Electric powertrain for machine

• US 7,950,481 B2
• Filed: 09/29/2005
• Issued: 05/31/2011
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Vanderham, Michael E., Garnett, Stephen C., Zwilling, Edward L., Tonsor, Andrew J., Betz, Michael D., Casey, Kent A., Liang, Chih C.
• Primary Examiner(s): Shriver, II; J. Allen
• Assistant Examiner(s): MEYER, JACOB B
• Application Number:
  US11/237,873
• Publication Number:
  US 20070080236A1
• Time in Patent Office: 2,070 Days
• Field of Search: 180/242, 180/244, 180/248, 180/251, 180/65.1, 180/65.3, 180/65.4, 180/6.44, 180/6.2, 180/6.7, 180/9.44, 373/48, 701/41, 701/50, 475/149
• US Class Current: 180/65.31
• 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. A track-type tractor having an electric drive system comprising:

an engine configured to provide rotational energy and an electrical generator configured to receive the rotational energy from the engine and to thereby produce electrical energy;

at least one electric motor having a rotational output lying on an output axis, for receiving electrical energy from the generator and thereby producing output rotational energy at the rotational output, wherein the at least one electric motor is a liquid-cooled electric motor;

at least one power electronics unit configured to control an output of the at least one electric motor, wherein the at least one power electronics unit is liquid cooled;

a differential steering unit operably coupled to the at least one electric motor, the differential steering unit having a first output linked to a first driving member and a second output linked to a second driving member, the first and second outputs being axially aligned with one another and with a central axis of the differential steering unit, wherein the central axis of the differential steering unit is non-coaxial with the output axis of the at least one electric motor;

a hydraulic steering motor operatively coupled to the differential steering unit to cause the differential steering unit to selectively control an amount of torque supplied to each of the first and second driving members; and

an electric energy storage system configured to receive energy from the at least one electric motor during deceleration of the tractor, the storage system further being configured to provide energy to the at least one electric motor in addition to energy produced by the generator to prevent the engine from lugging or stalling.

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

3. The tractor 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.

4. The tractor of claim 1, wherein the generator is sealed and liquid cooled.

5. The tractor of claim 1, wherein the generator consists of at least one of a permanent magnet-type generator, an induction-type generator, a switched reluctance-type generator, and a hybrid combination generator.

6. The tractor of claim 1, wherein the at least one power electronics unit is housed in a sealed compartment.

7. The tractor of claim 1, including a braking system configured to reduce torque provided by at least one of the first and second driving members.

8. A track-type tractor comprising:

an engine configured to provide mechanical energy;

a generator configured to convert at least a portion of the mechanical energy provided by the engine into electric energy;

at least one electric motor operably coupled to a power electronics unit to receive the electrical energy and convert the electrical energy into rotational energy;

at least one power electronics unit configured to control an output of the at least one electric motor, wherein the power electronics unit is liquid cooled;

tracks located on each side of the tractor;

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

a hydraulic steering motor operatively coupled to the differential steering unit to cause the differential steering unit to selectively control an amount of torque supplied to each of the tracks.

9. The tractor of claim 8, further including a master controller, wherein the master controller is configured to modify the rotational speed of the generator.

10. The tractor of claim 8, wherein the hydraulic steering motor is a fluid motor operably coupled to a hydraulic system.

11. The tractor of claim 8, 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.

12. The tractor of claim 8, wherein the power electronics unit is further configured to control at least one of the engine and the generator to reduce exhaust emissions from the engine.

13. The tractor of claim 8, wherein the generator and the power electronics unit are sealed and liquid cooled.

14. The tractor of claim 8, 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.

15. The tractor of claim 8, including a braking system configured to reduce torque provided to at least one of the tracks.

16. The tractor of claim 8, further including an energy storage system configured to receive energy from the at least one electric motor during deceleration of the tractor.

17. The tractor of claim 16, wherein the energy storage system is configured to provide energy to the at least one electric motor in addition to energy produced by the generator when the tractor is traversing and actuating the work implement at the same time.

18. A track-based mobile machine comprising:

an engine configured to provide mechanical energy;

a hydraulic system powered by the engine;

a work implement powered by the hydraulic system;

a generator configured to convert at least a portion of the mechanical energy provided by the engine into electric energy;

a power electronics unit configured to receive at least a portion of the electrical energy from the generator, wherein the power electronics unit is liquid cooled;

at least one electric motor operably coupled to the power electronics unit to receive the electrical energy and convert the electrical energy into rotational energy, wherein the at least one electric motor is a sealed, liquid-cooled motor;

a track located on each side of the machine;

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

a hydraulic steering motor operatively coupled to the differential steering unit to cause the differential steering unit to selectively control an amount of torque supplied to each of the tracks; and

an electric energy storage system configured to receive energy from the at least one electric motor during deceleration of the machine and provide energy to the at least one electric motor in addition to energy produced by the generator when the work machine is traversing and actuating the work implement at the same time.

19. The machine of claim 18, further including a master controller, wherein the master controller is configured to modify the rotational speed of the generator.