Power distribution systems in an electric aircraft

Abstract

An electric aircraft comprising: a fuselage; one or more wings mounted on the fuselage; a plurality of propellers pivotable between lift and forward propulsion configurations; and a plurality of battery packs, wherein at least two of the plurality of battery packs are configured to power: at least a portion of a first propeller of the plurality of propellers and at least a portion of a second propeller of the plurality of propellers, which is different from the first propeller.

Description

CROSS-REFERENCE TO A RELATED REGISTRATION This application claims the priority and benefits of U.S. Application No. 16 / 923,939, filed on July 8, 2020, which is incorporated herein in its entirety by reference. AREA The field of the present invention relates generally to electric aircraft and in particular to the electrical power distribution for electric aircraft. BACKGROUND Advances in battery technology have enabled battery energy densities suitable for powering lightweight electric aircraft. Electric propulsion systems for electric aircraft, especially passenger aircraft, must be safe, lightweight, and efficient. Safety considerations sometimes conflict with the goals of weight reduction and high efficiency. For example, conventional power distribution systems often employ multiple battery sets and redundancies within the system to ensure there is no single point of failure; however, this redundancy increases inefficiencies and adds weight. Reconciling safety, aircraft weight, and efficiency presents a challenge in electric aircraft design. SUMMARY According to various embodiments, an electric aircraft comprises a plurality of electric drive units and a plurality of battery sets, each independently powering a different portion of the electric drive units. According to various embodiments, a first group of electric drive units is a group of rotors that provide lift for the aircraft, and a second group of electric drive units is a group of proprotors that can be tilted to provide lift in a lift position and forward thrust in a forward thrust position, with each battery set powering at least a portion of at least one rotor and at least a portion of one proprotor.According to various embodiments, the first group of electric drive units is arranged forward of the leading edge of a group of wings, and the second group of electric drive units is arranged aft of the trailing edge of the group of wings, such that each battery set supplies at least a portion of at least one of the electric drive units located forward of the wings and at least a portion of at least one of the electric drive units located aft of the wings. Should one battery set fail during flight, only the portion of the electric drive units supplied by that battery set is affected; the remaining electric drive units can operate normally because they are supplied by the other battery sets.According to various embodiments, each battery pack supplies energy to at least one part of at least one rotor and at least one part of at least one proprotor, so that in the event of deactivation of the battery pack or its power distribution bus during forward flight, only the forward power of the at least one part of the at least one proprotor is lost, since the at least one part of the at least one rotor is deactivated during forward flight and the remaining proprotor parts can continue to be operated with the adjustment of the control surfaces and the power from the remaining proprotor parts, which compensate for the lost proprotor parts.According to various embodiments, the battery sets that supply power to different parts of the electric drive units are not electrically connected to each other, so that no diodes are required to prevent current from flowing from one battery set to another, resulting in greater efficiency in power distribution and weight savings compared to architectures where the battery sets are arranged in parallel. According to some embodiments, an electric aircraft comprises a plurality of rotors for providing lift for vertical takeoff and landing; a plurality of proprotors that are tiltable between lift configurations for providing lift for vertical takeoff and landing and propulsion configurations for providing forward thrust for the aircraft; a first battery set for supplying at least a portion of a first rotor of the plurality of rotors and at least a portion of a first proprotor of the plurality of proprotors; a second battery set for supplying at least a portion of a second rotor of the plurality of rotors and at least a portion of a second proprotor of the plurality of proprotors; and a first electrical power bus that electrically connects the first battery set to at least a portion of the first rotor and at least a portion of the first proprotor.and a second electrical current bus that electrically connects the second battery set to at least a part of the second rotor and at least a part of the second proprotor, wherein the second electrical current bus is electrically isolated from the first electrical current bus. In each of these embodiments, the first rotor and the first proporator can be located on opposite sides of the aircraft. In each of these embodiments, the first rotor can only be supplied by the first battery set, and the first proporator is only supplied by the second battery set. In each of these embodiments, the first rotor can contain at least two motor parts, wherein the first battery set drives a first motor part of the at least two motor parts, and the second battery set drives a second motor part of the at least two motor parts. In each of these embodiments, an electrical circuit connecting the first battery set to the first rotor and the first proprotor can be free of diodes. In each of these embodiments, the first battery set can contain a plurality of batteries arranged in series, in parallel, or in a combination of series and parallel. In each of these embodiments, the first and second battery sets can be designed to generate more than 100 volts. In each of these embodiments, the electrical power of at least one of the first rotor and the first proprotor can be at least 10 kilowatts. In each of these configurations, the aircraft can be manned. In each of these embodiments, the aircraft can be a vertical take-off and landing aircraft. According to some unpatented embodiments, a method for powering an aircraft includes powering at least a part of a first rotor and at least a part of a first proprotor by means of a first battery set via a first electrical power bus that electrically connects the first battery set to the at least a part of the first rotor and the at least a part of the first proprotor; and powering at least a part of a second rotor and at least a part of a second proprotor by means of a second battery set via a second electrical power bus that electrically connects the second battery set to the at least a part of the second rotor and the at least a part of the second proprotor, wherein the second electrical power bus is electrically isolated from the first electrical power bus. In each of these embodiments, the first rotor and the first proporator can be located on opposite sides of the aircraft. In each of these embodiments, the method may further include providing lift to the aircraft during vertical takeoff via the first and second rotors and the first and second proporators, and providing forward thrust to the aircraft during cruise flight via the first and second proporators while the first and second rotors are deactivated. In each of these embodiments, the first rotor can only be driven by the first battery pack. In each of these embodiments, the first rotor can contain at least two motor parts, wherein the first battery set drives a first motor part of the at least two motor parts, and the second battery set drives a second motor part of the at least two motor parts. In each of these embodiments, an electrical circuit connecting the first battery set to the first rotor and the first proprotor can be free of diodes. In each of these embodiments, the first battery set can include a plurality of batteries arranged in series, in parallel, or in a combination of series and parallel. In each of these embodiments, the first and second battery sets can be designed to generate more than 100 volts. In each of these embodiments, the electrical power of the first rotor can be at least 10 kilowatts. In each of these configurations, the aircraft can be manned. According to various embodiments, an electric aircraft comprises a fuselage; at least one wing connected to the fuselage; a first plurality of electric drive units attached to the at least one wing and arranged at least partially forward of a leading edge of the at least one wing; a second plurality of electric drive units attached to the at least one wing and arranged at least partially aft of a trailing edge of the at least one wing; a first battery set for supplying at least part of a first electric drive unit of the first plurality of electric drive units and at least part of a first electric drive unit of the second plurality of electric drive units;a second battery set for supplying at least one part of a second electric drive unit of the first plurality of electric drive units and at least one part of a second electric drive unit of the second plurality of electric drive units; a first electric current bus that electrically connects the first battery set to the at least one part of the first electric drive unit of the first plurality of electric drive units and to the at least one part of the first electric drive unit of the second plurality of electric drive units;and a second electric current bus that electrically connects the second battery set to the at least one part of the second electric drive unit of the first plurality of electric drive units and to the at least one part of the second electric drive unit of the second plurality of electric drive units, wherein the second electric current bus is electrically isolated from the first electric current bus. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units and the first electric drive unit of the second plurality of electric drive units can be located on opposite sides of the aircraft. In each of these embodiments, the first plurality of electric drive units can contain tiltable proprotors and the second plurality of electric drive units can contain fixed rotors. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units can only be supplied by the first battery set. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units can contain at least two motor parts, wherein the first battery set supplies a first motor part of the at least two motor parts and the second battery set supplies a second motor part of the at least two motor parts. In each of these embodiments, a circuit connecting the first battery set to the first electric drive unit of the first plurality of electric drive units and the first electric drive unit of the second plurality of electric drive units can be free of diodes. In each of these embodiments, the first battery set can contain a plurality of batteries arranged in series, in parallel, or in a combination of series and parallel. In each of these embodiments, the first and second battery sets can be designed to generate more than 100 volts. In each of these embodiments, the electrical power of the first electric drive unit of the first plurality of electric drive units can be at least 10 kilowatts. In each of these configurations, the aircraft can be manned. In each of these embodiments, the aircraft can be a vertical take-off and landing aircraft. According to some unprotected embodiments, a method for supplying an aircraft includes supplying a first plurality of electric drive units, which are attached to at least one wing of the aircraft and are arranged at least partially forward of a leading edge of the at least one wing, by means of a first battery pack via a first electric power bus, which electrically connects the first battery pack to at least a part of the first electric drive unit of the first plurality of electric drive units and to the at least a part of the first electric drive unit of the second plurality of electric drive units;and supplying a second plurality of electric drive units, which are attached to the at least one wing and arranged at least partially rearward of a trailing edge of the at least one wing, by means of a second battery pack via a second electric current bus, which electrically connects the second battery pack to the at least part of the second electric drive unit of the first plurality of electric drive units and to the at least part of the second electric drive unit of the second plurality of electric drive units, wherein the second electric current bus is electrically isolated from the first electric current bus. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units and the first electric drive unit of the second plurality of electric drive units can be located on opposite sides of the aircraft. In each of these embodiments, the first plurality of electric drive units can contain tiltable proprotors and the second plurality of electric drive units can contain fixed rotors. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units can only be supplied by the first battery set. In each of these embodiments, the first electric drive unit of the first plurality of electric drive units can contain at least two motor parts, wherein the first battery set supplies a first motor part of the at least two motor parts and the second battery set supplies a second motor part of the at least two motor parts. In each of these embodiments, a circuit connecting the first battery set to the first electric drive unit of the first plurality of electric drive units and the first electric drive unit of the second plurality of electric drive units can be free of diodes. In each of these embodiments, the first battery set can contain a plurality of batteries arranged in series, in parallel, or in a combination of series and parallel. In each of these embodiments, the first and second battery sets can be designed to generate more than 100 volts. In each of these embodiments, the electrical power of the first electric drive unit of the first plurality of electric drive units can be at least 10 kilowatts. In each of these configurations, the aircraft can be manned. In each of these embodiments, the aircraft can be a vertical take-off and landing aircraft. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure is now described by way of example only and with reference to the accompanying drawings, in which the following applies: Fig. 1A shows a VTOL aircraft in a forward flight configuration according to various embodiments; Fig. 1B shows a VTOL aircraft in a takeoff and landing configuration according to various embodiments; Figs. 2A and 2B illustrate a power distribution architecture for supplying the electric propulsion units of an aircraft according to various embodiments; Fig. 3 is a block diagram of a circuit connecting a battery pack to a pair of electric propulsion units according to various embodiments; and Fig. 4 is a block diagram of part of the power distribution for an electric propulsion unit containing two partial motors according to various embodiments. DETAILED DESCRIPTION According to various embodiments, power distribution systems and unpatented methods for an electric aircraft involve supplying a plurality of the aircraft's electric propulsion units (EPUs) with a plurality of battery sets, each supplying a different portion of the EPUs using separate power distribution buses. For example, a first battery set supplies a first portion of the EPUs using a first power distribution bus, and a second battery set supplies a second portion of the EPUs using a second power distribution bus that is electrically isolated from the first. If the first battery set fails, only the first portion of the EPUs is without power; the second portion of the EPUs continues to be powered by the second battery set. The EPUs are sized such that the aircraft can continue controlled flight, at least without the first portion of the EPUs.By supplying different parts of the EPUs with different battery sets using different buses, a fault-tolerant power distribution can be achieved without the need for interconnected battery sets and the diodes required for such architectures, which can lead to higher power distribution efficiency and lower weight. According to various embodiments, the plurality of EPUs includes rotors designed to provide lift to the aircraft, such as during vertical takeoff and landing and hovering, which can be deactivated during cruise flight, as well as proprotors that provide lift to the aircraft and can tilt forward to provide forward thrust for forward flight, with the lift being provided by one or more wings of the aircraft. According to various embodiments, each battery pack supplies at least a portion of at least one rotor and at least a portion of at least one proprotor, such that if the battery pack or its power distribution bus is deactivated during forward flight, only the power to at least one portion of the at least one proprotor is lost. The other EPU(s) supplied by the lost battery pack, i.e.,The rotor(s) do not contribute to forward power, so their loss does not affect forward flight. The remaining propeller parts (powered by other battery sets) can continue to operate, with adjustments to the control surfaces and / or the power output of the remaining propeller parts compensating for the lost propeller parts. Thus, the impact of losing a battery set on forward flight can be minimized while ensuring fault tolerance without the increased weight associated with diodes and / or redundant power distribution buses. In various embodiments, each battery set powers the equivalent of one propeller (in addition to a certain proportion of the rotors), so the forward power loss for forward flight due to the loss of one battery set is only the equivalent of one propeller's power. According to various embodiments, the aircraft is an electric, vertical take-off and landing (VTOL or eVTOL) aircraft capable of vertical take-off and landing as well as hovering, thus offering the possibility of bringing passengers closer to their destination than would be possible with aircraft requiring a runway. According to various embodiments, the aircraft is an eVTOL fixed-wing aircraft. In various embodiments, the EPUs powered by a particular battery pack are selected to reduce destabilizing effects caused by a loss of power to the EPUs in the event of a battery pack failure. EPUs located on opposite sides of one or more axes of symmetry of the EPU array can be powered by the same battery pack to reduce roll, pitch, or yaw moments that may result from a loss of power to the EPUs powered by that battery pack. For example, EPUs located on both sides of the aircraft's longitudinal axis in the same relative position can be powered by a first battery pack, such that if one of the battery packs fails, only minimal roll moments will occur, since the thrust provided by the remaining EPUs will still be uniform around the longitudinal axis.Similarly, in some embodiments the EPUs are arranged forward and rearward of a group of wings, and EPUs on opposite sides of the wings and on opposite sides of the longitudinal axis can be powered by the same battery pack. According to various embodiments, the portion of the EPU powered by a battery pack can contain parts of a single EPU motor, such that one part of an EPU motor is powered by a first battery pack and another part of the EPU motor is powered by a second battery pack. For example, an EPU can contain two half-motors that can operate together under normal conditions to drive multiple blades that provide thrust to the aircraft, with one half-motor being powered by one battery pack and the other half-motor being powered by a different battery pack. In the event of a failure of one of the battery packs, the EPU remains operational at half power. A single battery pack can power partial motors of different EPUs, so that the impact of the loss of one battery pack is distributed among several EPUs that continue to operate at reduced power. The following description of the disclosure and embodiments refers to the accompanying drawings, which illustrate specific embodiments that can be implemented in practice. It is understood that other embodiments and examples can also be implemented in practice and modifications can be made without deviating from the scope of the disclosure. Additionally, the singular forms "ein," "eine," and "der," "die," "das" used herein also include the plural forms, unless the context clearly indicates otherwise. It is also understood that the term "and / or," as used herein, refers to and includes all possible combinations of one or more of the related listed elements. Furthermore, it is understood that the terms "contains," "containing," "comprises," and / or "comprehensive," when used herein, specify the presence of certain features, integers, steps, operations, elements, components, and / or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and / or groups thereof. As used herein, the term "proporator" refers to a variable-pitch propeller which can provide thrust for vertical lift and forward propulsion by varying the angle of attack of the propeller. As used herein, the term 'battery set' means any combination of electrically connected batteries (i.e., battery cells) and may include a variety of batteries arranged in series, parallel, or in a combination of series and parallel. Figures 1A and 1B illustrate a VTOL aircraft 100 in a travel configuration and a vertical take-off and landing configuration, respectively, according to various embodiments. Exemplary embodiments of a VTOL aircraft according to various embodiments are discussed in U.S. Patent Application No. 16 / 878,380 entitled "Vertical Take-Off and Landing Aircraft," filed on May 19, 2020, the entire contents of which are incorporated herein by reference. The aircraft 100 comprises a fuselage 102, wings 104 attached to the fuselage 102, and one or more tail stabilizers 106 attached to the rear of the fuselage 102. The aircraft 100 comprises a plurality of rotors 112 and a plurality of proprotors 114 (hereinafter collectively referred to as EPUs). The EPUs (112, 114) generally comprise an electric motor that drives a fan (a plurality of blades) and a motor controller for controlling / supplying the motor. As discussed further below with reference to Fig. 4, an EPU may comprise a plurality of sub-motors that can drive the fan independently and collectively and can be controlled by a plurality of separate motor controllers. The rotors 112 are mounted on the wings 104 and are designed to provide lift for vertical takeoff and landing. The proprotors 114 are mounted on the wings 104 and are tiltable between lift configurations, in which they provide a portion of the lift required for vertical takeoff and landing as well as hovering, as shown in Fig. 1B, and propulsion configurations, in which they provide forward thrust to the aircraft 100 for level flight, as shown in Fig. 1A. As used herein, a proprotor lift configuration refers to any proprotor orientation in which the proprotor thrust primarily provides lift to the aircraft, and a proprotor propulsion configuration refers to any proprotor orientation in which the proprotor thrust primarily provides forward thrust to the aircraft. According to various embodiments, the rotors 112 are designed exclusively for providing lift, with all propulsion being provided by the proprotors. Accordingly, the rotors 112 can be in fixed positions. During takeoff and landing, the proprotors 114 are tilted into lift configurations in which their thrust is directed downwards to provide additional lift. For forward flight, the proprotors 114 tilt from their lift configurations to their thrust configurations. In other words, the angle of attack of the proprotors 114 is varied from an angle where the proprotor thrust is directed downwards to provide lift during vertical takeoff and landing, as well as hovering, to an angle of attack where the proprotor thrust is directed backwards to provide forward thrust to the aircraft 100. The proprotors tilt about the axes 118, which are perpendicular to the forward direction of the aircraft 100. When the aircraft 100 is in full forward flight, lift can be provided entirely by the wings 104, and the rotors 112 can be shut down. The blades 120 of the rotors 112 can be locked in low-drag positions for cruise flight.In some embodiments, the rotors 112 each have two blades 120, which are locked in positions of minimum drag for cruise flight, with one blade directly in front of the other, as illustrated in Fig. 1A. In some embodiments, the rotors 112 have more than two blades. In some embodiments, the proprotors 114 have more blades 116 than the rotors 112. For example, the rotors 112 may each have two blades, as illustrated in Fig. 1A and Fig. 1B, and the proprotors 114 may each have five blades. According to various embodiments, the proprotors 114 may have between two and five blades. According to various embodiments, the aircraft includes only one wing 104 on each side of the fuselage 102 (or a single wing extending over the entire aircraft), and at least part of the rotors 112 are located aft of the wings 104 and at least part of the proprotors 114 are located forward of the wings 104. In some embodiments, all rotors 112 are located aft of the wings 104 and all proprotors are located forward of the wings 104. According to some embodiments, all rotors 112 and proprotors 114 are attached to the wings, i.e., no rotors or proprotors are attached to the fuselage. According to various embodiments, the rotors 112 are all located behind the wings 104, and the proprotors 114 are all located in front of the wings 104. According to some embodiments, all rotors 112 and proprotors 114 are arranged within the wing tips 109. According to various embodiments, the rotors 112 and the proprotors 114 are attached to the wings 104 by means of booms 122. The booms 122 can be located below or on top of the wings 104 and / or integrated into the wing profile. In various embodiments, one rotor 112 and one proprotor 114 are attached to each boom 122. The rotor 112 can be attached to a rear end of the boom 122, and a proprotor 114 can be attached to a front end of the boom 122. In some embodiments, the rotor 112 is fixed in position on the boom 122. In some embodiments, the proprotor 114 is attached to a front end of the boom 122 via a hinge 124.The proprotor 114 can be attached to the boom 122 in such a way that the proprotor 114 is aligned with the body of the boom 122 when it is in its propulsion configuration, forming a continuous extension of the front end of the boom 122, which minimizes drag for forward flight. According to various embodiments, the aircraft 100 may have only one wing on each side or a single wing extending over the entire aircraft. According to some embodiments, the at least one wing 104 is a high-wing monoplane attached to the upper surface of the fuselage 102. According to some embodiments, the wings include control surfaces, such as flaps and / or ailerons. According to some embodiments, the wings may have curved wingtips 109 to reduce drag during forward flight. According to some embodiments, the tail stabilizers 106 include control surfaces, such as one or more rudders, one or more elevators, and / or one or more combined rudders and elevators. The wing(s) may have any suitable shape. In some embodiments, the wings have a tapered leading edge 123, as shown, for example, in the embodiment of Fig. 1A. In some embodiments, the wings have a tapered trailing edge. Fig. 2A illustrates a power distribution architecture for supplying the EPUs (112, 114) of the aircraft 100 according to various embodiments. Although Figs. 1A-2A illustrate 12 EPUs (numbered 1-12 in Fig. 2A) mounted on the wings 104, the aircraft can have any number of EPUs according to various embodiments, including four, six, eight, ten, fourteen, eighteen, twenty, or more. The EPUs are powered by a plurality of battery sets 200. In the embodiment illustrated in Fig. 2A, there are six battery sets 200 numbered 1 to 6. Each battery set 200 supplies only a portion of the EPUs. In the illustrated embodiment, each battery set 200 supplies two EPUs. The grouping of battery sets and EPUs according to the embodiment illustrated in Fig. 2A is shown in Fig. 2B. Battery set 1 powers EPUs 1 and 12, battery set 2 powers EPUs 2 and 11, and so on.Each battery pack 200 is connected to its respective part of the EPUs via a dedicated power distribution bus, e.g., buses 202 and 204. Therefore, the power distribution bus 202 of battery pack 1 is not electrically connected to the power distribution bus 204 of battery pack 2. Because the 200 battery sets are electrically isolated from one another, an electrical failure in one battery set or its power distribution system does not affect the operation of the other EPUs and battery sets. Only the EPUs powered by the failed battery or power distribution system are affected. Thus, there is no single point of failure in the aircraft's power supply. Since the battery sets and power distribution circuits are isolated from each other, diodes are also not required to prevent current from flowing from one battery set to another. This can result in significant weight savings and higher efficiency compared to systems where the battery sets are connected in parallel. According to various embodiments, the individual EPUs powered by a particular battery pack can be selected to reduce destabilization effects caused by a loss of power to the EPUs in the event of a battery pack failure. According to various embodiments, EPUs located on opposite sides of one or more axes of symmetry of the array of EPUs can be powered by the same battery pack to reduce roll, pitch, or yaw moments that may be caused by a loss of power to the EPUs powered by that battery pack.For example, EPUs located on both sides of the longitudinal axis 280 of the aircraft in the same relative position can be powered by a first battery set, so that if one of the battery sets fails, only minimal roll moments occur, since the thrust provided by the remaining EPUs is maintained uniformly around the longitudinal axis. Similarly, in some embodiments, a group of EPUs is arranged at least partially forward of the leading edge of a pair of wings and a group of EPUs is arranged at least partially aft of the trailing edge of the pair of wings, and EPUs on opposite sides of the wings and on opposite sides of the longitudinal axis 280 can be powered by the same battery set, so that minimal roll and pitch moments occur in the event of battery set failure (as shown in Fig. 2A). According to various embodiments, each battery set 200 supplies at least a portion of the at least one proprotor 114 and at least a portion of the at least one rotor 112. In the embodiment of Fig. 2A, rotors and proprotors at opposite positions are driven by the same battery set 200. Thus, the outermost proprotor 114 on the left side of the fuselage 102 of the aircraft (EPU 1 in Fig. 2A) is supplied by the same battery set (battery set 1 in Fig. 2A) as the outermost rotor 112 on the right side of the fuselage 102 (EPU 12). Similarly, the other pair of outermost EPUs (EPU 6 and EPU 7 in Fig. 2A) is supplied by the same battery set (battery set 6). The groupings need not be limited to EPUs at exactly opposite positions. For example, EPU 1 can be grouped with EPU 11 instead of EPU 12. The number of EPUs powered by a given battery set can be greater than two. For example, in some embodiments, the number of EPUs per battery set can be three, four, five, six, or another suitable proportion of the total number of EPUs. According to various embodiments, there can be a different number of EPUs within each group. For example, one group can have two EPUs (two EPUs powered by one battery set), while another group can have four EPUs (four EPUs powered by a different battery set). The number of battery sets can be up to two. In various embodiments, the number of battery sets is at least three, at least four, at least five, at least six, at least seven, at least eight, or more. Fig. 3 is a block diagram of a circuit connecting a battery pack 300 to a pair of EPUs 302, 304, according to various embodiments. EPU 302 can be, for example, EPU 1 of Fig. 2A, and EPU 304 can be, for example, EPU 12 of Fig. 2A. The battery pack 300 is connected to the EPUs 302, 304 via a power distribution bus 306. A plurality of fuses is provided to protect the components in the event of an electrical failure. Two fuses 308 and 310 are provided to disconnect the EPUs 302 and 304, respectively, if a current surge associated with the respective EPU 302, 304 occurs. A fuse 312 is located immediately downstream of the battery pack 300. Fuse 312 has a higher amperage rating than fuses 308 and 310 because it supplies power to both EPUs. In some embodiments, a small fuse 314 is located between the battery pack and the charging circuit (not shown). According to various embodiments, a contactor 316 can be provided to connect / disconnect the positive terminal of the battery pack 300 to / from the EPUs. According to various embodiments, the contactor 316 can be used to disconnect the EPUs from the power supply, e.g., when the aircraft is on the ground. According to various embodiments, the contactor 316 is operated manually, e.g., via a manual switch located in the aircraft cockpit. In some embodiments, a similar contactor 318 is also provided at the negative terminal. In some embodiments, the EPUs, or at least some of the EPUs, contain multiple motor stages, each independently powered by different battery sets. This means that if one battery set fails, only a portion of the EPUs loses power, and the EPU can continue to operate at reduced power. Figure 4 is a block diagram of part of the power distribution for an EPU 400, which contains two sub-motors – 402A and 402B. The EPU 400 can be a rotor, such as rotor 112 of Figure 1A, or a proprotor, such as proprotor 114 of Figure 1A. The two sub-motors, 402A and 402B, can be operated independently to drive the fan blades 404 via shaft 406, and can be operated simultaneously to drive the fan blades 404 at higher power. The sub-motors 402A and 402B are driven by their own motor controllers 408A and 408B respectively.Sub-motor 402A and motor control 408A are powered by battery pack 450 via power distribution bus 460, while sub-motor 402B and motor control 408B are powered by battery pack 452 via power distribution bus 462. Sub-motor 402A, motor control 408A, distribution bus 460, and battery pack 450 are electrically isolated from sub-motor 402B, motor control 408B, distribution bus 462, and battery pack 452. Therefore, an electrical failure affecting sub-motor 402A does not affect sub-motor 402B, and vice versa. Thus, the EPU 400 can continue to operate, albeit at reduced power, even if one of battery packs 450 or 452 fails. According to various embodiments, a battery pack can power sub-motors of opposing EPUs. For example, as shown in Fig. 2A, the first battery pack 1 can power a first sub-motor of EPU 1, a first sub-motor of EPU 12, a first sub-motor of EPU 6, and a first sub-motor of EPU 7. Thus, in the event of a failure of battery pack 1, both the rotors and the propellers at the same relative position on opposite sides of the aircraft lose at least half of their maximum available power, but remain operational. The battery packs for powering the EPUs can be located at any suitable location on the aircraft, including the fuselage and / or wings. The number and power of the EPUs can be selected according to the desired performance parameters (e.g., target payload, airspeed, and altitude). According to various embodiments, the maximum rated power of one or more EPUs is 500 kilowatts or less, preferably 200 kilowatts or less, and more preferably 150 kilowatts or less. According to some embodiments, the maximum rated power of one or more EPUs is at least 10 kilowatts, preferably at least 20 kilowatts, and more preferably at least 50 kilowatts. The aircraft can have an equal number of rotors and propellers, a greater number of propellers, or a greater number of rotors. According to various embodiments, each battery pack is designed for a maximum stored energy of at least 1 kilowatt-hour, or preferably at least 10 kilowatt-hours, and / or a maximum stored energy of at most 200 kilowatt-hours, preferably at most 100 kilowatt-hours, more preferably at most 75 kilowatt-hours, and even more preferably at most 50 kilowatt-hours. According to various embodiments, the battery packs are designed such that their collective maximum stored energy is at least 1 kilowatt-hour, or preferably at least 10 kilowatt-hours, and / or their maximum stored energy is at most 200 kilowatt-hours, preferably at most 100 kilowatt-hours, more preferably at most 75 kilowatt-hours, or even more preferably at most 50 kilowatt-hours.According to various embodiments, at least some of the battery sets provide a voltage of at least 100 volts, at least 500 volts, or at least 1000 volts when fully charged. According to various embodiments, at least some of the battery sets provide a maximum of 2000 volts, at most 1500 volts, at most 1000 volts, or at most 500 volts when fully charged. According to some embodiments, the maximum nominal voltage is between 500 and 1000 volts, preferably between 600 and 800 volts, or even more preferably between 650 and 750 volts. According to various embodiments, the EPUs are sized to compensate for the loss of some EPUs due to the failure of a battery pack, in accordance with the principles discussed above. For example, if two EPUs are lost due to the failure of the battery pack powering them, the remaining EPUs and their associated battery packs can be sufficiently sized to provide additional thrust to at least partially compensate for the thrust loss of the deactivated EPUs. Aircraft based on the principles discussed above can be designed to carry at least one person and up to ten people, preferably up to six people, and more preferably up to four people. According to some embodiments, the aircraft is designed to be controlled and includes controls. In some embodiments, the aircraft is designed to operate autonomously without a pilot on board and with or without one or more passengers. According to some embodiments, the aircraft is designed to carry up to six people (for example, a pilot and up to five passengers) up to 75 miles at a cruising speed of up to 150 miles per hour at an altitude of up to 3,000 feet above ground level. In some embodiments, the aircraft is designed for five people, for example, a pilot and four passengers. According to various embodiments, the maximum range on a single battery charge is 25 miles, 50 miles, 75 miles, 100 miles, or 200 miles. According to various embodiments, the rotors 112 and / or the proprotors 114 are designed to have a relatively low peak speed in order to reduce the amount of noise generated by the aircraft. In some embodiments, the peak speed of the rotor blades in hovering flight is approximately Mach 0.4. According to various embodiments, the diameter of the rotor and / or proprotor blades is in the range of 1 to 5 meters, preferably in the range of 1.5 to 2 meters. According to various embodiments, the wingspan is in the range of 10 to 20 meters, preferably in the range of 15 to 16 meters. According to various embodiments, the length of the aircraft is in the range of 3 to 20 meters, preferably in the range of 5 to 15 meters, and even more preferably in the range of 6 to 10 meters. According to various embodiments, the aircraft is operated during takeoff and landing by arranging the proprotors in lift configurations, thus providing the aircraft with the required lift via the combined lift generated by the rotors and proprotors. According to various embodiments, the proprotors can be maintained in predetermined lift configurations during vertical takeoff and landing and / or hovering, which may be the same for all proprotors or different for different proprotors. According to various embodiments, the tilt of at least some proprotors can be actively adjusted during takeoff and landing and / or hovering to ensure the required stability and / or maneuverability.According to some embodiments, the tilt of at least one proprotor during takeoff and landing and / or hovering is actively controlled by the flight control system to generate yaw moments. According to various embodiments, each rotor and / or proprotor can be individually controlled by the flight control system according to its various operational degrees of freedom. In some embodiments, the rotor's only degree of freedom is its rotational speed. In others, the pitch angle of the rotor blades can be collectively adjusted, providing an additional degree of freedom. In other embodiments, the degrees of freedom of at least some of the proprotors include the proprotor rotational speed, the collective pitch angle of the blades, and the proprotor tilt angle. In other embodiments, each of these degrees of freedom can be actively controlled by the flight control system during takeoff and landing (either autonomously or in response to pilot commands) to ensure appropriate stability and maneuverability. Once the aircraft has reached a sufficient altitude to begin forward flight, the proprotors begin to tilt forward toward their propulsion configurations, so that their thrust provides a combination of lift and thrust, with the lift component decreasing as the proprotors tilt further toward their propulsion configurations. The rotors can remain active, at least for part of the time the proprotors are tilted forward, to continue providing rotor-assisted lift. Once the forward airspeed is high enough for the wings to provide sufficient lift to maintain the aircraft's altitude, the rotors can be deactivated at any time. As discussed above, the rotor blades can be locked in a low-drag position. During cruise flight, the rotors remain deactivated. The wing control surfaces and / or tail stabilizers can be used in the conventional manner to improve the aircraft's maneuverability and stability. According to some embodiments, in the event of a battery pack being lost during forward flight, resulting in the loss of power to the propellers powered by that pack, the aircraft can compensate for this loss by using the control surfaces and / or by adjusting the power output of the unaffected portion of the propellers. According to some embodiments, the pitch of at least some proprotors can be actively controlled to provide additional stability and / or maneuverability. In some embodiments, the pitch of at least some of the proprotors is actively controlled during takeoff and landing and / or hovering. In some embodiments, the pitch of the proprotors is fixed (i.e., not variable) during cruise flight. According to some embodiments, the pitch of the outermost proprotors can be actively and independently controlled during vertical takeoff and landing and / or hovering to provide yaw moments when required. According to various embodiments, the EPUs (rotors and propellers) can be supplied according to the power distribution architecture described herein. For example, an unpatented method for supplying an aircraft involves supplying, via a first battery pack, a first plurality of electric drive units, which are mounted on at least one wing of the aircraft and arranged at least partially forward of a leading edge of the at least one wing, via a first electrical power bus that electrically connects the first battery pack to at least a portion of the first electric drive unit of the first plurality of electric drive units and to at least a portion of the first electric drive unit of the second plurality of electric drive units.The unprotected method also includes supplying, by means of a second battery set, a second plurality of electric drive units, which are attached to the at least one wing and arranged at least partially rearward of a trailing edge of the at least one wing, via a second electric current bus, which electrically connects the second battery set to the at least part of the second electric drive unit of the first plurality of electric drive units and to the at least part of the second electric drive unit of the second plurality of electric drive units, wherein the second electric current bus is electrically isolated from the first electric current bus. According to various unprotected embodiments, a method for powering an aircraft includes supplying, via a first battery pack, at least a portion of a first rotor and at least a portion of a first proprotor through a first electrical bus that electrically connects the first battery pack to the at least portion of the first rotor and the at least portion of the first proprotor. The unprotected method also includes supplying, via a second battery pack, at least a portion of a second rotor and at least a portion of a second proprotor through a second electrical bus that electrically connects the second battery pack to the at least portion of the second rotor and the at least portion of the second proprotor, wherein the second electrical bus is electrically isolated from the first electrical bus. According to various embodiments, if a battery pack or the power distribution to that battery pack should fail during flight, such as during vertical takeoff or landing, hovering, or forward flight, only the EPUs powered by that battery pack are deactivated. The remaining EPUs, powered by other battery packs that are electrically isolated from the deactivated battery pack, continue to operate. According to various embodiments, the power output of at least some of the unaffected EPUs can be increased to compensate for the thrust loss of the deactivated EPUs. In various embodiments, the battery sets supply different motor sections of the same EPU, so that in the event of the loss of one of the battery sets or its power distribution, the affected EPUs can continue to operate at reduced power. In various embodiments, the power of the unaffected motor section can be increased and / or the power of the unaffected EPUs can be increased to compensate for the loss of thrust from the deactivated motor sections. The foregoing description has been provided for illustrative purposes with reference to specific embodiments. However, the above illustrative discussions do not claim to be exhaustive, nor do they limit the invention to the exact forms disclosed. Many modifications and variations are possible with regard to the teachings above. The embodiments have been selected and described to best explain the principles of the techniques and their practical applications. This enables other skilled persons to make optimal use of the techniques and the various embodiments with different modifications suitable for their respective intended uses. Although the disclosure and the examples have been fully described with reference to the accompanying figures, it should be noted that various changes and modifications will be apparent to the person skilled in the art. Such changes and modifications are to be understood as falling within the scope of the disclosure and the examples defined in the claims. Finally, the entire disclosure of the patents and publications referenced in this application is hereby incorporated by reference. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature US 16 / 923,939

[0001] US 16 / 878,380

[0057]

Claims

An electric aircraft comprising: a fuselage; one or more wings mounted on the fuselage; a plurality of propellers pivotable between lift and forward propulsion configurations; and a plurality of battery packs, wherein at least two of the plurality of battery packs are configured to power: at least a portion of a first propeller of the plurality of propellers and at least a portion of a second propeller of the plurality of propellers, which is different from the first propeller. The electric aircraft according to claim 1, wherein the electric aircraft comprises two wings extending on opposite sides of the fuselage. The electric aircraft according to claim 1, wherein the plurality of proprotors are arranged to tilt about axes perpendicular to the forward direction of the electric aircraft. The electric aircraft according to claim 1, wherein each of the plurality of proprotors has five blades. The electric aircraft according to claim 1, wherein at least two of the plurality of proprotors are arranged in front of the one or more wings. The electric aircraft according to claim 2, wherein at least one proprotor of the plurality of proprotors is attached to each of the two wings. The electric aircraft according to claim 6, wherein each of the multiple battery packs is configured to supply energy only to proprotors of the plurality of proprotors that are attached to one of the two wings. The electric aircraft according to claim 6, wherein each of the multiple battery packs is configured to supply energy to at least one of the proprotors mounted on one of the wings and at least one of the proprotors mounted on the other wing. The electric aircraft according to claim 1, wherein the at least two battery packs of the plurality of battery packs are configured to supply energy to the part of the first proprotor of the plurality of proprotors and the part of the second proprotor of the plurality of proprotors via dedicated power supply buses. The electric aircraft according to claim 1, wherein each of the multiple battery packs is configured to supply energy to different parts of only one of the plurality of proprotors. The electric aircraft according to claim 1, wherein each proprotor of the plurality of proprotors is configured to be powered by at least two battery packs of the plurality of battery packs. The electric aircraft according to claim 1, further comprising: a plurality of contactors configured to electrically isolate the plurality of proprotors from the plurality of battery packs. The electric aircraft according to claim 1, further comprising: a plurality of fuses configured to electrically isolate the plurality of proprotors from the plurality of battery packs.

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