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

Abstract: An electrical machine includes a stator assembly coupled to an engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component and a stator disposed on a supporting surface of the stator support structure. The electrical machine also includes a rotor assembly including a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator. The rotor exchanges rotational energy with the shaft to operate as either an electrical motor or an electrical generator.

Abstract: A turbomachine equipped with an embedded electric machine having a segmented and movable stator is provided. In one aspect, a turbomachine defines a radial direction and includes a rotating component, actuators, and an electric machine. The electric machine includes a rotor assembly rotatable with and operatively coupled with the rotating component. The electric machine also includes a stator assembly having a stator split into stator segments. Each one of the stator segments is movable by one of the actuators between a first position and a second position along the radial direction, the stator segments each being closer to the rotor assembly along the radial direction when in the first position than when in the second position.

Abstract: A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

Abstract: A turbine engine that includes an engine core, a core casing surrounding the engine core, at least one cowl surrounding the core casing, a power converter located between the at least one cowl and the core casing, an electrical generator disposed within the engine core, at least one electrical strut having an outer wall defining an interior and extending radially between the engine core and the core casing; and at least one electrical conduit located within the interior and electrically coupling the generator to the power converter.

Abstract: A power system including a power converter system and an electric machine is provided. In one aspect, the power converter system has first and second switching elements. The electric machine includes a first multiphase winding electrically coupled with the first switching elements and a second multiphase winding electrically coupled with the second switching elements. The first and second multiphase windings are arranged and configured to operate electrically opposite in phase with respect to one another. One or more processors control the first switching elements to generate first pulse width modulated (PWM) signals based on received voltage commands to render a first common mode signal and also control the second switching elements to generate second PWM signals based on received voltage commands to render a second common mode signal. The rendered first and second common mode signals have the same or similar waveform with opposite polarity with respect to one another.

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

Abstract: An electric machine is provided. The electric machine defines a centerline and includes: a stator assembly; a rotor assembly rotatable relative to the stator assembly about the centerline; and an actuator coupled to the rotor assembly, the stator assembly, or both for moving the rotor assembly, the stator assembly, or both along the centerline between a first position and a second position, the rotor assembly positioned closer to the stator assembly when in the first position than when in the second position.

Abstract: An airgap cooling system (140) for an electric machine (100), the electric machine (100) including a rotor assembly (102) rotatably mounted within a stator assembly (120) and defining an airgap (130) therebetween, wherein the stator assembly (120) comprises a lamination stack (124). The airgap cooling system (140) includes a plurality of distribution passages (142) that extend through the lamination stack (124); a plurality of discharge passages (150) that extend between the plurality of distribution passages (142) and the airgap (130); a cooling manifold (160) defining an annular distribution plenum (164) in fluid communication with the plurality of distribution passages (142), wherein the cooling manifold (160) is configured for receiving a cooling fluid (144) and directing the cooling fluid (144) into the distribution plenum (164), through the distribution passage (142) and the discharge passage (150), and into the airgap (130).

Abstract: A method for preparing a trained complete selective classifier can be applied to a trained complete selective classifier having an existing trained selection mechanism. The trained selective classifier is modified to disregard the existing trained selection mechanism and use, as a basis for an alternate selection mechanism, at least one classification prediction value, for example the predictive entropy or the maximum predictive class logit. Optionally, before modifying the trained selective classifier, the method commences with an untrained selective classifier, which may be trained with a modified loss function to obtain the trained selective classifier. The modified loss function has at least one added term, relative to an original loss function, and the at least one added term decreases entropy.

Abstract: A generator assembly includes a stator assembly coupled to an engine stator component of a propulsion engine, the stator assembly including: a stator support structure fixedly attached to the engine stator component; a stator disposed on a supporting surface of the stator support; a manifold coupled to the stator support, the manifold defining a connection volume and including at least one coolant opening at a connection end of the manifold; and an electrical connector extending between the stator and a connection device disposed on the connection end. The generator assembly also includes a rotor assembly comprising a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure, wherein the rotor rotates in conjunction with the shaft to generate a power signal that travels through the electrical connector to the connection device.

Abstract: An electric power system for a vehicle includes at least one electric machine, one or more power rectifiers, and a plurality of DC channels. The at least one electric machine includes a plurality of tooth-wound multi-phase windings that are substantially magnetically decoupled, and the at least one electric machine is mechanically balanced even if one of the plurality of windings is de-energized. The one or more power rectifiers are configured to produce rectified power from the power generated by the at least one electric machine. The plurality of DC channels are formed after the at least one power rectifier and are configured to provide DC power to one or more loads within a vehicle.

Abstract: A vehicle includes a gas turbine engine having at least two spools and an associated power system. The power system includes two independent power subsystems, including a first power subsystem for managing power transfer between spools and a second power subsystem for supplying a base power load to the vehicle. The first power subsystem has a first electric machine mechanically coupled with a first spool of the gas turbine engine and a second electric machine mechanically coupled with a second spool. The second electric machine is electrically coupled with the first electric machine such that electrical power is transmittable therebetween. The second power subsystem has a third electric machine mechanically coupled with one of the spools. The third electric machine is electrically coupled with a load positioned offboard the gas turbine engine. The first power subsystem and the second power subsystem are electrically decoupled from one another.

Abstract: A vehicle includes a gas turbine engine having at least two spools and an associated power system. The power system includes two independent power subsystems, including a first power subsystem for managing power transfer between spools and a second power subsystem for supplying a base power load to the vehicle. The first power subsystem has a first electric machine mechanically coupled with a first spool of the gas turbine engine and a second electric machine mechanically coupled with a second spool. The second electric machine is electrically coupled with the first electric machine such that electrical power is transmittable therebetween. The second power subsystem has a third electric machine mechanically coupled with one of the spools. The third electric machine is electrically coupled with a load positioned offboard the gas turbine engine. The first power subsystem and the second power subsystem are electrically decoupled from one another.

Abstract: An electric machine can include a stator core having a plurality of core teeth that define a plurality of core slots in a surface thereof. A winding can be housed at least partially in the core slots. The winding can include a tube defining a channel through at least a portion thereof and one or more wires disposed along a surface of the tube that is opposite the channel. A cooling system can be operably coupled with the channel and configured to move a cooling fluid through the channel.

Abstract: A propulsor is provided including a gas turbine engine having a shaft and one or more bearings supporting the shaft, a rotor hub operatively coupled to the shaft and comprising a hub flange, an electric machine comprising a stator assembly and a rotor assembly, a rotor connection member operatively coupled to the rotor assembly of the electric machine and comprising a connection flange, and an insulated joint for operatively coupling the rotor assembly with the shaft. The insulated joint includes a plurality of insulative layers, at least one of the plurality of insulative layers extending between the hub flange and the connection flange to interrupt common mode electric current from flowing between the rotor assembly and the shaft.

Abstract: An electric machine having an electrically insulative manifold is disclosed. In one example aspect, an electric machine includes a non-electrically conductive manifold. The manifold defines a chamber operable to receive a cooling fluid. The electric machine includes a prime winding in fluid communication with the chamber and one or more secondary windings in electrical communication with the prime winding and in fluid communication with the chamber. Further, the electric machine includes an electric machine terminal extending through the non-electrically conductive manifold and coupled with the prime winding. The electric machine terminal can provide or collect cooling fluid from the chamber of the manifold and can act as the electrical connection point for directing electrical power to or from the windings of the electric machine.

Abstract: A turbomachine is provided. In one aspect, the turbomachine includes a rotating component and an electric machine that includes a stator assembly and a rotor assembly rotatable with the rotating component relative to the stator assembly. Further, the turbomachine includes an actuator coupled with the rotor assembly, the stator assembly, or both for moving the rotor assembly, the stator assembly, or both relative to one another. In addition, the turbomachine includes a controller configured to receive data indicating an operating state of the rotating component and cause the actuator to adjust a position of at least one of the stator assembly and the rotor assembly based at least in part on the operating state of the rotating component.

Abstract: A power system including a power converter system and an electric machine is provided. In one aspect, the power converter system has first and second switching elements. The electric machine includes a first multiphase winding electrically coupled with the first switching elements and a second multiphase winding electrically coupled with the second switching elements. The first and second multiphase windings are arranged and configured to operate electrically opposite in phase with respect to one another. One or more processors control the first switching elements to generate first pulse width modulated (PWM) signals based on received voltage commands to render a first common mode signal and also control the second switching elements to generate second PWM signals based on received voltage commands to render a second common mode signal. The rendered first and second common mode signals have the same or similar waveform with opposite polarity with respect to one another.

Abstract: A generator assembly includes a stator assembly coupled to an engine stator component of a propulsion engine, the stator assembly including: a stator support structure fixedly attached to the engine stator component; a stator disposed on a supporting surface of the stator support; a manifold coupled to the stator support, the manifold defining a connection volume and including at least one coolant opening at a connection end of the manifold; and an electrical connector extending between the stator and a connection device disposed on the connection end. The generator assembly also includes a rotor assembly comprising a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure, wherein the rotor rotates in conjunction with the shaft to generate a power signal that travels through the electrical connector to the connection device.