Hybrid energy off highway vehicle load control system and method

• US 20050039630A1
• Filed: 08/09/2004
• Published: 02/24/2005
• Est. Priority Date: 03/27/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Young, Henry Todd, Salasoo, Lembit, Kumar, Ajith Kuttannair, King, Robert Dean
• Granted Patent: US 7,137,344 B2
• Time in Patent Office: Days
• US Class Current: 105/35
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2220/20 DC electrical machines
• CPC Class Codes: B60L 2240/70 Interactions with external data bases, e.g. traffic centres
• 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 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 7/06 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/12 for vehicles propelled by dc 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 9/02 using dc motors
• CPC Class Codes: B60L 9/16 using ac induction motors
• CPC Class Codes: B60Y 2200/14 Trucks; Load vehicles, Busses
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

A system and method for managing electrical power generated by an engine for use in connection with operating a hybrid energy off highway vehicle load control system. A load control circuit determines a current operating condition of the Off Highway Vehicle, and determines a corresponding target operating condition of the Off Highway Vehicle The load control system determines a difference between the current operating condition and a target operating condition to identify transients. The load control system delivers power from the power source to a energy storage for an initial period after a transient condition is identified and then delivers power from the power source to source to the traction motors to propel the Off Highway Vehicle. The load control system also retrieves to power from the energy storage to assist in propelling the Off Highway Vehicle.

Claims

1. A hybrid off-road vehicle having a high load to power ratio, the vehicle comprising wheels supporting the vehicle, a primary power source on the vehicle for generating primary electrical power, said power source comprising an engine and an electrical power generator, a traction motor system associated with at least one of the wheels for rotating the wheel to propel the vehicle, an electric energy storage system on the vehicle for storing and discharging electrical power, a load control circuit electrically connected to the primary power source, the energy storage system and the traction motor system for selectively delivering power from the power source to the traction motor system and from the power source to the energy storage system, a first sensor for sensing a command parameter indicative of a commanded operating condition of the vehicle, a second sensor for sensing an operating parameter indicative of a current operating condition of the vehicle, and a processor responsive to the command and operating parameters for generating a control signal provided to the load control circuit, said load control circuit selectively controlling the delivery of the power from the power source to the traction motor system and from the power source to the energy storage system as a function of the control signal.

2. The hybrid vehicle of claim 1 wherein the commanded parameter sensed by the first sensor is of a type corresponding to that of the operating parameter, and wherein the processor generates the control signal as a function of a difference between the operating and commanded parameters.

3. The vehicle of claim 1 wherein:

the command parameter specifies a commanded power output of the power source;

when the operating parameter indicates a current power output less than the commanded power output then the control signal generated by the processor causes a speed of the engine to increase in response to the command and operating parameters; and

the load control circuit directs at least a portion of the transmission of electrical power generated at the primary power source to the energy storage system for an initial period, and then directs the transmission of electrical power generated at the primary power source to the traction motor system.

4. The hybrid vehicle of claim 3 wherein the power output corresponds to a speed of the engine speed of rotation.

5. The hybrid vehicle of claim 3 wherein the initial period corresponds to a preset amount of time.

6. The hybrid vehicle of claim 3 wherein the initial period corresponds to the time required for the electrical power generated at the power source to increase to a threshold amount of power output.

7. The hybrid vehicle of claim 3 wherein the portion of generated electrical power being directed to the energy storage system during the initial period corresponds to an amount of electrical power being generated by the primary power source that exceeds the power output indicated by the sensed operating parameter.

8. The hybrid vehicle of claim 3 wherein:

when the operating parameter indicates a current power output greater than the commanded power output then the control signal generated by the processor causes a speed of the engine to be maintained at a current speed in response to the command and operating parameters; and

the load control circuit directs transmission of a portion of the electrical power generated at the primary power source to the energy storage system for the initial period.

9. The hybrid vehicle of claim 8 wherein the current speed of the engine is maintained for a predetermined time after the first sensor senses a commanded power output that corresponds to a reduction from the current power output.

10. The hybrid vehicle of claim 8 wherein the portion of generated electrical power being provided to the energy storage system corresponds to an amount of electrical energy being generated by the primary power source that exceeds the commanded power output.

11. The hybrid vehicle of claim 8 wherein the load control circuit controls a first switch for selectively interconnecting the primary power source to the storage system or to the traction motor system, wherein during the initial period the load control circuit controls the switch so that the electrical power generated at the primary power source is directed to the storage system for storage, and after the initial period the load control circuit controls the switch so that the generated electrical energy is provided to the traction motor system to propel the off highway vehicle.

12. The hybrid vehicle of claim 11 wherein the load control circuit further controls a second switch for selectively interconnecting the storage system to the traction motor system, wherein the processor is responsive to the command and operating parameters to control the load control circuit to control the second switch so that the stored electrical energy is transferred from the storage system to the traction motor system to supplement the primary electric power to propel the off highway vehicle.

13. The hybrid vehicle of claim 1 wherein the load control circuit directs the transmission of power stored in the storage system to the traction motor system to assist in propelling the vehicle when vehicle movement is initiated.

14. The hybrid vehicle of claim 1 wherein the traction motor system comprises a motoring mode for receiving electrical power to propel the vehicle and a power generation mode for generating secondary electrical power by slowing the movement of the vehicle, with the load control circuit directing the transmission of secondary electrical power generated by the traction motor system to the energy storage system for storage.

15. The hybrid vehicle in claim 14 wherein the load control circuit directs the transmission of excess electrical power being generated by the power source to the energy storage system when the current power output being generated by the power source is greater than the commanded power output, and directs the transmission of electrical power from the energy storage system to the traction motor system when the current power output is less than the commanded power output.

17. The hybrid vehicle of claim 15 wherein the difference in the current power output and the commanded power output is due to variations in a terrain over which the vehicle travels.

18. The hybrid vehicle of claim 1 further comprising at least one auxiliary electrical power usage device electrically connected to the load control circuit, with the load control circuit directing the transmission of power from the energy storage system to the auxiliary electrical power usage device when the device operates so as to maintain the electrical load on the primary power source generally constant.

19. The hybrid vehicle of claim 1 wherein the load control circuit directs the transmission of electrical power from the energy storage system to the traction motor system to propel the vehicle if the primary power source is not operating.

20. The hybrid vehicle of claim 1 wherein the load control circuit directs the transmission of electrical power from the energy storage system to the traction motor system for applying flux voltage to enable secondary power generation at the traction motor system when in the power generation mode, if the primary power source is not operating.

21. The hybrid vehicle of claim 1 further comprising resistance grids for dissipating electrical power, with the load control circuit further being electrically connected to the resistance grids and selectively directing the transmission of excess electrical power generated by the traction motor system when operating in the power generating mode.

22. The hybrid vehicle of claim 1 wherein the primary power source is a fuel cell.

23. The hybrid vehicle of claim 1 wherein the energy storage system comprises a fuel cell.

24. The hybrid vehicle of claim 1 wherein the off highway vehicle is a dump vehicle or a locomotive.

16. The hybrid vehicle of clam 15 wherein the difference in the current power output and the commanded power output is due to relatively rapid changes of throttle positions.

25. A method for managing electrical power generated by a power source for use in connection with operating a hybrid energy off highway vehicle, wherein the vehicle includes wheels supporting the vehicle, the primary power source on the vehicle for generating primary electrical power, said power source including an engine and an electrical power generator, a traction motor system associated with at least one of the wheels for rotating the wheel to propel the vehicle, said method comprising:

sensing an operating parameter of the off highway vehicle, said operating parameter being indicative of a current operating condition;

sensing a commanded parameter for the off highway vehicle, said commanded parameter being indicative of a commanded operating condition;

calculating a difference between the current operating condition and the commanded operating condition; and

selectively controlling the delivery of the power from the power source to the traction motor system and from the power source to an energy storage system as function of the calculated difference for the controlling the generation, transmission and storage of power on the vehicle.

26. The method of claim 25 wherein sensing a current operating condition includes sensing a current power output being generated by the power source, and wherein sensing the commanded operating condition includes sensing a commanded power output

27. The method of claim 26 wherein the power output corresponds to a speed of the engine in revolutions per minute (rpm), and further including increasing a speed of the engine and power generation in response to the command and operating parameters when the sensed current power output is less than the sensed commanded power output, and wherein selectively controlling the delivery of the power from the power source includes directing at least a portion of the transmission of electrical power generated at the primary power source to the energy storage system for an initial period, and then directing the transmission of electrical power generated at the primary power source to the traction motor system.

28. The method of claim 27 wherein the initial period corresponds to a preset amount of time.

29. The method of claim 27 wherein the initial period corresponds to the time required for the electrical power generated at the power source to increase to a threshold amount of power output.

30. The method of claim 27 wherein the portion of generated electrical power being directed to the energy storage system during the initial period corresponds to an amount of electrical power being generated by the primary power source that exceeds the current power output.

31. The method of claim 27 further including maintaining a current speed of the engine and power generation in response to the command and operating parameters when the sensed current power output is greater than the sensed commanded power output, and wherein selectively controlling the delivery of the power from the power source includes directing at least a portion of the transmission of electrical power generated at the primary power source to the energy storage system for the initial period, and then directing the transmission of electrical power generated at the primary power source to the traction motor system.

32. The method of claim 31 wherein the portion of generated electrical power being provided to the energy storage system corresponds to an amount of electrical energy being generated by the primary power source that exceeds the commanded power output.

33. The method of claim 25 further including directing the transmission of electrical power from the energy storage system to the traction motor system to propel the vehicle if the primary power source is not operating.

34. The method of claim 25 wherein the traction motor system comprises a motoring mode for receiving electrical power to propel the vehicle and a power generation mode for generating secondary electrical power by slowing the movement of the vehicle, and wherein the method further includes directing the transmission of electrical power from the energy storage system to the traction motor system for applying flux voltage to enable secondary power generation at the traction motor system when in the power generation mode, if the primary power source is not operating.