Rectifier for converting three-phase AC voltage to 12-pulse DC voltage

Patent metadata

Field	Value
Publication number	US-9837926-B2
Application number	US-201314425049-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Sep 5, 2012
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A rectifier is configured to convert a three-phase AC voltage to a 12-pulse DC voltage, drawing a 12-pulse AC current from a three-phase network. The rectifier may comprise a first interleaved phase-leg, a second interleaved phase-leg, and/or a third interleaved phase-leg. Respective interleaved phase-legs may comprise positive portions configured to conduct positive current from a transformer towards a load, and negative portions configured to conduct negative current from the load back to the transformer. The rectifier may be configured to sequentially cycle respective interleaved phase-legs into positive and/or negative 120 conducting states over a 360 degree cycle to output the 12-pulse DC voltage. For example, during a first 120 degree conducting state a positive portion of the first interleaved phase-leg may conduct positive current towards the load, while a negative portion of a different phase-leg may conduct negative current back to the transformer.

First claim

What is claimed is:

1. A system for converting a three-phase AC voltage to a 12-pulse DC voltage, comprising:
a transformer configured to convert a three-phase AC voltage into a first set of phase voltages, a second set of phase voltages, and a third set of phase voltages; and
a rectifier comprising a first phase-leg electrically coupled to the first set of phase voltages, a second phase-leg electrically coupled to the second set of phase voltages, and a third phase-leg electrically coupled to the third set of phase voltages, the rectifier configured to sequentially cycle respective phase-legs into 120 degree conducting states over a 360 degree cycle to output a 12-pulse DC voltage, wherein each of the phase legs comprise:
a positive portion comprising a first positive diode, a second positive diode, and a main positive diode configured to conduct current towards a load, wherein an output of the first positive diode and an output of the second positive diode are electrically coupled to an input of the main positive diode; and
a negative portion comprising a first negative diode, a second negative diode, and a main negative diode configured to conduct negative current from the load, wherein an output of the main negative diode is electrically coupled to an input of the first negative diode and an input of the second negative diode, wherein a positive portion of a phase-leg is configured to conduct towards the load while a negative portion of a different phase leg is conducting from the load during a 120 degree conducting state.

2. The system of claim 1 , the first positive diode associated with a first high voltage of the first set of phase voltages and the second positive diode associated with a first low voltage of the first set of phase voltages.

3. The system of claim 2 , the first high voltage comprising a high magnitude that is greater than a low magnitude of the first low voltage, and the first low voltage comprising a first phase that is 60 degrees shifted from a second phase of the first high voltage.

4. The system of claim 1 , the main positive diode configured to conduct current from the first positive diode and the second positive diode towards the load.

5. The system of claim 1 , the main negative diode configured to conduct current from the load towards the first negative diode and the second negative diode.

6. The system of claim 1 , the first negative diode associated with a first high voltage of the first set of phase voltages and the second negative diode associated with a first low voltage of the first set of phase voltages.

7. The system of claim 1 , the transformer configured to:
output six phase voltages, shifted by 60 degrees with respect to one another, to the rectifier.

8. The system of claim 1 , the rectifier configured to:
perform a first 120 degree conducting state where a positive portion of the first phase-leg conducts towards the load while a negative portion of the second phase-leg or the third phase-leg conducts from the load;
perform a second 120 degree conducting state where a positive portion of the second phase-leg conducts towards the load while a negative portion of the first phase-leg or the third phase-leg conducts from the load; and
perform a third 120 degree conducting state where a positive portion of the third phase-leg conducts towards the load while a negative portion of the first phase-leg or the second phase-leg conducts from the load.

9. The system of claim 1 , the second phase-leg comprising a second positive portion and a second negative portion, the second positive portion comprising a third positive diode, a fourth positive diode, and a second main positive diode, the second negative portion comprising a third negative diode, a fourth negative diode, and a second main negative diode.

10. The system of claim 9 , the third phase-leg comprising a third positive portion and a third negative portion, the third positive portion comprising a fifth positive diode, a sixth positive diode, and a third main positive diode, the third negative portion comprising a fifth negative diode, a sixth negative diode, and a third main negative diode.

11. The system of claim 1 , the rectifier configured to conduct current from the transformer, through the positive portion, to a positive DC voltage rail during a positive 120 degree conducting state.

12. A method for converting a three-phase AC voltage to a 12-pulse DC voltage, comprising:
performing a 360 degree cycle to output a 12-pulse DC voltage from a rectifier to a load based upon a three-phase AC input, wherein the rectifier comprises a first phase-leg electrically coupled to a first set of phase voltages, a second phase-leg electrically coupled to a second set of phase voltages, and a third phase-leg electrically coupled to a third set of phase voltages, wherein each of the phase legs comprise:
a positive portion comprising a first positive diode, a second positive diode, and a main positive diode configured to conduct current towards the load, wherein an output of the first positive diode and an output of the second positive diode are electrically coupled to an input of the main positive diode; and
a negative portion comprising a first negative diode, a second negative diode, and a main negative diode configured to conduct current from the load, wherein an output of the main negative diode is electrically coupled to an input of the first negative diode and an input of the second negative diode, wherein the performing the 360 degree cycle comprises:
performing a first 120 degree conducting state where a positive portion of the first phase-leg conducts towards the load while a negative portion of the second phase-leg or the third phase-leg conducts from the load;
performing a second 120 degree conducting state where a positive portion of the second phase-leg conducts towards the load while a negative portion of the first phase-leg or the third phase-leg conducts from the load; and
performing a third 120 degree conducting state where a positive portion of the third phase-leg conducts towards the load while a negative portion of the first phase-leg or the second phase-leg conducts from the load.

13. The method of claim 12 , comprising:
sequentially cycling the first phase-leg, the second phase-leg, and the third phase-leg through 120 degree conducting states.

14. The method of claim 12 , comprising:
conducting current, through the main positive diode, from the first positive diode and the second positive diode towards the load.

15. The method of claim 12 , comprising:
conducting current from a transformer, through the positive portion, to a positive DC voltage rail during a positive 120 degree conducting state.

16. The method of claim 12 , comprising:
outputting, from a transformer, six phase voltages, shifted by 60 degrees with respect to one another, to the rectifier.

17. The method of claim 12 , comprising:
sequentially cycling the first phase-leg, the second phase-leg, and a third phase-leg of the rectifier into 120 degree conducting states over the 360 degree cycle to output the 12-pulse DC voltage.

18. The method of claim 12 , wherein the performing a first 120 degree conducting state comprises:
conducting current from the load using a negative portion of the second phase-leg and not negative portions of the first phase-leg and the second phase-leg.

19. The method of claim 18 , wherein the performing a first 120 degree conducting state comprises:
conducting current through the positive portion of the first phase-leg and no

Assignees

• Abb Technology Ag
• Burgos Rolando
• Abb Schweiz Ag

Inventors

• Burgos Rolando

Classifications

• H02M7/08 Primary

  arranged for operation in parallel · CPC title

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• H02M7/066

  particular circuits having a special characteristic · CPC title

• H02M7/062

  Avoiding or suppressing excessive transient voltages or currents · CPC title

• H02M7/06

  using discharge tubes without control electrode or semiconductor devices without control electrode · CPC title