple output shafts is controlled by the requests issued by the aircraft's flight control system.

[0034] Several propulsion system architectures will be described below and it will be explained for each of them how this independence is ensured to be tolerant to random or systematic single failure. For this, diversification (or dissimilarity) will be used, which consists of differentiating as much as possible the hardware or software characteristics of the objects that we wish to make independent, so that the more different characteristics there are between the same objects, the lower the probability of failures of these objects due to a common cause will be.

[0035] In the remainder of the description, elements or power supply paths of the propulsion architecture are said to be “dissimilar” when they meet this diversification criterion, in particular when their hardware or software characteristics are different.

[0036] Indeed, the fact that objects are very similar or even identical creates a dependency between these objects, that is to say that they are no longer statistically independent and that the failure of one of these objects is statistically correlated with the failure of another of these objects. This dependency can be due to intrinsic functional or physical characteristics, deliberate or not, which are vulnerabilities such as for example: behavior, material, geometry, ..., or to intrinsic or extrinsic characteristics of objects, deliberate or not, which result from interactions between objects, or from behavior in a given situation.

[0037] We can consider that there are two subsets of causes that make failures dependent. The first subset relates to cascading failures which are failures where there is physical or logical coupling between non-redundant objects. There is first a primary failure of the first object, then by propagation, the secondary failure of the second object, etc..., until the propagation stops at the final element that fails, or the propagation stops on an object more robust than its predecessor at the failure. The second subset concerns common cause failures which can reveal the dependence of several objects in the same time interval, such as a flight or a mission, and which can result from a coupling mechanism of redundant objects, or from a common cause initiator, at a certain moment of time (example: a morning with much more humidity than usual, a higher vibration level than usual, ...). The common cause may appear to have a random character because the initiator may appear in time randomly to create the conditions for the occurrence of failures of several objects in the flight. However, when the initiator occurs (stress, particular request), the effects of the failures are the same due to the lack of robustness of the objects with regard to the equivalent conditions which generate the failure of each of the objects.

[0038] Also, the invention describes architectures tolerant to common causes leading to potentially critical systematic failures of the propulsion system, and which by reducing the common initiators and the coupling mechanisms prevent these common causes from leading to the much-feared events of the propulsion system (loss of integrity, loss of availability mentioned in the preamble).

[0039] Figure 1 shows a first example of propulsion system architecture according to the invention composed of at least two propulsion chains in which there are for each of them at least: an energy source, a first energy conversion element, an element for distributing the converted energy, a second element for converting the distributed energy, an element for transforming electrical energy into mechanical energy (electric motors) which drives a propeller, electrical protections and one or more control systems (not illustrated) for the different elements of the chain.

[0040] This is a propulsion architecture with two independent propulsion groups (Group 1 # Group ) (the # sign meaning this independence), the Group 1 motor not being of the same origin (for example different suppliers) as that of Group? (these two motors are therefore dissimilar), organized with two HVDC (High Voltage Direct Current) buses which are also independent: HVDC busl # HVDC bus2. For such a bus which technologically is a simple copper / aluminum bar, this independence will materialize by characteristics allowing to immunize itself from common causes with distinct materials, shapes, or suppliers.

[0041] To improve the availability of each HVDC bus, each HVDC bus is advantageously supplied according to more than one functional supply chain (or energy supply path) by several sources, two in this first configuration, one source of which is common to two functional supply chains. The common source 2 can be, for example, a non-rechargeable thermal battery, or a rechargeable element such as a fuel cell, or a supercapacitor as illustrated or even a thermal engine equipped with two alternators or a dual-channel alternator (also called a double star) supplying an HVAC bus (not shown), while sources 1 and 3 could be batteries.

[0042] Having more than one functional power supply chain allows to be tolerant to cases of single random failure which cause loss of bus power and therefore the complete bus (in this case each functional chain must be able to provide the maximum power required as a true redundancy) but cannot compensate for systematic failures which exist due to the similarity of the definition / design, manufacture, installation, use, and maintenance / repair of these redundant functional power supply chains.

[0043] Also, according to the invention, for this propulsion architecture to become tolerant to systematic failure and to satisfy the aforementioned independence condition HVDC busl # HVDC bus2, it is also necessary for these two power supply chains to be at least partially dissimilar, and preferably totally dissimilar.

[0044] This dissimilarity is illustrated by the solid or dotted outlines of the blocks concerned, the same outlines corresponding to similar objects. Thus, source 1 is similar to source 3 and source 2 is dissimilar to sources 1 and 3. The same similarities and dissimilarities are present at the level of the converters and electrical protections of each propulsion chain. These electrical protections ensure a protective role against certain electrical faults: short circuit between wires, between phases or between phases and ground. These electrical protections are known as: fuse, pyrofuse, circuit breaker, pyrotechnic circuit breaker, etc. With the exception of the fuse, these components are completely or partially controlled and depend on another element which will detect these short circuit faults.In most cases, these electrical protections combine an element that ensures detection and another that controls an element that cuts off the electrical fault. More generally, an electrical protection is the combination of two switches in series combining a double property: active component and passive component. Such electrical protection serves to protect the propulsion chain from the effects of the failure of an element of an electrical path, so as to locally circumscribe the electrical failure and allow the other electrical paths and elements to be maintained in nominal operation, and therefore to make them independent of the electrical failure and the affected path(s).

[0045] Thus, for an electrical fault originating from a source that may be alternating current or direct current, we will seek to isolate it from the consumer(s). For an electrical fault originating from a distribution element (HVDC or HVAC bus bar), we will seek to isolate it from the consumer(s) as well as from the source to prevent propagation to other electrical paths. For an electrical fault originating from an energy transformation element (AC / DC converter, DC / AC converter, etc.), we will seek to isolate it from the source, the distribution element as well as the downstream consumer(s).

[0046] Any electrical failure of the short circuit type must be able to be contained by isolating the other elements of the electrical circuit from the effects of this failure. Thus, each electrical protection must be independent of the causes it is supposed to cover, that is to say that any cause of failure leading to a short circuit must be independent of the electrical protection against short circuits.

[0047] It should be noted that these electrical protections are also capable of mitigating in the same way other risks than short-circuit risks, such as overvoltage, overtemperature or thermal runaway of electrical origin (battery) which must also be controlled at the level of an electric or hybrid propulsion system.

[0048] Between the two HVDC buses (HVDC bus 1, HVDC bus 2) is mounted a "Cross bar contactor" type bus electrical protection. This bus electrical protection consists of the series assembly of two types of elementary electrical protection: one controlled, such as a contactor (controlled on opening for example according to an overcurrent), and the other non-controlled, such as a circuit breaker (in English "breaker"), a pyrotechnic fuse (in English "pyrofuse"), a pyrotechnic circuit breaker (in English "pyroswitch"). These two protections are by nature dissimilar, each of them opening on very specific conditions, in redundancy or complementary.

[0049] Depending on the requirements, this electrical bus protection can be installed or not. If it is installed, the contactor is generally kept open, except in the event of a fault, and the circuit breaker is generally kept closed in the nominal position (the "cross bar contactor" must be open in the nominal case to maintain the independence of the two channels). The contactor (the controlled element) of the electrical protection can be made to close, following very specific phases of operation on the ground or in flight, to recharge one source with another for example, or in the event of a fault.During certain failures, rather than using the non-failing power paths at their maximum performance, it may be particularly advantageous to restore other paths and distribute the power over a number of paths, which is doubly advantageous because it avoids operating at maximum power some paths, which reduces the risk of failure and it allows to keep some paths redundant and therefore to maintain the system in a more fault-tolerant state.

[0050] From a safety point of view, the dependency between the two HVDC buses is only acceptable if it is possible to isolate one HVDC bus from the other again when one of the buses fails. The implementation may lead to implementing several electrical elements in order to be sure of being able to make the two buses independent again, by opening the dependency link, if one of the two buses were, for example, short-circuited. It should be noted that there are several possible combinations of sharing, depending on whether the bus power supply is simplex, duplex, or more. For example, in an architectural variant, it is possible to envisage that HVDC bus 1 is supplied in simplex only by source 2, i.e. without source 1, which would then not be installed.In this case, there would therefore really only be two energy sources, source 2 and source 3, i.e. a minimum cut of order 2 for the loss of availability of the sources, but with an appreciable gain on the mass balance compared to the minimum cut of order 3 relating to the loss of availability of the sources with the architecture of figure 1. The notion of minimum cut of order n must be understood as the number n of conditions necessary to lead to the loss of the aircraft in the sense of the fault tree (also called breakdown tree or fault tree) associated with the propulsion chains.

[0051] To preserve the principle of independence HVDC busl # HVDC bus2 optimally between the two buses, it is appropriate to specify that at least one power path of HVDC bus 1 is dissimilar to at least one power path of HVDC bus 2, which can be represented as follows:

[0052] • [pathl or path2.1] # [path2.2 or path3].

[0053] For example:

[0054] • [Sourcel + Protection 1 + Converterl + HVDC Bus 1] # [Source3 + Protections + Converters + HVDC Bus2], [Source2 # [HVDC busl or HVDC bus2]], which allows: Source2.1=Source2.2, Protection2.1=Protection2.2=[Protectionl or Protections or neither], Converter2.1=Converter2.2=[Converterl or Converters or neither],

[0055] • [Source2.1 + Protection2.1 + Converter2.1 + HVDC Bus 1] # [Source2.2 + Protection2.2 + Converter2.2 + HVDC Bus2], [Source2 # [HVDC busl or HVDC bus2]], Source2 # [Sourcel or Sources], which allows: Protections Protections = [Protection 2.1 or Protection2.2 or neither], Converterl =Converter3=[Converter2.1 or Converter2.2 or neither], • [Sourcel + Protection 1 + Converterl + HVDC Bus 1] # [Source + Source?.2+ Protection?.2 + Converter?.2 + HVDC Bus2], [Source? # [HVDC busl or HVDC bus2]], which allows: Sourcel=Source3, Protections Protections = [Protection?.1 or not],

[0056] Converterl =Converter3=[Converter2.1 or not],

[0057] • [Sourcel + Protection 1 + Converterl + HVDC Bus 1] # [Source? + Source?. i+ Protection?. i + Converter?. i + HVDC Bus2], [Source? # [HVDC busl or HVDC bus2]], which allows: Sources Sources, Protections Protections, Converterl=Converter3,

[0058] Of course, it is essential that path 2.1 is electrically independent of path 2.2 and that the failure of the common point "Source 2" does not propagate to lead to the loss of HVDC busl and HVDC bus2. To do this, it is therefore necessary that: Source 2 # [HVDC busl or HVDC bus2].

[0059] This independence is found at the level of the electric motors which are dissimilar to each other and whose routing is also distinct. Thus, the motor is powered from both the HVDC bus and the HVDC bus2 through dissimilar converters and electrical protections. More precisely, the motor is powered from the HVDC bus by a path 1.1 through electrical protection 1 and converter 1.1 and from the HVDC bus2 by a path 2.1 through electrical protection 2 and converter 2.1, it being understood that protection 1 and protection 2 are dissimilar and converter 1.1 and converter 2.1 are also dissimilar. Similarly, the motor is powered from the HVDC bus by a path 2.2 through electrical protection 1 and converter 1.2 and from the HVDC bus2 by a path 2.1 through electrical protection 2 and converter 2.1, it being understood that protection 1 and protection 2 are dissimilar and converter 2.1 and converter 2.2 are also dissimilar.

[0060] In Figure 2, sources 2.1 and 2.2 no longer have a common origin and are therefore distinct, and the load routing is different. Thus, the motor 1 is supplied exclusively from the HVDC bus 1 by two redundant paths, one 1.1 through the electrical protection 1 and the converter 1.1 and the other 1.2 through the protection 1 and the converter 1.2, and the motor 2 from the HVDC bus 2 by also two redundant paths, one 2.1 through the protection 2 and the converter 2.1 and the other 2.2 through the protection 2 and the converter 2.2.

[0061] Figure 3 shows a different example of HVDC bus1 and HVDC bus2 power supply with four separate sources (load routing is absent). This architecture is significantly different from the previous one, in that there are two sources that are shared on each HVDC bus. But there are also two additional HVDC buses. This advantageously allows the loads to be routed as previously illustrated in Figures 1 and 2 so as to eliminate the minimum second-order fault cut that exists when there are only two buses.

[0062] To optimally preserve the principle of independence between the two buses: HVDC busl # HVDC bus4, it is necessary to specify that at least one power supply path of HVDC bus 1 is partially or totally dissimilar to at least one power supply path of HVDC bus 4, which is as follows:

[0063] • [path1 or path2] # [path3 or path4].

[0064] For example, among several possible distributions of dissimilarity on this architecture, at least the following minimal choice:

[0065] • [Sourcel + Protection 1 + Converterl + HVDC Bus 1] # [Source4 + Protection4 + Convert + HVDC Bus4], [Source2 # [HVDC busl or HVDC bus4]], [Source3 # [HVDC busl or HVDC bus4]], which allows: Sourcel =Source2, Protection l=Protection2, HVDC busl= HVDC bus2, Converterl =Converter2, Source3=Source4, Protections =Protection4, Converters =Converter4, HVDC bus3= HVDC bus4.

[0066] Another example of such a suitable distribution takes advantage of the dissimilarity which, depending on the case, may exist between sources 2 and 3 based on batteries and sources 1 and 4 which could be different from batteries.

[0067] The interest of adding in these two previous configurations an electrical bus protection (Protection 5 and Protection 6) between the HVDC1 and HVDC4 buses remains the same as for the first configuration. The cross contactor can serve as redundancy for the HVDC2 and HVDC3 buses to allow the HVDC1 bus to be connected to the HVDC 4 bus. The architecture of Figure 4 uses the principles of the previous one but allows the number of available sources to be reduced. In this configuration, the loss of the sources is a minimum cut of order 3. If the needs and the reliability / availability of the sources allow it, the number of sources could even be further reduced by removing, for example, Source or Source3. In this case, the loss of the sources would be a minimum cut of order 2, which is not prohibitive in itself.

[0068] Here again, to preserve the principle of independence (HVDC busl # HVDC bus4) optimally between the two buses, it is appropriate to specify that at least one power supply path of the HVDC busl is partially or totally dissimilar to at least one power supply path of the HVDC bus4, which is as follows:

[0069] • [pathl.l or path? or path3] # [pathl.2 or path3 or path?].

[0070] There are several possible distributions of dissimilarity on this architecture including the following which minimizes the number of dissimilar elements:

[0071] • [Source 1 + Sourcel.i + Protection li + Converterl.i + HVDC Bus 1] # [Source2 / 3 + Protection2 / 3 + Converter2 / 3 + HVDC Bus4], [Source? # [HVDC busl or HVDC bus4]], [Source3 # [HVDC busl or HVDC bus4]], which allows: Source? =Source3, Protection? = Protections, HVDC busl= HVDC bus2, Converter? =Converter3, Sourcel.l=Sourcel.2,

[0072] Protection 1.1= Protection 1.2, Converter 1.1 =Converter 1.2, HVDC bus3= HVDC bus4.

[0073] Of course, it is fundamental that path 1.1 is electrically independent of path 1.2 and that the failure of the common point of the common source does not propagate to lead to the loss of both HVDC busl and HVDC bus4. To do this, it is therefore necessary that: Source 1 # [HVDC busl or HVDC bus4].

[0074] As before, the benefit of adding bus electrical protection between the HVDC1 and HVDC4 buses remains the same as for previous architectures. The cross-contactor can serve as redundancy for the HVDC bus2 and HVDC bus3 to allow the HVDC bus1 to be connected to the HVDC bus4.

[0075] The architecture illustrated in Figure 5 represents a ring network with three distinct sources. In such a ring network architecture, the loads (the electric motors driving the propellers) are not directly connected to the HVDC buses but through so-called Reconfiguration modules arranged at the intersection of two adjacent HVDC buses of the ring and consisting of two bus electrical protections. Each of these two bus electrical protections consists of the series assembly of two types of elementary electrical protection (Protection_a and Protection_b on the one hand and Protection_c and Protection_d on the other hand) which are dissimilar by nature: one controlled, like a contactor, and the other uncontrolled, like a circuit breaker. These bus electrical protections are not necessarily all identical as illustrated and the dissimilarity of the modules as illustrated could be organized differently.

[0076] On such a three-source ring network, there are three load connection points (at the junction point between the two bus electrical protections) whereas on a four-source ring network as shown in Figure 6, there are four source connection points.

[0077] While in all previous configurations there were several power grids (2, 3, 4, ...) that were electrically independent HVDC buses, the ring network is the example of an implementation in which all sources and loads are connected to the same network. Such a network is organically like a spider web that offers important advantages for the fault tolerance of the different network actors.

[0078] To respect the principle of independence which guides the invention, it is appropriate that the dysfunctional behavior of a network object, source, converter, bus, or load, does not compromise the operation of the other objects, whatever the failure cases, that is to say that these objects are autonomous from the point of view of their operation. In other words, at least two families of power supply paths must be independent (including systematic failures), that is to say that there must always be at least two families of sources, converters, buses, and loads which must be independent.

[0079] Since we want two independent groups of propellants (Groupel # Group2), this implies that there is at least one network independent of another, that is HVDC bus_i # HVDC bus_others. Thus, if there were to be a need for independence of order 3 on an architecture (Groupel#Groupe2#Groupe3), there would have to be at least two distinct paths partially or totally dissimilar to each other and to the others, HVDC bus_i # HVDC bus_j # HVDC bus_others. Similarly, if there were a need for independence of order n, there would have to be at least n-1 paths partially or totally dissimilar to each other and to the last ones.

[0080] In our three-bus ring network configuration, with a need for second-order independence (Group#Group2), it is therefore appropriate to have at least one bus partially or totally dissimilar to the other two, while on a four-bus architecture, it is appropriate to have at least one bus partially or totally dissimilar to the other three. As in the previous architectures, there are several ways to distribute the dissimilarity. In particular, when there is an even number of buses, as illustrated in Figure 6, equipartition of the dissimilarity is a solution that from an industrial point of view offers advantages in terms of production volume, stocks, feedback, etc.

[0081] It should be noted, however, that, as with all examples of propulsion architectures presented in this invention, other distribution choices may be justified depending, for example, on: the reliability of the diversified technological solutions, the aircraft and its ability to install pathways that do not corrupt the expected independence by common causes of failure due to the areas of the aircraft crossed by the pathways, or other threats such as, for example, high-energy debris.

[0082] Some examples of dissimilarities are now described for generators, converters, motors and electrical protections. These examples are only illustrative and do not limit the invention.

[0083] For a propulsion system for generating energy, at least two different voltage generators can be connected in parallel: one generator generates electricity using a rotating machine and the other generator generates electricity electrochemically. For the converters present in the propulsion system, the dissimilarity can be hardware or software. For example, one converter can have a digital control architecture while another converter has an analog control architecture. This makes it possible, in particular, to reduce its vulnerability to cybersecurity attacks (possible introduction on the digital network, but not on the analog network), and to lightning strikes (lightning can cause the digital network, which is more sensitive, to malfunction, and therefore the conversion function can be maintained thanks to the analog control network).

[0084] Regarding the motors present in the propulsion system, different motor topologies can be used. For example, one motor can be a permanent magnet synchronous machine and another an asynchronous machine. This helps to limit problems related to the nature of the materials used for the magnets.

[0085] Finally, for protection systems, they can be remotely controlled or triggered autonomously. Electromechanical protection (circuit breaker, fuse or pyrofuse) or electronic protection (solid-state power controller "SSPC") can also be used.

Claims

Claims

1. Aircraft electric or hybrid propulsion architecture comprising at least two propulsion chains, each propulsion chain comprising at least one electric motor (Motor1, Motor2) powered from at least two energy sources (Source1, Source2, Source3, Source4) of the propulsion architecture through at least two energy supply paths, each energy supply path comprising at least one energy converter (Converter1, Converter2) and an electrical protection (Protection 1, Protection2) delivering a direct voltage for an HVDC bus (HVDC bus1, HVDC bus2, HVDC bus3, HVDC bus4), each HVDC bus distributing this direct voltage to at least one electric motor (Motor1, Motor2) through at least one of said energy converters and one of said electrical protections, the propulsion architecture being characterized in that the energy source (Source1), the energy converter (Converter1),the electrical protection (Protection 1) and the HVDC bus (HVDC busl) of a power supply path are each dissimilar respectively to the power source (Source4), the power converter (Converter4), the electrical protection (Protection4) and the HVDC bus (HVDC bus4) of at least one other power supply path.,

2. Architecture according to claim 1, in which the electric motors (Motor1, Motor2) of the at least two propulsion chains are dissimilar.

3. Architecture according to any one of claims 1 or 2, further comprising an electrical bus protection (Protections - Protections) mounted between two dissimilar HVDC buses.

4. Architecture according to claim 3, in which the bus electrical protection comprises a series assembly of a controlled elementary electrical protection, preferably comprising a contactor, and basic non-controlled electrical protection, preferably comprising a circuit breaker.

5. Architecture according to any one of claims 1 to 4, the architecture being configured to be applied to a three-bus HVDC annular power distribution network, in which at least one HVDC bus (HVDC bus3) is partially or totally dissimilar to the other two (HVDC busl - HVDC bus2).

6. Architecture according to any one of claims 1 to 4, the architecture being configured to be applied to a four-bus HVDC annular power distribution network, in which at least one HVDC bus (HVDC bus3 - HVDC bus4) is partially or totally dissimilar to the other three (HVDC busl - HVDC bus2).

7. Architecture according to claim 5 or claim 6, in which two adjacent HVDC buses of the power distribution network are connected together by a series assembly of two electrical bus protections (a, b; c, d).

8. Architecture according to claim 7, wherein each of said two bus electrical protections (a, b; c, d) comprises two dissimilar elementary electrical protections, preferably a controlled elementary electrical protection and a non-controlled elementary electrical protection.

9. Electric or hybrid aircraft comprising an electric or hybrid propulsion architecture according to any one of claims 1 to 8.

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