Abstract: An example system comprises an electric machine including a stator and a rotor, a cooling system configured to supply a cooling fluid to cool the electric machine, and a stator tube configured to contain the cooling fluid within a stator portion of the electric machine and prevent the cooling fluid from contacting the rotor.

Abstract: A thermal management system for an energy storage system for an aircraft includes a pump circulating a thermal management fluid through the thermal management system and an energy storage device of the aircraft. A controller circuitry may control a variable pumping capacity of the pump based on sensing pressure or temperature of the thermal management fluid at the energy storage device. The controller circuitry may default operation of the pump to a first pumping capacity in response to the pressure or temperature being within a predetermined operating range and a predetermined failure condition or a power demand of an aircraft engine supply bus exceeding a predetermined threshold. The controller controlling operation of the pump to a second pumping capacity in response to absence of the power demand signal of the aircraft engine supply bus and the pressure or temperature being within the predetermined operating range.

Abstract: An example system includes a throttle control for managing power in a hybrid propulsion system that includes an electrical propulsion unit configured to operate using electrical energy sourced from an electrical energy storage system (ESS) and/or one or more electrical generators, the throttle control comprising: a control lever movable through a plurality of positions, the plurality of positions including: a regeneration position; an off position; a maximum electric only position; a maximum continuous dual source position; and a maximum non-continuous dual source position.

Abstract: Methods of controlling an in-line heater for an energy storage device are provided. A determination is made that a pump is running. When running, the pump circulates a thermal management fluid through a thermal management conditioning loop, which includes the in-line heater and a heat transfer hardware configured to transfer heat between the thermal management fluid and the energy storage device, wherein the in-line heater is in thermal communication with the thermal management fluid. The in-line heater is turned on in response to the determination that the pump is running and a temperature of the thermal management fluid is below a lower control limit.

Abstract: A thermal management system for an energy storage system, the energy storage system comprising an energy storage device, an energy storage monitoring system including circuitry dedicated and configured to monitor a temperature of the energy storage device. The thermal management system comprises: a thermal management conditioning loop, a pump configured to circulate a thermal management fluid through the thermal management conditioning loop, a heat source, and a heat transfer hardware in thermal communication with the energy storage device. An energy storage controller of the energy storage monitoring system is configured to confirm that a temperature of the thermal management fluid and/or a temperature of the energy storage device is below an upper safety limit, between a lower control limit and an upper control limit, or both, and in response, to send an enable heater request indicating the heat source is to turn on.

Abstract: An example hybrid aircraft propulsion system includes one or more power units configured to output electrical energy onto one or more electrical busses; a plurality of propulsors; and a plurality of electrical machines, each respective electrical machine configured to drive a respective propulsor of the plurality of propulsors using electrical energy received from at least one of the one or more electrical busses.

Abstract: In some examples, a system includes a bus and a first power converter connected to the bus. The system also includes a second power converter connected to the bus, the second power converter having a topology different from the topology of the first power converter. The system further includes a power source and an energy storage device connected to the bus via the first and second power converters, respectively. In addition, the system includes a source controller configured to control the first power converter and a storage controller configured to control the second power converter. The system also includes a system controller configured to determine a first set point for the first power converter, transmit an indication of the first set point to the source controller, determine a second set point for the second power converter, and transmit an indication of the second set point to the storage controller.

Abstract: In some examples, a system includes a load configured to generate propulsion based on power received from a bus via a power converter. The system also includes a controller configured to determine that a voltage magnitude on the bus is not less than a threshold level in a first instance and cause the power converter to deliver a first magnitude of power to the load in response to determining that the voltage magnitude is not less than the threshold level in the first instance. The controller is also configured to determine that the voltage magnitude on the bus is less than the threshold level in a second instance and cause the power converter to deliver a second magnitude of power to the load in response to determining that the voltage magnitude is less than the threshold level in the second instance, the second magnitude being less than the first magnitude.

Abstract: In some examples, a system includes an energy storage device configured to deliver power to a bus or receive power from a bus via a power converter. The system also includes a controller configured to determine that a voltage magnitude on the bus is less than a first threshold level in a first instance and cause the energy storage device to deliver power to the bus in response to determining that the voltage magnitude is less than the first threshold level. The controller is also configured to determine that the voltage magnitude on the bus is greater than a second threshold level in the second instance, wherein the second threshold level is greater than a first threshold level and cause the energy storage device to receive power from the bus in response to determining that the voltage magnitude is greater than the second threshold level.

Abstract: An example hybrid aircraft propulsion system includes one or more power units configured to output electrical energy onto one or more electrical busses; a plurality of propulsors; and a plurality of electrical machines, each respective electrical machine configured to drive a respective propulsor of the plurality of propulsors using electrical energy received from at least one of the one or more electrical busses.

Abstract: An example system includes a throttle control for managing power in a hybrid propulsion system that includes an electrical propulsion unit configured to operate using electrical energy sourced from an electrical energy storage system (ESS) and/or one or more electrical generators, the throttle control comprising: a control lever movable through a plurality of positions, the plurality of positions including: a regeneration position; an off position; a maximum electric only position; a maximum continuous dual source position; and a maximum non-continuous dual source position.

Abstract: In some examples, a system includes a load configured to generate propulsion based on power received from a bus via a power converter. The system also includes a controller configured to determine that a voltage magnitude on the bus is not less than a threshold level in a first instance and cause the power converter to deliver a first magnitude of power to the load in response to determining that the voltage magnitude is not less than the threshold level in the first instance. The controller is also configured to determine that the voltage magnitude on the bus is less than the threshold level in a second instance and cause the power converter to deliver a second magnitude of power to the load in response to determining that the voltage magnitude is less than the threshold level in the second instance, the second magnitude being less than the first magnitude.

Abstract: In some examples, a system includes a bus and a first power converter connected to the bus. The system also includes a second power converter connected to the bus, the second power converter having a topology different from the topology of the first power converter. The system further includes a power source and an energy storage device connected to the bus via the first and second power converters, respectively. In addition, the system includes a source controller configured to control the first power converter and a storage controller configured to control the second power converter. The system also includes a system controller configured to determine a first set point for the first power converter, transmit an indication of the first set point to the source controller, determine a second set point for the second power converter, and transmit an indication of the second set point to the storage controller.

Abstract: In some examples, a system includes an energy storage device configured to deliver power to a bus or receive power from a bus via a power converter. The system also includes a controller configured to determine that a voltage magnitude on the bus is less than a first threshold level in a first instance and cause the energy storage device to deliver power to the bus in response to determining that the voltage magnitude is less than the first threshold level. The controller is also configured to determine that the voltage magnitude on the bus is greater than a second threshold level in the second instance, wherein the second threshold level is greater than a first threshold level and cause the energy storage device to receive power from the bus in response to determining that the voltage magnitude is greater than the second threshold level.

Abstract: An example hybrid aircraft propulsion system includes one or more power units configured to output electrical energy onto one or more electrical busses; a plurality of propulsors; and a plurality of electrical machines, each respective electrical machine configured to drive a respective propulsor of the plurality of propulsors using electrical energy received from at least one of the one or more electrical busses.

Abstract: An example system comprises an electric machine including a stator and a rotor, a cooling system configured to supply a cooling fluid to cool the electric machine, and a stator tube configured to contain the cooling fluid within a stator portion of the electric machine and prevent the cooling fluid from contacting the rotor.

Abstract: An example hybrid aircraft propulsion system includes one or more parallel propulsion units, each of the parallel propulsion units comprising: a first propulsor; a gas turbine engine configured to drive the first propulsor; and an electrical machine selectively configurable to: generate, for output via one or more electrical busses, electrical energy using mechanical energy derived from the first propulsor or the gas turbine engine; and drive the first propulsor using electrical energy received via the one or more electrical busses; and one or more series propulsion units, each of the series propulsion units comprising: a second propulsor; and an electrical machine selectively configurable to: generate, for output via the one or more electrical busses, electrical energy using mechanical energy derived from the second propulsor or the gas turbine engine; and drive the second propulsor using electrical energy received from one or more electrical busses.

Abstract: An example hybrid aircraft propulsion system includes a plurality of electrical busses comprising a propulsion bus, a critical bus, and a non-critical bus; an electrical energy storage system coupled to each of the plurality of electrical busses; one or more power units configured to generate and output electrical energy via the propulsion bus; one or more electrical machines configured to drive respective propulsors using electrical energy received via the propulsion bus; one or more hotel loads configured to receive energy via the non-critical bus; and one or more critical loads configured to receive energy via the critical bus.

Abstract: A method for operation of a hybrid propulsion system is provided that includes providing a hybrid propulsion system including a gas turbine engine, an electrical system, and a controller configured to cause the gas turbine engine to produce a first mechanical power output and to cause the electrical system to produce a second mechanical power output. The method further includes causing the gas turbine engine to produce the first mechanical power output and causing the electrical system to produce the second mechanical power output, which causes a drive shaft of the gas turbine engine to rotate. The method further includes decreasing production of the first mechanical power output when a combination of the first mechanical power output and the second mechanical power output for take-off or climb is a predetermined percentage of a predetermined parameter of the gas turbine engine.

Abstract: Energy storage systems for aircraft and methods of operating the same are provided. The energy storage system may include a main battery, a propulsion power bus, a non-critical bus, a critical bus, and an engine starter bus. The propulsion power bus may be configured to convey electricity, which is supplied by the main battery, to an electric propulsion machine configured to provide propulsion for the aircraft. The non-critical bus may be configured to convey electricity to a hotel load on the aircraft. The critical bus may be configured to convey electricity, which is supplied by the main battery, to a critical load on the aircraft. The engine starter bus may be configured to convey electricity, which is supplied by the main battery, to an electric starter for a gas turbine engine, where the gas turbine engine is configured to power the electric propulsion machine.