Power transmission system

Abstract

A power transfer system includes a first pressure spool of a gas turbine engine configured to rotate and compress a working fluid to a first pressure; a first motor connected to the first pressure spool, the first motor including a first stator; a second pressure spool of the gas turbine engine configured to rotate and compress the working fluid to a second pressure different from the first pressure; a second motor connected to the second pressure spool, the second motor including a second stator; a first power converter connected with one of the first motor or the second motor; and an electrical connector including a main portion connecting the first stator of the first electric machine with the second stator of the second electric machine while bypassing the first power converter and a branch portion connecting the main portion with the first power converter.

Description

Priority information

[0001] This application claims priority to Indian Patent Application Serial No. 202411082271, filed on October 28, 2024. Technical Field

[0002] This disclosure relates to an electrical transmission system for a pressure spool in a gas turbine engine. Background Technology

[0003] Aircraft launch vehicles use various power sources to drive one or more propellers, which generate thrust for the launch vehicle. Many launch vehicles use gas turbine engines with two or more spools of a turbine, which may include one or more electric motors operating with the spools. For example, an electric motor can be driven by the high-voltage spools of a gas turbine engine, thereby generating electricity that can be used elsewhere on the aircraft launch vehicle. While gas turbine engines have made significant progress over the years, it may be beneficial to explore the integration of other electric motors with gas turbine engines. Improvements in electric motor integration are useful in this field. Attached Figure Description

[0004] The complete and enabling disclosure of this disclosure, including its best mode, is set forth in the specification with reference to the accompanying drawings, for those skilled in the art, wherein:

[0005] Figure 1 This is a schematic diagram of an exemplary gas turbine engine.

[0006] Figure 2 This is a schematic diagram of an exemplary power transmission system for the electric motor of a gas turbine engine.

[0007] Figure 3 This is a schematic diagram of an exemplary power transmission system, in which a low-voltage spool is connected to a doubly-fed motor.

[0008] Figure 4 This is a schematic diagram of another exemplary power transmission system, in which a high-voltage spool is connected to a doubly-fed motor. Detailed Implementation

[0009] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerals and letter reference numerals to denote features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to denote similar or analogous portions of the present disclosure.

[0010] The term "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 superior to or advantageous to other implementations. Furthermore, unless explicitly stated otherwise, all embodiments described herein should be considered exemplary.

[0011] Unless the context clearly indicates otherwise, the singular forms “a,” “one,” and “the” include plural references.

[0012] As used herein, the terms “first,” “second,” and “third,” and other serial numbers are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0013] This disclosure generally relates to an electric power transmission system for a gas turbine engine, wherein the gas turbine engine includes two or more spools (e.g., two or more spools respectively connecting two or more turbine and compressor components). An electric motor may be coupled to a first pressure spool of the gas turbine engine (e.g., a high-pressure shaft rotatably coupled to a high-pressure compressor and a high-pressure turbine). The electric motor may be configured to operate as a generator, wherein mechanical power is extracted from the first pressure spool and converted into electricity. The electric motor (also referred to herein as a first motor) can transmit the electricity to a second motor coupled to a second pressure spool of the gas turbine engine (e.g., a low-pressure shaft rotatably coupled to a low-pressure compressor and a low-pressure turbine).

[0014] When the second motor is a doubly-fed motor, the first motor directly transmits at least a portion of the power to the second motor. That is, the stator windings of the first and second motors are connected to each other without a power converter, providing a direct power transmission path between the first and second pressure shafts. This direct connection improves the power transmission efficiency from the first motor to the second motor.

[0015] See now Figure 1 A schematic cross-sectional view of a gas turbine engine 100 is provided according to an exemplary embodiment of the present disclosure. Specifically, Figure 1 An engine with a rotor assembly having single-stage ductless rotor blades is provided. In this way, the rotor assembly may be referred to herein as a "ductless fan," or the entire engine as a "ductless engine." Furthermore, Figure 1 The gas turbine engine 100 includes a third flow that extends from the compressor section to the rotor assembly flow path above the turbine, which will be explained in more detail below.

[0016] For reference, the gas turbine engine 100 defines an axial direction A, a radial direction R, and a circumferential direction C. Furthermore, the gas turbine engine 100 defines an axial centerline or longitudinal axis 112 extending along the axial direction A. Typically, the axial direction A extends parallel to the longitudinal axis 112, the radial direction R extends outward and inward from the longitudinal axis 112 in a direction orthogonal to the axial direction A, and the circumferential direction extends 360° around the longitudinal axis 112. The gas turbine engine 100 extends between a front end 114 and a rear end 116, for example, along the axial direction A.

[0017] The gas turbine engine 100 includes a turbine 120 and a rotor assembly, also referred to as a fan section 150 located upstream thereon. Typically, the turbine 120 includes a compressor section, a combustion section, a turbine section, and an exhaust section in a series flow sequence. Specifically, as... Figure 1 As shown, turbine 120 includes a core shroud 122 defining an annular core inlet 124. The core shroud 122 also at least partially surrounds the low-pressure system and the high-pressure system. For example, the core shroud 122 at least partially surrounds and supports a turbocharger or low-pressure (“LP”) compressor (referred to herein as LP compressor 126) for pressurizing air entering turbine 120 through the annular core inlet 124. A high-pressure (“HP”) multi-stage axial compressor (referred herein as HP compressor 128) receives the pressurized air from LP compressor 126 and further increases the air pressure. The pressurized air flows downstream to combustor 130 in the combustion section, where fuel is injected into the pressurized air flow and ignited to increase the temperature and energy level of the pressurized air.

[0018] It should be understood that, as used herein, the terms “high / low speed” and “high / low pressure” may be used interchangeably for high-pressure / high-speed systems and low-pressure / low-speed systems. Furthermore, it should be understood that the terms “high” and “low” are used in the same context to distinguish between the two systems and do not imply any absolute speed and / or pressure values.

[0019] High-energy combustion products flow downstream of combustor 130 to HP turbine 132. HP turbine 132 drives HP compressor 128 via HP shaft 136. In this respect, HP turbine 132 is drivenly coupled to HP compressor 128. High-energy combustion products then flow into LP turbine 134. LP turbine 134 drives components of LP compressor 126 and fan section 150 via LP shaft 138. In this respect, LP turbine 134 is drivenly coupled to components of LP compressor 126 and fan section 150. In this example embodiment, LP shaft 138 is coaxial with HP shaft 136. After driving each turbine 132, 134, combustion products are discharged from turbine 120 through turbine exhaust nozzle 140. LP compressor 126, LP turbine 134, and LP shaft 138 are generally referred to as the “LP spool” of gas turbine engine 100. HP compressor 128, HP turbine 132, and HP shaft 136 are generally referred to as the “HP spool” of gas turbine engine 100.

[0020] Accordingly, turbine 120 defines a working gas flow path or core duct 142 extending between an annular core inlet 124 and turbine exhaust nozzle 140. Core duct 142 is an annular duct located approximately inside the core shroud 122 in the radial direction R. Core duct 142 (e.g., through the working gas flow path of turbine 120) may be referred to as a second flow.

[0021] Fan section 150 includes fan 152, which is the primary fan in this example embodiment. For Figure 1 In the embodiment shown, the fan 152 is an open rotor or ductless fan 152. Thus, the gas turbine engine 100 can be referred to as an open rotor engine.

[0022] As shown in the figure, fan 152 includes an array of fan blades 154. Figure 1 (Only one is shown). Fan blades 154 can rotate, for example, about longitudinal axis 112. As described above, fan 152 is driven connected to LP turbine 134 via LP shaft 138. For Figure 1 In the embodiment shown, fan 152 is connected to LP shaft 138 via reduction gearbox 155, for example in an indirect drive or gear drive configuration.

[0023] Furthermore, the array of fan blades 154 can be arranged at equal intervals around the longitudinal axis 112. Each fan blade 154 has a root and a tip, and a span defined between them. Each fan blade 154 defines a central blade axis 156. In this embodiment, each fan blade 154 of the fan 152 is capable of rotating about its central blade axis 156, for example, in unison with each other. One or more actuators 158 are provided to facilitate this rotation, and are therefore used to change the pitch of the fan blades 154 about their respective central blade axes 156.

[0024] Fan section 150 also includes a fan guide vane array 160, which includes fan guide vanes 162 arranged around a longitudinal axis 112. Figure 1 (Only one is shown in the image). In this embodiment, the fan guide vane 162 cannot rotate about the longitudinal axis 112. Each fan guide vane 162 has a root and a tip, and a span defined between them. The fan guide vane 162 can be as follows: Figure 1 The fan guide vane 162 may be left uncovered or may be covered by an annular shield that is spaced outward from the tip of the fan guide vane 162 along the radial direction R or attached to the fan guide vane 162.

[0025] Each fan guide vane 162 defines a central blade axis 164. In this embodiment, each fan guide vane 162 of the fan guide vane array 160 is rotatable about its respective central blade axis 164, for example, in sync with each other. One or more actuators 166 are provided to facilitate this rotation and are therefore used to change the pitch of the fan guide vanes 162 about their respective central blade axes 164. However, in other embodiments, each fan guide vane 162 may be fixed or not tiltable about its central blade axis 164. The fan guide vanes 162 are mounted on a fan shroud 170.

[0026] like Figure 1 As shown, in addition to the ductless fan 152, a ducted fan 184 is also included at the rear of fan 152, such that the gas turbine engine 100 includes both ducted and ductless fans, both used to generate thrust by the movement of air that does not pass through at least a portion of the turbine 120 (e.g., in the depicted embodiment, not through the HP compressor 128 and the combustion section). The ducted fan 184 is rotatable about the same axis as the fan blades 154 (e.g., longitudinal axis 112). In the described embodiment, the ducted fan 184 is driven by the LP turbine 134 (e.g., coupled to the LP shaft 138). In the described embodiment, as described above, fan 152 may be referred to as the primary fan, and ducted fan 184 may be referred to as the secondary fan. It should be understood that the terms "primary" and "secondary" are convenient terms and do not imply any particular importance, power, etc.

[0027] The duct fan 184 includes multiple fan blades arranged in a single stage. Figure 1 (Not separately marked), so that the duct fan 184 can be referred to as a single-stage fan. The fan blades of the duct fan 184 can be arranged at equal intervals around the longitudinal axis 112. Each blade of the duct fan 184 has a root and a tip and a span defined between them.

[0028] The fan shroud 170 annularly surrounds at least a portion of the core shroud 122 and is generally positioned radially R outside at least a portion of the core shroud 122. Specifically, a downstream section of the fan shroud 170 extends above the front portion of the core shroud 122 to define a fan duct flow path, or simply a fan duct 172. According to this embodiment, the fan flow path or fan duct 172 can be understood as forming at least a portion of a third flow of the gas turbine engine 100.

[0029] Air intake enters fan duct 172 through fan duct inlet 176 and exits through fan exhaust nozzle 178, thereby generating thrust. Fan duct 172 is an annular duct, positioned approximately outside core duct 142 in the radial direction R. Fan shroud 170 and core shroud 122 are connected together and are supported by a plurality of substantially radially extending, circumferentially spaced fixed supports 174. Figure 1 (Only one is shown in the image) Support. The fixed support 174 may each have an aerodynamic profile to guide the airflow therefrom. Other supports besides the fixed support 174 may be used to connect and support the fan shroud 170 and / or the core shroud 122. In many embodiments, the fan duct 172 and the core duct 142 may extend at least partially (generally axially) on opposite sides (e.g., opposite radial sides) of the core shroud 122. For example, the fan duct 172 and the core duct 142 may extend directly from the fan duct separator or leading edge 144 of the core shroud 122, and may extend axially together partially on opposite radial sides of the core shroud 122.

[0030] The gas turbine engine 100 also defines or includes an inlet duct 180. The inlet duct 180 extends between an engine inlet 182 and an annular core inlet 124 / fan duct inlet 176. The engine inlet 182 is generally defined at the front end of the fan shroud 170 and positioned along the axial direction A between the fan 152 and the fan guide vane array 160. The inlet duct 180 is an annular duct disposed along the radial direction R inside the fan shroud 170. Air flowing downstream along the inlet duct 180 is diverted by a fan duct separator or the leading edge 144 of the core shroud 122 into the core duct 142 and the fan duct 172, and is not necessarily uniform. In the described embodiment, the inlet duct 180 is wider along the radial direction R than the core duct 42. The inlet duct 180 is also wider along the radial direction R than the fan duct 172.

[0031] It is noteworthy that, for the described embodiment, the gas turbine engine 100 includes one or more features to improve the efficiency of third-flow thrust (e.g., thrust generated by the airflow exiting through fan duct 172 and exhaust through fan exhaust nozzle 178, at least partially generated by the ducted fan 184). Specifically, the gas turbine engine 100 also includes an array of inlet guide vanes 186 positioned in an inlet duct 180 upstream of the ducted fan 184 and downstream of the engine inlet 182. The array of inlet guide vanes 186 is arranged about a longitudinal axis 112. For this embodiment, the inlet guide vanes 186 cannot rotate about the longitudinal axis 112. Each inlet guide vane 186 defines a central blade axis (not labeled for clarity) and is rotatable about its respective central blade axis, for example, coherently with each other. In this way, the inlet guide vanes 186 can be considered as variable geometry components. One or more actuators 188 are provided to facilitate this rotation and are therefore available for changing the pitch of the inlet guide vanes 186 about their respective central blade axes. However, in other embodiments, each inlet guide vane 186 may be fixed or may not be tilted about its central vane axis.

[0032] Furthermore, located downstream of the ducted fan 184 and upstream of the fan duct inlet 176, the gas turbine engine 100 includes an array of outlet guide vanes 190. Like the array of inlet guide vanes 186, the array of outlet guide vanes 190 cannot rotate about the longitudinal axis 112. However, in the described embodiment, unlike the array of inlet guide vanes 186, the array of outlet guide vanes 190 is configured as fixed-pitch outlet guide vanes.

[0033] Furthermore, it should be understood that, in the described embodiment, the fan exhaust nozzle 178 of the fan duct 172 is also configured as a variable geometry exhaust nozzle. In this way, the gas turbine engine 100 includes one or more actuators 192 for adjusting the variable geometry exhaust nozzle. For example, the variable geometry exhaust nozzle may be configured to change the total cross-sectional area (e.g., the area of ​​the nozzle in a plane perpendicular to the longitudinal axis 112) to adjust the amount of thrust generated based on one or more engine operating conditions (e.g., the temperature, pressure, mass flow rate, etc. of the airflow through the fan duct 172). A fixed geometry exhaust nozzle may also be used.

[0034] Under one or more engine operating conditions, the combination of an array of inlet guide vanes 186 upstream of the ducted fan 184, an array of outlet guide vanes 190 downstream of the ducted fan 184, and the fan exhaust nozzle 178 can result in more efficient generation of third-flow thrust. Furthermore, by introducing variability in the geometry of the inlet guide vanes 186 and the fan exhaust nozzle 178, the gas turbine engine 100 can generate more effective third-flow thrust over a wider range of engine operating conditions, including takeoff and climb (which typically require the highest total engine thrust) and cruise (which typically requires a lower total engine thrust).

[0035] In addition, still refer to Figure 1 In an exemplary embodiment, the air passing through fan duct 172 may be colder (e.g., at a lower temperature) than one or more fluids used in turbine 120. Thus, one or more heat exchangers 194 may be positioned in thermal communication with fan duct 172. For example, one or more heat exchangers 194 may be positioned within fan duct 172 and used to utilize the air passing through fan duct 172 to cool one or more fluids from the core engine as a resource for removing heat from fluids such as compressor bleed air, oil, or fuel.

[0036] Although not shown, heat exchanger 194 may be an annular heat exchanger extending substantially 360 degrees (e.g., at least 300 degrees, e.g., at least 330 degrees) within fan duct 172. In this way, heat exchanger 194 can effectively utilize air passing through fan duct 172 to cool one or more systems of gas turbine engine 100 (e.g., lubrication system, compressor bleed air, electrical components, etc.). Heat exchanger 194 uses air passing through fan duct 172 as a radiator, accordingly raising the temperature of air downstream of heat exchanger 194 and exiting fan exhaust nozzle 178.

[0037] However, it should be understood that the exemplary gas turbine engine 100 is provided by way of example only. In other exemplary embodiments, the gas turbine engine 100 may have any other configuration. For example, in other exemplary embodiments, the turbine 120 may have any other number and arrangement of shafts, spools, compressors, turbines, etc. Further, in other exemplary embodiments, the gas turbine engine 100 may alternatively be configured as a ducted turbofan engine (including an outer nacelle surrounding a portion of the fan 152 and the turbine 120); a direct-drive gas turbine engine (which may not include a reduction gearbox, such as reduction gearbox 155); a fixed-pitch gas turbine engine (which may not include a variable-pitch fan, such as fan 152); a two-flow gas turbine engine (which may not include fan duct 172); etc.

[0038] See now Figure 2The diagram illustrates an electric power transmission system 200 for a gas turbine engine 100. The electric power transmission system 200 includes a first pressure spool 202, a second pressure spool 204, a first motor 206, a second motor 208, a first power converter 210 connecting the first motor 206 and the second motor 208, and an electrical connector 212. The electric power transmission system 200 transmits power from one of the first and second pressure spools 202, 204 to the other. More specifically, the electric power transmission system 200 is used to extract mechanical power from one spool of the gas turbine engine 100 and transmit the mechanical power to the other spool of the gas turbine engine 100 via electromagnetic interaction, as described below. When the gas turbine engine 100 includes the first motor 206 and the second motor 208, the gas turbine engine 100 can be a “hybrid-electric” gas turbine engine.

[0039] The first pressure spool 202 is configured to rotate and compress the working fluid to a first pressure, thereby generating mechanical power. Figure 2 In the example, the first pressure spool 202 is a high-pressure (HP) spool including an HP compressor 128, an HP turbine 132, and an HP shaft 136. In this form, the first pressure shaft 203 of the first pressure spool 202 corresponds to the HP shaft 136.

[0040] The first motor 206 is electrically connected to the first pressure wire shaft 202. The first motor 206 includes a first stator 214 having at least one first winding 216 and a first permanent magnet ( Figure 2 A first rotor 218 (not shown). A first stator 214 may be fixed to the gas turbine engine 100 such that it remains stationary relative to the rotating HP shaft 136. When operating as a generator, the first rotor 218 is configured to rotate in response to the rotation of the HP shaft 136, wherein the relative rotation of at least one first permanent magnet induces a current in at least one first winding of the first motor 206 via the electromagnetic interaction between the first stator 214 and the first rotor 218. Thus, mechanical power from the first pressure line shaft 202 is converted into electrical power. When operating as a motor, the excitation of at least one first winding 216 generates a magnetic field that interacts with the magnetic field of at least one first permanent magnet 146. The interaction of the magnetic fields generates a force on at least one first permanent magnet 146, which in turn generates a reaction force on the HP shaft 136. The HP shaft 136 can be accelerated by using the first motor 206 as a motor and can be decelerated by using the first motor 206 as a generator.

[0041] The second pressure spool 204 of the gas turbine engine 100 is configured to rotate and compress the working fluid to a second pressure different from the first pressure, thereby generating mechanical power. Figure 2In this example, the second pressure spool 204 is a low-pressure (LP) spool including an LP compressor 126, an LP turbine 134, and an LP shaft 138. In this configuration, the second pressure shaft 205 of the second pressure spool 204 corresponds to the LP shaft 138. The first pressure shaft 203 and the second pressure shaft 205 are concentric about a common axis. Specifically, the first pressure shaft 203 extends radially outward from the second pressure shaft 205, such that the second pressure shaft 205 rotates within the cavity 220 defined by the first pressure shaft 203.

[0042] It should be understood that the use of "first" and "second" for pressure spools refers to either the HP spool or the LP spool. That is, the first pressure spool 202 can be either the HP spool or the LP spool, and the second pressure spool 204 can be either the HP spool or the LP spool.

[0043] The second motor 208 is electrically connected to the second pressure shaft 204. The second motor 208 includes a second stator 222 having at least one second winding 224 and a second rotor 226 having at least one second permanent magnet (not shown). The second stator 222 can be fixed to the gas turbine engine 100 such that it remains stationary relative to the rotating LP shaft 138. Like the first motor 206, the second motor 208 can be driven by the second pressure shaft 204 to convert mechanical power into electrical power.

[0044] The first motor 206 is connected to the second motor 208 via an electrical connector 212. The electrical connector 212 includes a main portion 228 connecting the first stator 214 of the first motor 206 to the second stator 222 of the second motor 208. Specifically, the main portion 228 of the electrical connector 212 directly connects the first stator 214 to the second stator 222 to bypass the first power converter 210 and transmit power between the first and second motors 206 and 208. The electrical connector 212 includes a branch portion 230 connecting the main portion 228 to the first power converter 210. In this configuration, power is transmitted from the first motor 206 to the second motor 208 without using the first power converter 210, and the first power converter 210 can be selected at a rated power lower than the total amount of power transmitted. That is, the main portion 228 is configured to transmit more power between the first motor 206 and the second motor 208 than the first power converter 210.

[0045] One of the first motor 206 or the second motor 208 is a doubly-fed motor including a first set of windings and a second set of windings. Figure 2In the example, the second motor 208 is a doubly fed motor (DFM), and at least one second winding 224 includes a first set of second windings 232 and a second set of second windings 234. Specifically, the second set of second windings 234 can be accessed via slip rings. The other motor among the first or second motors 206, 208 can be a permanent magnet synchronous motor (PMSM).

[0046] The power transmission system 200 may include a second power converter 236 electrically connected to one of the first stator 214 or the second stator 222. Specifically, the second power converter 236 may be connected to one of the first and second motors 206, 208, i.e., a DFM. In this configuration, the main portion 228 of the electrical connector 212 is connected to a first set of windings (e.g., Figure 2 The first set of second windings 232), and the second power converter 236 is connected to the second set of windings (e.g., Figure 2 The second set of windings 234 (in the second group). In this configuration, the second set of windings is connected to the second rotor 226 via slip rings (not shown). The first power converter 210 and the second power converter 236 can be AC / AC converters configured to transmit alternating current. Alternatively, the second power converter 236 can be current-controlled.

[0047] As a DFM, the second motor 208 is configured to output a constant voltage as the rotational speed of the first pressure shaft 202 changes. More specifically, as the rotational speed of the second rotor 226 changes, the current in the second stator 222 (provided by electrical connector 212) is regulated so that the current output by the second motor 208 is a constant current. In particular, the second power converter 236 reduces the current variation from the second motor 208 by providing slip power from the first motor 206. Since the amount of slip power used to maintain a constant current output is much lower than the amount of total power output by the second motor 208, the rated voltages of the first power converter 210 and the second power converter 236 are lower than those of conventional components, in which all power is transmitted through the first power converter 210 and the second power converter 236.

[0048] Please see now Figure 3 , showed Figure 2 A schematic diagram of the power transmission system 200 is provided. Specifically, the first pressure spool 202 is an HP spool, the second pressure spool 204 is an LP spool, the first motor 206 is a PMSM, and the second motor 208 is a DFM. The main part 228 of the electrical connector 212 directly connects the first motor 206 to the second motor 208, and the branch part 230 connects the first motor 206 to the first power converter 210. The second power converter 236 is connected to both the second motor 208 and the first power converter 210.

[0049] Specifically, the first motor 206 includes a first stator 214 and a first rotor 218, with multiple wires 238 of the electrical connector 212 connected to the first stator 214. Specifically, each of the multiple wires 238 is connected at its respective attachment point 240 to one or more first windings 216 of the first stator 214. The first rotor 218 is rotatable within the first stator 214 to generate or receive electricity.

[0050] The second motor 208 includes a second stator 222 and a second rotor 226. A main portion 228 of the electrical connector 212 is connected to the second stator 222. Specifically, multiple wires 238 of the electrical connector 212 are connected to one or more second windings 224 of the second stator 222 at their respective attachment points 242. The second power converter 236 includes multiple wires 244, which are connected to the second rotor 226 at their respective attachment points 246.

[0051] The power transmission system 200 may include a circuit breaker 248. When the current in the main portion 228 of the electrical connector 212 exceeds a current threshold, the circuit breaker 248 disconnects the first motor 206 from the second motor 208. The current threshold may be determined based on the maximum permissible power transfer between the first motor 206 and the second motor 208.

[0052] See now Figure 4 A schematic diagram of another power transmission system 300 is shown. Specifically, the first pressure spool 302 is an HP spool, the second pressure spool 304 is an LP spool, the first motor 306 is a DFM, and the second motor 308 is a PMSM. The electrical connector 310 includes a main portion 312 that directly connects the first motor 306 to the second motor 308, and a branch portion 314 that connects the second motor 308 to a power converter 316. The electrical connector 310 may include a circuit breaker 318 as described above. The second power converter 320 is connected to the first motor 306 and the power converter 316. Both the power converter 316 and the second power converter 320 may be AC / AC converters. Alternatively, the second power converter 320 may be current-controlled.

[0053] The first motor 306 includes a first stator 322 and a first rotor 324. A main portion 312 of an electrical connector 310 is connected to the first stator 322. Specifically, multiple wires of the electrical connector 310 are connected to one or more first windings 326 of the first stator 322 at respective attachment points 328. The second power converter 320 includes multiple wires connected to the first rotor 324 at respective attachment points 330.

[0054] The second motor 308 includes a second stator 332 and a second rotor 334, with multiple wires of the electrical connector 310 connected to the second stator 332. Specifically, each of the multiple wires is connected at its respective attachment point 338 to one or more second windings 336 of the second stator. The second rotor 334 is rotatable within the second stator 332 to generate or receive electricity.

[0055] Using a DFM as one of a set of motors in a hybrid electric gas turbine engine ensures a consistent electrical output as the pressure spool rotates. The direct connection between the motor stators increases power transmission without requiring a power converter with a high rated voltage. This power transmission reduces losses between the pressure spools, improving the efficiency of the gas turbine engine.

[0056] The following items provide further details:

[0057] An electrical transmission system includes: a first pressure spool of a gas turbine engine configured to rotate and compress a working fluid to a first pressure; a first motor connected to the first pressure spool, the first motor including a first stator; a second pressure spool of the gas turbine engine configured to rotate and compress the working fluid to a second pressure different from the first pressure; a second motor connected to the second pressure spool, the second motor including a second stator; a first power converter connected to one of the first motor or the second motor; and an electrical connector including a portion connecting the first stator of the first motor to the second stator of the second motor while bypassing a main portion of the first power converter and a branch portion connecting the main portion to the first power converter.

[0058] The power transmission system according to any of the foregoing clauses further includes a second power converter electrically connected to one of the first stator or the second stator.

[0059] In any of the preceding clauses of the power transmission system, the first power converter is electrically connected to the second power converter.

[0060] According to any of the preceding clauses, the power transmission system wherein the electrical connector is configured to transmit power between the first motor and the second motor.

[0061] According to any of the preceding clauses, in the power transmission system, the first pressure spool is configured to generate mechanical power, and the first motor is configured to convert the mechanical power into electrical power that can be transmitted to the second motor via the main portion of the electrical connector.

[0062] In any of the preceding clauses, the power transmission system wherein the first pressure spool is a high-voltage spool.

[0063] In any of the preceding clauses of the power transmission system, the second pressure spool is a low-voltage spool.

[0064] In any of the preceding clauses of the power transmission system, the first pressure spool is a low-voltage spool.

[0065] According to any of the preceding clauses, in the power transmission system, one of the first motor or the second motor is a doubly fed motor including a first set of windings and a second set of windings.

[0066] The power transmission system according to any of the foregoing clauses further includes a second power converter connected to the first power converter, wherein the main portion of the electrical connector is connected to the first set of windings, and the second power converter is connected to the second set of windings.

[0067] According to any of the preceding clauses, the power transmission system wherein the first motor or the other of the second motor is a permanent magnet synchronous motor.

[0068] The power transmission system according to any of the foregoing clauses further includes a circuit breaker configured to disconnect the first motor from the second motor.

[0069] According to any of the preceding clauses, the power transmission system wherein the first motor is configured to supply power to the second motor via the main portion of the electrical connector.

[0070] According to any of the preceding clauses, in the power transmission system, the first pressure spool is configured to power the second pressure spool via the first motor, the main portion of the electrical connector, and the second motor.

[0071] According to any of the preceding clauses of the power transmission system, the main portion of the electrical connector is configured to transmit power from the first motor to the second motor and from the second motor to the first motor.

[0072] According to any of the preceding clauses of the power transmission system, wherein the first pressure spool includes a first pressure shaft, and the second pressure spool includes a second pressure shaft, and the first pressure shaft and the second pressure shaft are concentric about a common axis.

[0073] According to any of the preceding clauses of the power transmission system, wherein the second motor is configured to output a constant current as the rotational speed of the first pressure spool changes.

[0074] According to any of the preceding clauses, the power transmission system wherein the first power converter is an AC / AC converter.

[0075] According to any of the preceding clauses of the power transmission system, the main portion of the electrical connector is configured to transmit more power from the first motor to the second motor than the first power converter.

[0076] A gas turbine engine includes an electric transmission system comprising: a first pressure spool configured to rotate and compress a working fluid to a first pressure; and a first motor connected to the first pressure spool, the first motor including a first stator.

[0077] A second pressure spool configured to rotate and compress the working fluid to a second pressure different from the first pressure; a second motor connected to the second pressure spool, the second motor including a second stator; a first power converter connected to either the first motor or the second motor; and an electrical connector including a portion that connects the first stator of the first motor to the second stator of the second motor while bypassing a main portion of the first power converter and a branch portion that connects the main portion to the first power converter.

[0078] The gas turbine engine according to any of the foregoing clauses further includes a second power converter electrically connected to one of the first stator or the second stator.

[0079] The gas turbine engine according to any of the foregoing clauses, wherein the first power converter is electrically connected to the second power converter.

[0080] According to any of the foregoing clauses, the gas turbine engine wherein the electrical connector is configured to transmit power between the first motor and the second motor.

[0081] According to any of the foregoing clauses, in a gas turbine engine, wherein the first pressure spool is configured to generate mechanical power, and the first motor is configured to convert the mechanical power into electrical power that can be transmitted to the second motor via the main portion of the electrical connector.

[0082] In any of the preceding clauses, the gas turbine engine wherein the first pressure spool is a high-pressure spool.

[0083] In any of the preceding clauses, the gas turbine engine wherein the second pressure spool is a low-pressure spool.

[0084] In any of the preceding clauses, the gas turbine engine wherein the first pressure spool is a low-pressure spool.

[0085] The gas turbine engine according to any of the foregoing clauses, wherein one of the first motor or the second motor is a doubly fed motor including a first set of windings and a second set of windings.

[0086] The gas turbine engine according to any of the foregoing clauses further includes a second power converter connected to the first power converter, wherein the main portion of the electrical connector is connected to the first set of windings, and the second power converter is connected to the second set of windings.

[0087] The gas turbine engine according to any of the foregoing clauses, wherein the other of the first motor or the second motor is a permanent magnet synchronous motor.

[0088] The gas turbine engine according to any of the foregoing clauses further includes a circuit breaker configured to disconnect the first motor from the second motor.

[0089] The gas turbine engine according to any of the foregoing clauses, wherein the first motor is configured to supply power to the second motor via the main portion of the electrical connector.

[0090] According to any of the foregoing clauses, in a gas turbine engine, wherein the first pressure spool is configured to power the second pressure spool via the first motor, the main portion of the electrical connector, and the second motor.

[0091] According to any of the foregoing clauses of the gas turbine engine, the main portion of the electrical connector is configured to transmit power from the first motor to the second motor and from the second motor to the first motor.

[0092] According to any of the preceding clauses, in a gas turbine engine, the first pressure axis includes a first pressure axis, and the second pressure axis includes a second pressure axis, and the first pressure axis and the second pressure axis are concentric about a common axis.

[0093] According to any of the foregoing clauses, the second motor is configured to output a constant current as the rotational speed of the first pressure spool changes.

[0094] According to any of the foregoing clauses, the gas turbine engine wherein the first power converter is an AC / AC electric converter.

[0095] According to any of the foregoing clauses, in a gas turbine engine, the main portion of the electrical connector is configured to transmit more power from the first motor to the second motor than the first power converter.

[0096] This written description uses examples to disclose the contents of this disclosure, including best practices, and also enables those skilled in the art to practice the invention, including making and using any device or system and performing any combined methods. The patentable scope of this disclosure is defined by the claims, but may include other examples that would 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 are indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A power transmission system, characterized in that, include: A first pressure spool of a gas turbine engine, the first pressure spool being configured to rotate and compress the working fluid to a first pressure; A first motor is connected to the first pressure shaft, and the first motor includes a first stator; The second pressure spool of the gas turbine engine is configured to rotate and compress the working fluid to a second pressure different from the first pressure; A second motor is connected to the second pressure shaft, and the second motor includes a second stator; A first power converter, the first power converter being connected to one of the first motor or the second motor; and An electrical connector comprising connecting the first stator of the first motor to the second stator of the second motor while bypassing the main portion of the first power converter and a branch portion connecting the main portion to the first power converter.

2. The power transmission system according to claim 1, characterized in that, It further includes a second power converter, which is electrically connected to one of the first stator or the second stator.

3. The power transmission system according to claim 2, characterized in that, The first power converter is electrically connected to the second power converter.

4. The power transmission system according to claim 1, characterized in that, The electrical connector is configured to transmit power between the first motor and the second motor.

5. The power transmission system according to claim 4, characterized in that, The first pressure spool is configured to generate mechanical power, and the first motor is configured to convert the mechanical power into electrical power that can be transmitted to the second motor via the main portion of the electrical connector.

6. The power transmission system according to claim 1, characterized in that, The first pressure spool is a high-pressure spool.

7. The power transmission system according to claim 6, characterized in that, The second pressure line spool is a low-pressure line spool.

8. The power transmission system according to claim 1, characterized in that, The first pressure spool is a low-pressure spool.

9. The power transmission system according to claim 1, characterized in that, One of the first motor or the second motor is a doubly fed motor including a first set of windings and a second set of windings.

10. The power transmission system according to claim 9, characterized in that, The device further includes a second power converter connected to the first power converter, wherein the main portion of the electrical connector is connected to the first set of windings, and the second power converter is connected to the second set of windings.

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