Emergency energy storage solutions for battery-electric aircraft

Abstract

A power distribution control technique uses controllably energized and de-energized power distribution buses to control which air vehicle systems receive power based on an applicable operational mode. A method for controlling power distribution in an electric vertical take-off and landing (VTOL) aircraft includes receiving an operational mode instruction identifying an operational mode. The operational mode is one of predetermined operational modes for the aircraft. Power distribution buses in the aircraft are controlled based on the operational mode instruction to control each of the power distribution buses to be energized or de-energized.

Description

[Technical Field]

[0001] This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 439,413, filed January 17, 2023, entitled "Emergency Energy Reserve Solution for Battery Electrified Aircraft," the disclosure of which is incorporated herein by reference in its entirety for all purposes. [Background technology]

[0002]

[0003] Passenger aircraft safety regulations include requirements directed at ensuring the aircraft's ability to continue safe flight and landing for more than extremely unlikely failure conditions. For example, essential flight control systems, such as flight control surface systems (e.g., ailerons, elevators, rudder, etc.), and avionics, may be required to have sufficient redundancy and / or reliability to ensure the aircraft's ability to continue safe flight and landing for some failure conditions.

[0003] Electric vertical take-off and landing passenger aircraft have configurational differences relative to conventional fuel-powered aircraft that are associated with additional considerations to ensure the aircraft's ability to sustainedly fly and land safely. These additional considerations include the reliability and / or redundancy of the power distribution system and the various states of charge of the batteries. Summary of the Invention [Means for solving the problem]

[0004] The following presents a brief summary of some embodiments of the invention in order to provide a background understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key / critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

[0005] A technique and system for controlling power distribution in an air vehicle uses a power distribution bus that is controllably energized and de-energized based on the air vehicle's mode of operation. The ability to selectively energize and / or de-energize the power distribution bus may be used to enhance the safety of the operational mode. For example, one or more power distribution buses that supply power to non-essential subsystems may be de-energized when necessary to ensure that available battery power is dedicated to critical subsystems required for sustained and safe flight and landing. In some embodiments, at least one direct current (DC)-to-DC converter is used to provide power to flight-critical low-voltage subsystems, such as control systems and avionics, by generating a regulated low-voltage output from a high-voltage battery at a low state of charge.

[0006] Accordingly, in one aspect, a method for controlling power distribution in an electric vertical take-off and landing (VTOL) aircraft is provided. The method includes receiving an operational mode instruction identifying an operational mode of the aircraft, the operational mode being one of predetermined operational modes for the aircraft. The method further includes controlling power distribution buses of the aircraft based on the operational mode instruction to control each of the power distribution buses to be energized or de-energized.

[0007] In some embodiments of the method, the power distribution bus includes a propulsion power bus, an air conditioning power bus, and at least one subsystem bus. The propulsion power bus is configured to provide power to propulsion system motors of the aircraft. The air conditioning power bus is configured to provide power to an air conditioning system of the aircraft. The at least one subsystem bus is configured to provide power to a subsystem of the aircraft. In some embodiments of the method, the at least one subsystem bus includes a first subsystem bus and a second subsystem bus. Each of the first subsystem bus and the second subsystem bus can be configured to provide power to a subsystem of the aircraft to provide redundancy.

[0008] In some embodiments of the method, the predetermined operating modes include a normal flight mode and an emergency flight mode. In the normal flight mode, the propulsion power bus, the air conditioning power bus, and each of the at least one subsystem bus are energized. In the emergency flight mode, the air conditioning power bus is de-energized and the propulsion power bus and each of the at least one subsystem bus are energized. In some embodiments of the method, the predetermined operating modes further include an emergency landing mode, in which the at least one subsystem bus is energized and each of the propulsion power bus and the air conditioning power bus are de-energized.

[0009] In another aspect, an air vehicle includes an electric propulsion unit, an air conditioning system, an electric subsystem, a propulsion power bus, an air conditioning power bus, at least one subsystem bus, a control unit, and a memory device. The propulsion power bus is configured to provide power to the propulsion unit. The air conditioning power bus is configured to provide power to the air conditioning system. The at least one subsystem bus is configured to provide power to the subsystems. The control unit includes at least one processor. The memory device stores non-transitory instructions executable by the at least one processor to cause the at least one processor to control each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus to be energized or deenergized based on an indicated operating mode. The indicated operating mode is one of predetermined operating modes for the air vehicle. In some embodiments of the air vehicle, the at least one subsystem bus includes a first subsystem bus and a second subsystem bus. Each of the first subsystem bus and the second subsystem bus can be configured to provide power to a subsystem of the air vehicle to provide redundancy.

[0010] In some embodiments of the air vehicle, the predetermined operating modes include a normal flight mode and an emergency flight mode. In the normal flight mode, the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus are each energized. In the emergency flight mode, the air conditioning power bus is de-energized and the propulsion power bus and the at least one subsystem bus are each energized. In some embodiments of the air vehicle, the predetermined operating modes further include an emergency landing mode, in which the at least one subsystem bus is energized and the propulsion power bus and the air conditioning power bus are each de-energized.

[0011] For a more complete understanding of the nature and advantages of the present invention, reference should be made to the following detailed description and accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 illustrates an electric air vehicle including a power distribution system according to an embodiment. [Figure 2] 2A and 2B are schematic diagrams illustrating aspects of the power distribution system of FIG. 1 including a power distribution bus that can be controllably energized and de-energized; [Figure 3] 3A-3C are diagrams illustrating schematically exemplary aircraft operating modes and corresponding energization states of the power distribution bus of FIG. 2. [Figure 4] 2A and 2B are diagrams illustrating schematically an approach for generating high and low voltage outputs that may be used in the power distribution system of FIG. 1; [Figure 5] 2A and 2B are diagrams illustrating generally techniques for generating high-voltage and regulated low-voltage outputs that may be used in the power distribution system of FIG. 1; [Figure 6] 2 is a plot illustrating an exemplary variation of battery module output voltage with time-of-flight for the power distribution system of FIG. 1. [Figure 7] FIG. 1 is a simplified schematic diagram of a method for controlling power distribution in an electric vertical take-off and landing aircraft, according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the following description, various embodiments of the present invention are described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that the present invention may be practiced without the specific details. Additionally, well-known features may be omitted or simplified so as not to obscure the described embodiments.

[0014] Turning now to the drawings, in which like reference designators are used to indicate like elements in the various views, FIG. 1 illustrates an electric air vehicle 100 including a power distribution system 102, according to an embodiment. As shown in FIG. 1 , air vehicle 100 includes twelve motors 105a-105l. Power distribution system 102 includes a battery 110 and a high-voltage distribution subsystem 115, with the twelve motors 105a-105l coupled to battery 110 via high-voltage distribution subsystem 115. In many embodiments, each of the twelve motors 105a-105l is used to drive a propulsion fan 112 (e.g., a tiltable lift / propulsion fan) and is configured to operate at a relatively high supply voltage (e.g., up to 792V) provided by battery 110.

[0015] In addition to motors 105a-105l, air vehicle 100 includes a low-voltage system also powered by battery 110. The low-voltage system includes 24 motor controllers (MCs) (two for each of the 12 motors to provide redundancy), six tilt actuators (T-act) (one for each tilt mechanism used to tilt the corresponding pair of motors mounted on each pylon), four aileron actuators (A-act), two elevator actuators (E-act), one rudder actuator (R-act), an avionics unit (A-unit), a passenger system line replaceable unit (PAX-LRU), lighting, and various other low-voltage systems. Each of the low-voltage systems is configured to operate on relatively low-voltage power (e.g., nominally 28V).

[0016] 2 schematically illustrates aspects of a power distribution system 102 according to an embodiment. The power distribution system 102 includes a control unit 120, a battery high-voltage output 122, a battery low-voltage output 124, a propulsion power bus 126, a propulsion power bus solenoid relay 128, an air conditioning power bus 130, an air conditioning power bus solenoid relay 132, a first subsystem bus 134, a first subsystem bus solenoid relay 136, a second subsystem bus 138, a second subsystem bus solenoid relay 140, a third subsystem bus 142, and a fourth subsystem bus solenoid relay 144. The propulsion power bus 126 is connected to the propulsion motors 105a-105l and configured to power the propulsion motors 105a-105l. The aircraft vehicle 100 includes an air conditioning system 146 for the cabin of the aircraft vehicle 100. The air conditioning power bus 130 is connected to and configured to provide power to the air conditioning system 146. The air vehicle 100 includes a flight-critical low-voltage subsystem 148, which includes 24 motor controllers (MCs), six tilt actuators (T-acts), four aileron actuators (A-acts), two elevator actuators (E-acts), a rudder actuator (R-act), and an avionics unit (A-unit). The air vehicle 100 includes a non-flight-critical low-voltage subsystem 150, which includes a passenger system line replaceable unit (PAX-LRU), lighting, and various other non-flight-critical low-voltage systems described herein. Each of the first subsystem bus 134 and the second subsystem bus 138 is connected to and configured to provide power to the flight-critical low-voltage subsystem 148.

[0017] Control unit 120 includes one or more processors 142 and memory 144. Memory 144 stores non-transient instructions executable by control unit 120 to cause control unit 120 to control solenoid relays 128, 132, 136, 140, and 144 as described herein. Control unit 120 is connected to and configured to control each of propulsion power bus solenoid relay 128, air conditioning power bus solenoid relay 132, first subsystem bus solenoid relay 136, second subsystem bus solenoid relay 140, and third subsystem bus solenoid relay 144. Propulsion power bus solenoid relay 128 is connected between battery high voltage output 122 and propulsion power bus 126. Propulsion power bus solenoid relay 128 is controllable by control unit 120 to connect propulsion power bus 126 to battery high voltage output 122 to energize propulsion power bus 126 and provide power to propulsion motors 105a-105l. Propulsion power bus solenoid relay 128 is controllable by control unit 120 to disconnect propulsion power bus 126 from battery high voltage output 122 to de-energize propulsion power bus 126 and cut off power to propulsion motors 105a-105l. Air conditioning power bus solenoid relay 132 is controllable by control unit 120 to connect air conditioning power bus 130 to battery high voltage output 122 to energize air conditioning power bus 130 and provide power to air conditioning system 146. Air conditioning power bus solenoid relay 132 is controllable by control unit 120 to disconnect air conditioning power bus 130 from battery high voltage output 122 to de-energize air conditioning power bus 130 and cut off power to air conditioning system 146. First subsystem power bus solenoid relay 136 is controllable by control unit 120 to connect first subsystem power bus 134 to battery low voltage output 124 to energize first subsystem power bus 134 and power flight-critical low voltage subsystem 148.The first subsystem power bus solenoid relay 136 is controllable by the control unit 120 to disconnect the first subsystem power bus 134 from the battery low voltage output 124 to de-energize the first subsystem power bus 134 and thereby interrupt the supply of power to the flight-critical low voltage subsystem 148 via the first subsystem power bus 134. The second subsystem power bus solenoid relay 140 is controllable by the control unit 120 to connect the second subsystem power bus 138 to the battery low voltage output 124 to energize the second subsystem power bus 138 and thereby power the flight-critical low voltage subsystem 148. The second subsystem power bus solenoid relay 140 is controllable by the control unit 120 to disconnect the second subsystem power bus 138 from the battery low voltage output 124 to de-energize the second subsystem power bus 138 and thereby interrupt the supply of power to the flight-critical low voltage subsystem 148 via the second subsystem power bus 138. Third subsystem power bus solenoid relay 144 is controllable by control unit 120 to connect third subsystem power bus 142 to battery low voltage output 124 to energize third subsystem power bus 142 and provide power to non-flight-critical low voltage subsystem 150. Third subsystem power bus solenoid relay 144 is controllable by control unit 120 to disconnect third subsystem power bus 142 from battery low voltage output 124 to de-energize third subsystem power bus 142 and interrupt the supply of power to non-flight-critical low voltage subsystem 150 via second subsystem power bus 138.

[0018] 3 schematically illustrates operational modes 200 for air vehicle 100. Operational modes 200 include a maintenance mode 202, a passenger approach / exit mode 204, a mission mode 206, and an emergency mode 208.

[0019] Maintenance mode 202 is suitable for use during maintenance of air vehicle 100. Maintenance mode 202 includes maintenance lockout mode 210, maintenance auxiliary mode 212, and hot maintenance mode 214. In maintenance lockout mode 210, each of propulsion power bus 126, air conditioning power bus 130, first subsystem power bus 134, second subsystem power bus 138, and third subsystem power bus 142 is de-energized, thereby removing power from propulsion motors 105a-105l, air conditioning system 146, flight-critical low voltage subsystem 148, and non-flight-critical low voltage subsystem 150. In maintenance assist mode 212, propulsion power bus 126 is de-energized and each of air conditioning power bus 130, first subsystem bus 134, second subsystem bus 138, and third subsystem bus 142 is energized, thereby removing power from propulsion motors 105a-105l and providing power to air conditioning system 146, flight-critical low voltage subsystem 148, and non-flight-critical low voltage subsystem 150. In hot maintenance mode 214, propulsion power bus 126, air conditioning power bus 130, first subsystem power bus 134, second subsystem power bus 138, and third subsystem power bus 142 are energized, thereby providing power to propulsion motors 105a-105l, air conditioning system 146, flight-critical low voltage subsystem 148, and non-flight-critical low voltage subsystem 150.

[0020] The passenger approach / exit mode 204 is suitable for use during loading and unloading of the air vehicle 100. The passenger approach / exit mode 204 includes a power off mode 216, a standby mode 218, and a battery charge mode 222. In the power off mode 216, each of the propulsion power bus 126 and the air conditioning power bus 130 is de-energized, thereby removing power from the propulsion motors 105a-105l and the air conditioning system 146. In the power off mode 216, each of the first subsystem bus 134, the second subsystem bus 138, and the third subsystem bus 142 may be energized or de-energized depending on whether power is desired to be provided to the low voltage subsystems 148, 150. In standby mode 218, propulsion power bus 126 is de-energized and air conditioning power bus 130, first subsystem bus 134, second subsystem bus 138, and third subsystem bus 142 are each energized, thereby removing power from propulsion motors 105a-105l and providing power to air conditioning system 146 and low voltage subsystems 148, 150, respectively. In battery charge mode 220, propulsion power bus 126 is de-energized and air conditioning power bus 130 is energized, thereby removing power from propulsion motors 105a-105l and providing power to air conditioning system 146. In the battery charging mode 220, each of the first subsystem bus 134, the second subsystem bus 138, and the third subsystem bus 142 may be energized or de-energized depending on whether power is desired to be supplied to the low voltage subsystems 148, 150.

[0021] Mission mode 206 is suitable for use during normal ground and flight mission segments of air vehicle 100. Mission mode 206 includes armed mode 222 and flight mode 224. In armed mode 222, propulsion power bus 126 is de-energized and air conditioning power bus 130, first subsystem power bus 134, second subsystem power bus 138, and third subsystem bus 142 are each energized, thereby removing power from propulsion motors 105a-105l and providing power to air conditioning system 146 and low voltage subsystems 148, 150, respectively. In flight mode 224, each of propulsion power bus 126, air conditioning power bus 130, first subsystem bus 134, second subsystem bus 138, and third subsystem bus 142 is energized, thereby providing power to propulsion motors 105a-105l, air conditioning system 146, and low voltage subsystems 148, 150.

[0022] Emergency modes 208 are suitable for use during an emergency. Emergency modes 208 include out-of-commission mode 226, security mode 228, emergency flight mode 230, and emergency landing mode 232. In out-of-commission mode 226, each of propulsion power bus 126, air conditioning power bus 130, first subsystem power bus 134, second subsystem power bus 138, and third subsystem power bus 142 is de-energized, thereby removing power from propulsion motors 105a-105l, air conditioning system 146, and low-voltage subsystems 148, 150. In security mode 228, each of propulsion power bus 126 and air conditioning power bus 130 is de-energized, thereby removing power from propulsion motors 105a-105l and air conditioning system 146. In emergency flight mode 230, each of air conditioning power bus 130 and third subsystem power bus 142 is de-energized, and each of propulsion power bus 126, first subsystem power bus 134, and second subsystem power bus 138 is energized, thereby removing power from air conditioning system 146 and non-flight-critical low-voltage system 150, and providing power to each of propulsion motors 105a-105l and flight-critical low-voltage subsystem 148. In emergency landing mode 232, each of propulsion power bus 126, air conditioning power bus 130, and third subsystem power bus 142 is de-energized, and each of first subsystem power bus 134 and second subsystem power bus 138 is energized, thereby removing power from propulsion motors 105a-105l, air conditioning system 146, and non-flight-critical low-voltage subsystem 150, and providing power to flight-critical low-voltage subsystem 148.

[0023] FIG. 4 schematically illustrates an approach for producing the high-voltage output 122 and the emergency low-voltage output 152 from the battery 110. The emergency low-voltage output 152 may be used to provide any appropriate portion of the low-voltage output 124. In the illustrated embodiment, the battery 110 includes four battery cells 154 connected in series to generate the high-voltage output 122. The emergency low-voltage output 152 is generated by one of the battery cells 154. The emergency low-voltage output 152 may be generated by any appropriate combination of battery cells 154 connected in parallel, such as two, three, or all four battery cells 154 connected in parallel. The battery 110 may have any appropriate number of battery cells 154, including, but not limited to, four, five, six, seven, eight, or more battery cells 154. The high-voltage output 122 may be supplied to the propulsion power bus 126 and the air-conditioning power bus 130, as described herein. The emergency low-voltage output 152 may be provided to the first subsystem power bus 134 and the second subsystem power bus 138 as described herein. Figure 5 schematically illustrates a variation of the approach of Figure 4 using a DC-DC voltage converter 156 to regulate the voltage of the emergency low-voltage output 152.

[0024] 6 shows a plot illustrating an example variation of battery cell output voltage with flight time for power distribution system 102. The ability to generate suitable low-voltage output power for use by the low-voltage system when the state of charge of battery 110 is relatively low provides the ability to more fully utilize the power stored in battery 110 to operate the low-voltage system, thereby providing enhanced performance to support sustained and safe flight and landing of the aircraft when the state of charge of battery 110 is low.

[0025] Although described herein in the context of an air vehicle 100, the power distribution system 102 and battery 110 may be used in any suitable electric vehicle, system, or device. For example, any electric vehicle that receives at least a portion of its power from one or more batteries may be used with embodiments of the present disclosure. In some instances, embodiments of the present disclosure are particularly well suited for use with air vehicles due to the reliability and fault isolation provided.

[0026] 7 illustrates a simplified schematic diagram of a method 300 for controlling power distribution in an electric vertical take-off and landing (EVTA) aircraft, according to an embodiment. Method 300 may be practiced by any suitable EVTA aircraft, such as those described herein.

[0027] The method 300 includes receiving an operational mode instruction identifying an operational mode of the aircraft, which may be one of predetermined operational modes for the aircraft, and further includes controlling power distribution buses of the aircraft based on the operational mode instruction to control each of the power distribution buses to be energized or de-energized.

[0028] In some embodiments of method 300, the power distribution bus may include a propulsion power bus, an air conditioning power bus, and at least one subsystem bus. The propulsion power bus may be configured to provide power to propulsion system motors of the aircraft. The air conditioning power bus may be configured to provide power to an air conditioning system of the aircraft. The at least one subsystem bus may be configured to provide power to a subsystem of the aircraft.

[0029] In some embodiments of method 300, the at least one subsystem bus may include a first subsystem bus and a second subsystem bus, each of which may be configured to provide power to a subsystem of the aircraft to provide redundancy.

[0030] In some embodiments of method 300, the predetermined operating modes may include a normal flight mode and an emergency flight mode. In the normal flight mode, the propulsion power bus, the air conditioning power bus, and each of the at least one subsystem bus may be energized. In the emergency flight mode, the air conditioning power bus may be de-energized, and the propulsion power bus and each of the at least one subsystem bus may be energized. The predetermined operating modes may further include an emergency landing mode, in which the at least one subsystem bus is energized and the propulsion power bus and each of the air conditioning power bus are de-energized.

[0031] In some embodiments of method 300, the predetermined operating mode may include at least one of a maintenance lockout mode, a maintenance assist mode, or a hot maintenance mode. In the maintenance lockout mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus may be de-energized. In the maintenance assist mode, the propulsion power bus may be de-energized, and each of the air conditioning power bus and the at least one subsystem bus may be energized. In the hot maintenance mode, the air conditioning power bus and the at least one subsystem bus may be energized, and the propulsion power bus may be selectively energized or de-energized.

[0032] In some embodiments of method 300, the predetermined operating modes may include one or more passenger movement modes for use during passenger ingress and / or egress. The one or more passenger movement modes may include one or more of a power-off mode, a standby mode, or a battery charging mode. In the power-off mode, each of the propulsion power bus and the air conditioning power bus may be de-energized. In the standby mode, the propulsion power bus may be de-energized, and the air conditioning power bus and each of the at least one subsystem bus may be energized. In the battery charging mode, the propulsion power bus may be de-energized, and the air conditioning power bus may be energized.

[0033] In some embodiments of method 300, the predetermined operational modes may include one or more mission modes. The one or more mission modes may include one or more of an armed mode and a normal flight mode. In the armed mode, the propulsion power bus may be de-energized, and the air conditioning power bus and each of the at least one subsystem bus may be energized. In the normal flight mode, the propulsion power bus, the air conditioning power bus, and each of the at least one subsystem bus may be energized.

[0034] In some embodiments of method 300, the aircraft includes a high-voltage battery that supplies high-voltage power to at least one of a propulsion power bus or an air-conditioning power bus. The aircraft may include a low-voltage tap, and the high-voltage battery supplies low-voltage power to at least one subsystem bus via the low-voltage tap. The low-voltage tap may include a direct current (DC)-to-DC converter that regulates the voltage of the low-voltage power supplied to the at least one subsystem bus. The voltage of the low-voltage power may be less than 25 percent of the voltage of the high-voltage power.

[0035] In some embodiments of method 300, the aircraft includes a high-voltage battery that supplies high-voltage power to a propulsion power bus and an air-conditioning power bus. The aircraft may include low-voltage taps, and the high-voltage battery supplies low-voltage power to at least one subsystem bus via the low-voltage taps. Each low-voltage tap may include a direct current (DC)-to-DC converter that regulates the voltage of the low-voltage power supplied to the at least one subsystem bus. The voltage of the low-voltage power may be less than 25 percent of the voltage of the high-voltage power.

[0036] Other variations are within the spirit of the invention. Accordingly, while the invention is susceptible to various modifications and alternative constructions, specific illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that it is not the intention to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the appended claims.

[0037] The use of the terms "a," "an," and "the" and similar referents in connection with describing the present invention (particularly in connection with the claims that follow) should be construed to cover both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted. The term "connected" should be construed as partially or wholly contained within, attached to, or joined to one another, even if there is something intervening. Recitation of ranges of values ​​herein, unless otherwise indicated herein, is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, and each separate value is incorporated herein as if it were separately set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "such as"), are intended merely to better illustrate embodiments of the invention and do not pose a limitation on the scope of the invention unless otherwise asserted. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0038] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors expect that skilled artisans will employ such variations as necessary, and the inventors intend that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Furthermore, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0039] All references cited herein, including publications, patent applications, and patents, are incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and to the same extent as if each reference was set forth in its entirety herein.

Claims

1. 1. A method for controlling power distribution in an electric vertical take-off and landing aircraft, comprising: receiving an operational mode indication identifying an operational mode, the operational mode being one of predetermined operational modes for the aircraft; controlling the power distribution buses of the aircraft based on the operational mode indication to control each of the power distribution buses to be energized or de-energized; A method comprising:

2. the power distribution bus comprises a propulsion power bus, an air conditioning power bus, and at least one subsystem bus; the propulsion power bus is configured to provide power to propulsion system motors of the aircraft; the air conditioning power bus is configured to provide power to an air conditioning system of the aircraft; The method of claim 1 , wherein the at least one subsystem bus is configured to provide power to a subsystem of the aircraft.

3. the at least one subsystem bus comprises a first subsystem bus and a second subsystem bus; 3. The method of claim 2, wherein each of the first subsystem bus and the second subsystem bus is configured to supply power to the subsystems of the aircraft to provide redundancy.

4. the predetermined operational modes include a normal flight mode and an emergency flight mode; in the normal flight mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is energized; 3. The method of claim 2, wherein in the emergency flight mode, the air conditioning power bus is de-energized and the propulsion power bus and each of the at least one subsystem bus are energized.

5. 5. The method of claim 4, wherein the predetermined operational modes further include an emergency landing mode, wherein in the emergency landing mode, the at least one subsystem bus is energized and each of the propulsion power bus and the air conditioning power bus is de-energized.

6. the predetermined operating mode includes at least one of a maintenance lockout mode, a maintenance assist mode, or a hot maintenance mode; in the maintenance lockout mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is de-energized; in the maintenance assist mode, the propulsion power bus is de-energized, and the air conditioning power bus and each of the at least one subsystem bus are energized; 3. The method of claim 2, wherein in the hot maintenance mode, the air conditioning power bus and each of the at least one subsystem bus are energized, and the propulsion power bus may be selectively energized or de-energized.

7. the predetermined operational modes include one or more passenger movement modes for use during passenger ingress and / or egress; the one or more passenger movement modes include one or more of a power off mode, a standby mode, or a battery charging mode; in the power-off mode, each of the propulsion power bus and the air-conditioning power bus is de-energized; in the standby mode, the propulsion power bus is de-energized, and the air conditioning power bus and each of the at least one subsystem bus are energized; The method of claim 2 , wherein in the battery charging mode, the propulsion power bus is de-energized and the air conditioning power bus is energized.

8. the predetermined operational modes include one or more mission modes; the one or more mission modes include one or more of an armed mode and a normal flight mode; in the armed mode, the propulsion power bus is de-energized, and the air conditioning power bus and each of the at least one subsystem bus are energized; The method of claim 2 , wherein in the normal flight mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is energized.

9. the aircraft includes a high-voltage battery that supplies high-voltage power to at least one of the propulsion power bus or the air-conditioning power bus; 3. The method of claim 2, wherein the aircraft comprises a low voltage tap, and the high voltage battery supplies low voltage power to the at least one subsystem bus via the low voltage tap.

10. 10. The method of claim 9, wherein the low voltage tap comprises a direct current (DC) to DC converter that regulates the voltage of the low voltage power supplied to the at least one subsystem bus.

11. The method of claim 10 , wherein the voltage of the low-voltage power is less than 25 percent of the voltage of the high-voltage power.

12. the aircraft includes a high-voltage battery that supplies high-voltage power to the propulsion power bus and the air-conditioning power bus; 3. The method of claim 2, wherein the aircraft comprises a low voltage tap, and the high voltage battery supplies low voltage power to the at least one subsystem bus via the low voltage tap.

13. 13. The method of claim 12, wherein each of the low-voltage taps comprises a direct current (DC) to DC converter that regulates the voltage of the low-voltage power supplied to the at least one subsystem bus.

14. 14. The method of claim 13, wherein the voltage of the low-voltage power is less than 25 percent of the voltage of the high-voltage power.

15. 1. An air vehicle, comprising: an electrically driven propulsion unit; an air conditioning system; an electrically driven subsystem; a propulsion power bus configured to supply power to the propulsion units; and an air conditioning power bus configured to supply power to the air conditioning system; at least one subsystem bus configured to provide power to said subsystem; a control unit comprising at least one processor; a memory device storing non-transitory instructions executable by the at least one processor to cause the at least one processor to control each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus to be energized or de-energized based on an indicated operating mode, the indicated operating mode being one of predetermined operating modes for the air vehicle; and An air vehicle comprising:

16. the at least one subsystem bus comprises a first subsystem bus and a second subsystem bus; 16. The air vehicle of claim 15, wherein each of the first subsystem bus and the second subsystem bus is configured to supply power to the subsystem to provide redundancy.

17. the predetermined operational modes include a normal flight mode and an emergency flight mode; in the normal flight mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is energized; 16. The air vehicle of claim 15, wherein in the emergency flight mode, the air conditioning power bus is de-energized and the propulsion power bus and each of the at least one subsystem bus are energized.

18. 18. The air vehicle of claim 17, wherein the predetermined operating modes further include an emergency landing mode, wherein in the emergency landing mode, the at least one subsystem bus is energized and each of the propulsion power bus and the air conditioning power bus is de-energized.

19. the predetermined operating mode includes at least one of a maintenance lockout mode, a maintenance assist mode, or a hot maintenance mode; in the maintenance lockout mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is de-energized; in the maintenance assist mode, the propulsion power bus is de-energized, and the air conditioning power bus and each of the at least one subsystem bus are energized; 16. The air vehicle of claim 15, wherein in the hot maintenance mode, the air conditioning power bus and each of the at least one subsystem buses are energized, and the propulsion power bus may be selectively energized or de-energized.

20. the predetermined operational modes include one or more passenger movement modes for use during passenger ingress and / or egress; the one or more passenger movement modes include one or more of a power off mode, a standby mode, or a battery charging mode; in the power-off mode, each of the propulsion power bus and the air-conditioning power bus is de-energized; in the standby mode, the propulsion power bus is de-energized, and the air conditioning power bus and each of the at least one subsystem bus are energized; 16. The air vehicle of claim 15, wherein in the battery charging mode, the propulsion power bus is de-energized and the air conditioning power bus is energized.

21. the predetermined operational modes include one or more mission modes; the one or more mission modes include one or more of an armed mode and a normal flight mode; in the armed mode, the propulsion power bus is de-energized, and the air conditioning power bus and the at least one subsystem bus are energized; 16. The air vehicle of claim 15, wherein in the normal flight mode, each of the propulsion power bus, the air conditioning power bus, and the at least one subsystem bus is energized.

22. a high voltage battery supplying high voltage power to at least one of the propulsion power bus or the air conditioning power bus; 16. The air vehicle of claim 15, further comprising: a low voltage tap through which said high voltage battery supplies low voltage power to said at least one subsystem bus.

23. 23. The air vehicle of claim 22, wherein the low voltage tap comprises a direct current (DC) to DC converter that regulates the voltage of the low voltage power supplied to the at least one subsystem bus.

24. 24. The air vehicle of claim 23, wherein the voltage of the low-voltage power is less than 25 percent of the voltage of the high-voltage power.

25. a high voltage battery supplying high voltage power to the propulsion power bus and the air conditioning power bus; a low voltage tap through which the high voltage battery supplies low voltage power to the at least one subsystem bus; 16. The air vehicle of claim 15, comprising:

26. 26. The air vehicle of claim 25, wherein each of the low voltage taps comprises a direct current (DC) to DC converter that regulates the voltage of the low voltage power supplied to the at least one subsystem bus.

27. 27. The air vehicle of claim 26, wherein the voltage of the low-voltage power is less than 25 percent of the voltage of the high-voltage power.

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