SYSTEM AND METHOD FOR VEHICLE POWER MANAGEMENT

• US 20160221457A1
• Filed: 04/13/2016
• Published: 08/04/2016
• 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 B., TREHARNE, William David
• Granted Patent: US 9,630,514 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 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.

2. The method of claim 1, 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.

3. The method of claim 1, 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.

4. The method of claim 3, further comprising monitoring the state of charge of the low-voltage battery at a predetermined frequency during the key-off state.

5. The method of claim 1, 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.

6. The method of claim 5, wherein the at least one predetermined event includes the passing of a predetermined amount of time since the last time the low-voltage battery was charged during the same key-off state.

7. A method of power management for a wheeled vehicle having high- and low-voltage batteries and an electric machine operable to propel the vehicle, comprising:

operating a converter 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; and

closing contactors with the converter to connect the high-voltage battery to the electric machine.

8. The method of claim 7, further comprising using the converter to reduce the voltage of power received from the high-voltage battery and charge the low-voltage battery at a predetermined frequency during the key-off state.

9. The method of claim 7, wherein operating the converter 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 is performed when a state of charge of the low-voltage battery is below a predetermined state of charge during the key-off state.

10. The method of claim 9, further comprising monitoring the state of charge of the low-voltage battery at a predetermined frequency during the key-off state.

11. The method of claim 7, wherein operating the converter 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 is performed upon occurrence of at least one predetermined event.

12. The method of claim 11, wherein the at least one predetermined event includes the passing of a predetermined amount of time since the last time the low-voltage battery was charged by the converter during the key-off state.

13. A method of power management for a wheeled vehicle having high- and low-voltage batteries and an electric machine operable to propel the vehicle, comprising:

reducing voltage of power received from the high-voltage battery with a converter when the vehicle is in a key-off state;

charging the low-voltage battery with the reduced-voltage power when the vehicle is in the key-off state; and

closing contactors with the converter to connect the high-voltage battery to the electric machine.

14. The method of claim 13, wherein reducing the voltage of power received from the high-voltage battery with the converter and charging the low-voltage battery with the reduced-voltage power when the vehicle is in a key-off state is performed upon occurrence of at least one predetermined event.

15. The method of claim 14, wherein the at least one predetermined event includes the passing of a predetermined amount of time since the last time the low-voltage battery was charged by the converter during the key-off state.

16. The method of claim 13, wherein reducing the voltage of power received from the high-voltage battery with the converter and charging the low-voltage battery with the reduced-voltage power when the vehicle is in a key-off state is performed when a state of charge of the low-voltage battery is below a predetermined state of charge during the key-off state.

17. The method of claim 16, further comprising monitoring the state of charge of the low-voltage battery at a predetermined frequency during the key-off state.

18. The method of claim 13, further comprising using the converter to reduce the voltage of power received from the high-voltage battery and charge the low-voltage battery at a predetermined frequency during the key-off state.