Power distribution circuit for vehicles with energy regeneration

Abstract

To provide a power distribution circuit for aircraft and an electric aircraft. [Solution] The power distribution circuit for an aircraft comprises a plurality of batteries, a plurality of inverters, each configured to be coupled to each of the plurality of batteries and to generate a plurality of input phases, a plurality of interphase transformers, each receiving one or more of the plurality of input phases and generating a combined single drive phase, and a motor configured to receive the combined single drive phase from each of the plurality of interphase transformers.

Description

Technical Field

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 969,232, filed Feb. 3, 2020, “POWER DISTRIBUTION CIRCUITS FOR VEHICLES WITH ENERGY REGENERATION,” which is hereby incorporated by reference in its entirety for all purposes.

[0002] This application is also related to U.S. Patent Application Ser. No. 17 / 165,565, filed Feb. 2, 2021, “REDUNDANT POWER DISTRIBUTION CIRCUITS INCLUDING DC / DC CONVERTERS,” and U.S. Patent Application Ser. No. 17 / 165,742, filed Feb. 2, 2021, “REDUNDANT POWER DISTRIBUTION CIRCUITS FOR ELECTRIC VEHICLES,” both of which are filed concurrently and by the same applicant, and which are hereby incorporated by reference in their entirety for all purposes.

Background Art

[0003] The described embodiments generally relate to electrical circuits for a plug-in electric vehicle. More particularly, the present embodiments relate to a power distribution circuit that enables regenerative charging of a battery in an electric vehicle.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Currently, there are various electric vehicles that use multiple batteries to store energy for propulsion. There is a need for a new electrical circuit that protects the batteries from fault events while enabling regenerative charging of the batteries.

Means for Solving the Problems

[0005] In some embodiments, the electric vehicle comprises a DC bus and a plurality of batteries, each coupled in parallel to the DC bus. At least one switch is coupled in series between at least one of the plurality of batteries and the DC bus, and a plurality of inverter circuits are each coupled in parallel to the DC bus. A plurality of motors are each coupled to the respective inverter circuits of the plurality of inverter circuits. In various embodiments, the electric vehicle comprises a plurality of switches, each switch being coupled in series between each of the plurality of batteries.

[0006] In some embodiments, the electric vehicle includes a network of circuits connected in series with each of the multiple batteries and arranged to allow current to flow unidirectionally from each of the multiple batteries to the DC bus. In various embodiments, the network of circuits includes at least one diode. In some embodiments, each switch of the multiple switches is arranged to bypass the network of circuits connected in series with each of the multiple batteries. In various embodiments, the electric vehicle further includes a control device configured to detect a faulty battery among the multiple batteries and, in response, open each of the multiple switches to electrically isolate the faulty battery from the DC bus.

[0007] In some embodiments, the electric vehicle further includes a control device configured to detect a regenerative event and, in response, close at least one switch to transfer power from a DC bus to at least one of a plurality of batteries. In various embodiments, each of the plurality of inverter circuits is configured to produce a multiphase AC output used to drive one or more of the plurality of motors. In some embodiments, each of the plurality of inverter circuits is configured to produce a three-phase output. In some embodiments, the three-phase output produced by each of the plurality of inverter circuits operates AC between 0 and 400 volts at a frequency between 0 and 3 kHz. In various embodiments, each of the plurality of motors is coupled to its own propeller.

[0008] In some embodiments, each of the multiple motors is a synchronous AC permanent magnet motor. In various embodiments, the multiple motors include at least 12 motors.

[0009] In some embodiments, the circuit comprises a plurality of batteries and a plurality of inverters, each coupled to a respective battery of the plurality of batteries and configured to generate a plurality of input phases. A plurality of interphase transformers, each receiving one or more of the plurality of input phases, generate a combined single drive phase. A motor is configured to receive a combined single drive phase from each of the plurality of interphase transformers. In various embodiments, at least one of the plurality of interphase transformers receives input phases from each of the plurality of inverters.

[0010] In some embodiments, each phase transformer of a plurality of phase transformers receives input phases from each of a plurality of inverters. In various embodiments, each phase transformer of a plurality of phase transformers electrically isolates each of the plurality of input phases from one another. In some embodiments, the circuit further includes a control device configured to control the operation of at least one of the inverters to control the speed and force of a motor. In various embodiments, the control device is configured to detect a faulty battery among the plurality of batteries and, in response, disable each inverter of the plurality of inverters that is coupled to the faulty battery.

[0011] In some embodiments, one or more of the inverters are configured to charge one or more of the batteries when the motor generates power during a regenerative event. In various embodiments, the motor is a synchronous AC permanent magnet motor. In some embodiments, the motor propels an electric vehicle. In some embodiments, the motor is coupled to a propeller.

[0012] In some embodiments, the electric vehicle comprises a plurality of batteries and a plurality of inverters, each inverter being coupled to one of the plurality of batteries and configured to generate a plurality of phases. The motor is configured to receive each of the plurality of phases from each of the plurality of inverters. In various embodiments, each inverter of the plurality of inverters is configured to generate three phases. In some embodiments, the electric vehicle further comprises a control device configured to detect a faulty battery and, in response, disable each of the plurality of inverters coupled to the faulty battery.

[0013] In some embodiments, the control device is configured to control other inverters among a plurality of inverters in order to continue the motor's operation with a reduced number of phases. In various embodiments, one or more of the plurality of inverters are configured to transmit power to one or more of a plurality of batteries when the motor generates power during a regenerative event. In some embodiments, the motor is coupled to a propeller. In various embodiments, the motor is a synchronous AC permanent magnet motor. In some embodiments, the electric vehicle comprises at least 12 motors.

[0014] In some embodiments, the circuit comprises a plurality of batteries and a plurality of DC-DC converters, each coupled to one of the plurality of batteries. A DC bus is coupled in parallel to each of the plurality of DC-DC converters, and a plurality of inverter circuits are each coupled in parallel to the DC bus. A plurality of motors are each coupled to the inverter circuits of the plurality of inverter circuits. In various embodiments, the circuit further comprises a control device configured to monitor the voltage of the DC bus and the voltage of at least one of the plurality of batteries. In some embodiments, the control device is configured to instruct at least one of the plurality of DC-DC converters to deliver voltage from the DC bus to at least one of the plurality of batteries based on a comparison of the voltage of the DC bus and the voltage of at least one of the batteries.

[0015] In some embodiments, the control device is configured to instruct at least one of a plurality of DC-DC converters to transfer power from the DC bus to at least one of a plurality of batteries in response to at least one of a plurality of motors generating power during a regenerative event. In various embodiments, the control device is configured to detect a failure in at least one of the plurality of batteries and, in response, instruct one or more DC-DC converters coupled to one or more of the failed batteries in the plurality of DC-DC converters to isolate one or more of the failed batteries from the DC bus.

[0016] In some embodiments, each of the multiple DC-DC converters includes a control circuit configured to monitor the voltage of the DC bus and to transfer power from the DC bus to its respective battery when the DC bus voltage exceeds a threshold voltage, the threshold voltage being based on the voltage of at least one of the multiple batteries. In various embodiments, the control circuit is configured to transfer power from the DC bus to at least one of the multiple batteries when at least one of the multiple motors generates power during a regenerative event. In some embodiments, the control circuit is configured to detect a failure in at least one of the multiple batteries and, in response, instruct each of the one or more DC-DC converters coupled to one or more of the failed batteries to isolate the one or more failed batteries from the DC bus. In various embodiments, each of the multiple motors is an AC motor. In some embodiments, the multiple motors propel an electric vehicle. In some embodiments, each of the multiple motors is coupled to its respective propeller.

[0017] In some embodiments, the electric vehicle comprises a plurality of batteries and a plurality of DC-DC converters, each configured to generate DC power that is coupled to each of the plurality of batteries and to a common DC bus. A plurality of inverter circuits are coupled to the common DC bus, and a plurality of electric motors are each coupled to each of the plurality of inverter circuits, and each of the plurality of electric motors propels the vehicle.

[0018] In some embodiments, the electric vehicle further includes a control unit configured to monitor the voltage of a common DC bus and the voltage of each of the multiple batteries. In various embodiments, if the common DC bus voltage exceeds the voltage of at least one of the multiple batteries, the control unit commands at least one of the multiple DC-DC converters to transfer power from the common DC bus to each of the multiple batteries. In some embodiments, in response to detecting a failure in one of the multiple batteries, the control unit commands each of the multiple DC-DC converters coupled to the failed battery to isolate the failed battery from the common DC bus.

[0019] In some embodiments, each DC-DC converter in a plurality of DC-DC converters includes a control circuit configured to monitor the voltage of a common DC bus and to transfer power from the common DC bus to its respective battery when the voltage of the common DC bus exceeds a threshold voltage. In various embodiments, in response to detecting a failure in one of the plurality of batteries, the control circuit instructs each DC-DC converter coupled to the failed battery in the plurality of DC-DC converters to isolate the failed battery from the common DC bus. In some embodiments, each of the plurality of electric motors is an AC motor. In various embodiments, each of the plurality of electric motors is coupled to its respective propeller.

[0020] In some embodiments, the circuit comprises a first battery coupled to a first DC-DC converter and a second battery coupled to a second DC-DC converter. A DC bus is coupled in parallel to the first and second DC-DC converters. A first inverter is coupled to the DC bus, and a second inverter is coupled to the DC bus. A first motor is coupled to the first inverter, and a second motor is coupled to the second inverter. In various embodiments, the first and second inverters are coupled in parallel to the DC bus.

[0021] In some embodiments, the circuit further includes a control device configured to monitor the voltage of the DC bus, the voltage of a first battery, and the voltage of a second battery. In various embodiments, the control device instructs a first DC-DC converter to transfer power from the DC bus to the first battery in response to the DC bus voltage being greater than the voltage of at least one of the first and second batteries. In some embodiments, the control device instructs a first DC-DC converter to isolate the first battery from the DC bus in response to detecting a failure in the first battery. In various embodiments, the control device is configured to instruct a first DC-DC converter to transfer power to the first battery when the first motor generates power during a regenerative event.

[0022] In some embodiments, the control device is configured to instruct the first DC-DC converter to transfer power to the first battery during a regenerative event. In various embodiments, the control device is configured to detect a failure in the first battery and, in response, isolate the first battery from the DC bus. In some embodiments, the first and second motors are AC motors. In various embodiments, the first and second motors propel the electric vehicle. In some embodiments, each of the first and second motors is coupled to its respective propeller.

[0023] The present invention achieves many benefits over conventional techniques. For example, embodiments of the present invention provide the ability to isolate a fault in a power distribution circuit from other components and the ability to maintain power delivery to a propulsion motor during a fault. Embodiments also enable a regenerative event to recharge the battery, and individual battery circuits are insulated to prevent charge shuttling between batteries. The above and other embodiments of the present invention will be described in more detail in connection with the following text and the accompanying figures, along with many of the advantages and features of the present invention.

[0024] To better understand the essence and advantages of the present disclosure, reference should be made to the following description and the accompanying figures. However, it should be understood that each of the figures is provided for illustrative purposes only and is not intended to define the limits of the scope of the present disclosure. Further, in principle, and unless the contrary is apparent from the description, when elements in different figures use the same reference numerals, the elements are generally identical or at least similar in function or purpose.

Brief Description of the Drawings

[0025] [Figure 1] A schematic diagram of a power distribution circuit including a protection diode and a bypass switch according to an embodiment of the present disclosure. [Figure 2] A schematic diagram of a power distribution circuit including a breaker according to an embodiment of the present disclosure. [Figure 3] A schematic diagram of a power distribution circuit including an inverter and an interphase transformer according to an embodiment of the present disclosure. [Figure 4] A schematic diagram of a power distribution circuit including an inverter and a 12-phase motor according to an embodiment of the present disclosure. [Figure 5] A schematic diagram of a power distribution circuit including a DC-DC converter coupled to an inverter via a DC bus according to an embodiment of the present disclosure. [Figure 6] A schematic diagram of a power distribution circuit including a common power shaft driven by a plurality of motors according to an embodiment of the present disclosure. [Figure 7]This is a diagram of an electrically powered aerial vehicle including a power distribution circuit according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0026] The techniques disclosed herein generally relate to electrical circuits for electric vehicles. More specifically, the techniques disclosed herein relate to power distribution circuits for electric vehicles, including energy regeneration capabilities and redundant battery systems. Various inventive embodiments, including methods, processes, systems, devices, etc., are disclosed herein.

[0027] To better understand the features and embodiments of the power distribution circuits for electric vehicles as described herein, further background to this disclosure is provided in the following sections by discussing one specific embodiment of an electric vehicle according to the embodiments of this disclosure. These embodiments are for illustrative purposes only, and other embodiments may be used in electric vehicles such as, but not limited to, automobiles, trains, buses, motorcycles, and scooters.

[0028] Figure 1 shows a simplified schematic diagram of a power distribution circuit 100 for an electric vehicle according to an embodiment of the present disclosure. As shown in Figure 1, the power distribution circuit 100 includes several separate batteries 105a to 105c, each of which may contain multiple cells. In one embodiment, each battery 105a to 105c produces a DC voltage of approximately 600 volts, but in other embodiments, the batteries may produce different voltages. Any number of batteries may be used, and some embodiments include between 3 and 15 batteries.

[0029] Each battery is coupled in parallel to a common DC bus 110, which is coupled to a plurality of inverter circuits 115a-115c. Each inverter circuit 115a-115c is configured to produce a multiphase AC output that can be used to drive individual motors 120a-120c, the motors being, in one embodiment, synchronous AC permanent magnet motors. In some embodiments, each inverter circuit 115a-115c is configured to produce a three-phase output operating AC between 0 and 400 volts at frequencies between 0 and 3 kHz, but those skilled in the art will understand that other numbers of phases, output voltages, output frequencies, and types of electric motors may be used without departing from the present invention.

[0030] As further shown in Figure 1, diodes 125a to 125c are connected in series between each of the batteries 105a to 105c and the DC bus 110. Diodes 125a to 125c are oriented to allow batteries 105a to 105c to supply current to the DC bus 110 and to prevent current from flowing back from the DC bus to the batteries. Such a configuration may be used to protect batteries 105a to 105c in the event of a short-circuit failure, which would cause the other batteries to discharge current to the faulty battery. In a further embodiment, diodes 125a to 125c can prevent charge shutting between batteries 105a to 105c, which would result from each battery having a different charge state. More specifically, in some embodiments, each battery 105a-105c may have different aging and / or charge characteristics such that the diodes 125a-125c prevent batteries with relatively higher charge levels from reverse-charging batteries with relatively lower charge levels. Such charge shutting can result in efficiency losses, heat generation, and overall system instability.

[0031] To enable batteries 105a-105c to receive regenerative power generated by motors 120a-120c, each circuit includes bypass switches 130a-130c that selectively bypass their respective diodes 125a-125c. More specifically, when engaged, each bypass switch 130a-130c allows power to be transferred from the DC bus 110 to batteries 105a-105c, so that the batteries can be recharged with power generated by motors 120a-120c. In some embodiments, the bypass switches 130a-130c may be coupled to a control device 135 that monitors the parameters of batteries 105a-105c and the DC bus 110. The control device 135 may be configured to engage bypass switches 130a to 130c to bypass each of the diodes 125a to 125c when the state of the DC bus 110 indicates that a regenerative charging event is in progress (for example, when the voltage level on the DC bus is higher than the voltage level of at least one of the batteries).

[0032] More specifically, in some embodiments, motors 120a to 120c are configured to act as generators, so that when the motors are rotated by an external mechanical force, the motors generate electricity that flows backward to the DC bus 110 through the inverter circuits 115a to 115c. When this occurs, the voltage on the DC bus 110 can rise above the voltage of batteries 105a to 105c, and the control device 135 can detect this rise and respond by closing one or more bypass switches 130a to 130c to allow current to flow from the DC bus to one or more of the batteries. When the regenerative event ends, the voltage on the DC bus 110 falls below the voltage of batteries 105a to 105c, and the control device 135 responds by opening the bypass switches. In some embodiments, the control device 135 enables regenerative charging of batteries 105a-105c only when the voltage of the DC bus 110 exceeds a threshold voltage, and the threshold voltage may be set based on the maximum voltage of any one of the batteries so that charge shutting does not occur once the bypass switch is closed. In further embodiments, the control device 135 may engage only one bypass switch at a time or a subset of bypass switches to recharge individual batteries, which in some embodiments may be used, for example, to "fill up" any battery having a relatively low charge.

[0033] In further embodiments, one or more bypass switches 130a-130c may be engaged by an external circuit, for example, when an operator is specifically engaged in a regenerative operation, such as when an aircraft is descending or a brake pedal is pressed down. In other embodiments, the control device 130 may have a logic circuit that allows the bypass switches 130a-130c to selectively engage in order to recharge only batteries 105a-105c that have a charge level below a certain threshold, or to charge specific batteries in a predetermined order to extend their lifespan. Those skilled in the art who benefit from the present disclosure will recognize many variations, alterations, and alternative techniques for engaging the bypass switches 130a-130c and the methods thereof.

[0034] In some embodiments, the bypass switches 130a to 130c are electromechanical relay type switches that include metal contacts engaged and disengaged by electromagnets. In other embodiments, the bypass switches 130a to 130c are solid-state and made from silicon, gallium nitride, silicon carbide, or other semiconductor materials.

[0035] In some embodiments, the control device 135 may include fault monitoring and detection circuits such that when a fault is detected during regenerative operation (for example, when a battery fails as a short circuit) and one or more of the bypass switches 130a to 130c are closed, the bypass switches for that particular battery 105a to 105c are opened to prevent other batteries from discharging current to the faulty battery. Those skilled in the art who benefit from the present disclosure will recognize many variations, modifications, and alternatives to the use of bypass switches.

[0036] In some embodiments, the power distribution circuit 100 of Figure 1 may be particularly useful for aircraft requiring multiple separate batteries 105a-105c for redundancy purposes. In such embodiments, the separated inverter and motor circuits, as shown in Figure 1, may provide additional redundancy and improved reliability. For example, separate inverter / motor and battery circuits would provide redundancy in the event of, for example, an electrical short circuit or a failure in the DC supply line from one battery to the DC bus 110. In some embodiments, the location of the bypass switches 130a-130c may be near the batteries 105a-105c (as shown in Figure 1), while in other embodiments, the bypass switches 130a-130c may be located near the inverter circuits 115a-115c.

[0037] Batteries 105a to 105c may be lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, alkaline batteries, or any other type of battery. Motors 120a to 120c may be any type of AC motor, including but not limited to brushed motors, brushless motors, induction motors, or synchronous motors. Inverters 115a to 115c may be any type of analog or solid-state inverter circuit that converts DC power to AC power. For simplicity, various active and passive network components are not shown in the power distribution circuit 100.

[0038] Figure 2 shows a power distribution circuit 200, which is similar to the power distribution circuit 100 shown in Figure 1, but in this embodiment it does not include diodes positioned between each battery and the DC bus. Instead, as shown in Figure 2, breakers 230a to 230c are positioned between each battery 105a to 105c and the DC bus 110. During normal operation, the breakers 230a to 230c are in the closed position, so that DC power can flow from the batteries 105a to 105c to the DC bus 110 and through the inverter circuits 115a to 115c to the motors 120a to 120c. The control device 235 is configured to detect a system fault and, in response, open one or more of the breakers 230a to 230c to prevent further faults, as will be described in more detail below.

[0039] In one embodiment, the control unit 235 is configured to detect a failure in a battery 105a-105c that would fail in a short-circuit condition. The control unit 235 then commands the circuit breakers 230a-230c associated with that particular battery 105a-105c to open, preventing the battery from receiving current from other batteries coupled to the DC bus 110. During such a failure, the control unit 235 is configured to keep the other circuit breakers 230a-230c closed so that current can continue to be supplied to the motors 120a-120c. In a further embodiment, the control unit 235 is configured to open only the necessary circuit breakers 230a-230c and keep all other circuit breakers closed so that power can continue to be supplied to the motors 120a-120c. This mode of operation may be particularly useful for aircraft where continuous and uninterrupted operation of the motors 120a-120c is a critical safety consideration.

[0040] In some embodiments, the circuit breakers 230a-230c may be located near batteries 105a-105c (as shown in Figure 2), while in other embodiments, the circuit breakers 230a-230c may be located near motors 120a-120c. In further embodiments, there may be a set of circuit breakers 230a-230c near each battery 105a-105c and another set of circuit breakers near each motor 120a-120c, and these combinations may be used to isolate faults in the wiring harness extending from the batteries to the motors.

[0041] In some embodiments, the breakers 230a to 230c are electromechanical switches including metal contacts. In other embodiments, the breakers 230a to 230c are solid-state and made from silicon, gallium nitride, silicon carbide, or other semiconductor materials.

[0042] Figure 3 shows a power distribution circuit 300 according to an embodiment of the present disclosure. As shown in Figure 3, each battery 105a to 105d is coupled to a separate inverter 310a to 310d that generates its own three-phase AC output. There are also three separate interphase transformers 315a to 315c, each of which receives one input phase from each inverter 310a to 310d and combines these inputs to form a single drive phase 320a to 320c that is coupled to the motor 330. Within each interphase transformer 315a to 315c, each of the four inputs is electrically isolated from one another so that a failure in one input does not result in a failure in any of the other three inputs. In some embodiments, each interphase transformer 315a to 315c is configured to inductively combine the power delivered by each of its four respective inputs to produce an integrated single drive phase 320a to 320c for the motor 320.

[0043] Therefore, each phase of the motor 320 is driven by its respective interphase transformer 315a-315c, which receives approximately 25 percent of its power from each of the four separate inverter / battery sets. If one of the batteries 105a-105d or inverters 310a-310d fails, each phase of the motor 330 will receive less than approximately 25 percent of its power, but the motor will still operate. In some embodiments, a main control device (not shown in Figure 3) may be used to control each phase of each inverter 310a-310c so that the inputs to the interphase transformers 315a-315c are synchronized. In some embodiments, the motor control device circuit may include only the inverters 310a-310d, while in other embodiments, the motor control device circuit may also include the interphase transformers 315a-315c. Due to electrical isolation between the circuits, charge shutting between batteries 105a-105d is also not a problem.

[0044] During a regenerative event, when the motor 330 is rotated by an external mechanical force, the motor delivers power to each interphase transformer 315a-315c, which then send power back to the batteries 105a-105d through separate inverters 310a-310d. Each battery 105a-105d is isolated from each other, so that if one battery fails, power from the other batteries cannot flow to the failed battery. Essentially, each battery and each AC signal is isolated, so that each operates as an independent system. As will be understood by those skilled in the art who benefit from this disclosure, the number of batteries, the number of inverters, and the number of interphase transformers are not limited to those shown in Figure 3, and other embodiments may have a different number of these devices or configurations. For example, six batteries may be used with interphase transformers, each combining six inputs. Those skilled in the art who benefit from this disclosure will recognize many variations, alterations, and alternative configurations.

[0045] Figure 4 shows a power distribution circuit 400, which is similar to the power distribution circuit 300 shown in Figure 3, but in this embodiment there is no phase transformer and the motor has 12 separate windings. As shown in Figure 4, there are four separate batteries 105a to 105d, each of which has a separate inverter 310a to 310d coupled to it. Each inverter 310a to 310d generates a separate phase, and each phase is directly coupled to the motor 405. Thus, the four three-phase inverters 310a to 310d generate 12 phases, all of which are individually coupled to the motor 405.

[0046] In this embodiment, when one of the batteries 105a-105d fails, three of the 12 phases in the motor 405 do not receive power, and therefore the motor still operates, but only at approximately 75 percent of its power. In some embodiments, the circuit may include a control device configured to use other inverters (e.g., non-failed inverters) from a group of inverters to continue the motor's operation with the reduced number of phases. The control device may also control the inverter coupled to the failed battery to isolate it from the circuit. Furthermore, each set of batteries 105a-105d and inverters 310a-310d are electrically isolated from each other, so that if a battery fails in a short-circuit condition, current from other batteries does not flow to the failed battery. Essentially, each set of batteries 105a-105d and inverters 310a-310d is electrically isolated from its respective other set of batteries and inverters. Due to the isolation, charge shutting between batteries 105a-105d is also not a problem.

[0047] During a regenerative event, rotational energy is applied to the motor 405, which acts as a generator and delivers current to each battery 105a-105d through their respective inverters 310a-310d. In other embodiments, the motor 405 may have any number of phases, and the inverters 310a-31d may generate any number of phase outputs.

[0048] Figure 5 shows a power distribution circuit 500 according to an embodiment of the present disclosure. The power distribution circuit 500 is similar to the power distribution circuits 100 and 200 shown in Figure 1 and Figure 2, which use a DC bus, but the embodiment shown in Figure 5 uses DC / DC converters in series with each battery to supply energy to a common DC bus. As shown in Figure 5, each of the individual batteries 105a to 105 is coupled to separate DC / DC converters 505a to 505d, which convert and adjust the DC energy received from each battery into DC energy coupled to a common DC bus 510. The DC bus 510 is coupled in parallel to a plurality of inverters 515a to 515c, which each generate a three-phase AC signal to drive an individual motor 520a to 520c.

[0049] Each DC / DC converter 505a to 505d is configured to receive power only from its respective battery 105a to 105d and to deliver adjusted power to the DC bus 510 based on the load applied to the DC bus. More specifically, in some embodiments, each DC / DC converter 505a to 505d may be independently tuned, and the voltage of the DC bus 510 can be used to control the amount of power that the DC / DC converter draws from its respective battery 105a to 105d. In other embodiments, the control unit 525 may cycle each DC / DC converter 505a to 505d on and off as needed to control each DC / DC converter 505a to 505d and adjust the power delivered to the DC bus 510. More specifically, each DC / DC converter 505a to 505d may operate in a duty cycle that is on for a certain period and off for a certain period.

[0050] In this embodiment, if batteries 105a to 105d fail, the DC / DC converters 505a to 505d for that battery prevent power from being transmitted from the DC bus 510 to the failed battery (for example, if the battery fails in a short-circuit state). In one example, each DC / DC converter 505a to 505d (or control device 525) can monitor the voltage across each of the batteries 105a to 105d to detect a short circuit or failure within the battery and, in response, interrupt the transmission of power from that battery to the DC bus 510. In a further embodiment, the DC / DC converters 505a to 505d can detect a regenerative event and transmit power from the DC bus 510 to the batteries 105a to 105d for recharging. In some embodiments, each DC / DC converter 505a to 505d can detect a regenerative event by monitoring the voltage potential on the DC bus 510 compared to the voltage available in each of the batteries 105a to 105d. In some embodiments, a threshold voltage may be used to initiate regenerative charging when the voltage on the DC bus 510 exceeds the threshold voltage.

[0051] In some embodiments, the DC / DC converters 505a to 505d can adjust the load distribution among the batteries 105a to 105d to maintain each battery in a similar charge state. In one embodiment, each DC / DC converter 505a to 505d monitors the voltage of each battery 105a to 105d and the voltage on the DC bus 510. If the control device 525 detects that the voltage of battery 105a to 105d is relatively higher than that of the other batteries, the control device can instruct each DC / DC converter 505a to 505d to draw more power from that battery to match its charge state to that of the other batteries. In further embodiments, each DC / DC converter 505a to 505d can receive the same PWM (pulse width modulation) signal from the control device 525, which controls the transfer of power from each battery 105a to 105d to the DC bus 510. In some embodiments, the same PWM signal can "automatically" compensate for the different charge levels in batteries 105a to 105d by delivering more power from batteries with relatively higher charges due to their higher voltage levels and relatively less power from batteries with relatively lower charges due to their lower voltage levels.

[0052] In some embodiments, the DC / DC converters 505a to 505d may be located near the batteries 105a to 105d, while in other embodiments, the DC / DC converters 505a to 505d may be located near the motors 502a to 502c. In further embodiments, the DC bus 510 may be omitted, and each DC / DC converter 505a to 505d may be coupled to its respective inverter 515a to 515c, and each inverter may be coupled to its respective motor 520a to 520c as shown in Figures 3 and 4.

[0053] In some embodiments, the DC / DC converters 505a-505d may be isolated or non-isolated switch-mode converters. In various embodiments, isolated DC / DC converters 505a-505d may be preferable to isolate the downstream network from potential failures of the batteries 105a-105d. In some embodiments, the DC / DC converters 505a-505d may have the following architectures, namely step-down / back, step-up boost, SEPIC, back-boost, or flyback. In further embodiments, the DC / DC converters 505a-505d may use one or more solid-state switches, which may include silicon, silicon carbide, gallium nitride, or any other type of solid-state switch.

[0054] Figure 6 shows a power distribution circuit 600 according to an embodiment of the present disclosure. The power distribution circuit 600 is similar to the power distribution circuits disclosed in Figures 3 and 4, which have one battery coupled to each inverter, but in Figure 6, each inverter operates redundant motors coupled to a single shaft. As shown in Figure 6, three individual motors 605a to 605c are coupled to a single propeller shaft 610. Each of the three motors 605a to 605c is driven by separate batteries 105a to 105c so that if one battery fails, the remaining motors and batteries can be electrically isolated and still supply power to the propeller shaft 610. When the propeller 615 is rotated by an external mechanical force during a regenerative event, each of the individual motors 605a to 605c generates power that is sent back to their respective batteries 105a to 105c. If one battery 105a-105c or inverter 310a-310c fails, the propeller 615 will still be operated by the remaining two motors 605a-605c, but with approximately 33% less power. In other embodiments, fewer than three separate motors may be used per shaft, and in some embodiments, more than three motors may be used per shaft. In further embodiments, each motor 605a may be powered via a redundant power distribution system as shown in Figures 1-3 or Figure 5.

[0055] Figure 7 shows a simplified plan view of an aircraft 700 according to an embodiment of the present disclosure. As shown in Figure 7, the aircraft 700 includes twelve motors 705a to 705l coupled to a battery pack 710 via a harness 715. The aircraft 700 may use one or any combination of the power distribution circuits described above and shown in Figures 1 to 6.

[0056] Although electric vehicle 700 is described and illustrated as one specific electric vehicle, embodiments of the present disclosure are suitable for use with a variety of electric vehicles. 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 cases, embodiments of the present disclosure are particularly well suited for use with aircraft due to the reliability and fault isolation of the power delivery circuit. Although control circuits are not shown for each of the circuits shown in Figures 1-6, one or more control circuits may be added to any of the circuits described herein to control the operation of various components, including but not limited to inverters, phase transformers, switches, motors, and feedback loops.

[0057] For the sake of brevity, various active and passive network components are not shown in the figures. In the above specification, embodiments of the Disclosure have been described with reference to numerous specific details that may vary by embodiment. Therefore, the specification and drawings should be considered in an illustrative rather than restrictive sense. The sole and exclusive indicator of the Disclosure, and what the Applicant intends to be the scope of the Disclosure, is the literal and equivalent scope of such claims, from which a set of claims derived from this application arises, including any subsequent amendments. Specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of the embodiments of the Disclosure.

[0058] Furthermore, spatially relative terms such as “bottom” or “top” may be used to describe the relationship between an element and / or feature and another element and / or feature, for example, as shown in the figure. It will be understood that spatially relative terms are intended to encompass various orientations of the device in use and / or operation, in addition to the orientation depicted in the figure. For example, if the device in the figure is inverted, an element described as the “bottom” surface may be oriented “above” other elements or features. The device may be oriented in other ways (e.g., rotated 90 degrees or into other orientations), and the spatially relative descriptors used herein shall be interpreted accordingly.

[0059] As used herein, the terms “and,” “or,” and “or” may have a variety of meanings, which may also depend at least partially on the context in which such terms are used. Typically, when “or” is used to relate a list such as A, B, or C, it is intended herein to mean A, B, and C in an inclusive sense, and A, B, or C in an exclusive sense. Furthermore, as used herein, the term “one or more” may be used to describe any feature, structure, or characteristic singly, or to describe several combinations of features, structures, or characteristics. However, it should be noted that these are merely illustrative examples, and the subject matter of the claims is not limited to these examples. Furthermore, when the term “at least one of” is used to relate a list such as A, B, or C, it may be interpreted to mean any combination of A, B, and / or C, such as A, B, C, AB, AC, BC, AA, AAB, ABC, AABBCC, etc.

[0060] Throughout this specification, any reference to “one example,” “one example,” “several examples,” or “exemplary embodiments” means that any particular feature, structure, or characteristic described in relation to the features and / or examples may be included in at least one feature and / or example of the claimed subject matter. Therefore, the appearance of phrases such as “in one example,” “one example,” “several examples,” “several embodiments,” or other similar phrases in various places throughout this specification does not necessarily refer to the same features, examples, and / or limitations. Furthermore, any particular feature, structure, or characteristic may be combined in one or more examples and / or features.

Claims

1. A power distribution circuit for an aircraft, Multiple batteries, Multiple inverters, each configured to be coupled to each of the multiple batteries and to generate multiple input phases, A plurality of interphase transformers, each receiving one or more of the plurality of input phases and generating a single combined drive phase, A motor configured to receive the combined single drive phase from each of the plurality of inter-phase transformers, A power distribution circuit equipped with the following features.

2. The power distribution circuit according to claim 1, wherein at least one of the plurality of phase transformers receives input phase from each of the plurality of inverters.

3. The power distribution circuit according to claim 1, wherein each of the phase-to-phase transformers of the plurality of phase-to-phase transformers receives an input phase from each of the plurality of inverters.

4. The power distribution circuit according to claim 1, wherein each of the phase-to-phase transformers of the plurality of phase-to-phase transformers electrically isolates the plurality of input phases from each other.

5. The power distribution circuit according to claim 1, further comprising a control device configured to control the operation of at least one of the inverters for controlling the speed and force of the motor.

6. The power distribution circuit according to claim 5, wherein the control device is configured to detect a faulty battery among the plurality of batteries and, in response, disable each inverter among the plurality of inverters that is coupled to the faulty battery.

7. The power distribution circuit according to claim 1, wherein one or more of the plurality of inverters is configured to charge one or more of the plurality of batteries when the motor generates power during a regenerative event.

8. The power distribution circuit according to claim 1, wherein the motor is a synchronous AC permanent magnet motor.

9. The power distribution circuit according to claim 1, wherein the motor propels the aircraft.

10. The power distribution circuit according to claim 1, wherein the motor is coupled to the propeller of the aircraft.

11. Multiple batteries, A plurality of inverters, each of which is configured to be coupled to each of the plurality of batteries and to generate a plurality of phases, A motor configured to receive each of the multiple phases from each of the multiple inverters, An electric aircraft equipped with [specific features / equipment].

12. The electric aircraft according to claim 11, wherein each inverter of the plurality of inverters is configured to generate three phases.

13. The electric aircraft according to claim 11, further comprising a control device configured to detect a faulty battery and, in response, disable each inverter among the plurality of inverters that is coupled to the faulty battery.

14. The electric aircraft according to claim 13, wherein the control device is configured to control the other inverters among the plurality of inverters in order to continue the operation of the motor with a reduced number of phases.

15. The electric aircraft according to claim 11, wherein one or more of the plurality of inverters is configured to transmit power to one or more of the plurality of batteries when the motor generates power during a regenerative event.

16. The electric aircraft according to claim 11, wherein the motor is coupled to the propeller of the electric aircraft.

17. The electric aircraft according to claim 11, wherein the motor is a synchronous AC permanent magnet motor.

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