Power transfer system for gas turbine engine

Abstract

A gas turbine engine having a first pressure spool and a second pressure spool includes a power transfer system for transferring mechanical power between the first pressure spool and the second pressure spool. The first pressure spool may include a first motor for converting mechanical power from the first pressure spool to first electrical power. A coupling motor having a first coupling rotor and a second coupling rotor may be rotationally coupled to the first pressure spool and the second pressure spool, respectively. The coupled motor is configured to receive output power (e.g., output power from the AC / AC converter) to drive windings of the coupled motor to enable power transfer between the first pressure spool and the second pressure spool. The AC / AC converter may be electrically disposed between the first pressure spool and the second pressure spool.

Description

Technical Field

[0001] The present invention relates to a power transmission system for a gas turbine engine. Background Art

[0002] Aircraft use a variety of power sources to drive one or more propellers that generate thrust for the aircraft. Many aircraft use gas turbine engines that have two or more turbine spools that may include one or more electric motors that operate in conjunction with the spools. For example, an electric motor may be driven by the low-pressure spool of the gas turbine engine to generate electrical power that can be used elsewhere in the aircraft. Although gas turbine engines have made great strides over the years, it may be beneficial to investigate the incorporation of other electric motors into gas turbine engines. However, in the process of integrating new electric motors, it may be important to ensure that the new technology does not introduce other inefficiencies, such as excess weight. Improvements in electric motor integration would be useful in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] A full and enabling disclosure of the present disclosure, including the best mode thereof, is set forth to those skilled in the art in the specification which proceeds with reference to the accompanying drawings, in which:

[0004] Figure 1 is a schematic perspective view of an aerial vehicle according to aspects of the present disclosure.

[0005] Figure 2 is a schematic diagram of a gas turbine engine according to aspects of the present disclosure.

[0006] Figure 3 is a schematic diagram of a power transmission system according to aspects of the present disclosure.

[0007] Figure 4 is a schematic diagram of a coupled electric machine according to an exemplary aspect of the present disclosure.

[0008] Figure 5 is a power flow diagram of an embodiment of a power transmission system according to an exemplary aspect of the present disclosure.

[0009] FIG6 is a schematic diagram of a conventional prior art system.

[0010] Figure 7 is a schematic diagram of a power transmission system according to aspects of the present disclosure.

[0011] Figure 8 is a schematic diagram of a power transmission system according to aspects of the present disclosure.

[0012] Figure 9 is a schematic diagram of a controller according to an exemplary aspect of the present disclosure.

[0013] Figure 10 is a flow chart of a method of operating a power transmission system of the present disclosure.

[0014] Figure 11 is a schematic diagram of a gas turbine engine according to aspects of the present disclosure. DETAILED DESCRIPTION

[0015] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. The same or similar designations in the drawings and the description have been used to refer to the same or similar parts of the present disclosure.

[0016] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0017] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0018] For example, the term "at least one" in the context of "at least one of A, B, and C" refers to A alone, B alone, C alone, or any combination of A, B, and C.

[0019] The phrases "from X to Y" and "between X and Y" each refer to a numerical range including the endpoints (ie, to a numerical range that includes X and Y).

[0020] The present disclosure generally relates to a power transmission system for a gas turbine engine, wherein the gas turbine engine includes two or more spools (e.g., two or more shafts respectively connected to two or more turbine and compressor elements). An electric motor can be coupled to a first pressure spool of the gas turbine engine (e.g., a low-pressure spool rotationally coupled to a low-pressure compressor and a low-pressure turbine). The electric motor can be configured to operate as a generator, extracting mechanical power from the first pressure spool and converting it into electrical power. A coupled electric motor can be coupled to the first and second pressure spools of the gas turbine engine, wherein the second pressure spool can be, for example, a high-pressure spool rotationally coupled to a high-pressure compressor and a high-pressure turbine. The coupled electric motor can be a dual-rotor electric motor having a first coupled rotor and a second coupled rotor, the first coupled rotor rotationally coupled to the first pressure spool and the second coupled rotor rotationally coupled to the second pressure spool. The coupled electric motor can include armature windings on one of the first coupled rotor or the second coupled rotor, and permanent magnets on the other of the first coupled rotor or the second coupled rotor. Current in the armature windings and relative motion between the first coupled rotor and the second coupled rotor can facilitate mechanical power transmission between the first and second pressure spools.

[0021] The electrical power generated by the first motor by extracting mechanical power from the first pressure spool can be provided to the coupling motor to enable mechanical power transfer between the spools. An AC / AC (alternating current / alternating current) converter can be electrically positioned between the first motor and the coupling motor to convert the AC power generated by the motor to AC power used to power the coupling motor. If power transfer between the first and second pressure spools is desired, a controller can be used to regulate the operation of the AC / AC converter. The AC / AC converter can include an AC / DC (alternating current / direct current) converter for receiving the first power output from the first motor and converting it to DC power. The AC / AC converter can also include a DC / AC converter for converting the DC power to AC power suitable for use by the coupling motor. A DC link capacitor can be used to electrically couple the AC / DC converter and the DC / AC converter. The controller can control the operation of one or more discrete components (e.g., switches) in the AC / AC converter to control power extraction from the first motor, and can further control one or more discrete components (e.g., switches) in the AC / AC converter to control power delivery to the coupling motor.

[0022] Referring now to the drawings, wherein like numerals represent like elements throughout the several views, Figure 1 is a schematic diagram of an aerial vehicle 100 according to an exemplary embodiment of the present disclosure. Figure 1The exemplary aerial vehicle 100 is configured as an aircraft. The aircraft generally includes a fuselage 102 forming the main body of the vehicle 100, a first wing 104 extending from the port side of the vehicle, and a second wing 106 extending from the starboard side of the vehicle. The first wing 104 and the second wing 106 each extend laterally from the fuselage 102. The aircraft also includes a tail 108 having one or more stabilizers 110, and in particular includes a vertical stabilizer and a horizontal stabilizer. It will be understood that the aircraft can take the form of any suitable aerial vehicle, including but not limited to a rotary wing aircraft (e.g., a helicopter). The vehicle 100 also includes a propulsion system 112, which includes one or more propellers 114.

[0023] Now refer to Figure 2 , providing the ability to incorporate Figure 1 Schematic diagram of a propeller in an exemplary propulsion system 112 of a vehicle 100. More specifically, Figure 2 In the embodiment shown in FIG, the propulsor is configured as a gas turbine engine 120, more specifically, Figure 2 The gas turbine engine 120 is configured as a turbofan engine. The turbofan engine includes a fan 122 and a turbine 124 drive-coupled to the fan 122. The turbofan engine also includes an outer nacelle 126 that at least partially surrounds the fan 122 and the turbine 124. The turbine 124 of the illustrated embodiment may include a low-pressure (LP) compressor 128, a high-pressure (HP) compressor 129, a combustor 130, an HP turbine 131, and an LP turbine 132 arranged in series flow order. The fan 122, the LP compressor 128, and the LP turbine 132 are rotationally coupled via an LP shaft 134. The HP compressor 129 and the HP turbine 131 are rotationally coupled via an HP shaft 135. The fan 122, the LP compressor 128, and the LP turbine 132 are rotationally coupled via the LP shaft 134, commonly referred to as the LP spool of the gas turbine engine 120. The HP compressor 129 and the HP turbine 131 are rotationally coupled via the HP shaft 135, commonly referred to as the HP spool of the gas turbine engine 120. While the gas turbine engine 120 of the illustrated embodiment includes a core flow path for the working fluid through the HP spool and a bypass flow path for the working fluid generated by the fan 122 through the bypass flow path, in other embodiments, the gas turbine engine 120 may include additional working fluid flows, such as a so-called third flow. Additionally and / or alternatively, the gas turbine engine 120 may include an intermediate pressure (IP) spool having an IP compressor and an IP turbine (see, e.g., FIG. 1 ). Figure 11 , where an IP spool is shown having an IP compressor 206 and an IP turbine 208).

[0024] Now go to Figure 3, shows an embodiment of a gas turbine engine 120 that includes a power transmission system 137 for extracting mechanical power from one spool of the gas turbine engine and transmitting the mechanical power to another spool of the gas turbine engine via electromagnetic interaction, as will be discussed further below. The power transmission system 137 may include a first motor 136 that is rotationally coupled to a first pressure spool 138. In the illustrated embodiment, the first pressure spool 138 is an LP spool (e.g., the LP compressor 128, the LP turbine 132, and the LP spool 134). In other embodiments, the first pressure spool 138 may be an HP spool or an IP spool. When the first pressure spool 138 is in the form of an LP spool, the first pressure axis of the first pressure spool 138 corresponds to the LP spool 134. Similarly, when the first pressure spool 138 is in the form of an HP spool, the first pressure axis of the first pressure spool 138 corresponds to the HP spool 135. While the first electric machine 136 is depicted as being directly integrated into the LP shaft 134 and positioned radially inwardly in the working flow path of the fan 122 and / or the LP compressor 128, in some embodiments, an offtake shaft may be rotationally coupled to the LP shaft 134 and oriented radially to position the first electric machine 136 offset from the LP shaft 134. For example, the offtake shaft may be coupled at a first end via a gear arrangement (e.g., a bevel gear) and oriented radially to position the first electric machine 136 radially outwardly of the working flow path of the fan 122 and / or the LP compressor 128. In some embodiments, a clutch may be coupled between the first electric machine 136 and the LP shaft 134.

[0025] The electric machine 136 includes a first stator 140 having at least one first winding 142 and a first rotor 144 having at least one first permanent magnet 146. The first stator 140 may be fixed to the gas turbine engine 120 so that it remains stationary relative to the rotating LP shaft 134. When operating as a generator, the first rotor 144 is configured to rotate in response to the rotation of the LP shaft 134, wherein the relative rotation of the at least one first permanent magnet 146 induces a current in the at least one first winding 142 of the first electric machine 136 via electromagnetic interaction between the first stator 140 and the first rotor 144. When operating as a motor, energization of the at least one first winding 142 generates a magnetic field that interacts with the magnetic field of the at least one first permanent magnet 146. This interaction of the magnetic fields generates a force on the at least one first permanent magnet 146, which in turn generates a reaction force on the LP shaft 134. The LP shaft 134 can be accelerated by using the first electric machine 136 as a motor and can be decelerated by using the first electric machine 136 as a generator.

[0026] In the illustrated embodiment, the at least one first winding 142 of the first motor 136 includes three different and electrically separate first windings 142 to provide three-phase electrical power. The three different and electrically separate first windings 142 of the first stator 140 are electrically coupled to a first power line 148a, a first power line 148b, and a first power line 148c, respectively.

[0027] Due to the relative motion between the first rotor 144 and the first stator 140, the first electric machine 136 of the illustrated embodiment is configured to generate a first electric power, which is delivered to an alternating current / alternating current (AC / AC) converter 150. The AC / AC converter 150 is, in turn, configured to convert the first electric power into an output electric power and deliver the output electric power to the coupled electric machine 152. As will be appreciated, the AC / AC converter 150 can be configured to receive three-phase power (e.g., the first electric power) from the first electric machine 136 via the first power lines 148a, 148b, and 148c, convert the three-phase power into a three-phase output power (e.g., the output electric power) to provide to the coupled electric machine 152.

[0028] In one form, the AC / AC converter 150 may include an AC / DC converter 154 and a direct current / alternating current (DC / AC) converter 156 coupled together via a DC link capacitor 158. The AC / DC converter 154 is configured to receive AC power (e.g., a first electrical power) via first power lines 148a, 148b, and 148c and convert the AC power to DC power, which is provided to the DC / AC converter 156 via the DC link capacitor 158. One or more electrical loads associated with the operation of the aircraft 100 may receive the DC power 160. For example, electrical loads such as avionics, heaters, sensors, etc. may be powered directly by the DC power 160 or indirectly through an additional DC / AC converter (not shown).

[0029] The DC / AC converter 156 is configured to receive DC power via the DC link capacitor 158, convert the DC power into three-phase AC power, and provide three-phase power (e.g., output electric power) to the coupled motor 152 via output power lines 162a, 162b, and 162c. Each of the output power lines 162a, 162b, and 162c can be coupled to the coupled motor 152 via slip rings 164a, 164b, and 164c, respectively. The slip rings 164a, 164b, and 164c can take any suitable conductive form for transmitting electric power from the output power lines 162a, 162b, and 162c to the coupled motor 152.

[0030] Now go to Figure 4 , shows an embodiment of the coupled motor 152, which includes output power lines 162a, 162b, and 162c, which are electrically coupled to the coupled motor 152 via slip rings 164a, 164b, and 164c. Each of the coupled windings 170a, 170b, and 170c obtains electrical power from the output power lines 162a, 162b, and 162c via slip rings 164a, 164b, and 164c.

[0031] Back to Figure 3 The motor 152 is a dual-rotor motor that is rotationally coupled to both the first pressure spool 138 and the second pressure spool 166. In the illustrated embodiment, the second pressure spool 166 is an HP spool (e.g., the HP compressor 129, the HP turbine 131, and the HP shaft 135). In other embodiments, the second pressure spool 166 may be an LP spool or an IP spool. The coupled motor 152 includes a first coupled rotor 168 having at least one coupled winding 170 and a second coupled rotor 172 having at least one coupled permanent magnet 174. The first coupled rotor 168 is configured to rotate with the rotation of the LP shaft 134, while the second coupled rotor 172 is configured to rotate with the rotation of the HP shaft 135. When operating as an electric motor, electrical excitation of the at least one coupled winding 170 of the first coupled rotor 168 generates a magnetic field that interacts with the magnetic field of the at least one coupled permanent magnet 146 of the second coupled rotor 172. The electromagnetic interaction between first coupling rotor 168 and second coupling rotor 172 allows mechanical power to be transferred between LP shaft 134 and HP shaft 135. Activation of at least one coupling winding 170 can allow mechanical power to be transferred between LP shaft 134 and HP shaft 135 via the electromagnetic interaction of first coupling rotor 168. Depending on the nature of the energizing signal to at least one coupling winding 170, mechanical power can be transferred from LP shaft 134 to HP shaft 135 in one form and from HP shaft 135 to LP shaft 134 in another form. In the illustrated embodiment, it is contemplated that mechanical power is transferred from LP shaft 134 to HP shaft 135 via the electromagnetic interaction of first coupling rotor 168 and second coupling rotor 172.

[0032] When operating as a generator, rotation of at least one coupled permanent magnet 146 causes electrical excitation of at least one coupled winding 170 of first coupled rotor 168. Electromagnetic interaction between first coupled rotor 168 and second coupled rotor 172 allows mechanical power to be transferred between LP shaft 134 and HP shaft 135.

[0033] Figure 3The power transmission system 137 shown in FIG is capable of transmitting mechanical power including a first portion transmitted between the first pressure spool 138 and the second pressure spool 166 via electromagnetic interaction between the first coupling rotor 168 and the second coupling rotor 172, and a second portion transmitted between the first pressure spool 138 and the second pressure spool 166 via the AC / AC power converter 150. In one form, the first portion provided by the power transmission system 137 is 166 kW of power transmitted via the shaft-to-shaft interaction, while the second portion provided by the power transmission system 137 is 334 kW of power transmitted via the AC / AC converter 150, which is used to power at least one coupled winding 170.

[0034] Although the power transmission system 137 is shown as three-phase power from the first motor 136 being converted to three-phase power for the coupled motor 152 via the AC / AC converter 150, it should be understood that different forms of power are also contemplated, such as single-phase AC and other multi-phase AC power.

[0035] Figure 5 Show Figure 3 FIG1 is a power flow diagram of a power transmission system 137 in one form, wherein a first portion of the mechanical power provided by the power transmission system 137 is 166 kW of power transmitted via shaft-to-shaft interaction, and a second portion of the mechanical power provided by the power transmission system 137 is 334 kW of power transmitted via the AC / AC converter 150, which is used to power at least one coupled winding 170. Because only a portion of the power transmission occurs via the electrical power transmission from the first electric machine 136, the AC / DC converter 154, the DC / AC converter 156, and the coupled electric machine 152, the overall efficiency of the system is 91%. Other efficiencies (e.g., efficiencies in the range of 85%-95%) are also contemplated in other embodiments having different amounts of power transmission. Figure 5 The efficiency levels of the power transmission system 137 shown in exceed the efficiency of a system having a conventional electric machine on the LP shaft 134 and a conventional electric machine on the HP shaft 135 .

[0036] Turning now to FIG. 6 , a conventional prior art system includes a first electric machine 136 and a second electric machine 176 that rotate with the HP shaft 134. The second electric machine 176 includes a second stator 178 having at least one second winding 180 and a second rotor 182 having at least one second permanent magnet 184. The second stator 178 may be fixed to the gas turbine engine 120 so that it remains stationary relative to the rotating HP shaft 135. When operating as a generator, the second rotor 182 is configured to rotate in response to rotation of the HP shaft 135, wherein the relative rotation of the at least one second permanent magnet 184 induces a current in the at least one second winding 180 of the second electric machine 176 via electromagnetic interaction between the second stator 178 and the second rotor 182. When operating as a motor, energization of the at least one second winding 180 generates a magnetic field that interacts with the magnetic field of the at least one second permanent magnet 184. The interaction of the magnetic fields generates a force on the at least one second permanent magnet 184, which in turn generates a reaction force on the HP shaft 135. The HP shaft 135 may be accelerated by using the second electric machine 176 as a motor, and may be decelerated by using the second electric machine 176 as a generator.

[0037] As shown in FIG6 , when the first motor 136 is used as a motor, electric power can be delivered to the second motor 176 via the AC / AC converter 150 . Figure 3 The difference between the configurations of the power transmission system 137 is that in Figure 3 In FIG6 , the same power transfer of 500 kW can be divided between direct shaft-to-shaft transfer and transfer via the AC / AC converter 150, whereas FIG6 requires that all power be transferred through the AC / AC converter 150. Therefore, the AC / AC converter 150 of FIG6 must be constructed to handle a greater power throughput. In contrast, Figure 3 The configuration can be built with lower-power components, which can reduce weight and save costs.

[0038] Now go to Figure 7 , one embodiment of the first motor 136 is a field winding machine, wherein Figure 3 The permanent magnets are replaced by a field wound rotor 186 having at least one field winding 188 . Figure 7The power transmission system 137 also includes an excitation converter 190 for converting the AC power from the coupled windings 170 into power that can be used to drive the excitation windings 188. In one form, the excitation converter 190 can convert the AC power from the coupled windings 170 into DC power. In the illustrated embodiment, the excitation converter 190 can receive power from three wires associated with the three phases of the coupled motor 152 and provide power to the excitation wound rotor 186 via two wires. In one form, the two wires carry the DC power from the excitation converter 190 to at least one of the excitation windings 188.

[0039] Figure 8 Yet another embodiment of the power transmission system 137 is shown in which a gear arrangement 192 is integrated into the coupling motor 152 to convert a first rotational speed of the LP shaft 134 to a second rotational speed of the coupled windings 170 of the coupling motor 152. The gear arrangement 192 can take any suitable form to provide any suitable speed ratio between the LP shaft 134 and the coupled windings 170 of the coupling motor 152. In one form, the speed ratio is 2:1, such that the rotational speed of the LP shaft 134 is twice that of the coupled windings 170. In another form, the rotational speed ratio is 1:2, such that the rotational speed of the LP shaft 134 is half that of the coupled windings 170. The gear arrangement 192 can take any of a variety of gear arrangements, including an epicyclic gear arrangement (e.g., a planetary gear arrangement).

[0040] like Figure 8 As shown, continuing to use the same power transfer of 500kW from the LP shaft 134, adding the gearing 192 results in a shaft-to-shaft power transfer of 334kW, while the power provided to the coupled motor 152 via the AC / AC converter 150 is only 166kW. Therefore, the use of the gearing 192 can further reduce the total power passing through the AC / AC converter 150, which allows further use relative to the Figure 3 and the embodiment shown in FIG6 with lower power components.

[0041] above Figure 3 、 Figure 7 and Figure 8 The features of each embodiment can be compared with the above Figure 3 、 Figure 7 and Figure 8 The other features of each embodiment are combined. For example, Figure 7 The use of the field wound rotor 186 can be combined with Figure 8 The gear device 192 is combined with the gear device 192.

[0042] In addition, despite Figure 3 、 Figure 7 and Figure 8The various embodiments shown in FIGURE 1 depict coupled motor 152 receiving output power from AC / AC converter 150, but in some additional and / or alternative embodiments, coupled motor 152 may receive output power from other power sources. For example, coupled motor 152 may receive power from an energy storage device (e.g., a battery), which provides power to coupled motor 152 via a DC / AC converter, which together are similar to DC link capacitor 158 and DC / AC converter 156.

[0043] In yet other embodiments, the gas turbine engine 120 may include an electric motor (e.g., the first electric motor 136) coupled to additional and / or alternative shafts (e.g., an IP spool), and may include a coupled electric motor (e.g., the coupled electric motor 152) coupled to additional and / or alternative shafts other than those described in the embodiments shown herein. For example, the first electric motor 136 may be coupled to the HP spool instead of or in addition to the first electric motor 136 being coupled to the LP spool. Alternatively and / or in addition, the first electric motor 136 may be coupled to the IP spool.

[0044] In the embodiments of the power transmission system 137 described herein, power may be extracted from the LP shaft 134 by the first electric machine 136 and delivered to the HP shaft 135 through the AC / AC converter 150 and via the coupled electric machine 152. In further alternative and / or additional embodiments, power may be extracted from the HP shaft 135 by the coupled electric machine 152 and delivered to the LP shaft 134 through the AC / AC converter 150 and via the first electric machine 136. In view of the above description of alternative and / or additional embodiments, it should be appreciated that power may flow in any given direction using any type of electric machine coupled to any suitable shaft of the gas turbine engine and coupling electric machines between any two shafts.

[0045] Additionally, the power transmission system 137 may include a controller 194 for regulating the operation of the AC / AC converter 150 to facilitate conversion between AC power associated with the first electric machine 136 and AC power associated with the coupled electric machine 152. Thus, the controller 194 may be configured to operate discrete devices (e.g., switches) within one or more portions of the AC / AC converter 150 to facilitate conversion between the AC power. In some embodiments, the controller 194 may be integrated with an engine controller for regulating the operation of the gas turbine engine 120, while in other embodiments, the controller 194 may be a standalone controller separate from the engine controller. As will be appreciated, the engine controller may be a full authority digital engine controller (FADEC). The controller 194 may be configured to receive input from, for example, the engine controller or any other suitable input device (e.g., pilot commands) and operate in accordance with the input to regulate the operation of the AC / AC converter 150, the first electric machine 136, and the coupled electric machine 152. For example, if the engine controller is requested to rapidly accelerate the HP spool in response to a performance demand (e.g., a rapid change in input due to a pilot command, requiring a rapid change in core power from the HP spool), the engine controller may send a request to controller 194 to transfer power from the LP spool 134 to the HP spool 135. Upon receiving the input from the engine controller, controller 194 may adjust the operation of AC / AC converter 150 to extract power using first electric machine 136 and coupled electric machine 152 as described above. In another alternative and / or additional example, controller 194 may receive input from the engine controller to increase the operational margin of gas turbine engine 120, which requires power transfer from the LP spool 134 to the HP spool 135. In response to the operability demand, the engine controller may provide an input to controller 194 corresponding to the amount of margin to be increased, wherein controller 194 may determine the amount of power transfer corresponding to the amount of margin to be increased and command AC / AC converter 150 accordingly. Alternatively, the engine controller may provide an amount of power to be transferred between the LP spool 134 and the HP spool 135 , with the controller 194 adjusting operation of the AC / AC converter 150 to provide the requested power transfer.

[0046] Special References Figure 9, embodiments of the controller 194 will be described. In at least some embodiments, the controller 194 may include one or more computing devices 196. The computing devices 196 may include one or more processors 196A and one or more storage devices 196B. The one or more processors 196A may include any suitable processing device, such as a microprocessor, a microcontroller, an integrated circuit, a logic device, and / or other suitable processing device. The one or more storage devices 196B may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, a hard drive, a flash drive, and / or other storage devices.

[0047] One or more memory devices 196B may store information accessible to one or more processors 196A, including computer-readable instructions 196C executable by one or more processors 196A. Instructions 196C may be any set of instructions that, when executed by one or more processors 196A, cause one or more processors 196A to perform operations. In some embodiments, instructions 196C may be executed by one or more processors 196A to cause one or more processors 196A to perform operations, such as any operations and functions configured by controller 194 and / or computing device 196, operations for operating one or more aspects of power delivery system 137, and / or any other operations or functions of one or more computing devices 196. Instructions 196C may be software written in any suitable programming language or implemented in hardware. Additionally and / or alternatively, instructions 196C may be executed in logically and / or virtually independent threads on one or more processors 196A. One or more memory devices 196B may also store data 196D accessible to one or more processors 196A. For example, data 196D may include data indicative of inputs, data indicative of operation of AC / AC converter 150 , data indicative of power flow between LP shaft 134 and HP shaft 135 , data indicative of engine / aircraft operating conditions, and / or any other data and / or information described herein.

[0048] The computing device 196 may also include a network interface 196E for communicating with other components of the air vehicle 100, including the engine controller. The network interface 196E may include any suitable components for connecting to one or more networks, such as transmitters, receivers, ports, controllers, antennas, and / or other suitable components.

[0049] The technology discussed herein relates to computer-based systems, as well as actions taken by and information sent to computer-based systems. Those skilled in the art will recognize that the inherent flexibility of computer-based systems allows for a wide variety of possible configurations, combinations, and divisions of tasks and functions between components. For example, the processes discussed herein can be implemented using a single computing device or a combination of multiple computing devices. Databases, memory, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0050] Now refer to Figure 10 , it should be understood that the present disclosure may also provide a method 198 of operating the power transmission system 137. The method 198 may be used in conjunction with Figure 3 、 Figure 7 and Figure 8 In one exemplary aspect, the method 198 includes rotating the first pressure spool 138 of the gas turbine engine 120 at 200. The method 198 also includes rotating the first coupling rotor 168 of the coupling motor 152 as a result of rotating the first pressure spool 138 at 202, the coupling motor 152 having a second coupling rotor 172 that electromagnetically interacts with the first coupling rotor 168, the second coupling rotor 172 being mechanically coupled for rotation with the second pressure spool 166 of the gas turbine engine 120. The method 198 also includes transmitting mechanical power from the first pressure spool 138 of the gas turbine engine 120 to the second pressure spool 166 via electromagnetic interaction between the first coupling rotor 168 and the second coupling rotor 172 at 204.

[0051] Figure 10 The exemplary method 198 may also include generating electric power using a first electric machine 136 having a first rotor mechanically coupled for rotation with a first pressure shaft, wherein the first pressure shaft is the LP shaft 134 of the gas turbine engine 120. Figure 10 The exemplary method 198 may also include transmitting the first electrical power from the first motor 136 to the coupled motor 152 via the AC / AC converter 150. Additionally, Figure 10 The exemplary method 198 may also include wherein the first rotor 144 is a field wound rotor, and further includes powering the field wound rotor of the first electric machine 136 from the first coupled rotor 168. Additionally and / or alternatively, Figure 10 The exemplary method 198 may also include converting the first rotational speed of the first pressure spool 138 to a second rotational speed of the coupled winding 170 of the coupled motor 152 via the gear arrangement 192. Additionally and / or alternatively, Figure 10The exemplary method 198 may also include using an energy storage device to power the coupled motor 152. Additionally and / or alternatively, Figure 10 The exemplary method 198 may also include mechanically powering the first motor 136 using a discharge shaft mechanically coupled to the shaft of the first pressure spool 138. Additionally and / or alternatively, Figure 10 The exemplary method 198 may also include controlling the AC / AC converter 150 using the controller 194 in response to the pilot's request for a power change to the second pressure spool 166 .

[0052] As will be appreciated, transferring power between spools of gas turbine engine 120 is necessary for management of the engine cycle, such as operability and / or performance of gas turbine engine 120. The disclosed architecture and controls improve the efficiency and speed of transferring power between spools. Figure 3 、 Figure 7 and Figure 8 The embodiments further improve the efficiency and speed of transmitting power between spools.

[0053] Further aspects are provided by the subject matter of the following clauses:

[0054] A power transmission system, comprising: a first pressure spool of a gas turbine engine, the first pressure spool being configured to rotate and compress a working fluid to a first pressure; a second pressure spool of the gas turbine engine, the second pressure spool being configured to rotate and compress the working fluid to a second pressure different from the first pressure; and a coupling motor, the coupling motor being configured to transmit mechanical power between the first pressure spool and the second pressure spool, the coupling motor having: a first coupling rotor, the first coupling rotor being coupled to rotate with the first pressure spool; and a second coupling rotor, the second coupling rotor being coupled to rotate with the first pressure spool; wherein, during operation of the coupling motor, the first pressure spool is electromagnetically coupled to the second pressure spool via the coupling motor.

[0055] A power transmission system as described in the preceding clause, wherein the first pressure spool comprises a first motor.

[0056] A power transfer system as claimed in any preceding clause, wherein the coupled electric machine is configured to receive electric power from the first electric machine.

[0057] The power transmission system of any of the preceding clauses, further comprising an AC / AC power converter configured to transmit power between the first electric machine and the coupled electric machine.

[0058] The power transmission system of any of the preceding clauses, further comprising a slip ring configured to electrically couple the first coupling rotor to the AC / AC electrical converter.

[0059] A power transmission system as claimed in any preceding clause, wherein the gas turbine engine comprises a medium pressure spool.

[0060] A power transmission system as claimed in any preceding clause, wherein the first electric machine comprises a first rotor, the first rotor being a field wound rotor.

[0061] A power transmission system as claimed in any preceding clause, wherein the field wound rotor is electrically connected to the first coupled rotor.

[0062] The power transmission system of any of the preceding clauses, further comprising a power converter configured to receive current from the first coupled rotor and deliver the current to the field wound rotor.

[0063] The power transmission system according to any of the preceding clauses, further comprising a gear arrangement that rotationally couples the first pressure spool to the first coupling rotor, wherein the gear arrangement is configured to convert a first rotational speed of the first pressure spool to a second rotational speed of the coupling winding of the coupling motor.

[0064] A power transmission system according to any of the preceding clauses, wherein the AC / AC converter includes an AC / DC converter, the AC / DC converter is configured to receive AC power from the first electric machine, the AC / AC converter includes a DC / AC converter, the DC / AC converter is configured to receive DC power from the AC / DC converter and convert the DC power to AC power, and the AC / AC converter is further configured to provide the AC power to the coupled electric machine.

[0065] A power transmission system as claimed in any preceding clause, wherein the first motor comprises a first rotor configured to rotate with the first pressure spool, the first rotor being a permanent magnet.

[0066] A power transmission system as claimed in any preceding clause, wherein the first coupled rotor comprises a first winding.

[0067] A power transmission system as claimed in any preceding clause, wherein the second coupling rotor comprises permanent magnets.

[0068] A power transmission system as described in any of the preceding clauses, further comprising a motor controller.

[0069] The power transmission system according to any of the preceding clauses, further comprising an electrical switch having an operating configuration characterized by an open state and a closed state, the electrical switch being configured to be controlled by the motor controller, the open state defining a condition in which no electrical power is transmitted between the second coupled rotor and the second converter.

[0070] A power transmission system as claimed in any one of the preceding clauses, wherein the controller is configured to operate any one of the coupled electric machine, the first electric machine and the second electric machine individually.

[0071] The power transmission system of any of the preceding clauses, further comprising a power bus configured to receive electrical power from the first and second electric machines.

[0072] A gas turbine engine having a first pressure spool and a second pressure spool; and a dual-rotor motor having a first rotor and a second rotor, the first rotor being coupled to the first pressure spool to rotate together with the first pressure spool, the second rotor being coupled to the second pressure spool to rotate together with the second pressure spool, the dual-rotor motor being configured to transmit mechanical power between the first pressure spool and the second pressure spool via electromagnetic interaction between the first rotor and the second rotor.

[0073] A power transmission system includes: a first pressure spool of a gas turbine engine, the first pressure spool being configured to rotate and compress a working fluid to a first pressure; a second pressure spool of the gas turbine engine, the second pressure spool being configured to rotate and compress the working fluid to a second pressure different from the first pressure; and a coupling motor having a first coupling rotor and a second coupling rotor, the coupling motor being configured to transmit mechanical power between the first pressure spool and the second pressure spool via electromagnetic interaction between the first coupling rotor and the second coupling rotor.

[0074] The power transmission system of the preceding clause, wherein the first pressure spool comprises a first motor having a first stator and a first rotor.

[0075] A power transmission system as claimed in any preceding clause, wherein the first coupled rotor comprises windings electrically connected to windings of the first rotor.

[0076] The power transmission system of any of the preceding clauses, further comprising an AC / AC power converter configured to transmit power between the first electric machine and the coupled electric machine.

[0077] A power transmission system according to any of the preceding clauses, wherein the first turbine of the first pressure spool generates a first mechanical power, wherein the mechanical power transmitted between the first pressure spool and the second pressure spool via electromagnetic interaction between the first coupling rotor and the second coupling rotor is a first part of the first mechanical power, and wherein a second part of the first mechanical power is transmitted between the first pressure spool and the second pressure spool via the AC / AC electrical converter.

[0078] A power transmission system according to any of the preceding clauses, wherein the AC / AC converter includes an AC / DC converter, the AC / DC converter is configured to receive AC power from the first electric machine, the AC / AC converter includes a DC / AC converter, the DC / AC converter is configured to receive DC power from the AC / DC converter and convert the DC power to AC power, and the AC / AC converter is further configured to provide the AC power to the coupled electric machine.

[0079] A power transmission system as claimed in any preceding clause, wherein the first motor comprises a first rotor configured to rotate with a first pressure spool, the first rotor being a permanent magnet.

[0080] A power transmission system as claimed in any preceding clause, wherein the first coupled rotor comprises a first winding.

[0081] A power transmission system as claimed in any preceding clause, wherein the second coupling rotor comprises permanent magnets.

[0082] A power transmission system as described in any of the preceding clauses, further comprising a motor controller.

[0083] The power transmission system according to any of the preceding clauses, further comprising an electrical switch having an operating configuration characterized by an open state and a closed state, the electrical switch being configured to be controlled by the motor controller, the open state defining a condition in which no electrical power is transmitted between the second coupled rotor and the second converter.

[0084] A power transmission system as claimed in any one of the preceding clauses, wherein the controller is configured to operate any one of the coupled electric machine, the first electric machine and the second electric machine individually.

[0085] The power transmission system of any of the preceding clauses, further comprising a power bus configured to receive electrical power from the first and second electric machines.

[0086] A method of operating a power transmission system, the method comprising: rotating a first pressure spool of a gas turbine engine; as a result of rotating the first pressure spool, rotating a first coupling rotor of a coupling motor, the coupling motor having a second coupling rotor, the second coupling rotor electromagnetically interacting with the first coupling rotor, the second coupling rotor mechanically coupled to rotate together with a second pressure spool of the gas turbine engine; and transmitting mechanical power from the first pressure spool of the gas turbine engine to the second pressure spool via the electromagnetic interaction between the first coupling rotor and the second coupling rotor.

[0087] The method of the preceding clause, further comprising generating first electrical power using a first electric machine having a first rotor mechanically coupled for rotation with the first pressure spool, and wherein the first pressure spool is an LP spool of the gas turbine engine.

[0088] The method of any of the preceding clauses, further comprising transmitting the first electrical power from the first electric machine to the coupled electric machine via an AC / AC converter.

[0089] A method as in any of the preceding clauses, wherein the first rotor is a field wound rotor, and further comprising driving the field wound rotor of the first electric machine by the first coupled rotor.

[0090] The method of any of the preceding clauses, further comprising converting a first rotational speed of the first pressure spool to a second rotational speed of the coupled winding of the coupled motor via a gear arrangement.

[0091] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the present disclosure is defined by the claims, and may include other examples that 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 do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A power transmission system, characterized in that: The power transmission system comprises: a first pressure spool of the gas turbine engine, the first pressure spool being configured to rotate and compress a working fluid to a first pressure; a second pressure spool of the gas turbine engine, the second pressure spool being configured to rotate and compress the working fluid to a second pressure different from the first pressure; and a coupling motor configured to transmit mechanical power between the first pressure spool and the second pressure spool, the coupling motor having: a first coupling rotor coupled to rotate together with the first pressure spool; and a second coupling rotor coupled to rotate together with the first pressure spool; Wherein, during operation of the coupling motor, the first pressure bobbin is electromagnetically coupled to the second pressure bobbin via the coupling motor.

2. The power transmission system according to claim 1, characterized in that in, The first pressure spool includes a first motor.

3. The power transmission system according to claim 2, characterized in that in, The coupled electric machine is configured to receive electrical power from the first electric machine.

4. The power transmission system according to claim 2, wherein: Further included is an AC / AC power converter configured to transfer power between the first electric machine and the coupled electric machine.

5. The power transmission system according to claim 4, characterized in that: Further included is a slip ring configured to electrically couple the first coupling rotor to the AC / AC power converter.

6. The power transmission system according to claim 1, characterized in that in, The gas turbine engine includes an intermediate pressure spool.

7. The power transmission system according to claim 2, wherein: in, The first motor includes a first rotor, which is a field wound rotor.

8. The power transmission system according to claim 7, characterized in that: in, The excitation winding rotor is electrically connected to the first coupling rotor.

9. The power transmission system according to claim 8, characterized in that Further included is a power converter configured to receive current from the first coupled rotor and deliver the current to the field wound rotor.

10. The power transmission system according to claim 1, wherein: Further included is a gear arrangement rotationally coupling the first pressure spool to the first coupling rotor, wherein the gear arrangement is configured to convert a first rotational speed of the first pressure spool to a second rotational speed of the coupling winding of the coupling motor.

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