Abstract: An engine body may include a piston body comprising a piston chamber and a regenerator body comprising a regenerator conduit. An engine body may include a working-fluid heat exchanger body comprising a plurality of working-fluid pathways fluidly communicating between the piston chamber and the regenerator conduit. Additionally, or alternatively, an engine body may include a heater body comprising a plurality of heating fluid pathways and the plurality of working-fluid pathways. The heating fluid pathways may have a heat transfer relationship with the working fluid pathways. The working-fluid pathways may fluidly communicate between the piston chamber and the regenerator conduit. The engine body may include a monolithic body defined at least in part by the piston body, the regenerator body, and the working-fluid heat exchanger body, and/or defined at least in part by the piston body, the regenerator body, and the heater body.

Abstract: A hybrid-electric propulsion system is provided. In one example aspect, the hybrid-electric propulsion system includes a power converter and a propulsor. The propulsor includes a gas turbine engine having a shaft and one or more bearings supporting the shaft. The propulsor also includes an electric machine electrically coupled with the power converter. The electric machine includes a stator assembly and a rotor assembly. The rotor assembly has a rotor and a rotor connection assembly. The rotor connection assembly operatively couples the rotor with the shaft. The rotor connection assembly has an insulated joint for interrupting common mode electric current from flowing from the rotor of the electric machine to the shaft. A grounding device is included to electrically ground the shaft. The power converter includes an electromagnetic interference filter to reduce common mode voltage reaching the electric machine.

Abstract: A method of removing heat from an electrical machine located in a gas turbine engine at least partially inward of a core airflow path in a radial direction, the electrical machine comprising an outer electrical machine stator and an inner electrical machine rotor is provided. The method includes directing a liquid coolant radially inward past the outer electrical machine stator and toward an inner electrical machine rotor using a coolant passageway. The liquid coolant is directed onto and/or through one or both of the inner electrical machine rotor and a rotor support thereby removing heat from the inner electrical machine rotor.

Abstract: A high voltage electric machine and power distribution system including one or more of such electric machines are provided. In one aspect, a high voltage electric machine includes a stator, a rotor, and a housing encasing at least a portion of the stator and rotor. The stator is modularized into cascaded voltage stator modules. The stator modules are galvanically isolated from one another by intermodular separators. At least one intermodular separator is positioned between each adjacent pair of stator modules. The stator modules are also galvanically isolated from the housing by a housing separator. The housing separator is positioned between the stator modules and the housing. Each stator module has an associated set of windings that are wound only within their associated stator module.

Abstract: A stator core is provided that can define a plurality of core slots in a surface thereof. The core slots can extend between a first and a second end portion of the stator core. A winding can be housed in the core slots. The winding can define a channel through at least a portion thereof. A cooling system can be operably coupled with the channel and can be configured to move a cooling fluid through the channel. A turbulator can be positioned within the channel. The turbulator can be within a flowpath of the cooling fluid and can be integrally formed with the winding.

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 the stator support structure. An electrical machine shaft is coupled to an end of a shaft of the propulsion engine via an intermediate shaft member extending axially between the end of the shaft and the electrical machine shaft. A bearing support frame extends from the propulsion engine, the bearing support frame defining a bearing cavity in conjunction with the electrical machine shaft. Electrical machine bearings radially extend from the bearing support frame to rotatably contact the electrical machine shaft. A rotor attached to a rotor support structure attached to the electrical machine shaft. The rotor rotates in conjunction with the electrical machine shaft to exchange energy with the shaft of the propulsion engine.

Abstract: A gas turbine engine includes an electrical machine positioned at least partially inward of a core airflow path, the electrical machine including an electrical rotor component and an electrical stator component, a connecting member positioned between the electrical machine and a rotary member, a disconnection device that is positionable between a disengaged position, in which the disconnection device is disengaged from the connecting member, and an engaged position, in which the disconnection device is engaged with the connecting member, and a controller including a processor, where the processor receives a signal from the electrical machine indicative of a fault, and in response to receiving the signal from the electrical machine indicative of the fault, directs the disconnection device to move from the disengaged position to the engaged position.

Abstract: A method of removing heat from an electrical machine located in a gas turbine engine at least partially inward of a core airflow path in a radial direction, the electrical machine including an outer generator stator and an inner generator rotor is provided. The method includes directing cooling airflow radially through an airflow passageway to an enclosure at least partially defined by a thermal shield at least partially around the electrical machine. The cooling airflow is directed radially inward past the outer generator stator and toward the inner generator rotor using a cooling manifold thereby removing heat from the generator rotor.

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 energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

Abstract: A computer-implemented system and method for training a neural network with enforced monotonicity are disclosed. An example system includes at least one processor and memory in communication with said at least one processor, wherein the memory stores instructions for providing a data model representing a neural network for predicting an outcome based on input data, the instructions when executed at said at least one processor causes said system to: receive a feature data as input data; predict an outcome based on the input data using the neural network; compute a loss function based on the predicted outcome and an expected outcome associated with the input data, the loss function being dependent on a monotonicity penalty ? computed based on a set of training data including the feature data and on a set of random data; and update weights of the neural network based on the loss function.

Abstract: A method includes forming elongated magnetic flux carrier portions in magnetically conductive sheets by cutting elongated magnetic flux barriers including one or more relief features into the magnetically conductive sheets, such that the magnetic flux barriers are separated from each other in radial directions of the magnetically conductive sheets. The method includes inserting or forming non-magnetic posts into the magnetic flux barriers such that each of the non-magnetic posts is elongated in a different radial direction of the radial directions from a first magnetic flux carrier portion to a second magnetic flux carrier portion of the magnetic flux carrier portions on opposite sides of at least one magnetic flux barrier; and forming at least part of a rotor for an electric machine assembly using the magnetically conductive sheets having the magnetic flux carrier portions, the non-magnetic posts, and the magnetic flux barriers.

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: A stator core is provided that can define a plurality of core slots in a surface thereof. The core slots can extend between a first and a second end portion of the stator core. A winding can be housed in the core slots. The winding can define a channel through at least a portion thereof. A cooling system can be operably coupled with the channel and can be configured to move a cooling fluid through the channel. A turbulator can be positioned within the channel. The turbulator can be within a flowpath of the cooling fluid and can be integrally formed with the winding.

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 the stator support structure. An electrical machine shaft is coupled to an end of a shaft of the propulsion engine via an intermediate shaft member extending axially between the end of the shaft and the electrical machine shaft. A bearing support frame extends from the propulsion engine, the bearing support frame defining a bearing cavity in conjunction with the electrical machine shaft. Electrical machine bearings radially extend from the bearing support frame to rotatably contact the electrical machine shaft. A rotor attached to a rotor support structure attached to the electrical machine shaft. The rotor rotates in conjunction with the electrical machine shaft to exchange energy with the shaft of the propulsion engine.

Abstract: An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

Abstract: A method of making a component of an electrical machine is provided. An additive manufacturing process is used to manufacture a part, including applying beams of energy to a successive plurality of ferromagnetic material particles and fusing them together to form a ring or segment of a ring with an axis, a solid portion, and laminas that extend from the solid portion in a radial or axial direction.

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: A three-stream gas turbine engine with an embedded electric machine and methods of operating the same are disclosed. In one aspect, a three-stream engine includes an electric machine operatively coupled with a shaft of the engine. The three-stream engine also includes a core engine and a primary fan and a mid-fan positioned upstream of the core engine. The primary fan and the mid-fan are operatively coupled with the shaft. During operation, the three-stream engine defines a tip speed ratio being defined by a tip speed of a rotor of the electric machine to a tip speed of a mid-fan blade of the mid-fan. The tip speed ratio is defined as being equal to or greater than 0.2 and less than or equal to 1.0.

Abstract: A hybrid-electric propulsion system is provided. In one example aspect, the hybrid-electric propulsion system includes a power converter and a propulsor. The propulsor includes a gas turbine engine having a shaft and one or more bearings supporting the shaft. The propulsor also includes an electric machine electrically coupled with the power converter. The electric machine includes a stator assembly and a rotor assembly. The rotor assembly has a rotor and a rotor connection assembly. The rotor connection assembly operatively couples the rotor with the shaft. The rotor connection assembly has an insulated joint for interrupting common mode electric current from flowing from the rotor of the electric machine to the shaft. A grounding device is included to electrically ground the shaft. The power converter includes an electromagnetic interference filter to reduce common mode voltage reaching the electric machine.