Electrical fault isolation in aircraft power distribution networks.

Abstract

The power distribution network (306) of the aircraft power system (300) is operated in at least one normal operating mode such that it provides load balancing for electrical loads (AA, BB, CC, DD) across the power sources (A, B, C, D), and the power distribution network (306) is operated in at least one electrical fault mitigation operating mode that provides electrical fault isolation such that, in the event of an electrical fault, a network portion of the power distribution network (306) having an electrical fault is isolated from at least one other network portion of the power distribution network.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention generally relates to an electrical power system for an aircraft, and to an aircraft comprising such an electrical power system. For example, the aircraft may be a canard-type aircraft with multiple lift / thrust units distributed along the front or canard and along the rear or main wings. The electrical power system comprises multiple electrical loads, such as multiple lift / thrust units and / or multiple flap actuators, multiple electrical power sources, such as multiple storage or battery units, and a power distribution network configured to connect the electrical power sources to the electrical loads, such that each electrical load can be driven by at least one associated electrical power source via at least one associated power lane of the power distribution network. The present invention further relates to a method for operating an electrical power system of an aircraft. [background] Aircraft may be broadly classified as fixed-wing and rotary-wing. Fixed-wing aircraft typically include a number of control surfaces that, when controllably positioned, guide the movement of the aircraft from one destination to another. The number and type of control surfaces included in an aircraft may vary. Primary control surfaces are typically those used to control the motion of the aircraft about the pitch, yaw, and roll axes. Secondary control surfaces are typically those used to affect the lift or drag (or both) of the aircraft. Primary control surfaces typically include elevators, ailerons, and rudders, and secondary control surfaces typically include a number of flaps, slats, speed brakes, and spoilers.

[0002] Rotorcraft such as helicopters typically do not have rotors separate from the airfoils that generate lift, but the airfoils that make up the rotors provide cyclic control for pitch and roll, and collective control for lift.

[0003] Furthermore, aircraft are known that have vertical take-off and landing capabilities based on propulsion engines that are mounted for rotation about the lateral or pitch axis of the aircraft. The propulsion engines are controllably movable between a cruise flight position and a take-off / landing position. In the cruise position, the engines provide forward thrust and the movement of the aircraft through the air is controlled by suitable control surfaces. In the take-off / landing position, the propulsion engines are angled downwards to enable vertical take-off or landing based on the thrust provided by the engines.

[0004] Such an aircraft type, with vertical take-off and landing capability and equipped with electric ducted propellers as propulsion engines, has been proposed by the applicant Lilium eAircraft GmbH through US2016 / 0023754A1 and US2016 / 0311522A1 and further publications of the same patent family. The applicant has in turn developed an aircraft called Lilium Jet, which is a canard-type aircraft equipped with left forward engines, right forward engines, left aft engines and right aft engines in the form of electric ducted propellers, which are mounted on the left and right canards forward of the canard-type aircraft and on the respective flaps of the left and right aft wings or main wings. The first test flight of this Lilium Jet was carried out on October 1, 2019.

[0005] Another type of aircraft with vertical take-off and landing capability and operated electrically is known from US2020 / 0010187A1. The aircraft comprises a number of propulsion assemblies each comprising an electric motor with two independent windings, whereby the electric motor is dual-fed. A number of battery units are associated with the electric motors in pairs, such that a first winding of each electric motor can be driven on one of the battery units and a second winding of each electric motor can be driven on another battery unit. Various power system architectures aimed at achieving fault tolerance are disclosed. According to a first embodiment, six electric motors and six battery units are arranged in a ring architecture, such that each battery unit supplies power to two electric motors, and each electric motor receives power from two battery units. According to a second embodiment, six electric motors and four battery units are arranged in a doublet architecture, such that each battery unit supplies power to three electric motors, and each electric motor receives power from two battery units. According to a third embodiment, the six electric motors and the six storage battery units are arranged in a hexagram architecture, such that each storage battery unit supplies power to two motors and each electric motor receives power from two battery units. According to a fourth embodiment, the six electric motors and the four storage battery units are arranged in a star architecture, such that each storage battery unit supplies power to three electric motors and each electric motor receives power from two battery units. According to a fifth embodiment, the six electric motors and the four storage battery units are arranged in a star architecture, such that each storage battery unit supplies power to three electric motors and each electric motor receives power from two battery units. According to a sixth embodiment, the six electric motors and the four storage battery units are arranged in a mesh architecture, such that each storage battery unit supplies power to three electric motors and each electric motor receives power from two battery units. According to the mesh architecture, a first set of battery units drives both windings of a commonly associated first electric motor, and a second set of battery units drives both windings of a commonly associated second electric motor.

[0006] For any such type of aircraft, and any other type of aircraft, resilience to mechanical failure is one of the most important aspects, and this also pertains greatly to the aircraft's power distribution network.

[0007] All power distribution networks for safety-critical applications such as aircraft have an inherent contradiction: isolation prevents fault propagation, while integration allows efficient load balancing across power sources. Typical approaches include isolated "power lanes" that contain electrical faults in one lane, but do not benefit from load balancing across power sources. Any approach that uses integration is considered inherently unsafe, since electrical faults will propagate throughout the network, causing temporary or constant outages. Therefore, typical power distribution networks for safety-critical applications strictly follow the isolation direction, and therefore miss the opportunity to gain the benefits of integration.

[0008] According to conventional approaches, some integration may be introduced in response to the occurrence of a fault to compensate for this fault. For example, conventional aircraft electrical systems may use electromechanical relays to provide integration, but with reduced safety tolerances and therefore only following system failure to develop.

[0009] It is known to use solid state and electromechanical switching devices in power distribution networks to enable and inhibit the transmission of power between relevant parts of the power distribution network depending on the current conditions and needs.

[0010] Additionally, it is known to use solid-state and electromechanical circuit protection devices (SPDs), such as solid-state and electromechanical circuit breakers, in power distribution networks to protect electrical wiring and downstream electrical loads when a short circuit occurs. It is also known to use so-called "solid-state power controllers" or "semiconductor power controllers," commonly referred to as "SSPCs," as circuit protection devices in power distribution networks, including aircraft power distribution networks, to replace conventional electromechanical circuit breakers or even "older style" fuses.

[0011] A solid-state power controller (SSPC) is a circuit protection device, such as a fuse or another type of circuit breaker, and therefore aims to protect electrical wiring and downstream electrical loads when a short circuit occurs. Compared to traditional electromechanical devices (fuses and circuit breakers), SSPCs have a number of advantages, such as faster opening when a short circuit occurs, lighter weight and smaller volume, software resettable (no need to manually contact or carry spare fuses for maintenance), very flexible in terms of current and voltage trip ratings, self-testing to avoid potential failures, recording data on the health of the electrical system, and performing additional functions including those of a switching device. To this end, the SSPC includes a microcontroller, a communication interface for data communication with a higher-level control entity, one or more load channels with a monitoring function for monitoring at least one electrical condition of each load channel, and a solid-state switch in each load channel, such as at least one metal oxide field effect transistor (MOSFET), at least one bipolar transistor (BJT), silicon controlled rectifier (SCR), and a triac. The microcontroller monitors at least one electrical condition including the current flowing through each load channel to each load and commands the solid-state switch to open when an electrical trip condition occurs, such as when the detected current exceeds a certain threshold. Multiple electrical trip conditions may be set to address different types of electrical faults.

[0012] Various SSPC distribution architectures are known, such as hierarchical architectures optimized for centralized control of a larger number of SSPCs (e.g., >40 SPPs) from a vehicle management system (VMS) having at least one electrical system controller (ESC). Control is achieved via solid-state power managers (SSPMs), which are grouped with associated SSPCs in secondary power distribution units (SPDUs). Similarly known, less hierarchical architectures are typically used for centralized control of a smaller number of SSPCs (e.g., <40 SPPs) from a vehicle management system (VMS). The SSPCs are grouped in a primary power distribution unit (PPDU). The SSPC distribution architecture may provide redundancy by having at least two electrical system controllers (ESCs) in the vehicle management system (VMS) and at least two solid-state power managers (SSPMs) in each secondary power distribution unit (SPDU).

[0013] For an electric aircraft power system having multiple power sources in the form of accumulators or accumulator units for powering various electrical loads or aircraft devices, the uneven discharge of these power sources is undesirable and can cause problems. In addition, the uneven discharge of the accumulators can adversely affect the range. To achieve high aircraft performance, at least in certain situations, such as flight maneuvers that require increased drive power for the lift / thrust units, it is preferable if each of the electrical loads or aircraft devices, such as each of the multiple lift / thrust units, can be driven by multiple independent power sources.

[0014] In view of the above, it is an object of the present invention to provide an electrical power system for an aircraft, and a corresponding method of operation, that makes it possible to achieve sufficient resilience against electrical faults in an efficient manner.

[0015] It is a further object of the present invention to provide an electrical power system and corresponding method of operation for an aircraft that enables high aircraft performance for flight maneuvers that require increased propulsion power along with achievable range.

[0016] A further object of the invention is to provide an electrical power system for an aircraft, and a corresponding method of operation, making it possible to achieve a uniform discharge of an electrical power source in the form of a battery or battery unit. [Summary of the Invention] To achieve at least one of these objectives, the present invention provides an electrical power system for an aircraft comprising a plurality of electrical loads, a plurality of electrical power sources, and a power distribution network configured to connect the electrical power sources with the electrical loads such that each electrical load can be driven by at least one associated electrical power source via at least one associated power lane of the power distribution network.

[0017] The power distribution network includes at least one of a circuit protection device and a circuit switching device having a plurality of switchable or interruptable power links, each power link having two connection ports, each power link configured to connect the connection ports in a first operating mode to transmit power from a driving power lane or driving power lane portion connected to one of the connection ports to a driven power lane or driven power lane portion connected to another one of the connection ports, and configured to interrupt the connection between the connection ports in a second operating mode to prevent transmission of power between the driving power lane or driving power lane portion and the driven power lane or driven power lane portion.

[0018] The power distribution network is configured to operate in at least one normal operating mode and at least one electrical fault mitigation operating mode.

[0019] The power distribution network, in a normal operating mode, provides load balancing across the power sources such that at least one power source group of the plurality of power sources commonly powers at least one associated electrical load group of the plurality of electrical loads via an associated power lane or power lane section therewith and at least one power link associated therewith that is in a first operating mode.

[0020] The power distribution network provides electrical fault isolation in an electrical fault mitigation mode such that a network portion of the power distribution network having an electrical fault is isolated from at least one other network portion of the power distribution network by at least one power link that is in a second operating mode.

[0021] The proposed power system makes it possible to combine the advantages of an integrated electrical network with those of an isolated electrical network. In a normal operating mode, as envisaged in normal operation of the aircraft, the integration between the power lanes of the network allows efficient load balancing across the power sources. In the event of an electrical fault, the power distribution network assumes an electrical fault mitigation operating mode, which results in a separation between the involved power lanes and therewith in the isolation of the electrical fault.

[0022] While such integration would be considered unsafe for safety-critical applications such as flight according to conventional approaches, according to the present invention an integrated electrical network may be realized for normal operation of the aircraft, with all the advantages that result from integration.

[0023] The power system of the present invention is therefore substantially distinct from conventional power distribution networks of aircraft, which, during normal operation of the aircraft, comprise given electrical loads that are irrevocably assigned to given power sources through the use of isolated power lanes. This assignment results in uneven power demands on the power sources, which is not optimal, particularly for battery electric vehicle / electric aircraft applications. Then, following a power lane failure, the separation must be interrupted by introducing a degree of integration to provide continuity of supply to the electrical loads. This loss of separation results in a reduction of the safety margin.

[0024] According to the present invention, a completely different approach is pursued: several or all power sources and several or all electrical loads are integrated or connected together in normal operation, which is optimal for load balancing across the power sources and with it for a uniform power demand on the power sources. The accumulators acting as power sources are discharged evenly. Any electrical faults are safely isolated before they can propagate, and then after the faults have disappeared, the integration can be safely re-established and the network returns to normal operation. This electrical fault isolation can be done in a very fast manner by using suitable technical elements such as solid-state power controllers (SSPCs), which may be used as a first stage immediate isolation according to the present invention, not for the purpose of isolating the failed power source or the failed load, but for the purpose of intentionally introducing isolation to mitigate the electrical fault.

[0025] In comparison to standard integrated networks, fault isolation by intentional isolation makes it easier and faster to extinguish the fault, since it is easier to extinguish a fault in an isolated or partially isolated power distribution network when only one or a limited number of power sources feed the fault, as opposed to multiple sources, which would be the case in a standard integrated network.

[0026] The power distribution network may be configured to provide partial load balancing across the power sources with respect to associated electrical loads in a time-varying manner according to a number of different partial load balancing modes continuously adopted by the power distribution network, where a number of power source groups of said number of power sources and a number of associated electrical load groups of said number of electrical loads are provided, whereby each one or more groups of power sources active at a given time are continuously, preferably periodically, varied to commonly drive at least one associated electrical load group. However, in the context of the present disclosure, permanent, continuous load balancing across the power sources in a normal operating mode is more preferred.

[0027] Advantageously, the power distribution network may be configured to support an electrical fault mitigation mode of operation such that an electrical fault occurring in a power source of the power source group can be isolated from at least one other power source of the power source group and from at least one electrical load of the electrical load group, and such that an electrical fault occurring in an electrical load of the electrical load group can be isolated from at least one power source of the power source group and at least one other electrical load of the electrical load group, thereby enabling at least one power source belonging to the power source group to be unaffected by the electrical fault and to drive at least one electrical load belonging to the electrical load group, the isolation of the electrical fault being achieved by at least one power link changing its operating mode from a first operating mode to a second operating mode.

[0028] If desired, a plurality of electrical loads of the same type may form an electrical load group. Alternatively, a plurality of electrical loads of different types may form an electrical load group. A plurality of different groups of such types may be provided.

[0029] According to a preferred embodiment, the power distribution network is configured to provide load balancing across all power sources in a normal operation mode such that all power sources of the plurality of power sources commonly drive all electrical loads of the plurality of electrical loads via their respective power lanes or power lane portions and respective power links in a first operation mode, and the power distribution network is configured to provide an electrical fault mitigation operation mode in such a way that an electrical fault occurring at a power source or at an electrical load can be isolated such that a plurality or all power sources not affected by the electrical fault can drive a plurality or all electrical loads not affected by the electrical fault.

[0030] There are no limitations regarding the architecture and structure of the power distribution network and the arrangement of its power lanes. According to a preferred approach, the power distribution network may comprise a plurality of first-type power lanes, each first-type power lane having at least one associated power source associated therewith that is not associated with another first-type power lane, and each first-type power lane having at least one associated electric load that is not associated with another first-type power lane, such that at least one associated power source is connected or connectable to at least one associated electric load via the respective first-type power lane, thereby allowing at least one power source to drive at least one electric load via the respective first-type power lane without necessarily driving via another first-type power lane. According to the conventional approach mentioned above, these first-type power lanes would be isolated from each other at all times or during normal operation of the aircraft.

[0031] The integration between the multiple first type power lanes may be realized by another type of power lane provided in addition to the first type power lanes. In this respect, it is proposed that the multiple first type power lanes are connected or connectable via a connecting lane device of the power distribution network, the connecting lane device including one or more second type power lanes, and transmitting power between these first type power lanes via at least one second type power lane to enable load balancing for electrical loads associated with these first type power lanes across power sources associated with at least one first type power lane group or associated with all first type power lanes.

[0032] The connection lane device may advantageously include at least one connection lane associated with at least two, preferably at least three, first type power lanes, which are connected or connectable to the connection lane via respective second type power lanes associated with each of the first type power lanes.

[0033] The connection lane device may preferably include one or more second-type power lanes, each second-type power lane having two associated first-type power lanes such that two first-type power lanes are connected or connectable via the second-type power lanes, thereby enabling load balancing for electrical loads associated with the two first-type power lanes across power sources associated with the two first-type power lanes by transmitting power between the two first-type power lanes via the second-type power lanes. In this regard, it is preferable that the transmission of power between two first-type power lanes via a second-type power lane does not necessarily involve the transmission of power via another second-type power lane.

[0034] The first and second type power lanes may be arranged in a variety of different ways or according to a variety of topologies. In general, where a power distribution network comprises two, three, or more second type power lanes associated with a plurality of first type power lanes in such a manner, it will be suitable that each of said plurality of first type power lanes is connected or connectable to at least one other of the first type power lanes via a respective second type power lane.

[0035] In this regard, according to a first implementation approach, it is further proposed that each of the plurality of first type power lanes, or a sub-group of the plurality of first type power lanes, is connected or connectable to two other of the plurality of first type power lanes, or a sub-group of the first type power lanes, via respective second type power lanes, thereby enabling load balancing across electrical loads in a ring topology.

[0036] According to a second implementation approach implemented additionally or alternatively, it is proposed that two power lanes of the plurality of first-type power lanes or a subgroup of the plurality of first-type power lanes are connected or connectable to only one other power lane of the plurality of first-type power lanes or a subgroup of the plurality of first-type power lanes or to each other via a respective second-type power lane, and each other power lane of the plurality of first-type power lanes or the subgroup of the plurality of first-type power lanes is connected or connectable to two other power lanes of the plurality of first-type power lanes or a subgroup of the plurality of first-type power lanes via a respective second-type power lane when one or more such other power lanes are provided, thereby enabling load balancing among electric loads in a line topology along all these second-type power lanes. This includes the case where only two first-type power lanes are provided, which are connected or connectable to each other via a second-type power lane.

[0037] According to a third implementation approach, as an alternative to the first and second implementation approaches or implemented together with one or both of the first and second implementation approaches, it is proposed that one power lane of the plurality of first type power lanes, or a subgroup of the plurality of first type power lanes, is connected or connectable via a respective second type power lane with at least three other power lanes of the plurality of first type power lanes, or a subgroup of the plurality of first type power lanes, thereby enabling load balancing across electrical loads in a star topology. Each of these at least three other power lanes may be a power lane that is the starting point of a power lane line including a plurality of power lanes, according to the above-mentioned line topology, if necessary.

[0038] According to a preferred variant of the third implementation approach, it is proposed that the connection lanes of the connection lane device are connected or connectable via respective second type power lanes with at least three power lanes of said plurality of first type power lanes or a subgroup of said plurality of first type power lanes, thereby enabling load balancing across the electrical loads in a star topology, each of these at least three other power lanes being, again, if necessary, a power lane starting point of a power lane line comprising a plurality of power lanes according to the above-mentioned line topology.

[0039] The third implementation approach variant has the great advantage that the connecting lanes instead of the first type power lanes act as a hub or center of the star topology, so that it is highly unlikely that this hub or center can be directly affected by an electrical fault. This hub or center may be isolated by the respective second type power links from any of the associated first type power lanes, and thus from any electrical fault that may occur therein. This makes it possible to maintain partial load balancing even in the event of an electrical fault that directly affects any one of the first type power lanes.

[0040] Preferably, each of the first type power lanes comprises a first type power link which, in its first operating mode, enables the transmission of power from the at least one associated power source to the at least one associated electrical load via the first type power link and, in its second operating mode, prevents the transmission of power from the at least one associated power source to the at least one associated electrical load via the first type power link.

[0041] Such first type power links essentially correspond to conventional circuit breakers, such as fuses, or electromechanical or solid-state circuit protection devices that serve to protect electrical wiring and downstream electrical loads when a short circuit occurs. Each first type power link may therefore be configured to change its operating mode from a first operating mode to a second operating mode within a trip time interval of a first order of magnitude in response to at least one predefined or predefinable electrical trip condition indicative of an electrical fault.

[0042] The first type of power link may be configured to trip according to one or more predefined electrical trip conditions. Any suitable electrical trip conditions known in the art may be implemented. This implementation may be implemented in hardware such as conventional fuses and circuit breakers that have predefined electrical trip conditions, such as a set of predefined trip curves implemented by a manufacturer, such that when commanding a device to change the trip curve, one would have to change the part number of the device.

[0043] For example, the at least one predetermined electrical trip condition may include at least one of: i) a current transmitted through the first type of power link that exceeds a predetermined current trip threshold; ii) an i2t quantity representing electrical energy dissipated through the first type of power link within a predetermined reference time interval that exceeds a predetermined electrical i2t trip threshold.

[0044] According to a preferred implementation, each power link of the first type is provided by an electromechanical or solid-state circuit protection device of the power distribution network, for example by an electromechanical or solid-state circuit breaker. Solid-state devices are preferred. It is not excluded that the power links of the first type are realized by one or more solid-state power controllers (SSPCs) of the power distribution network.

[0045] In order to enable the power distribution network to be able to undertake configurations that provide integration and configurations that provide separation, second type power lanes are proposed, each comprising a second type power link, which in its first operating mode allows the transmission of power between the first type power lanes via this second type power link and which in its second operating mode prevents the transmission of power between the first type power lanes via this second type power link.

[0046] Each power link of the second type may be configured to change its operation mode from the first operation mode to the second operation mode within a trip time interval of the second order of magnitude in response to at least one preset or pre-settable electrical trip condition indicative of an electrical fault. In order to enable the power distribution network to respond fast enough to the electrical fault to introduce the required isolation for fault isolation, it is proposed that the trip time interval of the first order of magnitude of the power link of the first type is significantly greater than the trip time interval of the second order of magnitude of the power link of the second type. Therewith, it may be realized that only one or more power links of the second type trip and switch to the second operation mode, but within a time interval before the tripping of one or more power links of the second type, none of the power links of the first type trip and switch to the second operation mode. Only after the achievement of fault isolation, typically only one specific power link of the first type that is still affected by the electrical fault after isolation or partial isolation will trip.

[0047] Various suitable electrical trip conditions known in the art may be implemented by corresponding configurations of one or more power links of the second type. In this respect, it is proposed that the at least one predetermined electrical trip condition comprises at least one of: i) a current transmitted through the power link of the second type exceeding a predetermined current trip threshold, ii) an i2t quantity representing electrical energy dissipated through the power link of the second type within a predetermined reference time interval exceeding a predetermined electrical i2t trip threshold, and iii) thermal energy determined by the controller of the power distribution network based on a thermal model to have been stored in an associated component of the power system within the predetermined reference time interval exceeding a predetermined thermal energy trip threshold.

[0048] To be sufficiently fast, each second type power link should typically be provided by an associated solid-state circuit protection device of the power distribution network, such as a solid-state circuit breaker. Thus, sufficiently fast conventional solid-state circuit breakers may be used to implement the invention with respect to the second type power links to achieve isolation between the first type power lanes before any of the first type power links trip and switch to the second mode of operation.

[0049] However, according to a particular preferred approach, each second type of power link is provided by an associated solid-state power controller of the power distribution network, comprising a microcontroller, at least one load channel forming the second type of power link, and at least one solid-state switch included in the load channel and operable under the control of the microcontroller, the microcontroller configured to switch the solid-state switch between a conducting state corresponding to a first mode of operation of the second type of power link and a non-conducting state corresponding to a second mode of operation of the second type of power link, and configured to monitor a current electrical state of at least one of the load channels and to respond to the occurrence of an electrical trip condition by switching the solid-state switch from a conducting state to a non-conducting state. By implementing the second type of power link using one or more solid-state power controllers, significant advantages are achieved.

[0050] According to a particularly preferred embodiment, which may be realized in a particularly preferred manner by using solid-state power controllers as power links, the power distribution network is configured, when switching from a normal operation mode to an electrical fault mitigation mode in response to the occurrence of an electrical fault, to provide electrical fault isolation by subsequently undertaking at least three fault isolation stages, a first fault isolation stage providing isolation of power lanes from each other by at least one power link switching from its first operation mode to its second operation mode, a subsequent second fault isolation stage providing fault isolation in power lanes still affected by the electrical fault by a power link switching from its first operation mode to its second operation mode, and a subsequent third fault isolation stage providing partial restoration of load balancing for electrical loads not affected by the electrical fault across power sources not affected by the electrical fault by at least one power link switching from its second operation mode to its first operation mode and isolated from the electrical fault by at least one other power link that is in the second operation mode.

[0051] The first fault isolation stage may preferably provide isolation of the first type power lanes from each other by at least one second type power link included in each second type power lane and switching from its first operating mode to its second operating mode.

[0052] The second fault isolation stage may preferably effect fault isolation within a first type of power lane by a first type of power link included in the first type of power lane switching from its first operating mode to its second operating mode.

[0053] The third fault isolation stage may preferably provide partial restoration of load sharing for electrical loads not affected by the electrical fault across power sources not affected by the electrical fault by at least one second type power link included in each second type power lane and switched from its second operating mode to its first operating mode and isolated from the electrical fault by at least one other power link that continues to be in the second operating mode.

[0054] The third fault isolation stage is particularly beneficial because multiple second type power links, as well as one or more power links that were not directly connected to the electrical fault but only via one or more other second type power links, may have tripped and switched to the second operating mode. After fault isolation is achieved, such second type power links may be switched back to their first operating mode to reintroduce partial integration and partially restore load balancing across the power sources.

[0055] Thus, the at least one other power link that continues to be in the second operating mode and isolates the one or more second type power links from the electrical fault may include at least one second type power link included in a respective second type power lane, however, it is also possible that the at least one other power link that continues to be in the second operating mode and isolates the one or more second type power links from the electrical fault may include a first type power link that has switched from its first operating mode to its second operating mode following the second fault isolation phase.

[0056] The power distribution network may preferably include at least one controller configured to control partial restoration of load balancing across the power sources according to the third fault isolation stage by determining, based on at least one of the measured electrical quantity, the measured electrical quantities, and the current operating modes of the one or more power links, which of the plurality of second type power links that have switched from their first operating mode to their second operating mode according to the first fault isolation stage is isolated from the electrical fault by at least one other power link that is in the second operating mode and therefore should switch back to the first operating mode for partial restoration of load balancing.

[0057] In this respect, local control of partial restoration of load balancing may be provided. For example, in the case where the second type of power link is formed by the load channels of one or more solid-state power controllers of the power distribution network, the microcontroller of each respective solid-state power controller may be preferably configured to monitor the current electrical state of at least one of the respective load channels whose solid-state switches are in a non-conducting state, preferably the current electrical state of at least one of each on both sides of the load channel of the solid-state switch, to determine whether the load channel should be isolated from the electrical fault by at least one other power link that is in the second operating mode and therefore switched back to a conducting state partially restoring the load balancing, thereby controlling the partial restoration of the load balancing across the power sources by the third fault isolation stage.

[0058] According to another preferred approach, at least one upper controller of the power distribution network, for example a solid-state power manager (SSPM) of a so-called secondary power distribution unit (SPDU) or an electrical system controller (ESC) of a vehicle management computer (VMC) when implementing a corresponding SSPC distribution architecture, or a flight control computer system of an aircraft, may be configured to control the partial restoration of load sharing across the power sources by a third fault isolation stage by being configured to receive status data or status signals from one or more circuit protection devices and / or one or more solid-state power controllers, and / or by being configured to monitor a current electrical status of a power lane or power lane section of the power distribution network, and by being configured to determine based on one or both of these status data and these monitoring which of a plurality of second type power links currently in the second operating mode should be commanded to switch back to the first operating mode for partial restoration of load sharing.

[0059] To achieve at least one of the above-mentioned objects, the present invention further provides a method of operating an aircraft power system comprising a plurality of electrical loads, a plurality of electrical power sources, and a power distribution network configured to connect the electrical power sources with the electrical loads such that each electrical load can be driven by the at least one associated electrical power source via at least one associated power lane of the power distribution network, the power distribution network comprising a plurality of switchable or interruptable power links, each provided within a respective power lane of the power distribution network, for enabling transmission of electrical power via the respective power lane in a first operating mode of the power links and for preventing transmission of electrical power via the respective power lane in a second operating mode of the power links.

[0060] The method includes operating a power distribution network in at least one normal operating mode that provides load balancing across the power sources such that at least one group of power sources of the plurality of power sources commonly power at least one associated group of electrical loads of the plurality of electrical loads via respective power lanes, including at least one power lane having a power link that is in a first operating mode.

[0061] The method further includes operating the power distribution network in at least one electrical fault mitigation operating mode that results in electrical fault isolation such that a network portion of the power distribution network having an electrical fault is isolated from at least one other network portion of the power distribution network by at least one power link that is in the second operating mode.

[0062] The method of the present invention provides for combining the advantages of the traditional isolation approach with the advantages of the traditional integration approach, as described above with respect to the power system of the present invention, without compromising safety against catastrophic failures.

[0063] The power distribution network of the power system may include first type power lanes, each having a respective first type power link. Additionally, the power distribution network of the power system may include one or more second type power lanes, each having a respective second type power link. Each first type power lane may connect at least one associated power source with at least one associated electrical load, allowing at least one associated power source to drive at least one associated electrical load without necessarily driving via another first type power lane. Additionally, each second type power lane may be connected or connectable with at least two associated first type power lanes, allowing transmission of power between the first type power lanes, such that load balancing may be achieved for the electrical loads associated with those first type power lanes across the power sources associated with those first type power lanes.

[0064] For such a power distribution network, the method may preferably include changing an operating mode of one or more second type power links from a first operating mode to a second operating mode to isolate the electrical fault in an electrical fault mitigation mode.

[0065] The method may preferably further include maintaining one or more second type power links in the first operating mode and / or changing the operating mode of one or more second type power links from the second operating mode to the first operating mode for load sharing across the power sources in the normal operating mode or / and for restoration of partial load sharing across the power sources in the electrical fault mitigation mode.

[0066] To be advantageous, the method of the present invention may generally include: i) a first fault isolation step, resulting in isolation of power lanes from each other by switching at least one power link from its first operating mode to its second operating mode; ii) a subsequent second fault isolation step, resulting in fault isolation in power lanes still affected by the electrical fault by switching a power link from its first operating mode to its second operating mode; and iii) a subsequent third fault isolation step, resulting in partial restoration of load balancing for electrical loads not affected by the electrical fault across power sources not affected by the electrical fault by switching at least one power link that is isolated from the electrical fault by at least one other power link that is in the second operating mode from its second operating mode to its first operating mode.

[0067] When first and second types of power lanes and first and second types of power links are provided, the method may preferably include: i) a first fault isolation step, resulting in isolation of the first type of power lanes from each other by switching at least one second type of power link from its first operating mode to its second operating mode; ii) a subsequent second fault isolation step, resulting in fault isolation in a first type of power lane that is still affected by the electrical fault by switching a first type of power link included in this power lane from its first operating mode to its second operating mode; and iii) a subsequent third fault isolation step, resulting in partial restoration of load balancing for electrical loads not affected by the electrical fault across power sources not affected by the electrical fault by switching at least one second type of power link, which is isolated from the electrical fault by at least one other second type of power link and is in the second operating mode, from its second operating mode to its first operating mode.

[0068] By undertaking the first, second and third fault isolation stages in succession, significant advantages are realized as described above with respect to the power system of the present invention configured to provide electrical fault isolation.

[0069] In view of the above, the present invention provides a method for safely isolating electrical faults, particularly short circuits, in a power distribution network, which uses two or more stages of circuit protection devices operating at different speeds. Advantageously, the uniquely fast isolation time and resettable nature of solid-state power controllers (SSPCs) may be utilized to enable safe load sharing while preventing the propagation of electrical faults.

[0070] The invention further provides a generic power system for an aircraft, characterised in that it is adapted to operate according to the method of the invention.

[0071] The inventive power system and the method for operating the power system may in principle be applied to or provided within any kind of aircraft. The invention therefore provides an aircraft comprising a power system as described above or configured to operate according to the inventive method as described above. The aircraft is preferably at least one of a single-seater aircraft, an aircraft with vertical take-off and landing capability, and a canard-type aircraft. Furthermore, the aircraft is preferably an electric aircraft as discussed above.

[0072] According to a preferred embodiment, the power system may comprise at least one group of common type electrical loads in the form of aircraft equipment having critical relevance to maintaining the safe operation of the aircraft, the aircraft equipment being arranged on one or both of the aircraft fuselage and the aircraft wings in a number and configuration to provide resilience to failures such that various subgroups of the plurality of aircraft equipment, each having at least two common types of aircraft equipment, may fail without compromising the flight performance and controllability of the aircraft. The common type of aircraft equipment may be the aircraft's electric lift / thrust units.

[0073] Advantageously, the aircraft equipment of the subgroup, or of each respective subgroup, is associated with one particular common power lane of the power distribution network of the power system and is commonly driveable via this common power lane, and the aircraft equipment of the subgroup, or of each respective subgroup, is arranged and mounted symmetrically distributed on one or both of the aircraft fuselage and the aircraft wings, so that an electrical fault directly or indirectly affecting the common power lane and resulting in a failure of the aircraft equipment of this subgroup does not jeopardize the flight performance and controllability of the aircraft.

[0074] Each particular common power lane of the power distribution network may be a first type power lane as discussed above. Load balancing across multiple or all subgroups may be enabled by a second type power link as discussed above. [Brief description of the drawings]

[0075] [Figure 1] 1 shows a schematic of an aircraft flight control system comprising a user interface for a pilot, redundant flight control computer systems, and an electronic or optoelectronic bus system connecting aircraft equipment to the flight control computer system, the aircraft equipment belonging to the aircraft power system (not shown). [Diagram 2] FIG. 1 is a schematic diagram of a canard-type aircraft of a first variant seen from above, which may be realized as a single-seater aircraft with VTOL capability and may be provided with an aircraft device according to the present invention and a power system including a power source that supplies power to the aircraft device. [Diagram 3] FIG. 11 is a schematic diagram of a canard-type aircraft of a second variant seen from above, which may be realized as a single-seater aircraft with VTOL capability and may be provided with a power system according to the present invention. [Figure 4]Two types of lift / thrust units are shown diagrammatically in sub-figures 4a) and 4b), comprising three propulsion engines mounted on or integrated into the flap, as shown in FIG. 4a), or one propulsion engine mounted on or integrated into the flap, as shown in FIG. 4b). [Diagram 5] The lift / thrust unit of FIG. 4 is shown in side view in sub-figures 5a), 5b), 5c) and 5d) together with the respective aircraft wing and at four different flap deflection angles relative to the wing. [Figure 6] 1 illustrates a schematic of a typical electrical power system for an aircraft. [Figure 7] 1 illustrates a schematic of an aircraft power system with a power distribution network illustrating a first conventional approach; [Figure 8] 1 illustrates a schematic of an aircraft power system with a power distribution network illustrating a second and third conventional approach. [Figure 9] 9 shows a schematic of an aircraft power system illustrating an alternative to the conventional approach of FIG. 8. [Figure 10] 1 illustrates generally a line topology suitable for a power distribution network of an aircraft power system in which the present invention may be implemented; [Figure 11] 11 illustrates diagrammatically a first variant of the network topology according to FIG. [Figure 12] 11 illustrates diagrammatically a second variant of the network topology according to FIG. [Figure 13] 1 illustrates generally a ring topology suitable for a power distribution network of an aircraft power system, on the basis of which the present invention may be implemented. [Figure 14] 1 illustrates generally a star topology suitable for a power distribution network of an aircraft power system, on the basis of which the present invention may be implemented. [Figure 15]1 illustrates generally a star topology suitable for a power distribution network of an aircraft power system, which is particularly preferred and on which the present invention may be implemented. [Figure 16] A simplified version of a canard-type aircraft according to FIG. 2 is shown diagrammatically in sub-figure 16a), a non-preferred configuration of the aircraft's power system is illustrated in sub-figure 16b) and a preferred configuration of the aircraft's power system is illustrated in sub-figure 16c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] [Detailed Description] In the following, a "first approach" and a "second approach" are described for realizing the main advantages of traditional power network integration as well as the main advantages of traditional power network separation in a preferred and synergistic manner, both of which are approaches of the present invention, and therefore all of the examples given for implementing the two approaches are non-limiting exemplary embodiments of the present invention. However, in the context of the present disclosure, the "first approach" is preferred over the "second approach".

[0077] 1-5 illustrate non-limiting examples of aircraft that may be designed with a power system in accordance with the present invention.

[0078] 1 shows and describes a schematic, non-limiting example of an aircraft flight control system 10. The flight control system comprises a flight control computer system 12, which may be realized according to conventional concepts, in particular concepts providing redundancy. An example is such a conventional triplex architecture, comprising three redundant flight control computers 12a, 12b and 12c, which may be redundantly connected, on the one hand, to pilot user interfaces and, on the other hand, to aircraft elements and devices controlled on the basis of the pilot's commands. As examples of conventional redundancy concepts, reference may be made to US 7,337,044 B2, US 8,935,015 B2 and US 8,818,575 B2.

[0079] In FIG. 1, various components of the aircraft are represented generally by elements 14-20, which may represent sensors, actuators (such as actuators for controllably operating moving surfaces such as flaps), propulsion engines, etc., which may be controlled and monitored by flight control computer system 12 via a suitable control bus system, such as a CAN bus system 22.

[0080] Flight control system 10 further includes a pilot user interface that may include a left side stick arrangement 30a and a right side stick arrangement 30b, the left side stick arrangement including a left side stick 32a having a side stick sensor assembly 38a, and the right side stick arrangement including a right side stick 32b having a side stick sensor assembly 38a. Flight control computer system 12 may receive control signals from the pilot user interfaces via electronic or optical coupling links 42a and 42b.

[0081] Figures 2 and 3 show, as non-limiting examples, two canard-type aircraft to which the present invention may be applied and which may be equipped with a flight control system 10 as illustrated in Figure 1. The canard-type aircraft 200 has a fixed left rear or fixed left main wing 202 and a fixed right rear or fixed right main wing 204 at the aft part of the aircraft fuselage 203, and a fixed left front or fixed left canard 206 and a fixed right front or fixed right canard 208 at the forward part of the aircraft fuselage. Each wing is provided with an array of a plurality of flaps 210, 212, 214 and 216, respectively. For example, there may be at least six flaps per front or canard wing and at least twelve flaps per rear or canard wing.

[0082] The embodiment shown in FIG. 2 has two flaps per front or canard and four flaps per rear or main wing, while the embodiment shown in FIG. 3 has six flaps per front or canard and twelve flaps per rear or main wing.

[0083] The flaps of both embodiments are pivotally or movably mounted to the respective wings and can be pivoted about a pivot axis or moved at a pivot part by respective electric actuator devices, preferably independently for each flap. Each flap can be pivoted between an upper first operating position and a lower second operating position. Each flap can be in a position with minimal or negligible inclination relative to the longitudinal axis of the aircraft, possibly the upper first operating position, and in a position with maximal downward inclination relative to the longitudinal axis of the aircraft, possibly the lower second operating position. However, if the position with the maximum downward inclination coincides with the vertical direction of the flap, the lower second operating position can alternatively be beyond the position with the maximum downward inclination, so that the flap point is slightly forward.

[0084] At least one propulsion engine in the form of an electrically powered ducted propeller is attached to each of these flaps. The ducted propeller is preferably attached to the upper surface of the respective flap. Alternatively, the propulsion engine may be integrated with the respective flap in such a way that the air channel of the respective propulsion engine, in which the respective ducted propeller rotates, is located above and aligned with the upper surface of the respective front or rear wing.

[0085] Preferably, the flaps may be in a position corresponding to a lower second operating position, or another operating position between the first and second operating positions, in which the ducted propellers provide only a downward vertical thrust that provides the aircraft with vertical take-off and landing (VTOL) capability. In the upper first operating position, or another operating position between the first and second operating positions, in which the flaps extend in their longitudinal direction, or at a minimum angle to the longitudinal direction of the aircraft, the operating ducted propellers provide maximum forward thrust to the aircraft. The flaps operate not only to control the thrust direction of the propulsion engines or propulsion modules, but also as moving surfaces to affect the aircraft's motion in the air according to conventional aerodynamic principles.

[0086] In the embodiment shown in Fig. 2, the flap is provided with a propulsion module in which a number of propulsion engines in the form of ducted propellers are integrated. For example, such a propulsion module may comprise three such propulsion engines, so that each flap is provided with three propulsion engines, each in the form of a ducted propeller. In this case, the aircraft is provided with a total of 36 propulsion engines.

[0087] FIG. 4a) shows a schematic diagram of such a propulsion module 230 comprising an array of three propulsion engines 232a, 232b and 232c and attached to a flap 234, which may be any one of the flaps 210, 212, 214 and 216 shown in FIG.

[0088] In the embodiment shown in Figure 3, each flap is provided with a propulsion engine in the form of a ducted propeller, so that the aircraft is provided with 36 propulsion engines in total.

[0089] Figure 4b) shows diagrammatically such a flap 234 with a propulsion engine 232 attached thereto. The flap 234 may be one of the flaps 210, 212, 214, and 216 of Figure 3.

[0090] FIG. 4 shows a schematic representation of each flap 234 together with the propulsion modules 230 or propulsion engines 232 as viewed from the rear of the aircraft.

[0091] 5 shows a schematic side view of a respective wing 236 of an aircraft, which may be any one of the wings 202, 204, 206 and 208 of FIGS. 2 and 3, and a respective flap 234, in which a respective propulsion module 230 or a respective propulsion engine 232 is attached to the respective flap 234 for different deflection angles of the flap relative to the wing. For example, a minimum or zero deflection angle as shown in FIG. 5a) provides the aircraft with maximum forward thrust, and a maximum deflection angle or a deflection angle of 90 degrees as shown in FIG. 5d) provides the aircraft with maximum or only vertical thrust downward to achieve vertical take-off and landing (VTOL) capability. The maximum deflection angle may even be greater than 90 degrees, resulting in thrust in a direction having a downward component and a rearward component.

[0092] Intermediate deflection angles of the flaps, as illustrated in Figures 5b) and 5c), provide thrust in a direction having a downward component and a forward component according to the respective deflection angle. The deflection angle may preferably be continuously varied between the minimum and maximum deflection angles. A suitable flap actuator or flap actuator arrangement operating between each wing 236 and each flap 234 is shown diagrammatically in Figure 5 at element 240. A suitable pivot joint or pivot joint arrangement pivotally connecting the flap 234 to the wing 236 is shown diagrammatically in Figure 5 at element 242.

[0093] In Fig. 3, the lift / thrust units, each comprising a flap 234 and a propulsion engine 232 and a flap actuator or flap actuator arrangement 240 as shown in Fig. 4b) and Fig. 5, have associated identification numbers shown in the insert of Fig. 3, which are associated with the wings and canards. The six flaps or lift / thrust units 214 of the canard 206 are assigned identification numbers 1.1 to 1.6. The six flaps or lift / thrust units 214 of the canard 208 are assigned identification numbers 2.1 to 2.6. The twelve flaps or lift / thrust units 210 of the wing 202 are assigned identification numbers 3.1 to 3.12. The twelve flaps or lift / thrust units 212 of the wing 204 are assigned identification numbers 4.1 to 4.12.

[0094] Identification numbers 1.1, 2.1, 3.1 and 4.1 respectively identify the innermost flaps or lift / thrust units adjacent or near the fuselage 203, identification numbers 1.6, 2.6, 3.12 and 4.12 identify the outermost flaps or lift / thrust units furthest from the fuselage 203, other flaps or lift / thrust units and their locations along the respective wings or canards are correspondingly identified by the insertion of the four identification numbers in FIG. 3.

[0095] In both embodiments, the propulsion engines 232 or propulsion modules 230 located on the wings 202, 204, 206 and 208, and the flap actuators 240 associated with the flaps 234 of the four arrays of flaps 210, 212, 214 and 216 are aircraft devices such as elements 14, 16, 18 and 20 in FIG. 1, which are controlled by the flight control computer system 12.

[0096] According to a preferred embodiment, all these aircraft devices are electrically powered aircraft devices, which are driven by power provided by a plurality of storage batteries of the aircraft. The aircraft devices are electric loads of the aircraft's power system, and the storage batteries are power sources of the aircraft's power system. The power system comprises a power distribution network, which is configured to connect the power sources to the electric loads, such that each electric load or aircraft device can be driven by at least one associated power source or storage battery via at least one associated power lane of the power distribution network. The present invention relates to an electric power system and a power distribution network thereof for an aircraft, such as the electric power system and the power distribution network thereof referred to in connection with the exemplary embodiments of Figures 1-5.

[0097] Fig. 6 shows, in a schematic way, such a power system 300 as provided by the present invention. The power system comprises a plurality of power sources or accumulators 302, in the schematic embodiment shown, referred to individually as power sources A, B, C and D, and a plurality of electrical loads, which in the present case are five electrical loads 304, referred to individually as loads AA, BB, CC, DD1 and DD2, and which are typically electrically powered aircraft equipment as mentioned above. The power sources 302 and the electrical loads 304 are connected or connectable via a power distribution network 306, which is only symbolically shown in Fig. 6. Each of the electrical loads may represent a plurality of electrical loads connected in parallel with the power distribution network 306, as illustrated by electrical loads DD1 and DD2, which together form electrical load DD, driven via the power distribution network.

[0098] According to a conventional approach, the power distribution network 306 would be realized as an isolated network with independent power lanes, in this example, four independent power lanes 308a, 308b, 308c, and 308d as shown in FIG. 7, each power lane connecting one specific power source with one specific electrical load. Each of the power lanes is provided with a respective power link a, b, c, and d of a set of power links 310, which are circuit protection devices, also commonly known as "CPDs", that protect the downstream wiring and downstream loads of the respective power lane from damage in the event of a short circuit. For the sake of brevity, the power links 310 are referred to as "CPDs" in the following only as a non-limiting example. Such CPDs can be readily selected by those skilled in the art as appropriate for the wiring or power lane to be protected. CPDs having typical tripping time constants, for example on the order of about 10 ms, may be used as appropriate for the particular power distribution network power lane to be protected and the particular environment.

[0099] Because the power distribution network is separated into separate power lanes 308, such that a fault on one power lane cannot affect another power lane, the separated network has the substantial advantage of being fault tolerant to a certain degree. In the example illustrated in Figure 7, an electrical fault on load BB would cause an interruption of power on power lane 308b until CPDb isolates the electrical fault. The other power lanes are unaffected.

[0100] The drawback of an isolated network is that it does not allow load balancing: if the loads will not have equal power consumption, then there will be uneven demand on the power sources, which will cause the batteries to be discharged unevenly, which can limit the performance of the electric aircraft.

[0101] Any alternative network that utilizes integration rather than separation would be advantageous for load balancing. A corresponding integrated network is illustrated diagrammatically in FIG. 8 by the left network portion formed by power lanes 308a and 308b with power sources A, B, electrical loads AA and BB, and CPDa and b. These two power lanes are connected by a connecting lane 312, thereby realizing load balancing across power sources A and B to the associated electrical loads AA and BB. However, any electrical fault that occurs to one of these power lanes will also affect the other power lane and will propagate through the network, causing a power interruption for all lanes connected to the lane directly affected by the electrical fault until the fault is isolated.

[0102] Thus, in the illustrated example, since the connecting lane 312 is located downstream of CPD a and b, an electrical fault in load BB would cause a power interruption not only in power lane 308 a but also in power lane 308 b, and would not even be able to be isolated. Only if the connecting lane 312 would connect power lanes 308 a and 308 b upstream of CPD a and b, as illustrated in FIG. 9, would a possible electrical fault in load D be isolated by CPD b such that load AA could then be powered from power sources A and B.

[0103] A simultaneous power interruption across the entire power distribution network is typically not acceptable for a safety / critical power distribution network such as that for an aircraft.

[0104] There are three other drawbacks: i) more energy will be released since the electrical fault is fed by both power sources A and B; ii) the CPD will have to interrupt at a higher fault current if placed downstream of the connecting lane 312 since the electrical fault is fed by both power sources A and B; and iii) depending on the capacity of the network power sources and the response time of the CPD, other CPDs may also erroneously isolate, which will lead to a loss of energy supply to load AA as well as load BB, even though load AA is not at fault.

[0105] Figures 8 and 9 illustrate an integrated network as well as a switched network, which is a kind of hybrid solution still adopted in conventional aerospace technology. Such networks use switches to provide integration as well as separation, depending on the situation. According to Figures 8 and 9, power lanes 308c and 308b are connected via a connection lane 314 equipped with a power link 316 in the form of a switch SW, which according to Figure 8 is located downstream of CPDs c and d and according to Figure 9 is located upstream of CPDs c and d.

[0106] Since a fault occurring while switch SW is closed can propagate between the power lanes, the action of closing switch SW results in a significant reduction in the safety margin. Therefore, according to conventional aerospace technology, switch SW is closed following a fault only when the system is operating in a degraded mode, and therefore in normal operation, the benefits of integration are not realized. An example of the introduction of integration corresponding to such a fault is the failure of power source D, whereby load DD or loads DD1 and DD2 would no longer receive power from source D via power lane 308d in an isolation state of the power distribution network 306. By closing power link 316 or switch SW, these loads can receive power from power source C, which would then have to drive load CC together with load DD.

[0107] The main advantages of network separation, together with network integration, can be realized in a favorable synergistic manner according to two alternative approaches proposed herein, referred to as the "first approach" and the "second approach", as described below based on the exemplary non-limiting network topology as shown in the examples in Figs. 10-15. In the following description, the following terminology is used: the power lanes 308 connecting the respective power sources to the respective electric loads via respective power links such as CPDs, i.e., the power lanes 308a, 308b, 308c and 308d in Fig. 10, are referred to as "first type of power lanes". These first type of power lanes comprise one of each of the above-mentioned power links 310, i.e., one of the power links a, b, c and d in the illustrated example, which are typically realized as CPDs as described. These power links 310 are referred to as "first type of power links". For the sake of brevity, these power links are also referred to as "CPDs" below, only in the sense of a non-limiting example.

[0108] According to the embodiment of Fig. 10, these first type power lanes are connected to each other in pairs by connection lanes 314, i.e. individual power lanes 314a, 314b and 314c, which respectively comprise respective power links ab, bc and cd of the set of power links 316. These connection lanes 314 or 314a, 314b and 314c are referred to as "second type power lanes" and their power links ab, bc and cd are referred to as "second type power links". According to Fig. 10, these second type power links 316, individually referred to as ab, bc and cd, are provided upstream of the power links. Depending on the application and approach implemented, these second type power links may be CPDs, switches, SSPCs (Solid State Power Controllers), etc. Preferred embodiments according to the two proposed approaches use either an SSPC or a switch as the second type of power link, and therefore for brevity hereinafter, these second type of power links will be referred to as one or more "SSPC / SW" (where SW stands for switch) for non-limiting example purposes only.

[0109] FIG. 11 shows an alternative configuration, where second type power lanes or SSPC / SW 316 (ab, bc, cd) are placed downstream of first type power links or CPD a, b, c and d.

[0110] As shown in Fig. 12, one may also choose to provide one or more SSPC / SW upstream of the CPD of the associated first type power lane, and one or more second type power links downstream of the first type power links of the associated first type power lane. The second type power lanes 314a, 314b are arranged upstream of CPDa, b, and c with their SSPC / SWab and bc, and the second type power lane 314c is arranged downstream of CPDc and d with its SSPC / SWcd. The network topologies of Figs. 10, 11, and 12 allow load sharing or partial load sharing across power sources A, B, C, and D for electrical loads AA, BB, CC, and DD in a line topology, since the loads are connected or can be connected via SSPC / SWab, bc, cd included in a kind of load sharing connection line formed by the second type power lanes 314a, 314b, and 314c.

[0111] Even more advantageous is the connection of the second type connection lanes with their SSPC / SW in a ring configuration, which allows load sharing or partial load sharing across power sources A, B, C and D for loads AA, BB, CC and DD in a ring topology as shown in Fig. 13. The connection between the first type power lanes 308c and 308d is shown by a dotted line in Fig. 13 to indicate that more first type power lanes with CPDs may be provided or included in the load sharing or partial load sharing via the load sharing connection ring line formed by the second type power lanes. The possibility that no more first type power lanes are provided and therefore no second type power lane 314c with SSPC / SWcd is provided is also shown in Fig. 13.

[0112] The ring lane is closed by a second type power lane 314d with an SSPC / SWad, which connects the first type power lanes 308a and 308d.

[0113] Another possibility is to connect the first type power lanes with their SSPC / SW in parallel to form a kind of star topology for load sharing or partial load sharing. Figure 14 shows a non-limiting example, where the first type power lane 308a is connected or connectable to each of the other illustrated first type power lanes via respective second type power lanes, i.e., first type power lane 308b via second type power lane 314a, first type power lane 308c via second type power lane 314e, and first type power lane via second type power lane 314f. These second type power lanes each have their respective SSPC / SWs designated ab, ac, and ad.

[0114] A disadvantage of the shown configuration is that a fault directly affecting the first type power lane 308a will also affect all other first type power lanes, and after isolation of the fault, load sharing or partial load sharing will no longer be possible.

[0115] Therefore, a load balancing configuration such as a star as shown in FIG. 15 is preferred, which uses not the first type power lane as the center of the hub or star configuration, but another connection lane 320, which is connected or connectable to each of the first type power lanes 308a, 308b, 308c and 308d via respective second type power lanes 314g, 314h, 314i and 314j, each having a respective SSPC / SWax, bx, cx and dx.

[0116] All these power distribution network configurations or topologies are non-limiting examples only, and all these topologies may be realized in combination with the respective network parts of the power distribution network, and other topologies known to those skilled in the art may also be implemented, such as the topology known in US2020 / 0010187A1 as well as meshed topologies.

[0117] Now, the configuration of the power distribution network and the operation of the power distribution network according to the above preferred proposed approach will be described. [First approach] According to the first approach described above, an integrated power distribution network 306 for normal operation is provided, which in the event of an electrical fault can switch in a very fast manner to an isolated or partially isolated power distribution network. For this purpose, the second type of power link 316 is realized as a very fast acting solid-state switch, or a very fast acting solid-state CPD, or a similar or preferred solid-state power controller (SSPC), or a load channel of one or more solid-state power controllers (SSPCs) of the power distribution network.

[0118] These second type power links, preferably SSPCs, can be conductive in normal operation and will thereby be transparent with respect to load sharing. However, these second type power links are configured to isolate very quickly, for example within 10-20 μs, in order to introduce isolation if an electrical fault is detected. In the following, these second type power links will be referred to as "SSPCs" only as a non-limiting example. In general, it is preferred that isolation times of about 100 μs, more preferably less than 100 μs, and most preferably about 10-20 μs are realized by the SSPCs. However, longer isolation times, for example of the order of 1 ms, will not be excluded.

[0119] SSPCs are well-known electronic devices consisting of one or more conduction or load channels, a current measurement means for each load channel, and logic means implemented in software or hardware such that a load channel may be turned off when a certain current threshold is exceeded, or possibly in response to one or more other trip conditions. Such current thresholds and trip conditions may be readily selected or determined by one skilled in the art based on the design of the power distribution network and the characteristics of the power sources and electrical loads, and therefore the maximum current values ​​and other electrical conditions expected for normal operation without faults. One skilled in the art will consider appropriate safety margins.

[0120] Thereby, a power distribution network is realized which on the one hand takes advantage of the consolidation and benefits from the advantages of load balancing, and on the other hand is also fault-tolerant and secure.

[0121] Consider for example the first type power lanes 308a and 308b with power sources A and B, electrical loads AA and BB, CPDa and b, and the second type power lane 314a with SSPCab in Figures 10 and 11, where the SSPCab is inserted in parallel between the power lanes 308a and 308b. In the normal operation state of the network, this SSPC is in its conducting state, so that the load AA can be equally supplied by the sources A and B, and the load BB can also be equally supplied by the sources A and B. The same applies to the other first type power lanes according to Figures 10 and 11 and the other second type power lanes with their SSPCs, as well as all the corresponding power lanes according to Figures 12-15, which allows load balancing in the normal operation of the power distribution network, but isolates possible electrical faults in a very fast way by introducing a suitable isolation.

[0122] Preferably, fault isolation is realized according to multiple subsequent fault isolation stages, preferably three isolation stages, since an occurring electrical fault may have the consequence that more SSPCs may switch from their conducting state to their non-conducting state than is necessary for fault isolation.

[0123] The first fault isolation stage and the second fault isolation stage can be again described and illustrated based on, for example, power sources A and B, electrical loads AA, BB, their associated first type power lanes 308a and 308b with respective CPDa and b, and their associated second type power lane 314a with SSPCab, according to Figures 10 and 11.

[0124] The first fault isolation stage results in the isolation of this portion of the network to a first type of power lane. If an electrical fault occurs in load BB, then the SSPCab will see an increase in current through power source A supplying the electrical fault and will be isolated very quickly by switching to its non-conducting state. The fault is now isolated to power lane 308b, and power lane 308a may continue normal operation. Little or no power is interrupted in load AA.

[0125] Now, the electrical fault only affects the power lane 308b, so that fault isolation in this lane can be achieved by the second fault isolation stage. Because the electrical fault only affects the first type of power lane 308b, the fault isolation is less urgent. Because the electrical fault only receives electrical energy from power source B, less energy is released in the fault, and CPDb can safely interrupt the fault current. CPDb can safely isolate the fault in the form of a possible short circuit.

[0126] An important advantage of the proposed approach is that the traditional concept of “selectivity” for sequentially coordinating multiple CPDs between power sources and loads so that the CPDs are isolated in the correct order is not relevant or utilized.

[0127] The SSPC or SSPCs may be of any speed and no coordination with other SSPCs and CPDs is required, except that the second type of power link, preferably an SSPC, should be fast enough to allow each SSPC to trip before the CPD of the first type of power link or first type of power lane can trip. Providing a very fast second type of power link is also advantageous to limit the duration of each power interruption. The second type of power link or SSPC does not isolate its own power from the load, but only isolates the first type of power lanes from each other, so that coordination of the second type of power link or SSPC is not as critical as coordination of a particular CPD on the network with prior art approaches.

[0128] The third fault isolation stage provides for restoration of network integrity except for maintaining the degree of isolation required to isolate the electrical fault.

[0129] This fault isolation step is suitable for larger networks with more power lanes, as considered in the context of power sources A and B, and loads AA and BB, shown in FIGS.

[0130] In such an expanded power distribution network 306, it is highly likely that a large number of second-type power links will switch to their non-conducting state during the first isolation stage. This is especially true for SSPCs due to their high sensitivity. Thus, load balancing may be lost even among healthy first-type power lanes.

[0131] For example, in the network 306 of Figures 10 and 11, it may happen that the first type power lane 308b is affected by an electrical fault, but not the first type power lane 308c, and the SSPCcd between the power lanes 308c and 308d switches to a non-conducting state. To isolate this electrical fault, only the SSPCab and bc must switch to a non-conducting state, so the SSPCcd may switch or be switched to a conducting state again as soon as the first type power lane 308c is isolated from the failed first type power lane 308b by the SSPCbc switching to a non-conducting state.

[0132] In the case of the network topology of Figure 10, assuming that an electrical short circuit occurs in electrical load BB, even the other SSPCab and bc may return to their conductive state after fault isolation in the first type of power lane 308b following the second fault isolation stage, i.e., switching of the CPDb of this power lane to its non-conductive state, which interrupts the fault current.

[0133] Having a second type of power lane with a second type of power link or SSPC upstream of the first type of power link or CPD may be preferable in consideration of the possibility that a fault may occur to the electrical loads, in which case all power sources may continue to supply power and contribute to load sharing after restoration of integrity by the third fault isolation stage.

[0134] Providing a second type of power lane with a second type of power link or SSPC downstream of the first type of power link or CPD may be preferable considering the possibility that a power source may fail, in which case all electrical loads may continue to be powered based on load balancing across the remaining power sources after restoration of integrity by the third fault isolation stage.

[0135] Both of these possibilities have their advantages, so a mixed configuration as illustrated in FIG. 12 may be used.

[0136] However, it is not excluded that the second type of power lanes with respective power links of the second type are provided not only downstream but also upstream of the first type of power links. Furthermore, the proposed first approach can be combined with a conventional hybrid approach, i.e. fast-operating second type of power links, in particular SSPCs, are provided on one of the upstream and downstream sides, and conventional switches SW or power links 314 shown in Figures 8 and 9, which are in their blocking state in normal operation and are selectively switched to their conducting state during the third fault isolation stage, are provided on the other of the upstream and downstream sides.

[0137] The third fault isolation stage may be performed independently by individual SSPCs under control of their respective logic means based on the measured electrical conditions of their load channels. Alternatively, a centralized controller of the power distribution network may control the SSPCs to perform the third fault isolation stage, for example, based on status data from the CPDs and SSPCs, and possibly measured electrical conditions of the network.

[0138] The above description of the three fault isolation stages is similarly applicable to other network topologies in Figures 10-15. After the achievement of the second fault isolation stage, all SSPCs among all first type power lanes except the failed first type power lane may be reset to a conductive state to reintroduce load balancing and turn the network into a near-normal operating state. Due to the achieved fault isolation, this operating state of the network may be referred to as the electrical fault mitigation operating mode of the network. Depending on the location of the SSPCs downstream or upstream of the CPDs, it may even happen that all SSPCs may be reset to a conductive state, since one CPD or multiple CPDs implementing fault isolation in each involved first type power lane may be sufficient for fault isolation.

[0139] For aircraft as referenced in connection with Figures 1-5 employing multiple power sources and distributed electric thrust units (EPUs) or lift / thrust units as electrical loads, typically for so-called eVTOL applications, it is advantageous to arrange the EPUs in power lanes in a symmetrical distribution with respect to the geometry of the aircraft such that loss of a power lane has minimal impact on the controllability of the vehicle. This may be achieved by ensuring that a single power lane supplies a well-distributed EPU rather than an adjacent EPU, as in the case of a network configuration such as the single first type power lane described above.

[0140] Figure 16 shows in Figure 16a a simplified schematic version of the aircraft according to Figures 2 and 3 with only six EPUs, namely EPU1 and EPU2 on the front or canard, and EPU3, EPU4, EPU5 and EPU6 on the rear, each of which may represent a unit with multiple propulsion engines.

[0141] 16b shows a schematic allocation that is undesirable because a failure on one power lane affects adjacent EPUs, affecting EPUs that are asymmetric with respect to the axis of symmetry that is the roll axis of the vehicle. Either EPUs 1, 3, 4 or EPUs 2, 5, 6 are affected, with EPUs 1, 3, and 4 located on the front and rear wings of the vehicle's right side, EPUs 3 and 4 located adjacent to each other on the right rear wing, and EPUs 2, 5, 6 located on the front and rear wings of the vehicle's left side, and EPUs 5 and 6 located adjacent to each other on the left rear wing.

[0142] 16c shows the allocation diagrammatically, which is desirable because a failure on one first type power lane does not affect adjacent EPUs, resulting in better symmetry of failed EPUs (with respect to the axis of symmetry, which is the vehicle's roll axis). If one of the power lanes 308a and 308b were to fail, only one of the two EPUs 1 and 2 on the left and right front wings would be affected, and only one individual EPU on the left and right rear wings would be affected, i.e., either EPUs 4 and 5, or EPUs 3 and 6.

[0143] The concepts described with reference to Figures 16 and 16c may be similarly applied to the EPUs or lift / thrust units or propulsion engines and flight actuators of the illustrated embodiments of Figures 2 and 3.

[0144] Generally speaking, a person skilled in the art can provide a sufficient number of common types of aircraft equipment, in particular lift / thrust units, and can arrange these aircraft equipment in an appropriate configuration on the aircraft, in particular on its wings, and can allocate these aircraft equipment in an appropriate manner to power lanes, in particular first type power lanes of the power distribution network, so as to achieve the desired resilience against single or even multiple electrical faults.

[0145] 3, for example, an electrical failure could result in the simultaneous failure of lift / thrust units 3.1 and 3.6 on the left wing 202 and / or lift / thrust units 4.1 and 4.6 on the right wing 204. Therewith, one or two lift / thrust units adjacent to the fuselage and one or two lift / thrust units still fairly close to the fuselage would be affected, which would have no or only a small effect on lateral balance.

[0146] 3, an electrical failure could result in the simultaneous failure of outermost lift / thrust unit 1.6 of left canard 206 and outermost lift / thrust unit 4.12 of right wing 204, and / or outermost lift / thrust unit 2.6 of right canard 208 and outermost lift / thrust unit 3.12 of left wing 202. Again, lateral balance would not be affected, or would be only marginally affected.

[0147] The described principles of achieving resilience against failures based on the proposed approach can naturally be applied to other types of aircraft than those shown in Figures 2, 3 and 16a), as well as to completely different types of aircraft with such a large number of lift / thrust units, propulsion engines, flaps, etc., where not all of these aircraft engines are required to maintain the flight capability and controllability of the aircraft. In order to achieve resilience against single, double or multiple electrical failures, a person skilled in the art, when implementing the present invention, can assign the various aircraft engines to individual power lanes of the power distribution network in such a way that the impact of such single, double or multiple bus failures is minimized. [Second approach] According to the second approach described above, a partially integrated and partially isolated power distribution network 306 is provided for normal operation of the power distribution network and preferably also for a fault mitigation mode of operation. According to this approach, the network is continuously switched between a plurality of different partial load sharing configurations associated with each of a plurality of partial load sharing modes. The power distribution network is continuously assuming these partial load sharing modes, and therefore their partial load sharing configurations, in a time-varying manner. Each of these different partial load sharing configurations corresponds to a different type of partial integration and partial isolation of the network. An even discharge of the power sources can be achieved by this continuous, preferably periodic, switching between the partial load sharing configurations.

[0148] The switching between the different partial load sharing configurations is performed by second type power links 316, which switch synchronously between their conducting and non-conducting states, preferably relatively slow compared to the tripping times of typical circuit protection devices or CPDs, and also compared to typical tripping times of solid-state power controllers (SSPCs). For example, a suitable time scale for switching of the second type power links 316 may be switching between the conducting and non-conducting states in a time interval of one minute. Hence, rather slow electromechanical or solid-state switches are suitable for realizing the second type power links 316, although other components allowing switching between the conducting and non-conducting states may also be used.

[0149] Hereinafter, these second type power links will be referred to simply as one or more "SWs" to represent a suitable switch or suitable multiple switches, by way of non-limiting example only.

[0150] Moreover, as with the first proposed approach described above, the first type of power links may be suitable circuit protection devices or “CPDs.” In the following, these first type of power links will again be referred to simply as one or more “CPDs” by way of non-limiting example only.

[0151] According to a number of different partial load sharing modes successively adopted by the power distribution network, an example of partial load sharing effected across power sources with respect to associated electric loads in a time-varying manner can be given based on the ring topology of Fig. 13. Here, it is assumed that the first type power lane 308c and the first type power lane 308d are directly connected by a second type power lane 314c with a switch SW as a second type power link cd. Correspondingly, the other second type power links ad, ab, and bc are also switches, while the power links a, b, c, and d are CPDs.

[0152] A suitable partial load balancing mode, referred to as stages 1 and 2, is, for example, as follows:

[0153] [Table 1]

[0154] By alternating between phases 1 and 2 periodically during operation, it is ensured that an electrical fault never affects more than half the lanes. According to the two phases 1 and 2, each phase has associated associated power sources A, B, C, and D, and thus corresponding electrical loads AA, BB, CC, and DD, with a number of split load sharing groups, namely split partial load sharing group (A+B, AA+BB) and split partial load sharing group (C+D, CC+DD) in phase 1, and split partial load sharing group (B+C, BB+CC) and split partial load sharing group (A+D, AA+DD) in phase 2. These groups in each phase are referred to as "split groups" since the groups have no common elements.

[0155] Every power source has the opportunity for integration with other power sources for load sharing, either directly or through another power source if provided.

[0156] This solution is scalable to any number of power lanes.

[0157] Other allocations of power sources and loads to the various stages are possible, for example as shown below.

[0158] [Table 2]

[0159] According to this embodiment, each stage assigns power sources and loads to a respective partial common load sharing group, i.e., common load sharing group (A+B, AA+BB) in stage 1, common load sharing group (B+C, BB+CC) in stage 2, common load sharing group (C+D, CC+DD) in stage 3, and common load sharing group (A+D, AA+DD) in stage 4.

[0160] However, no particular advantages over the first embodiment would be realized.

[0161] If network criticality tolerates the loss of more than half the lanes at any one time, then additional stages are possible, where three first type power lanes participate in load balancing simultaneously, for example as follows:

[0162] [Table 3]

[0163] According to this embodiment, each stage reallocated power sources and loads to respective partial common load sharing groups, i.e., common load sharing group (A+B+C, AA+BB+CC) in stage 1, common load sharing group (B+C+D, BB+CC+DD) in stage 2, common load sharing group (A+C+D, AA+CC+DD) in stage 3, and common load sharing group (A+B+D, AA+BB+DD) in stage 4.

[0164] In the event of an electrical fault, each first type power lane would be excluded from further partial load sharing to isolate the electrical fault. Partial load sharing may nevertheless continue with multiple different partial load sharing modes successively employed by the network.

[0165] Should a power source C or a load CC have an electrical fault, for example the following steps may be periodically adopted by the network.

[0166] [Table 4]

[0167] These stages 1' and 2', which correspond to stages 1 and 4 in the second embodiment described above, correspond to a partial fault isolation load sharing mode of the power distribution network. These stages are part of stages 1 to 4 in the second embodiment described above, with stage 1' corresponding to stage 1 therein and stage 1' corresponding to stage 4 therein.

[0168] Alternatively, in the electrical fault mitigation operation mode of the power distribution network, if the electrical fault must be isolated, persistent load balancing across the healthy first type power lane power sources may be implemented for those loads. In this embodiment, again, the following fault mitigation steps may be adopted by the network if power source C or load CC has an electrical fault to persistently adopt fault isolation until the electrical fault is resolved:

[0169] [Table 5]

[0170] Another example is given based on a star topology according to Fig. 15. The power links ax, bx, cx and dx between the connection lane 320 acting as the central node and each first type power lane are again assumed to be switches. Examples of suitable partial load sharing modes or stages are the following stages 1 to 6.

[0171] [Table 6]

[0172] As with other embodiments, this solution is scalable to any number of power lanes and the stages can be transitioned in any order. If network criticality allows for the loss of more than half the lanes, then additional stages are possible, where, for example, three lanes instead of only two, participate in each simultaneous partial load balancing.

[0173] In the event that power lane 308c fails due to a failure of power source C or load CC, the following steps may be periodically undertaken in the electrical fault mitigation mode of operation of the network.

[0174] [Table 7]

[0175] These steps 1', 2' and 3' are part of steps 1 to 6 of the embodiment given for normal operation, with step 1' corresponding to step 1, step 2' corresponding to step 3 and step 3' corresponding to step 5.

[0176] Alternatively, if desired, in an electrical fault mitigation mode of operation of the power distribution network, persistent load balancing across the power sources of healthy type 1 power lanes may again be implemented for those loads.

[0177] The transition between the various stages or partial load sharing modes of each implementation is preferably performed by first opening the currently closed switches and then closing the switching that will be closed to realize the next stage. This ensures that the stage transition does not involve any reduction in the safety margin. Therefore, switching between stages is preferably not performed directly, but only after an intermediate stage without partial load sharing across the power sources.

[0178] As discussed and explained with reference to Figures 16 and 3, the critical loads may be appropriately distributed and symmetrically located on the first type power lanes and on the aircraft wings and fuselage to provide resilience and maintain vehicle controllability, which also applies in the context of the proposed second approach.

[0179] Advantageously, it may be provided that the various partial common or decoupled partial load sharing groups of the partial load sharing mode or partial load sharing phase are formed in such a manner that the critical loads or aircraft devices of each respective common or decoupled load sharing group are well distributed symmetrically over the wings and / or fuselage of the aircraft, so that a failure of one of these groups is not fatal and does not affect the controllability of the aircraft. In such a case, it is not very important for the power distribution network to notice and react very quickly to the occurrence of an electrical fault in order to isolate the electrical fault and assume an electrical fault mitigation operation mode.

[0180] There are many possibilities how a person skilled in the art may implement in detail the proposed concepts and approaches of the present disclosure. A person skilled in the art may also decide to implement both proposed approaches in the power distribution network of an aircraft, for example by applying one of these approaches for one network section and the other approach for another network section. Furthermore, the power distribution network may in principle be configured or may be configurable according to both approaches if the power links of the second type are appropriately selected.

[0181] Terms such as "power source", "electrical load", "power lane", "first type of power lane", "second type of power lane", "power link", "first type of power link" and "second type of power link" used above are essentially general terms describing any function in any technical context, without necessarily implying a specific structure and specific elements used to realize these functions. To that end, multiple power links can be incorporated into one respective power network device. One or more first type power links and even one or more second type power links can be incorporated into one respective power network device. Such power links incorporated into a power network device can share a connection port of the power network device, for example, such that one connection port of the power network device is simultaneously a connection port of a first type of power link and a connection port of a second type of power link. Such a power network device may also include a power lane or a power lane section as incorporated into the device together with the respective power links in this sense.

[0182] The power distribution network (306) of the aircraft power system (300) is operated in at least one normal operating mode such that it provides load balancing for electrical loads (AA, BB, CC, DD) across the power sources (A, B, C, D), and the power distribution network (306) is operated in at least one electrical fault mitigation operating mode that provides electrical fault isolation such that, in the event of an electrical fault, a network portion of the power distribution network (306) having an electrical fault is isolated from at least one other network portion of the power distribution network. [Explanation of symbols]

[0183] 10... flight control system, 12... flight control computer system, 12a, 12b, 12c... flight control computer, 14, 16, 18, 20... aircraft device, 22... control bus system, 30a, 30b... left and right side stick device, 32a, 32b... left and right side stick, 38a, 38b... sensor assembly, 42a, 42b... connecting link, 200... canard type aircraft, 202... left rear wing, 203 ...fuselage, 204...right rear wing, 206...left front wing, 208...right front wing, 210, 212, 214, 216; 234...flaps, 230...propulsion module, 232, 232a, 232b, 232c...propulsion engines, 3.1-3.12...left rear wing lift / thrust unit, 4.1-4.12...right rear wing lift / thrust unit, 1.1-1.6...left front wing lift / thrust unit, 2.1-2.6...right front wing lift / thrust unit, 2 36...wing, 240...flap actuator, 242...pivot joint, 300...power system, 302; A, B, C, D...power source, 304; AA, BB, CC, DD1, DD2, DD...electrical load, 306...power distribution network, 308; 308a, 308b, 308c, 308d...power lanes, first type power lanes, 310; a, b, c, d...first type power links, 312, 314...power lanes, 316; S W... power link; switch, 314; 314a, 314b, 314c, 314d, 314e, 314f, 314g, 314h, 314i, 314j... second type of power lane, 316; ab, bc, cd, ad, ac, ad, ax, bx, cx, dx, 312, 314, 314a... second type of power link, 320... connection lane, EPU1, EPU2, EPU3, EPU4, EPU5, EPU6... electric propulsion unit

Claims

1. A power system for an aircraft, comprising a plurality of electrical loads, a plurality of power sources, and a power distribution network configured to connect the power sources to the electrical loads, wherein each electrical load can be driven by at least one associated power source via at least one associated power lane of the power distribution network, the power distribution network comprises at least one of a circuit protection device and a circuit switching device having a plurality of switchable or interruptible power links, each power link has two connection ports, and each power link is configured to connect the connection ports to transmit power from a driving power lane or a driving power lane section connected to one of the connection ports to a driven power lane or a driven power lane section connected to the other one of the connection ports in a first operating mode, and to interrupt the connection between the connection ports to prevent power transmission between the driving power lane or the driving power lane section and the driven power lane or the driven power lane section in a second operating mode, the power distribution network is configured to operate in at least one normal operating mode and at least one electrical fault mitigation operating mode, in the normal operating mode, the power distribution network provides load sharing across power sources (A, B, C, D) such that at least one power source group (A, B, C, D) of the plurality of power sources commonly drives at least one associated electrical load group (AA, BB, CC, DD) of the plurality of electrical loads via an associated power lane or power lane section and at least one power link that is in the first operating mode, in the electrical fault mitigation mode, the power distribution network provides electrical fault isolation such that a network section of the power distribution network having an electrical fault is isolated from at least one other network section of the power distribution network by at least one power link that is in the second operating mode, A power system.

2. The power system according to claim 1, wherein the power distribution network causes load distribution across all power sources (A, B, C, D) such that all power sources of the plurality of power sources commonly drive all electrical loads (AA, BB, CC, DD) of the plurality of electrical loads via respective power lanes or power lane sections and respective power links in the first operating mode, even in the normal operating mode. The power distribution network is configured to assume the electrical fault mitigation operating mode in such a manner that electrical faults occurring in a power source or an electrical load can be isolated so that a plurality or all power sources not affected by an electrical fault can drive a plurality or all electrical loads not affected by the electrical fault. A power system.

3. The power system according to claim 1, wherein the power distribution network comprises a plurality of first type power lanes. Each of the first type power lanes is associated with at least one associated power source (A; B; C; D) that is not associated with another of the first type power lanes, and each of the first type power lanes is associated with at least one electrical load (AA; BB; CC; DD) that is not associated with another of the first type power lanes, such that at least one associated power source is connected to or connectable to at least one associated electrical load via respective ones of the first type power lanes, and at least one of the power sources can drive at least one of the electrical loads via respective ones of the first type power lanes without necessarily involving driving via another of the first type power lanes. A power system.

4. The power system according to claim 3, wherein a plurality of the first type of power lanes are connected or connectable via a connection lane device of the power distribution network, the connection lane device includes one or more second type of power lanes, and by transmitting power between these first type of power lanes via at least one of the second type of power lanes, a power system enabling load distribution with respect to electrical loads (AA, BB, CC, DD) associated with at least one group of these first type of power lanes or all of these first type of power lanes across power sources (A, B, C, D) associated with these first type of power lanes.

5. The power system according to claim 3, wherein each of the first type of power lanes includes a first type of power link, and in the first operating mode, enables transmission of power from at least one of the associated power sources (A; B; C; D) to at least one of the associated electrical loads (AA; BB; CC; DD) via the first type of power link, and in the second operating mode, blocks transmission of power from at least one of the associated power sources to at least one of the associated electrical loads via the first type of power link, and each of the first type of power links is preferably configured to change its operating mode from the first operating mode to the second operating mode within a trip time interval of the order of a first magnitude in response to at least one preset or presettable electrical trip condition indicating an electrical fault.

6. The power system according to claim 4, wherein each of the second type of power lanes includes a second type of power link, and in the first operating mode, enables transmission of power between the first type of power lanes via the second type of power link, and in the second operating mode, blocks transmission of power between the first type of power lanes via the second type of power link, and each of the second type of power links is preferably configured to change its operating mode from the first operating mode to the second operating mode within a trip time interval of the order of a second magnitude in response to at least one preset or presettable electrical trip condition indicating an electrical fault.

7. The power system according to claim 5, wherein a trip time interval of the order of the first magnitude of the first type of power link significantly exceeds a trip time interval of the order of the second magnitude of the second type of power link.

8. The power system according to claim 6, wherein each of the second type of power links is provided by a respective solid state power controller of the power distribution network, which includes a microcontroller, at least one load channel forming the second type of power link, and at least one solid state switch included in the load channel and operable under the control of the microcontroller. The microcontroller is configured to switch the solid state switch between a conducting state corresponding to the first operating mode of the second type of power link and a non-conducting state corresponding to the second operating mode of the second type of power link, and is configured to monitor at least one current electrical state of the load channel in order to respond to the occurrence of the electrical trip condition by switching the solid state switch from the conducting state to the non-conducting state.

9. The power system according to claim 1, wherein the power distribution network is configured to effect electrical fault isolation by undergoing at least three fault isolation stages subsequent to switching from the normal operating mode to the electrical fault mitigation mode in response to the occurrence of an electrical fault. The first fault isolation stage effects separation of power lanes from each other by at least one power link that switches from its first operating mode to its second operating mode. A subsequent second fault isolation stage effects fault isolation within a power lane still affected by the electrical fault by a power link that switches from its first operating mode to its second operating mode. A subsequent third fault isolation stage effects a partial recovery of load distribution regarding electrical loads not affected by the electrical fault across power sources not affected by the electrical fault by at least one power link that switches from its second operating mode to its first operating mode and is isolated from the electrical fault by at least one other power link in the second operating mode. Power system.

10. A method of operating an aircraft power system comprising a plurality of electrical loads, a plurality of power sources, and a power distribution network configured to connect the power sources to the electrical loads, wherein each electrical load can be driven by at least one associated power source via at least one associated power lane of the power distribution network, the power distribution network comprising a plurality of switchable or interruptible power links, each provided within a respective power lane of the power distribution network for enabling power transmission via the respective power lane in a first operating mode of the power link and for blocking power transmission via the respective power lane in a second operating mode of the power link, The method includes operating the power distribution network in at least one normal operating mode, which results in load sharing across the power sources (A, B, C, D) such that at least one power source group (A, B, C, D) of the plurality of power sources drives in common at least one associated electrical load group (AA, BB, CC, DD) of the plurality of electrical loads via respective power lanes each comprising a power link in the first operating mode, The method further includes operating the power distribution network in at least one electrical fault mitigation operating mode, which results in electrical fault isolation such that a network portion of the power distribution network having an electrical fault is isolated from at least one other network portion of the power distribution network by at least one power link in the second operating mode, Method. **Claim 11** The method according to claim 10, wherein the power distribution network comprises first type power lanes each comprising a first type power link, and the power distribution network comprises one or more second type power lanes each comprising a second type power link, Each said first type power lane enables at least one associated power source to drive at least one associated electrical load without necessarily involving driving via another said first type power lane by connecting at least one associated power source to at least one associated electrical load, Each of the second type of power lanes is connected to, or connectable to, at least two associated first type of power lanes, enabling power transmission between the first type of power lanes and achieving load distribution across the electrical loads (AA, BB, CC, DD) associated with these first type of power lanes over the power sources (A, B, C, D) associated with these first type of power lanes. The method includes changing the operating mode of one or more of the second type of power links from the first operating mode to the second operating mode to isolate an electrical fault in the electrical fault mitigation mode. The method includes maintaining one or more of the second type of power links in the first operating mode for load distribution across the power sources (A, B, C, D) in the normal operating mode and / or for restoring partial load distribution across the power sources in the electrical fault mitigation mode, and / or includes changing the operating mode of one or more of the second type of power links from the second operating mode to the first operating mode. Method.

12. The method according to claim 10, - A first fault isolation step that results in the separation of power lanes from each other by switching at least one power link from its first operating mode to its second operating mode. - A subsequent second fault isolation step that results in fault isolation within a power lane still affected by an electrical fault by switching a power link from its first operating mode to its second operating mode. - A subsequent third fault isolation step that results in a partial restoration of load distribution across the electrical loads not affected by the electrical fault over the power sources not affected by the electrical fault by switching at least one power link isolated from the electrical fault by at least one other power link in the second operating mode from its second operating mode to its first operating mode. A method comprising the above.

13. An aircraft comprising the power system according to claim 1, wherein the aircraft is at least one of a single - passenger aircraft, an aircraft with vertical take - off and landing capabilities, and a tailless aircraft.

14. An aircraft according to claim 13, wherein the power system comprises at least one group of common types of electrical loads in the form of aircraft devices having a significant relevance to maintaining the safe operation of the aircraft, and the aircraft devices are arranged in a number and configuration for achieving resilience against failures such that various subgroups of a plurality of the aircraft devices, each having at least two common types of the aircraft devices, on one or both of the fuselage of the aircraft and the wings of the aircraft, can fail without endangering the flight performance and controllability of the aircraft.

15. An aircraft according to claim 14, wherein the aircraft devices of the subgroup or each respective subgroup are associated with one specific common power lane of the power distribution network of the power system and can be commonly driven via this common power lane, and the aircraft devices of the subgroup or each respective subgroup are symmetrically distributed and arranged on one or both of the fuselage of the aircraft and the wings of the aircraft, so as not to directly or indirectly affect the common power lane and not to endanger the flight performance and controllability of the aircraft due to an electrical fault that causes a failure of the aircraft devices of this subgroup.

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