SYSTEM AND METHOD FOR VEHICLE POWER MANAGEMENT

• US 20130187590A1
• Filed: 01/20/2012
• Published: 07/25/2013
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ferrel, Mark J., DeDona, Matthew Roger, Paspal, Louis, Treharne, William David
• Granted Patent: US 9,365,115 B2
• Time in Patent Office: Days
• US Class Current: 320/104
• CPC Class Codes: B60L 1/00 Supplying electric power to auxiliary equipment of vehicles circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 53/24 Using the vehicle's propulsion converter for charging
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/1469 Regulation of the charging current or voltage otherwise than by variation of field
• 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 90/14 Plug-in electric vehicles

Abstract

A power management system for a vehicle having wheels and an electric machine operable to provide torque to drive at least one of the wheels includes a first energy storage system capable of supplying power to operate the electric machine. The system also includes a second energy storage system capable of supplying power directly to at least one vehicle load at a lower voltage than the first energy storage system. A voltage conversion device is operable to reduce a voltage of the power supplied by the first energy storage system to the lower voltage to charge the second energy storage system when the vehicle is in a key-off state.

Claims

1. A power management system for a vehicle having wheels and an electric machine operable to provide torque to drive at least one of the wheels, the power management system comprising:

a first energy storage system capable of supplying power to operate the electric machine;

a second energy storage system capable of supplying power to at least one vehicle load at a lower voltage than the first energy storage system; and

a voltage conversion device operable to reduce a voltage of the power supplied by the first energy storage system to the lower voltage to charge the second energy storage system when the vehicle is in a key-off state.

2. The power management system of claim 1, further comprising a control system including at least one controller, the control system being configured to activate the voltage conversion device to charge the second energy storage system during the key-off state when at least one predetermined event occurs.

3. The power management system of claim 2, wherein the at least one predetermined event includes the second energy storage system dropping below a predetermined state of charge.

4. The power management system of claim 2, wherein the at least one predetermined event includes the passing of a predetermined amount of time since the last time the second energy storage system was charged by the voltage conversion device during the same key-off state.

5. The power management system of claim 2, further comprising a set of electrical contactors disposed between the first energy storage system and the voltage conversion device, the control system being configured to close the electrical contactors upon occurrence of the predetermined event.

6. The power management system of claim 1, wherein the voltage conversion device is directly connected to the first energy storage system.

7. The power management system of claim 1, further comprising a voltage converterless charger configured to receive power from a source external to the vehicle and to supply power to the first energy storage system.

8. The power management system of claim 1, wherein the vehicle further includes a set of electrical contactors disposed between the first energy storage system and the electric machine, the voltage conversion device being further operable to close the electrical contactors to facilitate power transfer between the first energy storage system and the electric machine when the vehicle is in a key-on state.

9. A power management system for a vehicle having wheels and an electric machine operable to provide torque to drive at least one of the wheels, the power management system comprising:

a high voltage battery for supplying power to operate the electric machine;

a low-voltage battery for supplying power to at least one vehicle load; and

a converter operable to reduce the voltage of power received from the high voltage battery and charge the low-voltage battery when the vehicle is in a key-off state.

10. The power management system of claim 9, further comprising a controller configured to activate the converter to charge the low-voltage battery at a predetermined frequency during the key-off state.

11. The power management system of claim 9, wherein the converter is directly connected to the high voltage battery.

12. The power management system of claim 9, further comprising a voltage converterless charger configured to receive power from a source external to the vehicle and to supply power to the high voltage battery.

13. The power management system of claim 9, further comprising a controller configured to activate the converter to charge the low-voltage battery when the low-voltage battery drops below a predetermined state of charge during the key-off state.

14. The power management system of claim 9, further comprising a controller configured to activate the converter to charge the low-voltage battery when at least one predetermined event occurs during the key-off state.

15. The power management system of claim 9, wherein the vehicle further includes a set of electrical contactors disposed between the high voltage battery and the electric machine, the convertor being further operable to close the electrical contactors to facilitate power transfer between the high voltage battery and the electric machine when the vehicle is in a key-on state.

16. A method of power management for a vehicle having wheels and an electric machine operable to provide torque to drive at least one of the wheels, a high voltage battery for providing power to the electric machine, and a low-voltage battery, the method comprising:

reducing voltage of the power from the high voltage battery during a vehicle key-off state; and

charging the low-voltage battery with the reduced voltage power.

17. The method of claim 16, further comprising repeating the step of charging the low-voltage battery with the reduced voltage power at a predetermined frequency during the same key-off state.

18. The method of claim 16, wherein the step of charging the low-voltage battery with the reduced voltage power is performed when a state of charge of the low-voltage battery is below a predetermined state of charge during the key-off state.

19. The method of claim 18, further comprising monitoring the state of charge of the low-voltage battery at a predetermined frequency during the key-off state.

20. The method of claim 16, wherein the step of charging the low-voltage battery with the reduced voltage power is performed upon the occurrence of at least one predetermined event.