Electric propulsion system

Abstract

A propulsion system includes an electric thruster and a gas turbine engine. The propulsion system also includes an electric motor coupled to a rotating component of the gas turbine engine, which generates a voltage at a baseline voltage amplitude during operation of the gas turbine engine. An electrical communication bus is provided to electrically connect the electric motor to the electric thruster. The propulsion system also includes devices for providing the electric thruster with a differential voltage approximately twice the baseline voltage amplitude.

Description

Technical Field

[0001] This topic broadly relates to electric propulsion systems used in aviation devices. Background Technology

[0002] A typical aircraft propulsion system comprises one or more gas turbine engines. For some propulsion systems, a gas turbine engine generally comprises a fan and a core arranged in flow communication with each other. Furthermore, the core of the gas turbine engine generally comprises a compressor section, a combustion section, a turbine section, and an exhaust section arranged in a series flow sequence. In operation, air is supplied from the fan to the inlet of the compressor section, where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are then conveyed from the combustion section to the turbine section. The fuel flow through the turbine section drives the turbine section and is then conveyed through the exhaust section, for example, to the atmosphere.

[0003] For some aircraft, it may be advantageous to include an electric fan in the propulsion system to supplement the propulsive power provided by one or more gas turbine engines included in the propulsion system. However, providing the aircraft with sufficient energy storage to power the electric fan may be infeasible in terms of space and weight. It is worth noting that some gas turbine engines may include, for example, auxiliary generators located within the gas turbine engine's cowling. However, these auxiliary generators are not configured to provide sufficient electrical energy to adequately drive the electric fan.

[0004] Therefore, a propulsion system for an aircraft having one or more gas turbine engines and a generator capable of supplying the desired amount of electrical energy to an electric fan or other electric propulsion unit would be useful. Summary of the Invention

[0005] Aspects and advantages of the invention will be set forth in part in the description which follows, or may be apparent from the description or understood by practice of the invention.

[0006] In one exemplary embodiment of this disclosure, a propulsion system for an aircraft is provided. The propulsion system includes an electric thruster and a gas turbine engine. The gas turbine engine includes a compressor section, a turbine section, and a rotating member rotatable together with at least a portion of the compressor section and at least a portion of the turbine. The propulsion system also includes a motor coupled to the rotating member of the gas turbine engine, the motor generating a voltage at a baseline voltage magnitude during operation of the gas turbine engine. The propulsion system also includes an electrical communication bus electrically connecting the motor to the electric thruster. The propulsion system further includes means for providing a differential voltage to the electric thruster equal to approximately twice the baseline voltage magnitude.

[0007] In another exemplary embodiment of this disclosure, a propulsion system for an aircraft is provided. The propulsion system includes an electric thruster, a first gas turbine engine including a rotating component, and a first electric motor coupled to the rotating component of the first gas turbine engine. The first electric motor is a center-tapped grounded AC generator. The propulsion system also includes a second gas turbine engine including a rotating component and a second electric motor coupled to the rotating component of the second gas turbine engine. The second electric motor is a center-tapped grounded AC generator. The propulsion system further includes an electrical communication bus electrically connecting the first and second electric motors to the electric thruster. The electrical communication bus includes at least one AC-to-DC converter for converting AC voltage from the first electric motor and AC voltage from the second electric motor into positive DC voltage and negative DC voltage for powering the electric thruster.

[0008] In yet another exemplary embodiment of this disclosure, a propulsion system for an aircraft is provided. The propulsion system includes an electric thruster, a first gas turbine engine including a rotating member, and a first electric motor coupled to the rotating member of the first gas turbine engine. The first electric motor is a DC generator configured to generate a positive DC voltage. The propulsion system also includes a second gas turbine engine including a rotating member, and a second electric motor coupled to the rotating member of the second gas turbine engine. The second electric motor is a DC generator configured to generate a negative DC voltage. The propulsion system also includes an electrical communication bus that electrically connects the first and second electric motors to the electric thruster to provide the electric thruster with a net differential voltage equal to approximately twice the amplitude of the positive DC voltage.

[0009] These and other features, aspects, and advantages of the invention will become more readily understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0010] The complete and open disclosure of the invention, including its best mode, is set forth in the specification with reference to the accompanying drawings, in which:

[0011] Figure 1 This is a top view of an aircraft according to various exemplary embodiments of the present disclosure.

[0012] Figure 2 for Figure 1 A port side view of an exemplary aircraft.

[0013] Figure 3 A schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of this disclosure.

[0014] Figure 4 A schematic cross-sectional view of an electric motor embedded in a gas turbine engine according to an exemplary embodiment of the present disclosure.

[0015] Figure 5 A schematic cross-sectional view of an electric motor embedded in a gas turbine engine according to another exemplary embodiment of the present disclosure.

[0016] Figure 6 A close-up cross-sectional view of a cable positioned within a cooling conduit according to an exemplary embodiment of the present disclosure.

[0017] Figure 7 A schematic cross-sectional view of an electric motor embedded in a gas turbine engine according to yet another exemplary embodiment of this disclosure.

[0018] Figure 8 A schematic cross-sectional view of an electric motor embedded in a gas turbine engine according to yet another exemplary embodiment of this disclosure.

[0019] Figure 9 A close-up cross-sectional view of a cable according to an exemplary embodiment of the present disclosure.

[0020] Figure 10 This is a schematic diagram of a propulsion system according to an exemplary embodiment of the present disclosure.

[0021] Figure 11 This is a schematic diagram of an electric motor according to an exemplary embodiment of the present disclosure.

[0022] Figure 12 This is a schematic diagram of an electric motor according to another exemplary embodiment of the present disclosure.

[0023] Figure 13 This is a schematic diagram of an electric motor according to yet another exemplary embodiment of the present disclosure.

[0024] Figure 14 This is a schematic diagram of an AC-to-DC voltage converter according to an exemplary embodiment of the present disclosure.

[0025] Figure 15 This is a schematic diagram of a propulsion system according to another exemplary embodiment of the present disclosure.

[0026] Figure 16 A schematic cross-sectional view of a gas turbine engine according to another exemplary embodiment of the present disclosure. Detailed Implementation

[0027] Referring now to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Detailed description uses numerical and alphabetic designations to denote features in the drawings. Similar or analogous designations in the drawings and specification have been used to denote similar or analogous parts of the invention. As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components. The terms "front" and "rear" refer to relative positions within a gas turbine engine, where "front" refers to a position closer to the engine inlet and "rear" refers to a position closer to the engine nozzle or exhaust port. The terms "upstream" and "downstream" refer to relative directions of fluid flow in a fluid passage. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows.

[0028] Referring now to the accompanying drawings, the same numbers throughout the drawings represent the same elements. Figure 1 A top view of an exemplary aircraft 10 that can be incorporated into various embodiments of the present invention is provided. Figure 2 Provide such as Figure 1 The image shows a port side view of aircraft 10. Figure 1 and 2 As shown in the diagram, the aircraft 10 is defined by a longitudinal centerline 14 extending through it, a vertical direction V, a lateral direction L, a front end 16, and a rear end 18. Furthermore, the aircraft 10 is defined by a centerline 15 extending between the front end 16 and the rear end 18. As used herein, "centerline" refers to the midpoint line extending along the length of the aircraft 10, without considering accessories of the aircraft 10 (such as the wing 20 and stabilization devices discussed below).

[0029] Furthermore, the aircraft 10 includes a fuselage 12 extending longitudinally from the front end 16 of the aircraft 10 toward the rear end 18 of the aircraft 10, and a pair of wings 20. As used herein, the term "fuselage" generally includes all the body of the aircraft 10, such as the tail of the aircraft 10. The first of the wings 20 extends laterally outward from the port side 22 of the fuselage 12 relative to the longitudinal centerline 14, and the second of the wings 20 extends laterally outward from the right chord 24 of the fuselage 12 relative to the longitudinal centerline 14. Each wing 20 for the exemplary embodiments depicted includes one or more leading-edge flaps 26 and one or more trailing-edge flaps 28. The aircraft 10 also includes a vertical stabilizing device 30 having rudder flaps 32 for yaw control, and a pair of horizontal stabilizing devices 34 each having elevator flaps 36 for pitch control. The fuselage 12 also includes an outer surface or skin 38. However, it should be recognized that in other exemplary embodiments of this disclosure, the aircraft 10 may, additionally or alternatively, include any other suitable construction of stabilizing devices that may or may not extend directly in the vertical direction V or the horizontal / lateral direction L.

[0030] Figure 1 and 2 The exemplary aircraft 10 includes a propulsion system 100, referred to herein as "system 100". The exemplary system 100 includes one or more aircraft engines and one or more electric propulsion engines. For example, the depicted embodiment includes a plurality of aircraft engines, each configured to be mounted to the aircraft 10 (such as to one of a pair of wings 20), and an electric propulsion engine. More specifically, for the depicted embodiment, the aircraft engines are configured as gas turbine engines, or more precisely, as turbofan jet engines 102, 104, which are attached to and suspended below the wings 20 in an underwing configuration. Additionally, the electric propulsion engine is configured to be mounted at the rear end of the aircraft 10, and therefore the depicted electric propulsion engine may be referred to as the "rear engine". Furthermore, the depicted electric propulsion engine is configured to take in and consume air forming a boundary layer above the fuselage 12 of the aircraft 10. Therefore, the depicted exemplary rear engine may be referred to as a boundary layer intake (BLI) fan 106. The BLI fan 106 is mounted to the aircraft 10 at a location aft of the wing 20 and / or the jet engines 102, 104. Specifically, in the depicted embodiment, the BLI fan 106 is fixedly connected to the fuselage 12 at the rear end 18, such that the BLI fan 106 is incorporated into or merged with the tail section at the rear end 18, and that the centerline 15 extends through it. However, it should be appreciated that in other embodiments, the electric propulsion engine can be constructed in any other suitable manner and need not necessarily be constructed as a rear fan or a BLI fan.

[0031] Still refer to Figure 1 and Figure 2In some embodiments, the propulsion system further includes one or more generators 108 operable with the jet engines 102, 104. For example, one or both of the jet engines 102, 104 may be configured to provide mechanical power to the generator 108 from a rotating shaft (such as an LP shaft or HP shaft). Although schematically depicted external to the respective jet engines 102, 104, in some embodiments, the generator 108 may be located within the respective jet engines 102, 104. Additionally, the generator 108 may be configured to convert mechanical power into electrical power. For the depicted embodiment, the propulsion system 100 includes a generator 108 for each jet engine 102, 104, and also includes a power regulator 109 and an energy storage device 110. The generator 108 may send electricity to the power regulator 109, which may convert the electrical energy into an appropriate form and store the energy in the energy storage device 110 or send the electrical energy to the BLI fan 106. In the depicted embodiment, generator 108, power regulator 109, energy storage device 110, and BLI fan 106 are all connected to electrical communication bus 111, such that generator 108 is electrically connected to BLI fan 106 and / or energy storage device 110, and that generator 108 can supply power to one or both of energy storage device 110 and BLI fan 106. Therefore, in such an embodiment, propulsion system 100 may be referred to as a pneumatic-electric propulsion system.

[0032] However, it should be recognized that, Figure 1 and 2The aircraft 10 and propulsion system 100 depicted herein are provided by way of example only, and in other exemplary embodiments of this disclosure, any other suitable aircraft 10 may be provided having a propulsion system 100 constructed in any other suitable manner. For example, it should be appreciated that in various other embodiments, the BLI fan 106 may alternatively be positioned at any suitable location near the rear end 18 of the aircraft 10. Furthermore, in yet other embodiments, the electric propulsion engine may not be positioned at the rear end of the aircraft 10, and therefore may not be constructed as a "rear engine". For example, in other embodiments, the electric propulsion engine may be integrated into the fuselage of the aircraft 10, and therefore constructed as a "podded engine" or pod-mounted engine. Furthermore, in yet other embodiments, the electric propulsion engine may be integrated into the wing of the aircraft 10, and therefore may be constructed as a "blended wing engine". Furthermore, in other embodiments, the electric propulsion engine may not be a boundary layer take-off fan, and may instead be mounted as a free-flow jet fan at any suitable location on the aircraft 10. Furthermore, in other embodiments, the propulsion system 100 may not include, for example, a power regulator 109 and / or an energy storage device 110, and instead, one or more generators 108 may be directly connected to the BLI fan 106.

[0033] Now for reference Figure 3 This document provides a schematic cross-sectional view of a propulsion engine according to exemplary embodiments of the present disclosure. In some exemplary embodiments, the propulsion engine may be configured as a high-bypass turbofan jet engine 200, referred to herein as "turbofan 200". Notably, in at least some embodiments, jet engines 102, 104 may also be configured as high-bypass turbofan jet engines. In various embodiments, turbofan 200 may represent jet engines 102, 104. However, alternatively, in other embodiments, turbofan 200 may be incorporated into any other suitable aircraft 10 or propulsion system 100.

[0034] like Figure 3 As shown, the turbofan 200 defines an axial direction A (extending parallel to the longitudinal centerline 201 provided for reference), a radial direction R, and a circumferential direction C (extending around the axial direction A). Figure 3 (Not shown in the image). Generally, the turbofan 200 includes a fan section 202 and a core turbine engine 204 located downstream of the fan section 202.

[0035] The illustrated exemplary core turbine engine 204 generally includes a substantially tubular housing 206 defining an annular inlet 208. The housing 206 surrounds, in a flow-through relationship, a compressor section including a supercharger or low-pressure (LP) compressor 210 and a high-pressure (HP) compressor 212; a combustion section 214; a turbine section including a high-pressure (HP) turbine 216 and a low-pressure (LP) turbine 218; and an exhaust nozzle section 220. The compressor section, combustion section 214, and turbine section together define a core airflow path 221 extending from the annular inlet 208 through the LP compressor 210, HP compressor 212, combustion section 214, HP turbine section 216, LP turbine section 218, and exhaust nozzle section 220. A high-pressure (HP) shaft or rotor 222 drivesably connects the HP turbine 216 to the HP compressor 212. A low-pressure (LP) shaft or rotor 224 drivesly connects the LP turbine 218 to the LP compressor 210.

[0036] In the depicted embodiment, fan section 202 includes a variable-pitch fan 226 having a plurality of fan blades 228 spaced apart and coupled to disk 230. As depicted, the fan blades 228 extend generally radially outward from disk 230. Each fan blade 228 is rotatable about disk 230 about a pitch axis P, and is operatively coupled to a suitable actuator 232 configured to collectively change the pitch of the fan blade 40. The fan blades 228, disk 230, and actuator 232 are rotatable together about a longitudinal axis 12 via an LP shaft 224 spanning a power gearbox 234. The power gearbox 234 includes a plurality of gears for progressively reducing the rotational speed of the LP shaft 224 to a more efficient fan speed.

[0037] See also Figure 3 In an exemplary embodiment, disk 230 is covered by a rotatable front hub 236, which is aerodynamically profiled to facilitate airflow through a plurality of fan blades 228. Additionally, an exemplary fan section 202 includes an annular fan housing or outer nacelle 238 that circumferentially surrounds at least a portion of the fan 226 and / or the core turbine engine 204. The nacelle 238 is supported relative to the core turbine engine 204 by a plurality of circumferentially spaced outlet guide vanes 240. A downstream section 242 of the nacelle 238 extends over the exterior of the core turbine engine 204 to define a bypass airflow path 244 between them.

[0038] Although not depicted, various rotating components of the turbofan engine 10 (e.g., LP shaft 224, HP shaft 222, fan 202) may be supported by one or more oil-lubricated bearings. The depicted turbofan engine 10 includes a lubrication system 245 for supplying lubricating oil to one or more of the oil-lubricated bearings. Furthermore, the lubrication system 245 may include one or more heat exchangers for transferring heat from the lubricating oil using, for example, bypass air, vent air, or fuel.

[0039] Additionally, the depicted exemplary turbofan 200 includes a motor 246 rotatable together with the fan 226. Specifically, in the depicted embodiment, the motor 246 is configured as a generator coaxially mounted to and rotatable together with the LP shaft 224 (in the depicted embodiment, the LP shaft 224 also passes through a power gearbox 234 to rotate the fan 226). As used herein, "coaxially" means axis alignment. However, it should be appreciated that in other embodiments, the axis of the motor 246 may be radially offset from the axis of the LP shaft 224 and may also be tilted relative to the axis of the LP shaft 224, such that the motor 246 can be positioned at any suitable location at least partially inside the core airflow path 221.

[0040] The motor 246 includes a rotor 248 and a stator 250. In some exemplary embodiments, the rotor 248 and stator 250 of the motor 246 are constructed in a manner substantially the same as the exemplary rotor and stator of the motor described below. It is worth noting that when the turbofan engine 200 is integrated into the above reference... Figure 1 and Figure 2 In the described propulsion system 100, the generator 108 can be coupled with... Figure 3 The motor 246 is constructed in basically the same way.

[0041] However, it should also be recognized that, Figure 3 The exemplary turbofan engine 200 depicted herein is provided by way of example only, and in other exemplary embodiments, the turbofan engine 200 may have any other suitable configuration. For example, in other exemplary embodiments, the turbofan engine 200 may be configured as a turboprop engine, a turbojet engine, a turbofan engine of a different configuration, or any other suitable gas turbine engine.

[0042] Now for reference Figure 4 The illustration depicts an electric motor 246 embedded within a gas turbine engine according to exemplary embodiments of the present disclosure. More specifically, in the illustrated embodiment, the electric motor 246 is embedded within the turbine section of the gas turbine engine, and even more specifically, attached to the LP shaft 224 of the gas turbine engine. Furthermore, the electric motor 246 is at least partially positioned within or behind the turbine section in the axial direction A. In some exemplary embodiments, Figure 4The electric motor 246 and gas turbine engine described in the text can be referenced above. Figure 3 The exemplary electric motor 246 and turbofan engine 200 described are constructed in essentially the same manner. Therefore, the same or similar numbers may refer to the same or similar parts.

[0043] As depicted, the motor 246 generally comprises a rotor 248 and a stator 250. The rotor 248 is directly attached to the LP shaft 224 via a plurality of rotor connecting members 252, such that the rotor 248 is rotatable together with the LP shaft 224. In contrast, the stator 250 is attached to a structural support member 256 of the turbine section via one or more stator connecting members 254. In at least some exemplary embodiments, the motor 246 may be a generator, such that the rotor 248 and the rotor connecting members 252 are driven by the LP shaft 224. In such an embodiment, the rotation of the rotor 248 relative to the stator 250 can generate electricity, which can be transmitted via an electrical communication bus 258, discussed in more detail below.

[0044] However, it should be recognized that in other exemplary embodiments, the motor 246 may be modified to have any other suitable configuration. For example, in other embodiments, the motor 246 may include a rotor 248 located radially inside the stator 250 (e.g., as an in-running electric machine).

[0045] Still referencing Figure 4 The exemplary motor 246, structural support member 256 may be configured as part of rear frame assembly 257 and extends from rear frame strut 258 of rear frame assembly 257 of gas turbine engine. Rear strut 258 extends through core airflow path 221 of gas turbine engine and is configured to provide structural support for gas turbine engine. Structural support member 256 also extends forward to support rear engine bearing 262, which rotatably supports the rear end of LP shaft 224.

[0046] The stator connection member 254 may be an annular / cylindrical member extending from the structural support member 256 of the gas turbine engine. In the depicted embodiment, the stator connection member 254 supports the rotation of a plurality of rotor connection members 252 by one or more bearings. More specifically, the front motor bearing 264 is positioned in front of the motor 246 and radially between the rotor connection member 252 and the stator connection member 254. Similarly, the rear motor bearing 266 is positioned behind the motor 246 and radially between the rotor connection member 252 and the stator connection member 254. Particularly in the depicted embodiment, the front motor bearing 264 is constructed as a roller element bearing, and the rear motor bearing 266 comprises a pair of bearings constructed as a roller element bearing and a ball bearing. However, it should be appreciated that the front motor bearing 264 and the rear motor bearing 266 may have any other suitable configuration in other embodiments, and this disclosure is not intended to limit to the specific configuration depicted, unless such limitations are imposed by the claims.

[0047] The gas turbine engine also includes a cavity wall 268 that surrounds at least a portion of the motor 246. More specifically, in the depicted embodiment, the cavity wall 268 substantially completely surrounds the motor 246, extending from a position in front of the motor 246 (attached to the structural support member 256 via stator connection member 254) to a position behind the motor 246. The cavity wall 268 at least partially defines a motor reservoir 270 that substantially completely surrounds the motor 246. More specifically, the motor reservoir 270 extends continuously from the position in front of the motor 246 to the position behind the motor 246. Certain components of the gas turbine engine include openings 272 to allow this continuous extension of the motor reservoir 270.

[0048] It is noteworthy that, in the depicted embodiment, the motor reservoir 270 also surrounds the rear engine bearing 262 of the gas turbine engine. The gas turbine engine includes a sealing arm 274 attached to the structural support member 256 and extending anterior to the rear engine bearing 262 to form a seal with the LP shaft 224, and is also included within the motor reservoir 270. It is noteworthy that the sealing assembly 276 is configured as part of the sealing arm 274 and / or the LP shaft 224 to provide and maintain the seal of the motor reservoir 270. Also depicted, the gas turbine engine includes a plurality of sealing assemblies 276 adjacent to the front motor bearing 264 and the rear motor bearing 266 to maintain the seal of the motor 246, i.e., to prevent lubricating oil from reaching the rotor 248 and stator 250 of the motor 246.

[0049] Furthermore, the depicted gas turbine engine includes an electro-lubrication system 278, which is in fluid communication with an electro-lubrication reservoir 270 for supplying hot fluid to the reservoir 270. In the depicted embodiment, the electro-lubrication system 278 may operate independently of the gas turbine engine lubrication system, as described above. Figure 3 The lubrication system 245 is described.

[0050] Specifically, for the depicted embodiment, the motor lubrication system 278 includes a supply pump 280 connected to a supply line 282 extending into the motor reservoir 270. The supply line 282 extends radially in the direction R from a location outside the core airflow path 221, passes through the rear engine strut 258 (and through the core airflow path 221), passes through the cavity wall 268, and reaches the motor reservoir 270. The hot fluid may be lubricating oil or other suitable lubricant for lubricating the front motor bearing 264, the rear motor bearing 266, and the rear engine bearing 262. Notably, the hot fluid is also configured to receive heat from the multiple bearings and the motor reservoir 270. The heated hot fluid is removed from the motor reservoir 270 via a removal line 284 of the lubrication system 278, which extends from the motor reservoir 270, through the core airflow path 221, and reaches the removal pump 286. However, it should be recognized that although the purging line 284 extends through the core airflow path 221 at a location outside the pillar 260 in the depicted embodiment, in other embodiments, the purging line 284 may instead extend through the pillar 260 alongside the supply line 282.

[0051] It is worth noting that, in the depicted embodiment, the motor lubrication system 278, including the supply pump 280 and the purging pump 286, may be at least partially powered by the motor 246. Additionally, although not depicted, the motor lubrication system 278 may further include one or more heat exchangers for reducing the temperature of the purged hot fluid before it is supplied back to the motor reservoir 270 via the supply line 282.

[0052] It is worth noting that, in such embodiments, the lubrication system 278 may be further configured as part of the cooling system of the gas turbine engine for reducing the temperature of the motor 246. For example, the inventors of this disclosure have found that, for at least some embodiments, supplying lubricating oil to the lubricating oil supply line 282 at a temperature below about 275℉ (such as below about 250℉) allows the lubricating oil to receive the heat required to maintain the motor 246 within the desired temperature operating range during operation of the gas turbine engine. It should be understood that approximate terms such as "about" or "approximately" as used herein refer to terms within a 10% margin of error. Furthermore, it should be understood that, in other embodiments, the lubricating oil supplied to the supply line 282 may have any other suitable temperature.

[0053] To further maintain the temperature of the motor 246, the cooling system of the depicted exemplary gas turbine engine also includes a buffer cavity 288 surrounding at least a portion of the motor 246 to insulate the motor 246. More specifically, in the depicted embodiment, the cavity wall 268 further defines the buffer cavity 288 at least partially, wherein the buffer cavity 288 is positioned opposite the cavity wall 268 of the motor reservoir 270. Additionally, as Figure 4 As depicted, the extension member 290 is attached to or integrally formed with the structural support member 256 and extends at least partially around the cavity wall 268. Specifically, in the depicted embodiment, the structural support member 256 and the extension member 290 together extend completely around the cavity wall 268. The structural support member 256 and the extension member 290 together define a buffer cavity 288, which, in the depicted embodiment, extends continuously in the axial direction A from a position in front of the motor 246 to a position behind the motor 246. The buffer cavity 288 can act as an insulator from the relatively hot operating temperature within the core airflow path 221 extending through the turbine section of the gas turbine engine.

[0054] Furthermore, in the depicted embodiment, the gas turbine engine also includes a cooling duct 292. The cooling duct 292 is in airflow communication with a buffer chamber 288 for providing a cooling airflow to the buffer chamber 288. For example, in the depicted embodiment, the cooling duct 292 defines an outlet 293 extending through a structural support member 256 to provide a cooling airflow from the cooling duct 292 through the structural support member 256 and into the buffer chamber 288. The cooling duct 292 may also be in communication with a relatively cold air source airflow for providing the cooling airflow. In some exemplary embodiments, the cold air source may be a compressor section of the gas turbine engine (from which the cooling airflow may be diverted) or a fan of the gas turbine engine (from which the cooling airflow may be diverted). Notably, in the depicted embodiment, the gas turbine engine also includes an exhaust duct 291. The exhaust duct 291 is in airflow communication with the buffer chamber 288 and is configured to discharge the cooling airflow to a core airflow path 221, a bypass path (e.g., Figure 3 (The passageway 244), or the environmental location. Such a configuration allows a continuous airflow of cooling air through the buffer chamber 288.

[0055] As discussed, the motor lubrication system 278, cooling conduit 292, and buffer chamber 288 are each configured as part of a cooling system to maintain at least some components of the motor 246 within a desired temperature range. For example, in embodiments where the motor 246 is configured as a generator, the generator may be configured as a permanent magnet generator comprising a plurality of permanent magnets 294 (depicted in dashed lines). In these embodiments, the rotor 248 may include a plurality of permanent magnets 294, and the stator 250 may include coils of one or more conductive wires (not shown). However, it should be appreciated that in other embodiments, the motor 246 may alternatively be configured as an electromagnetic generator, comprising a plurality of electromagnets and active circuitry, as an induction motor, a switched reluctance motor, a synchronous AC motor, or any other suitable generator or motor.

[0056] As will be appreciated, each of the plurality of permanent magnets 294 (when included) defines a Curie temperature limit, which may be less than the temperature within the core airflow path 221 extending through the turbine section of the gas turbine engine. The gas turbine engine's cooling system maintains the temperature of the motor 246 (and more specifically each permanent magnet 294) below the Curie temperature limit for the plurality of permanent magnets 294. Furthermore, the cooling system may maintain the temperature of the motor 246 below a predetermined limit of the Curie temperature limit to, for example, increase the lifespan of the motor 246. For example, in some exemplary embodiments, the gas turbine engine's cooling system may maintain the temperature of the motor 246 below a limit of at least about 50 degrees Fahrenheit (℉) of the Curie temperature limit, such as below a limit of at least about 75℉ or 100℉. Maintaining the temperature of the motor 246 below such a limit of the Curie temperature limit further prevents any permanent magnet of the motor 246 from undergoing irreversible (or permanent) demagnetization, which could negatively impact the lifespan of the motor 246.

[0057] However, it should be recognized that, Figure 4 The exemplary cooling system depicted in the embodiments is provided by way of example only. In other embodiments, the gas turbine engine may include any other suitable cooling system. For example, in other embodiments, the motor lubrication system 278 may have any other suitable configuration. For example, the motor lubrication system 278 may be operable in conjunction with the engine lubrication system 278. Additionally, in some embodiments, the cavity wall 268 may have any other suitable features for maintaining the temperature of the motor 246 within the desired operating range. For example, reference is now briefly made to... Figure 5 The diagram depicts a cross-sectional schematic of an electric motor 246 embedded within a gas turbine engine according to another exemplary embodiment of the present disclosure. Figure 5 The exemplary gas turbine engine depicted in the image can be coupled with... Figure 4The exemplary gas turbine engines depicted are constructed in essentially the same manner, and therefore the same or similar figures may refer to the same or similar parts. However, for Figure 5 In some embodiments, the cavity wall 268, which at least partially defines the buffer cavity 288, also includes an insulating layer 296 to further isolate the motor 246 from the relatively hot operating temperature within the core airflow path 221 extending through the turbine section of the gas turbine engine. The insulating layer 296 may be any suitable insulator used to reduce the thermal conductivity of the cavity wall 268 surrounding the motor 246. Additionally, although not depicted, in some embodiments, a portion of the structural support member 256 and the extension member 290 (which also at least partially defines the buffer cavity 288) may also include an insulating layer.

[0058] Refer again Figure 4 In this embodiment, as briefly described above, during operation of the gas turbine engine, the LP shaft 224 rotates the rotor 248 of the motor 246, thereby allowing the motor 246 to function as a generator to produce electricity. Additionally, the motor 246 is electrically connected to an electrical communication bus 258. The electrical communication bus 258 is electrically connected to the motor 246 at a location radially inward of the core airflow path 221. The electrical communication bus 258 includes a first junction box 298 mounted to a stator connection component 254. The first junction box 298 receives wires 300 from the motor 246 (or, in the depicted embodiment, from the stator 250 of the motor 246) and connects the wires 300 to an intermediate section 302 of the electrical communication bus 258. The intermediate section 302 extends within the gas turbine engine's cowling through the core airflow path 221 to a second junction box 304 located radially outward of the core airflow path 221. The second junction box 304 connects the intermediate section 302 of the electrical communication bus 258 to the output line 306 of the electrical communication bus 258 for connection to one or more systems of the gas turbine engine and / or the aircraft on which the gas turbine engine is mounted. As briefly mentioned above, the motor lubrication system 278 may be electrically connected to the output line 306 of the electrical communication bus 258 for supplying power to the motor lubrication system 278.

[0059] like Figure 4 As indicated and depicted, at least a portion of the electrical communication bus 258 extends through the core airflow path 221. More specifically, for the depicted embodiment, the intermediate section 302 of the electrical communication bus 258 is located in the combustion section of the gas turbine engine (such as...). Figure 3 The intermediate section 302 extends through the core airflow path 221 at a location downstream of the combustion section 214 of the exemplary turbofan engine 200. Specifically, the intermediate section 302 extends through / is located within the rear strut 258, which is situated in the portion of the core airflow path 221 immediately downstream of the HP turbine 216.

[0060] Furthermore, as schematically depicted, the illustrated exemplary intermediate segment 302 is a cooling portion of the electrical communication bus 258, including a cable 308 (i.e., an electrical conductor) located within / extending through a conduit containing cooling fluid. Specifically, reference will now also be made to... Figure 6 A close-up view of a portion of intermediate section 302 is provided, which is configured to extend through the core airflow path 221 of the gas turbine engine. As depicted, intermediate section 302 of the electrical communication bus 258 includes a cable 308 positioned within and extending coaxially with supply line 282, such that during operation, cable 308 is wrapped with a relatively cool flow of hot fluid (indicated by arrow 310) to be supplied to, for example, motor reservoir 270. Thus, supply line 282 is considered an embodiment depicted as part of motor lubrication system 278 and intermediate section 302 of electrical communication bus 258. During operation, the hot fluid wrapping the cable 308 within intermediate section 302 of electrical communication bus 258 protects the cable 308 from the relatively high temperatures within the core airflow path 221, maintaining the temperature of the cable 308 within the desired operating range. However, it should be recognized that in other embodiments, the intermediate section 302 of the electrical communication bus 258 may instead include a cable 308 located within and extending coaxially with the clearing conduit 284 (which may also extend through the post 260 in some embodiments).

[0061] It is worth noting that cable 308 can be any suitable cable 308, and for the depicted embodiment, includes an electrical insulation layer 312 surrounding the conductive core portion 314. The electrical insulation layer 312 can include any suitable electrical insulator capable of being exposed to relatively high temperatures and also capable of isolating a relatively large amount of electricity that can be transmitted through the conductive core portion 314 of cable 308 (see discussion below). Additionally, although not depicted, cable 308 may also include a barrier layer surrounding the electrical insulation layer 312 and the conductive core portion 314 to prevent lubricating oil from contacting the insulation layer 312 and the conductive core portion 314. Furthermore, in some embodiments, cable 308 can be configured as described below. Figure 9 The cable 308 described is constructed in essentially the same manner.

[0062] As will be discussed in more detail below, the intermediate section 302 of the electrical communication bus 258 is configured to transmit a relatively high level of electrical power. Therefore, during operation, due to the transmission of the relatively high power level, the intermediate section 302 of the electrical communication bus 258 may experience relatively significant Joule heating or resistance heating. Despite experiencing resistance heating and exposure to the core airflow path 221, coaxially positioning the cable 308 of the intermediate section 302 with the lubricating oil supply line 282 helps maintain the temperature of the cable 308 within the desired operating temperature range.

[0063] However, it should be recognized that in other exemplary embodiments, the electrical communication bus 258 may have any other suitable configuration for transmitting power from the motor 246 located radially inside the core airflow path 221 to a location radially outside the core airflow path 221. For example, briefly refer now to Figure 7 The diagram depicts a cross-sectional schematic of an electric motor 246 embedded in a gas turbine engine according to yet another exemplary embodiment of the present disclosure. Figure 7 The exemplary gas turbine engine depicted in the image can be coupled with... Figure 4 The exemplary gas turbine engines depicted are constructed in essentially the same manner, and therefore the same or similar figures may refer to the same or similar parts.

[0064] However, for Figure 7 In some embodiments, the electrical communication bus 258 is modified to be a superconducting or superconducting electrical communication bus 258. Therefore, for Figure 7 In some embodiments, the intermediate section 302 of the electrical communication bus 258 may not have a supply line 282 for the motor lubrication system 278. Instead, the exemplary electrical communication bus 258 includes a separate cooled conduit 316 within which the cable 308 is positioned and extends. The electrical communication bus 258 includes a refrigerant system 318 for providing cold refrigerant within the cooled conduit 316 to maintain the temperature of the cable 308 extending through it at a relatively low temperature. For example, in some embodiments, the refrigerant system may maintain the temperature of the cable 308 at or below the critical temperature of the material forming the cable 308, or at least 1°F lower than the critical temperature of the material forming the cable 308.

[0065] Additionally, the cold refrigerant extends to the first junction box 298, where the refrigerant is separated from the wires as it returns through the return line 320 (partially depicted). For the depicted embodiment, the electrical communication bus 258 may also include components for operating the refrigerant system 318 in the refrigeration cycle, such as a pump, condenser, and expansion valve (not depicted). Notably, in at least some embodiments, a portion of the intermediate section 302 extending through the core airflow path 221 may serve as an evaporator for the refrigerant cycle.

[0066] Although, in the depicted embodiment, the gas turbine engine includes a separate motor lubrication system 278 and a refrigerant system 318, in other embodiments, the refrigerant utilized by the refrigerant system 318 via the electrical communication bus 258 may additionally serve as the refrigerant for various bearings within the motor 246 (and, in the depicted embodiment, for the rear engine bearing 262), such that the refrigerant system 318 and the motor lubrication system 278 can be constructed together as a single system.

[0067] Now for reference Figure 8 The diagram depicts a cross-sectional schematic of an electric motor 246 embedded in a gas turbine engine according to yet another exemplary embodiment of the present disclosure. Figure 8 The exemplary gas turbine engine depicted in the image can be coupled with... Figure 4 The exemplary gas turbine engines depicted are constructed in essentially the same manner, and therefore the same or similar figures may refer to the same or similar parts. However, for Figure 8 In one embodiment, the intermediate segment 302 of the electrical communication bus 258 is not configured to be coaxial with the cooling fluid conduit (e.g., supply line 282). Instead, for Figure 8 In one embodiment, the middle section 302 of the electrical communication bus 258 is formed by a cable 308, which is designed to withstand the relatively high temperature of the core airflow path 221 of the gas turbine engine at a location downstream of the combustion section of the gas turbine engine.

[0068] More specifically, as in the embodiments described above, the electrical communication bus 258 includes a first junction box 298, a second junction box 304, and a cable 308 extending between them (i.e., the intermediate segment 302). Although the cable 308 is depicted as a single cable, in some embodiments, the cable may include multiple cables. Brief reference will now also be made to... Figure 9 A close-up schematic diagram of cable 308 is provided. Cable 308 is formed of a material that can transmit relatively high amounts of electrical power and is exposed to relatively high temperatures within the core airflow path 221 without oxidation.

[0069] For example, in some embodiments, cable 308 may be composed of at least one solid nickel core. Alternatively, as in the depicted embodiment, cable 308 may be composed of at least one high-conductivity core volume (such as a low-resistivity / high-conductivity cable core 322) and at least one dielectric (electrically insulating) barrier volume (such as a high-resistivity cable sheath 324). The cable core 322 is positioned within the cable sheath 324 such that the cable sheath 324 surrounds the cable core 322. In some exemplary embodiments, the cable core 322 may be a copper core volume, and the cable sheath 324 may be a non-copper sheath volume. The cable sheath 324 may be created by one or more packaging processes, such as impregnation, co-extrusion, electroplating, spraying, coating, forging, roll forming, welding, or combinations thereof. The depicted cable 308 also includes an oxide barrier volume 323 positioned between the cable core 322 and the cable sheath 324. It is worth noting that cable 308 may be constructed as a braided, transposed and crimped wire harness, transposed bundle of one or more transposed wire harnesses, or any other suitable cable construction for transmitting alternating current ("AC") power in a manner that reduces AC coupling losses.

[0070] Additionally, in the depicted embodiments, the cable core 322 and cable sheath 324 of cable 308 are covered and enclosed within a high-temperature electrical insulation material 326. For example, in some embodiments, the high-temperature electrical insulation material 326 may be a sprayed layered barrier coating (ceramic), at least one partially overlapping tape layer (mica, glass fiber, ceramic fiber, and / or polymer film), an external armor barrier (braided, metallic, and / or non-metallic), or a combination thereof. As discussed below, the high-temperature electrical insulation material 326 is suitable for cable insulation that will carry a relatively large amount of electricity at relatively high temperatures. Furthermore, in the depicted embodiments, cable 308 includes at least one external armor volume 325 as an abrasion barrier, which in some embodiments may be the same as the insulation material 326.

[0071] As also depicted, the motor lubrication system 278 (configured as part of the overall motor cooling system) is configured to supply hot fluid directly to the second junction box 304 via the connecting line 328 for active cooling of the second junction box 304. Additionally, the hot fluid supply line 282 of the motor lubrication system 278 extends to the first junction box 298 and supplies hot fluid directly to the first junction box 298 for active cooling of the first junction box 298. Notably, in the depicted embodiment, the first junction box 298 includes a hot fluid outlet 330 for spraying the supplied hot fluid flow into the motor reservoir 270.

[0072] By actively cooling the first junction box 298 and the second junction box 304, the intermediate section 302, including the cable 308, can be allowed to operate at relatively high temperatures (such as temperatures resulting from exposure to the core airflow path 221, as well as Joule heating or resistance heating) during operation of the motor 246. The temperature of the cable 308 with this configuration can be reduced at the first junction box 298 and the second junction box 304, allowing the cable 308 to be electrically connected to other wires (e.g., outlet line 306 and wire 300) that may not be configured to operate at the relatively high temperatures at which the cable 308 in the intermediate section 302 can operate.

[0073] Furthermore, as also schematically depicted, further beneficial cooling can be achieved by equipping the second junction box 304 with an embedded auxiliary fluid flow loop 331 that is in thermal communication with the fluid conversion connection line 328. The auxiliary fluid within the auxiliary fluid flow loop 331 may be the same fluid supplied by the fluid supply line 282, or alternatively, a different heat transfer fluid. Furthermore, although not depicted, the auxiliary fluid itself may be in subsequent thermal communication with a heat dissipation medium such as aircraft engine fuel, propeller fan air, or motor electronics coolant.

[0074] During operation of a gas turbine engine including an electric motor 246 according to exemplary embodiments of the present disclosure, the electric motor 246 may be configured to generate a relatively large amount of alternating current. For example, in some embodiments, the electric motor 246 may be configured to generate and deliver 500 (500) volts ("V") or higher electrical power through the electrical connectivity bus 258. For example, in some embodiments, the electric motor 246 may be configured to generate and deliver 600 (600) V or higher electrical power through the electrical connectivity bus 258. Such a configuration can be achieved by the disclosed cooling system for maintaining the temperature of the electric motor 246 within a specific operating temperature range, and / or by designing the intermediate section 302 of the electrical connectivity bus 258 in a manner that allows it to be exposed to relatively high temperatures within the core airflow path 221 downstream of the combustion section of the gas turbine engine.

[0075] Additionally, now refer to Figure 10 A schematic diagram of an exemplary propulsion system 100 is provided. It will be appreciated that... Figure 10 (as well as Figures 11 to 15The symbols depicted herein may have the ordinary meanings applicable in the art. As schematically depicted and discussed above, propulsion system 100 includes at least one gas turbine engine (configured as a first engine 102 in the depicted embodiment) and a first motor 108A coupled to an electrical communication bus 258. The first engine 102 and the first motor 108A are configured to generate a baseline voltage level during operation. Propulsion system 100 also includes an electric thruster, which in some embodiments may be the depicted exemplary BLI fan 106 (BLI fan 106 includes a motor 350 that powers fan 352). Furthermore, the depicted exemplary propulsion system 100 includes means for providing a differential voltage to the electric thruster, the differential voltage being approximately twice the amplitude of the baseline voltage generated by the first motor 108A.

[0076] More specifically, for the depicted embodiment, the devices for providing a differential voltage to the electric thruster that is approximately twice the baseline voltage amplitude include a second gas turbine engine and a second motor 108B, which are combined with an electrical communication bus 258. More specifically, the devices for providing a differential voltage to the electric thruster that is approximately twice the baseline voltage amplitude include a second engine 104 and a second motor 108B, which are combined with an electrical communication bus 258. The first engine 102 and the second engine 104, as well as the first motor 108A and the second motor 108B, can be connected to... Figure 1 and Figure 2 It is constructed in the same manner as depicted above. Furthermore, each of the first engine 102 and the second engine 104 and the corresponding motor 108 can be constructed in the same manner as described above. Figures 4 to 8 One or more of the gas turbine engines described are constructed in substantially the same manner as the embedded motor 246.

[0077] Generally, in the depicted embodiment, the first motor 108A and the second motor 108B are configured to generate an alternating current ("AC") voltage at a baseline voltage level. An electrical connection bus 258 is configured to convert the AC voltage into a positive direct current ("DC") voltage and a negative DC voltage, each having a substantially the same amplitude as the baseline voltage level but with different polarities. The electrical connection bus 258 then converts the two DC voltages of equal amplitude (and opposite polarities) back into an AC voltage with a net difference of approximately twice the amplitude of the baseline voltage level, and supplies this differential AC voltage to the motor 350 of the electric thruster / BLI fan 106.

[0078] Specifically, for the exemplary embodiments depicted, the first motor 108A may be an N-phase generator having a first terminal 354 and a second terminal 356 generating a first voltage at a baseline voltage level. The first voltage level may be an AC voltage Vac. Similarly, the second motor 108B may be an N-phase generator having a first terminal 354 and a second terminal 356 generating a second voltage also at a baseline voltage level. Therefore, the second voltage level may also be an AC voltage Vac. For example, in some embodiments, the first motor 108A and / or the second motor 108B may be configured as described below. Figures 11 to 13 One or more of the described motors 108 are constructed in essentially the same manner.

[0079] Furthermore, the electrical connectivity bus 258 includes at least one AC-to-DC converter. Specifically, for the depicted embodiment, the electrical connectivity bus 258 includes a first N-phase AC-to-DC converter 358 electrically connected to the first motor 108A and a second N-phase AC-to-DC converter 360 electrically connected to the second motor 108B. The first converter 358 and the second converter 360 together convert the voltage Vac generated by the first motor 108A and the second motor 108B into a positive DC voltage +Vdc and a separate negative DC voltage -Vdc. Notably, as schematically shown, each of the first converter 258 and the second converter 260 is chassis grounded. Furthermore, the first converter 258 includes a first module 358A configured to convert the voltage Vac from the first terminal 354 of the first motor 108A into a positive DC voltage +Vdc, and a second module 358B configured to convert the voltage Vac from the second terminal 356 of the first motor 108A into a negative DC voltage -Vdc. Similarly, the second converter 360 includes a first module 360A configured to convert the voltage Vac from the first terminal 354 of the second motor 108B into a positive DC voltage +Vdc, and a second module 360B configured to convert the voltage Vac from the second terminal 356 of the second motor 108B into a negative DC voltage -Vdc.

[0080] Furthermore, the electrical connection bus 258 includes a positive DC transmission line 362 and a negative DC transmission line 364. A separate N-phase DC-to-AC converter 366 then converts the positive and negative DC transmission lines 362 and 364 to AC voltage. Details of the exemplary converter 366 are provided in... Figure 10 The bubble 368 depicted is schematically shown and simplified, and is generally referred to as an H-bridge pulse width modulation voltage converter. The converter 366 is also electrically connected to the terminal 370 of the motor 350 of the BLI fan 106.

[0081] In at least some embodiments, the electric propulsion device may require (or expect) a net differential voltage greater than the baseline voltage level, which may be greater than the amplitude that can be safely transmitted on any transmission line of the electrical connectivity bus 258. Therefore, Figure 10 The schematic configuration shown in the diagram allows the electrical bus 258 to provide a differential AC voltage Vdiff to the motor 350, which is twice the magnitude of the first and second voltages Vac (i.e., Vdiff = (+Vac) - (-Vac) = 2 x |Vac|).

[0082] For example, now briefly refer to Figures 11 to 13 Various motors 108 are provided according to various exemplary embodiments of the present disclosure. In some embodiments, one or both of the first motor 108A and the second motor 108B can be coupled with... Figures 11 to 13 One or more of the exemplary motors 108 depicted are constructed in essentially the same manner. Additionally, in some exemplary embodiments, Figures 11 to 13 The motor 108 depicted may be an embedded motor (similar to the motor described above).

[0083] First refer to Figure 11 In an exemplary embodiment, generator 108 may be an N-phase generator having a first terminal 354 and a second terminal 356. It should be understood that, as used herein, the term "N-phase" is used to indicate the ability of the component to include any suitable number of phases. Therefore, although generator 108 may be a two-phase generator for the depicted embodiment, in other embodiments, generator 108 may be modified to be a single-phase generator, a three-phase generator, a four-phase generator, etc. Generator 108 generally includes a rotor 372 and a stator 374. Rotor 372 is rotatable by an engine (e.g., a first engine 102 or a second engine 104) via shaft 376. It will be appreciated that the voltage generated by generator 108 is a function of the rotational speed Ω of rotor 372, the radius 378 of rotor 372, the number of turns or windings 380 in stator 374, etc. Figure 11 The stator 374 of the motor 108 is center-tapped and grounded (i.e., the center of the turns 380 of the stator 374 is grounded to the chassis), allowing the motor 108 to provide both positive and negative voltages at voltage levels + / - Vac. However, it is worth noting that, to do this, assuming the number of turns 380 of the stator 374 has been effectively reduced by half, the rotor 372 may need to rotate at twice the speed Ω. Furthermore, as schematically depicted, a power gearbox 382 may be provided between the motor and the motor 108 to increase the speed of the rotor 372 relative to the motor. To support the increased speed Ω, the depicted exemplary rotor 372 includes an overband or support belt 384 to provide support. It is worth noting that when the motor 108 is... Figure 4When constructed in the same manner as the exemplary motor 246, the support belt 384 may be configured as part of the rotor support member 252. Additionally, it should be recognized that in some embodiments, the support belt 384 may be necessary and not include the power gearbox 382.

[0084] Now for reference Figure 12 The image depicts a motor 108 according to another exemplary embodiment. Figure 12 The exemplary motor 108 can be compared with the one mentioned above. Figure 11 The exemplary motor 108 described is constructed in essentially the same manner. For example, Figure 12 The motor 108 generally comprises a rotor 372 and a stator 374, wherein the rotor 372 is rotatable from the motor via a shaft 376. However, for Figure 12 In one embodiment, rotor 372 is instead constructed as a tandem rotor having a first rotor segment 386 and a second rotor segment 388 arranged along the axis of shaft 376. Note that although the first rotor segment 386 and the second rotor segment 388 are depicted as spaced apart and connected by a separate shaft 376, in some embodiments, the first rotor segment 386 and the second rotor segment 388 may instead be positioned adjacent to each other and directly attached to or connected to each other.

[0085] As schematically indicated, the magnetic pole timing of the first rotor section 386 lags behind the magnetic pole timing of the second rotor section 388. Specifically, for the depicted embodiment, the first rotor section 386 and the second rotor section 388 are out of phase by 180 degrees. Additionally, the stator 374 has... Figure 11 The stator 374 of the motor has twice the number of turns 380, but similarly grounded to the chassis at the center (i.e., a center-tapped grounded motor). Furthermore, for the depicted embodiment, the rotor 372, or more specifically, the first rotor section 386 and the second rotor section 388 of the rotor 372 each define a radius 378, which is... Figure 11 The radius of the exemplary rotor 372 is approximately half that of 378. Therefore, as will be appreciated, Figure 12 The rotor 372 of the exemplary motor 108 can be coupled with Figure 11 The rotor 372 of the exemplary first motor 108 depicted rotates at the same speed. However, it is worth noting that, due to Figure 12 The rotor radius of the motor is 372, which is 378. Figure 11 The rotor 372 of the first motor is approximately half the radius 378, so rotor 372 may not require overbelt (or support belt 384) to support rotor 372 during operation.

[0086] For the above reference Figure 11 and 12Each motor 108 described, due to its center-tapped grounded configuration, can have its first terminal 354 and second terminal 356 each provide an AC voltage ranging from positive Vac to negative Vac. Therefore, in its simplest form, the device used to provide a differential voltage to the electric thruster that is approximately twice the amplitude of the baseline voltage can be the motor 108, which is a center-tapped grounded motor.

[0087] In addition, it is still referenced now. Figure 13 This provides another exemplary embodiment of the present disclosure. Figure 13 A schematic diagram of a motor 108 according to another exemplary embodiment of the present disclosure is provided. Figure 13 The exemplary motor 108 can be compared with the one mentioned above. Figure 12 The exemplary motor 108 described is constructed in essentially the same manner. For example, Figure 13 The motor 108 generally includes a rotor 372 and a stator 374, wherein the rotor 372 is rotatable from the motor via a shaft 376. Furthermore, the rotor 372 is configured as a series rotor having a first rotor section 386 and a second rotor section 388. As schematically indicated, the pole timing of the first rotor section 386 also lags behind the pole timing of the second rotor section 388. The stator 374 includes components... Figure 12 The exemplary stator 374 has essentially the same number of turns 380. However, the stator 374 is not grounded at the center, but is separated at the center between a first stator section 390 located adjacent to the first rotor section 386 and a second stator section 392 located adjacent to the second rotor section 388. Furthermore, the first stator section 390 is grounded at the center tap, and the second stator section 392 is also grounded at the center tap. Therefore, the first stator section 390 includes a corresponding first set of terminals 354, 356, and the second stator section 392 includes a second set of terminals 354, 356. With the number of turns 380 reduced in each stator section 390, 392, in order to generate a... Figure 11 and 12 For an exemplary motor 108 with a similar voltage, the rotor 372 must rotate at a speed Ω. Figure 11 and 12 The exemplary rotor 372 of the exemplary motor 108 rotates at twice the speed of the exemplary motor 108. Similarly, as schematically depicted, a power gearbox 382 may be provided between the motor and motor 108 to increase the rotational speed Ω of the rotor 372 relative to the motor. Therefore, although... Figure 13 The radius 378 of the exemplary rotor 372 is relatively small, but as the given rotational speed Ω increases, the exemplary rotor 372 may need to include a belt overpass or support belt 384, such as... Figure 13 The diagram depicts a structure used for support. Figure 13 An example rotor 372.

[0088] It is worth noting that, Figure 13 The exemplary motor can be used as a single motor to generate the desired voltage for an electric propulsion device. Specifically, Figure 13 The first stator section 390 and the first terminals 354 and 356 of the motor can be configured as follows: Figure 10 The exemplary first motor 108A in the example has a first terminal 354 and a second terminal 356, and Figure 13 The second terminals 354, 356 of the second stator section 392 of the motor can be constructed as follows: Figure 10 The exemplary second motor 108B in the example has a first terminal 354 and a second terminal 356. Alternatively, Figure 13 The exemplary motor can be simply constructed as a two-phase motor, wherein the first set of terminals 354,356 is the first phase and the second set of terminals 354,356 is the second phase.

[0089] Furthermore, it should be recognized that in other exemplary embodiments, the motor can be designed in any suitable manner to perform as described herein. For example, in other embodiments, the rotor 372 may define any suitable radius 378 or length, the stator 374 may include any suitable number of turns 380, and the rotor 372 may rotate at any suitable speed Ω to generate the desired voltage.

[0090] Now for reference Figure 14 An electrical communication bus 258, including an N-phase AC-to-DC converter 394, is schematically depicted according to another exemplary embodiment of this disclosure. In at least some exemplary embodiments, Figure 14 The converter 394 of the exemplary electrical bus 258 can be effectively combined with the above reference. Figure 10 The first converter 358 and the second converter 360 are described.

[0091] More specifically, Figure 14 The exemplary AC-to-DC converter 394 is configured as a two-phase AC-to-DC converter. However, it will be appreciated that in other embodiments, the features of the depicted exemplary converter 394 can be extrapolated to accommodate any other suitable number of phases, such that the converter 394 can be used with one or more generators (such as generators with any suitable number of phases) having any suitable number of phases. Figure 10 The first motor 108A and the second motor 108B are used together.

[0092] For details, please refer to the following: Figure 14 An exemplary two-phase AC-to-DC converter 394 is electrically connected to a first phase 396 of a permanent magnet generator and also electrically connected to a second phase 398 of the permanent magnet generator, each including a first terminal 354 and a second terminal 356. In some exemplary embodiments, the first phase 396 of the permanent magnet generator may be a first generator (such as...) Figures 11 to 13(one or more of the motors 108A depicted), and the second phase 398 of the permanent magnet generator may be a second generator (such as...). Figures 11 to 13 (One or more of the motors 108 depicted). Additionally or alternatively, in other embodiments, the first phase 396 of the generator may be... Figure 13 The exemplary motor is generated by the first rotor section 386 and the first stator section 390, and the second phase 398 of the generator can be generated by... Figure 13 The second rotor section 388 and the second stator section 392 of the exemplary motor are generated.

[0093] Therefore, it should be recognized that devices for providing a differential voltage to the electric thruster that is approximately twice the baseline voltage amplitude may include a multiphase center-tapped AC generator combined with a multiphase AC-to-DC converter configured to convert the generated AC voltage into a positive DC voltage and a negative DC voltage. In such embodiments, the device may also include a DC-to-AC converter, depending on the type of electric motor equipped with the electric thruster.

[0094] It should also be recognized that, in other exemplary embodiments, the device for providing a differential voltage to the electric thruster that is approximately twice the amplitude of the baseline voltage may include two N-phase AC generators, each coupled to an N-phase AC-to-DC converter configured to convert the AC voltage from the respective generator into a combined positive DC voltage and a combined negative DC voltage. Similarly, in such embodiments, the device may also include a DC-to-AC converter, depending on the type of electric motor equipped with the electric thruster.

[0095] Furthermore, it should be recognized that in other embodiments, motor 108 may not be an AC generator, but may be replaced with a DC generator. For example, see now. Figure 15 A schematic diagram of a propulsion system 100 according to another exemplary embodiment is provided. As schematically depicted, the propulsion system 100 includes at least one gas turbine engine (configured as a first engine 102 in the depicted embodiment) and a first motor 108A coupled to an electrical communication bus 258. The first engine 102 and the first motor 108A are configured to generate a baseline voltage level during operation. The propulsion system 100 also includes an electric thruster, which in some embodiments may be the depicted exemplary BLI fan 106 (the BLI fan 106 includes a motor 350 that powers a fan 352). Furthermore, the depicted exemplary propulsion system 100 includes means for providing a differential voltage to the electric thruster, the differential voltage being approximately twice the amplitude of the baseline voltage generated by the first motor 108A.

[0096] More specifically, for the depicted embodiment, the devices for providing a differential voltage to the electric thruster that is approximately twice the baseline voltage amplitude include a second gas turbine engine and a second motor 108B, which are combined with an electrical communication bus 258. More specifically, the devices for providing a differential voltage to the electric thruster that is approximately twice the baseline voltage amplitude include a second engine 104 and a second motor 108B, which are combined with an electrical communication bus 258. The first engine 102 and the second engine 104, as well as the first motor 108A and the second motor 108B, are each configured as DC generators. The first motor 108A is configured to generate a positive DC voltage Vdc, and the second motor 108B is configured to generate a negative DC voltage -Vdc. The voltages Vdc and -Vdc from the first motor 108A and the second motor 108B are combined to provide a differential voltage Vdiff to the motor 350 of the electric propulsion device, which is approximately twice the amplitude of the baseline voltage generated by the first motor 108A (i.e., Vdiff = (+Vdc) - (-Vdc) = 2 x |Vdc|).

[0097] In addition, now refer to Figure 16 A schematic cross-sectional view of a gas turbine engine according to another exemplary embodiment of the present disclosure is provided. In some embodiments, Figure 16 The exemplary gas turbine engine depicted in the above reference can be used in conjunction with the above reference. Figure 3 The exemplary gas turbine engines described are constructed in substantially the same manner. Therefore, the same or similar numbers may refer to the same or similar parts. For example, as depicted, the gas turbine engine is constructed as a turbofan engine, which generally includes a fan 202 and a core turbine engine 204. The core turbine engine 204 includes an LP compressor 210 connected to an LP turbine 218 via an LP shaft 224, and an HP compressor 212 connected to an HP turbine 216 via an HP shaft 222. In the depicted embodiment, the turbofan engine 200 also includes an electric motor 246. The electric motor 246 may be constructed in substantially the same manner as one or more of the embodiments described above with reference to the preceding figures.

[0098] However, as schematically depicted and shown in dashed lines, motor 246 can be positioned in any other suitable location for the illustrated embodiment. For example, motor 246 can be motor 246A, mounted coaxially with LP shaft 224 in front of HP compressor 212 and substantially radially inward of LP compressor 210. Alternatively, motor 246 can be motor 246B, mounted coaxially with HP shaft 222, for example, in front of HP compressor 212. Alternatively, motor 246 can be motor 246C, mounted coaxially with LP shaft 224, at least partially behind HP turbine 216 and at least partially in front of LP turbine 218. Alternatively, motor 246 can be motor 246D, mounted coaxially with LP shaft 224 and HP shaft 222, such that motor 246D is a differential motor. Furthermore, in other embodiments, motor 246 can be mounted in any other suitable location.

[0099] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any apparatus or system, and performing any incorporated methods. The scope of the invention is defined by the claims and may include other examples that may occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that are not different from the written language of the claims, or if they include equivalent structural elements that are not substantially different from the written language of the claims.

Claims

1. A gas turbine engine defining radial and axial directions, the gas turbine engine comprising: Turbine section; A rotating component that is rotatable together with at least a portion of the turbine section; Lubrication components; An electric motor, which is at least partially connected to the rotating member on the inner side of the turbine section along the radial direction; A motor reservoir, fluidly connected to the lubrication assembly, for receiving lubricating fluid flow from the lubrication assembly; and A cooling system configured to keep the motor within a predetermined temperature range.

2. The gas turbine engine according to claim 1, wherein, The lubrication assembly is configured as part of the cooling system to cool the motor, thereby maintaining the motor within the predetermined temperature range.

3. The gas turbine engine according to claim 2, The lubrication assembly includes a lubricating oil supply line that provides lubricating fluid flow to the motor reservoir, and in, The lubrication assembly is configured to provide a flow of lubricating oil to the lubricating oil supply line at temperatures below 275°F.

4. The gas turbine engine according to claim 3, The lubrication assembly includes a heat exchanger that reduces the temperature of the lubricating oil flow supplied to the lubricating oil supply line.

5. The gas turbine engine according to claim 1, A sealing cavity assembly includes one or more fluid seals that at least partially define a sealing cavity and are configured to prevent lubricating fluid from the motor reservoir from entering the sealing cavity, wherein the motor is enclosed within the sealing cavity.

6. The gas turbine engine according to claim 5, in, The cooling system includes a buffer chamber surrounding at least a portion of the sealed cavity to insulate the motor.

7. The gas turbine engine according to claim 1, The motor described herein includes multiple permanent magnets, and in, The entire predetermined temperature range is at least 100°F lower than the Curie temperature limit of each of the plurality of permanent magnets.

8. The gas turbine engine according to claim 2, The turbine section partially defines the core airflow path of the gas turbine engine. The lubrication assembly includes a lubricating oil supply line that provides lubricating fluid flow to the motor reservoir, and The lubricating oil supply line passes through the core airflow path within the rear frame of the gas turbine engine.

9. A method for operating a gas turbine engine that defines a radial direction and an axial direction. The gas turbine includes a turbine section and an electric motor located at least partially inside the turbine section along the radial direction. The method includes: The motor is maintained within a predetermined temperature range by a cooling system.

10. The method according to claim 9, wherein, The maintenance also includes: The motor is cooled by a lubrication assembly, thereby maintaining the motor within the predetermined temperature range.

11. The method according to claim 10, wherein, The maintenance also includes: Lubricating fluid flow is provided to the lubricating oil supply line of the lubrication assembly at a temperature below 275°F.

12. The method according to claim 11, wherein, The maintenance also includes: The lubricating fluid is passed through a heat exchanger to reduce the temperature of the lubricating oil flow supplied to the lubricating oil supply line.

13. The method according to claim 9, The motor is disposed within a sealing assembly including one or more fluid seals, and in, At least a portion of the sealed cavity is provided with a buffer cavity to insulate the motor.

14. The method according to claim 9, The motor mentioned above includes multiple permanent magnets, and in, The entire predetermined temperature range is at least 100°F lower than the Curie temperature limit of each of the plurality of permanent magnets.

15. The method according to claim 9, The maintenance also includes providing a flow of lubricating fluid to the lubricating oil supply lines of the lubrication components. The turbine section partially defines the core airflow path of the gas turbine engine, and The lubricating oil supply line passes through the core airflow path within the rear frame of the gas turbine engine.

16. A gas turbine engine defining a radial direction and an axial direction, the gas turbine engine comprising: The hot section includes the turbine section and the exhaust section; A rotating component that is rotatable together with at least a portion of the turbine section; Lubrication components; An electric motor, which is at least partially connected to the rotating member along the radial direction inside the hot section; A motor reservoir, fluidly connected to the lubrication assembly, for receiving lubricating fluid flow from the lubrication assembly; and A cooling system configured to keep the motor within a predetermined temperature range.

17. The gas turbine engine according to claim 16, wherein, The lubrication assembly is configured as part of the cooling system to cool the motor, thereby maintaining the motor within the predetermined temperature range.

18. The gas turbine engine according to claim 17, The lubrication assembly includes a lubricating oil supply line that provides lubricating fluid flow to the motor reservoir, and in, The lubrication assembly is configured to provide a flow of lubricating oil to the lubricating oil supply line at temperatures below 275°F.

19. The gas turbine engine according to claim 18, The lubrication assembly includes a heat exchanger that reduces the temperature of the lubricating oil flow supplied to the lubricating oil supply line.

20. The gas turbine engine according to claim 16, A sealing cavity assembly includes one or more fluid seals that at least partially define a sealing cavity and are configured to prevent lubricating fluid from the motor reservoir from entering the sealing cavity, wherein the motor is enclosed within the sealing cavity.

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