Locomotive power train architecture

• US 7,304,445 B2
• Filed: 08/09/2005
• Issued: 12/04/2007
• Est. Priority Date: 08/09/2004
• Status: Active Grant

• Current Assignee: Railpower, LLC
• Original Assignee: Railpower Technologies Corp.
• Inventors: Donnelly, Frank Wegner
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US11/200,881
• Publication Number:
  US 20060061307A1
• Time in Patent Office: 847 Days
• Field of Search: 318/139, 318/108, 318140-149, 318/254, 105/50, 105/26.05, 290/4.R, 180/65.4, 180/65.2, 477/2, 477/15, 307/64, 307/67, 320/101, 323/207
• US Class Current: 318/108
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/53 in combination with an external power supply, e.g. from overhead contact lines
• CPC Class Codes: B60L 50/75 using propulsion power supplied by both fuel cells and batteries
• CPC Class Codes: B60L 50/90 using propulsion power supplied by specific means not covered by groups B60L50/10 - B60L50/50, e.g. by direct conversion of thermal nuclear energy into electricity
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 7/06 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/22 Dynamic electric resistor braking, combined with dynamic electric regenerative braking
• CPC Class Codes: B60L 9/00 Electric propulsion with power supply external to the vehicle electric propulsion for monorail vehicles, suspension vehicles or rack railways B60L13/00; in combination with batteries or fuel cells within the vehicle B60L50/53
• CPC Class Codes: B61C 7/04 Locomotives or motor railcars with two or more different kinds or types of engines, e.g. steam and IC engines
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 30/00 Transportation of goods or passengers via railways, e.g. energy recovery or reducing air resistance
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

The present invention is directed to a power control architecture for a vehicle, particularly a locomotive, in which a number of energy sources are connected to a common electrical bus and selectively provide energy to the bus based on the relationship between their respective output voltages and the bus voltage.

Claims

1. A motorized off road vehicle, comprising:

at least one motor;

a plurality of electrical energy converters operable to convert energy to electrical energy having a desired electrical characteristic, the plurality of electrical energy converters comprising first and second electrical energy converters having respectively first and second output voltages and first and second output currents;

a plurality of energy sources operable to provide energy to the plurality of electrical energy converters, the plurality of energy sources comprising first and second engines corresponding respectively to the first and second electrical energy converters; and

a common Direct Current (DC) power bus electrically connecting the plurality of electrical energy converters and the at least one motor and operable to transport electrical energy from the electrical energy converters to the at least one motor, wherein, at a selected time, the relationship between at least one of a current level and a voltage level of the common power bus on the one hand and at least one of the first and second output currents and the first and second output voltages of the first and second electrical energy converters on the other hand determine, at a selected point in time, which of the first and second engines supplies energy to the bus through the corresponding electrical energy converter.

2. The off road vehicle of claim 1, wherein the off road vehicle is a locomotive, wherein the at least one motor is at least one traction motor, wherein the plurality of energy sources comprise an energy storage system, wherein each of the first and second engines is one or more of a diesel engine, gas turbine engine, microturbine, Stirling engine, spark ignition engine, and fuel cell, wherein the energy storage system is one or more of a battery pack, a bank of capacitors, a compressed air storage system and a bank of flywheels, and further comprising:

at least one power control apparatus operable to control electrical energy supplied to the at least one motor, the at least one power control apparatus being positioned between the DC bus and the at least one motor.

3. The off road vehicle of claim 2, wherein the plurality of electrical energy converters include one or more of an alternator-rectifier, a rectifier, a boost circuit, a buck circuit and a buck/boost circuit, wherein the at least one power control apparatus is one or more of an inverter and a chopper circuit and wherein the at least one traction motor is a plurality of traction motors, wherein the at least one motor is a plurality of traction motors and the plurality of traction motors comprise a plurality of an AC induction motor, DC motor, permanent magnet motor and/or switched reluctance motor, wherein the first and second energy converters each comprise an alternator, and wherein the first and second output voltages are the output voltages of the corresponding alternator.

4. The off road vehicle of claim 2, wherein each of first and second electrical energy converters comprises a switch that prevents reverse energy flow from the DC bus to the corresponding engine but allows energy to flow therethrough from the corresponding engine to the DC bus, wherein the energy storage system comprises an output power control apparatus, wherein, in a first mode, an output voltage of the output power control apparatus is less than the DC bus voltage and, in a second mode, the output voltage of the output power control apparatus is at least the DC bus voltage, and wherein, in the first mode, the energy storage system receives energy from the DC bus for storage and, in the second mode, the energy storage provides energy to the DC bus from storage.

5. The off road vehicle of claim 1, wherein, in a first mode, the first output voltage is higher than the second output voltage and is at least the DC bus voltage and wherein the second output voltage is lower than the DC bus voltage, whereby the first engine but not the second engine provides energy to the DC bus through the corresponding electrical energy converter and wherein, in a second mode, the first and second output voltages are each at least the DC bus voltage, whereby both of the first and second engines provide electrical energy to the DC bus through the first and second electrical energy converters.

6. The off road vehicle of claim 5, wherein the desired electrical characteristic is at least one of a voltage and power and wherein the first and second output voltages are controlled by varying an excitation current applied to the corresponding electrical energy converter.

7. The off road vehicle of claim 5, wherein the DC bus voltage is maintained substantially constant in the first and second modes.

8. The off road vehicle of claim 5, wherein the DC bus voltage is varied in the first and second modes.

9. The off road vehicle of claim 8, wherein the DC bus voltage is allowed to vary in accordance with load power demand.

10. The off road vehicle of claim 2, wherein the DC bus voltage is allowed to vary in response to fluctuations in the output voltage of the energy storage system and/or power control apparatus.

11. The off road vehicle of claim 1, wherein each of the electrical energy converters includes an excitation circuit, the excitation circuit being operable to control the output voltage of the corresponding energy converter and thereby control when energy provided by the corresponding energy source is transported on the bus.

12. The off road vehicle of claim 9, wherein, as the at least one motor requires greater amounts of electrical energy, the bus voltage level decreases, thereby permitting at least some of the energy sources having lower output voltages to provide electrical energy to the bus.

13. The off road vehicle of claim 1, wherein at least three of the plurality of energy sources are engines, wherein each engine operates in a motoring mode in which the engine supplies energy to the bus through the corresponding electrical energy converter, an idling mode in which the engine is idling and not supplying energy to the bus through the corresponding electrical energy converter, and a down mode in which the engine is turned off, and wherein at a selected time, the first engine is in the motoring mode, the second engine is in the idling mode, and a third engine is in the down mode.

14. The off road vehicle of claim 1, wherein the power output of the first and second engines has a frequency component, and wherein, during a time when the first and second engines are operational, the frequency components are asynchronous.

15. The off road vehicle of claim 1, wherein the first engine is operating at a first revolutions per minute, wherein the second engine is operating at a second revolutions per minute, wherein the first revolutions per minute is less than the second revolutions per minute, and wherein the first and second output voltages of the first and second energy converters, corresponding respectively to the first and second engines, are approximately equal to the bus voltage.

16. The off road vehicle of claim 1, wherein the DC bus comprises first and second conductors having opposing polarities, wherein each of the plurality of electrical energy converters and the at least one motor are connected in parallel across the first and second conductors.

17. In an off road vehicle comprising at least one motor, a plurality of electrical energy converters operable to convert energy to electrical energy having a desired electrical characteristic, a plurality of energy sources operable to provide energy to the plurality of electrical energy converters, and a common Direct Current (DC) power bus electrically connecting the plurality of electrical energy converters and the at least one motor and operable to transport electrical energy from the electrical energy converters to the at least one motor, a method comprising:

at a first selected time, implementing a first set of relationships between a voltage level of the common power bus on the one hand and output voltages of the electrical energy converters on the other, whereby a first set of the energy sources provides energy to the common power bus; and

at a second selected time, implementing a second set of relationships between the voltage level of the common power bus on the one hand and output voltages of the electrical energy converters on the other, whereby a second set of energy sources provides energy to the common power bus, wherein the memberships of the first and second sets of energy sources are different.

18. The method of claim 17, wherein a first energy converter has a first output voltage and wherein the first energy converter has a second output voltage, wherein the first and second output voltages are different, and wherein, in the first set of relationships, the first output voltage is at least the common bus voltage and, in the second set of relationships, is less than the common bus voltage.

19. The method of claim 18, wherein the output voltage of the first energy converter is varied between the first and second output voltages by varying an excitation current applied to the first energy converter.

20. The method of claim 18, wherein the magnitudes of the common bus voltage at the first and second selected times are substantially the same.

21. The method of claim 17, wherein, at the first selected time, a first energy converter has a first output voltage and the power bus a first bus voltage and wherein, at the second selected time, the first energy converter has a second output voltage and the power bus a second bus voltage, wherein the first and second output voltages are substantially the same and the first and second bus voltages are different, and wherein, in the first set of relationships, the first output voltage is at least the first voltage at the first selected time and, in the second set of relationships, the second output voltage is less than the second bus voltage at the second selected tune.

22. The method of claim 21, wherein the bus voltage varies between the first and second selected times in response to load power demand.

23. The method of claim 21, wherein the bus voltage varies between the first and second selected times in response to an output voltage of an energy storage system.

24. The method of claim 17, wherein the plurality of electrical energy converters comprises first and second electrical energy converters having respectively first and second output voltages, wherein the plurality of energy sources comprises first and second engines corresponding respectively to the first and second electrical energy converters, wherein, in the first and second sets of relationships, the bus voltage on the one hand and the first and second output voltages of the first and second electrical energy converters on the other hand determine, at a selected point in time, which of the first and second engines supplies energy to the bus through the corresponding electrical energy converter.

25. The method of claim 24, wherein the off road vehicle is a locomotive, wherein the at least one motor is at least one traction motor, wherein the plurality of energy sources comprise an energy storage system, wherein each of the first and second engines is one or more of a diesel engine, gas turbine engine, microturbine, Stirling engine, spark ignition engine, and fuel cell, wherein the energy storage system is one or more of a battery pack, a bank of capacitors, a compressed air storage system and a bank of flywheels, and wherein the locomotive comprises at least one power control apparatus operable to control electrical energy supplied to the at least one motor, the at least one power control apparatus being positioned between the DC bus and the at least one motor.

26. The method of claim 25, wherein the plurality of electrical energy converters include one or more of an alternator-rectifier, a rectifier, a boost circuit, a buck circuit and a buck/boost circuit, wherein the at least one power control apparatus is one or more of an inverter and a chopper circuit and wherein the at least one traction motor is a plurality of traction motors, and wherein the at least one motor is a plurality of traction motors and the plurality of traction motors comprise a plurality of an AC induction motor, DC motor, permanent magnet motor and/or switched reluctance motor.

27. The method of claim 25, wherein each of first and second electrical energy converters comprises a switch that prevents reverse energy flow from the DC bus to the corresponding engine but allows energy to flow therethrough from the corresponding engine to the DC bus, wherein the energy storage system comprises an output power control apparatus, wherein, in a first mode, an output voltage of the output power control apparatus is less than the DC bus voltage and, in a second mode, the output voltage of the output power control apparatus is at least the DC bus voltage, and wherein, in the first mode, the energy storage system receives energy from the DC bus for storage and, in the second mode, the energy storage provides energy to the DC bus from storage.

28. The method of claim 24, wherein, in a first mode, the first output voltage is higher than the second output voltage and is at least the DC bus voltage and wherein the second output voltage is lower than the DC bus voltage, whereby the first engine but not the second engine provides energy to the DC bus through the corresponding electrical energy converter and wherein, in a second mode, the first and second output voltages are each at least the DC bus voltage, whereby both of the first and second engines provide electrical energy to the DC bus through the first and second electrical energy converters.

29. The method of claim 17, wherein at least three of the plurality of energy sources are engines, wherein each engine operates in a motoring mode in which the engine supplies energy to the bus through the corresponding electrical energy converter, an idling mode in which the engine is idling and not supplying energy to the bus through the corresponding electrical energy converter, and a down mode in which the engine is turned off, and wherein at a selected time, a first engine is in the motoring mode, a second engine is in the idling mode, and a third engine is in the down mode.

30. The method of claim 21, wherein the power output of each of the first and second engines has a frequency component, wherein, during a time when the first and second engines are operational, the frequency components are unsynchronized, wherein the power outputs for the first and second engines respectively are from the first and second energy converters, wherein the first and second energy converters each comprise a generator, and wherein the generators'"'"' speeds are asynchronous.

31. The method of claim 21, wherein the first engine is operating at a first revolutions per minute, wherein the second engine is operating at a second revolutions per minute, wherein the first revolutions per minute is less than the second revolutions per minute, and wherein the first and second output voltages of the first and second energy converters, corresponding respectively to the first and second engines, are approximately equal to the bus voltage.

32. The method of claim 21, wherein DC bus comprises first and second conductors having opposing polarities, wherein each of the plurality of electrical energy converters and the at least one motor are connected in parallel across the first and second conductors.

33. A method for operating a locomotive, the locomotive including at least one traction motor, at least one power control apparatus controlling electrical energy supplied to the at least one traction motor, a plurality of energy sources providing energy to the at least one traction motor, and at least one electrical energy converter converting the provided energy to electrical energy having a desired electrical characteristic, and a common power bus electrically connecting the at least one power control apparatus and the at least one electrical energy converter, comprising:

during a first time interval, setting a first energy converter corresponding to a first energy source to a first output voltage, the first output voltage being equal to a bus voltage;

during the first time interval, setting a second energy converter corresponding to a second energy source to a second output voltage, the second output voltage being less than the first output voltage; and

during the first time interval, the first energy source but not the second energy source providing energy to the bus for use by the at least one traction motor.

34. The method of claim 33, further comprising, during a second time interval:

increasing an excitation voltage to the second energy converter to provide a third output voltage, the third output voltage being approximately equal to the bus voltage; and

the second energy source providing energy to the bus for use by the at least one traction motor.

35. The method of claim 33, further comprising:

when a selected output voltage is less than the bus voltage, preventing electrical energy from flowing to the corresponding energy source.

36. The method of claim 33, further comprising:

an excitation circuit controlling the output voltage of a selected energy converter and thereby controlling when energy is provided by the corresponding energy source to the bus.

37. The method of claim 33, further comprising:

the bus voltage level decreasing as the at least one traction motor requires increasing amounts of electrical energy, thereby permitting at least some of the energy sources having lower output voltages to provide electrical energy to the bus.

38. The method of claim 33, wherein the plurality of energy sources comprises first, second, and third engines connected to the bus through corresponding electrical energy converters and further comprising during a second time interval:

the first engine supplying energy to the bus through the corresponding electrical energy converter;

the second engine idling and not supplying energy to the bus; and

the third engine being deactivated and not supplying energy to the bus.

39. The method of claim 33, wherein the plurality of energy sources comprise first and second engines connected to the bus through first and second electrical energy converters, wherein the power output of each of the first and second engines has a frequency component, wherein, during a time when the first and second engines are operational, the frequency components are asynchronous, wherein the power outputs for the first and second engines respectively are from the first and second energy converters, wherein the first and second energy converters each comprise a generator, and wherein the generators speeds are asynchronous.

40. The method of claim 39, further comprising:

operating the first engine at a first revolutions per minute; and

operating the second engine at a second revolutions per minute, wherein the first revolutions per minute is less than the second revolutions per minute and wherein the output voltages of first and second energy converters, corresponding respectively to the first and second engines, are approximately equal to the bus voltage.