Dc-dc converters providing reduced deadtime

• US 20050078491A1
• Filed: 12/27/2002
• Published: 04/14/2005
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: Song, Wei, Zhu, Yan
• Granted Patent: US 6,995,987 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 1/385 with means for correcting output voltage deviations introduced by the dead time
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/3353 having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
• CPC Class Codes: H02M 3/33569 having several active switching elements H02M3/3353 takes precedence
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/337 in push-pull configuration H02M3/33576 takes precedence; with self-oscillating arrangements H02M3/3382, H02M3/3385
• CPC Class Codes: H02M 3/3372 of the parallel type
• CPC Class Codes: H02M 3/3374 with preregulator, e.g. current injected push-pull

Abstract

A DC-DC power converter (100) that provides increased power density, reduced size, and reduced costs of manufacture. The DC-DC power converter (100) includes first and second input terminals (101, 102), a plurality of output terminals (116, 117), and at least one electrical element (108/109) connected to at least one of the first and second input terminals (101, 102). In the event a first voltage is applied across the first and second input terminals (101, 102), the electrical element (108/109) provides a second voltage having a value between the first voltage value and a reference voltage value. The DC-DC power converter (100) further includes a transformer (110) having a primary winding (111) and a secondary winding (112), and a switch assembly (103-107) operatively connected to the first input terminal (101), the second input terminal (102), the electrical element (108/109), and the transformer primary winding (111). In the event the first voltage is applied across the first and second input terminals (101, 102), the switch assembly (103-107) switchably applies the first, second, and reference voltages across the transformer primary winding (111) to generate at least one third voltage across the transformer secondary winding (112). The DC-DC power converter (100) further includes a rectifier (113) connected between the transformer secondary winding (112) and the output terminals (116, 117).

Claims

1. A DC-DC power converter, comprising:

first and second input terminals;

at least one electrical element connected to at least one of the first and second input terminals, the at least one electrical element being operative, in the event a first voltage is applied across the first and second input terminals, to provide a second voltage having a value between the first voltage value and a reference voltage value;

at least one transformer having at least one primary winding and at least one secondary winding;

a switch assembly including a plurality of switching elements, the switch assembly being operatively connected to the first input terminal, the second input terminal, the electrical element, and the transformer primary winding, wherein the switch assembly is operative, in the event the first voltage is applied across the first and second input terminals, to switchably apply the first voltage, the second voltage, and the reference voltage, across the transformer primary winding to generate at least one third voltage across the transformer secondary winding;

a plurality of output terminals; and

a rectifier connected between the transformer secondary winding and the output terminals.

2. The DC-DC power converter of claim 1 further including a filter connected between the rectifier and the output terminals.

3. The DC-DC power converter of claim 1 wherein the electrical element is selected from the group consisting of a capacitor, a battery, a solar cell, and a second DC-DC power converter.

4. The DC-DC power converter of claim 1 wherein the switch assembly comprises:

first and second switching elements each having a first connection and a second connection, wherein the first connection of the first switching element is connected to the first input terminal, the second connection of the first switching element is connected to the first connection of the second switching element, and the second connection of the second switching element is connected to the second input terminal;

third and fourth switching elements each having a first connection and a second connection, wherein the first connection of the third switching element is connected to the first input terminal, the second connection of the third switching element is connected to the first connection of the fourth switching element, and the second connection of the fourth switching element is connected to the second input terminal; and

wherein a first connection of the transformer primary winding is connected to the second connection of the first switching element, and a second connection of the transformer primary winding is connected to the second connection of the third switching element.

5. The DC-DC power converter of claim 4 wherein the switch assembly further includes a fifth switching element having a first connection and a second connection, wherein the first connection of the fifth switching element is connected to a first connection of the at least one electrical element, and the second connection of the fifth switching element is connected to the first connection of the transformer primary winding.

6. The DC-DC power converter of claim 1 wherein the at least one electrical element includes first and second electrical elements each having a first connection and a second connection, wherein the first connection of the first electrical element is connected to the first input terminal, the second connection of the first electrical element is connected to the first connection of the second electrical element, and the second connection of the second electrical element is connected to the second input terminal.

7. The DC-DC power converter of claim 6 wherein the first and second electrical elements comprise respective capacitors.

8. The DC-DC power converter of claim 5 wherein the fifth switching element includes a plurality of switching sub-elements.

9. The DC-DC power converter of claim 1 further including at least one inductor, the inductor and the transformer primary winding being serially connected, and wherein the switch assembly is operative, in the event the first voltage is applied across the first and second input terminals, to switchably apply the first voltage, the second voltage, and the reference voltage across the inductor and the transformer primary winding.

10. The DC-DC power converter of claim 9 wherein at least one of the plurality of switching elements is operative to provide the Zero Voltage Switching (ZVS) property.

11. The DC-DC power converter of claim 1 wherein the transformer includes first and second primary windings each having a first connection and a second connection, and the switch assembly comprises:

first and second switching elements, the first switching element and the first transformer primary winding being connected across the first and second input terminals and forming a first node, and the second switching element and the second transformer primary winding being connected across the first and second input terminals and forming a second node; and

third and fourth switching elements, the third switching element being connected across a first connection of the electrical element and the first node, and the fourth switching element being connected across the first connection of the electrical element and the second node.

12. The DC-DC power converter of claim 11 further including a filter connected between the rectifier and the output terminals.

13. The DC-DC power converter of claim 11 wherein each of the third and fourth switching elements comprise a respective plurality of switching sub-elements.

14. The DC-DC power converter of claim 11 wherein the transformer includes first and second secondary windings.

15. The DC-DC power converter of claim 1 further comprising a first transformer and a second transformer each including a primary winding and a secondary winding, each of the primary and secondary windings having a first connection and a second connection, and the switch assembly comprises:

first and second switching elements, the first switching element and the primary winding of the first transformer being connected across the first and second input terminals and forming a first node, and the second switching element and the primary winding of the second transformer being connected across the first and second input terminals and forming a second node; and

third and fourth switching elements, the third switching element being connected across a first connection of the electrical element and the first node, and the fourth switching element being connected across the first connection of the electrical element and the second node.

16. The DC-DC power converter of claim 15 further including a filter connected between the rectifier and the output terminals.

17. A method of operating a DC-DC power converter, comprising the steps of:

in the event a first voltage is applied across first and second input terminals of the DC-DC power converter, providing a second voltage having a value between the first voltage value and a reference voltage value by at least one electrical element connected to at least one of the first and second input terminals;

switchably applying the first voltage, the second voltage, and the reference voltage across a primary winding of a transformer by a switch assembly, thereby generating at least one third voltage across a secondary winding of the transformer, the switch assembly being operatively connected to the first input terminal, the second input terminal, the electrical element, and the transformer primary winding; and

providing the at least one third voltage to a rectifier by the transformer secondary winding, thereby generating a fourth rectified voltage at output terminals of the DC-DC power converter.

18. The method of claim 17 further including the step of providing the fourth rectified voltage to a filter by the rectifier, the filter being disposed between the rectifier and the output terminals.

19. The method of claim 17 wherein the first providing step includes providing the second voltage by the at least one electrical element, the electrical element being selected from the group consisting of a capacitor, a battery, and a second DC-DC power converter.

20. The method of claim 17 wherein the applying step includes switchably applying at least the first voltage and the second voltage across the transformer primary winding by the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being less than or equal to two times the first voltage minimum value, and wherein the switch assembly includes a plurality of switching elements, the respective switching elements operating according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with no deadtime.

21. The method of claim 17 wherein the applying step includes switchably applying the first voltage, the second voltage, and the reference voltage across the transformer primary winding by the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being greater than two times the first voltage minimum value, and wherein the switch assembly includes a plurality of switching elements, the respective switching elements operating according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with a predetermined amount of deadtime.

22. The method of claim 17 wherein the applying step includes switchably applying the first voltage, the second voltage, and the reference voltage across the transformer primary winding and at least one inductor, the transformer primary winding and the at least one inductor being serially connected.

23. The method of claim 22 wherein the applying step includes switchably applying the first voltage, the second voltage, and the reference voltage across the transformer primary winding and the at least one inductor, the first voltage, the second voltage, and the reference voltage being switchably applied while satisfying the Zero Voltage Switching (ZVS) property in at least one of a plurality of switching elements included in the switch assembly.

24. A DC-DC power converter, comprising:

a switch assembly including

first and second input terminals,

at least one electrical element connected to at least one of the first and second input terminals, the at least one electrical element being operative, in the event a first voltage is applied across the first and second input terminals, to provide a second voltage having a value between the first voltage value and a reference voltage value,

first and second output terminals, and

a switch subassembly including a plurality of switching elements, the switch subassembly being operatively connected to the first input terminal, the second input terminal, and the electrical element, wherein the switch subassembly is operative, in the event the first voltage is applied across the first and second input terminals, to switchably apply the first voltage, the second voltage, and the reference voltage across the first and second output terminals; and

a second DC-DC power converter operatively connected to the first and second output terminals of the switch assembly, the second DC-DC power converter being configured to receive the first voltage, the second voltage, and the reference voltage applied across the first and second output terminals, and to generate at least one third voltage.

25. The DC-DC power converter of claim 24 wherein the electrical element is selected from the group consisting of a capacitor, a battery, a solar cell, and a third DC-DC power converter.

26. The DC-DC power converter of claim 24 wherein the switch assembly comprises:

first and second switching elements each having a first connection and a second connection, the first connection of the first switching element being connected to the second connection of the second switching element to form a first node, and the first node being connected to a first connection of the electrical element;

third and fourth switching elements, the third switching element being connected between the first input terminal and the second connection of the first switching element, and the fourth switching element being connected between the second input terminal and the first connection of the second switching element; and

wherein the second connection of the first switching element and the first connection of the second switching element are connected to the first and second output terminals, respectively.

27. The DC-DC power converter of claim 26 wherein the first and second switching elements comprise respective diodes.

28. The DC-DC power converter of claim 26 wherein the at least one electrical element includes first and second electrical elements, the first and second electrical elements being serially connected to form the first connection of the at least one electrical element.

29. The DC-DC power converter of claim 28 wherein the first and second electrical elements comprise respective capacitors.

30. The DC-DC power converter of claim 24 wherein the second DC-DC power converter comprises an isolated DC-DC power converter.

31. The DC-DC power converter of claim 30 wherein the isolated DC-DC power converter comprises a dual-ended power converter.

32. The DC-DC power converter of claim 31 wherein the dual-ended power converter is selected from the group consisting of a full-bridge converter, a half-bridge converter, and a push-pull converter.

33. The DC-DC power converter of claim 30 wherein the isolated DC-DC power converter comprises a dual-forward converter.

34. The DC-DC power converter of claim 30 wherein the isolated DC-DC power converter includes at least one primary winding, at least one secondary winding, and at least one inductor operatively coupled to the primary winding.

35. The DC-DC power converter of claim 30 wherein the isolated DC-DC power converter comprises a current-fed DC-DC power converter.

36. The DC-DC power converter of claim 35 wherein the current-fed DC-DC power converter is selected from the group consisting of a current-fed half-bridge DC-DC converter, a current-fed full-bridge DC-DC converter, a current fed push-pull DC-DC converter, and a current fed dual-forward converter.

37. The DC-DC power converter of claim 30 wherein the isolated DC-DC power converter comprises a single-ended converter.

38. A method of operating a DC-DC power converter, comprising the steps of:

in the event a first voltage is applied across first and second input terminals of a switch assembly, providing a second voltage having a value between the first voltage value and a reference value by at least one electrical element included in the switch assembly;

switchably applying the first voltage, the second voltage, and the reference voltage across first and second output terminals of the switch assembly by a switch subassembly, the switch subassembly including a plurality of switching elements and being operatively connected to the first input terminal, the second input terminal, and the electrical element;

receiving the first voltage, the second voltage, and the reference voltage applied across the first and second output terminals of the switch assembly by a second DC-DC power converter; and

generating at least one third voltage by the second DC-DC power converter.

39. The method of claim 38 wherein the providing step includes providing the second voltage by the at least one electrical element, the electrical element being selected from the group consisting of a capacitor, a battery, and a third DC-DC power converter.

40. The method of claim 38 wherein the receiving and generating steps include receiving the first voltage, the second voltage, and the reference voltage, and generating the at least one third voltage, by the second DC-DC power converter, the second DC-DC power converter comprising an isolated DC-DC power converter.

41. The method of claim 40 wherein the receiving and generating steps include receiving the first voltage, the second voltage, and the reference voltage, and generating the at least one third voltage, by the isolated DC-DC power converter, the isolated DC-DC power converter comprising a dual-ended power converter.

42. The method of claim 38 wherein the applying step includes switchably applying at least the first voltage and the second voltage across the first and second output terminals of the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being less than or equal to two times the first voltage minimum value, and wherein the respective switching elements operate according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with no deadtime.

43. The method of claim 38 wherein the applying step includes switchably applying the first voltage, the second voltage, and the reference voltage across the first and second output terminals of the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being greater than two times the first voltage minimum value, and wherein the respective switching elements operate according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with a predetermined amount of deadtime.

44. A DC-DC power converter, comprising:

a switch assembly including

first and second input terminals,

at least one electrical element connected to at least one of the first and second input terminals, the at least one electrical element being operative, in the event a first voltage is applied across the first and second input terminals, to provide a second voltage having a value between the first voltage value and a reference voltage value,

first and second output terminals, and

a switch subassembly including a plurality of switching elements, the switch subassembly being operatively connected to the first input terminal, the second input terminal, and the electrical element, wherein the switch subassembly is operative, in the event the first voltage is applied across the first and second input terminals, to switchably apply the first voltage, the second voltage, and the reference voltage across the first and second output terminals; and

a filter operatively connected to the first and second output terminals of the switch assembly, the filter being configured to receive the switchably applied first, second, and reference voltages, and to generate at least one third filtered voltage.

45. The DC-DC power converter of claim 44 further including a second DC-DC power converter operatively connected to the filter, the second DC-DC power converter being configured to receive the at least one third filtered voltage, and to generate at least one fourth voltage.

46. The DC-DC power converter of claim 44 wherein the electrical element is selected from the group consisting of a capacitor, a battery, and a third DC-DC power converter.

47. The DC-DC power converter of claim 44 wherein the switch assembly comprises:

first and second switching elements each having a first connection and a second connection, the first connection of the first switching element being connected to the second connection of the second switching element to form a first node, and the first node being connected to a first connection of the electrical element;

third and fourth switching elements, the third switching element being connected between the first input terminal and the second connection of the first switching element, and the fourth switching element being connected between the second input terminal and the first connection of the second switching element; and

wherein the second connection of the first switching element and the first connection of the second switching element are connected to the first and second output terminals, respectively.

48. The DC-DC power converter of claim 47 wherein the first and second switching elements comprise respective diodes.

49. The DC-DC power converter of claim 47 wherein the at least one electrical element includes first and second electrical elements, the first and second electrical elements being serially connected to form the first connection of the at least one electrical element.

50. The DC-DC power converter of claim 49 wherein the first and second electrical elements comprise respective capacitors.

51. The DC-DC power converter of claim 44 wherein the second DC-DC power converter comprises an isolated DC-DC power converter.

52. The DC-DC power converter of claim 51 wherein the isolated DC-DC power converter comprises a dual-ended power converter.

53. The DC-DC power converter of claim 52 wherein the dual-ended power converter is selected from the group consisting of a full-bridge converter, a half-bridge converter, a dual-forward converter, and a push-pull converter.

54. The DC-DC power converter of claim 51 wherein the isolated DC-DC power converter comprises a dual-forward converter.

55. The DC-DC power converter of claim 51 wherein the isolated DC-DC power converter includes at least one primary winding, at least one secondary winding, and at least one inductor operatively coupled to the primary winding.

56. The DC-DC power converter of claim 51 wherein the isolated DC-DC power converter comprises a current-fed DC-DC power converter.

57. The DC-DC power converter of claim 56 wherein the current-fed DC-DC power converter is selected from the group consisting of a current-fed half-bridge DC-DC converter, a current-fed full-bridge DC-DC converter, a current fed push-pull DC-DC converter, and a current fed dual-forward converter.

58. The DC-DC power converter of claim 51 wherein the isolated DC-DC power converter comprises a single-ended converter.

59. A method of operating a DC-DC power converter, comprising the steps of:

in the event a first voltage is applied across first and second input terminals of a switch assembly, providing a second voltage having a value between the first voltage value and a reference value by at least one electrical element included in the switch assembly;

switchably applying the first voltage, the second voltage, and the reference voltage across first and second output terminals of the switch assembly by a switch subassembly, the switch subassembly including a plurality of switching elements and being operatively connected to the first input terminal, the second input terminal, and the electrical element;

receiving the first voltage, the second voltage, and the reference voltage applied across the first and second output terminals of the switch assembly by a filter; and

generating at least one third filtered voltage by the filter.

60. The method of claim 59 further including the steps of

receiving the at least one third filtered voltage by a second DC-DC power converter;

and

generating at least one fourth voltage by the second DC-DC power converter.

61. The method of claim 59 wherein the providing step includes providing the second voltage by the at least one electrical element, the electrical element being selected from the group consisting of a capacitor, a battery, and a third DC-DC power converter.

62. The method of claim 59 wherein the second receiving step includes receiving the at least one third filtered voltage by the second DC-DC power converter, the second DC-DC power converter comprising an isolated DC-DC power converter.

63. The method of claim 62 wherein the second receiving step includes receiving the at least one third filtered voltage by the isolated DC-DC power converter, the isolated DC-DC power converter comprising a dual-ended power converter.

64. The method of claim 62 wherein the second receiving step includes receiving the at least one third filtered voltage by the isolated DC-DC power converter, the isolated DC-DC power converter comprising a dual forward converter.

65. The method of claim 59 wherein the applying step includes switchably applying at least the first voltage and the second voltage across the first and second output terminals of the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being less than or equal to two times the first voltage minimum value, and wherein the respective switching elements operate according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with no deadtime.

66. The method of claim 60 wherein the applying step includes switchably applying at least the first voltage and the second voltage across the first and second output terminals of the switch assembly, and wherein the respective switching elements operate according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with no deadtime.

67. The method of claim 59 wherein the applying step includes switchably applying the first voltage, the second voltage, and the reference voltage across the first and second output terminals of the switch assembly, wherein the first voltage has a minimum value and a maximum value, the first voltage maximum value being greater than two times the first voltage minimum value, and wherein the respective switching elements operate according to at least one predetermined duty ratio to allow the DC-DC power converter to operate with a predetermined amount of deadtime.