Electric powertrain for work machine

• US 20070080236A1
• Filed: 09/29/2005
• Published: 04/12/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Betz, Michael, Garnett, Stephen, Tonsor, Andrew, Casey, Kent, Liang, Chih, Zwilling, Edward, Vanderham, Michael
• Granted Patent: US 7,950,481 B2
• Time in Patent Office: Days
• US Class Current: 237/12.100
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60Y 2200/25 Track vehicles
• CPC Class Codes: B60Y 2200/411 Bulldozers, Graders
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An electric powertrain includes an engine configured to provide mechanical energy and a generator operably coupled to the engine and configured to convert at least a portion of the mechanical energy into electric energy. The electric powertrain further includes at least one electric motor operably coupled to the generator, a plurality of driving members, and at least one power electronics unit configured to control at least one of the engine and the generator. The at least one electric motor is configured to provide torque for the plurality of driving members.

Claims

1. An electric powertrain comprising:

an engine configured to provide mechanical energy;

a generator operably coupled to the engine and configured to convert at least a portion of the mechanical energy into electric energy;

at least one electric motor operably coupled to the generator;

a plurality of driving members; and

at least one power electronics unit configured to control at least one of the engine and the generator,

wherein the at least one electric motor is configured to provide torque for the plurality of driving members.

2. The electric powertrain of claim 1, wherein the at least one electric motor includes a sealed, brushless, liquid-cooled electric motor.

3. The electric powertrain of claim 1, wherein the at least one electric motor includes two electric motors, wherein the two electric motors are operably coupled to the plurality of driving members such that torque is supplied to one of the plurality of driving members via one of the two electric motors, and torque is supplied to another of the plurality of driving members via another of the two electric motors.

4. The electric powertrain of claim 3, including at least one power electronics unit configured to control an output of at least one of the two electric motors.

5. The electric powertrain of claim 1, including a differential steering unit operably coupled to the at least one electric motor, the differential steering unit being configured to selectively control the amount of torque supplied to each of the plurality of driving members.

6. The electric powertrain of claim 5, wherein the differential steering unit is operably coupled to the at least one electric motor via a mechanical link.

7. The electric powertrain of claim 5, including a steering motor operably coupled to the differential steering unit, the steering motor being configured to selectively control the amount of torque supplied to each of the plurality of driving members.

8. The electric powertrain of claim 1, wherein the at least one electric motor includes at least one of a permanent magnet-type motor, an induction-type motor, a switched reluctance-type motor, and a hybrid combination electric motor.

9. The electric powertrain of claim 1, wherein the generator and the at least one power electronics unit are sealed and liquid cooled.

10. The electric powertrain of claim 1, wherein the generator includes at least one of a permanent magnet-type generator, an induction-type generator, a switched reluctance-type generator, and a hybrid combination generator.

11. The electric powertrain of claim 1, including at least one power electronics unit configured to control an output of the at least one electric motor.

12. The electric powertrain of claim 1, including a braking system configured to reduce energy provided by at least one of the plurality of driving members.

13. The electric powertrain of claim 12, wherein the braking system includes a regenerative braking system configured to convert kinetic energy associated with at least one of the plurality of driving members to electric energy for at least one of storage and use in the electric powertrain.

14. The electric powertrain of claim 1, wherein the at least one electric motor includes at least three electric motors.

15. The electric powertrain of claim 1, including a planetary gear unit.

16. The electric powertrain of claim 15, wherein the at least one electric motor includes at least three electric motors, each of the at least three electric motors being configured to provide input to the planetary gear unit.

17. A work machine comprising:

an engine configured to provide the work machine with mechanical energy;

a generator operably coupled to the engine and configured to convert at least a portion of the mechanical energy into electric energy;

at least one electric motor operably coupled to the generator, the at least one electric motor having a high power density;

driving members located on either side of the work machine;

a differential steering unit operably coupled to the at least one electric motor and the driving members, the differential steering unit being configured to selectively control an amount of torque supplied to each of the driving members; and

ground engaging members configured to propel the work machine, the ground engaging members being operably coupled to the driving members,

wherein the at least one electric motor is configured to provide torque for the driving members such that the ground engaging members propel the work machine.

18. The work machine of claim 17, including at least one work implement.

19. The work machine of claim 17, wherein the driving members include a plurality of track driving members, and the ground engaging members include a plurality of ground engaging tracks.

20. The work machine of claim 17, wherein the at least one electric motor includes a sealed, brushless, liquid-cooled electric motor.

21. The work machine of claim 17, wherein the differential steering unit is operably coupled to the at least one electric motor via a mechanical link.

22. The work machine of claim 17, including a steering motor operably coupled to the differential steering unit, the steering motor being configured to selectively control the amount of torque supplied to each of the driving members.

23. The work machine of claim 17, wherein the at least one electric motor includes at least one of a permanent magnet-type motor, an induction-type motor, and a switched reluctance-type electric motor.

24. The work machine of claim 17, including a power electronics unit configured to control at least one of the engine and the generator to reduce exhaust emissions from the engine.

25. The work machine of claim 24, wherein the generator and the power electronics unit are sealed and liquid cooled.

26. The work machine of claim 17, wherein the generator includes at least one of a permanent magnet-type generator, an induction-type generator, a switched reluctance-type generator, and a hybrid combination generator.

27. The work machine of claim 17, including at least one power electronics unit configured to control an output of the at least one electric motor.

28. The work machine of claim 17, including a braking system configured to reduce torque provided to at least one of the driving members.

29. The work machine of claim 28, wherein the braking system includes a regenerative braking system configured to convert kinetic energy associated with at least one of the driving members to electric energy for at least one of storage and use in the work machine.

30. The work machine of claim 17, wherein the at least one electric motor includes at least three electric motors, each of the at least three electric motors being configured to provide input to the differential steering unit.

31. A work machine comprising:

at least one work implement;

an engine configured to provide the work machine with mechanical energy;

a generator operably coupled to the engine and configured to convert at least a portion of the mechanical energy into electric energy;

at least two electric motors operably coupled to the generator,

at least two driving members located on either side of the work machine; and

ground engaging members configured to propel the work machine, the ground engaging members being operably coupled to the driving members,

wherein the at least two electric motors are operably coupled to the at least two driving members such that torque is supplied to one of the at least two ground engaging members via one of the at least two electric motors, and torque is supplied to another of the at least two ground engaging members via another of the at least two electric motors.

32. The work machine of claim 31, including at least one power electronics unit configured to control an output of at least one of the at least two electric motors.

33. A work machine comprising:

at least one work implement;

an engine configured to provide the work machine with mechanical energy;

a generator operably coupled to the engine and configured to convert at least a portion of the mechanical energy into electric energy;

at least one electric motor operably coupled to the generator, the at least one electric motor being a sealed, brushless, liquid-cooled electric motor;

driving members located on either side of the work machine; and

ground engaging members configured to propel the work machine, the ground engaging members being operably coupled to the driving members,

wherein the at least one electric motor is configured to provide torque for the driving members such that the ground engaging members propel the work machine.

34. The work machine of claim 33, wherein the driving members include a pair track driving members, and the ground engaging members include a pair of ground engaging tracks.

35. The work machine of claim 33, wherein the at least one electric motor includes two electric motors, wherein the two electric motors are operably coupled to the driving members such that torque is supplied to one of the ground engaging members via one of the two electric motors, and torque is supplied to another of the ground engaging members via another of the two electric motors.

36. The work machine of claim 35, including at least one power electronics unit configured to control an output of at least one of the two electric motors.

37. The work machine of claim 33, including a differential steering unit operably coupled to the at least one electric motor, the differential steering unit being configured to selectively control an amount of torque supplied to each of the ground engaging members.

38. The work machine of claim 37, wherein the differential steering unit is operably coupled to the at least one electric motor via a mechanical link.

39. The work machine of claim 37, including a steering motor operably coupled to the differential steering unit, the steering motor being configured to selectively control the amount of torque supplied to each of the driving members.

40. The work machine of claim 33, wherein the at least one electric motor includes at least one of a permanent magnet-type motor, an induction-type motor, and a switched reluctance-type electric motor.

41. The work machine of claim 33, including a power electronics unit configured to control at least one of the engine and the generator to reduce exhaust emissions from the engine.

42. The work machine of claim 41, wherein the generator and the power electronics unit are sealed and liquid cooled.

43. The work machine of claim 33, wherein the generator includes at least one of a permanent magnet-type generator, an induction-type generator, a switched reluctance-type generator, and a hybrid combination generator.

44. The work machine of claim 33, including at least one power electronics unit configured to control an output of the at least one electric motor.

45. The work machine of claim 33, including a braking system configured to reduce torque provided to at least one of the driving members.

46. The work machine of claim 45, wherein the braking system includes a regenerative braking system configured to convert kinetic energy associated with at least one of the driving members to electric energy for at least one of storage and use in the work machine.

47. The work machine of claim 33, including a differential steering unit, wherein the at least one electric motor includes at least three electric motors, each of the at least three electric motors being configured to provide input to the differential steering unit.

48. A method for operating a work machine including ground engaging members and at least one work implement, the method comprising:

operating an engine configured to provide the work machine with mechanical energy;

converting at least a portion of the mechanical energy into electric energy via a generator operably coupled to the engine;

propelling the work machine by driving the ground engaging members via torque supplied by at least one electric motor operably coupled to the generator; and

controlling at least one of the engine and the generator by operably coupling at least one power electronics unit to the engine and the generator and controlling at least one of the engine and the generator via the at least one power electronics unit.

49. The method of claim 48, wherein controlling at least one of the engine and the generator includes controlling a speed of the engine such that the speed is held within a speed range configured to reduce exhaust emissions.

50. The method of claim 48, wherein controlling at least one of the engine and the generator includes controlling a load of the generator such that the exhaust emissions of the engine are reduced.

51. The method of claim 48, including

operating the engine within an engine speed range;

and

operating the generator within a generator load range,

wherein engine speed range and the generator load range are selected to reduce the exhaust emissions of the engine.

52. The method of claim 48, including selecting a speed range of the generator to increase efficiency of the conversion of mechanical energy into electric energy.