Doubly-fed, variable-speed, dual-voltage AC generation and distribution systems
View Patent ↗A generation and distribution system includes an adjustable-speed prime mover and a doubly-fed asynchronous alternating-current (AC) generator driven by the prime mover and having a first poly-phase circuit, e.g., a stator, and a second poly-phase circuit, e.g., a rotor. The system further includes a first AC bus electrically coupled to the first poly-phase circuit configured to deliver AC power at a first AC voltage to multiple loads, and a second AC bus connected to the second poly-phase circuit configured to deliver AC power at a second AC voltage to another group of loads, the second AC voltage being lower than the first. The system includes a poly-phase transformer having first windings electrically coupled to the first AC bus and having second windings electrically coupled to the second AC bus, and a poly-phase AC-to-AC electronic converter circuit electrically coupled between the second poly-phase circuit and the second AC bus.
1. An electric generation and distribution system, comprising:
a prime mover configured for adjustable speed operation;
a doubly-fed, asynchronous alternating-current (AC) induction generator driven by the prime mover and having a first poly-phase circuit and a second poly-phase circuit;
a first AC distribution bus electrically coupled to the first poly-phase circuit and configured to deliver AC power at a first AC voltage to a first plurality of loads;
a second AC distribution bus electrically coupled to the second poly-phase circuit and configured to deliver AC power at a second AC voltage to a second plurality of loads, the second AC voltage being lower than the first AC voltage;
a poly-phase transformer having first windings electrically coupled to the first AC distribution bus and having second windings electrically coupled to the second AC distribution bus; and
a poly-phase AC-to-AC electronic converter circuit electrically coupled between the second poly-phase circuit and the second AC distribution bus.
2. The electric generation and distribution system of claim 1 , wherein the doubly-fed asynchronous AC generator is one of the following:
a wound-rotor induction generator with slip rings; and
a wound-rotor induction generator with brushless excitation.
3. The electric generation and distribution system of claim 1 , wherein the AC-to-AC electronic converter circuit is an indirect converter.
4. The electric generation and distribution system of claim 1 , wherein the AC-to-AC electronic converter circuit is configured to convert AC power between a variable-voltage, variable-frequency, AC voltage at the second poly-phase circuit and a substantially fixed frequency AC voltage at the second AC distribution bus.
5. The electric generation and distribution system of claim 1 , further comprising:
a second prime mover configured for adjustable speed operation;
a second doubly-fed asynchronous alternating-current (AC) induction generator driven by the second prime mover and having a third poly-phase circuit electrically coupled to the first AC distribution bus and a fourth poly-phase circuit; and
a second poly-phase AC-to-AC converter circuit electrically coupled between the fourth poly-phase circuit and the second AC distribution bus.
6. A method of configuring an electric generation and distribution system, the method comprising:
configuring a prime mover for driving a doubly-fed asynchronous alternating current (AC) induction generator, the doubly-fed asynchronous AC induction generator having a first poly-phase circuit and a second poly-phase circuit;
electrically coupling a first AC distribution bus to the first poly-phase circuit and to a first plurality of loads, so as to deliver AC power at a first AC voltage to the first plurality of loads;
electrically coupling a second AC distribution bus to the second poly-phase circuit and to a second plurality of loads, so as to deliver AC power at a second AC voltage to the second plurality of loads;
electrically coupling first windings of a poly-phase transformer to the first AC distribution bus and electrically coupling second windings of the poly-phase transformer to the second AC distribution bus, so as to deliver AC power at a second AC voltage to the second AC distribution bus, the second AC voltage being lower than the first AC voltage; and
electrically coupling a poly-phase AC-to-AC electronic converter circuit between the second poly-phase circuit and the second AC distribution bus.
7. The method of claim 6 , wherein the doubly-fed asynchronous AC generator is one of the following:
a wound-rotor induction generator with slip rings; and
a wound-rotor induction generator with brushless excitation.
8. The method of claim 6 , wherein the AC-to-AC electronic converter circuit is an indirect converter.
9. The method of claim 6 , wherein the AC-to-AC electronic converter circuit is configured to convert AC power between a variable-voltage, variable-frequency, AC voltage at the second poly-phase circuit and a substantially fixed frequency AC voltage at the second AC distribution bus.
10. The method of claim 6 , further comprising:
configuring a second prime mover for driving a second doubly-fed asynchronous alternating current (AC) induction generator, the second doubly-fed asynchronous AC induction generator having a third poly-phase circuit and a fourth poly-phase circuit;
electrically coupling the third poly-phase circuit to the first AC distribution bus; and
electrically coupling a second poly-phase AC-to-AC converter circuit between the fourth poly-phase circuit and the second AC distribution bus.
11. A method of operating an electric generation and distribution system, the method comprising:
driving a doubly-fed asynchronous alternating current (AC) induction generator with a prime mover, the doubly-fed asynchronous AC induction generator having a first poly-phase circuit and a second poly-phase circuit;
coupling AC power from the first poly-phase circuit to a first AC distribution bus, without voltage conversion, and from the first AC distribution bus to a first plurality of loads, so as to deliver AC power at a first AC voltage to the first plurality of loads;
converting AC power from the second poly-phase circuit to a second AC voltage, using a poly-phase AC-to-AC electronic converter circuit, and coupling the second poly-phase circuit to a second AC distribution bus, wherein the second AC voltage is lower than the first AC voltage;
transforming AC power from the first poly-phase circuit to the second AC voltage, using a poly-phase transformer having first windings electrically coupled to the first AC distribution bus and second windings electrically coupled to the second AC distribution bus; and
delivering power at the second AC voltage to a second plurality of loads, using the second AC distribution bus.
12. The method of claim 11 , wherein die doubly-fed asynchronous AC generator is one of the following:
a wound-rotor induction generator with slip rings; and
a wound rotor induction generator with brushless excitation.
13. The method of claim 11 , wherein the AC-to-AC electronic converter circuit is an indirect converter.
14. The method of claim 11 , wherein the AC-to-AC electronic converter circuit is configured to convert AC power between a variable-voltage, variable-frequency, AC voltage at the second poly-phase circuit to a substantially fixed frequency AC voltage at the second AC distribution bus.
15. The method of claim 11 , further comprising:
driving a second doubly-fed asynchronous alternating current (AC) induction generator with a second prime mover, the second doubly-fed asynchronous AC induction generator having a third poly-phase circuit and a fourth poly-phase circuit;
coupling AC power from the third poly-phase circuit to the first AC distribution bus, without voltage conversion;
converting AC power from the fourth poly-phase circuit to the second AC voltage, using a second poly-phase AC-to-AC electronic converter circuit, and coupling the converted AC power to the second AC distribution bus.