Electric turbomachine

1. Turbomachinery comprising:

first and second sets of rotors of a contra-rotating compressor configured to operate on a working fluid;

combustion equipment configured to mix fuel with the working fluid and combust a mixture of the working fluid and the fuel;

first and second sets of electric motors coupled to the respective first and second rotors;

a common motor controller configured to:

control the first set of electric motors to impart rotational force on the first rotors; and

control the second set of electric motors to impart rotational force on the second rotors; and

a coupling arrangement arranged to couple adjacent rotors of the first and second sets of rotors to provide for fixed ratio synchronized contra-rotation of the first and second sets of rotors.

2. Turbomachinery according to claim 1 , wherein the turbomachinery comprises a turbine.

3. Turbomachinery according to claim 1 , wherein the coupling arrangement comprises a mechanical gearing arrangement, which mechanically couples rotors of the first set of rotors with an adjacent rotor of the second set of rotors.

4. Turbomachinery according to claim 3 , wherein the coupling arrangement comprises a contra-rotating epicyclic gearbox.

5. Turbomachinery according to claim 3 , wherein the coupling arrangement comprises a ring gear mounted to each of the first and second rotors and a pinion gear arranged to mesh with the ring gears.

6. Turbomachinery according to claim 1 , wherein each electric motor comprises a radial flux electric machine comprising a stator and a rotor.

7. Turbomachinery according to claim 6 , wherein the stator of each electric motor is provided radially inward of the rotor.

8. Turbomachinery according to claim 1 , wherein rotors of adjacent electric motors comprise a different number of magnetic poles relative to one another.

9. Turbomachinery according to claim 4 , wherein the contra-rotating epicyclic gearbox comprises a star gearbox.