AC power system for vehicle

Abstract

An AC electrical system for a vehicle and a method of operation thereof are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first motor to the first AC bus and a second electrical channel electrically couples the second motor to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first electrical channel and the second electrical channel such that power generated by one electric machine can be converted and shared with electrical loads of the other electric machine and the other channel.

Description

[0001] This application is a continuation-in-part of the application for “AC Power System for a Carrier” filed on May 19, 2022, having application number 202210545354.9. TECHNICAL FIELD

[0002] The present subject matter relates generally to an AC electrical system for a carrier, such as an aircraft. BACKGROUND

[0003] Conventional commercial aircraft typically include a fuselage, a pair of wings, and a propulsion system that provides thrust. The propulsion system typically includes at least two aircraft engines, such as turbofan jet engines. Each turbofan jet engine is mounted to a respective one of the aircraft wings, such as in a pylon position under the wing, separate from the wing and the fuselage.

[0004] More recently, hybrid-electrically designed propulsion systems have been proposed. With these propulsion systems, an electrical power source can provide electrical power to an electric fan to power the electric fan and can also provide electrical power to various aircraft loads. An electrical power system that is able to provide such electrical power while maintaining robustness and redundancy in the design would be beneficial. SUMMARY

[0005] Aspects and advantages of the disclosure will be set forth in part in the following description, or can be apparent from the description, or can be learned through practice of the

[0006] In one example embodiment of the present disclosure, an AC electrical system for a carrier is provided. The AC electrical system includes a first electric machine mechanically coupled to a first spool of a gas turbine engine and a second electric machine mechanically coupled to a second spool of the gas turbine engine. The system also includes a first electrical pathway electrically coupling the first electric machine to a first AC bus and electrically coupling the first AC bus to one or more electrical loads. The system further includes a second electrical pathway electrically coupling the second electric machine to a second AC bus and electrically coupling the second AC bus to the one or more electrical loads. The system also includes one or more power converters and one or more connection links to selectively electrically couple the first electrical pathway and the second electrical pathway. In this way, electrical power generated by one electric machine can be converted and shared with the electrical loads of the other electric machine and the other pathway.

[0007] These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0008] A complete and enabling disclosure of the present disclosure, directed to one of ordinary skill in the art, is set forth in the specification in conjunction with the attached drawings, in which:

[0009] Figure 1 is a top view of an aircraft in accordance with various exemplary embodiments of the present disclosure;

[0010] Figure 2 is a schematic cross-sectional view of a gas turbine engine of the aircraft mounted to Figure 1 ;

[0011] Figure 3 is a schematic cross-sectional view of an electric fan assembly in accordance with exemplary embodiments of the present disclosure;

[0012] Figure 4 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with one example embodiment of the present disclosure;

[0013] Figure 5 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with one example embodiment of the present disclosure;

[0014] Figure 6 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with another example embodiment of the present disclosure;

[0015] Figure 7 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with yet another example embodiment of the present disclosure;

[0016] Figure 8 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with a further example embodiment of the present disclosure;

[0017] Figure 9 is a schematic diagram depicting an AC electrical system for a vehicle in accordance with yet another example embodiment of the present disclosure;

[0018] Figure 10 is a schematic diagram of the AC electrical system of Figure 5 , and depicts an example manner in which power can be distributed through the AC electrical system in accordance with one example embodiment of the present disclosure;

[0019] Figure 11 is a schematic diagram of an AC electrical system for a vehicle in accordance with one example embodiment of the present disclosure, and depicts an example manner in which power can be transmitted through the system in response to a detected power generation failure;

[0020] Figure 12is a schematic diagram of an AC electrical system for a vehicle according to further example embodiments of the present disclosure, and depicts an example manner in which power can be transmitted through the system in response to a detected power generation failure;

[0021] Figure 13 is a schematic diagram of an AC electrical system for a vehicle according to further example embodiments of the present disclosure, and depicts an example manner in which power can be transmitted through the system in response to a detected power generation failure;

[0022] Figure 14 is a schematic diagram of an AC electrical system for a vehicle according to further example embodiments of the present disclosure, and depicts an example manner in which power can be transmitted through the system in response to a detected power generation failure;

[0023] Figure 15 is a schematic cross-sectional view of a three-spool gas turbine engine according to one example embodiment of the present disclosure;

[0024] Figure 16 is a flow diagram of a method of transmitting power between spools of a gas turbine engine according to one aspect of the present disclosure;

[0025] Figure 17 is a flow diagram of a method of transmitting power between spools of a gas turbine engine according to one aspect of the present disclosure;

[0026] Figure 18 is a block diagram of an example computing system according to example aspects of the present disclosure; and

[0027] Figures 19 to 22 Various circuit diagrams are provided that describe example manners in which a first AC bus of an AC electrical system of a vehicle can be electrically coupled with a second AC bus. DETAILED DESCRIPTION

[0028] Reference will now be made in detail to the current embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0029] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless otherwise implied by context, the description herein of any example is not necessarily to be construed as an exclusion of that example and other examples from the scope of the present disclosure.

[0030] As used herein, the terms “first,” “second,” and “third” can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0031] The terms "forward" and "aft" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, with respect to a gas turbine engine, forward refers to a position closer to the engine inlet and aft refers to a position closer to the engine nozzle or exhaust.

[0032] The terms "upstream" and "downstream" refer to the relative direction with respect to the flow of fluid in a fluid pathway. For example, "upstream" refers to the direction from which the fluid flows and "downstream" refers to the direction to which the fluid flows.

[0033] Unless otherwise stated herein, the terms "coupled," "fixed," "attached to," and the like, mean directly coupled, fixed, or attached, and also indirectly coupled, fixed, or attached, through one or more intermediary

[0034] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0035] As used herein throughout the specification and claims, approximate language is applied to modify any quantitative representation that can permit variations without resulting in a change of the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about," "approximately," and "substantially,” is not limited to the precise value specified. In at least some instances, the approximate language can correspond to the precision of an instrument used to measure the value, or the precision of a method or machine used to construct or manufacture the component and / or system. For example, the approximate language can refer to within a margin of 1%, 2%, 4%, 10%, 15%, or 20%. These approximate margins can apply to individual values, either end point of a defined numerical range, and / or a range margin between end points.

[0036] Herein and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges included therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0037] The present disclosure relates generally to aircraft AC power systems. In particular, various AC power system architectures are provided that include at least two electric machines coupled to respective spools of a multi-spool gas turbine engine. Electrical power generated by the electric machines is supplied to the engine and to aircraft electrical loads. In some cases, electrical power generated by one electric machine can be directed to the other electric machine or to electrical loads associated with the other electric machine, e.g., for power-assisted operation. In other cases, e.g., in response to a detected power generation failure, electrical power generated by one electric machine can be directed to electrical loads associated with the other electric machine. In such cases, the architectures of the AC power systems provided herein can enable smooth, efficient, and safe transition of power between respective circuits associated with the first and second electric machines.

[0038] In contrast to existing commercial aircraft AC power distribution systems, the architectures of the AC power systems provided herein include at least two electric machines coupled to respective spools of a gas turbine engine, and include either AC / AC converters to allow direct AC / AC bidirectional power transfer between circuits associated with the first and second electric machines, or AC / DC converters (e.g., active rectifiers) to allow DC-level power transfer between the circuits or channels, and subsequent conversion of the DC-level power to AC-level power before being provided to power-assisted electric machines and / or AC electrical loads associated therewith.

[0039] Advantageously, the AC power system architectures provided herein require relatively minimal modification to existing aircraft AC power distribution systems, which is particularly useful for upgrading or overhauling conventional AC systems. Moreover, the AC power system architectures provided herein provide for fault-tolerant dual-channel independent operation and control of the two electric machines of the AC system. The AC power system architectures provided herein can have other benefits and advantages in addition to those explicitly noted herein.

[0040] Reference is now made to the drawings, wherein like numerals refer to like elements throughout, Figure 1 A top view of an exemplary aircraft 10 that can incorporate various embodiments of the present disclosure is provided. As Figure 1As shown, the aircraft 10 defines a longitudinal centerline 14 and a lateral direction L extending therethrough. The aircraft 10 extends between a forward end 16 and an aft end 18, for example in a longitudinal direction parallel to the longitudinal centerline 14. Further, the aircraft 10 includes a fuselage 12 extending longitudinally from the forward end 16 to the aft end 18 of the aircraft 10. The fuselage 12 has a port side and a starboard side. The aircraft 10 also includes a wing assembly. More specifically, the wing assembly includes a first, port wing 20 and a second, starboard wing 22. The first wing 20 and the second wing 22 each extend laterally outward relative to the longitudinal centerline 14 in the lateral direction L. The first wing 20 and a portion of the fuselage 12 together define a first side 24 of the aircraft 10. The second wing 22 and another portion of the fuselage 12 together define a second side 26 of the aircraft 10. For the depicted embodiment, the first side 24 of the aircraft 10 is configured as the port side of the aircraft 10, while the second side 26 of the aircraft 10 is configured as the starboard side of the aircraft 10.

[0041] Each of the wings 20, 22 includes one or more leading edge flaps 28 and one or more trailing edge flaps 30. The aircraft 10 also includes a vertical stabilizer 32 having rudder flaps for yaw control, and a pair of horizontal stabilizers 34 each having elevator flaps 36 for pitch control. The fuselage 12 additionally includes an outer surface or skin 38. It will be appreciated that, Figure 1 The aircraft 10 is exemplary and the inventive aspects of the present disclosure are applicable to aircraft having other suitable configurations. For example, in other embodiments, the aircraft 10 can include stabilizers of any other configuration.

[0042] In addition to Figure 1 Reference is now made to Figure 2 and Figure 3 , Figure 1 The exemplary aircraft 10 additionally includes a propulsion system 50 having a first propulsor assembly 52 and a second propulsor assembly 54. Figure 2 A schematic cross-sectional view of the first propulsor assembly 52 is provided. Figure 3 A schematic cross-sectional view of the second propulsor assembly 54 is provided. As shown, the first propulsor assembly 52 and the second propulsor assembly 54 are each configured as an underwing mounted propulsor assembly.

[0043] With particular reference to Figure 1 and 2 The first propulsor assembly 52 is mounted to, or configured to be mounted to, the first side 24 of the aircraft 10, or more specifically, to the first wing 20 of the aircraft 10. The first propulsor assembly 52 generally includes a core turbine engine 104 (also referred to as a turbomachine) and a primary fan (see Figure 2referred to as "fan 102"). More specifically, for the depicted embodiment, the first propulsor assembly 52 is configured as a turbofan engine 100 (the turbine 104 and fan 102 are configured as part of the turbofan engine 100).

[0044] As shown, the turbofan engine 100 defines an axial direction Al (extending parallel to a longitudinal centerline 101 provided for reference), a radial direction Rl, and a circumferential direction C (extending about the axial direction Al; Figure 2 (not shown in FIG. 1). Generally, as indicated, the turbofan engine 100 includes a fan section 102 and a core turbine engine 104 disposed downstream from the fan section 102. Figure 2

[0045] The core turbine engine 104 includes a substantially tubular engine case 106 that defines an annular core inlet 108. The engine case 106 surrounds, in serial flow relationship: a compressor section including a booster or low pressure (LP) compressor 110 and a high pressure (HP) compressor 112; a combustion section 114; a turbine section including a high pressure (HP) turbine 116 and a low pressure (LP) turbine 118; and a jet exhaust nozzle section 120. The compressor section, combustion section 114, and turbine section together define a core air flowpath 121 that extends from the annular core inlet 108, through the LP compressor 110, HP compressor 112, combustion section 114, HP turbine section 116, LP turbine section 118, and jet exhaust nozzle section 120. A high pressure (HP) shaft 122 drivingly connects the HP turbine 116 to the HP compressor 112. The HP shaft 122, together with rotating components of the HP compressor 112 and HP turbine 116 that are mechanically coupled with the HP shaft 122, collectively form a high pressure spool 160. A low pressure (LP) shaft 124 drivingly connects the LP turbine 118 to the LP compressor 110. The LP shaft 124, together with rotating components of the LP compressor 110 and LP turbine 118 that are mechanically coupled with the LP shaft 124, collectively form a low pressure spool 180.

[0046] The fan section 102 can include a fixed or variable pitch fan 126 having a plurality of fan blades 128 coupled to a disk 130 in a spaced apart manner. As shown, the fan blades 128 extend outwardly from the disk 130 generally along the radial direction Rl. For the depicted embodiment, the fan 126 is configured as a bypass fan 126 having a bypass ratio of about 5.5: 1. The fan blades 128 are coupled to the disk 130 by a plurality of dovetail joints 132. The dovetail joints 132 are configured to allow the fan blades 128 to be selectively pitched relative to the disk 130. The fan 126 is drivingly coupled to the LP shaft 124 by a plurality of fan blades 128. Figure 2 ​Variable pitch fan 126, which is mechanically coupled to a suitable actuation member 132 by way of fan blades 128, each of which is rotatable relative to disc 130 about a pitch axis PI, the actuation member 132 being configured to collectively and uniformly change the pitch of fan blades 128. Fan blades 128, disc 130, and actuation member 132 are rotatable together about longitudinal axis 14 by way of LP spool 180. As noted above, in some embodiments, fan blades 128 can be fixed and incapable of rotation about their respective pitch axes.

[0047] Still referring to Figure 2 , disc 130 is covered by a spinner or rotatable front hub 136 that is aerodynamically shaped to facilitate airflow through the plurality of fan blades 128. Additionally, fan section 102 includes an annular fan case or outer nacelle 138 that circumferentially surrounds fan 126 and / or at least a portion of core turbine engine 104. Nacelle 138 is supported relative to core turbine engine 104 by a plurality of circumferentially spaced apart outlet guide vanes 140. A downstream section 142 of nacelle 138 extends over an outer portion of core turbine engine 104 so as to define a bypass airflow passage 144 therebetween.

[0048] It should also be appreciated that Figure 2 the exemplary turbofan engine 100 depicted in FIG. 1 is provided by way of example only, and that in other exemplary embodiments, turbofan engine 100 can have any other suitable configuration. For example, in other exemplary embodiments, turbofan engine 100 can be configured as a turboprop engine, a turbojet engine, a turbofan engine of different configuration, a non- ducted turbofan engine (e.g., without nacelle 138, but including stationary outlet guide vanes 140), or any other suitable gas turbine engine. For example, the gas turbine engine can be a geared gas turbine engine (e.g., having a reduction gearbox between LP spool 124 and fan 126), can have any other suitable number or configuration of shafts / spools (e.g., can include an intermediate speed shaft / turbine / compressor), etc.

[0049] Furthermore, as Figure 2 shown, exemplary turbofan engine 100 includes a plurality of electric machines, including a first electric machine 170 and a second electric machine 190. For this embodiment, first electric machine 170 is mechanically coupled with HP spool 160, and second electric machine 190 is mechanically coupled with LP spool 180. In this manner, first electric machine 170 is an HP electric machine, and second electric machine 190 is an LP electric machine.

[0050] In at least certain example aspects, the first electric machine 170 can be directly mechanically coupled to the HP spool 160 to operably couple the first electric machine 170 with the HP spool 160. Similarly, in at least certain example aspects, the second electric machine 190 can be directly mechanically coupled to the LP spool 180 to operably couple the second electric machine 190 with the LP spool 180. Alternatively, however, in one or more example aspects, the first electric machine 170, the second electric machine 190, or both, can be indirectly coupled to the HP spool 160 or the LP spool 180, respectively, through a speed change mechanism (e.g., a gear box, a transmission, etc.) to allow for a desired ratio of electric machine speed to spool speed.

[0051] In particular, as shown, the second electric machine 190 is coaxially mounted to and rotatable with the LP shaft 124 of the LP spool 180. As used herein, "coaxially" means that the axes are aligned. Moreover, for the illustrated embodiment, the second electric machine 190 is positioned inboard of the core air flowpath 121 within or aft of the turbine section of the turbofan engine 100, and thus, the second electric machine 190 can be referred to as an embedded electric machine. Similarly, the first electric machine 170 is coaxially mounted to and rotatable with the HP shaft 122 of the HP spool 160. The first electric machine 170 is also positioned inboard of the core air flowpath 121 but within the compressor section of the turbofan engine 100, and thus, the first electric machine 170 can also be referred to as an embedded electric machine. Figure 2

[0052] The first electric machine 170 includes a rotor 172 and a stator 174. The rotor 172 of the first electric machine 170 is rotatable with the HP shaft 122. The stator 174 includes current-carrying elements, such as windings or coils. In this manner, electrical power can be transmitted to the current-carrying elements, and as will be appreciated, electrical energy can be converted to mechanical energy in motoring mode or vice versa in generating mode when the rotor 172 rotates relative to the stator 174. The rotor 172 has rotor components for producing a rotor magnetic field for coupling to a stator magnetic field to effect energy conversion. The rotor components of the rotor 172 can be, but are not limited to, rotor magnets in the case of a permanent magnet synchronous electric machine, a squirrel cage in the case of an induction electric machine, or field windings in the case of a field synchronous electric machine.

[0053] Likewise, the second electric machine 190 includes a rotor 192 and a stator 194. The rotor 192 of the second electric machine 190 is rotatable with the LP shaft 124. The rotor 192 and the stator 194 can be constructed in any of the example manners described above with respect to the first electric machine 170.

[0054] ​In some alternative embodiments, the axis of the second motor 190 and / or the first motor 170 can be radially offset from the axis of the LP shaft 124 and the HP shaft 122, respectively. Further, in some embodiments, the second motor 190 and / or the first motor 170 can be tilted with respect to the axis of the LP shaft 124 and the HP shaft 122, respectively. Further, in one or more exemplary embodiments, the second motor 190 and / or the first motor 170 can be located outside of the core air flow path 121, for example, within the engine case 106 or the nacelle 138 of the turbofan engine 100.

[0055] Further, for this embodiment, both the second motor 190 and the first motor 170 can operate as electric motors in motoring mode and as electric generators in generating mode. However, in alternative embodiments, one or both of the second motor 190 and the first motor 170 can be configured to operate as only electric motors or as only electric generators.

[0056] Still referring to Figure 1 and Figure 2 , the propulsion system 50 includes a power distribution system 58 to allow the first and second motors 170, 190 to be electrically coupled to each other, to other electrically driven components of the turbofan engine 100, and to other components of the propulsion system 50 and / or the aircraft 10. For the depicted embodiment, the power distribution system 58 includes one or more electrical cables or wires 60 along which electrical power can be directed.

[0057] Further, the propulsion system 50 also includes one or more energy storage devices 55 (e.g., one or more batteries or other electrical energy storage devices) electrically connected to the power distribution system 58 for providing electrical power to and / or receiving electrical power from, for example, the second propulsor assembly 54. The inclusion of one or more energy storage devices 55 can provide performance gains and can increase the propulsion capability of the propulsion system 50 during, for example, transient operations. More specifically, the propulsion system 50 including one or more energy storage devices 55 can be able to respond more quickly to speed change demands.

[0058] Now referring specifically to Figure 1 and 3 , the exemplary propulsion system 50 additionally includes a second propulsor assembly 54 positioned or configured to be positioned at a location spaced apart from the first propulsor assembly 52. As shown, the second propulsor assembly 54 is mounted to the second side 26 of the aircraft 10, or more specifically, to the second wing 22 of the aircraft 10. As Figure 3As best shown, the second propulsor assembly 54 is generally configured as an electric propulsion assembly that includes an electric motor and a propulsor. More particularly, for the depicted embodiment, the electric propulsion assembly 200 includes an electric motor 206 and a propulsor / fan 204. The electric propulsion assembly 200 defines an axial direction A2 and a radial direction R2 that extend along a longitudinal centerline axis 202 that extends therethrough for reference. The fan 204 is rotatable about the centerline axis 202 by the electric motor 206.

[0059] The fan 204 includes a plurality of fan blades 208 and a fan shaft 210. The plurality of fan blades 208 are attached to / rotatable with the fan shaft 210 and are generally spaced apart along a circumferential direction of the fan. In certain example embodiments, the plurality of fan blades 208 can be attached to the fan shaft 210 in a fixed manner, or alternatively, such as in the depicted embodiment, the plurality of fan blades 208 can be rotatable about respective pitch axes. For example, the plurality of fan blades 208 each define a respective pitch axis P2 and are attached to the fan shaft 210 such that the pitch of each of the plurality of fan blades 208 can be changed, such as uniformly, by a pitch changing mechanism 211. Changing the pitch of the plurality of fan blades 208 can increase the efficiency of the second propulsor assembly 54 and / or can allow the second propulsor assembly 54 to achieve a desired thrust profile. For such example embodiments, the fan 204 can be referred to as a variable pitch fan.

[0060] Further, for the depicted embodiment, the electric propulsion assembly 200 includes a fan housing or outer nacelle 212 that is attached to the core 214 of the fan 204 by one or more struts or outlet guide vanes 216. The outer nacelle 212 substantially completely surrounds the fan 204, particularly the plurality of fan blades 208. Thus, for the depicted embodiment, the fan 204 can be referred to as a ducted electric fan.

[0061] Still referring to the depicted embodiment in particular, Figure 3 The fan shaft 210 is mechanically coupled to the electric motor 206 within the core 214 such that the electric motor 206 drives the fan 204 through the fan shaft 210. The fan shaft 210 is supported by one or more bearings 218, such as one or more roller bearings, ball bearings, or any other suitable bearings. Additionally, the electric motor 206 can be an inrunner electric motor (i.e., including a rotor positioned radially inward of a stator), or can be an outrunner electric motor (i.e., including a stator positioned radially inward of a rotor).

[0062] The power source, such as the electric machines 170, 190 of the first propulsor assembly 52 and / or the one or more energy storage devices 55, can be electrically connected with the electric motor 206 to provide power thereto. More specifically, the electric motor 206 of the electric propulsion assembly 200 is electrically coupled with the power system by the power distribution system 58, and more specifically, by one or more electrical cables or wires 60 extending therebetween.

[0063] In view of the first propulsor assembly being configured as a gas turbine engine and the second propulsor assembly being configured as an electrically driven fan, the propulsion system according to one or more of the above-described embodiments can be referred to as a gas-electric or hybrid-electric propulsion system. However, it should be appreciated that in other example embodiments, the example propulsion system can have any other suitable configuration, and further, can be integrated into the aircraft 10 in any other suitable manner. For example, in other example embodiments, the hybrid-electric propulsion system can have any suitable number of gas turbine engines (e.g., one, two, three, four, etc.) distributed in any suitable manner (e.g., along the port wing, starboard wing, fuselage, aft position, etc. of the aircraft) and mounted in any suitable manner (e.g., underwing, overwing, integrated into the wing, mounted to the fuselage of the aircraft, mounted to the stabilizer of the engine, mounted at the aft end as a boundary layer ingestion engine, etc.). Similarly, the hybrid-electric propulsion system can have any suitable number of electrically driven fans distributed in any suitable manner (e.g., along the port wing, starboard wing, fuselage, aft position, etc. of the aircraft) and mounted in any suitable manner (e.g., underwing, overwing, integrated into the wing, mounted to the fuselage of the aircraft, mounted to the stabilizer of the engine, mounted at the aft end as a boundary layer ingestion engine, etc.). In instances where multiple gas turbine engines are provided with electric machines to generate electricity, each gas turbine engine can be directed to a single electrically driven fan or group of electrically driven fans, or each gas turbine engine can be in electrical communication with a common electrical bus to provide power to the electrically driven fans.

[0064] Further, it should be appreciated that although the propulsion system described herein is depicted as having been incorporated into the aircraft 10, in other example embodiments, the propulsion system can additionally or alternatively be incorporated into any other suitable vehicle. For example, in other example embodiments, the propulsion system can be incorporated into a nautical vehicle (e.g., a ship or submarine) that uses one or more turbine engines, a locomotive vehicle that uses one or more turbine engines, etc.

[0065] Figure 4 is a schematic diagram depicting an AC electrical system 300 for a vehicle according to one example embodiment of the present disclosure. For example, the AC electrical system 300 can be incorporated into the aircraft 10 of FIG. 1, the nautical vehicle 400 of FIG. 4, the locomotive vehicle 500 of FIG. 5, etc. Figure 1The AC electrical system 300 can form at least a portion of the power distribution system 58 of the aircraft 10. In particular, the AC electrical system 300 can form at least a portion of the power distribution system 58 of the aircraft 10. The AC electrical system 300 can also be incorporated into other suitable vehicles. The AC electrical system 300 is an “AC electrical system” because power is distributed at an “AC level” or as alternating current.

[0066] As will be described further below, the AC electrical system 300 is capable of transferring power between the first electrical pathway and the second electrical pathway of the AC electrical system 300. For example, this can enable power transfer between spools of a gas turbine engine. That is, power generated by a first electric machine coupled with a first spool can be transferred to a second electric machine coupled with a second spool. The second electric machine can then convert the electrical energy into mechanical energy to drive or push the second spool. In this manner, the AC electrical system 300 enables power sharing between spools of a gas turbine engine. Moreover, power generated by one electric machine can be fed to supplement or provide full power for various loads associated with another electric machine (e.g., local loads on the gas turbine engine and / or other vehicle loads).

[0067] As Figure 4 As schematically depicted in FIG. 3, the AC electrical system 300 includes a first electric machine 310 mechanically coupled with a first spool 304 of the gas turbine engine 302. The AC electrical system 300 also includes a second electric machine 340 mechanically coupled with a second spool 306 of the gas turbine engine 302. For this embodiment, the first spool 304 is a high pressure spool of the gas turbine engine 302, and the second spool 306 is a low pressure spool of the gas turbine engine 302. However, in other example embodiments, the first spool 304 can be a low pressure spool, and the second spool 306 can be a high pressure spool. In other example embodiments, particularly in embodiments where the gas turbine engine 302 is a three spool engine having a low pressure spool, a mid pressure spool, and a high pressure spool, the first spool is the mid pressure spool of the gas turbine engine, and the second spool is one of the low pressure spool and the high pressure spool of the gas turbine engine. In other embodiments, the first spool is one of the low pressure spool and the high pressure spool of the gas turbine engine, and the second spool is the mid pressure spool of the gas turbine engine.

[0068] The AC electrical system 300 includes a first electrical pathway 312. The first electrical pathway 312 electrically couples various components associated with the first electric machine 310. For example, as schematically depicted in FIG. 3, the first electrical pathway 312 electrically couples the first electric machine 310 with a first generator 314, a first motor 316, a first power converter 318, and a first power bus 320. The first power bus 320 is electrically coupled with the first electric machine 310 and the first power converter 318. Figure 4As shown, a first electrical channel 312 electrically couples the first electric machine 310 to a first AC bus 314. One or more electrical loads 316A, 316B, 316C may be electrically coupled to the first AC bus 314, for example, via respective load lines 318A, 318B, 318C of the first electrical channel 312. The one or more electrical loads 316A, 316B, 316C may include, but are not limited to, electrically driven pumps, computing components, motors, cabin lights, air conditioning systems, cabin air pressurization systems, and Figure 3 The electric propulsion assembly 200 is associated with the motor 206, etc. Although Figure 4 Three electrical loads are depicted as being associated with the first electrical channel 312, but it should be understood that more or less than three electrical loads are possible.

[0069] The AC electrical system 300 also includes a second electrical channel 342. The second electrical channel 342 electrically couples various components associated with the second motor 340. For example, Figure 4 As shown, a second electrical channel 342 electrically couples the second motor 340 to a second AC bus 344. The second AC bus 344 can be at a different voltage and a different frequency than the first AC bus 314. One or more electrical loads 346A, 346B, 346C can be electrically coupled to the second AC bus 344, for example, via respective load lines 348A, 348B, 348C of the second electrical channel 342. The one or more electrical loads 346A, 346B, 346C can include, but are not limited to, electrically driven pumps, computing components, motors, cabin lights, air conditioning systems, cabin air pressurization systems, and Figure 3 The electric propulsion assembly 200 is associated with the motor 206, etc. Although Figure 4 Three electrical loads are depicted as being associated with the second electrical channel 342, but it should be understood that more or less than three electrical loads are possible.

[0070] like Figure 4 As further shown, AC electrical system 300 includes one or more connection links that selectively electrically couple first electrical channel 312 and second electrical channel 342. AC electrical system 300 also includes a power conversion system having one or more power converters operable to convert power transmitted between first electrical channel 312 and second electrical channel 342 via the one or more connection links so that power generated by second electric machine 340 can be transmitted to first electrical channel 312 and, in some embodiments, so that power generated by first electric machine 310 can be transmitted to second electrical channel 342.

[0071] For example, for Figure 4In the illustrated embodiment, one or more connection links of the AC electrical system 300 include a connection link 280. The connection link 280 electrically couples a first AC bus 314 of a first electrical channel 312 and a second AC bus 344 of a second electrical channel 342. The connection link 280 includes a first bus tie contactor 282 and a second bus tie contactor 284. The first bus tie contactor 282 and the second bus tie contactor 284 can be controlled to selectively allow power to pass therethrough. In this regard, the connection link 280 selectively electrically couples the first electrical channel 312 and the second electrical channel 342.

[0072] For this embodiment, the one or more connection links of the AC electrical system 300 also include an AC bus link 410 that can be controlled to selectively electrically couple or connect a first AC bus 314 associated with the first electrical channel 312 and a second AC bus 344 associated with the second electrical channel 342. One or more bus tie contactors 412 of the AC bus link 410 can be controlled to selectively connect the first electrical channel 312 and the second electrical channel 342 at an AC level. Such bus tie contactors 412 can be controlled to connect the first AC bus 314 and the second AC bus 344, for example, in response to a detected power generation fault associated with one of the motors.

[0073] As described above, the AC electrical system 300 includes a power conversion system 290 having one or more power converters. Figure 4 In the illustrated embodiment, the one or more power converters of power conversion system 290 include a power converter 292 positioned along connecting link 280. More specifically, power converter 292 is positioned along connecting link 280 between first bus tie contactor 282 and second bus tie contactor 284. Generally, power converter 292 is operable to convert power transmitted between first electrical channel 312 and second electrical channel 342 via connecting link 280, so that power generated by one motor can be transmitted to the electrical channel associated with another motor. Specifically, power converter 292 can be controlled to convert the AC voltage and frequency of the power transmitted via connecting link 280 to the AC voltage and frequency of the electrical channel to which the power is transmitted. In some embodiments, as will be provided below, AC electrical system 300 may include multiple power converters to convert power transmitted between first electrical channel 312 and second electrical channel 342. In other embodiments, AC electrical system 300 may include a single power converter to convert power transmitted between first electrical channel 312 and second electrical channel 342.

[0074] like Figure 4Further shown, the AC electrical system 300 includes an energy management system 450 (EMS) for power distribution management. The EMS 450 can include one or more memory devices and one or more processors 452 operable to perform one or more operations, such as controlling various components of the AC electrical system 300 to control the flow of electrical current, and thus, the power through the AC electrical system 300. For example, based at least in part on the power sharing allocation determined for the power assist operation, the one or more processors 452 can control various bus tie contactors of the AC electrical system 300 (e.g., bus tie contactors of the system, one or more power converters, etc.) to direct power from one electrical passageway to another. The EMS 450 can also include other components, such as those set forth in the computing system 800 depicted in Figure 18 FIG. 8. The EMS 450 can be communicatively coupled with the bus tie contactors and / or other components in any suitable manner, such as through one or more wired or wireless communication links. Although not labeled in Figure 4 FIG. 8, various bus tie contactors (e.g., bus ties) are positioned along various passageways of the AC electrical system 300. It should also be appreciated that such devices can be controlled to allow or “interrupt” the flow of electrical current along their respective passageways. The EMS 450 can be communicatively coupled with such bus tie contactors to precisely control the flow of electrical current through the system 300.

[0075] An example manner in which the AC electrical system 300 can facilitate power sharing or power assist between passageways will now be described. Referring to Figure 4 , the one or more processors 452 can initiate a power assist operation. The power assist operation can be initiated based at least in part on data 454 received by the one or more processors 452. The data 454 can be indicative of, for example, a required thrust output of the gas turbine engine 302. The required thrust output can be received in response to, for example, an adjustment to a thrust lever by a pilot or a command from an autopilot system. The data 454 can also include a detection of bleed air, an anticipated electrical load change, etc. To achieve the required thrust output and satisfy the power demands of the AC electrical system 300, the one or more processors 452 can determine a power sharing allocation.

[0076] The power sharing distribution can indicate whether and how much power is to be drawn from the first electric machine 310 and provided to its associated electrical loads 316A, 316B, 316C, and / or whether and how much power generated by the first electric machine 310 is to be provided to the second electrical pathway 342, e.g., for assisting the second electric machine 340 in driving the second spool 306 and / or providing power to one or more electrical loads 346A, 346B, 346C associated with the second electric machine 340. The power sharing distribution can also indicate whether and how much power is to be drawn from the second electric machine 340 and provided to its associated electrical loads 346A, 346B, 346C, and / or whether and how much power generated by the second electric machine 340 is to be provided to the first electrical pathway 312, e.g., for assisting the first electric machine 310 in driving the first spool 304 and / or providing power to one or more electrical loads 316A, 316B, 316C associated with the first electric machine 310. In this regard, the one or more processors 452 can determine a manner in which power is distributed throughout the AC electrical system 300 to meet the power and mechanical power demands of the gas turbine engine 302 and the carrier. The one or more processors 452 can control the bus tie contactors of the system 300 to achieve the desired power distribution.

[0077] As one example, the one or more processors 452 can determine that power generated by the second electric machine 340 is to be provided to the first electric machine 310, e.g., for core power assistance, where the first spool 304 is a high pressure spool of the gas turbine engine 302 and the second spool 306 is a low pressure spool of the gas turbine engine 302. Accordingly, in accordance with the determined power sharing distribution, the one or more processors 452 can cause power generated by the second electric machine 340 to be directed along the second electrical pathway 342 to the second AC bus 344. A portion of the power can be directed from the second AC bus 344 to the first electrical pathway 312 through the connection link 280. In this regard, the first bus tie contactor 282 and the second bus tie contactor 284 can be controlled to close to allow power to flow from the second electrical pathway 342 to the first electrical pathway 312. As the power passes through the power converter 292, the power converter 292 is controlled to synchronize the AC voltage and frequency of the power with the AC voltage and frequency of the first electrical pathway 312. In this manner, the generated alternating current has a synchronized voltage level, frequency, and phase with respect to the first electrical pathway 312, and thus, this converted power can be safely and effectively provided to the first AC bus 314 and onward to the first electric machine 310 for power assistance. As will be appreciated, the power provided to the first electric machine 310 can cause or assist the first electric machine 310 to drive the first spool 304.

[0078] Various embodiments will now be provided that disclose various ways in which one or more connection links can selectively electrically couple the first and second electrical passageways 312, 342.

[0079] In one example embodiment, as shown in Figure 5 The first electrical passageway 312 can include a main line 324 that electrically couples the first AC bus 314 to the first AC / DC converter 320. The first AC / DC converter 320 can be any suitable type of controllable device that is operable to convert alternating current to direct current, or vice versa. In some example embodiments, but not limited to, the first AC / DC converter 320 can be an automatic transformer rectifier unit (ATRU), an isolation transformer, or some other suitable converter device.

[0080] In addition, the main line 324 of the first electrical passageway 312 electrically couples the first AC / DC converter 320 to the first DC bus 322. Notably, the first AC / DC converter 320 is a bidirectional AC / DC converter. Thus, the first AC / DC converter 320 is operable to convert alternating current to direct current in some modes of operation, and to convert direct current to alternating current in some other modes of operation. In this way, when the first electric machine 310 is operating in a generator mode, alternating current can be converted to direct current and directed to the first DC bus 322. Conversely, when the first electric machine 310 is operating in a motor or drive mode, direct current from the first DC bus 322 can be converted to alternating current and directed to the first AC bus 314 and ultimately to the first electric machine 310 or other electrical load electrically coupled to the first AC bus 314.

[0081] The first load line 326 of the first electrical passageway 312 electrically couples the first DC bus 322 with the first load AC / DC converter 328, and electrically couples the first load AC / DC converter 328 with the electrical load 330. The first load AC / DC converter 328 is operable to convert direct current provided by the first DC bus 322 to alternating current. In this way, alternating current can be provided to the electrical load 330. In some embodiments, the first load AC / DC converter 358 is a bidirectional converter.

[0082] Similarly, a second load line 332 of the first electrical passageway 312 electrically couples the first DC bus 322 with a second load AC / DC converter 334, and electrically couples the second load AC / DC converter 334 with an electrical load 336. Much like the first load AC / DC converter 328, the second load AC / DC converter 334 is operable to convert direct current provided by the first DC bus 322 into alternating current. As a result, alternating current can be provided to the electrical load 336. In some embodiments, the second load AC / DC converter 334 is a bidirectional converter. As will be appreciated, in other example embodiments, more or less than two electrical loads can be associated with the first electrical passageway 312. Both the first load AC / DC converter 328 and the second load AC / DC converter 334 can be any suitable type of controllable device that is operable to convert alternating current into direct current, or vice versa. In some example embodiments, but not limited to, the first load AC / DC converter 328 and the second load AC / DC converter 334 can be an ATRU, an isolation transformer, or some other suitable converter device.

[0083] Still referring to Figure 5 , the second electrical passageway 342 electrically couples the second electric machine 340 to a second AC bus 344. The second AC bus 344 can be at a different voltage and at a different frequency than the first AC bus 314. One or more electrical loads 346 can be electrically coupled with the second AC bus 344, for example via a load line 348 of the second electrical passageway 342. The one or more electrical loads 346 can include, but are not limited to, an electrically driven pump, a computing component, a nacelle light, an air conditioning system, a nacelle air pressurization system, an electrically powered component associated with Figure 3 , the electric propulsion assembly 200 associated with the wind turbine 202, etc.

[0084] A main line 354 of the second electrical passageway 342 electrically couples the second AC bus 344 to a second AC / DC converter 350. The second AC / DC converter 350 can be any suitable type of controllable device that is operable to convert alternating current into direct current, or vice versa. In some example embodiments, but not limited to, the second AC / DC converter 350 can be an ATRU, an isolation transformer, or some other suitable converter device.

[0085] Further, the main line 354 of the second electrical passageway 342 also electrically couples the second AC / DC converter 350 to a second DC bus 352. The first DC bus 322 and the second DC bus 352, while for Figure 5The illustrated embodiments are separate elements, but collectively form a DC bus system 372. In some embodiments, the second AC / DC converter 350 is a bi-directional AC / DC converter. As such, when the second electric machine 340 is operating in a generator mode, alternating current can be converted to direct current and directed to the second DC bus 352. Conversely, when the second electric machine 340 is operating in a motor or drive mode, direct current from the second DC bus 352 can be converted to alternating current and directed to the second AC bus 344 and ultimately to the second electric machine 340. However, in other example embodiments, the second AC / DC converter 350 need not be a bi-directional AC / DC converter. For example, in some embodiments, the second AC / DC converter 350 can be a unidirectional AC / DC converter.

[0086] A first load line 356 of the second electrical passageway 342 electrically couples the second DC bus 352 with a first load AC / DC converter 358 and electrically couples the first load AC / DC converter 358 with an electrical load 360. Similarly, a second load line 362 of the second electrical passageway 342 electrically couples the second DC bus 352 with a second load AC / DC converter 364 and electrically couples the second load AC / DC converter 364 with an electrical load 366. As will be appreciated, in other example embodiments, more or less than two electrical loads can be associated with the second electrical passageway 342. Further, the first load AC / DC converter 358 and the second load AC / DC converter 364 can each be any suitable type of controllable device operable to convert alternating current to direct current, or vice versa. In some example embodiments, but not limited to, the first load AC / DC converter 358 and the second load AC / DC converter 364 can be an ATRU, an isolation transformer, or some other suitable converter device.

[0087] As Figure 5 Further illustrated, a first secondary line 368 of the second electrical passageway 342 electrically couples the second AC bus 344 with the first load line 356 of the second electrical passageway 342. As shown, the first secondary line 368 is electrically connected with the first load line 356 of the second electrical passageway 342 at a point between the first load AC / DC converter 358 and the electrical load 360. Similarly, a second secondary line 370 of the second electrical passageway 342 electrically couples the second AC bus 344 with the second load line 362 of the second electrical passageway 342. As shown, the second secondary line 370 is electrically connected with the second load line 362 of the second electrical passageway 342 at a point between the second load AC / DC converter 364 and the electrical load 366.

[0088] For Figure 5In the illustrated embodiment, as indicated, a DC bus link 380 can selectively electrically couple or connect a first DC bus 322 associated with a first electrical channel 312 and a second DC bus 352 associated with a second electrical channel 342. One or more bus tie contactors 382 of the DC bus link 380 can be controlled to selectively connect the first electrical channel 312 and the second electrical channel 342 at a DC level. In some operating modes, power can be transmitted between the first electrical channel 312 and the second electrical channel 342 via the DC bus link 380, so that power generated by the second electric machine 340 can be transmitted to the first electric machine 310, for example, for power assistance, and / or to the electrical loads 316, 330, 336 associated therewith. In other embodiments, power can be transmitted between the first electrical channel 312 and the second electrical channel 342 via the DC bus link 380, so that power generated by the first electric machine 310 can be transmitted to the second electric machine 340 and / or the electrical loads 348, 360, 366 associated therewith.

[0089] In other embodiments, the one or more connection links may include a single DC bus electrically connecting the first electrical channel 312 and the second electrical channel 342. In particular, in some example embodiments, Figure 5 The first DC bus 322 and the second DC bus 352 of the embodiment may be combined into a single DC bus. Figure 6 Such an embodiment is depicted. Figure 6 As shown, the AC electrical system 300 is similar to the AC electrical system 300 except that the DC bus system 372 includes a single DC bus 374 rather than two separate DC buses. Figure 5 The AC electrical system 300 is depicted in a similar manner. A single DC bus 374 is part of the first electrical channel 312 and the second electrical channel 342 and serves as a connecting link therebetween. In this regard, power can be transmitted between the first electrical channel 312 and the second electrical channel 342 via the single DC bus 374.

[0090] In some further embodiments, the AC electrical system 300 may include a connection link between the first AC / DC converter 320 and the second AC / DC converter 350 to electrically couple the first electrical channel 312 and the second electrical channel 342. For example, Figure 7As shown, the AC electrical system 300 includes a converter link 390 for selectively electrically coupling the first AC / DC converter 320 and the second AC / DC converter 350. The converter link 390 can include one or more tie breaker contacts 392 that can be controlled to selectively allow power to be transmitted from the second AC / DC converter 350 to the first AC / DC converter 320, or vice versa. Notably, the converter link 390 can be connected to the DC side of the second AC / DC converter 350 and the DC side of the first AC / DC converter 320. In this manner, power can be transmitted between the first and second AC / DC converters 320, 350 at a DC level, or in other words, as direct current power.

[0091] In other example embodiments, the AC electrical system 300 can include a connection link between the first AC bus 314 and the second AC bus 344 to electrically couple the first electrical passageway 312 and the second electrical passageway 342. Specifically, as shown in FIG. 4, Figure 8 As shown, the AC electrical system 300 includes an AC converter link 400 for selectively electrically coupling the first AC bus 314 and the second AC bus 344. Notably, the AC converter link 400 includes an AC / AC converter 402. In some embodiments, the AC / AC converter 402 can be a matrix converter, such as the matrix converter depicted in Figure 21 In other embodiments, the AC / AC converter 402 can be a cyclo-converter, such as the cyclo-converter depicted in Figure 22 Generally, the AC / AC converter 402 can be controlled to convert alternating current transmitted therethrough such that the current has a frequency and voltage that is synchronized with the AC bus to which power is being transmitted. As previously noted, the first AC bus 314 and the second AC bus 344 can have independent voltage levels, different frequencies, and can be out of phase with one another. Accordingly, the AC / AC converter 402 can facilitate safe and smooth transitions of power from one AC bus to another AC bus.

[0092] In other embodiments, as shown in FIG. 5, Figure 9 The AC electrical system 300 can include a plurality of connection links, including the DC bus link 380 of Figure 5 (or the single DC bus 374 of Figure 6 (not shown in FIG. 3), Figure 9 the converter link 390 of Figure 7 and the AC converter link 400 of Figure 8 Depending on mechanical and electrical requirements, power can be transmitted from one passageway to another passageway through one, some, or all of these connection links. It should be appreciated that any suitable combination of the above connection links is possible in other embodiments.

[0093] Referring again to Figure 5 An example manner in which the AC electrical system 300 can facilitate power sharing or power assist between spools of a gas turbine engine will now be described. The one or more processors 452 can initiate a power assist operation. The power assist operation can be initiated based at least in part on data 454 received by the one or more processors 452. The data 454 can indicate, for example, a required thrust output of the gas turbine engine 302. The required thrust output can be received in response to, for example, a pilot adjustment of a thrust lever or a command from an autopilot system. The data 454 can also include a detection of bleed air, an anticipated electrical load change, etc. To achieve the required thrust output and satisfy the power demands of the AC electrical system 300, the one or more processors 452 can determine a power sharing allocation. The power sharing allocation can indicate whether and how much power is to be drawn from the first electric machine 310, or whether and how much power is to be provided to the first electric machine 310, and whether and how much power is to be drawn from the second electric machine 340, or whether and how much power is to be provided to the second electric machine 340. In this regard, the one or more processors 452 can determine a manner in which power is distributed throughout the AC electrical system 300 to satisfy the power and mechanical power demands of the gas turbine engine 302 and the carrier. The one or more processors 452 can control controllable elements of the system 300 to achieve the desired power allocation.

[0094] For this example embodiment, the one or more processors 452 can determine that power generated by the second electric machine 340 is to be provided to the first electric machine 310, for example, for core power assist, where the first spool 304 is a high pressure spool of the gas turbine engine 302 and the second spool 306 is a low pressure spool of the gas turbine engine 302. Accordingly, in accordance with the determined power sharing allocation, the one or more processors 452 can cause power generated by the second electric machine 340 to be routed along the second electrical pathway 342 to the second AC bus 344. As shown, a portion of the power can be routed from the second AC bus 344 to the second AC / DC converter 350. Figure 5 The second AC / DC converter 350 can convert the alternating current to direct current. At least a portion of the direct current can be directed to the DC bus system 372, or more specifically, for this example embodiment, to the first DC bus 374.

[0095] The second AC / DC converter 350 can convert the alternating current to direct current. At least a portion of the direct current can be directed to the DC bus system 372, or more specifically, for this example embodiment, to the first DC bus 374. Figure 5In some embodiments, the DC power is received by the second DC bus 352. The one or more processors 452 can control one or more tie contactors 382 of the DC bus link 380 to allow power to flow from the second electrical passageway 342 to the first electrical passageway 312, or more specifically, for this embodiment, from the second DC bus 352 of the second electrical passageway 342 to the first DC bus 322 of the first electrical passageway 312. In this manner, DC power can be transmitted from the second DC bus 352 of the second electrical passageway 342 to the first DC bus 322 of the first electrical passageway 312 through the DC bus link 380.

[0096] The DC power is received by the first DC bus 322 and at least a portion of the DC level power is provided to the first AC / DC converter 320 where the DC power is converted to AC power. The first AC / DC converter 320 can convert the DC power such that the resulting AC power has a synchronized voltage level, frequency, and phase with respect to the first AC bus 314. The AC power is directed from the first AC / DC converter 320 to the first AC bus 314 and then to the first motor 310 to ultimately drive the first spool 304 and / or other electrical loads.

[0097] In some embodiments, the second AC / DC converter 350 is rated to handle the power demand requirements of the electrical loads 360, 366 associated with the second electrical passageway 342 and the power demand of the first motor 310. Accordingly, power need only be directed through the AC power system 300 as described above. However, in some embodiments, the second AC / DC converter 350 can not be rated to handle the power demand requirements of the electrical loads 360, 366 associated with the second electrical passageway 342 and the power demand of the first motor 310 at the same time. To meet the power demand requirements, power can be directed along one or more of the secondary lines 368, 370 such that one or more of the first load AC / DC converter 358 and the second load AC / DC converter 364 can assist the second AC / DC converter 350 in converting the AC level power to DC level power prior to transmission through the DC bus link 380. Examples of this are provided below.

[0098] Figure 10 is Figure 5a schematic diagram of an AC electrical system 300, and depicts an example manner in which power can be distributed through the AC electrical system 300, according to one example embodiment of the present disclosure. As shown, for this example embodiment, the second electrical machine 340 is operable to generate 300 kW, the second AC / DC converter 350 is rated at 200 kW, the electrical load 360 is loaded at 100 kW (i.e., the electrical load 360 requires 100 kW), the electrical load 366 is unloaded (i.e., the electrical load 366 requires 0 kW), and the first electrical machine 310 requires 200 kW. These numbers are for example purposes only.

[0099] Thus, for this example embodiment, 100 kW of the 300 kW of power generated by the second electrical machine 340 will be provided to the electrical load 360, and 200 kW of the 300 kW of power generated by the second electrical machine 340 will be provided to the first electrical machine 310. However, as noted above, the second AC / DC converter 350 is only rated at 200 kW, and thus, not all 300 kW can pass through the second AC / DC converter 350. Thus, for this example, the one or more processors 452 can control the system 300 such that 200 kW of power is directed through the second AC / DC converter 350, and such that 100 kW of power is directed from the second AC bus 344 along the second secondary line 370, as shown. Figure 10

[0100] The 200 kW of power directed through the second AC / DC converter 350 can be converted to DC level power, and directed to the second DC bus 352 of the DC bus system 372. The 100 kW of power directed through the second AC / DC converter 350 and through the second DC bus 352 can be directed along the first load line 356 to the first load AC / DC converter 358. The first load AC / DC converter 358 can convert the direct current to alternating current, and can direct the alternating current to the electrical load 360 to satisfy its required power. The additional 100 kW of power directed through the second AC / DC converter 350 can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 through the DC bus link 380, and along the first electrical passageway 312 to the first electrical machine 310.

[0101] ​To ensure that the first motor 310 receives its required 200 kW of power, 100 kW of power is directed from the second AC bus 344 along the second secondary line 370 to the second load line 362. Since the electrical load 366 is not loaded or does not require power, the second load line 362 can be used to supplement the power provided to the first motor 310. The 100 kW of power directed from the second AC bus 344 along the second secondary line 370 to the second load line 362 is directed through the second load AC / DC converter 364 to convert the alternating current to direct current. The DC level power is continued to be directed to the DC bus system 372. Then, as indicated, the direct current can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 through the DC bus link 380 and along the first electrical passageway 312 to the first motor 310. In this manner, the second load AC / DC converter 364 assists the second AC / DC converter 350 in converting the power to direct current for transmission through the DC bus link 380. Thus, 200 kW of power can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 and ultimately to the first motor 310.

[0102] In some alternative embodiments, the 200 kW of power directed through the second AC / DC converter 350 can be converted to DC level power and directed to the second DC bus 352 of the DC bus system 372. In such embodiments, all 200 kW of power directed through the second AC / DC converter 350 can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 through the DC bus link 380 and along the first electrical passageway 312 to the first motor 310. To satisfy the 100 kW power requirement of the electrical load 360, 100 kW of power can be directed from the second AC bus 344 along the first secondary line 368 to the first load line 356 and can be provided to the electrical load 360 to satisfy its power requirement. Thus, 200 kW of power can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 and ultimately to the first motor 310 to satisfy its required power while still satisfying the 100 kW power requirement of the electrical load 360.

[0103] As noted above, the DC level power can be transmitted from the second electrical passageway 342 to the first electrical passageway 312 through the DC bus link 380 for power sharing operations. Notably, in addition to or in the alternative to transmitting the DC level power through the DC bus link 380, the DC level power can be transmitted through a single DC bus 374 as shown in Figure 6 and / or through a plurality of DC buses 374 as shown in Figure 7The converter link 390 shown transfers power from the second electrical pathway 342 to the first electrical pathway 312. In addition to or in lieu of power transfer through the DC bus link 380, power transfer through such a connection link can be implemented. For example, in the example above regarding Figure 10 , in addition to Figure 5 the DC bus link 380, power can be transferred through the single DC bus 374 of Figure 6 and / or the converter link 390 from the second electrical pathway 342 to the first electrical pathway 312 of Figure 7 .

[0104] Further, in addition to or in lieu of DC level power transfer through the DC bus link 380 of Figure 8 , Figure 10 the single DC bus 374 of Figure 7 and / or the converter link 390, power can be transferred from the second electrical pathway 342 to the first electrical pathway 312 through an AC converter link 400 as shown in Figure 8 .

[0105] For example, in relation to the example of Figure 11 and with reference to Figure 11 and Figure 11 , 200 kW of power can be directed through the second AC / DC converter 350 described, and 100 kW can be directed to the electrical load 360, 100 kW can be directed through the DC bus link 380 to the first electrical pathway 312 and ultimately to the first motor 310. To satisfy the remaining 100 kW of the total 200 kW demand, 100 kW of power can be directed along the AC converter link 400. The AC level power can be converted by the AC / AC converter 402 to have a voltage level, frequency, and phase that is synchronized with the first AC bus 314. The converted AC level power can be provided to the first AC bus 314 and ultimately to the first motor 310. In this way, the 200 kW of power required by the first motor 310 can be received. For example, in some alternative embodiments, the 200 kW of power required can be directed through the AC converter link 400, and the 100 kW required by the electrical load 360 can be directed to the electrical load 360 via the first secondary line 368 and the first load line 365.

[0106] Figure 11 is a schematic diagram of an AC electrical system 300 for a vehicle in accordance with one example embodiment of the present disclosure, and depicts an example manner in which power can be transferred through the system 300 in response to a detected power generation failure.

[0107] In some example embodiments, the first electric machine 310 mechanically coupled to the first spool 304 of the gas turbine engine 302 can generate electrical power, for example such that the generated electrical power can be provided to one or more associated electrical loads 316, 330, 336. Further, the second electric machine 340 mechanically coupled to the second spool 306 of the gas turbine engine 302 can generate electrical power, for example such that the generated electrical power can be provided to one or more associated electrical loads 346, 360, 366. In such embodiments, the one or more processors 452 can receive data 456 indicating that a power generation failure associated with one of the electric machines has occurred. For example, in the illustrated embodiment, the data 456 indicates that a power generation failure associated with the second electric machine 340 has occurred (indicated by the “X” over the second electric machine 340). The power generation failure can indicate that the second electric machine 340 is not meeting the power demands of at least one of the electrical loads associated therewith. In some embodiments, the power generation failure can indicate that the second electric machine 340 is not meeting the power demands of any of the electrical loads associated therewith. Figure 12 In the illustrated embodiment, the data 456 indicates that a power generation failure associated with the second electric machine 340 has occurred (indicated by the “X” over the second electric machine 340). The power generation failure can indicate that the second electric machine 340 is not meeting the power demands of at least one of the electrical loads associated therewith. In some embodiments, the power generation failure can indicate that the second electric machine 340 is not meeting the power demands of any of the electrical loads associated therewith.

[0108] In response to the detected power generation failure associated with the second electric machine 340, the electrical power generated by the first electric machine 310 can be transmitted from the first electrical pathway 312 associated with the first electric machine 310 to the second electrical pathway 342 associated with the second electric machine 340 through one or more connection links. For example, in response to the detected power generation failure, the one or more processors 452 can control various elements of the system 300 to direct the electrical power generated by the first electric machine 310 along the first electrical pathway 312 to the first AC bus 314, through the first AC / DC converter 320 (wherein the AC level power is converted to DC level power), and through the DC bus system 372 to the second electrical pathway 342, as illustrated. Figure 13

[0109] ​A portion of the DC level power transmitted to the second electrical passageway 342 can be directed along their respective first load line 356 and second load line 362 to one or more of the electrical loads 360, 366, where the DC level power is converted by the respective first load AC / DC converter 358 and second load AC / DC converter 364 to provide AC level power to the electrical loads 360, 366. Another portion of the DC level power that has been transmitted through the DC bus system 372 can be directed to one or more electrical loads 346. In particular, the DC level power can be directed through the second AC / DC converter 350, where the DC level power is converted to AC level power. The AC level power is then directed to the second AC bus 344. The AC level power can then be directed along the load line 348 to one or more electrical loads 346. In this manner, the power generated by the first electrical machine 310 can be transmitted to the second electrical passageway 342 and used to satisfy the power demands of the electrical loads 346, 360, 366.

[0110] In some embodiments, as shown in FIG. 3, the DC bus system 372 includes a first DC bus 322 positioned along the first electrical passageway 312 and a second DC bus 352 positioned along the second electrical passageway 342. In such embodiments, the one or more connection links include a DC bus link 380. Accordingly, in such embodiments, the transmission of the power generated by the first electrical machine 310 from the first electrical passageway 312 associated with the first electrical machine 310 to the second electrical passageway 342 associated with the second electrical machine 340 through the one or more connection links includes directing the power from the first DC bus 322 to the second DC bus 352 in a DC level through the DC bus link 380, then to one or more AC / DC converters 350, 358, 364 of the second electrical passageway 342, and finally to one or more electrical loads 346, 360, 366. Figure 13 In some alternative embodiments, as shown in FIG. 4, the DC bus system 472 includes a first DC bus 422 positioned along the first electrical passageway 412 and a second DC bus 452 positioned along the second electrical passageway 442. In such embodiments, the one or more connection links include a DC bus link 480. Accordingly, in such embodiments, the transmission of the power generated by the first electrical machine 410 from the first electrical passageway 412 associated with the first electrical machine 410 to the second electrical passageway 442 associated with the second electrical machine 440 through the one or more connection links includes directing the power from the first DC bus 422 to the second DC bus 452 in a DC level through the DC bus link 480, then to one or more AC / DC converters 450, 458, 464 of the second electrical passageway 442, and finally to one or more electrical loads 446, 460, 466.

[0111] Figure 14 ​As shown, the DC bus system 372 includes a single DC bus 374 connected to the first electrical pathway 312 and the second electrical pathway 342. In such embodiments, the one or more connection links include the single DC bus 374. That is, the single DC bus 374 is the connection link between the pathways. Thus, in such embodiments, transmitting the power generated by the first electric machine 310 from the first electrical pathway 312 associated with the first electric machine 310 to the second electrical pathway 342 associated with the second electric machine 340 via the one or more connection links includes directing the power at a DC level through the single DC bus 374, and then to the one or more AC / DC converters 350, 358, 364 of the second electrical pathway 342, and ultimately to the one or more electrical loads 346, 360, 366.

[0112] In some other embodiments, as Figure 11 shown, the one or more connection links can include a converter link 390. Thus, in such embodiments, transmitting the power generated by the first electric machine 310 from the first electrical pathway 312 associated with the first electric machine 310 to the second electrical pathway 342 associated with the second electric machine 340 via the one or more connection links includes directing the power at a DC level from the first AC / DC converter 320 of the first electrical pathway 312 to the second AC / DC converter 350 of the second electrical pathway 342 via the converter link 390. In this manner, power can be provided to one or more electrical loads associated with the second electrical pathway 342, such as Figure 12 the electrical loads 346 depicted in FIG. 4.

[0113] In other example embodiments, as Figure 13 shown, the one or more connection links can include an AC converter link 400 having an AC / AC converter 402. In such embodiments, transmitting the power generated by the first electric machine 310 from the first electrical pathway 312 associated with the first electric machine 310 to the second electrical pathway 342 associated with the second electric machine 340 via the one or more connection links includes directing the power at an AC level from the first AC bus 314 of the first electrical pathway 312 through the AC / AC converter 402 to the second AC bus 344 of the second electrical pathway 342 via the AC converter link 400. In some embodiments, the AC / AC converter 402 is one of a matrix converter and a cycloconverter.

[0114] It will be appreciated that, in the event a power generation fault is detected, the above-described connection links (i.e., the single DC bus 374 of Figure 11 FIG. 4, in addition to or in lieu of the DC bus link 380 depicted in Figure 11 FIG. 4, Figure 11The converter link 390 and the AC converter link 400 can be used to transfer power between the first electrical passageway 312 and the second electrical passageway 342.

[0115] Now returning to FIG. 3, the target condition can be satisfied when the voltage level of the first AC bus 314 and the voltage level of the second AC bus 344 are within a predetermined range of each other (e.g., within five percent of each other). Figure 15 When the target condition is satisfied, the one or more processors 452 can control the bus tie contactors 412 of the AC bus link 410 to electrically couple the first AC bus 314 of the first electrical passageway 312 and the second AC bus 344 of the second electrical passageway 342. In this way, power can be transferred at an AC level from the first AC bus 314 directly to the second AC bus 344 and on to the one or more electrical loads 346, 360, 366 associated with the second electrical passageway 342. Figure 15 The dashed arrow in FIG. 3 depicts the transfer of power at an AC level from the first AC bus 314 directly to the second AC bus 344.

[0116] In some embodiments, the target condition is satisfied when power has been transferred through the one or more connection links for a predetermined time. By waiting for a period of time associated with the predetermined time before electrically coupling the first AC bus 314 with the second AC bus 344 via the AC bus link 410, the voltage level, frequency, and phase of the two passageways 312, 342 are allowed to synchronize via the one or more other connection links transferring power from the first electrical passageway 312 to the second electrical passageway 342. In other words, providing power first through the one or more other connection links before directly coupling the first AC bus 314 and the second AC bus 344 allows the voltage level and frequency of the second AC bus 344 to synchronize with the voltage level and frequency of the first AC bus 314 before directly electrically coupling the first AC bus 314 and the second AC bus 344 via the AC bus link 410. This also allows the phase of the first AC bus 314 and the second AC bus 344 to synchronize.

[0117] In other embodiments, the target condition is satisfied when the voltage level of the first AC bus 314 and the voltage level of the second AC bus 344 are within a predetermined range of each other (e.g., within five percent of each other). In some further embodiments, the target condition is satisfied when the frequency of the first AC bus 314 and the frequency of the second AC bus 344 are within a predetermined range of each other. One or more sensors at the first AC bus 314 and the second AC bus 344 can measure this characteristic and can provide the sensor readings to the one or more processors 452 so that the one or more processors 452 can determine when the target condition is satisfied.

[0118] When the target condition is satisfied, power can be transferred through the AC bus link 410 as described above, for example, as depicted by the dashed arrow in FIG. 3. Figure 16The dashed arrow in FIG. 6B illustrates that power generated by the first electric machine 170 can be transmitted to the second electric machine 190 via the AC bus link 410. This allows power to be transmitted from the first AC bus 314 to the second AC bus 344 via the AC bus link 410. In this manner, power transmission and distribution through the system 300 can be effectively achieved. In some embodiments, when the target condition is satisfied, power can be prevented from being transmitted to the second electrical passageway 342 through all other connection links except the AC bus link 410. In other embodiments, when the target condition is satisfied, power can continue to be transmitted to the second electrical passageway 342 through one or more connection links in addition to the AC bus link 410.

[0119] It should be appreciated that the propulsion system 50 and the AC electrical system 300 described above and depicted in the drawings are provided by way of example only, and that in other example embodiments, the propulsion system 50 and the AC electrical system 300 can have other suitable configurations. In certain example embodiments, for example Figure 16 In the example embodiment depicted in FIG. 6B, the turbine or core turbine engine 104 of the gas turbine engine 100 can include a high speed spool 160 in addition to the low speed spool 180. With this configuration, the low speed spool 180 can extend directly from the low speed turbine 118 to the fan 126, and the high speed spool 160 can drive the high speed compressor 112 with the high speed turbine 116.

[0120] Further, it should be appreciated that when the gas turbine engine includes three spools, as Figure 16 depicted in FIG. 6B, the AC electrical system can further include a third electric machine 178 mechanically coupled to a third spool 175 (e.g., a medium speed spool) of the gas turbine engine 100. A third electrical passageway can electrically couple the third electric machine 178 to a third AC bus. Further, with this configuration, the AC electrical system can further include one or more connection links that selectively electrically couple the third electrical passageway with the first electrical passageway, the second electrical passageway, or both, for example, in any of the example manners described herein. In this regard, power generated by the third electric machine 178 can be transmitted to the first electrical passageway, the second electrical passageway, or both, and further, power generated by the first electric machine 170 can be transmitted to the second electrical passageway, the third electrical passageway, or both, and further, power generated by the second electric machine 190 can be transmitted to the first electrical passageway, the third electrical passageway, or both.

[0121] Figure 5 A flowchart of a method 600 for transmitting power between spools of a gas turbine engine for power assisted operation is provided in accordance with one aspect of the present disclosure. For purposes of illustration and Figure 6Steps are depicted as being performed in a particular order. Those having ordinary skill in the art, using the disclosures provided herein, will appreciate that individual steps of any of the methods disclosed herein can be adjusted, modified, rearranged or improved in a variety of ways without departing from the scope of the present disclosure.

[0122] At 602, the method 600 includes determining a power sharing allocation for the electrically assisted operation. For example, one or more processors of the EMS can initiate the electrically assisted operation based at least in part on received data. The data can indicate a required thrust output of the gas turbine engine and a required power of the electrical loads of the gas turbine engine and the carrier. The power sharing allocation can indicate whether and how much power is to be drawn from the first electric machine, or whether and how much power is to be provided to the first electric machine, and whether and how much power is to be drawn from the second electric machine, or whether and how much power is to be provided to the second electric machine.

[0123] At 604, again with reference to Figure 7 , the method 600 includes transmitting, on the AC electrical system of the carrier, power generated by a second electric machine mechanically coupled to a second spool of the gas turbine engine to a first electric machine mechanically coupled to a first spool of the gas turbine engine. For example, the carrier can be an aircraft. In some embodiments, the transmitting power at 604 includes at least one of: i) directing power from the second electric machine along a second electrical pathway to a second AC bus positioned along the second electrical pathway, through a second AC / DC converter positioned along the second electrical pathway, to the first electrical pathway at a DC level through one or more connection links, through the first AC / DC converter to the first AC bus, and on to the first electric machine; and ii) directing power from the second AC bus at an AC level through an AC / AC converter positioned along an AC converter link electrically coupling the first AC bus and the second AC bus, and on to the first AC bus and the first electric machine.

[0124] In yet another embodiment, the AC electrical system has a DC bus system including a first DC bus positioned along the first electrical pathway and a second DC bus positioned along the second electrical pathway. In such an embodiment, the one or more connection links include a DC bus link, for example, as shown in Figure 8 Furthermore, in such an embodiment, the transmitting power from the second electric machine to the first electric machine includes directing power from the second DC bus to the first DC bus at a DC level through the DC bus link, and then to the first AC / DC converter, for example, to convert back to alternating current before being directed to the first AC bus and ultimately to the first electric machine.

[0125] In some further embodiments, the AC electrical system has a DC bus system comprising a single DC bus connected to the first electrical channel and the second electrical channel. In such embodiments, one or more connecting links comprise a single DC bus, e.g., Figure 9 As shown, and wherein transmitting power includes directing power at DC levels through a single DC bus.

[0126] In some embodiments, one or more connection links include a converter link, e.g. Figure 17 In such an embodiment, the transmitting includes directing power from the second AC / DC converter to the first AC / DC converter at a DC level through the converter link.

[0127] In other embodiments, transferring power from the second electric machine to the first electric machine includes directing power at an AC level from the second AC bus through an AC / AC converter positioned along an AC converter link electrically coupling the first AC bus and the second AC bus, e.g., Figure 17 As shown, and continues to the first AC bus and the first motor. In some embodiments, the AC / AC converter is one of a matrix converter and a cycloconverter.

[0128] In some further embodiments, transferring power from the second motor to the first motor includes directing power at a DC level and an AC level through a plurality of connection links, e.g., Figure 11 shown.

[0129] Furthermore, in other embodiments, the second electrical channel has a load line that electrically couples the load AC / DC converter to the DC bus system and electrically couples the load AC / DC converter to the electrical load. The second electrical channel has a secondary line that electrically connects the second AC bus to the load line at a point between the load AC / DC converter and the electrical load. In such embodiments, transferring power generated by the second electric machine to the first electric machine includes directing power along the secondary line, through the load AC / DC converter and to the DC bus system, through at least one of the one or more connecting links from the second electrical channel to the first electrical channel, and along the first electrical channel to the first electric machine.

[0130] Figure 12 A flow chart of a method 700 of transmitting power through an AC electrical system of a vehicle according to one aspect of the present disclosure is provided. For purposes of illustration and discussion, Figure 13 The steps are depicted as being performed in a specific order. One of ordinary skill in the art using the disclosure provided herein will appreciate that the individual steps of any method disclosed herein may be adjusted, modified, rearranged, or improved in various ways without departing from the scope of the present disclosure.

[0131] At 702, the method 700 includes generating electrical power by a first electric machine mechanically coupled to a first spool of a gas turbine engine. For example, the gas turbine engine can be a multi-spool gas turbine engine for an aircraft. In some implementations, the gas turbine engine can be a dual-spool gas turbine engine having a first spool and a second spool. In other implementations, the gas turbine engine can include more than two spools.

[0132] At 704, the method 700 includes generating electrical power by a second electric machine mechanically coupled to a second spool of the gas turbine engine. In this regard, the first electric machine generates electrical power at 702 and the second electric machine generates electrical power at 704. For example, the electrical power generated by the first electric machine and the second electric machine can be directed to their respective electrical loads.

[0133] At 706, the method 700 includes, in response to a detected electrical generation failure associated with the second electric machine, transmitting the electrical power generated by the first electric machine from a first electrical pathway associated with the first electric machine to a second electrical pathway associated with the second electric machine via one or more connection links. For example, the one or more processors can receive data indicating that an electrical generation failure associated with the second electric machine has occurred. The electrical generation failure can indicate that the second electric machine is not meeting the power demands of at least one electrical load associated therewith. Accordingly, to ensure that the power demands of the at least one electrical load associated with the second electric machine are met, the electrical power generated by the first electric machine can be transmitted from the first electrical pathway to the second electrical pathway via one or more connection links, such as any of the connection links disclosed herein.

[0134] For example, in some implementations, the AC electrical system has a DC bus system including a first DC bus positioned along the first electrical pathway and a second DC bus positioned along the second electrical pathway. In such implementations, the one or more connection links include a DC bus link, such as illustrated in FIG. 8, for example. Accordingly, transmitting the electrical power generated by the first electric machine from the first electrical pathway associated with the first electric machine to the second electrical pathway associated with the second electric machine via the one or more connection links includes directing the electrical power from the first DC bus to the second DC bus at a DC level via the DC bus link, and then to one or more AC / DC converters of the second electrical pathway. Figure 14

[0135] In some further implementations, the AC electrical system has a DC bus system including a single DC bus connected to the first electrical pathway and the second electrical pathway. The one or more connection links include the single DC bus, such as illustrated in FIG. 9, for example. Accordingly, transmitting the electrical power generated by the first electric machine from the first electrical pathway associated with the first electric machine to the second electrical pathway associated with the second electric machine via the one or more connection links includes directing the electrical power from the first DC bus to the second DC bus at a DC level via the single DC bus, and then to one or more AC / DC converters of the second electrical pathway. Figure 18 ​As shown. In such embodiments, transmitting the power generated by the first electric machine from the first electrical pathway associated with the first electric machine to the second electrical pathway associated with the second electric machine via the one or more connection links includes directing the power at a DC level via a single DC bus and then to one or more AC / DC converters of the second electrical pathway.

[0136] In some embodiments, the one or more connection links include a converter link, for example, as shown in Figure 18 As shown. In such embodiments, transmitting the power at 706 includes directing the power at a DC level from the first AC / DC converter of the first electrical pathway to the second AC / DC converter of the second electrical pathway via the converter link. As previously mentioned, the power can be transmitted at a DC level, or in other words, as direct current, via the converter link.

[0137] In other example embodiments, the one or more connection links include an AC converter link having an AC / AC converter, for example, as shown in Figures 19 to 22 As shown. In such embodiments, transmitting the power generated by the first electric machine from the first electrical pathway associated with the first electric machine to the second electrical pathway associated with the second electric machine via the one or more connection links includes directing the power at an AC level from the first AC bus of the first electrical pathway and through the AC / AC converter to the second AC bus of the second electrical pathway via the AC converter link. In some embodiments, the AC / AC converter is one of a matrix converter and a cycloconverter.

[0138] At 708, the method 700 includes electrically coupling the first AC bus of the first electrical pathway and the second AC bus of the second electrical pathway with the AC bus link when a target condition is satisfied, thereby transmitting the power from the first AC bus to the second AC bus at an AC level and continuing to one or more electrical loads associated with the second electrical pathway. In some embodiments, the first AC bus and the second AC bus are directly electrically connected. In this way, power can be more efficiently transmitted from one electrical pathway to another.

[0139] In some embodiments, the target condition is satisfied when the power has been transmitted via the one or more connection links for a predetermined time. In other embodiments, the target condition is satisfied when a voltage level of the first AC bus and a voltage level of the second AC bus are within a predetermined range of each other (e.g., within five percent of each other). In some further embodiments, the target condition is satisfied when a frequency of the first AC bus and a frequency of the second AC bus are within a predetermined range of each other.

[0140] Figure 19An example computing system 800 is provided according to an example embodiment of the present disclosure. The computing elements or systems described herein may include one, some, or all of the components of computing system 800 and may perform the operations described below.

[0141] like Figure 6 As shown, computing system 800 may include one or more computing devices 810. Computing device 810 may include one or more processors 810A and one or more memory devices 810B. The one or more processors 810A may include any suitable processing device, such as a microprocessor, a microcontroller, an integrated circuit, a logic device, and / or other suitable processing device. The one or more memory devices 810B may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, a hard drive, a flash drive, and / or other memory devices.

[0142] One or more memory devices 810B may store information accessible by one or more processors 810A, including computer-executable or computer-readable instructions 810C that may be executed by one or more processors 810A. The instructions 810C may be any set of instructions that, when executed by the one or more processors 810A, causes the one or more processors 810A to perform operations. In some embodiments, the instructions 810C may be executed by the one or more processors 810A to cause the one or more processors 810A to perform operations, such as any operations and functions for which the computing system 800 and / or computing device 810 is configured. The instructions 810C may be software written in any suitable programming language or may be implemented in hardware. Additionally and / or alternatively, the instructions 810C may be executed in logically and / or virtually separate threads on the processor 810A. The memory device 810B may further store data 810D that may be accessed by the processor 810A.

[0143] The computing device 810 may also include a network interface 810E for communicating with other components of the system 800, for example (e.g., via a network). The network interface 810E may include any suitable components for interfacing with one or more networks, including, for example, a transmitter, a receiver, a port, a controller, an antenna, and / or other suitable components. One or more controllable devices (e.g., a bus contactor, a power converter, etc.) may be configured to receive one or more commands from the computing device 810 or to provide one or more commands to the computing device 810.

[0144] The technology discussed herein makes reference to computer-based systems, actions taken by and information sent to and from computer-based systems. One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations, combinations, and divisions of tasks and functionality between and among components. For example, processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memories, instructions, and applications can be embodied on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0145] Figure 5 Various circuit diagrams are provided that depict example ways in which the first AC bus 314 can be electrically coupled with the second AC bus 344.

[0146] Figure 7 Circuit diagrams are depicted for voltage source DC link converter implementations in which the first AC bus 314 of the first electrical passageway 312 is electrically coupled with the second AC bus 344 of the second electrical passageway 342 via a voltage DC bus. As shown, the first AC bus 314 is electrically connected to a first AC / DC converter 320. That is, wires associated with respective phases a, b, c electrically connect the first AC bus 314 with different levels or legs of the first AC / DC converter 320. The first AC / DC converter 320 is a multi-level converter having a plurality of diodes and switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc.

[0147] The first AC / DC converter 320 is electrically connected to a single DC bus 374 (associated with the single DC bus 374 of Figure 19 ). The single DC bus 374 has a capacitor C2 to maintain the DC bus voltage constant or nearly constant. The DC bus 374 is electrically connected to a second AC / DC converter 350. That is, wires associated with respective phases A, B, C electrically connect the second AC bus 344 with different levels or legs of the second AC / DC converter 350. Like the first AC / DC converter 320, the second AC / DC converter 350 is a multi-level converter having a plurality of diodes and switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc. It will be appreciated that in other DC bus system embodiments disclosed herein (e.g., embodiments in which the DC bus system includes separate DC buses as shown in Figure 20 and / or in which power is transmitted through a converter link 390 as shown in Figure 6 ), the first AC bus 314 can be electrically coupled with the second AC bus 344 via a DC bus as shown in Figure 5The illustrated voltage DC bus is electrically coupled with the second AC bus 344.

[0148] Figure 7 A circuit diagram is depicted for a current source DC link converter implementation in which the first AC bus 314 of the first electrical passageway 312 is electrically coupled with the second AC bus 344 of the second electrical passageway 342 via a current DC bus. As illustrated, the first AC bus 314 is electrically connected to a first AC / DC converter 320. In other words, wires associated with respective phases a, b, c electrically connect the first AC bus 314 with different levels or legs of the first AC / DC converter 320. The first AC / DC converter 320 is a multi-level converter having a plurality of diodes and switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc.

[0149] The first AC / DC converter 320 is electrically connected to a single DC bus 374 (associated with the Figure 20 ). The single DC bus 374 has an inductor L2 to keep the DC bus current constant or nearly constant. The DC bus 374 is electrically connected to a second AC / DC converter 350. In other words, wires associated with respective phases A, B, C electrically connect the second AC bus 344 with different levels or legs of the second AC / DC converter 350. The second AC / DC converter 350 is a multi-level converter having a plurality of diodes and switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc. It will be appreciated that in other DC bus system embodiments disclosed herein (e.g., embodiments in which the DC bus system includes separate DC buses as Figure 21 illustrated and / or in which power is transmitted through a converter link 390 as Figure 8 illustrated), the first AC bus 314 can be electrically coupled with the second AC bus 344 via a current DC bus as Figure 9 illustrated.

[0150] Figure 14A circuit diagram is depicted for a matrix converter embodiment in which a first AC bus 314 of a first electrical passageway 312 is electrically coupled with a second AC bus 344 of a second electrical passageway 342 via an AC converter link 400 in which an AC / AC matrix converter 402A is positioned. As shown, the AC / AC matrix converter 402A includes a plurality of switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc. For this embodiment, the AC / AC matrix converter 402A can perform voltage and current conversion in a single stage for the three phases depicted. The AC / AC matrix converter 402A is operable to convert AC level power flowing along the AC converter link 400 to be in synchronism with the voltage level, frequency, and phase associated with the AC bus to which the AC level power is directed. For example, the AC / AC matrix converter 402A can be implemented as an AC / AC converter 402 for embodiments of Figure 22 , Figure 8 , Figure 9 .

[0151] Figure 14 A circuit diagram is depicted for a matrix converter embodiment in which a first AC bus 314 of a first electrical passageway 312 is electrically coupled with a second AC bus 344 of a second electrical passageway 342 via an AC converter link 400 in which an AC / AC matrix converter 402A is positioned. As shown, the AC / AC matrix converter 402A includes a plurality of switching elements. The switching elements can be any suitable type of switching element, such as insulated gate bipolar transistors, power MOSFETs, etc. For this embodiment, the AC / AC matrix converter 402A can perform voltage and current conversion in a single stage for the three phases depicted. The AC / AC matrix converter 402A is operable to convert AC level power flowing along the AC converter link 400 to be in synchronism with the voltage level, frequency, and phase associated with the AC bus to which the AC level power is directed. For example, the AC / AC matrix converter 402A can be implemented as an AC / AC converter 402 for embodiments of ​ , ​ , ​ .

[0152] Although specific features of various embodiments can be shown in some drawings and not in other drawings, this is for convenience only. Aspects of any drawing can be referenced and / or claimed in combination with aspects of any other drawing in accordance with the principles of the present disclosure.

[0153] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0154] Further aspects are provided by the subject matter of the following clauses:

[0155] 1. An AC electrical system for a carrier, comprising: a first electric machine mechanically coupled with a first spool of a gas turbine engine; a second electric machine mechanically coupled with a second spool of the gas turbine engine; a first AC bus; a second AC bus; a first electrical passageway electrically coupling the first electric machine to the first AC bus; a second electrical passageway electrically coupling the second electric machine to the second AC bus; one or more connection links selectively electrically coupling the first electrical passageway and the second electrical passageway; and one or more power converters operable to convert power transmitted between the first electrical passageway and the second electrical passageway through the one or more connection links such that power generated by the second electric machine can be transmitted to the first electrical passageway, or such that power generated by the first electric machine can be transmitted to the second electrical passageway.

[0156] 2. The AC electrical system of any preceding clause, further comprising: a DC bus system; a first AC / DC converter, the first AC / DC converter being a bidirectional AC / DC converter; and a second AC / DC converter, and wherein the first electrical passageway electrically couples the first AC bus to the first AC / DC converter and electrically couples the first AC / DC converter to the DC bus system, and wherein the second electrical passageway electrically couples the second AC bus to the second AC / DC converter and electrically couples the second AC / DC converter to the DC bus system.

[0157] 3. The AC electrical system of any preceding clause, wherein the DC bus system comprises a first DC bus positioned along the first electrical passageway and a second DC bus positioned along the second electrical passageway, and wherein the one or more connection links comprises a DC bus link for selectively electrically coupling the first DC bus and the second DC bus of the DC bus system.

[0158] 4. The AC electrical system of any preceding clause, wherein the DC bus system comprises a single DC bus, and wherein the one or more connection links comprise the single DC bus for selectively electrically coupling the first electrical passageway and the second electrical passageway.

[0159] 5. The AC electrical system of any preceding clause, wherein the DC bus system is one of a voltage DC bus and a current DC bus.

[0160] 6. The AC electrical system of any preceding clause, further comprising: a first AC / DC converter; and a second AC / DC converter, and wherein the one or more connection links comprise a converter link for selectively electrically coupling the first AC / DC converter and the second AC / DC converter.

[0161] 7. The AC electrical system of any preceding clause, wherein the one or more connection links comprise an AC converter link for selectively electrically coupling the first AC bus and the second AC bus, the AC converter link comprising an AC / AC converter.

[0162] 8. The AC electrical system of any preceding clause, wherein the AC / AC converter is a matrix converter.

[0163] 9. The AC electrical system of any preceding clause, wherein the AC / AC converter is a cycloconverter.

[0164] 10. The AC electrical system of any preceding clause, wherein: i) the first spool is a high voltage spool and the second spool is a low voltage spool; or ii) the first spool is the low voltage spool and the second spool is the high voltage spool.

[0165] 11. The AC electrical system of any preceding clause, further comprising: one or more processors configured to cause power generated by the second electrical machine to be transmitted from the second electrical passageway to the first electrical passageway and the first electrical machine through at least one of the one or more connection links based at least in part on a power sharing allocation for a power assist operation.

[0166] 12. The AC electrical system of any preceding clause, further comprising: a DC bus system; a first AC / DC converter, the first AC / DC converter being a bidirectional AC / DC converter; and a second AC / DC converter, and wherein the first electrical pathway electrically couples the first AC bus to the first AC / DC converter and electrically couples the first AC / DC converter to the DC bus system, and wherein the second electrical pathway electrically couples the second AC bus to the second AC / DC converter and electrically couples the second AC / DC converter to the DC bus system, and wherein the second electrical pathway has a load line that electrically couples a load AC / DC converter to the DC bus system and electrically couples the load AC / DC converter to an electrical load, and wherein the second electrical pathway has a secondary line that electrically connects the second AC bus with the load line at a point between the load AC / DC converter and the electrical load.

[0167] 13. The AC electrical system of any preceding clause, wherein the one or more processors are further structured to cause power generated by the second electrical machine to be transmitted along the secondary line, through the load AC / DC converter to the DC bus system, from the second electrical pathway to the first electrical pathway through the at least one of the one or more connection links, and along the first electrical pathway to the first electrical machine based at least in part on the power sharing allocation for the power assist operation.

[0168] 14. The AC electrical system of any preceding clause, wherein the first spool is a mid-pressure spool and the second spool is one of a low-pressure spool and a high-pressure spool of the gas turbine engine.

[0169] 15. A method comprising: transmitting, on an AC electrical system of a carrier, power generated by a second electrical machine mechanically coupled to a second spool of a gas turbine engine to a first electrical machine mechanically coupled to a first spool of the gas turbine engine, and wherein the transmitting comprises at least one of: i) directing power from the second electrical machine along a second electrical pathway to a second AC bus positioned along the second electrical pathway, through a second AC / DC converter positioned along the second electrical pathway, through one or more connection links to a first electrical pathway at a DC level, through a first AC / DC converter to a first AC bus, and on to the first electrical machine; and ii) directing power from the second AC bus through an AC / AC converter positioned along an AC converter link electrically coupling the first AC bus and the second AC bus at an AC level, and on to the first AC bus and the first electrical machine.

[0170] 16. The method of any preceding clause, wherein the one or more connection links comprise a converter link, wherein the transferring comprises directing power from the second AC / DC converter to the first AC / DC converter at the DC level through the converter link.

[0171] 17. The method of any preceding clause, wherein the AC electrical system has a DC bus system comprising a first DC bus positioned along the first electrical pathway and a second DC bus positioned along the second electrical pathway, and wherein the one or more connection links comprise a DC bus link, and wherein the transferring comprises directing power from the second DC bus to the first DC bus at the DC level through the DC bus link, and then to the first AC / DC converter.

[0172] 18. The method of any preceding clause, wherein the AC electrical system has a DC bus system comprising a single DC bus connected to the first electrical pathway and the second electrical pathway, and wherein the one or more connection links comprise the single DC bus, and wherein the transferring comprises directing power at the DC level through the single DC bus.

[0173] 19. The method of any preceding clause, wherein the transferring further comprises directing power from the second AC bus at the AC level through the AC / AC converter positioned along the AC converter link electrically coupling the first AC bus and the second AC bus, and continuing to the first AC bus and the first motor.

[0174] 20. The method of any preceding clause, wherein the AC / AC converter is one of a matrix converter and a cycloconverter.

[0175] 21. The method of any preceding clause, wherein the second electrical pathway has a load line electrically coupling a load AC / DC converter to a DC bus system and electrically coupling the load AC / DC converter to an electrical load, and wherein the second electrical pathway has a secondary line electrically connecting the second AC bus with the load line at a point between the load AC / DC converter and the electrical load, and wherein the transferring further comprises directing power along the secondary line, through the load AC / DC converter to the DC bus system, through the at least one of the one or more connection links from the second electrical pathway to the first electrical pathway, and along the first electrical pathway to the first motor.

[0176] 22. A method of transmitting power through an AC electrical system of a carrier, the method comprising: generating power through a first electric machine mechanically coupled with a first spool of a gas turbine engine; generating power through a second electric machine mechanically coupled with a second spool of the gas turbine engine; in response to a detected power generation failure associated with the second electric machine, transmitting power generated by the first electric machine from a first electrical pathway associated with the first electric machine to a second electrical pathway associated with the second electric machine through one or more connection links; and when a target condition is satisfied, electrically coupling a first AC bus of the first electrical pathway and a second AC bus of the second electrical pathway with an AC bus link, thereby transmitting power from the first AC bus to the second AC bus at an AC level and continuing to one or more electrical loads associated with the second electrical pathway.

[0177] 23. The method of any preceding clause, wherein the one or more connection links comprise a converter link, wherein the transmitting comprises directing power from a first AC / DC converter of the first electrical pathway to a second AC / DC converter of the second electrical pathway at a DC level through the converter link.

[0178] 24. The method of any preceding clause, wherein the AC electrical system has a DC bus system comprising a first DC bus positioned along the first electrical pathway and a second DC bus positioned along the second electrical pathway, and wherein the one or more connection links comprise a DC bus link, and wherein the transmitting comprises directing power from the first DC bus to the second DC bus at a DC level through the DC bus link and then to one or more AC / DC converters of the second electrical pathway.

[0179] 25. The method of any preceding clause, wherein the AC electrical system has a DC bus system comprising a single DC bus connected to the first electrical pathway and the second electrical pathway, and wherein the one or more connection links comprise the single DC bus, and wherein the transmitting comprises directing power through the single DC bus at a DC level and then to one or more AC / DC converters of the second electrical pathway.

[0180] 26. The method of any preceding clause, wherein the one or more connection links comprise an AC converter link having an AC / AC converter, and wherein the transmitting comprises directing power from the first AC bus of the first electrical pathway at an AC level through the AC converter link and through the AC / AC converter to the second AC bus of the second electrical pathway.

[0181] 27. The method of any preceding clause, wherein the AC / AC converter is one of a matrix converter and a cyclo-converter.

[0182] 28. The method of any preceding clause, wherein the target condition is satisfied when power has been transmitted over the one or more connection links for a predetermined time.

[0183] 29. The method of any preceding clause, wherein the target condition is satisfied when a voltage level of the first AC bus and a voltage level of the second AC bus are within a predetermined range of each other.

[0184] 30. The method of any preceding clause, wherein the target condition is satisfied when a frequency of the first AC bus and a frequency of the second AC bus are within a predetermined range of each other.

[0185] 31. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by one or more processors of a computing system of a vehicle, cause the one or more processors to: cause power generated by a second electric machine mechanically coupled to a second spool of a gas turbine engine to be transmitted to a second AC bus electrically coupled to the second electric machine; cause power transmitted to the second AC bus to be transmitted to one or more power converters to convert the power; and cause the power converted by the one or more power converters to be transmitted to a first AC bus electrically coupled to a first electric machine mechanically coupled to a first spool of the gas turbine engine.

[0186] 32. A method comprising: transmitting, on an AC electrical system of a vehicle, power generated by a second electric machine mechanically coupled to a second spool of a gas turbine engine to a first electric machine mechanically coupled to a first spool of the gas turbine engine, and wherein the transmitting comprises at least one of: i) directing power from the second electric machine along a second electrical pathway to a second AC bus positioned along the second electrical pathway, through a second AC / DC converter positioned along the second electrical pathway, through one or more connection links to a first electrical pathway at a DC electrical level, through a first AC / DC converter to a first AC bus; and ii) directing power from the second AC bus at an AC electrical level through an AC / AC converter positioned along an AC converter link electrically coupling the first AC bus and the second AC bus, and continuing to the first AC bus.

[0187] 33. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by one or more processors of a computing system of a vehicle, cause the one or more processors to: cause power generated by a second electric machine mechanically coupled to a second spool of a gas turbine engine to be transmitted through an AC electrical system of the vehicle to a first electric machine mechanically coupled to a first spool of the gas turbine engine, and wherein, in causing power generated by the second electric machine to be transmitted to the first electric machine, the one or more processors cause at least one of: i) directing power from the second electric machine along a second electrical pathway to a second AC bus positioned along the second electrical pathway, through a second AC / DC converter positioned along the second electrical pathway, through one or more connection links at a DC electrical level to a first electrical pathway, through a first AC / DC converter to a first AC bus, and onward to the first electric machine; and ii) directing power from the second AC bus at an AC electrical level through an AC / AC converter positioned along an AC link electrically coupling the first AC bus and the second AC bus, and onward to the first AC bus and the first electric machine.

[0188] 34. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by one or more processors of a computing system of a vehicle, cause the one or more processors to: cause a first electric machine mechanically coupled to a first spool of a gas turbine engine to generate power; cause a second electric machine mechanically coupled to a second spool of the gas turbine engine to generate power; in response to a detected power generation failure associated with the second electric machine, cause power generated by the first electric machine to be transmitted from a first electrical pathway associated with the first electric machine to a second electrical pathway associated with the second electric machine through one or more connection links; and when a target condition is satisfied, cause a first AC bus of the first electrical pathway to be directly electrically coupled to a second AC bus of the second electrical pathway such that power is transmitted from the first AC bus to the second AC bus at an AC electrical level and onward to one or more electrical loads associated with the second electrical pathway.

[0189] 35. An AC electrical system for a carrier, comprising: a first electric machine mechanically coupled with a first spool of a gas turbine engine; a second electric machine mechanically coupled with a second spool of the gas turbine engine; a first AC bus; a second AC bus; a first electrical passageway electrically coupling the first electric machine to the first AC bus; a second electrical passageway electrically coupling the second electric machine to the second AC bus; one or more connection links selectively electrically coupling the first electrical passageway and the second electrical passageway; one or more power converters operable to convert electrical power; and one or more processors structured to: cause the first electric machine to generate electrical power; cause the second electric machine to generate electrical power; in response to a detected power generation failure associated with the second electric machine, cause the electrical power generated by the first electric machine to be converted by the one or more power converters and transmitted from the first electrical passageway associated with the first electric machine to the second electrical passageway associated with the second electric machine through the one or more connection links; and when a target condition is satisfied, cause the first AC bus of the first electrical passageway to be directly electrically coupled with the second AC bus of the second electrical passageway, thereby transmitting electrical power from the first AC bus to the second AC bus at an AC level.

Claims

1. A method, characterized in that include: transmitting, over the vehicle's AC electrical system, electrical power generated by a second electric machine mechanically coupled to a second spool of the gas turbine engine to a first electric machine mechanically coupled to a first spool of the gas turbine engine, and wherein the transmitting comprises directing power from the second motor along a second electrical path to a second AC bus positioned along the second electrical path, through a second AC / DC converter positioned along the second electrical path, and at a DC level to a DC electrical load of the vehicle through one or more connecting links.

2. The method according to claim 1, characterized in that wherein said transmitting of said electric power further comprises: Power is directed from the one or more connection links at a DC level through a first AC / DC converter and on to the first electric machine.

3. The method of claim 1 , wherein the transmitting of the power further comprises: Power is directed at an AC level from the second AC bus to an AC / AC converter positioned along an AC converter link electrically coupled to the first AC bus and on to the first AC bus and the first electric machine.

4. The method of claim 3, wherein the AC / AC converter is one of a matrix converter and a cycloconverter. 5 . The method of claim 1 , wherein the DC electrical load of the vehicle comprises at least one of a local load and / or a vehicle load.

6. The method of claim 1, wherein the DC electrical load of the vehicle comprises at least one of an electrically driven pump, a computing component, a motor, a cabin light, an air conditioning system, or a cabin air pressurization system.

7. The method of claim 1, wherein the one or more connection links include a converter link, wherein the transmitting includes directing power at a DC level from the second AC / DC converter to the first AC / DC converter through the converter link.

8. The method of claim 1 , wherein the AC electrical system has a DC bus system comprising a first DC bus positioned along the first electrical pathway and a second DC bus positioned along the second electrical pathway, and wherein the one or more connecting links comprise a DC bus link, and wherein the transmitting comprises directing power at a DC level from the second DC bus to the first DC bus and then to the first AC / DC converter.

9. The method of claim 1 , wherein the AC electrical system has a DC bus system comprising a single DC bus connected to a first electrical channel and a second electrical channel, and wherein the one or more connecting links comprise the single DC bus, the transmitting comprising directing electrical power at the DC level through the single DC bus.

10. The method of claim 1, wherein the second AC / DC converter is a bidirectional AC / DC converter.

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