System and method for operating power converters

Patent metadata

Field	Value
Publication number	US-2016156276-A1
Application number	US-201414555956-A
Country	US
Kind code	A1
Filing date	Nov 28, 2014
Priority date	Nov 28, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

An electrical circuit for a power converter includes a first switching device proximate an AC source. The circuit also includes a voltage measurement device proximate a DC link and extends between the AC source and the DC link. The circuit further includes a DC voltage source and a first capacitive device. The first capacitive device is positioned between the first switching device and the voltage measurement device. The circuit further includes a second switching device positioned between the first capacitive device and the voltage measurement device. The circuit also includes a controller operatively coupled to the DC voltage source, the voltage measurement device, and the switching devices. The controller is configured to open the second switching device when a measured voltage signal generated by the voltage measurement device is substantially representative of a reference voltage value.

First claim

What is claimed is:

1 . An electrical circuit for a power converter, said electrical circuit comprising:
an electrically conductive element; a first switching device coupled to said electrically conductive element proximate an alternating current (AC) source; a voltage measurement device coupled to said electrically conductive element proximate a direct current (DC) link, wherein said electrical circuit extends between the AC source and the DC link; a DC voltage source coupled to said electrically conductive element; a first capacitive device coupled to said electrically conductive element, said first capacitive device positioned between said first switching device and said voltage measurement device; a second switching device coupled to said electrically conductive element, said second switching device positioned between said first capacitive device and said voltage measurement device; and a controller operatively coupled to said DC voltage source, said voltage measurement device, said first switching device, and said second switching device, said controller configured to open said second switching device when a measured voltage signal generated by said voltage measurement device is substantially representative of a reference voltage value.

2 . The electrical circuit in accordance with claim 1 , wherein said electrically conductive element comprises a first electrically conductive element coupled to at least a positive DC rail and a second electrically conductive element coupled to at least a negative DC rail, said voltage measurement device configured to measure the voltage across at least one DC link device extending between said positive DC rail and said negative DC rail.

3 . The electrical circuit in accordance with claim 1 , wherein said first switching device is configured to isolate said electrical circuit from the AC source.

4 . The electrical circuit in accordance with claim 1 , wherein said DC voltage source is a DC pre-charger configured to energize said electrical circuit with a predetermined voltage value.

5 . The electrical circuit in accordance with claim 1 further comprising:
a second capacitive device coupled to said electrically conductive element; and
a third switching device coupled to said electrically conductive element, said second capacitive device positioned between said second switching device and said third switching device, and said third switching device positioned between said second capacitive device and said voltage measurement device.

6 . The electrical circuit in accordance with claim 5 , wherein said first capacitive device, said second switching device, said second capacitive device, and said third switching device define a plurality of said switching devices and a plurality of said capacitive devices alternating is a nested configuration.

7 . The electrical circuit in accordance with claim 6 , wherein said plurality of said switching devices and said plurality of said capacitive devices alternating in a nested configuration are configured to sequentially energize each of said capacitive devices of said plurality of capacitive devices to an associated predetermined voltage.

8 . The electrical circuit in accordance with claim 1 , wherein said controller comprises a comparator device.

9 . The electrical circuit in accordance with claim 1 , wherein said controller comprises a computer comprising a processor and a memory device coupled to said processor.

10 . A method of operating a power converter including an electrical circuit, the electrical circuit including a first potion proximate an alternating current (AC) source and a second portion proximate a direct current (DC) link, said method comprising:
opening a first switching device proximate the first portion, thereby substantially electrically isolating the electrical circuit from the AC source; inducing a DC voltage proximate the second portion; charging a first capacitive device to a first predetermined voltage value, the first capacitive device positioned between the first switching device and a second switching device; measuring the voltage proximate the second portion; and opening the second switching device when the measured voltage induced at the second portion is substantially equal to a first reference voltage value.

11 . The method in accordance with claim 10 , wherein inducing a DC voltage proximate the second portion comprises energizing a DC pre-charger device.

12 . The method in accordance with claim 10 further comprising:
charging a second capacitive device to a second predetermined voltage value, the second capacitive device positioned between the second switching device and a third switching device; and
opening the third switching device when the measured voltage induced at the second portion is substantially equal to a second reference voltage value.

13 . The method in accordance with claim 10 , wherein charging a first capacitive device and opening the second switching device comprises sequentially energizing each capacitive device of a plurality of capacitive devices and sequentially opening each second switching device when a corresponding measured voltage induced at the second portion is substantially equal to a corresponding reference voltage value.

14 . The method in accordance with claim 10 , wherein measuring the voltage proximate the second portion comprises measuring the voltage across at least one DC link device extending between a positive DC rail and a negative DC rail.

15 . An electric power system comprising:
an alternating current (AC) source; a direct current (DC) link; and a first power converter comprising an electrical circuit extending between said AC source and said DC link, said electrical circuit comprising:
an electrically conductive element;
a first switching device coupled to said electrically conductive element proximate said AC source;
a voltage measurement device coupled to said electrically conductive element proximate said DC link, wherein said electrical circuit extends between said AC source and said DC link;
a DC voltage source coupled to said electrically conductive element;
a first capacitive device coupled to said electrically conductive element, said first capacitive device positioned between said first switching device and said voltage measurement device;
a second switching device coupled to said electrically conductive element, said second switching device positioned between said first capacitive device and said voltage measurement device; and
a controller operatively coupled to said DC voltage source, said voltage measurement device, said first switching device, and said second switching device, said controller configured to open said second switching device when a measured voltage signal generated by said voltage measurement device is substantially representative of a reference voltage value.

16 . The electric power system in accordance with claim 15 further comprising a second power converter coupled to said DC link, said second power converter substantially similar to said first power converter.

17 . The electric power system in accordance with claim 15 , wherein said first power converter and said second power converter are multilevel power converters.

18 . The electric power system in accordance with claim 15 further comprising:
a second capacitive device coupled to said electrically conductive element; and
a third switching device coupled to said electrically conductive element, said second capacitive device positioned between said sec

Assignees

• Gen Electric

Inventors

• Yuan Zhihui
• Chen Qingyun
• Schroeder Stefan
• Shen Jie

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title

• H02M5/458 Primary

  using semiconductor devices only · CPC title

• H02M5/45

  using semiconductor devices only · CPC title

• H02M5/44 Primary

  using discharge tubes or semiconductor devices to convert the intermediate DC into AC · CPC title