Circuit with a switch for charging a battery in a battery capacitor circuit

• US 7,417,407 B1
• Filed: 10/12/2005
• Issued: 08/26/2008
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: University of Toledo
• Inventors: Ashtiani, Cyrus N., Stuart, Thomas A.
• Primary Examiner(s): Nguyen; Matthew V
• Assistant Examiner(s): Zhang; Jue
• Application Number:
  US11/249,048
• Time in Patent Office: 1,049 Days
• Field of Search: 320/103, 320/141, 320/166
• US Class Current: 320/166
• CPC Class Codes: H02J 7/243 with on/off action
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A circuit for charging a battery combined with a capacitor includes a power supply adapted to be connected to the capacitor, and the battery. The circuit includes an electronic switch connected to the power supply. The electronic switch is responsive to switch between a conducting state to allow current and a non-conducting state to prevent current flow. The circuit includes a control device connected to the switch and is operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery.

Claims

1. A circuit for charging a battery combined with a capacitor, the circuit comprising:

a power supply adapted to be connected to the capacitor and the battery for charging the capacitor and the battery;

an electronic switch having a first switch terminal connected to the power supply, a second switch terminal, and a control terminal, the electronic switch being responsive to a control signal applied to the control terminal to switch between a conducting state to allow current flow between the first and second switch terminals and a non-conducting state to prevent current flow between the first and second switch terminals, wherein current flow between the first and second switch terminals charges the battery;

wherein the battery has first and second battery terminals, the capacitor has first and second capacitor terminals, and the power supply has first and second power supply terminals, and wherein the first power supply terminal is adapted to be connected to both the first capacitor terminal and the first switch terminal, and the second power supply terminal is adapted to be connected to both the second capacitor terminal and the second battery terminal;

an inductor having first and second inductor terminals, the first inductor terminal connected to the second switch terminal, the second inductor terminal adapted to be connected to the first battery terminal;

a control device connected to the switch control terminal, the control device operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery, and

a blocking diode having a cathode and an anode, the cathode connected to the second switch terminal and the anode connected to the second inductor terminal, wherein the blocking diode is controlled by voltage levels of the capacitor and the battery without using a switching circuit;

wherein the circuit is configured such that

i) after the battery has supplied a surge current, the circuit rapidly recharges the battery to its fully charged state;

ii) the battery does not experience long periods of time in a partially charged state; and

iii) when the battery is to be charged, the capacitor does not need to be discharged, thus shielding the battery from surging caused by a demand put on the circuit.

2. The circuit according to claim 1 wherein the control signal is a pulse width modulated signal with a duty cycle that varies as the battery is charged.

3. The circuit according to claim 1 further including a current sensing device connected to the control device, the current sensing device operable to measure the magnitude of a current flowing through the inductor and to supply the inductor current magnitude to the control device, the control device being responsive to the inductor current magnitude to vary the control signal duty cycle in inverse proportion to the current magnitude.

4. The circuit according to claim 3 wherein the circuit includes a free-wheeling diode having a free-wheeling cathode and a free-wheeling anode, the free-wheeling diode cathode connected to the second switch terminal and the free-wheeling diode anode connected to the second power supply terminal.

5. The circuit according to claim 4 wherein the second inductor terminal is connected to the control device to supply a battery voltage to the control device, the control device being responsive to the battery voltage to initiate a battery charging cycle.

6. The circuit according to claim 5 wherein the power supply includes a motor-generator connected to an inverter with the inverter having a first terminal that is the first power supply terminal and a second terminal that is the second power supply terminal.

7. The circuit according to claim 6 wherein the inverter is connected to the control device, the control device being operable to actuate the inverter to supply power to the electronic switch for charging the battery;

wherein the control device is configured to

i) initiate a charging cycle;

ii) generate a switch control signal to continuously switch the electronic switch between conducting and non-conducting states to charge the battery; and

iii) respond to the battery voltage to initiate a battery charging cycle.

8. The circuit according to claim 7 wherein the control device includes a microprocessor.

9. The circuit according to claim 8 wherein the electronic switch is a field-effect transistor.

10. The circuit according to claim 8 wherein the electronic switch is a bipolar transistor.

11. The circuit according to claim 8 wherein the electronic switch is an insulated gate bipolar transistor.

12. A circuit for charging a battery combined with a capacitor, wherein the battery has first and second battery terminals and the capacitor has first and second capacitor terminals, the circuit comprising:

a power supply having a first power supply terminal and a second power supply terminal, the first power supply terminal adapted to be connected to the first capacitor terminal, the second power supply terminal adapted to be connected to both the second capacitor terminal and the second battery terminal;

an electronic switch having a first switch terminal connected to the first power supply terminal and a second switch terminal, the electronic switch further having a control terminal, the electronic switch being responsive to a control signal applied to the control terminal to switch between a conducting state to allow current flow between the first and second switch terminals and a non-conducting state to prevent current flow between the first and second switch terminals;

an inductor having first and second inductor terminals, the first inductor terminal connected to the second switch terminal, the second inductor terminal adapted to be connected to the first battery terminal;

at least one blocking diode having a cathode and an anode, the cathode connected to the first power supply terminal and the anode connected to the second inductor terminal;

wherein the blocking diode is controlled by voltage levels of the capacitor and the battery without using a switching circuit, and

a control device connected to the switch control terminal, the control device operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery;

wherein the circuit is configured such that

i) after the battery has supplied a surge current, the circuit rapidly recharges the battery to its fully charged state;

ii) the battery does not experience long periods of time in a partially charged state; and

iii) when the battery is to be charged, the capacitor does not need to be discharged, thus shielding the battery from surging caused by a demand put on the circuit.

13. The circuit according to claim 12 further including a current sensing device connected to the control device, the current sensing device operable to measure the magnitude of a current flowing through the inductor and to supply the inductor current magnitude to the control device, the control device being responsive to the inductor current magnitude to vary the control signal duty cycle in inverse proportion to the current magnitude.

14. The circuit according to claim 13 wherein the circuit includes a second free-wheeling diode having a free-wheeling cathode and a free-wheeling anode, the free-wheeling diode cathode connected to the second switch terminal and the free-wheeling diode anode connected to the second power supply terminal.

15. The circuit according to claim 14 wherein the second inductor terminal is connected to the control device to supply a battery voltage to the control device, the control device being responsive to the battery voltage to initiate a battery charging cycle.

16. The circuit according to claim 15 wherein the power supply includes a motor-generator connected to an inverter with the inverter having a first terminal that is the first power supply terminal and a second terminal that is the second power supply terminal.

17. The circuit according to claim 16 wherein the inverter is connected to the control device, the control device being operable to actuate the inverter to supply power to the electronic switch for charging the battery;

wherein the control device is configured to

i) initiate a charging cycle;

ii) generate a switch control signal to continuously switch the electronic switch between conducting and non-conducting states to charge the battery; and

iii) respond to the battery voltage to initiate a battery charging cycle.

18. The circuit according to claim 17 wherein the control device includes a microprocessor.

19. The circuit according to claim 18 wherein the electronic switch is a field-effect transistor.

20. The circuit according to claim 18 wherein the electronic switch is a bipolar transistor.

21. The circuit according to claim 18 wherein the electronic switch is an insulated gate bipolar transistor.