High torque starter/generator with low input voltage
View Patent ↗An apparatus includes a plurality of starter/generator subsystems connected in parallel to a voltage distribution bus and to an input power supply. Each of the subsystems includes a starter/generator unit (SGU) for providing torque for starting an engine when the apparatus is operated in an engine start mode, and for generating power when the apparatus is operated in a generator mode. In an embodiment, each subsystem includes a power conversion unit (PCU) connected to the respective SGU, and each PCU includes an inverter section for rectifying voltage generated by the SGU when the apparatus is operated in the generator mode and may provide AC excitation voltage to operate the SGU as a motor to support the engine start mode.
1. An apparatus comprising:
a plurality of starter/generator subsystems connected in parallel to a voltage distribution bus,
wherein each of the subsystems further includes
a first power connection for receiving power when the apparatus is operated in an engine start mode and for providing power when the apparatus is operated in a generator mode, said first power connection configured for a DC voltage lower than that of the voltage distribution bus,
a second power connection for providing power when the apparatus is operated in the generator mode, said second power connection configured for AC voltage, and
a starter/generator unit (SGU) for providing torque for starting an engine when the apparatus is operated in the engine start mode, and for generating power when the apparatus is operated in the generator mode.
2. An apparatus according to claim 1 , wherein
each subsystem further includes a power conversion unit (PCU) connected to the respective SGU,
each PCU includes an inverter section for rectifying voltage generated by the SGU when the apparatus is operated in the generator mode, and
each PCU is connected to the respective second power connection for providing AC output power when the apparatus is operated in the generator mode.
3. An apparatus according to claim 2 , wherein the inverter section provides AC voltage to excite the SGU when the apparatus is operated in the engine start mode.
4. An apparatus according to claim 2 , wherein each PCU further includes a converter section configured to upconvert the voltage of the input power supply to a voltage suitable to support engine starting when the apparatus is operated in the engine start mode, and downconvert the voltage generated by the SGU when the apparatus is operated in the generator mode.
5. An apparatus according to claim 4 , wherein the apparatus is configured to supply power to an aircraft when operated in the generator mode, and the converter section is configured to downconvert AC voltage generated by the SGU to a voltage suitable for aircraft electrical loads when the apparatus is operated in the generator mode.
6. An apparatus according to claim 1 , wherein the apparatus is configured for starting an aircraft engine when operated in the engine start mode.
7. An apparatus according to claim 6 , wherein the apparatus is also configured for generating power for aircraft electrical loads when the apparatus is operated in the generator mode.
8. An apparatus comprising:
a first starter/generator subsystem and a second starter/generator subsystem connected in parallel to a voltage distribution bus and configured for connection to an input power supply,
wherein each of the starter/generator subsystems further includes
a first power connection for receiving power when the apparatus is operated in an engine start mode and for providing power when the apparatus is operated in a generator mode, said first power connection configured for a DC voltage lower than that of the voltage distribution bus,
a second power connection for providing power when the apparatus is operated in the generator mode, said second power connection configured for AC voltage,
a starter/generator unit (SGU) for providing torque for starting an engine when the apparatus is operated in an engine start mode, and for generating power when the apparatus is operated in a generator mode, and
a power conversion unit (PCU) connected to the SGU and connected to the second power connection for providing AC output power when the apparatus is operated in the generator mode, each PCU including
an inverter section for rectifying voltage generated by the SGU when the apparatus is operated in the generator mode, and
a converter section configured to upconvert the voltage of the input power supply to a voltage suitable to support engine starting when the apparatus is operated in the engine start mode, and downconvert the voltage generated by the SGU when the apparatus is operated in the generator mode,
and wherein the first and second starter/generator subsystems are coupled to a first aircraft engine having a required starting torque, each of the starter/generator subsystems providing approximately half the required starting torque.
9. An apparatus according to claim 8 , further comprising:
a third starter/generator subsystem and a fourth starter/generator subsystem connected in parallel to the voltage distribution bus and configured for connection to the input power supply, wherein the third and fourth starter/generator subsystems are coupled to a second aircraft engine having a required starting torque, each of the third and fourth starter/generator subsystems providing approximately half the required starting torque; and
a fifth starter/generator subsystem coupled to an auxiliary power unit (APU) for starting the first and second aircraft engines, the fifth starter/generator subsystem including a starter/generator unit connected to a power conversion unit including an inverter section,
the apparatus thereby forming a parallel connected starter/generator system for a set of two aircraft engines.
10. An apparatus according to claim 9 , wherein the inverter section of the fifth starter/generator subsystem provides AC output power when the apparatus is operated in the generator mode.
11. An apparatus according to claim 8 , wherein the apparatus is configured to supply power to an aircraft when operated in the generator mode, and the converter section is configured to downconvert AC voltage generated by the SGU to a voltage suitable for aircraft loads when the apparatus is operated in the generator mode.
12. An apparatus according to claim 8 , wherein the inverter section provides AC voltage to excite the SGU when the apparatus is operated in the engine start mode.
13. An apparatus according to claim 8 , wherein the input power supply comprises one or more aircraft batteries.
14. An apparatus according to claim 13 , wherein the starter/generator subsystems and the aircraft batteries are connected via a DC low voltage distribution bus.
15. An apparatus comprising:
a first starter/generator subsystem and a second starter/generator subsystem connected in parallel to a voltage distribution bus and configured for connection to an input power supply,
wherein each of the first and second starter/generator subsystems includes
a starter/generator unit (SGU) for providing torque for starting an engine when the apparatus is operated in an engine start mode, and for generating power when the apparatus is operated in a generator mode, and
a power conversion unit (PCU) connected to the SGU, each PCU including
an inverter section for rectifying voltage generated by the SGU when the apparatus is operated in the generator mode, and
a converter section configured to upconvert the voltage of the input power supply to a voltage suitable to support engine starting when the apparatus is operated in the engine start mode, and downconvert the voltage generated by the SGU when the apparatus is operated in the generator mode,
and wherein the first and second starter/generator subsystems are coupled to a first aircraft engine having a required starting torque, each of the starter/generator subsystems providing approximately half the required starting torque;
a third starter/generator subsystem and a fourth starter/generator subsystem connected in parallel to the voltage distribution bus and configured for connection to the input power supply, wherein the third and fourth starter/generator subsystems are coupled to a second aircraft engine having a required starting torque, each of the third and fourth starter/generator subsystems providing approximately half the required starting torque; and
a fifth starter/generator subsystem coupled to an auxiliary power unit (APU) for starting the first and second aircraft engines, the fifth starter/generator subsystem including a starter/generator unit connected to a power conversion unit including an inverter section,
the apparatus thereby forming a parallel connected starter/generator system for a set of two aircraft engines.
16. An apparatus according to claim 15 , wherein the apparatus is configured to supply power to an aircraft when operated in the generator mode, and the converter section is configured to downconvert AC voltage generated by the SGU to a voltage suitable for aircraft loads when the apparatus is operated in the generator mode.
17. An apparatus according to claim 15 , wherein the inverter section provides AC voltage to excite the SGU when the apparatus is operated in the engine start mode.
18. An apparatus according to claim 15 , wherein the input power supply comprises one or more aircraft batteries.
19. An apparatus according to claim 18 , wherein the starter/generator subsystems and the aircraft batteries are connected via a DC low voltage distribution bus.
20. An apparatus according to claim 15 , wherein the inverter section of the fifth starter/generator subsystem provides AC output power when the apparatus is operated in the generator mode.