Electric system architecture for more-electric engine accessories

1. An electric system comprising:

a flux regulated permanent magnet generator;

a first engine accessory that includes a first induction motor;

first and second power buses connected to provide power from the flux regulated permanent magnet generator to the first engine accessory; and

a voltage regulator that controls a magnetic flux present in the flux regulated permanent magnet generator to control an output of the flux regulated permanent magnet generator to maintain a constant voltage-to-frequency ratio.

2. The electric system of claim 1 , wherein the electric system further comprises:

a sensor that senses an output condition indicative of the output of the flux regulated permanent magnet generator, wherein the voltage regulator controls the output of the flux regulated permanent magnet generator based upon the output condition.

3. The electric system of claim 2 , wherein the electric system further comprises:

an auxiliary permanent magnet generator configured to provide power to the voltage regulator, wherein the auxiliary permanent magnet generator and the flux regulated permanent magnet generator are driven by a common shaft.

4. The electric system of claim 2 , wherein the sensor comprises a current sensor and a voltage sensor.

5. The electric system of claim 1 , further comprising:

a gearbox; and

a wound field synchronous generator, wherein the gearbox drives the wound field synchronous generator through a first shaft, and wherein the gearbox drives the flux regulated permanent magnet generator through a second shaft.

6. The electric system of claim 5 , wherein the flux regulated permanent magnet generator and the wound field synchronous generator are driven by a gas turbine engine.

7. The electric system of claim 1 , wherein the electric system further comprises:

a load management module configured to control power from the first and second power buses to the first engine accessory.

8. The electric system of claim 7 , wherein the electric system further comprises a second engine accessory that includes a second induction motor.

9. The electric system of claim 8 , wherein the load management module includes a plurality of solid state power controllers that control power provided from the first and second power buses to the first and second engine accessories.

10. A method comprising:

driving, by a gas turbine, a flux regulated permanent magnet generator;

providing, by the flux regulated permanent magnet generator, output power to a plurality of engine accessories through first and second power buses, wherein the output power has a power frequency and a power voltage; and

controlling, using a voltage regulator, a magnetic flux present within the flux regulated permanent magnet generator to maintain a constant ratio between the power voltage and the power frequency.

11. The method of claim 10 , further comprising:

driving, by the gas turbine, a wound field synchronous generator; and

providing, by the wound field synchronous generator, load power to a plurality of aircraft loads.

12. The method of claim 10 , further comprising:

driving the plurality of engine accessories using a plurality of induction motors; and

controlling the output power from the first and second power buses to the plurality of induction motors using a plurality of solid state power controllers.

13. The method of claim 10 , further comprising:

providing, by an auxiliary permanent magnet generator, power to the voltage regulator.

14. The method of claim 13 , wherein driving, by the gas turbine, the flux regulated permanent magnet generator comprises driving the flux regulated permanent magnet generator using a gearbox, wherein the flux regulated permanent magnet generator and the auxiliary permanent magnet generator are driven by a common shaft.

15. The method of claim 10 , further comprising:

sensing a sensed condition of the output power of the flux regulated permanent magnet generator;

wherein controlling, using the voltage regulator, the magnetic flux present within the flux regulated permanent magnet generator comprises controlling the magnetic flux present within the flux regulated permanent magnet generator based upon the sensed condition.