Aircraft propulsion system with voltage regulator

1. An aircraft propulsion system for an aircraft, comprising:

a propeller;

an electric machine configured to operably rotate the propeller;

an electrical power source having a power output and configured to provide electrical power to the electric machine; and

a voltage regulator configured to regulate the electrical power at the power output by controlling the voltage provided to the electric machine as a function of ambient air pressure in at least one portion of the aircraft.

2. The aircraft propulsion system of claim 1 further comprising an electrical conductor connecting the voltage regulator to the electric machine and the at least one portion of the aircraft includes at least a portion of the electrical conductor.

3. The aircraft propulsion system of claim 2 wherein the electrical conductor comprises an electrical insulation.

4. The aircraft propulsion system of claim 3 wherein the electrical insulation is sized to prevent partial discharge at maximum voltage of the electrical power source at the ambient air pressure.

5. The aircraft propulsion system of claim 3 wherein the electrical insulation is sized to prevent partial discharge at maximum altitude of a flight envelope of the aircraft propulsion system.

6. The aircraft propulsion system of claim 5 wherein the voltage regulator is configured to regulate the electrical power by controlling the voltage provided to electric machine to prevent partial discharge throughout the flight envelope.

7. The aircraft propulsion system of claim 1 further comprising an ambient air pressure sensor operably coupled to the voltage regulator.

8. The aircraft propulsion system of claim 7 wherein the ambient air pressure sensor is an altimeter.

9. The aircraft propulsion system of claim 1 further comprising an electrical conductor connecting the voltage regulator to the electric machine, and wherein the electrical conductor is exposed to atmospheric pressure and the ambient air pressure is the current atmospheric pressure.

10. The aircraft propulsion system of claim 1 wherein the electric power source is one of an AC or DC electric power source.

11. The aircraft propulsion system of claim 1 wherein the electric machine is at least one of an AC or DC motor.

12. The aircraft propulsion system of claim 1 wherein the propeller comprises multiple propellers.

13. The aircraft propulsion system of claim 12 wherein the electric machine comprises multiple electric machines, where each of the multiple propellers being rotatably driven by a different one of the multiple electric machines.

14. The aircraft propulsion system of claim 13 where the voltage regulator is electrically coupled to all of the multiple electric machines.

15. The aircraft propulsion system of claim 13 wherein the voltage regulator comprises multiple voltage regulators, with each of the multiple electric machines being electrically coupled to a different one of the multiple voltage regulators.

16. The aircraft propulsion system of claim 1 wherein the electric power source comprises at least one of a combustion engine with generator or an electrical storage device.

17. The aircraft propulsion system of claim 1 wherein the voltage regulator comprises an inverter or a converter.

18. A method of operating an electric distribution system having an electrical conductor supplying electricity to an electric machine rotationally driving a propeller in an aircraft, the method comprising:

sensing ambient air pressure of the electrical conductor; and

controlling the voltage at the electrical conductor based on the sensed ambient air pressure.

19. The method of claim 18 wherein the controlling the voltage comprises controlling the voltage to prevent partial discharge from the electrical conductor based on the sensed ambient air pressure.

20. The method of claim 19 wherein the sensed ambient air pressure is atmospheric pressure.