Fixed frequency electrical generation system and corresponding control procedure

1. Fixed frequency electrical generation system that can be placed at the variable load engine output, characterised in that it includes:

an initial stage ( 30 ), which is a permanent magnet generator that provides energy to said system, making it autonomous,

a secondary stage ( 21 ), which is an excitation stage that controls the magnetisation of a third stage,

this third stage ( 24 ), which is a main generator, is the electrical energy production power stage,

in that the rotors ( 22 and 25 ) of the secondary stage ( 21 ) and the third stage ( 24 ) are integrated into a first shaft ( 27 ), the stator ( 26 ) of the third stage ( 24 ) supplies the output voltage (V sm ), in that the rotor ( 31 ) of the first stage ( 30 ) is integrated into a second shaft ( 33 ), in that at least one oil pump of the cooling circuit ( 34 ) is integrated into a third shaft ( 35 ), and in that these three shafts ( 27 , 33 , and 35 ) are driven by the input shaft ( 36 ), which is the engine shaft, using gears ( 37 , 38 , 39 , and 40 ).

2. System according to claim 1 , in which the rotor ( 31 ) of the permanent magnet generator ( 30 ) is driven by the shaft of the engine ( 36 ), and its stator ( 32 ) powers an external control unit ( 41 ).

3. System according to claim 2 , in which the stator ( 23 ) of the exciter ( 21 ) is powered by variable frequency three-phase currents from a three-phase current inverter ( 43 ) of said external control unit ( 41 ).

4. System according to claim 3 , in which the rotor ( 25 ) of the main generator ( 24 ) is integrated with the rotor ( 22 ) of the exciter ( 21 ) and is driven by the shaft of the engine ( 36 ); its rotor windings are interconnected with those of the exciter.

5. System according to any of the previous claims, which includes an input shaft ( 36 ) that is driven in variable load and that converts the mechanical energy into electrical energy to rectify it in the form of three-phase voltages and currents to the stator ( 26 ) of the main stage ( 24 ), which are then distributed over an alternating current network.

6. System according to any of claims 1 to 4 , in which the stator ( 26 ) of the main stage ( 24 ) is powered by three-phase voltages and the stator ( 23 ) of the exciter ( 21 ) is short-circuited; the energy absorbed is electrical and the energy generated is mechanical.

7. System according to any of claims 1 to 4 , that includes a static converter that allows transferring the energy on the electrical network in a controlled manner.

8. System control procedure according to claim 5 , in which the voltage (V sm ) is controlled at the stator of the main stage ( 24 ), and that includes two adjustment loops:

an excitation current loop;

an output voltage loop.

9. System control procedure according to claim 5 , in which the frequency of the system is controlled, which includes:

an excitation frequency loop;

an output frequency loop.

10. Use of the system of the invention according to claim 1 , on an aircraft as an electrical generator and/or electrical engine.