Patent Description:
Vehicles, such as aircraft, are increasingly challenged to improve operating efficiency, reduce fuel consumption, and reduce or eliminate emissions. Aircraft are particularly challenged with increasing electrification to drive various aircraft systems and sub-systems. Utilizing hybrid-electric power systems by extracting power from propulsion systems to provide electric energy to drive an electrically-driven device may provide one or more such benefits. However, the inventors of the present disclosure have found that changes in load demand and energy output may adversely affect operation of the propulsion system or the electrically-driven devices, such as to lead into over-voltage, overspeed, or other undesired over-load conditions.

Furthermore, vehicles such as aircraft are limited with regard to a quantity of communicative couplings, sensing, and measurement between various components of the hybrid-electric power system. For instance, increased communicative couplings require increased communications channels, increased memory and storage, and increased processing, which may adversely increase vehicle complexity, performance, cost, and operability.

As such, there is a need for improved systems and methods for controlling hybrid-electric power systems.

<CIT> relates to a hybrid propulsion system for a multi-rotor rotary-wing aircraft, comprising: an internal combustion engine, an electric machine coupled to the internal combustion engine, a rectifier connected to the electric machine, conversion means, an electric network connecting the rectifier to the conversion means, electric motors connected to the conversion means, rotary-blade assemblies coupled to the electric motors, the system being characterized in that it comprises: detection means configured to detect a reduction in a demand for electrical power within the system to below a predetermined value, bypass means configured to bypass the electric machine when the detection means detects a reduction in the demand for electrical power.

<CIT> relates to a propulsion system for a multirotor aircraft, the propulsion system comprising: at least one power generation module configured to provide a first source of electrical power to one or more propulsion assemblies of the multirotor aircraft; a control system which is configured to determine the required electrical power demand of the propulsion assembly and calculate a predicted electrical power demand for a following period of time; wherein the control system is configured to alter the electrical power produced by the power generation module such as to produce a power envelope which comprises the electrical power produced by the power generation module corresponding to the predicted electrical power demand; wherein the control system is configured to determine if the power envelope meets the required electrical power demand; and wherein when the power envelope is less than the required electrical power demand the control system is configured to selectively connect a second source of electrical power for supplying power to the propulsion assembly such as to compensate for the difference between the power envelope and the required electrical power demand.

<CIT> relates to a hybrid aircraft propulsion system including 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.

Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims.

Additionally, the terms "low," "high," or their respective comparative degrees (e.g., lower, higher, where applicable) each refer to relative speeds within an engine, unless otherwise specified. For example, a "low-pressure turbine" operates at a pressure generally lower than a "high-pressure turbine. " Alternatively, unless otherwise specified, the aforementioned terms may be understood in their superlative degree. For example, a "low-pressure turbine" may refer to the lowest maximum pressure turbine within a turbine section, and a "high-pressure turbine" may refer to the highest maximum pressure turbine within the turbine section.

Embodiments of a vehicle, an electric bus system, and methods for operation are provided. Embodiments of the methods and systems depicted and described herein provide for control and operation of power distribution system, such as a hybrid-electric power system. Embodiments of the system and method provided herein may mitigate or eliminate over-load conditions, or furthermore limit communicative couplings between components of a hybrid-electric power system, allowing for improved efficiency and reduced complexity. In a particular embodiment, the system includes a vehicle, such as an aircraft having an engine, such as a propulsion system, or particularly a gas turbine engine propulsion system. An electric machine, such as a generator or motor-generator system, is operably connected to the engine to extract power and distribute electric power to a load device. Various embodiments of the load device may be an electrically-driven device, such as a thrust-generating system (e.g., an electrically-driven propulsion system, a boundary layer ingestion (BLI) fan, a rotary wing device, a lift or tilt-rotor system, etc.), pumps, compressors, thermal systems (e.g., environmental control system (ECS)), thermal management system (TMS), heating elements (e.g., anti-icing systems), radars, LIDARs, avionics, communications devices, directed-energy systems, electric motors, or other electrical systems at the vehicle.

Systems and methods provided herein include a computing system operably coupled to control the engine and the electric machine. The computing system is configured to execute operations that command the engine to generate torque, and for the electric machine to extract torque from the engine. The computing system may include schedules, graphs, charts, look-up tables, curves, or other predetermined settings for operating the engine within operability, performance, health, and/or safety limits of the engine. Predetermined settings may further include engine limits, or particularly all desired engine limits, within which the commanded torque extraction is limited to. The load device, such as an electric propulsion engine or electric motor separate from the engine, receives electric power provided from the electric machine via an electric bus.

A first power electronics device, such as a first inverter at the electric machine, controls torque extraction from the engine. The computing system controls torque extraction by the electric machine, such as by decreasing, increasing, or maintaining torque extraction, and further limits power output to the load device to prevent over-voltage at the electric bus. The computing system provides control commands to the engine and the first power electronics device to maintain bus voltage at desired levels, such as within voltage limits. Accordingly, the amount of torque extracted from the engine to generate power to the load device is controlled by the computing system. The first power electronics device, or the computing system configured to send and receive control commands to the first power electronics device, is configured in a power or torque control mode. The first power electronics device communicates with the computing system to exchange operating parameters, such as total power drawn, bus voltage, current, etc. As such, the amount of torque extracted by the electric machine, and subsequently the amount of power output to the load device, is regulated by the computing system and first power electronics device to keep the engine within desired operating limits. During operation of the system and execution of the method, the engine is controlled by the computing system (e.g., a FADEC or other engine controller) in accordance with operating parameters and operating limits at the engine, such as, but not limited to, stall margin, surge margin, rotor speed, temperature (e.g., exhaust gas temperature), torque output, thrust output, pressure ratio, or associated minimum and maximum limits relative thereto, or any other operability limit, performance limit, health/safety limit, or any other appropriate control limit of the engine.

An electric bus operably couples the first power electronics device to a second power electronics device, such as a second inverter operably coupled to the load device(s). The second power electronics device is configured in a voltage control mode to control power received at the load device(s). Accordingly, during operation of the system and execution of the method, the second power electronics device controls the load device relative to predetermined operating limits associated with the load device. When the second power electronics device approaches or exceeds the operating limits, the power received at the load device is limited. The load device operating limit may correspond to an electric propulsion engine rotational speed limit, stall margin at the electric propulsion engine, surge margin at the electric propulsion engine, a power output limit at the load device, a temperature limit at the load device, a flow limit at the load device, or any other operability, performance, health, or safety limit at the load device(s). Additionally, or alternatively, the second power electronics device may control the load device relative to voltage associated with the electric bus, such as a voltage limit of the electric bus. When the electric bus approaches or exceeds the voltage limit, the power received at the load device may be modified to reduce a voltage within the electric bus.

In an exemplary embodiment of operation, the computing system commands the engine to operate, such as to generate torque to be extracted by the electric machine to generate output power to the load device. Operation of the engine may be performed in accordance with a predetermined setting, schedule, chart, graph, table, etc. In a particular embodiment, operation of the engine includes generating and providing output power to the load device in accordance with the predetermined setting, schedule, chart, graph, table, etc. The computing system commands the first power electronics device and electric machine to extract torque from the engine and output power to the load device through the bus connecting the first power electronics device to the second power electronics device. The second power electronics device receives power from the first power electronics device and provides the output power to the load device(s). The second power electronics device allows the load device(s) to receive power through the bus until the load device(s) have reached a desired operating mode (e.g., a rated speed, rotational speed, flow rate, power or thrust output, temperature, pressure, pressure ratio, etc. at the load device). The second power electronics device limits the amount of power provided to the load device(s) in accordance with the load device operating limit (and additionally or alternatively, the electric bus voltage). In various embodiments, the second power electronics device includes a predetermined setting, schedule, function, graph, chart, table, etc. corresponding to the voltage limit.

During operation, the second power electronics device will limit the power output in accordance with the load device operating limit. For instance, the second power electronics device may limit current to the load device when the load device is at or above the load device operating limit. In an embodiment in which the load device is an electric propulsion engine, the load device operating limit may correspond to an electric propulsion engine rotational speed limit, a flow limit, a temperature limit, a power output limit, or other limit associated with the electric propulsion engine. Accordingly, the second power electronics device implements overlimit protection by reducing allowable torque at the load device when approaching an overlimit zone. As the power output to the load device is limited by the second power electronics device, the first electronics device senses, measures, or otherwise detects an increase in voltage at the electric bus. The first power electronics device commands, controls, or otherwise modulates the electric machine to decrease the amount of torque or electric power extracted from the engine to maintain the voltage at the electric bus within the voltage limit. Accordingly, the decreased torque extraction decreases the power output from the electric machine to the load device, and furthermore modulates the bus voltage to return or remain within the voltage limit. As such, the system and method allow for the engine and electric machine to command or "push" electric power to the load device rather than the load device commanding or "pulling" power from the engine and electric machine. Such embodiments allow for the engine and electric machine to operate based on operability, performance, health, and/or safety limits of the engine, while mitigating conflict, fluctuation, or disturbance as may be caused by load devices commanding power requirements that may adversely affect one or more limits at the engine.

Systems and methods provided herein allow for power distribution to one or more load devices without requiring communicative coupling between the engines or electric machines. If a first electric machine at a first engine at the vehicle fails then a second electric machine at a second engine will not necessarily have an increase in extracted torque or power. Furthermore, embodiments provided herein allow for operation and control of the load device without direct communicative coupling between the electric machine and the load device. Additionally, embodiments provided herein allow for operating limit protection, such as electric propulsion engine overspeed protection, without requiring direct communicative coupling between the load device and the computing system.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures, <FIG> provides a top view of an exemplary vehicle <NUM> as may incorporate various embodiments of the present disclosure. <FIG> provides a port side view of the vehicle <NUM> as illustrated in <FIG>. As shown in <FIG> collectively, the vehicle <NUM> defines a longitudinal centerline <NUM> that extends therethrough, a vertical direction V, a lateral direction L, a forward end <NUM>, and an aft end <NUM>. Moreover, the vehicle <NUM> defines a mean line <NUM> extending between the forward end <NUM> and aft end <NUM> of the vehicle <NUM>. As used herein, the "mean line" refers to a midpoint line extending along a length of the vehicle <NUM>, not taking into account the appendages of the vehicle <NUM> (such as the wings <NUM> and stabilizers discussed below).

Moreover, the vehicle <NUM> includes a fuselage <NUM>, extending longitudinally from the forward end <NUM> of the vehicle <NUM> towards the aft end <NUM> of the vehicle <NUM>, and a pair of wings <NUM>. As used herein, the term "fuselage" generally includes all of the body of the vehicle <NUM>, such as an empennage of the vehicle <NUM>. The first of such wings <NUM> extends laterally outwardly with respect to the longitudinal centerline <NUM> from a port side <NUM> of the fuselage <NUM> and the second of such wings <NUM> extends laterally outwardly with respect to the longitudinal centerline <NUM> from a starboard side <NUM> of the fuselage <NUM>. Each of the wings <NUM> for the exemplary embodiment depicted includes one or more leading edge flaps <NUM> and one or more trailing edge flaps <NUM>. The vehicle <NUM> further includes a vertical stabilizer <NUM> having a rudder flap <NUM> for yaw control, and a pair of horizontal stabilizers <NUM>, each having an elevator flap <NUM> for pitch control. The fuselage <NUM> additionally includes an outer surface or skin <NUM>. It should be appreciated however, that in other exemplary embodiments of the present disclosure, the vehicle <NUM> may additionally or alternatively include any other suitable configuration of stabilizer that may or may not extend directly along the vertical direction V or horizontal/ lateral direction L.

The exemplary vehicle <NUM> of <FIG> includes a propulsion system <NUM>, herein referred to as "system <NUM>". The exemplary system <NUM> includes one or more aircraft engines and one or more electric propulsion engines. For example, the embodiment depicted includes a plurality of aircraft engines, each configured to be mounted to the vehicle <NUM>, such as to one of the pair of wings <NUM>, and an electric propulsion engine <NUM>. More specifically, for the embodiment depicted, the aircraft engines are configured as gas turbine engines, or rather as turbofan engines <NUM>, <NUM> attached to the wings <NUM>. In a particular configuration, the engines <NUM>, <NUM> are suspended beneath the wings <NUM> in an under-wing configuration. However, the vehicle <NUM> may attach the engines <NUM>, <NUM> in any appropriate configuration (e.g., over-wing, within or through the wing, fuselage-mounted, etc.) In certain embodiments, the electric propulsion engine <NUM> is configured to be mounted at the aft end of the vehicle <NUM>. Further, the electric propulsion engine depicted may be configured to ingest and consume air forming a boundary layer over the fuselage <NUM> of the vehicle <NUM>. Accordingly, the exemplary electric propulsion engine <NUM> depicted may be referred to as a boundary layer ingestion (BLI) fan. In the embodiment depicted, the electric propulsion engine <NUM> is mounted to the vehicle <NUM> at a location aft of the wings <NUM> and/or the engines <NUM>, <NUM>. For a BLI fan embodiment of the electric propulsion engine <NUM>, the electric propulsion engine <NUM> is fixedly connected to the fuselage <NUM> at the aft end <NUM>, such that the electric propulsion engine <NUM> is incorporated into or blended with a tail section at the aft end <NUM>, and such that the mean line <NUM> extends therethrough. It should be appreciated, however, that in other embodiments the electric propulsion engine <NUM> may be configured in any other suitable manner, such as at the fuselage <NUM> or the wings <NUM>. In still various embodiments, the electric propulsion engine <NUM> may not necessarily be configured as an aft fan or as a BLI fan.

Referring still to the embodiment of <FIG>, in certain embodiments the propulsion system further includes one or more electric generators <NUM> operable with the engines <NUM>, <NUM>. For example, one or both of the engines <NUM>, <NUM> may be configured to provide mechanical power from a rotating shaft (such as an LP shaft or HP shaft) to the electric generators <NUM>. Although depicted schematically outside the respective engines <NUM>, <NUM>, in certain embodiments, the electric generators <NUM> may be positioned within a respective engine <NUM>, <NUM> (e.g., such as depicted and described herein with regard to <FIG>). Additionally, the electric generators <NUM> may be configured to convert the mechanical power to electrical power. For the embodiment depicted, the propulsion system <NUM> includes an electric generator <NUM> for each engine <NUM>, <NUM>, and also includes a power conditioner <NUM> and an energy storage device <NUM>. The electric generators <NUM> may send electrical power to the power conditioner <NUM>, which may transform the electrical energy to a proper form and either store the energy in the energy storage device <NUM> or send the electrical energy to the electric propulsion engine <NUM>. For the embodiment depicted, the electric generators <NUM>, power conditioner <NUM>, energy storage device <NUM>, and electric propulsion engine <NUM> are all are connected to an electric communication bus <NUM>, such that the electric generator <NUM> may be in electrical communication with the electric propulsion engine <NUM> and/or the energy storage device <NUM>, and such that the electric generator <NUM> may provide electrical power to one or both of the energy storage device <NUM> or the electric propulsion engine <NUM>. Accordingly, in such an embodiment, the propulsion system <NUM> may be referred to as a gas-electric or hybrid-electric propulsion system.

It should be appreciated, however, that the vehicle <NUM> and propulsion system <NUM> depicted in <FIG> is provided by way of example only and that in other exemplary embodiments of the present disclosure, any other suitable vehicle <NUM> may be provided having a propulsion system <NUM> configured in any other suitable manner. For example, it should be appreciated that in various other embodiments, the electric propulsion engine <NUM> may alternatively be positioned at any suitable location proximate the aft end <NUM> of the vehicle <NUM>. Further, in still other embodiments the electric propulsion engine may not be positioned at the aft end of the vehicle <NUM>, and thus may not be configured as an "aft engine. " For example, in other embodiments, the electric propulsion engine may be incorporated into the fuselage of the vehicle <NUM>, and thus configured as a "podded engine," or pod-installation engine. Further, in still other embodiments, the electric propulsion engine may be incorporated into a wing of the vehicle <NUM>, and thus may be configured as a "blended wing engine. " Moreover, in other embodiments, the electric propulsion engine may not be a boundary layer ingestion fan, and instead may be mounted at any suitable location on the vehicle <NUM> as a freestream injection fan. Furthermore, in still other embodiments, the propulsion system <NUM> may not include, e.g., the power conditioner <NUM> and/or the energy storage device <NUM>, and instead the generator(s) <NUM> may be directly connected to the electric propulsion engine <NUM>.

Referring now to <FIG>, a schematic cross-sectional view of a propulsion engine in accordance with an exemplary embodiment of the present disclosure is provided. In certain exemplary embodiments, the propulsion engine may be configured a high-bypass turbofan engine <NUM>, herein referred to as "engine <NUM>. " Notably, in at least certain embodiments, the engines <NUM>, <NUM> may be also configured as high-bypass turbofan engines. In various embodiments, the gas turbine engine <NUM> may be representative of engines <NUM>, <NUM>. Alternatively, however, in other embodiments, the gas turbine engine <NUM> may be incorporated into any other suitable vehicle <NUM> or propulsion system <NUM>.

As shown in <FIG>, the gas turbine engine <NUM> defines an axial direction A1 (extending parallel to a longitudinal centerline <NUM> provided for reference) and a radial direction R1. In general, the gas turbine engine <NUM> includes a fan section <NUM> and a core turbine engine <NUM> disposed downstream from the fan section <NUM>.

The exemplary core turbine engine <NUM> depicted generally includes a substantially tubular outer casing <NUM> that defines an annular inlet <NUM>. The outer casing <NUM> encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor <NUM> and a high pressure (HP) compressor <NUM>; a combustion section <NUM>; a turbine section including a high pressure (HP) turbine <NUM> and a low pressure (LP) turbine <NUM>; and a jet exhaust nozzle section <NUM>. A high pressure (HP) shaft or spool <NUM> drivingly connects the HP turbine <NUM> to the HP compressor <NUM>. A low pressure (LP) shaft or spool <NUM> drivingly connects the LP turbine <NUM> to the LP compressor <NUM>.

For the embodiment depicted, the fan section <NUM> includes a variable pitch fan <NUM> having a plurality of fan blades <NUM> coupled to a disk <NUM> in a spaced apart manner. As depicted, the fan blades <NUM> extend outwardly from disk <NUM> generally along the radial direction R1. Each fan blade <NUM> is rotatable relative to the disk <NUM> about a pitch axis P by virtue of the fan blades <NUM> being operatively coupled to a suitable actuation member <NUM> configured to collectively vary the pitch of the fan blades <NUM> in unison. The fan blades <NUM>, disk <NUM>, and actuation member <NUM> are together rotatable about the longitudinal axis <NUM> by LP shaft <NUM> across a power gear box <NUM>. The power gear box <NUM> includes a plurality of gears for stepping down the rotational speed of the LP shaft <NUM> to a more efficient rotational fan speed.

Referring still to the exemplary embodiment of <FIG>, the disk <NUM> is covered by rotatable front hub <NUM> aerodynamically contoured to promote an airflow through the plurality of fan blades <NUM>. Additionally, the exemplary fan section <NUM> includes an annular fan casing or outer nacelle <NUM> that circumferentially surrounds the fan <NUM> and/or at least a portion of the core turbine engine <NUM>. It should be appreciated that the nacelle <NUM> may be configured to be supported relative to the core turbine engine <NUM> by a plurality of circumferentially-spaced outlet guide vanes <NUM>. Moreover, a downstream section <NUM> of the nacelle <NUM> may extend over an outer portion of the core turbine engine <NUM> so as to define a bypass airflow passage <NUM> therebetween.

Additionally, the exemplary gas turbine engine <NUM> depicted includes an electric machine <NUM> rotatable with the LP shaft <NUM>. Specifically, for the embodiment depicted, the electric machine <NUM> is configured as an electric generator co-axially mounted to and rotatable by the LP shaft <NUM>. For the embodiment depicted, the LP shaft <NUM> also rotates the fan <NUM> through the power gearbox <NUM>. The electric machine <NUM> includes a rotor <NUM> and a stator <NUM>. In certain exemplary embodiments, the rotor <NUM> and stator <NUM> of the electric machine <NUM> are configured in substantially the same manner as the exemplary rotor and stator of the electric motor <NUM> described below with reference to <FIG>. The electric machine <NUM> depicted and described with regard to <FIG> may further form the electric machine <NUM> described below with reference to <FIG>. Additionally, as will be appreciated, the rotor <NUM> may be attached to the LP shaft <NUM> and the stator <NUM> may remain static within the core turbine engine <NUM>. During operation, the electric machine may define an electric machine tip speed (i.e., a linear speed of the rotor <NUM> at an airgap radius of electric machine <NUM>, as described below). Notably, when the engine <NUM> is integrated into the propulsion system <NUM> described above with reference to <FIG>, the electric generators <NUM> may be configured in substantially the same manner as the electric machine <NUM> of <FIG>. In particular embodiments, the electric generators <NUM> in <FIG> may form the electric machine <NUM> of <FIG>, and/or form the electric machine <NUM> of <FIG>.

It should also be appreciated, however, that the exemplary engine <NUM> depicted in <FIG> is by way of example only, and that in other exemplary embodiments, the turbofan engine <NUM> may have any other suitable configuration. For example, although rotor <NUM> is illustrated as being attached to the LP shaft <NUM>, it should be appreciated that rotor <NUM> could alternatively be attached to the HP shaft <NUM> or any other suitable shaft. Additionally, or alternatively, although the electric machine <NUM> is depicted at an aft end of the engine <NUM> in <FIG>, the electric machine <NUM> may be positioned at a forward or mid-portion of the engine <NUM>, or any other appropriate part of the engine <NUM> or vehicle <NUM> provided herein. Further, it should be appreciated, that in other exemplary embodiments, the engines <NUM>, <NUM> may instead be configured as any other suitable aeronautical engine, such as a turboprop engine, turbojet engine, internal combustion engine, reciprocating engine, combined-cycle engine, etc..

Referring now to <FIG>, a schematic, cross-sectional side view of an electric propulsion engine in accordance with various embodiments of the present disclosure is provided. The electric propulsion engine depicted may be mounted to a vehicle <NUM> at an aft end <NUM> of the vehicle <NUM> and is configured to ingest a boundary layer air. Accordingly, for the embodiment depicted, the electric propulsion engine may be configured as a boundary layer ingestion (BLI) fan. The electric propulsion engine <NUM> may be configured in substantially the same manner as the electric propulsion engine <NUM> described above with reference to <FIG> and the vehicle <NUM> may be configured in substantially the same manner as the exemplary vehicle <NUM> described above with reference to <FIG>.

As shown in <FIG>, the electric propulsion engine <NUM> defines an axial direction A2 extending along a longitudinal centerline axis <NUM> (or center axis) that extends therethrough for reference, as well as a radial direction R2 and a circumferential direction C2 (a direction extending about the axial direction A2, not shown). Additionally, the vehicle <NUM> defines a mean line <NUM> extending therethrough.

In general, the electric propulsion engine <NUM> includes a fan <NUM> rotatable about the centerline axis <NUM> and a structural support system <NUM>. The structural support system <NUM> is configured for mounting the electric propulsion engine <NUM> to the vehicle <NUM>, and for the embodiment depicted generally includes an inner frame support <NUM>, a plurality of forward support members <NUM>, an outer nacelle <NUM>, a plurality of aft support members <NUM>, and a tail cone <NUM>. As is depicted, the inner frame support <NUM> is attached to a bulkhead <NUM> of the fuselage <NUM>. The plurality of forward support members <NUM> are attached to the inner frame support <NUM> and extend outward generally along the radial direction R2 to the nacelle <NUM>. The nacelle <NUM> defines an airflow passage <NUM> with an inner casing <NUM> of the electric propulsion engine <NUM>, and at least partially surrounds the fan <NUM>. Further, for the embodiment depicted, the nacelle <NUM> extends substantially three hundred and sixty degrees (<NUM>°) around the mean line <NUM> of the vehicle <NUM>. The plurality of aft support members <NUM> also extend generally along the radial direction R2 from, and structurally connect, the nacelle <NUM> to the tail cone <NUM>.

In certain embodiments, the forward support members <NUM> and the aft support members <NUM> may each be generally spaced along the circumferential direction C2 of the electric propulsion engine <NUM>. Additionally, in certain embodiments the forward support members <NUM> may be generally configured as inlet guide vanes and the aft support members <NUM> may generally be configured as outlet guide vanes. If configured in such a manner, the forward and aft support members <NUM>, <NUM> may direct and/or condition an airflow through the airflow passage <NUM> of the electric propulsion engine <NUM>. Notably, one or both of the forward support members <NUM> or aft support members <NUM> may additionally be configured as variable guide vanes. For example, the support member may include a flap (not shown) positioned at an aft end of the support member for directing a flow of air across the support member.

It should be appreciated, however, that in other exemplary embodiments, the structural support system <NUM> may instead include any other suitable configuration and, e.g., may not include each of the components depicted and described above. Alternatively, the structural support system <NUM> may include any other suitable components not depicted or described above.

The electric propulsion engine <NUM> additionally defines a nozzle <NUM> between the nacelle <NUM> and the tail cone <NUM>. The nozzle <NUM> may be configured to generate an amount of thrust from the air flowing therethrough, and the tail cone <NUM> may be shaped to minimize an amount of drag on the electric propulsion engine <NUM>. However, in other embodiments, the tail cone <NUM> may have any other shape and may, e.g., end forward of an aft end of the nacelle <NUM> such that the tail cone <NUM> is enclosed by the nacelle <NUM> at an aft end. Additionally, in other embodiments, the electric propulsion engine <NUM> may not be configured to generate any measurable amount of thrust, and instead may be configured to ingest air from a boundary layer of air of the fuselage <NUM> of the vehicle <NUM> and add energy/ speed up such air to reduce an overall drag on the vehicle <NUM> (and thus increase a net thrust of the vehicle <NUM>).

Referring still to <FIG>, the fan <NUM> includes a plurality of fan blades <NUM> and a fan shaft <NUM>. The plurality of fan blades <NUM> are attached to the fan shaft <NUM> and spaced generally along the circumferential direction C2 of the electric propulsion engine <NUM>. As depicted, the plurality fan blades <NUM> are, for the embodiment depicted, at least partially enclosed by the nacelle <NUM>.

Moreover, for the embodiment depicted, the fan <NUM> is rotatable about the centerline axis <NUM> of the electric propulsion engine <NUM> by an electric machine. More particularly, for the embodiment depicted, the electric machine is configured as an electric motor <NUM> and the electric propulsion engine <NUM> additionally includes a power gearbox <NUM> mechanically coupled to the electric motor <NUM>. Additionally, the fan <NUM> is mechanically coupled to the power gearbox <NUM>. For example, for the embodiment depicted, the fan shaft <NUM> extends to and is coupled to the power gearbox <NUM>, and a driveshaft <NUM> of the electric motor <NUM> extends to and is also coupled to the power gearbox <NUM>. Accordingly, for the embodiment depicted, the fan <NUM> is rotatable about the central axis <NUM> of the electric propulsion engine <NUM> by the electric motor <NUM> through the power gearbox <NUM>.

The power gearbox <NUM> may include any type of gearing system for altering a rotational speed between the driveshaft <NUM> and the fan shaft <NUM>. For example, the power gearbox <NUM> may be configured as a star gear train, a planetary gear train, or any other suitable gear train configuration. Additionally, the power gearbox <NUM> may define a gear ratio, which as used herein, refers to a ratio of a rotational speed of the driveshaft <NUM> to a rotational speed of the fan shaft <NUM>. In certain exemplary embodiments, the gear ratio of the power gearbox <NUM> may be greater than about <NUM>:<NUM> and less than about <NUM>:<NUM>. For example, in certain embodiments, the gear ratio of the power gearbox <NUM> may be between about <NUM>:<NUM> and about <NUM>:<NUM>, such as between about <NUM>:<NUM> and about <NUM>:<NUM>. It should be appreciated, that as used herein, terms of approximation, such as "about" or "approximately," refer to being within a <NUM>% margin of error.

Referring still to the exemplary embodiment of <FIG>, the electric motor <NUM> is located at least partially within the fuselage <NUM> of the vehicle <NUM>. More specifically, the fan <NUM> is positioned forward of the power gearbox <NUM> along the central axis <NUM> of the electric propulsion engine <NUM>, and the electric motor <NUM> is positioned forward of the fan <NUM> along the central axis <NUM> of the electric propulsion engine <NUM>. However, according to alternative embodiments, power gearbox <NUM> could be positioned at a forward location or at any other suitable location within vehicle <NUM>.

Further, in certain exemplary embodiments, the electric propulsion engine <NUM> may be configured with a gas-electric propulsion system, such as the gas-electric propulsion system <NUM> described above with reference to <FIG>. In such an embodiment, the electric motor <NUM> may receive power from one or both of an energy storage device or an electric generator, such as the energy storage device <NUM> or electric generator <NUM> of <FIG>.

Referring now to <FIG>, a schematic diagram of a system for controlling power distribution at a hybrid-electric system is provided (hereinafter, "system <NUM>"). Embodiments of the system <NUM> include an engine <NUM> operably coupled to an electric machine <NUM>. Various embodiments of the system <NUM> depicted in <FIG> may be configured in accordance with the vehicle <NUM> depicted and described with regard to <FIG>; the engine <NUM> depicted and described with regard to <FIG>; and/or the electric propulsion engine <NUM> depicted and described with regard to <FIG>, such as further described below.

In various embodiments, the system <NUM> includes a computing system <NUM> configured to output command controls, perform operations, and/or store one or more charts, graphs, tables, curves, limits, or schedules in accordance with operations, instructions, steps, or methods described herein. The computing system <NUM> is communicatively coupled to the engine <NUM> to generate power or torque to be extracted by the electric machine <NUM> to generate electric power to the load device <NUM>. The computing system <NUM> is communicatively coupled a first power electronics device <NUM>. The first power electronics device <NUM> is any appropriate power conditioning device for converting a current to or from DC to AC, or DC to DC, in accordance with aspects of this disclosure. In a particular embodiment, the first power electronics device <NUM> is a first inverter. The first power electronics device <NUM> is configured in a power or torque control mode. As such, the first power electronics device <NUM> regulates or otherwise controls an amount of power extracted by the electric machine <NUM> from the engine <NUM> within a torque limit associated with the engine <NUM>. In particular embodiments, the first power electronics device <NUM> commands the electric machine <NUM> to extract power from the engine <NUM>. Power extraction by the electric machine <NUM> from the engine <NUM> is correspondingly within a voltage limit at the electric bus <NUM>.

The computing system <NUM> is in operable communication with the first power electronics device <NUM> and the engine <NUM>. As such, the computing system <NUM> provides and outputs control commands to the engine <NUM> to generate power or torque in accordance with one or more engine operating limits. The engine operating limits include, but are not limited to, surge margin or stall margin at one or more compressors (e.g., LP compressor <NUM>, HP compressor <NUM>), an exhaust gas temperature (e.g., combustion gases generated by the combustion section <NUM> and expanded through the turbines <NUM>, <NUM>), one or more pressure ratios (e.g., compressor pressure ratio at one or both compressors <NUM>, <NUM>, fan pressure ratio at <NUM>), rotational speed (e.g., at one or more spools <NUM>, <NUM>), or combinations thereof, or minimum and/or maximum limits associated therewith, or changes therein, or rates of change therein. The engine operating limits may generally include any appropriate limit, margin, range, or ratio associated with operability, performance, health, safety, or desired durability of a gas turbine engine. Furthermore, the computing system <NUM> provides and outputs control commands associate with desired power outputs from the electric machine <NUM> to the load device <NUM>. The first power electronics device <NUM>, in a power or torque control configuration, alters or modulates torque extracted by the electric machine <NUM> from the engine <NUM>. The amount of torque extracted accordingly controls or modulates an amount of power output through an electric bus <NUM> operably connecting the first power electronics device <NUM> to a second power electronics device <NUM> and load device <NUM>.

The second power electronics device <NUM> is any appropriate power conditioning device for converting a current to or from DC to AC, or DC to DC, in accordance with aspects of this disclosure. In a particular embodiment, the second power electronics device <NUM> is a second inverter. The second power electronics device <NUM> is configured in a voltage control mode. As such, the second power electronics device <NUM> regulates or otherwise controls an amount of power, or current, provided from the first power electronics device <NUM> to the load device <NUM>. In particular embodiments, the second power electronics device <NUM> regulates the amount of power provided to the load device <NUM> based on a voltage at the electric bus <NUM>, such as a voltage limit.

Referring now to <FIG>, graphs depicting exemplary control curves of the system <NUM> are provided. <FIG> depicts a torque control graph <NUM> associated with the first power electronics device <NUM>. <FIG> depicts a voltage control graph <NUM> associated with the second power electronics device <NUM>. Referring to <FIG>, <FIG>, during an exemplary embodiment of operation of the system <NUM>, the computing system <NUM> commands the engine <NUM> to operate, such as to generate torque to be extracted by the electric machine <NUM> to generate power to the load device <NUM>. The graph <NUM> at <FIG> depicts torque extraction <NUM> from the engine <NUM>. The first power electronics device <NUM> controls or regulates the electric machine <NUM> to extract torque from the engine <NUM> within a nominal voltage zone <NUM>, such as depicted to the left of a voltage limit <NUM> depicted in <FIG>. The voltage limit <NUM> may particularly correspond to a voltage limit at the bus <NUM>. The first power electronics device <NUM> outputs power to the second power electronics device <NUM> through the electric bus <NUM>.

The second power electronics device <NUM> allows the load device(s) <NUM> to receive power through the bus <NUM> until the load device(s) <NUM> are operating within a nominal load device operation zone <NUM>, such as depicted to the left of an operating limit <NUM> depicted in <FIG>. The operating limit <NUM> corresponds to any appropriate operability, performance, health, safety, or other limit associated with operation of the load device <NUM>, such as described herein. The operating limit <NUM> may correspond to one or more predetermined operating parameters or limits for the load device <NUM> to operate at or within the operating limit <NUM> (i.e., within the nominal load device operation zone <NUM>). The second power electronics device <NUM> outputs power from the second power electronics device <NUM> to the load device <NUM> to maintain operation of the load device(s) <NUM> within the nominal load device operation zone <NUM>.

Various conditions may cause the load device(s) <NUM> to approach or exceed operating limit <NUM>, at which case the load device(s) is operating within an overlimit zone <NUM> (<FIG>). When the load device <NUM> is operating above the load device operating limit <NUM>, and accordingly within the overlimit zone <NUM> of the load device <NUM>, the second power electronics device <NUM> limits current to the load device <NUM> to return the load device <NUM> to within the nominal load device operating zone <NUM> (<FIG>). As current, and subsequently, power, received by the load device <NUM> is accordingly limited by the second power electronics device <NUM> to return the load device <NUM> to the nominal load device operating zone <NUM>, the first electronics device <NUM> senses, measures, or otherwise detects an increase in voltage at the bus <NUM>. Referring to <FIG>, when the first power electronics device <NUM> approaches or exceeds the voltage limit <NUM>, the measured voltage is within an overvoltage zone <NUM>. The first power electronics device <NUM> commands, controls, or otherwise modulates the electric machine <NUM> to adjust the amount of torque extracted from the engine <NUM>. Accordingly, the adjusted torque extraction decreases the power output from the electric machine <NUM>, and accordingly the voltage at the bus <NUM> is reduced to return to the nominal voltage zone <NUM>.

Briefly, it will be appreciated that in other exemplary aspects, the second power electronics device <NUM> may additionally or alternatively be configured to modulate power received by the load device <NUM> from the first power electronics device <NUM> based on a voltage of the electric bus <NUM>. The voltage may be the voltage limit <NUM> of the electric bus <NUM>, or may be a desired operating voltage for the electric bus <NUM> (e.g., based on an operating parameter of the engine, an operating schedule, etc.). For example, when the load device is operating below the overlimit zone <NUM>, but the electric bus <NUM> is at or exceeding the voltage limit <NUM>, the second power electronics device <NUM> may be operated to reduce the voltage of the electric bus <NUM> (e.g., by increasing power, or rather current, provided to the load device <NUM>).

Accordingly, the system <NUM> allows for the computing system <NUM> to control and command torque extraction from the engine <NUM> within the operability, performance, health, and safety limits of the engine <NUM> via regulating bus voltage (e.g., at bus <NUM>). The system <NUM> may particularly designate the engine <NUM> as a priority load at which the operating limits associated with the engine <NUM> are more carefully managed, regulated, or controlled relative to a secondary load at the load device(s) <NUM>. In particular, the system <NUM> allows for torque extraction to be a function of all operability, performance, health, or safety limits, ranges, etc. at the engine <NUM>. Stated differently, the system <NUM> allows for changes in torque extraction (i.e., magnitudes of change and/or rates of change) from the engine <NUM> for power provided to the load device(s) <NUM> occurs within all limits associated with the engine <NUM>. As such, the system <NUM> may obviate or remove a need for control commands or communication between the computing system <NUM> and the load device(s) <NUM>, which may simplify control systems, reduce weight, reduce failure modes, and improve overall performance. Additionally, or alternatively, the load device <NUM> may be any electrically-driven device that allows for fluctuations in operating state relative to a nominal operating state. For instance, the load device configured as an electric propulsion engine may allow for changes in operating state (e.g., rotational speed, power or thrust output, pressure ratio, or temperature, etc.) of up to <NUM>% from a nominal load device operating zone of the load device.

Referring now to <FIG>, a schematic diagram is provided of an embodiment of the vehicle <NUM> such as described with regard to <FIG> including an embodiment of the system <NUM> such as described with regard to <FIG>. The embodiment provided in <FIG> includes the power conditioner <NUM> including one or both of the first power electronics device <NUM> and the second power electronics device <NUM> such as described in regard to <FIG>. It should be appreciated that although the power conditioner <NUM> is depicted as including the first power electronics device <NUM> and the second power electronics device <NUM>, other embodiments of the vehicle <NUM> and system <NUM> may separate the first power electronics device <NUM> and the second power electronics device <NUM> from the power conditioner <NUM>.

The embodiment provided in <FIG> includes one or both engines <NUM>, <NUM> generating power via torque extracted by the electric generator(s) <NUM>. The engine <NUM>, <NUM> corresponds to the engine <NUM> depicted and described with regard to <FIG>. The electric generator <NUM> corresponds to the electric machine <NUM> depicted and described with regard to <FIG>. The electric propulsion engine <NUM> corresponds to the load device(s) <NUM> depicted and described with regard to <FIG>. The engine <NUM>, <NUM>, the electric generator <NUM>, the power conditioner <NUM>, and the electric propulsion engine <NUM> are in operable communication via the electric communication bus <NUM>, corresponding at least in part to the bus <NUM> depicted and described with regard to <FIG>. In particular, the electric communication bus <NUM> may include a first portion 111a operably connecting the electric generator <NUM> to the first power electronics device; a second portion 111b operability connecting the second power electronics device <NUM> to the electric propulsion engine <NUM>, and the voltage bus <NUM> operably connecting the first power electronics device <NUM> and the second power electronics device <NUM>, such as described with regard to <FIG>.

Although not further depicted herein, the schematic diagram of the vehicle <NUM> depicted in <FIG> may further include one or more of the energy storage device <NUM> in operable arrangement with the electric generator <NUM>, the power conditioner <NUM>, and/or via the electric communication bus <NUM>.

During operation of the vehicle <NUM>, various factors may cause the electric propulsion engine <NUM> to require varying amounts of power for operation within the nominal load device operation zone <NUM>, or at the limit <NUM>, or generally outside of the overlimit zone <NUM>, such as depicted and described with regard to <FIG>. For instance, changes in density, speed, temperature, pressure, or boundary layer conditions of air at the electric propulsion engine <NUM> may cause the electric propulsion engine <NUM> to require changes in power received at the electric propulsion engine <NUM> for desired operation. Such changes may be based on changes in altitude, attitude, ambient condition, vehicle speed, Mach number, or other operating conditions of the vehicle <NUM>. When the electric propulsion engine <NUM> is at or approaching the overlimit zone <NUM>, such as a temperature limit, a flow rate limit, a rotational speed limit (e.g., rotor speed, blade tip speed, etc.), pressure ratio, or other appropriate limit associated with operability, performance, health, or safety of the electric propulsion engine <NUM>, the second power electronics device <NUM> accordingly reduces the power or current received at the electric propulsion engine <NUM>, such as to maintain or return the electric propulsion engine <NUM> to the nominal load device operating zone <NUM> depicted in <FIG>.

As the power or current decreases, the first power electronics device <NUM> senses an increase in voltage at the bus <NUM> and controls the electric generator <NUM> to reduce torque extraction from one or more engines <NUM>, <NUM>. Particularly, the command or control to reduce torque extraction is based at least on the operating parameters for the engine <NUM>, <NUM> stored at the computing system <NUM>. Accordingly, power generated by the electric generator <NUM> is reduced and the voltage is maintained within the nominal voltage zone <NUM>, or reduced from the overvoltage zone <NUM>. Furthermore, the magnitude and/or rate of change of torque extraction from the engine <NUM>, <NUM> is based on operability, performance, health, and/or safety limits of the engine <NUM>, <NUM> stored at the computing system <NUM>.

As such, the vehicle <NUM> allows for overlimit protection (e.g., overspeed protection, over-temperature protection, etc.) of the electric propulsion engine <NUM> without requiring command control communication between electric propulsion engine control (e.g., the second power electronics device <NUM>) and the computing system <NUM>. Additionally, or alternatively, the vehicle <NUM> allows for such protections without requiring command control communication between the electric generator <NUM> and the electric propulsion engine <NUM>.

Referring now to <FIG>, a schematic diagram is provided of an embodiment of the system <NUM> such as described with regard to <FIG>, including an embodiment of the engine <NUM> such as described with regard to <FIG>, and including an embodiment of the electric propulsion engine <NUM> described with regard to <FIG>. The embodiment provided in <FIG> may be configured substantially similarly as described with regard to any one or more embodiments described with regard to <FIG>. <FIG> may include components or elements depicted and described with regard to <FIG>, and such components may be removed for clarity.

The embodiment provided in <FIG> includes one or more engines <NUM> generating electric power via torque extracted by the electric machine <NUM> via a shaft <NUM> (e.g., HP shaft <NUM> or LP shaft <NUM> in <FIG>). The electric machine <NUM>, such as described with regard to <FIG>, may further include the electric machine <NUM> and the first power electronics device <NUM> such as described with regard to <FIG>. The engine <NUM> corresponds to the engine <NUM> depicted and described with regard to <FIG>. The electric propulsion engine <NUM>, such as described with regard to <FIG>, may further include the second power electronics device <NUM> such as described with regard to <FIG>. The electric motor <NUM>, such as described with regard to <FIG>, corresponds to the load device(s) <NUM> depicted and described with regard to <FIG>. The engine <NUM>, the electric machine <NUM>, and the electric propulsion engine <NUM> are in operable communication via the bus <NUM> (including the first and second portions 111a, 111b), <NUM>, such as described with regard to <FIG>.

Operation of the embodiment of the system <NUM> such as provided with regard to <FIG> is substantially similar as described with regard to any one or more embodiments of <FIG>. It should be appreciated that the operating limit <NUM>, the nominal load device operating zone <NUM>, and the overlimit zone <NUM> may correspond to any appropriate operability, performance, health, and/or safety limit of the electric motor <NUM>. Such parameters or limits may include, but are not limited to, temperature, power output, or speed of the electric motor <NUM>. Such limits may additionally, or alternatively, include one or more limits corresponding to the fan <NUM> (<FIG>) configured to receive power from the electric motor <NUM>.

The system <NUM> provided with regard to <FIG> allows for overlimit protection (e.g., overspeed protection, over-temperature protection, etc.) of the electric propulsion engine <NUM> without requiring command control communication between electric propulsion engine <NUM> and the computing system <NUM>. Additionally, or alternatively, the vehicle <NUM> allows for such protections to the electric propulsion engine <NUM> without requiring command control communication between the electric machine <NUM> and the electric motor <NUM> distributing power to the fan <NUM> (<FIG>).

In a particular embodiment, the vehicle <NUM> and system <NUM> may allow for the load device <NUM>, such as the electric propulsion engine <NUM>, <NUM> to automatically generate propulsive power in the event of a failure at the engine <NUM>, <NUM>, <NUM>, <NUM>, or computing system <NUM>. As the second power electronics device <NUM> is configured to control or maintain the load device <NUM> within the nominal load device operating zone <NUM>, the second power electronics device <NUM> may allow for increases in current or power through the bus <NUM> to the load device <NUM> when the operating parameter associated with the operating limit <NUM> decreases below a minimum or margin relative to the operating limit <NUM>. As the second power electronics device <NUM> would control for this increase without regard for functions, controls, or operating states at the computing system <NUM> or engine <NUM>, the system <NUM> may draw power from any one or more energy storage devices <NUM> operably coupled to the second power electronics device <NUM> via the electric communication bus <NUM>, such as depicted and described with regard to <FIG>.

Although <FIG> provide particular embodiments of the load device <NUM> as a boundary layer ingestion fan propulsion system, it should be appreciated that the load device <NUM> depicted and described herein may include any appropriate electrically-driven system. Various embodiments of the load device may be an electrically-driven device, such as a thrust-generating system (e.g., an electrically-driven propulsion system, a boundary layer ingestion (BLI) fan, a rotary wing device, a lift or tilt-rotor system, etc.), pumps, compressors, thermal systems (e.g., environmental control system (ECS), thermal management system (TMS), heating elements (e.g., anti-icing systems), radars, LIDARs, avionics, communications devices, directed-energy systems, electric motors, or other electrical systems at the vehicle.

The computing system <NUM> depicted and described herein can generally correspond to any suitable processor-based device, including one or more computing devices. Certain embodiments of the computing system <NUM> include a full authority digital engine controller (FADEC), a digital engine controller (DEC), a hybrid-electric engine controller, or other appropriate computing device configured to operate the engine <NUM>, electric machine <NUM>, and the first power electronics device <NUM>, or embodiments such as provided herein.

The computing system <NUM> may include one or more processors <NUM> and one or more associated memory devices <NUM> configured to perform a variety of computer-implemented functions, such as the methods described herein. As used herein, the term "processor" refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), a Field Programmable Gate Array (FPGA), and other programmable circuits. Additionally, the memory <NUM> can generally include memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., flash memory), a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD), non-transitory computer-readable media, and/or other suitable memory elements or combinations thereof.

The computing system <NUM> may include control logic <NUM> stored in the memory <NUM>. The control logic <NUM> may include computer-readable instructions that, when executed by the one or more processors <NUM>, cause the one or more processors <NUM> to perform operations. In various embodiments, the operations include one or more steps of a method for controlling or operating a hybrid-electric system (hereinafter, "method <NUM>"), such as outlined in the flowchart provided in <FIG>. The method <NUM> may be stored as computer-readable instructions and executed with any appropriate computing system, engine, load device, first power electronics device, and second power electronics device, such as depicted and described in various embodiments with regard to <FIG>.

The method <NUM> includes at <NUM> commanding the engine (e.g., engine <NUM>) to generate torque, such as via engine shaft <NUM> (e.g., shaft <NUM>, <NUM> in <FIG>) operably coupled to the electric machine <NUM> (<FIG>), to generate electric power. The method <NUM> at <NUM> may generally include operating the engine in accordance with operability, performance, health, and/or safety parameters associated with the engine.

The method <NUM> includes at <NUM> providing electric power to a load device (e.g., load device <NUM>) via a first power electronics device (e.g., first power electronics device <NUM>) in a power or torque control configuration and a second power electronics device (e.g., second power electronics device <NUM>) in a voltage control configuration, such as described with regard to <FIG> herein. In a particular embodiment, the method <NUM>, and the system <NUM> described herein, include the first power electronics device in serial connection via an electric bus (e.g., bus <NUM>) with the second power electronics device.

The method <NUM> includes at <NUM> controlling, via the second power electronics device, a load device operational parameter based on an operating limit at the load device (e.g., operating limit <NUM> in <FIG>). The operating limit may generally correspond to a minimum and/or maximum load device operating parameter, such as, but not limited to, one or more parameters associated with rotational speed, temperature, pressure, flow rate, power or thrust output, or other operating parameter at the load device. The second power electronics device operates in a voltage control mode to regulate the load device voltage within predetermined limits. Accordingly, the second power electronics device operates in voltage control mode by controlling the load device to operate within the predetermined operating limits for the load device.

The method <NUM> further includes at <NUM> controlling, via the first power electronics device, the voltage at an electric bus. In various embodiments, such as described with regard to <FIG> herein, the method <NUM> at <NUM> includes controlling, via the second power electronics device, controlling the load device operational parameter via controlling power output or current to the load device in correspondence with maintaining or operating within the voltage requirement associated with the operating limit. With regard to <FIG> herein, the method <NUM> at <NUM> includes controlling, via the first power electronics device, the voltage at the electric bus via controlling power or torque extraction from the electric machine. In a particular embodiment, the method <NUM> at <NUM> includes controlling power or torque extraction by the electric machine while maintaining the engine within operability, performance, health, and/or safety limits of the engine.

The instructions included at the control logic <NUM> and stored in the memory <NUM> can include one or more steps of the method <NUM> stored, converted, or written as software in any suitable programming language or code that can be implemented in hardware. Additionally, and/or alternatively, the instructions can be executed in logically and/or virtually separate threads on processor(s) <NUM>. The memory device(s) <NUM> can further store data that can be accessed by the processor(s), such as limits, charts, lookup tables, schedules, curves, or graphs associated with maintaining the engine within operability, performance, health, and/or safety limits of the engine (e.g., such as described with regard to step <NUM>), or graph <NUM> (<FIG>). The second power electronics device <NUM> may further include any appropriate hardware and/or software to store or otherwise control the load device <NUM> such as provided with regard to graph <NUM> and/or the method <NUM> at step <NUM>, or such as otherwise described herein.

The computing system <NUM> may also include a communications interface module <NUM>. In various embodiments, the communications interface module <NUM> can include associated electronic circuitry that is used to send and receive data or control commands such as described herein. As such, the communications interface module <NUM> of the computing system <NUM> can be used to receive data from one or more sensors, measurement devices, or calculations with regard to the engine <NUM>, the first power electronics device <NUM>, and the bus <NUM>. As described above, the communications interface module may communicate commands, modulations, adjustments, or other functions, or receive an operating parameter, a voltage state, and operating state, or other value indicative of a present or desired operating mode of the engine <NUM>, the electric machine <NUM>, and the first electronics device <NUM>. It should be appreciated that calculations or measurements corresponding thereto may include, but are not limited to, temperatures, pressures, voltages, currents, frequencies, wavelengths, flow rates, gradients, differences, or changes therein, or rates of change, other appropriate calculations or measurements such as described herein. In a particular embodiment, the system <NUM> is advantageously configured without communication between the computing system <NUM> and the second power electronics device <NUM> and the load device <NUM>, or particularly the load device configured as the electric propulsion engine <NUM>, <NUM>.

The computing system(s) <NUM> can also include a network interface used to communicate, for example, with the other components of system or apparatus. The network interface can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, and/or other suitable components.

It should be appreciated that the communications interface module <NUM> can be any combination of suitable wired and/or wireless communications interfaces and, thus, can be communicatively coupled to one or more components of the apparatus via a wired and/or wireless connection. As such, the computing system <NUM> may obtain, determine, store, generate, transmit, or operate any one or more steps of the method described herein via a distributed network. For instance, the network can include a SATCOM network, ACARS network, ARINC network, SITA network, AVICOM network, a VHF network, a HF network, a Wi-Fi network, a WiMAX network, a gatelink network, etc..

Embodiments of the system may provide particular advantages and benefits relative to hybrid-electric propulsion systems, such as by maintaining engine operation within all operability, performance, health, and/or safety limits associated with the engine. Such limits may particularly include stall or surge limits at one or more compressors, exhaust gas temperatures at or downstream of a turbine section, thrust outputs, rotational speeds at one or more spools, pressure ratios across one or more of a compressor section, a fan section, or a core engine, or changes therein, or rates of change therein. A particular advantage may include maintaining the engine within one or more such limits, or all such limits, while allowing the load device, such as the electric propulsion engine, to operate or "float" within relatively larger tolerances or limits relative to nominal operation of the load device. As such, changes in power requirements at the load device may not substantially affect operation of the engine within operability, performance, health, and/or safety limits at the engine. Such benefits may further be provided without direct communication between the computing system and the second power electronics device. Accordingly, the system and vehicle may decrease weight, complexity, and failure modes, such as by decreased wiring and communications devices, fewer interferences or conflicts between power demands and system limits between the engine and the load device, and separating potential failures at one component (e.g., the engine) from operation or operability at another component (e.g., the load device).

Claim 1:
A system for controlling power distribution, the system comprising:
an engine operably coupled to an electric machine (<NUM>, <NUM>);
a first power electronics device (<NUM>) operably coupled to the electric machine (<NUM>, <NUM>), wherein the first power electronics device (<NUM>) is configured to modulate power extracted by the electric machine (<NUM>, <NUM>) from the engine;
a second power electronics device (<NUM>) operably coupled to a load device (<NUM>), wherein the second power electronics device (<NUM>) is operably coupled to receive power from the first power electronics device (<NUM>) via an electric bus (<NUM>), and wherein the second power electronics device (<NUM>) is configured to modulate power received by the load device (<NUM>) from the first power electronics device (<NUM>), and wherein modulating power received by the load device (<NUM>) is based at least on an operating limit (<NUM>) corresponding to the load device (<NUM>), a voltage of the electric bus (<NUM>), or both; and wherein
the first power electronics device (<NUM>) is configured to sense, measure, or otherwise detect an increase in voltage at the electric bus (<NUM>); and
the first power electronics device (<NUM>) is further configured to, based on the sensed, measured, or otherwise detected increase in voltage at the electric bus (<NUM>), command, control, or otherwise modulate the electric machine (<NUM>, <NUM>) to decrease the amount of power extracted from the engine, and
a computing system operably coupled to the engine and the first power electronics device (<NUM>), wherein the computing system is configured to send control commands to the engine and the first power electronics device.