Electric powertrain architecture and fault-tolerant vtol aircraft using the architecture

Abstract

A power system having a battery architecture for enhanced reliability of electric motors suitable for use in flying machines. For example, in a system having six or more motors, separate batteries can be used to power subsets of two or more motors. Each motor can be powered by two or more subsets of batteries, allowing for mitigation of motor failure. In the event of a motor failure in a vertical takeoff or landing mode, power can be diverted to other motors to continue proper attitude control and provide sufficient thrust. In the event of a failed motor, a second motor offset from the failed motor can be powered down to facilitate attitude control.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 678,275, filed May 31, 2018, by Bevelt et al., which is incorporated herein by reference in its entirety. Invention Field

[0003] This invention relates to electrically driven flight, specifically to the power system of an electric motor used on aerial vehicles. Brief description of the attached diagram

[0005] Figures 1A-1D It is a VTOL aircraft in a hovering configuration according to some embodiments of the present invention.

[0006] Figures 1E-1H It is a VTOL aircraft in a forward-flying configuration according to some embodiments of the present invention.

[0007] Figures 1I-1K It is a VTOL aircraft that transitions from a forward-flying configuration to a vertical takeoff and landing configuration according to some embodiments of the present invention.

[0008] Figure 2A This is the layout of a flight system with a ring architecture according to some embodiments of the present invention.

[0009] Figure 2B This is a layout for identifying the motor positions in a ring-shaped architecture according to some embodiments of the present invention.

[0010] Figure 2C This is a layout of the battery location according to some embodiments of the present invention.

[0011] Figure 3 This is a motor power diagram according to some embodiments of the present invention.

[0012] Figure 4 This is a fault scenario layout according to some embodiments of the present invention.

[0013] Figure 5 This is a fault compensation layout according to some embodiments of the present invention.

[0014] Figure 6 This is a fault compensation layout according to some embodiments of the present invention.

[0015] Figure 7 This is a power architecture layout according to some embodiments of the present invention.

[0016] Figure 8 These are battery discharge diagrams according to some embodiments of the present invention.

[0017] Figure 9 is a flight control system architecture layout according to some embodiments of the application.

[0018] Figure 10 illustrates a flight control software architecture according to some embodiments of the application.

[0019] Figure 11A is a layout of a flight power system with dual architecture according to some embodiments of the application.

[0020] Figure 11B is a layout of a flight power system with dual architecture according to some embodiments of the application.

[0021] Figure 11C is a layout of a flight power system with dual architecture with motor failure according to some embodiments of the application.

[0022] Figure 11D is a layout of a flight power system with dual architecture with battery failure according to some embodiments of the application.

[0023] Figure 12 is a layout of a flight power system with hexagram architecture according to some embodiments of the application.

[0024] Figure 13 is a layout of a flight power system with star architecture according to some embodiments of the application.

[0025] Figure 14 is a layout of a flight power system with mesh architecture according to some embodiments of the application.

[0026] Figures 15A-15C represents information about battery failure operation according to some embodiments of the application.

[0027] SUMMARY

[0028] A power system suitable for use in a flying machine having a power system architecture for enhanced reliability of electric motors. For example, in a system having six or more motors, separate batteries can be used to power subsets of two or more motors. Each motor can be powered by two or more subsets of batteries, allowing for mitigation of motor failure. Each motor can have two or more sets of windings, with each winding powered by a different battery. In forward flight mode or vertical takeoff and landing mode, in the event of a failed winding, a failed battery, or a failed motor, power lines can be automatically changed to continue proper attitude control and provide sufficient thrust. In the event of a failed motor, a second motor offset from the failed motor can be powered down to facilitate attitude control.

[0029] DETAILED DESCRIPTION

[0030] In some aspects, a flying machine can use bladed propellers driven by electric motors to provide thrust during takeoff. The propeller / motor units can be referred to as propulsion assemblies. In some aspects, the wings of the flying machine can be rotated with the leading edge facing upward, such that the propellers provide vertical thrust for takeoff and landing. In some aspects, the motor-driven propeller units on the wings can themselves be rotated relative to the fixed wings, such that the propellers provide vertical thrust for takeoff and landing. Rotation of the motor-driven propeller units can allow for changes in direction of thrust by rotating both the propeller and the electric motor, thus not requiring any gimbaling about or through a rotational joint, or other methods.

[0031] In some aspects, a flying machine according to embodiments of the invention takes off from the ground with vertical thrust from rotor assemblies that have been deployed into a vertical configuration. As the flying machine begins to gain flying altitude, the rotor assemblies can begin to tilt forward in order to begin accelerating forward. As the flying machine gains forward speed, the airflow over the wings creates lift such that the rotors become less important and then do not need to be used to maintain flying altitude. Once the flying machine has reached sufficient forward speed, some or all of the blades used to provide vertical thrust during takeoff can be stowed along their nacelles. In some aspects, all of the propulsion assemblies used for vertical takeoff and landing are also used during forward flight. The nacelles supporting the propulsion assemblies can have recesses such that the blades can be nested in the recesses, greatly reducing the drag of the stowed rotor assemblies.

[0032] After takeoff, the flying machine will begin the transition to forward flight by articulating the propellers from a vertical thrust orientation to a position that includes horizontal thrust elements. As the flying machine begins to move forward at a speed, lift will be generated by the wings, thus requiring less vertical thrust from the rotors. As the propellers are articulated further toward the forward flight, horizontal thrust configuration, the flying machine gains more speed.

[0033] In a first vertical configuration according to some embodiments of the application, as seen in the vertical takeoff configuration in Figures 1A-1D In this configuration, the propulsion assemblies are positioned for vertical propulsion. The flying machine body 201 supports left wing 202 and right wing 203. The motor-driven rotor assemblies 206 along the wings can include electric motors and propellers that are adapted to be articulated from a forward flight configuration to a vertical configuration with a deployment mechanism that can reside in a nacelle body, and deploy the motors and propellers when all or most of the nacelle remains in place attached to the wings. In some aspects, the propeller blades can be stowed and nested into the nacelle body. The motor-driven rotor assemblies 207 at the wing tips can be deployed from a forward flight configuration to a vertical takeoff and landing configuration along a pivot axis, with the nacelle and electric motors and propellers deployed in unison. Although each wing is illustrated with one mid-span propulsion assembly and one wing tip propulsion assembly, in some aspects, there can be more mid-span propulsion assemblies.

[0034] The flying machine body 201 extends rearward, also attached to a raised rear stabilizer 204. The rear stabilizer has rear propulsion assemblies 205 attached to it. The motor-driven rotor assemblies 205 at the tips of the rear stabilizer can be deployed from a forward flight configuration to a vertical takeoff and landing configuration along a pivot axis, with the nacelle and electric motors and propellers deployed in unison.

[0035] As seen in the top view in Figure 1D The propulsion assemblies are positioned on two axes at different distances from the center of mass of the flying machine. Attitude control during vertical takeoff and landing can be manipulated by varying the thrust in each of the propulsion assembly locations. In the event of a motor failure during vertical takeoff or landing, and especially in the event of a motor failure at the outboard wing propulsion assemblies, the attitude of the flying machine can be maintained by implementing the fault tolerance strategies described herein.

[0036] The aerial vehicle 200 has two side-by-side passenger seats and landing gear under the body 201. Although two passenger seats are illustrated, other numbers of passengers can be accommodated in different embodiments of the invention.

[0037] Figures 1E-1H The aerial vehicle 200 is illustrated in a forward flight configuration. In this configuration, the propulsion assemblies are positioned to provide forward thrust during horizontal flight. As Figure 1H As seen in FIG. 2, in the forward flight configuration, the center of mass of the motors and propellers can be forward of the leading edge of the wings. As Figure 1G As seen in FIG. 2, the propulsion assemblies 205 on the rear stabilizers 204 can be at different heights than the propulsion assemblies 206, 207 on the wings. In the event of a motor failure during forward flight, the attitude of the aircraft can be maintained by implementing the fault-tolerant strategies described herein.

[0038] In some aspects, all or a subset of the propulsion assemblies mounted on the wings can be adapted for use in the forward flight configuration, while other propellers mounted on the wings can be adapted to be fully retracted during conventional forward flight. The aerial vehicle 200 can have two propulsion assemblies on the right wing 203 and two propulsion assemblies on the left wing 202. The inboard propulsion assemblies on each wing can have rotors 206 mounted on the wings that are adapted to flip up to a deployed position for vertical takeoff and landing, move rearward toward a retracted position during transition to forward flight, and then have the blades of these rotors 206 retracted and nested during forward flight. The outboard propulsion assemblies 207 can be uniformly pivoted from a horizontal thrust configuration to a vertical thrust configuration.

[0039] Similarly, each rear stabilizer 204 can have propulsion assemblies mounted to it, both of which are adapted for use during vertical takeoff and landing mode and transition mode. In some aspects, all of the propulsion assembly designs are identical, with a subset used for forward flight with the main blades of the propulsion assemblies. In some aspects, all of the propulsion assembly designs are identical, with all of the propellers used for forward flight. In some aspects, there can be different numbers of propulsion assembly units mounted to the rear stabilizers 204.

[0040] The motors driving the propulsion assemblies 206, 207 mounted on the wings and the motors driving the propulsion assemblies mounted on the rear stabilizers can each have two sets of windings. In some aspects, both sets of windings are energized during flight. In some aspects, each winding of the motor is powered by a different battery circuit. In some aspects, each motor can have more than two sets of windings.

[0041] In some embodiments, the electric motors of the flying instrument are powered by rechargeable batteries. The use of multiple batteries driving one or more power buses enhances reliability in the event of a single battery failure. In some embodiments, the batteries reside in a holder within the instrument body with an adjustable position so that the balance of the instrument can be adjusted according to the weight of the pilot. Figure 2A Figure illustrates a battery position layout for a six-battery system, according to some embodiments of the present application.

[0042] In some embodiments, as Figure 2A illustrated in FIG. 1, a high-reliability power system 10 for an electrically powered vertical takeoff and landing aircraft has six motors and six batteries in a ring architecture. In this exemplary configuration, there are six motors and six batteries. Each of the batteries provides power to two motors, and each motor receives power from two batteries. Figure 2B Figure illustrates the layout of the six motors on a VTOL aircraft in an exemplary embodiment using six propulsion assemblies and six batteries. Figure 2C Figure illustrates the layout of the six batteries in a VTOL aircraft in an exemplary embodiment using six propulsion assemblies and six batteries. In the exemplary ring embodiment, there are six batteries and six motors. Each of the motors is powered by two independent batteries. The different positions 30 of the batteries also enhance the reliability and fault tolerance of the power system architecture. Each battery powers two independent motors. In some aspects, each of the motors is wound with two sets of windings, and each set of windings receives power from a different battery. As discussed below with reference to Figure 7 Figure 2, each of the six batteries supplies two power inverters 31, for a total of 12 power inverters. The nominal voltage of the batteries is 600V. Each of the six propulsion motors has two sets of windings, with each motor being powered by two inverters, one for each set of windings. The two inverters powering a single motor are each supplied with power by a different battery.

[0043] In the exemplary six-motor six-battery embodiment 10, the first motor 11 is coupled to the sixth battery 26 and the first battery 21. The second motor 12 is coupled to the first battery 21 and the second battery 22. The third motor 13 is coupled to the second battery 22 and the third battery 23. The fourth motor 14 is coupled to the third battery 23 and the fourth battery 24. The fifth motor 15 is coupled to the fourth battery 24 and the fifth battery 25. The sixth motor 16 is coupled to the fifth battery 25 and the sixth battery 26. In a nominal operating scenario, each battery splits its power distribution equally between the two motors to which it is coupled, and each motor receives an equal amount of power from each battery to which it is coupled.

[0044] The fault-tolerant aspects of the power system architecture according to embodiments of the application are adapted to withstand and respond to at least the following faults: failure of a battery; failure of a motor; or failure of a motor inverter.

[0045] Figure 3 In the six-motor embodiment, the bar graph of the power required by individual motors 40 (with a bar pair for each mode of operation). The blue vertical bars (to the left of the bar pair for each mode) illustrate the nominal (normal) operating power of each motor for the five different flight phases (i.e., hover 41, vertical ascent 42, vertical descent 43, cruise climb 44, and cruise 45). The hover, vertical ascent, and vertical descent modes are VTOL modes in which the motors are rotated to a vertical thrust position, as seen in Figures 1A-1D The cruise climb and cruise phases are in which the motors are in a forward flight position, as seen in Figures 1E-1H The red vertical bars (to the right of the bar pair for each mode) represent emergency phase operation, as discussed below.

[0046] As seen in Figure 3 the illustrative embodiment of the six-motor, six-battery ring architecture system operates each motor at approximately 60 kW in the VTOL mode during nominal conditions. This 60 kW is compared to the maximum available power of about 150 kW. However, in the event of a motor failure, more power can be diverted to the remaining motors to maintain attitude control and flight altitude control, as discussed further below.

[0047] Figure 4 A potential failure mode 60 is illustrated in which the first motor fails. As seen in the motor layout represented, the loss of the first motor 11 represents a loss of thrust at the far port motor, which will have a significant impact on the attitude of the aircraft. The flight computer can immediately perceive at least two things: first, that the motor has stopped drawing current; second, that a disturbance to the attitude of the aircraft has occurred. To maintain balance in the aircraft, the flight control computer will reduce the power to the opposing motor as needed. In this example, as seen in Figure 5 the power to the fourth motor 14 will be reduced. The loss of lift due to the shutdown of two motors requires the remaining four motors to employ more power and deliver more lift. Figure 6 How the increased load demand in the second, third, fifth, and sixth motors is satisfied by distributing more power from the batteries is illustrated. Looking again at Figure 3, the red vertical bar illustrates the power delivery required by the motor failure and thus the relative motor stall. In some aspects, the de-energizing of the fourth motor and the power increase of the second, third, fifth, and sixth motors can occur simultaneously. In some aspects, the de-energizing of the fourth motor and the power increase of the second, third, fifth, and sixth motors can occur sequentially.

[0048] As Figure 6 As seen in FIG. 11, in the event of a failure of the first motor 11 and de-energizing of the fourth motor 14 to balance the aircraft, the first battery 21 now delivers power to only the second motor 12. Likewise, the third battery delivers power to only the third motor, the fourth battery delivers power to only the fifth motor, and the sixth battery delivers power to only the sixth motor. The second battery delivers power to both the second and third motors, and the fifth battery delivers power to both the fifth and sixth motors. Although illustrated as running the fourth motor down to 0% power, in some aspects, the cross motor can run at a low level, for example in the range of 0-20% of nominal power. Since the first and sixth batteries are providing power to only a single motor, and since the third and fourth batteries are primarily delivering power to only a single motor, these batteries will provide more current 61 to their respective windings of the second, third, fifth, and sixth motors. The second and fifth batteries will split evenly between their adjacent motors. In the event of a failure of the first motor 11 and de-energizing of the fourth motor 14 to balance the aircraft, the first battery 21 now delivers power to only the second motor 12. Likewise, the third battery delivers power to only the third motor, the fourth battery delivers power to only the fifth motor, and the sixth battery delivers power to only the sixth motor. The second battery delivers power to both the second and third motors, and the fifth battery delivers power to both the fifth and sixth motors. Although illustrated as running the fourth motor down to 0% power, in some aspects, the cross motor can run at a low level, for example in the range of 0-20% of nominal power. Since the first and sixth batteries are providing power to only a single motor, and since the third and fourth batteries are primarily delivering power to only a single motor, these batteries will provide more current 61 to their respective windings of the second, third, fifth, and sixth motors. The second and fifth batteries will split evenly between their adjacent motors. Figure 6 In the failure scenario illustrated in FIG. 11, each battery can output the same amount of power, but two batteries split their power delivery, and four batteries provide (or substantially provide) power to only a single motor. In this emergency mode, the increased load demand of the motors is shared through the battery architecture to utilize the available energy on the aircraft. While one motor has been disabled and a second motor has been de-energized to mitigate attitude control issues, each battery is still using and delivering power.

[0049] In some embodiments, a vertical takeoff and landing aircraft has an autonomous attitude control system adapted to withstand power link failures or complete motor failures in a multi-battery system through load sharing to better equalize battery discharge levels. In some aspects, each motor is driven on multiple complementary sets of windings, where each set of windings uses a different load link and is driven by a different battery. Figure 7is an illustrative embodiment of an electrical system power architecture for a six-motor, six-battery aircraft. Each of the six batteries 201 supplies two power inverters, for a total of 12 power inverters 202. The nominal voltage of the batteries is 600V. Each of the six propulsion motors 203 has two sets of windings, with each motor being powered by two inverters, one for each set of windings. The two inverters that power a single motor are each supplied with power from a different battery. In addition to supplying power to the motor inverters, the batteries also supply power to the rotor deployment mechanism 204 (nacelle tilt actuators) that is used to deploy and stow the rotors during various flight modes (vertical takeoff and landing configuration, forward flight configuration, and transitions between them).

[0050] The flight computer 205 monitors the current from each of the twelve motor inverters 202 that supply power to the sets of twelve windings in the six motors 203. The flight computer 205 can also control the motor current supplied to each of the 12 sets of windings of the six motors. In some embodiments, the batteries 201 also supply power to the blade pitch motors and position encoders of the variable pitch propellers 206. The batteries also supply power to the control surface actuators 207 that are used to position various control surfaces on the aircraft. The blade pitch motors and control surface actuators 207 can operate by receiving power through DC-DC converters 208, for example stepping down the voltage from 600V to 160V. A suite of avionics 209 can also be coupled to the flight computer. A battery charger 210 can be used to charge the batteries 201, and the battery charger can be external to the aircraft and ground-based.

[0051] In the event of a fault, such as a failure of a motor or of the power link to a motor, compensation for the power distribution from the various batteries to the various motors can be accomplished autonomously and on-board the aircraft, as described above. For example, the compensation can be accomplished without the need for pilot input.

[0052] In another failure scenario, a single winding on a motor can fail. In such a scenario, the opposite motor can be powered down while the motor with the only remaining winding can be powered up. The power supplied by the batteries can be modulated to balance the discharge of the individual batteries. In yet another failure scenario, a battery can fail. In this case, the opposite motor can be reduced by 10-20% where the only remaining battery on the motor provides additional power with the failed battery / inverter and the differential power along the ring is used to spread the battery discharge. In the case of a full battery failure in a ring architecture, this would result in two motors each having a set of windings that are not powered, the remaining set of windings in each of the adjacent motors would draw increased power from the battery of that set of windings, and there would be differentially adjusted power around the ring in order to best equalize the battery discharge rate. The opposite motor would be partially powered down to maintain an appropriate discharge rate.

[0053] Figure 8 A bar graph 235 illustrating four flight modes and the battery discharge rate for each flight mode is shown. The vertical axis in the bar graph is the battery discharge rate C. The battery discharge rate is a normalized coefficient where a 1C discharge rate would discharge the battery in one hour. 2C would discharge the battery in 30 minutes, a 3C discharge rate would discharge the battery in 20 minutes, and so on. The maximum peak discharge rate 236, which in this example embodiment is approximately 5C, can be set by the limits of the battery chemistry. The nominal flight modes are hover 232, transition 233, and cruise 234. The cruise discharge rate 240 can be approximately 1C. As the aircraft approaches landing, the aircraft will change to the transition mode 233, which can have a transition discharge rate 239 of approximately 2C. Then, as the aircraft lands, the aircraft will enter the hover mode 232, which can have a discharge rate of approximately 2.5C. In the case of a motor failure, the aircraft can enter the emergency hover mode 231, where the opposite motor can be powered down for attitude stability. The hover mode discharge rate 237 can exceed 3C.

[0054] In the example embodiment, the maximum gross takeoff weight (MGTOW) can be 4200 pounds. The discharge rate exceeds the out of ground effect (OGE) where the total energy storage of all batteries is 150 kWh. In the case of an emergency landing in the emergency hover mode 231, the expected time using the high discharge rate of the emergency hover discharge rate 237 is approximately 1 minute.

[0055] Figure 9A flight control system architecture for a high-reliability electrically driven aircraft is illustrated in accordance with some embodiments of the present application. In an exemplary embodiment, a flight computer 111 of the control system receives flight commands 114 from a mission computer 112 and a pilot 113. The flight computer can also receive input from a suite of flight critical sensors 110. The flight critical sensors can be triply redundant. The flight computer can be triply redundant. The system can include a voting bridge 116 on each actuator 115. Figure 10 A flight control software architecture is illustrated in accordance with some embodiments of the present application.

[0056] In some embodiments of the present application, other battery and motor architectures can be used, which further enhance the fault tolerance of the system. In some aspects, as Figure 11A As seen in FIG. 12, a dual architecture 120 is used, which uses four batteries for six propulsion assembly electric motors; left wing tip propulsion assembly 121, left wing propulsion assembly 122, right wing propulsion assembly 123, right wing tip propulsion assembly 124, left rear propulsion assembly 125, and right rear propulsion assembly 126. In the dual architecture, each battery provides power to one or more motors on each side of the longitudinal centerline of the aircraft. By linking the battery that is powering the farthest outboard motor to a motor on the other side of the centerline of the aircraft, then a battery failure has its impact more spread out across the aircraft, reducing the amount of attitude shift due to the battery failure. For example, in the case of a motor failure at the first motor 121, there is still a momentary reduction in power to the fourth motor to compensate for the failure. However, compared to the ring architecture disclosed above, the compensation mechanism for power sharing in the dual architecture using the remaining motors will allow for lower inverter loads in the system. In addition, compared to the ring architecture, the compensation mechanism for power sharing in the dual architecture using the remaining motors will allow for lower battery loads in the system.

[0057] Figure 11B A nominal operating condition for the dual architecture 120 is illustrated in FIG. 13, where each of the four batteries 111, 112, 113, 114 provides 35 KW to one winding of three different motors, for a total of 105 kW delivered by each battery, and a total of 70 kW received by each motor, for a total delivered power of 420 kW. Each motor receives power from three batteries.

[0058] Figure 11CA motor failure case is illustrated, in this example case, a motor 121 failure of the left wingtip propulsion assembly. As illustrated, to offset the loss of the left wingtip motor, the motor 124 on the right wingtip has been de-energized and is no longer drawing any power. Each of the batteries now powers two (instead of the previous three) motors, and each motor receives power from two batteries, instead of the previous three. Each of the batteries is able to run at the same power output level, and each of the motor windings and their associated inverters are also able to run at the same power level.

[0059] Figure 11D A battery failure case is illustrated, in this example case, a first battery 111 failure. In this case, each of the remaining batteries provides the same power output level, although different motors run at different power levels in order to balance the thrust produced on each side of the aircraft centerline.

[0060] Figure 12 A six-battery six-motor hexastar architecture is illustrated in accordance with some embodiments of the present application. In Figure 12 The hexastar architecture illustrated in FIG. 17, each of the six batteries powers two motors, just like the ring architecture. And each motor is powered by two batteries. However, the first battery provides power to the first and third motors, the second battery provides power to the second and fourth motors, and so on. The hexastar architecture creates two independent rings, encompassing the first, third, and sixth motors, and the second, fourth, and fifth motors. By linking the battery that powers the farthest outside to a motor on the other side of the centerline of the aircraft, a battery failure then disperses its impact across the entire aircraft, reducing the amount of attitude shift due to the battery failure. For example, in the case of a motor failure at the first motor, there is still a momentary decrease in power to the fourth motor to compensate for the failure. But, compared to the ring architecture, the compensation mechanism for power sharing in the hexastar architecture using the remaining motors will allow for lower inverter loads in the inverter optimization system. Furthermore, compared to the ring architecture, the compensation mechanism for power sharing in the hexastar architecture using the remaining motors will allow for lower battery loads in the battery optimization system. Figures 15A-15C The maximum loads in the inverters, batteries, and motors for the solutions for inverter optimization, battery optimization, and motor optimization for the various motor-battery architectures described herein during a battery failure are illustrated in Figures 15A-15C In FIG. 17, the hexastar architecture is indicated by a symbol, rather than a name as with the other architectures.

[0061] Figure 13 And Figure 14 A six-motor four-battery system is illustrated in accordance with some embodiments of the present application.Figure 13 A star architecture is illustrated using four batteries to power six motors. Each battery is coupled to three motors. Figure 14 A mesh architecture is illustrated with four batteries and six motors.

[0062] Figure 15A 、 Figure 15B and Figure 15C Max loads in inverters, batteries, and motors are illustrated for solutions for inverter optimization, battery optimization, and motor optimization for the various motor-battery architectures described herein during a motor failure, respectively. The six-pointed star architecture is indicated with a symbol, rather than a name as with the other architectures. As illustrated, the six-pointed star architecture gives the best solution when evaluated with respect to all optimizations (inverter-optimized, battery-optimized, and motor-optimized).

[0063] As will become apparent from the foregoing description, various embodiments can be configured from the descriptions given herein, and additional advantages and modifications will readily occur to those skilled in the art. The application in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Embodiments described herein can include physical structures as well as methods of use. Departures can therefore be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

[0064] The present invention also relates to the following aspects:

[0065] 1. An electrically powered vertical take-off and landing aircraft, the aircraft comprising:

[0066] a plurality of propulsion assemblies, each of the propulsion assemblies comprising an electric motor;

[0067] a plurality of batteries, each of the plurality of batteries coupled to two or more of the electric motors;

[0068] wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the winding circuits in a motor is coupled to a different battery.

[0069] 2. The aircraft of aspect 1, further comprising a plurality of inverters, wherein each of the batteries is coupled to each of the electric motors through an inverter.

[0070] 3. The aircraft of aspect 1, further comprising a flight control system adapted to autonomously adjust power delivered by the batteries to the electric motors in the event of a motor failure to maintain a desired aircraft attitude.

[0071] 4. The aircraft of aspect 2, further comprising a flight control system adapted to autonomously adjust power delivered by the batteries to the electric motors to maintain a desired aircraft attitude in the event of a motor failure.

[0072] 5. The aircraft of aspect 1, further comprising a flight control system adapted to autonomously adjust power delivered by the batteries to the electric motors to maintain a desired aircraft attitude in the event of a battery failure.

[0073] 6. The aircraft of aspect 2, further comprising a flight control system adapted to autonomously adjust power delivered by the batteries to the electric motors to maintain a desired aircraft attitude in the event of a battery failure.

[0074] 7. The aircraft of aspect 1, wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the plurality of motor winding circuits in a motor is coupled to a different battery.

[0075] 8. The aircraft of aspect 2, wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the plurality of motor winding circuits in a motor is coupled to a different battery.

[0076] 9. The aircraft of aspect 4, wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the plurality of motor winding circuits in a motor is coupled to a different battery.

[0077] 10. The aircraft of aspect 6, wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the plurality of motor winding circuits in a motor is coupled to a different battery.

[0078] 11. The aircraft of aspect 1, wherein each of the plurality of batteries is coupled to one or more motors on a left side of a longitudinal axis of the aircraft, and wherein each of the plurality of batteries is coupled to one or more motors on a right side of the longitudinal axis of the aircraft.

[0079] 12. The aircraft of aspect 2, wherein each of the plurality of batteries is coupled to one or more motors on a left side of a longitudinal axis of the aircraft, and wherein each of the plurality of batteries is coupled to one or more motors on a right side of the longitudinal axis of the aircraft.

[0080] 13. The aircraft of aspect 7, wherein each of the plurality of batteries is coupled to one or more motors on a left side of a longitudinal axis of the aircraft, and wherein each of the plurality of batteries is coupled to one or more motors on a right side of the longitudinal axis of the aircraft.

[0081] 14. The aircraft of aspect 8, wherein each of the plurality of batteries is coupled to one or more motors on a left side of a longitudinal axis of the aircraft, and wherein each of the plurality of batteries is coupled to one or more motors on a right side of the longitudinal axis of the aircraft.

[0082] 15. A method for mitigating motor failure of a first motor in a power and propulsion system of a vertical takeoff and landing aircraft, the aircraft comprising:

[0083] a plurality of propulsion assemblies, each of the propulsion assemblies comprising an electric motor;

[0084] a plurality of batteries, each of the plurality of batteries coupled to two or more of the electric motors;

[0085] wherein each of the electric motors comprises a plurality of motor winding circuits, and wherein each of the winding circuits in a motor is coupled to a different battery,

[0086] wherein the method comprises the steps of:

[0087] de-energizing a second motor, the second motor on an opposite side of a longitudinal centerline of the aircraft relative to the first motor; and

[0088] increasing power delivered to some or all of the remaining motors in order to maintain necessary thrust.

[0089] 16. The method of aspect 15, wherein each of the plurality of batteries is coupled to one or more motors on a left side of a longitudinal axis of the aircraft, and wherein each of the plurality of batteries is coupled to one or more motors on a right side of the longitudinal axis of the aircraft.

Claims

1. A method for mitigating motor failure of a motor in a power and propulsion system of a vertical takeoff and landing aircraft, the aircraft comprising: a left fixed wing that generates lift when the aircraft moves forward; a left inboard propulsion assembly and a left outboard propulsion assembly on the left fixed wing, each of the left inboard propulsion assembly and the left outboard propulsion assembly including an electric motor and being operable in a horizontal thrust mode and a vertical thrust mode, one of the left inboard propulsion assembly and the left outboard propulsion assembly being forward of a leading edge of the left fixed wing, one of the left inboard propulsion assembly and the left outboard propulsion assembly being aft of a leading edge of the left fixed wing; a right fixed wing that generates lift when the aircraft moves forward; a right inboard propulsion assembly and a right outboard propulsion assembly on the right fixed wing, each of the right inboard propulsion assembly and the right outboard propulsion assembly including an electric motor and being operable in a horizontal thrust mode and a vertical thrust mode, one of the right inboard propulsion assembly and the right outboard propulsion assembly being forward of a leading edge of the right fixed wing, one of the right inboard propulsion assembly and the right outboard propulsion assembly being aft of a leading edge of the right fixed wing; a right rear propulsion assembly aft of the right inboard propulsion assembly and the right outboard propulsion assembly, the right rear propulsion assembly including an electric motor; a left rear propulsion assembly aft of the left inboard propulsion assembly and the left outboard propulsion assembly, the left rear propulsion assembly including an electric motor; a plurality of batteries, each of the plurality of batteries being coupled to two or more of the electric motors of the left inboard propulsion assembly, the left outboard propulsion assembly, the right inboard propulsion assembly, and the right outboard propulsion assembly; wherein each of the electric motors includes a plurality of motor winding circuits, and wherein each of the motor winding circuits in a motor is coupled to a different battery, wherein the method comprises the steps of: operating the left inboard propulsion assembly, the left outboard propulsion assembly, the right inboard propulsion assembly, and the right outboard propulsion assembly in a vertical thrust generating mode; detecting a failure of a particular propulsion assembly; causing a corresponding propulsion assembly to operate at a reduced power, the corresponding propulsion assembly being symmetrically on an opposite side of a longitudinal centerline of the aircraft relative to the particular propulsion assembly; and increasing power delivered to remaining propulsion assemblies on a side of the longitudinal centerline of the aircraft opposite the particular propulsion assembly.

2. The method of claim 1, wherein, the particular propulsion assembly being coupled to a first battery on the same side of the longitudinal centerline of the aircraft as the particular propulsion assembly, and the particular propulsion assembly being coupled to a second battery on the opposite side of the longitudinal centerline of the aircraft from the particular propulsion assembly, the method further comprising: transferring power from the first battery and the second battery from the particular propulsion assembly to some or all of the remaining propulsion assemblies.

3. The method of claim 1, wherein, The respective propulsion assembly is coupled to a first battery on the same side of the longitudinal centerline of the aircraft as the particular propulsion assembly, and the respective propulsion assembly is coupled to a second battery on the same side of the longitudinal centerline of the aircraft as the particular propulsion assembly, the method further comprising: transferring power from the first and second batteries from the respective propulsion assembly to some or all of the remaining propulsion assemblies.

4. The method of claim 1, further comprising: balancing power delivered from the plurality of batteries so that each battery supplies approximately the same power.

5. The method of claim 4, wherein, each battery in a first group of batteries in the plurality of batteries splits its power between two propulsion assemblies, while each battery in a second group of batteries in the plurality of batteries provides its power to a single propulsion assembly.

6. The method of claim 1, wherein, each electric motor includes a plurality of motor winding circuits, and wherein each of the motor winding circuits in each electric motor is coupled to a different battery, and wherein detecting a failure of a particular propulsion assembly includes detecting a failure of a motor winding circuit in the electric motor of the particular propulsion assembly, the method further comprising: increasing power delivered to another one of the motor winding circuits in the electric motor of the particular propulsion assembly.

7. The method of claim 6, wherein, each of the motor winding circuits in each electric motor is coupled to a separate inverter.

8. The method of claim 1, wherein, operating at reduced power includes: operating the respective propulsion assembly in a range of 0-20% of nominal power.

9. The method of claim 1, wherein, detecting a failure of a particular propulsion assembly includes: detecting that the electric motor in the particular propulsion assembly has stopped drawing current.

10. The method of claim 1, wherein, detecting a failure of a particular propulsion assembly includes: detecting a disturbance to an attitude of the aircraft.

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