Method and apparatus for using model predictive control for hybrid electric propulsion system

1 . A method for a hybrid electric propulsion (HEP) system, comprising:

determining a target fan speed for a HEP system, the HEP system including a gas turbine engine and at least one electric motor configured to rotate a respective shaft of the gas turbine engine, and the HEP system having a plurality of operating limits;

determining an amount of electrical power that is currently available to the HEP system from one or more batteries configured to power the at least one electric motor;

determining which one of the plurality of operating limits the HEP system is approaching most quickly;

utilizing a model predictive control (MPC) to determine, based on the amount of electrical power that is currently available to the HEP system from the one or more batteries, and based on the plurality of operating limits of the HEP system, an effector command set that includes a power splitting profile indicating a power split between the gas turbine engine and the at least one electric motor for achieving the target fan speed, wherein said utilizing comprises utilizing the MPC to determine the power splitting profile to slow a rate at which the HEP system is approaching said one of the plurality of operating limits the HEP system is approaching most quickly; and

implementing the effector command set.

2 . The method of claim 1 , wherein:

the at least one electric motor includes a first electric motor configured to rotate a first shaft of the gas turbine engine, and a second electric motor configured to rotate a second shaft of the gas turbine engine; and

the power splitting profile indicates a power split between the gas turbine engine, the first electric motor, and the second electric motor.

3 . The method of claim 2 , comprising:

obtaining weights for a plurality of goals of the HEP system, the plurality of goals including the target fan speed and at least one prioritization goal for using at least one of the first electric motor and the second electric motor during flight;

wherein the MPC utilizes the weights to determine the effector command set.

4 . The method of claim 3 , wherein the target fan speed has a highest weighting of the plurality of goals.

5 . The method of claim 1 , comprising:

iteratively repeating said determining steps, said utilizing the MPC, and said implementing the effector command set for a plurality of sequential time periods.

6 . The method of claim 1 , wherein the plurality of operating limits includes operating limits for one or more of:

torque of the at least one electric motor;

a pressure in the gas turbine engine; and

a temperature in the gas turbine engine.

7 . The method of claim 1 , wherein the plurality of operating limits includes operating limits for one or more of:

a combustor of the gas turbine engine;

a stator vane of the gas turbine engine; and

one or more bleed valves of the gas turbine engine.

8 . The method of claim 1 , wherein the effector command set also includes commands for at least one of:

stator vane positions; and

bleed valve positions.

9 . A controller for a hybrid electric propulsion (HEP) system, comprising:

processing circuitry operatively connected to memory, and configured to:

determine a target fan speed for a HEP system, the HEP system including a gas turbine engine and at least one electric motor configured to rotate a respective shaft of the gas turbine engine, and the HEP system having a plurality of operating limits;

determine an amount of electrical power that is currently available to the HEP system from one or more batteries configured to power the at least one electric motor;

determine which one of the plurality of operating limits the HEP system is approaching most quickly;

utilize a model predictive control (MPC) to determine, based on the amount of electrical power that is currently available to the HEP system from the one or more batteries, and based on the plurality of operating limits of the HEP system, an effector command set that includes a power splitting profile indicating a power split between the gas turbine engine and the at least one electric motor for achieving the target fan speed, wherein the MPC is utilized to determine the power splitting profile to slow a rate at which the HEP system is approaching said one of the plurality of operating limits the HEP system is approaching most quickly; and

implement the effector command set.

10 . The controller of claim 9 , wherein:

the at least one electric motor includes a first electric motor configured to rotate a first shaft of the gas turbine engine, and a second electric motor configured to rotate a second shaft of the gas turbine engine; and

the power splitting profile indicates a power split between the gas turbine engine, the first electric motor, and the second electric motor.

11 . The controller of claim 10 , wherein the processing circuitry is configured to:

obtain weights for a plurality of goals of the HEP system, the plurality of goals including the target fan speed and at least one prioritization goal for using at least one of the first electric motor and the second electric motor during flight;

wherein the MPC utilizes the weights to determine the effector command set.

12 . The controller of claim 11 , wherein the target fan speed has a highest weighting of the plurality of goals.

13 . The controller of claim 9 , wherein the processing circuitry is configured to:

iteratively repeat the determination of the target fan speed, the determination of the amount of electrical power that is currently available to the HEP, the utilization of the MPC, and the implementation of the effector command set for a plurality of sequential time periods.

14 . The controller of claim 9 , wherein the plurality of operating limits includes operating limits for one or more of:

torque of the at least one electric motor;

a pressure in the gas turbine engine; and

a temperature in the gas turbine engine.

15 . The controller of claim 9 , wherein the plurality of operating limits includes operating limits for one or more of:

a combustor of the gas turbine engine;

a stator vane of the gas turbine engine; and

one or more bleed valves of the gas turbine engine.

16 . The controller of claim 9 , wherein the effector command set also includes commands for at least one of:

stator vane positions; and

bleed valve positions.