Generator starter of a turbomachine with asynchronous multi-winding electric machine
A generator starter of a turbomachine, including an asynchronous electric machine configured so as to operate in motor mode during a starting phase of the turbomachine while being supplied by an electrical source, and so as to operate in generator mode after the starting phase of the turbomachine in order to supply an electrical load. An inverter is arranged between the electrical source and the asynchronous machine with at least two alternating current terminals coupled to the asynchronous machine, and a control unit for the inverter configured to supply the asynchronous machine with a starting current in motor mode and a magnetisation current in generator mode. The asynchronous machine includes at least one first stator winding connected to the alternating current terminals to be supplied with the starting current in motor mode and with the magnetisation current in generator mode, and at least one second stator winding connected to the electrical load in generator mode.
1. A turbomachine starter-generator, comprising:
an asynchronous electric machine configured so as to operate in a motor mode during a starting phase of a turbomachine while being power supplied by an electrical source, and so as to operate in a generator mode after the starting phase of the turbomachine in order to supply power to an electrical load;
an inverter arranged between the electrical source and the asynchronous machine, the inverter having at least two AC terminals coupled to the asynchronous machine and at least two DC terminals coupled to a DC bus;
an inverter control unit configured such that the inverter outputs onto the at least two AC terminals a starting current in the motor mode and a magnetisation current in the generator mode; and
at least one first stator winding connected to the at least two AC terminals of the inverter in order to be supplied with the starting current in the motor mode and with the magnetisation current in generator mode, and at least one second stator winding connected to the electrical load in the generator mode,
wherein the inverter control unit is configured in the generator mode such that the inverter supplies the magnetisation current without being driven by said electrical source or another electrical source while being controlled from a voltage measurement at the electrical load and a voltage measurement on the DC bus, an amplitude and a frequency of the magnetisation current being controlled from the voltage measurement at the electrical load and the voltage measurement on the DC bus so as to balance active and reactive powers of the asynchronous electric machine.
2. The starter-generator according to claim 1 , wherein the at least one second stator winding is disconnected from the electrical load in the motor mode.
3. The starter-generator according to claim 1 , further comprising a converter between the inverter and the electrical source.
4. The starter-generator according to claim 3 , wherein the electrical source is an AC source, and the converter is an AC-DC converter.
5. The starter-generator according to claim 3 , wherein the converter is a two-directional converter and wherein the electrical source is a rechargeable source to which the asynchronous machine outputs energy through the at least one first stator winding in the generator mode.
6. The starter-generator according to claim 1 , wherein the electrical load is an onboard electrical network.
7. The starter-generator according to claim 1 , wherein the electrical load is a DC load and further comprising a rectifier arranged between the at least one second stator winding and the DC load.
8. The starter-generator according to claim 7 , wherein the rectifier is integrated into the asynchronous machine.
9. The starter-generator according to claim 1 , further comprising an auxiliary converter configured so as to load the DC bus in a priming phase of the generator mode and to be deactivated once the generator mode is established.
10. The starter-generator according to claim 1 , wherein the at least one second stator winding comprises several sets of windings each comprising at least one stator winding, the sets being out of phase by an electrical angle.
11. The starter-generator according to claim 10 , wherein the at least one second stator winding comprises two sets of three-phase stator windings out-of-phase by 30°.
12. The starter-generator according to claim 1 , wherein the at least one first stator winding and the at least one second stator winding are three-phase windings.
13. The starter-generator according to claim 1 , wherein the at least one first stator winding and the at least one second stator winding have a different number of turns.
14. The starter-generator according to claim 1 , wherein the rotor of the asynchronous machine is of the squirrel cage type.
15. The starter-generator according to claim 1 , further comprising an isolation contactor located between the inverter and the electrical source, said isolation contactor being capable of being controlled to disconnect the inverter from the electrical source in the generator mode.
16. A turbomachine comprising the starter-generator according to claim 1 .