Bi-directional power supply circuit

• US 6,700,802 B2
• Filed: 08/24/2001
• Issued: 03/02/2004
• Est. Priority Date: 02/14/2000
• Status: Expired due to Fees

• Current Assignee: Aura Systems Inc.
• Original Assignee: Aura Systems Inc.
• Inventors: Rahman, Khaliqur, Heitz, W. Stephen, Clarke, Hugh C., Ulinski, Richard J.
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US09/938,967
• Publication Number:
  US 20020041502A1
• Time in Patent Office: 921 Days
• Field of Search: 363/37, 363/127, 363/17, 363/125, 363/126, 363/36, 307/64, 307/66, 323/299
• US Class Current: 363/37
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 3/33584 Bidirectional converters
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements

Abstract

A system is described for controlling the flow of electrical power between two sources. The system includes a circuit coupled between a first source and a second source and a controller subsystem coupled to the circuit. The circuit is capable of transitioning, in a continuous manner, between a first direction wherein electrical power flows from the first source to the second source and a second direction wherein electrical power flows from the second source to the first source. The control subsystem generates control signals to selectively activate switching elements of the circuit to control the direction and the amount of electrical power flowing through the circuit between the first and second sources.

Claims

1. A system comprising:

a bi-directional circuit coupled between a first source in the form of a DC power storage source and a second source in the form of a power bus, said circuit capable of transitioning between a first direction wherein electrical power flows from the first source to the second source and a second direction wherein electrical power flows from the second source to the first source; and

a control subsystem coupled to said bi-directional circuit to generate control signals to selectively activate switching elements of said circuit to control the direction and the amount of electrical power flowing through said circuit between said first and second sources, wherein the control subsystem is capable of controlling the direction and the amount of electrical power flowing through the bi-directional circuit such that, when the bi-directional circuit transitions from one direction to the other direction, electrical power flowing in one direction between the first and second sources will drop until electrical power flow reaches zero and then electrical power will start to flow in the other direction and increase until desired electrical power flow has been reached, the control subsystem including a processor to determine pulse width and timing of control signals to be applied to the switching elements of said circuit to maintain a voltage level of the power bus within a desired range, and a signal generator coupled to said processor to generate control signals according to the pulse width and timing parameters determined by said processor, wherein said processor uses a feed forward component to estimate pulse widths of control signals to maintain the voltage level of the power bus within the desired range.

2. The system of claim 1, wherein the feed forward component is computed based at least in part on a current voltage level across battery terminals.

3. The system of claim 1, wherein said circuit comprises:

a first subcircuit coupled to a first terminal, said first subcircuit including four transistors, each of said transistors connected in parallel with a diode;

a second subcircuit to a second terminal, said second subcircuit including two transistors and an inductor; and

a transformer having a primary and a secondary winding, said primary winding coupled to said first subcircuit and said secondary winding coupled to said second subcircuit.

4. The system of claim 3, wherein said transistors of said first subcircuit are insulated gate bipolar transistors, wherein first and second insulated gate bipolar transistors of said first subcircuit are connected in series and coupled to a first terminal of said primary transformer winding and third and fourth insulated gate bipolar transistors thereof are connected in series and coupled to a second terminal of said primary transformer winding.

5. The system of claim 3, wherein said transistors of said second subcircuit are MOSFET transistors, wherein first and second MOSFET transistors of said second subcircuit are coupled to end taps of said secondary transformer winding and said inductor is coupled to a center tap of said secondary transformer winding.

6. The system of claim 3, wherein said control subsystem, responsive to a charged voltage level of a battery coupled to said second terminal and a current voltage level of a power bus coupled to said first terminal, to control the duration and timing of on and off states of said transistors of said first and second subcircuits to control the direction and amount of electrical power flowing between said first and second terminals.

16. The system of claim 1, wherein the bi-directional circuit is capable of transitioning, in a continuous manner, between the first direction and the second direction.

17. The system of claim 1, wherein said bi-directional circuit comprises:

a first subcircuit coupled to a first terminal, said first subcircuit including four transistors connected in a H-bridge configuration;

a second subcircuit to a second terminal, said second subcircuit including a first transistor, a second transistor and an inductor; and

a transformer having a primary and a secondary winding, said primary winding coupled to said first subcircuit and said secondary winding coupled to said second subcircuit,

wherein said first and second transistors of said second subcircuit are coupled to each respective end taps of said secondary transformer winding and said inductor of said second subcircuit is coupled to a center tap of said secondary transformer winding.

18. The system of claim 17, wherein the control subsystem generates (1) a first control signal (VC1) to control a first pair of diagonally opposite transistors of said first subcircuit, (2) a second control signal (VC2) to control a second pair of diagonally opposite transistors of said first subcircuit, (3) a third control signal (VC5) to control the first transistor of said second subcircuit and (4) a fourth control signal (VC6) to control the second transistor of said second subcircuit.

19. The system of claim 18, wherein the desired direction and the amount of electrical power flowing between the first and second sources is achieved by controlling the width of reverse push-pull subsection, the width of push-pull section and the width of overlap section.

20. The system of claim 19, wherein the push-pull section is defined as a time period when only one of control signals VC5 and VC6 is turned ON, the overlap section is defined as a time period when both VC5 and VC6 are turned ON and the reverse push-pull subsection is defined as a time period within the push-pull section when one of the control signals VC1 and VC2 is turned ON.

7. An apparatus comprising:

bi-directional circuit means coupled between a first source and a second source for transitioning between a first direction wherein electrical power flows from the first source to the second source and a second direction wherein electrical power flows from the second source to the first source; and

control means for controlling the direction and the amount of electrical power flowing through said circuit means between said first and second sources, wherein the control means includes processor means for determining pulse width and timing of control signals to be applied to the switching elements of said circuit to maintain the voltage level of the power bus within a desired range, and signal generator means for generating control signals according to the pulse width and timing parameters determined by said processor, and wherein said processor means computes a feed forward component based at least in part on a current voltage level across battery terminals to estimate pulse widths of control signals required to maintain the voltage level of the power bus within the desired range.

8. The apparatus of claim 7, wherein said first source is DC power storage means and said second source is power bus means.

9. The apparatus of claim 7, wherein said bi-directional circuit means comprises:

a first subcircuit coupled to a first terminal, said first subcircuit including four transistors, each of said transistors connected in parallel with a diode;

a second subcircuit to a second terminal, said second subcircuit including two transistors and an inductor; and

a transformer having a primary and a secondary winding, said primary winding coupled to said first subcircuit and said secondary winding coupled to said second subcircuit.

10. The apparatus of claim 9, wherein said control subsystem, responsive to a charged voltage level of a battery coupled to said second terminal and a current voltage level of a power bus coupled to said first terminal, to control the duration and timing of on and off states of said transistors of said first and second subcircuits to control the direction and amount of electrical power flowing between said first and second terminals.

21. The apparatus of claim 7, wherein the bi-directional circuit means is capable of transitioning, in a continuous manner, between the first direction and the second direction.

11. A bi-directional conversion unit comprising:

a bi-directional circuit coupled between a first source in the form of a DC power storage source and a second source in the form of a power bus; and

a controller to determine pulse width and timing of control signals to be applied to the switching elements of said bi-directional circuit to control the direction and the amount of electrical power flowing between the first and second sources, using a feed forward component to estimate pulse widths of the control signals required to maintain a voltage level of the power bus within a desired range.

12. The bi-directional conversion unit of claim 11, wherein said bi-directional circuit comprises:

a first subcircuit coupled to a first terminal, said first subcircuit including four transistors connected in a H-bridge configuration;

a second subcircuit to a second terminal, said second subcircuit including a first transistor, a second transistor and an inductor; and

a transformer having a primary and a secondary winding, said primary winding coupled to said first subcircuit and said secondary winding coupled to said second subcircuit,

wherein said first and second transistors of said second subcircuit are coupled to each respective end taps of said secondary transformer winding and said inductor of said second subcircuit is coupled to a center tap of said secondary transformer winding.

13. The bi-directional conversion unit of claim 12, wherein said controller generates (1) a first control signal (VC1) to control a first pair of diagonally opposite transistors of said first subcircuit, (2) a second control signal (VC2) to control a second pair of diagonally opposite transistors of said first subcircuit, (3) a third control signal (VC5) to control the first transistor of said second subcircuit and (4) a fourth control signal (VC6) to control the second transistor of said second subcircuit.

14. The bi-directional conversion unit of claim 13, wherein the desired direction and the amount of electrical power flowing between the first and second sources is achieved by controlling the width of reverse push-pull subsection, the width of push-pull section and the width of overlap section.

15. The bi-directional conversion unit of claim 14, wherein the push-pull section is defined as a time period when only one of control signals VC5 and VC6 is turned ON, the overlap section is defined as a time period when both VC5 and VC6 are turned ON and the reverse push-pull subsection is defined as a time period within the push-pull section when one of the control signals VC1 and VC2 is turned ON.