Multiphase DC to DC converter

• US 7,596,007 B2
• Filed: 10/13/2006
• Issued: 09/29/2009
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Astec International Limited (Emerson Electric Company)
• Original Assignee: Astec International Limited (Emerson Electric Company)
• Inventors: Beltran, Israel, Sigamani, James, Phadke, Vijay
• Primary Examiner(s): Riley; Shawn
• Application Number:
  US11/580,533
• Publication Number:
  US 20070086224A1
• Time in Patent Office: 1,082 Days
• Field of Search: 363/71, 363/89, 363/132, 363/127
• US Class Current: 363/71
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10

Abstract

A multiphase DC to DC converter includes an input, an output, at least first and second converters, an inductor, an output capacitor, and a drive circuit. The drive circuit is configured for switching the first and second converters with a predetermined phase shift therebetween. The output capacitor is operatively coupled between the first and second converters and the output. The inductor can be placed either at the input side or the output side. When placed at the input side, the inductor is operatively coupled between an input capacitor and the first and second converters. When placed at the output side, the inductor is operatively coupled between the first and second converters and the output capacitor. The multiphase DC to DC converter is capable of achieving lossless switching transitions and negligible ripple current in the output capacitor.

Claims

1. A multiphase DC to DC converter comprising an input, an output, at least first and second converters, an output inductor, an output capacitor, and a drive circuit, the first and second converters connected in parallel between said input and the output inductor, the first and second converters each including an isolation transformer having a primary winding and at least two power switches coupled to the primary winding, the drive circuit configured for switching the at least two power switches of each of the first and second converters at a duty cycle of approximately fifty percent (50%) with a short dead time therebetween, with the primary winding open circuited during the short dead time, and with a predetermined phase shift between the first and second converters, the output capacitor operatively coupled between the output inductor and the output.

2. The multiphase DC to DC converter of claim 1 wherein the drive circuit is configured to turn on the second converter when the output inductor is being charged by the first converter to thereby achieve substantially zero current transition during turn on of the second converter.

3. The multiphase DC to DC converter of claim 2 wherein the transformer of at least one of the converters includes a secondary winding coupled to at least one synchronous rectifier, and wherein the drive circuit is configured to turn on the synchronous rectifier shortly after turning on one of the power switches of such transformer.

4. The multiphase DC to DC converter of claim 3 wherein the drive circuit is further configured to turn off the synchronous rectifier shortly before turning off one of the power switches of such transformer.

5. The multiphase DC to DC converter of claim 2 wherein the first and second converters include first and second rectification circuits, respectively.

6. The multiphase DC to DC converter of claim 5 wherein the first and second rectification circuits comprise diode rectifiers.

7. The multiphase DC to DC converter of claim 5 wherein the first and second rectification circuits comprise synchronous rectifiers.

8. The multiphase DC to DC converter of claim 2 wherein the drive circuit is configured to provide substantially complementary control signals to said at least two power switches.

9. The multiphase DC to DC converter of claim 1 wherein the predetermined phase shift is about 90 degrees.

10. The multiphase DC to DC converter of claim 1 wherein the first and second converters employ the same topology.

11. The multiphase DC to DC converter of claim 10 wherein the first and second converters are half bridge converters.

12. The multiphase DC to DC converter of claim 10 wherein the first and second converters are full bridge converters.

13. The multiphase DC to DC converter of claim 1 wherein at least the first converter includes a center-tapped full wave rectifier.

14. The multiphase DC to DC converter of claim 1 wherein at least the first converter includes a bridge type rectifier.

15. The multiphase DC to DC converter of claim 1 wherein the first and second converters each include a blocking capacitor and a parasitic inductance in series with the primary winding.

16. The multiphase DC to DC converter of claim 15 wherein the parasitic inductance includes an external inductor.

17. The multiphase DC to DC converter of claim 15 wherein the parasitic inductance includes parasitic inductance reflected from a secondary side of the transformer.

18. The multiphase DC to DC converter of claim 15 wherein the parasitic inductance includes an external inductor and parasitic inductance reflected from a secondary side of the transformer.

19. The multiphase DC to DC converter of claim 15 wherein the blocking capacitor and parasitic inductance of each of the first and second converters are sufficient to cause a reflected load current in the primary winding to resonate back to zero during an on time of the power switches coupled to such primary winding.

20. The multiphase DC to DC converter of claim 19 wherein each transformer has a magnetizing inductance sufficient to achieve substantially zero voltage switching of its associated power switches during the short dead time.

21. A multiphase DC to DC converter comprising an input, an output, at least first and second converters, an output inductor, an output capacitor, and a drive circuit, the first and second converters each including an isolation transformer having a primary winding and at least two power switches coupled to the primary winding, the drive circuit configured for switching the at least two power switches at a fixed frequency with a dead time therebetween, with the primary winding open circuited during the dead time, and with a predetermined phase shift between the first and second converters, the output inductor operatively coupled to the first and second converters, and the output capacitor operatively coupled between the output inductor and the output.

22. A multiphase DC to DC converter comprising an input, an output, at least first and second converters, an output inductor, an output capacitor, and a drive circuit, the drive circuit configured for switching the first and second converters with a predetermined phase shift therebetween, the output inductor operatively coupled to the first and second converters, and the output capacitor operatively coupled between the output inductor and the output, the first and second converters each including an isolation transformer having a primary winding, at least two power switches coupled to the primary winding, and a blocking capacitor and a parasitic inductance in series with the primary winding, the blocking capacitor and parasitic inductance sufficient to cause a reflected load current in the primary winding to resonate back to zero during an on time of the power switches coupled to such primary winding.

23. The multiphase DC to DC converter of claim 22 wherein each transformer has a magnetizing inductance sufficient to achieve substantially zero voltage switching of its associated power switches during an off time of the power switches.