SYSTEM AND METHOD FOR BALANCING ELECTRICAL ENERGY STORAGE DEVICES VIA DIFFERENTIAL POWER BUS AND CAPACITIVE LOAD SWITCHED-MODE POWER SUPPLY

• US 20130015820A1
• Filed: 07/12/2011
• Published: 01/17/2013
• Est. Priority Date: 07/12/2011
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Kim, Jang Dae
• Granted Patent: US 9,048,670 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits

Abstract

System and method are provided for transferring electrical energy among multiple electrical energy storage devices via a differential power bus and a capacitive load switched-mode power supply. The switched-mode power supply transfers the electrical energy between the load capacitor and the differential power bus to which the electrical energy storage devices (e.g., rechargeable batteries and/or capacitors connected in parallel or series or combinations of both) are electrically connected via bus switches. As a result, electrical energy is efficiently transferred and distributed among the electrical energy storage devices.

Claims

1. An apparatus including circuitry for transferring electrical energy among multiple electrical energy storage devices, comprising:

a first differential power bus including a first plurality of switches responsive to a first plurality of switch control signals by conveying first electrical energy from and to a first plurality of electrical energy storage devices;

a first capacitance to store and provide at least a first portion of said first electrical energy; and

a first switched-mode power supply coupled between said first differential power bus and said first capacitance and responsive to at least a first portion of one or more control signals by transferring said at least a first portion of said first electrical energy between said first differential power bus and said first capacitance.

2. The apparatus of claim 1, wherein said first switched-mode power supply is responsive to said at least a first portion of one or more control signals by transferring said at least a first portion of said first electrical energy between said first differential power bus and said first capacitance in a substantially constant current.

3. The apparatus of claim 1, further comprising a second switched-mode power supply coupled between said first differential power bus and said first capacitance and responsive to at least a second portion of said one or more control signals by transferring at least a second portion of said first electrical energy between said first differential power bus and said first capacitance.

4. The apparatus of claim 3, wherein said first and second switched-mode power supplies comprise first and second unidirectional switched-mode power supplies of mutually opposite directions.

5. The apparatus of claim 1, further comprising:

a second capacitance to store and provide at least a second portion of said first electrical energy;

a second switched-mode power supply coupled between said first differential power bus and said second capacitance and responsive to at least a second portion of said one or more control signals by transferring said at least a second portion of said first electrical energy between said first differential power bus and said second capacitance; and

at least one shared electrical energy storage device, wherein said first and second switched-mode power supplies are operably coupled via said at least one shared electrical energy storage device.

6. The apparatus of claim 5, wherein said at least one shared electrical energy storage device comprises a capacitance.

7. The apparatus of claim 1, further comprising:

a second differential power bus including a second plurality of switches responsive to a second plurality of switch control signals by conveying second electrical energy from and to a second plurality of electrical energy storage devices;

a second capacitance to store and provide at least a portion of said second electrical energy;

a second switched-mode power supply coupled between said second differential power bus and said second capacitance and responsive to at least a second portion of said one or more control signals by transferring said at least a portion of said second electrical energy between said second differential power bus and said second capacitance; and

at least one shared electrical energy storage device, wherein said first and second differential power buses are operably coupled via said at least one shared electrical energy storage device.

8. The apparatus of claim 7, wherein said at least one shared electrical energy storage device comprises a capacitance.

9. The apparatus of claim 1, wherein said first switched-mode power supply comprises an isolated switched-mode power supply.

10. The apparatus of claim 1, wherein said first switched-mode power supply comprises a bidirectional non-isolated switched-mode power supply.

11. The apparatus of claim 10, wherein said bidirectional non-isolated switched-mode power supply comprises one of a synchronous buck converter, a synchronous boost converter and a synchronous buck-boost converter.

12. The apparatus of claim 9, wherein said isolated switched-mode power supply comprises a bidirectional isolated switched-mode power supply.

13. The apparatus of claim 12, wherein said bidirectional isolated switched-mode power supply comprises one of a synchronous flyback converter, a synchronous forward converter and a synchronous push-pull converter.

14. The apparatus of claim 1, wherein at least one of said first plurality of electrical energy storage devices comprises an electrical battery.

15. The apparatus of claim 14, wherein said electrical battery comprises a rechargeable electrical battery.

16. The apparatus of claim 14, further comprising another capacitance coupled across said electrical battery.

17. The apparatus of claim 1, wherein at least one of said first plurality of electrical energy storage devices comprises another capacitance.