Bi-directional dc to dc converter for energy storage applications

• US 6,243,277 B1
• Filed: 05/05/2000
• Issued: 06/05/2001
• Est. Priority Date: 05/05/2000
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Jenkins, Daniel E., Peterson, Brent C., Sun, Jian
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/565,390
• Time in Patent Office: 396 Days
• Field of Search: 363/16, 363/65, 323/222, 323/224, 323/282, 323/283, 323/284, 323/285
• US Class Current: 363/65
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 3/33584 Bidirectional converters
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A bi-directional energy storage module and method of operation is disclosed. The converter includes an inductive component, an energy storage element, two diodes and two switches. One switch is positioned in a first sub-circuit between an input voltage source and the inductive component and the other switch is positioned in a second sub-circuit between the inductive component and the energy storage element. The inductive component can be an inductor or a transformer. The energy storage element can be a battery or a capacitor. A hysteretic control structure can be used to activate and control the charging and discharging modes of operation. Voltage across the energy storage element and current through the inductive component are monitored. The switches are controlled to keep the monitored parameters within established bounds. Inrush current problems are eliminated and simple gate drive mechanisms are facilitated. The invention can be used in battery charging and discharging applications. The invention can also be used in an energy storage module of a system providing an uninterrupted power supply.

Claims

1. An energy storage module, comprising:

a bi-directional circuit, comprising;

a first sub-circuit, comprising;

a power source connector structure, comprising a power connector first lead and a power connector second lead, to connect said first sub-circuit to an electrical power supply, said power connector first lead to receive electrical energy having a polarity opposite that to be received by said power connector second lead;

an inductive component, comprising an inductive component first connector and an inductive component second connector, said inductive component first connector coupled with said power connector first lead;

a first switch, capable of bi-directional current flow, comprising a first switch first lead and a first switch second lead, said first switch first lead coupled with said power connector second lead, said first switch second lead coupled with said inductive component second connector, said first switch being switchable between a non-conducting state, wherein current cannot flow in said first sub-circuit from said power source connector structure to said inductive component, and a conducting state, wherein current can flow from said power source connector structure to said inductive component; and

a first diode, coupled in parallel with said first switch, comprising a first diode anode and a first diode cathode, said first diode oriented to prevent flow of current from said power source connector structure to said inductive component when said first switch is in said non-conducting state; and

a second sub-circuit, comprising;

an energy storage element, comprising a storage element first lead and a storage element second lead, said storage element first lead having a polarity opposite that of energy to be received by said power connector first lead, said storage element second lead having a polarity opposite that of energy to be received by said power connector second lead, said storage element first lead coupled with said inductive component first connector, said storage element second lead coupled with said inductive component second connector;

a second diode, comprising a second diode anode and a second diode cathode, said second diode oriented on said second sub-circuit so as to permit charging of said energy storage element with current transferred from said inductive component and to prevent passage through said second diode of current discharged from said energy storage element; and

a second switch, capable of bi-directional current flow, coupled in parallel with said second diode, comprising a second switch first lead coupled with said second diode cathode and a second switch second lead coupled with said second diode anode, said second switch having a non-conducting state wherein current cannot flow in said second sub-circuit from said energy storage element to said inductive component, and a conducting state wherein current can flow from said energy storage element to said inductive component; and

a variable frequency control component, controlling said first switch to direct current from said power source connector structure to said inductive component in a charging mode and controlling said second switch to direct current from said energy storage element to said inductive component in a discharging mode of operation, said variable frequency control component controlling said bi-directional circuit such that current does not flow between said power source connector structure and said inductive component when current is flowing about said second sub-circuit.

2. The energy storage module of claim 1, wherein said inductive component comprises an inductor.

3. The energy storage module of claim 1, wherein said inductive component comprises a transformer, said transformer comprising a first winding and a second winding, said first winding comprising a first winding first lead and a first winding second lead, said second winding comprising a second winding first lead and a second winding second lead, said inductive component first connector comprising said first winding first lead and said second winding first lead, said inductive component second connector comprising said first winding second lead and said second winding second lead, wherein said inductive component is coupled with said power connector first lead via said first winding first lead, wherein said inductive component is coupled with said first switch second lead via said first winding second lead, wherein said inductive component is coupled with said storage element first lead via said second winding first lead, and wherein said inductive component is coupled with said storage element second lead via said second winding second lead.

4. The energy storage module of claim 1, wherein said variable frequency control component includes functionality to operate said second switch in a closed manner such that it performs a rectification process.

5. The energy storage module of claim 1, wherein said energy storage element comprises a capacitor.

6. The energy storage module of claim 1, further comprising an input voltage source coupled with said power source connector structure.

7. The energy storage module of claim 1, wherein said power connector first lead is to transfer energy having a positive polarity and said power connector second lead is to transfer energy having a negative polarity, and wherein said first diode anode is directly coupled with said power connector second lead and said first diode cathode is coupled with said power connector first lead via said inductive component.

8. The energy storage module of claim 1, wherein said power connector first lead is to transfer energy having a negative polarity and said power connector second lead is to transfer energy having a positive polarity, and wherein said first diode cathode is directly coupled with said power connector second lead and said first diode anode is coupled with said power connector first lead via said inductive component.

9. The energy storage module of claim 7, wherein said second diode anode is directly coupled with said storage element first lead, and wherein said second diode cathode is coupled with said storage element second lead via said inductive component.

10. The energy storage module of claim 7, wherein said second diode cathode is directly coupled with said storage element second lead, and wherein said second diode anode is coupled with said storage element first lead via said inductive component.

11. The energy storage module of claim 8, wherein said second diode cathode is directly coupled with said storage element first lead, and wherein said second diode anode is coupled with said storage element second lead via said inductive component.

12. The energy storage module of claim 8, wherein said second diode anode is directly coupled with said storage element second lead, and wherein said second diode cathode is coupled with said storage element first lead via said inductive component.

13. The energy storage module of claim 3, wherein said power connector first lead is to transfer energy having a positive polarity and said power connector second lead is to transfer energy having a negative polarity, wherein said first diode anode is directly coupled with said power connector second lead and said first diode cathode is coupled with said power connector first lead via said inductive component;

and wherein said second diode cathode is directly coupled with said storage element second lead, said second diode anode is coupled with said storage element first lead via said inductive component, and said second switch second lead is conductively coupled with said power connector second lead; and

further comprising a common point of reference, located between said power connector second lead and said second switch second lead.

14. The energy storage module of claim 10, further comprising a common point of reference, located between said power connector second lead and said first switch first lead;

and further comprising a half-bridge driver coupled with said second switch.

15. The energy storage module of claim 1, wherein said first switch and said first diode are contained in a single electrical component.

16. The energy storage module of claim 15, wherein said single electrical component is a MOSFET.

17. The energy storage module of claim 15, wherein said second switch and said second diode are contained in an additional single electrical component.

18. The energy storage module of claim 17, wherein said additional single electrical component is a MOSFET.

19. The energy storage module of claim 17, wherein said single electrical component is a P-channel MOSFET and wherein said additional single electrical component is an N-channel MOSFET.

20. The energy storage module of claim 4, wherein said variable frequency control component further includes functionality to operate said first switch in a closed manner such that it performs a rectification process.

21. A method of operating a bi-directional energy storage module, comprising the steps of:

directing electrical current from a voltage source to an inductive component;

monitoring current passing through said inductive component;

ceasing to direct electrical current through said inductive component upon determining that current passing through said inductive component has reached a specified maximum level;

conducting, after said ceasing to direct step, electrical current exiting said inductive component to an energy storage element;

monitoring voltage level across said energy storage element;

re-directing electrical current from said voltage source to said inductive component upon determining that current passing through said inductive component has fallen to a specified minimum level; and

suspending transfer of current to said energy storage element upon determining that voltage across said energy storage element has reached a specified maximum voltage level.

22. The method of claim 21, further comprising the step of re-initiating transfer of current to said energy storage element upon determining that voltage across said energy storage element has fallen to a specified minimum voltage level.

23. The method of claim 21, further comprising the step of signaling a charging mode of operation.

24. The method of claim 21, wherein said monitoring current step comprises comparing sensed current through said inductive component with a reference value.

25. The method of claim 21, wherein said conducting step comprises closing a switch located in a sub-circuit containing said inductive component and said energy storage element.

26. The method of claim 21, further comprising the step of signaling a discharging mode of operation upon determining that voltage across said voltage source has fallen to a minimum voltage source voltage level.

27. The method of claim 26, further comprising the steps of:

discharging electrical current from said energy storage element to said inductive component;

ceasing to discharge electrical current from said energy storage element to said inductive component upon determining that current passing through said inductive component has reached a specified maximum level;

transferring, after said ceasing to discharge step, electrical current exiting said inductive component to said voltage source;

re-discharging electrical current from said energy storage element to said inductive component upon determining that current passing through said inductive component has fallen to a specified minimum level;

suspending discharge of current to said voltage source upon determining that voltage across said voltage source has reached a specified maximum voltage level; and

re-initiating discharge of current to said voltage source upon determining that voltage across said voltage source has fallen to a specified minimum voltage level.

28. An energy storage module, comprising:

bi-directional circuit means for permitting charging and discharging operation of the energy storage module, comprising;

inductive component means for receiving and transferring electrical energy;

storage element means for storing electrical energy;

first bi-directional sub-circuit means for transferring electrical energy between an input power source and said inductive component means; and

second bi-directional sub-circuit means for transferring electrical energy between said storage element means and said inductive component means; and

variable frequency control means for controlling discharging mode and charging mode operation of said bi-directional circuit means such that current cannot flow through said first bi-directional sub-circuit means when current is flowing through said second bi-directional sub-circuit means.