Methods and apparatus for ride-through operation of a complementary device to a transient power source

• US 20060066104A1
• Filed: 09/30/2004
• Published: 03/30/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Melfi, Michael J.
• Granted Patent: US 7,358,620 B2
• Time in Patent Office: Days
• US Class Current: 290/1.A
• CPC Class Codes: H02J 9/066 characterised by the use of dynamo-electric machines H02J9/08 takes precedence
• CPC Class Codes: H02K 7/025 for power storage
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

In accordance with certain exemplary embodiments, the present technique provides methods and apparatus for providing operating power to a complementary device to an induction device based uninterruptible power source (UPS) via a direct current (dc) bus. In one embodiment, the UPS includes a flywheel that stores kinetic energy during conventional operating conditions, e.g., external power is available. During such operating condition, the external power operates the induction device as an induction motor. However, when external power is lost, i.e., a transient operating condition, power conversion circuitry of the UPS provides ac power to the induction device such that the induction device operates above its synchronous speed and, as such, acts as an induction generator. However to improve the operating of the exemplary UPS, it includes second power conversion circuitry that converts both generated and received power to a power level that is desirable to complementary device cooperating with the induction device.

Claims

1. A power supplying apparatus, comprising:

a direct current (dc) bus configured to receive dc power that is rectified from an alternating current (ac) power source;

first power conversion circuitry that is electrically coupled to the dc bus and that is configured to convert inputted power between a first ac power at a variable frequency and dc power;

second power conversion circuitry that is electrically coupled to the dc bus and that is configured to convert dc power to a second ac power;

an electrical machine, comprising;

a kinetic energy storage device;

a stator having a rotor chamber and electrical conductors configured to receive the first ac power; and

a rotor disposed in the rotor chamber and mechanically coupled to the kinetic energy storage device, wherein the first power conversion circuitry is configured to provide first ac power at the variable frequency to generate power from the electrical machine; and

a complementary device that is in cooperation with the electrical machine and that is configured receive the second ac power from the second power conversion circuitry.

2. The power supplying apparatus as recited in claim 1, wherein the kinetic energy storage device comprises a flywheel.

3. The power supplying apparatus as recited in claim 1, wherein the complementary device comprises a magnetic bearing device.

4. The power supplying apparatus as recited in claim 1, wherein the complementary device comprises a lubrication device.

5. The power supplying apparatus as recited in claim 1, wherein the complementary device comprises a cooling device.

6. The power supplying apparatus as recited in claim 1, comprising a sensor configured to determine a rotation rate of the rotor or the kinetic energy storage device, wherein the variable frequency is based on the rotation rate.

7. A system for providing a transient power supply, comprising:

a direct current (dc) bus configured to route dc power;

power conversion circuitry electrically coupled to the dc bus and configured to convert dc power to a first alternating current (ac) power;

a power source configured to provide second ac power at a selectable frequency and electrically coupled to the dc bus;

an induction device, comprising;

a kinetic energy storage device;

a stator having a rotor chamber and electrical conductors configured to receive the second ac power; and

a rotor disposed in the rotor chamber and mechanically coupled to the kinetic energy storage device, wherein the power source is configured to provide second ac power at the selected frequency to generate power from the induction device during a transient power condition; and

a complementary device configured to cooperate with the induction device and configured to receive first ac power from the power conversion circuitry.

8. The system as recited in claim 7, wherein the kinetic energy storage device comprises a rotatable flywheel.

9. The system as recited in claim 7, wherein the complementary device comprises a magnetic bearing device.

10. The system as recited in claim 7, wherein the complementary device comprises a cooling device.

11. The system as recited in claim 7, wherein the complementary device comprises a lubrication device.

12. A system for providing a transient power supply, comprising:

a rotatable kinetic energy storing device;

first power conversion circuitry configured to convert inputted power between a direct current (dc) power and a first alternating current (ac) power and to receive the first ac power from an external power source;

a dc bus electrically coupled to the first power conversion circuitry;

second power conversion circuitry that is electrically coupled to the dc bus and that is configured to convert inputted power between the dc power and a second alternating current (ac) power at a selectable frequency;

third power conversion circuitry that is electrically coupled to the dc bus and that is configured to convert the dc power to a third ac power;

a dc bus electrically coupling the first and second power conversion circuitry; and

an electrical machine, comprising;

a stator having a rotor chamber and a plurality of electrical conductors configured to receive the second ac power from the second power conversion circuitry; and

a rotor disposed in the rotor chamber and mechanically coupled to the rotatable kinetic energy storage device, wherein the selectable frequency is based on the operating parameter of the electrical machine and facilitates power generation of a third ac power by the electrical machine; and

a complementary deice configured to facilitate operation of the electrical machine and to receive ac power to operate from the third power conversion circuitry.

13. The system as recited in claim 12, wherein the kinetic energy storing device comprises a flywheel.

14. The system as recited in claim 12, wherein the complementary device comprises a cooling device, a magnetic device, a lubricant device or a monitoring device.

15. The system as recited in claim 12, comprising a sensor configured to determine a rotational rate of the kinetic energy storage device or the rotor.

16. The system as recited in claim 12, comprising a housing, wherein the kinetic energy storage device, the complementary device and the electric machine are disposed in the housing.

17. The system as recited in claim 12, wherein the electrical machine comprises an induction machine.

18. A system for providing a transient power supply, comprising:

first power conversion circuitry electrically coupled to a first bus configured to transmit a first alternating current (ac) power at a first frequency, the first power conversion circuitry being configured to convert a first inputted power between the first ac power and a dc power;

second power conversion circuitry electrically coupled to the first power conversion circuitry via a second bus configured to transmit the dc power, the second power conversion circuitry being configured to convert a second input power between a second ac power at a second frequency that is variable and the dc power;

an electrical machine, comprising;

a rotatable flywheel;

a stator having a rotor chamber and a plurality of stator windings configured to receive the second ac power; and

a rotor disposed in the rotor chamber and mechanically coupled to the rotatable flywheel;

a sensor configured to sense an operating parameter of the electrical machine, wherein the second frequency is based on the operating parameter and facilitates the generation of a third ac power at the second frequency by the electric machine during operation; and

third power conversion circuitry coupled to the second bus and configured to convert the dc power to a fourth ac power at a third frequency; and

a complementary device configured to receive the fourth ac power to operate.

19. The system as recited in claim 18, wherein the second frequency is based on the rotational rate of the rotatable flywheel or the rotor.

20. The system as recited in claim 18, comprising a housing, wherein at least two of the first, second and third frequencies are the same.

21. The system as recited in claim 18, wherein at least two of the first, second and third frequencies are different.

22. The system as recited in claim 18, wherein the complementary device comprises, a cooling device, a monitoring device, a lubrication device or a magnetic bearing device.

23. The system as recited in claim 18, wherein the rotor comprises a squirrel cage rotor.

24. The system as recited in claim 18, wherein the first bus is configured to receive the first ac power from an external power source.

25. A method providing operating power to a complementary device to an electrical machine, comprising:

converting a provided power to a first alternating current (ac) power at a selectable frequency;

providing the first ac power to electrical conductors disposed in the electrical machine at the selectable frequency to produce generated ac power via the electrical machine;

converting the generated ac power to a generated dc power; and

converting the generated dc power to a second ac power to operate the complementary device.

26. The method as recited in claim 25, comprising routing the generated dc power and the provided dc power over a dc bus.

27. The method as recited in claim 25, comprising cooling the electrical machine via the complementary device.

28. The method as recited in claim 25, comprising circulating a lubricant with respect to the electrical machine via the complementary device.

29. The method as recited in claim 25, determining an operating parameter of the electrical machine and selecting the selectable frequency based on the operating parameter.

30. The method as recited in claim 25, comprising conditioning the generated power to match the frequency and voltage of an external alternating current power configured to provide operating power to a load during operation.

31. A system for providing a transient power supply, comprising:

means for converting a provided power to a first alternating current (ac) power at a selectable frequency;

means for generating a generated power from an electrical machine by converting stored kinetic energy into electrical energy in response to providing the first ac power at the selected frequency to the electrical machine;

means for routing the generated power to the complementary device; and

means for converting the generated power to a second ac power to operate the complementary device.