AC electrical power system for a vehicle
View Patent ↗An AC electrical system for a vehicle and methods of operating the same are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first electric machine to the first AC bus and a second electrical channel electrically couples the second electric machine to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first and second electrical channels so that electrical power generated by one electric machine can be converted and shared with the other electric machine and electrical loads of the other channel.
1. An alternating current (AC) electrical system for a vehicle, comprising:
a first electric machine mechanically coupled with a first spool of a gas turbine engine;
a second electric machine mechanically coupled with a second spool of the gas turbine engine;
a first AC bus;
a second AC bus;
a direct current (DC) bus system electrically coupled to at least one of the first AC bus or the second AC bus;
a first electrical channel electrically coupling the first electric machine to the first AC bus, wherein the first electrical channel has a first load line that electrically couples a first load AC/DC converter to the DC bus system and the first load AC/DC converter to a first electrical load;
a second electrical channel electrically coupling the second electric machine to the second AC bus, wherein the second electrical channel has a second load line that electrically couples a second load AC/DC converter to the DC bus system and the second load AC/DC converter to a second electrical load;
one or more connection links selectively electrically coupling the first electrical channel and the second electrical channel; and
one or more power converters operable to convert electrical power generated by the second electric machine and transfer the electrical power from the second electrical channel, across the one or more connection links to the first electrical channel, and onward to the first electric machine.
2. The AC electrical system of claim 1 , wherein the one or more connection links includes an AC converter link for selectively electrically coupling the first AC bus and the second AC bus, the AC converter link including an AC/AC converter, wherein the electrical power generated by the second electric machine is transferred from the second electrical channel to the first electrical channel through the AC/AC converter.
3. The AC electrical system of claim 2 , wherein the AC/AC converter is one of a matrix converter and a cycloconverter.
4. The AC electrical system of claim 1 , wherein the one or more power converters comprise a first AC/DC converter and a second AC/DC converter, the first AC/DC converter being a bidirectional AC/DC converter, the AC electrical system further comprising:
wherein the first electrical channel electrically couples the first AC bus to the first AC/DC converter and the first AC/DC converter to the DC bus system, and
wherein the second electrical channel electrically couples the second AC bus to the second AC/DC converter and the second AC/DC converter to the DC bus system.
5. The AC electrical system of claim 4 , wherein the electrical power generated by the second electric machine is transferred between the second electrical channel and the first electrical channel through the second AC/DC converter and the first AC/DC converter.
6. The AC electrical system of claim 4 , wherein the electrical power generated by the second electric machine is transferred between the second electrical channel and the first electrical channel through the second AC/DC converter, to the DC bus system, and onward through the first AC/DC converter.
7. The AC electrical system of claim 4 , wherein the DC bus system includes a first DC bus positioned along the first electrical channel and a second DC bus positioned along the second electrical channel, and wherein the one or more connection links include a DC bus link for selectively electrically coupling the first DC bus and the second DC bus of the DC bus system.
8. The AC electrical system of claim 7 , wherein the electrical power generated by the second electric machine is transferred between the second electrical channel and the first electrical channel through the DC bus link.
9. The AC electrical system of claim 4 , wherein the second electrical channel has a second secondary line that electrically connects the second AC bus with the second load line at a point between the second load AC/DC converter and the second electrical load.
10. The AC electrical system of claim 9 , wherein the electrical power generated by the second electric machine is directed from the second AC bus, through the second load line to the point between the second load AC/DC converter and the second electrical load, and onward through the second load AC/DC converter to the DC bus system.
11. The AC electrical system of claim 9 , wherein the first electrical channel has a first secondary line that electrically connects the first AC bus with the first load line at a point between the first load AC/DC converter and the first electrical load.
12. The AC electrical system of claim 4 , wherein the DC bus system includes a single DC bus, and wherein the one or more connection links include the single DC bus for selectively electrically coupling the first electrical channel and the second electrical channel.
13. The AC electrical system of claim 4 , wherein the DC bus system is one of a voltage DC bus and a current DC bus.
14. The AC electrical system of claim 1 , further comprising one or more processors being configured to:
cause electrical power generated by the second electric machine to be transferred across at least one of the one or more connection links from the second electrical channel to the first electrical channel and to the first electric machine based at least in part on a power share split for a power assist operation.
15. The AC electrical system of claim 1 , wherein:
i) the first spool is a high pressure spool and the second spool is a low pressure spool; or
ii) the first spool is the low pressure spool and the second spool is the high pressure spool.
16. The AC electrical system of claim 1 , wherein the first spool is an intermediate pressure spool and the second spool is one of a low pressure spool and a high pressure spool of the gas turbine engine.
17. A method, comprising:
transferring electrical power generated by a second electric machine mechanically coupled with a second spool of a gas turbine engine to a first electric machine mechanically coupled with a first spool of the gas turbine engine over an alternating current (AC) electrical system of a vehicle, and
wherein the transferring comprises directing the electrical power from the second electric machine along a second electrical channel to a second AC bus positioned along the second electrical channel, through one or more connections links to a first electrical channel, and to the first electric machine through a first AC bus,
wherein the one or more connection links include an AC converter link for selectively electrically coupling the first AC bus and the second AC bus, the AC converter link including an AC/AC converter, wherein the electrical power generated by the second electric machine is transferred in the AC phase directly between the first electrical channel and the second electrical channel through the AC/AC converter.
18. The method of claim 17 , wherein the transferring of the electrical power further comprises:
transferring the electrical power generated by the second electric machine from the second electrical channel to the first electrical channel through a second AC/DC converter and a first AC/DC converter.
19. An alternating current (AC) electrical system for a vehicle, comprising:
a first electric machine mechanically coupled with a first spool of a gas turbine engine;
a second electric machine mechanically coupled with a second spool of the gas turbine engine;
a first AC bus;
a second AC bus;
a first electrical channel electrically coupling the first electric machine to the first AC bus;
a second electrical channel electrically coupling the second electric machine to the second AC bus;
an AC converter link selectively electrically coupling the first electrical channel and the second electrical channel; and
one or more AC/AC power converters operable to convert electrical power generated by the second electric machine and transfer the electrical power in the AC phase directly from the second electrical channel, across the AC converter link to the first electrical channel, and onward to the first electric machine.
20. The AC electrical system of claim 19 , further comprising a first AC/DC converter and a second AC/DC converter, the first AC/DC converter being a bidirectional AC/DC converter, the AC electrical system further comprising:
a direct current (DC) bus system; and
wherein the first electrical channel electrically couples the first AC bus to the first AC/DC converter and the first AC/DC converter to the DC bus system, and
wherein the second electrical channel electrically couples the second AC bus to the second AC/DC converter and the second AC/DC converter to the DC bus system.