SWITCHING BRANCH FOR THREE-LEVEL CONVERTER AND METHOD FOR CONTROLLING SWITCHING BRANCH OF THREE-LEVEL CONVERTER

• US 20120120698A1
• Filed: 11/03/2011
• Published: 05/17/2012
• Est. Priority Date: 11/17/2010
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: Abb Oy (ABB Limited)
• Inventors: VIITANEN, Tero
• Granted Patent: US 9,088,225 B2
• Time in Patent Office: Days
• US Class Current: 363/126
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters

Abstract

Exemplary embodiments for controlling a switching branch for a three-level converter, and a switching branch are disclosed. A first semiconductor switch and a second semiconductor switch, a first diode and a second diode, a third semiconductor switch and a fourth semiconductor switch, a third diode, and a fourth diode, a fifth semiconductor switch and a sixth semiconductor switch, a fifth diode, and a sixth diode, and a control arrangement for controlling the semiconductor switches are provided. The first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module, and the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module.

Claims

1. A switching branch for a three-level converter, the switching branch comprising:

a first semiconductor switch and a second semiconductor switch connected in series between a positive direct current pole and an alternating current pole of the switching branch;

a first diode connected in parallel to the first semiconductor switch, and a second diode connected in parallel to the second semiconductor switch;

a third semiconductor switch and a fourth semiconductor switch connected in series between a negative direct current pole and the alternating current pole of the switching branch;

a third diode connected in parallel to the third semiconductor switch, and a fourth diode connected in parallel to the fourth semiconductor switch;

a fifth semiconductor switch connected between a neutral direct current pole and a connection point between the first and second semiconductor switches;

a sixth semiconductor switch connected between the neutral direct current pole and a connection point between the third and fourth semiconductor switches;

a fifth diode connected in parallel to the fifth semiconductor switch, and a sixth diode connected in parallel to the sixth semiconductor switch; and

a control arrangement for controlling the semiconductor switches,

wherein the first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module,

wherein, the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module, and

wherein the control arrangement is configured to perform at least one of;

control each semiconductor switch, when the converter operates as a rectifier, such that when a current flows into the switching branch through the alternating current pole, said current always flows through either the first diode or the fifth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fourth diode or the sixth semiconductor switch; and

control each semiconductor switch, when the converter operates as an inverter, such that when a current flows into the switching branch through the alternating current pole, said current always flows through either the sixth diode or the fourth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fifth diode or the first semiconductor switch.

2. The switching branch for a three-level converter of claim 1, wherein the second semiconductor switch, the second diode, the third semiconductor switch and the third diode reside in a third switching branch-specific semiconductor module.

3. The switching branch for a three-level converter of claim 1, wherein

the second semiconductor switch and the second diode reside in the first switching branch-specific semiconductor module;

and

the third semiconductor switch and the third diode reside in the second switching branch-specific semiconductor module.

4. A three-phase three-level converter, comprising:

three switching branches, wherein each switching branch includes;

a first semiconductor switch and a second semiconductor switch connected in series between a positive direct current pole and an alternating current pole of the switching branch;

a first diode connected in parallel to the first semiconductor switch, and a second diode connected in parallel to the second semiconductor switch;

a third semiconductor switch and a fourth semiconductor switch connected in series between a negative direct current pole and the alternating current pole of the switching branch;

a third diode connected in parallel to the third semiconductor switch, and a fourth diode connected in parallel to the fourth semiconductor switch;

a fifth semiconductor switch connected between a neutral direct current pole and a connection point between the first and second semiconductor switches;

a sixth semiconductor switch connected between the neutral direct current pole and a connection point between the third and fourth semiconductor switches;

a fifth diode connected in parallel to the fifth semiconductor switch, and a sixth diode connected in parallel to the sixth semiconductor switch; and

a control arrangement for controlling the semiconductor switches,

wherein the first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module,

wherein, the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module, and

wherein the control arrangement is configured to perform at least one of;

control each semiconductor switch, when the converter operates as a rectifier, such that when a current flows into the switching branch through the alternating current pole, said always current flows through either the first diode or the fifth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fourth diode or the sixth semiconductor switch; and

control each semiconductor switch, when the converter operates as an inverter, such that when a current flows into the switching branch through the alternating current pole, said current always flows through either the sixth diode or the fourth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fifth diode or the first semiconductor switch.

5. The converter of claim 4, wherein positive direct current poles of each switching branch are connected together, negative direct current poles of each switching branch are connected together and neutral direct current poles of each switching branch are connected together.

6. A method for controlling a switching branch of a three-level converter, the switching branch comprising:

a first semiconductor switch and a second semiconductor switch connected in series between a positive direct current pole and an alternating current pole of the switching branch;

a first diode connected in parallel to the first semiconductor switch, and a second diode connected in parallel to the second semiconductor switch;

a third semiconductor switch and a fourth semiconductor switch connected in series between a negative direct current pole and the alternating current pole of the switching branch;

a third diode connected in parallel to the third semiconductor switch, and a fourth diode connected in parallel to the fourth semiconductor switch;

a fifth semiconductor switch connected between a neutral direct current pole and a connection point between the first and second semiconductor switches;

a sixth semiconductor switch connected between the neutral direct current pole and a connection point between the third and fourth semiconductor switches; and

a fifth diode connected in parallel to the fifth semiconductor switch, and a sixth diode connected in parallel to the sixth semiconductor switch,

wherein the first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module; and

wherein the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module, the method comprising;

controlling each semiconductor switch, when the converter operates as a rectifier, such that when a current flows into the switching branch through the alternating current pole, said current always flows through either the first diode or the fifth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fourth diode or the sixth semiconductor switch.

7. The method of claim 6, wherein the second semiconductor switch, the second diode, the third semiconductor switch and the third diode reside in a third switching branch-specific semiconductor module.

8. The method of claim 6, wherein

the second semiconductor switch and the second diode reside in the first switching branch-specific semiconductor module;

and

the third semiconductor switch and the third diode reside in the second switching branch-specific semiconductor module.

9. A computer program product comprising computer program code recorded on a non-transitory computer readable medium, wherein when the computer readable medium is in a computer execution of the program code causes the computer to carry out the steps of a method for controlling a switching branch of a three-level converter, the switching branch comprising:

a first semiconductor switch and a second semiconductor switch connected in series between a positive direct current pole and an alternating current pole of the switching branch;

a first diode connected in parallel to the first semiconductor switch, and a second diode connected in parallel to the second semiconductor switch;

a third semiconductor switch and a fourth semiconductor switch connected in series between a negative direct current pole and the alternating current pole of the switching branch;

a third diode connected in parallel to the third semiconductor switch, and a fourth diode connected in parallel to the fourth semiconductor switch;

a fifth semiconductor switch connected between a neutral direct current pole and a connection point between the first and second semiconductor switches;

a sixth semiconductor switch connected between the neutral direct current pole and a connection point between the third and fourth semiconductor switches; and

a fifth diode connected in parallel to the fifth semiconductor switch, and a sixth diode connected in parallel to the sixth semiconductor switch, wherein the first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module; and

wherein the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module, the method comprising;

controlling each semiconductor switch, when the converter operates as a rectifier, such that when a current flows into the switching branch through the alternating current pole, said current always flows through either the first diode or the fifth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current always flows through either the fourth diode or the sixth semiconductor switch.

10. A method for controlling a switching branch of a three-level converter, the switching branch comprising:

a first semiconductor switch and a second semiconductor switch connected in series between a positive direct current pole and an alternating current pole of the switching branch;

a first diode connected in parallel to the first semiconductor switch, and a second diode connected in parallel to the second semiconductor switch;

a third semiconductor switch and a fourth semiconductor switch connected in series between a negative direct current pole and the alternating current pole of the switching branch;

a third diode connected in parallel to the third semiconductor switch, and a fourth diode connected in parallel to the fourth semiconductor switch;

a fifth semiconductor switch connected between a neutral direct current pole and a connection point between the first and second semiconductor switches;

a sixth semiconductor switch connected between the neutral direct current pole and a connection point between the third and fourth semiconductor switches; and

a fifth diode connected in parallel to the fifth semiconductor switch, and a sixth diode connected in parallel to the sixth semiconductor switch,

wherein the first semiconductor switch, the first diode, the fifth semiconductor switch and the fifth diode reside in a first switching branch-specific semiconductor module; and

wherein the fourth semiconductor switch, the fourth diode, the sixth semiconductor switch and the sixth diode reside in a second switching branch-specific semiconductor module, the method comprising;

controlling the semiconductor switches, when the converter operates as an inverter, such that when a current flows into the switching branch through the alternating current pole, said current flows through either the sixth diode or the fourth semiconductor switch, and such that when a current flows out of the switching branch through the alternating current pole, said current flows through either the fifth diode or the first semiconductor switch.