FIELD

The present subject matter relates generally to hybrid electric propulsion systems for aerial vehicles and methods for operating the same. More particularly the present subject matter is directed to control systems for hybrid electric propulsion systems for aerial vehicles that are configured for detecting and taking action in response to rapid electrical load changes.

BACKGROUND

Parallel hybrid electric propulsion systems for aerial vehicles typically include a combustion engine or other mechanically-driven powerplant that drives a generator to produce electrical power. The combustion engine may also drive a source of thrust for the aerial vehicle, such as a propeller. The electrical power generated by the generator is utilized to drive an additional source of thrust. For instance, the electrical power may be provided to an electric motor that utilizes the electrical power to drive the additional thrust source, such as a propeller on the other side of the aerial vehicle.

Such systems inherently contain single failures that, due to electrical coupling, can produce changes in vehicle thrust and thrust asymmetry that are more severe than non-hybrid systems. Moreover, rapid electrical load changes may cause significant and unsafe aircraft handling issues. Additionally, rapid changes to engine torque can lead to overspeed issues, among others.

Accordingly, a control system for a hybrid electric propulsion system for an aerial vehicle and methods therefore that address one or more of the challenges noted above would be useful.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one aspect, the present disclosure is directed to a hybrid electric propulsion system for an aerial vehicle. The hybrid electric propulsion system includes an engine and a first electric machine mechanically coupled with the engine and configured to generate electrical power when driven by the engine. The hybrid electric propulsion system also includes one or more power consuming loads electrically coupled with the first electric machine and configured to receive electrical power from the first electric machine. The one or more power consuming loads include a second electric machine, among other potential power consuming loads. Further, the hybrid electric propulsion system includes a propulsion assembly mechanically coupled with the second electric machine and configured to produce thrust when driven by the second electric machine. Moreover, the hybrid electric propulsion system includes one or more sensing devices positioned onboard the aerial vehicle for detecting one or more performance indicators indicative of an electrical load on the engine. In addition, the hybrid electric propulsion system includes one or more controllers communicatively coupled with the one or more sensors. The one or more controllers are configured to receive, from the one or more sensing devices, the one or more performance indicators indicative of the electrical load on the engine; determine whether an electrical load change is present based at least in part on the one or more performance indicators; and generate, if the rapid electrical load change is present, a control action in response to the electrical load change.

In another aspect, the present disclosure is directed to a method for operating a hybrid electric propulsion system for an aerial vehicle. The method includes receiving, from one or more sensing devices positioned onboard the aerial vehicle, one or more performance indicators indicative of an electrical load on the engine, the engine mechanically coupled with an electric machine configured to generate electrical power when driven by the engine, the electric machine electrically coupled with one or more power consuming devices, wherein at least one of the one or more power consuming devices are mechanically coupled with a propulsion assembly. The method also includes determining whether an electrical load decrease on the engine is present based at least in part on the one or more performance indicators. The method further includes generating, if the electrical load decrease on the engine is present, a control action in response to the electrical load decrease, wherein generating the control action comprises reducing a fuel flow to the engine.

In a further aspect, the present disclosure is directed to a hybrid electric propulsion system for an aerial vehicle. The hybrid electric propulsion system includes an engine. The hybrid electric propulsion system also includes a first propulsion assembly mechanically coupled with the engine and configured to produce thrust when driven by the engine. Further, the hybrid electric propulsion system includes a first electric machine mechanically coupled with the engine and configured to generate electrical power when driven by the engine. Moreover, the hybrid electric propulsion system includes a second electric machine electrically coupled with the first electric machine and configured to receive electrical power from the first electric machine. In addition, the hybrid electric propulsion system includes a second propulsion assembly mechanically coupled with the second electric machine and configured to produce thrust when driven by the second electric machine. The hybrid electric propulsion system also includes one or more sensing devices positioned onboard the aerial vehicle for detecting one or more performance indicators indicative of an electrical load on the engine. Moreover, the hybrid electric propulsion system includes one or more controllers communicatively coupled with the one or more sensors, the one or more controllers configured to: receive, from the one or more sensing devices, the one or more performance indicators indicative of the electrical load on the engine; determine whether an electrical load change is present based at least in part on the one or more performance indicators; and generate, if the electrical load change is present, a control action in response to the electrical load change.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

