Converter and method for operating a converter

• US 10,707,780 B2
• Filed: 09/20/2017
• Issued: 07/07/2020
• Est. Priority Date: 09/22/2016
• Status: Active Grant

• Current Assignee: Celeroton Ag
• Original Assignee: Celeroton Ag
• Inventors: Oberholzer, Georg
• Primary Examiner(s): Berhane, Adolf D
• Application Number:
  US16/334,934
• Publication Number:
  US 20200021206A1
• Time in Patent Office: 1,021 Days
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 6/085 in a bridge configuration

Abstract

A converter having a negative DC terminal and a positive DC terminal; at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal, a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal; and a current measurement circuit having a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element.

Claims

1. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is connected to the at least three AC terminals and the negative DC terminal, and each lower branch and each lower switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal; and

wherein the current measurement circuit is configured to measure one of the AC currents flowing through one of the AC terminals by closing the associated switch of the current measurement circuit instead of the associated lower switch of the converter bridge.

2. The converter of claim 1, wherein the current measurement circuit is configured to guide a selected one of the AC currents through the current measurement element, based on information which AC current is the selected one received during operation of the converter.

3. The converter of claim 1,

wherein the current measurement element comprises a first terminal and a second terminal,

the first terminal of the current measurement element being connected to the negative DC terminal;

the current measurement circuit being able to connect each one of the at least three AC terminals to the first terminal of the current measurement element and to guide the AC current associated with the AC terminal that is connected to the first terminal of the current measurement element to flow through the current measurement element.

4. The converter of claim 1, wherein the current measurement circuit is connected to the at least three AC terminals and the positive DC terminal, and each upper branch and each upper switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal.

5. The converter of claim 4, wherein the current measurement circuit is configured to measure one of the AC currents flowing through one of the AC terminals by closing the associated switch of the current measurement circuit instead of the associated upper switch of the converter bridge.

6. The converter of claim 1,

wherein the current measurement element comprises a first terminal and a second terminal,

the first terminal of the current measurement element being connected to the positive DC terminal;

the current measurement circuit being able to connect each one of the at least three AC terminals to the first terminal of the current measurement element and to guide the AC current associated with the AC terminal that is connected to the first terminal of the current measurement element to flow through the current measurement element.

7. The converter of claim 1, comprising a controller arranged to operate the converter bridge by driving switches of the converter bridge and to measure an AC current flowing through a selected one of the at least three AC terminals by closing a switch of the current measurement circuit that is connected to the selected AC terminal in place of a switch of the converter bridge that is connected to the selected AC terminal.

8. A method for operating the converter of claim 1, comprising the steps of:

operating the converter bridge by switching the AC currents flowing through the at least three AC terminals;

measuring a selected one of the AC currents by guiding it through the current measurement circuit instead of the converter bridge.

9. The method of claim 8, comprising the steps of:

operating the converter bridge by driving switches of the converter bridge;

measuring an AC current flowing through a selected one of the at least three AC terminals by closing a switch of the current measurement circuit that is connected to the selected AC terminal in place of an associated switch of the converter bridge that is connected to the selected AC terminal.

10. The method of claim 9, wherein the converter is driven by a six-step modulation scheme, in which each one of a set of switches of the converter bridge that have associated switches of the current measurement circuit is scheduled to remain closed during 60°

intervals of a 360°

interval after which the modulation scheme repeats, comprising the step of;

closing, during said 60°

intervals, instead of the switch of the converter bridge scheduled to remain closed, the associated switch of the current measurement circuit.

11. The method of claim 9, wherein the converter is driven by a sinusoidal commutation control scheme.

12. The converter of claim 2,

wherein the current measurement element comprises a first terminal and a second terminal,

the first terminal of the current measurement element being connected to the negative DC terminal;

the current measurement circuit being able to connect each one of the at least three AC terminals to the first terminal of the current measurement element and to guide the AC current associated with the AC terminal that is connected to the first terminal of the current measurement element to flow through the current measurement element.

13. The converter of claim 2, wherein the current measurement circuit is connected to the at least three AC terminals and the positive DC terminal, and each upper branch and each upper switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal.

14. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is connected to the at least three AC terminals and the positive DC terminal, and each upper branch and each upper switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal;

wherein the current measurement circuit is configured to measure one of the AC currents flowing through one of the AC terminals by closing the associated switch of the current measurement circuit instead of the associated upper switch of the converter bridge.

15. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

and further comprising a controller arranged to operate the converter bridge by driving switches of the converter bridge and to measure an AC current flowing through a selected one of the at least three AC terminals by closing a switch of the current measurement circuit that is connected to the selected AC terminal in place of a switch of the converter bridge that is connected to the selected AC terminal.

16. A method for operating converter, said converter comprising:

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

the method comprising the steps of;

operating the converter bridge by switching the AC currents flowing through the at least three AC terminals;

measuring a selected one of the AC currents by guiding it through the current measurement circuit instead of the converter bridge.

17. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is configured to guide a selected one of the AC currents through the current measurement element, based on information which AC current is the selected one received during operation of the converter,

wherein the current measurement circuit is connected to the at least three AC terminals and the negative DC terminal, and each lower branch and each lower switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal.

18. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is configured to guide a selected one of the AC currents through the current measurement element, based on information which AC current is the selected one received during operation of the converter,

wherein the current measurement element comprises a first terminal and a second terminal,

the first terminal of the current measurement element being connected to the negative DC terminal;

the current measurement circuit being able to connect each one of the at least three AC terminals to the first terminal of the current measurement element and to guide the AC current associated with the AC terminal that is connected to the first terminal of the current measurement element to flow through the current measurement element.

19. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is connected to the at least three AC terminals and the negative DC terminal, and each lower branch and each lower switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal;

wherein the current measurement element comprises a first terminal and a second terminal,

the first terminal of the current measurement element being connected to the negative DC terminal;

the current measurement circuit being able to connect each one of the at least three AC terminals to the first terminal of the current measurement element and to guide the AC current associated with the AC terminal that is connected to the first terminal of the current measurement element to flow through the current measurement element.

20. A converter, comprising

a negative DC terminal and a positive DC terminal;

at least three AC terminals, each AC terminal being arranged for an associated AC current to flow through the terminal;

a converter bridge with at least three bridge legs, each bridge leg being associated with one of the at least three AC terminals and being able to connect the associated AC terminal to the negative DC terminal or the positive DC terminal;

wherein the converter comprises

a current measurement circuit comprising a current measurement element, the current measurement circuit being configured to guide either none or one or more of the AC currents flowing through one of the at least three AC terminals through the current measurement element;

wherein the current measurement circuit is configured to guide a selected one of the AC currents through the current measurement element, based on information which AC current is the selected one received during operation of the converter

wherein the current measurement circuit is connected to the at least three AC terminals and the positive DC terminal, and each upper branch and each upper switch of the converter bridge have an associated switch of the current measurement circuit, which is connected to the same AC terminal.