CN-122003809-A - Voltage balancing circuit with integrated brake chopper for series inverter

Abstract

A circuit includes a first power switch, a second power switch, a third power switch, and a fourth power switch in series to form a first branch in parallel with a second branch, the second branch including a first capacitor and a second capacitor in series with a first node between the first capacitor and the second capacitor. The first braking resistor is connected in series with the first chopper switch to form a third branch, and the second braking resistor is connected in parallel with the second chopper switch to form a fourth branch. The third branch is located between a terminal of the first capacitor and a second node located between the first power switch and the second power switch. The second power switch and the third power switch are provided with a third node therebetween. The fourth branch is located between the terminal of the second capacitor and a fourth node located between the third power switch and the fourth power switch. The third capacitor and/or inductor forms a fifth branch between (i) the second node and the fourth node or (ii) the first node and the third node.

Inventors

• Slavko Mosewick

Assignees

• ABB瑞士股份有限公司

Dates

Publication Date

20260508

Application Date

20231010

Claims (20)

1. 1. An integrated voltage balancing and braking chopper circuit, comprising: A first power switch, a second power switch, a third power switch, and a fourth power switch coupled in series to form a first leg, wherein the first leg is in parallel with a second leg comprising a first capacitor and a second capacitor coupled in series, and wherein the first capacitor and the second capacitor have a first node disposed therebetween; A first braking resistor coupled in series with a first chopper switch to form a third branch, wherein the third branch is coupled between a terminal of the first capacitor and a second node disposed between the first power switch and the second power switch, and wherein the second power switch and the third power switch have a third node disposed therebetween; A second braking resistor coupled in series with a second chopper switch to form a fourth branch, wherein the fourth branch is coupled between a terminal of the second capacitor and a fourth node disposed between the third power switch and the fourth power switch, and A third capacitor and/or inductor forming a fifth leg, wherein the fifth leg is coupled between (i) the second node and the fourth node, or (ii) the first node and the third node.
2. 2. The integrated voltage balancing and braking chopper circuit of claim 1, further comprising: A controller configured to modify operation of the first, second, third, and fourth power switches and the first and second chopper switches to (i) balance a first voltage of the first capacitor with a second voltage of the second capacitor with the third capacitor and/or the inductor, and (ii) dissipate energy stored in the first and second capacitors with the first and second braking resistors.
3. 3. The integrated voltage balancing and braking chopper circuit of claim 2 wherein the controller is further configured to: determining whether at least one of the first voltage and the second voltage is greater than a threshold voltage, and In response to determining that at least one of the first voltage and the second voltage is greater than the threshold voltage, at least one of the first chopper switch and the second chopper switch is closed to dissipate the energy stored in at least one of the first capacitor and the second capacitor.
4. 4. The integrated voltage balancing and braking chopper circuit of claim 3 wherein: the fifth branch comprises the third capacitor coupled in series with the inductor, The fifth branch is electrically coupled between the second node and the fourth node, and The controller is further configured to turn off the second and fourth power switches when the first and second chopper switches are closed.
5. 5. The integrated voltage balancing and braking chopper circuit of claim 3 wherein: the fifth branch comprises only the inductor, The inductor is coupled between the first node and the third node, and The controller is further configured to turn off the second and third power switches when the first and second chopper switches are closed.
6. 6. The integrated voltage balancing and braking chopper circuit of claim 3 wherein: said fifth branch comprises only said third capacitor, The third capacitor is coupled between the second node and the fourth node, and The controller is further configured to, when the first chopper switch and the second chopper switch are closed: simultaneously operating the second power switch and the fourth power switch, and Simultaneously and complementarily to the second and fourth power switches, the first and third power switches are operated.
7. 7. The integrated voltage balancing and braking chopper circuit of claim 1 wherein: the fifth branch includes the third capacitor coupled in series with the inductor, and The fifth leg is electrically coupled between the second node and the fourth node.
8. 8. The integrated voltage balancing and braking chopper circuit of claim 1 wherein: The fifth branch includes only the third capacitor, and The third capacitor is coupled between the second node and the fourth node.
9. 9. The integrated voltage balancing and braking chopper circuit of claim 1 wherein: the fifth branch includes only the inductor, and The inductor is coupled between the first node and the third node.
10. 10. The integrated voltage balancing and braking chopper circuit of claim 9 wherein: The third branch is coupled between the second node and the negative terminal of the first capacitor, and The fourth leg is coupled between the fourth node and a positive terminal of the second capacitor.
11. 11. The integrated voltage balancing and braking chopper circuit of claim 1 wherein: The third branch is coupled between the second node and the negative terminal of the first capacitor, and The fourth leg is coupled between the fourth node and a negative terminal of the second capacitor.
12. 12. The integrated voltage balancing and braking chopper circuit of claim 1 wherein: at least one of the first chopper switch and the second chopper switch comprises a mechanical switch.
13. 13. A drive system for an Alternating Current (AC) multiphase motor, the drive system comprising: A first inverter including a first capacitor; A second inverter comprising a second capacitor, wherein the first capacitor and the second capacitor are coupled in series to form a first leg, and wherein the first capacitor and the second capacitor have a first node disposed therebetween; An integrated voltage balancing and braking chopper circuit comprising: A first power switch, a second power switch, a third power switch, and a fourth power switch coupled in series to form a second branch, wherein the second branch is in parallel with the first branch; a first braking resistor coupled in series with a first chopper switch to form a third branch, wherein the third branch is coupled between a terminal of the first capacitor and a second node disposed between the first power switch and the second power switch, and wherein the third power switch and the fourth power switch have a third node disposed therebetween; A second braking resistor coupled in series with a second chopper switch to form a fourth branch, wherein the fourth branch is coupled between a terminal of the second capacitor and a fourth node disposed between the third power switch and the fourth power switch, and A third capacitor and/or inductor forming a fifth leg, wherein the fifth leg is coupled between (i) the second node and the fourth node, or (ii) the first node and the third node.
14. 14. The drive system of claim 13, further comprising: A controller configured to modify operation of the first, second, third, and fourth power switches and the first and second chopper switches to (i) balance a first voltage of the first capacitor with a second voltage of the second capacitor with the third capacitor and/or the inductor, and (ii) dissipate energy stored in the first and second capacitors with the first and second braking resistors.
15. 15. The drive system of claim 14, wherein the controller is further configured to: determining whether at least one of the first voltage and the second voltage is greater than a threshold voltage, and In response to determining that at least one of the first voltage and the second voltage is greater than the threshold voltage, at least one of the first chopper switch and the second chopper switch is closed to dissipate the energy stored in at least one of the first capacitor and the second capacitor.
16. 16. The drive system of claim 15, wherein: The fifth branch comprises the third capacitor in series with the inductor, The fifth branch is coupled between the second node and the fourth node, and The controller is further configured to turn off the second and fourth power switches when the first and second chopper switches are closed.
17. 17. The drive system of claim 15, wherein: the fifth branch comprises only the inductor, The inductor is coupled between the first node and the third node, and The controller is further configured to turn off the second and third power switches when the first and second chopper switches are closed.
18. 18. The drive system of claim 15, wherein: said fifth branch comprises only said third capacitor, The third capacitor is coupled between the second node and the fourth node, and The controller is further configured to, when the first chopper switch and the second chopper switch are closed: simultaneously operating the second power switch and the fourth power switch, and Simultaneously and complementarily to the second and fourth power switches, the first and third power switches are operated.
19. 19. The drive system of claim 14, wherein: at least one of the first chopper switch and the second chopper switch comprises a mechanical switch.
20. 20. An integrated voltage balancing and braking chopper circuit, comprising: A first power switch coupled between a positive terminal of the first capacitor and the first node; a second power switch coupled between the first node and a second node; a third power switch coupled between the second node and a third node; A fourth power switch coupled between the third node and a negative terminal of a second capacitor, wherein the first capacitor and the second capacitor are coupled in series; A first brake chopper coupled between the first node and one of the positive terminal of the first capacitor and a negative terminal of the first capacitor; a second brake chopper coupled between the third node and one of a positive terminal of the second capacitor and the negative terminal of the second capacitor, and A third capacitor and/or inductor coupled between (i) the first node and the third node, or (ii) the second node and a fourth node at a connection between the negative terminal of the first capacitor and the positive terminal of the second capacitor.

Description

Voltage balancing circuit with integrated brake chopper for series inverter Technical Field The field of the present disclosure relates to AC motor drives, and in particular to series inverters for powering multiphase AC motors. Background When a series inverter (SCI) powers a multiphase AC motor, one of the requirements is the voltage balancing of Direct Current (DC) link capacitors. Since DC link voltage balancing depends on the active power distribution between the inverter/winding sets, balancing methods are typically employed. The voltage balancing circuit is used with control modifications of the balancing method that exploit the introduction of unacceptable complexity at the SCI. Some examples of voltage balancing circuits include soft-switched resonant inductor capacitor-based (LC-based) circuits, switched capacitor-based (C-based) circuits, and inductor-based (L-based) circuits. Further, since a motor drive with a diode rectifier may enter a regenerative mode, a brake chopper is typically utilized. The use of a brake chopper in addition to the voltage balancing circuit for the SCI increases the complexity and components used to drive the multiphase AC motor, thereby increasing cost and reducing reliability. Therefore, it is desirable to improve the reliability and reduce the complexity of SCI for driving a multiphase AC motor. Disclosure of Invention In one aspect, an integrated voltage balancing and braking chopper circuit is provided. The circuit includes a first power switch, a second power switch, a third power switch, and a fourth power switch coupled in series to form a first leg, wherein the first leg is in parallel with the second leg, the second leg includes a first capacitor and a second capacitor coupled in series, and wherein the first capacitor and the second capacitor have a first node disposed therebetween. The circuit further includes a first braking resistor coupled in series with the first chopper switch to form a third leg, wherein the third leg is coupled between a terminal of the first capacitor and a second node disposed between the first power switch and the second power switch, and wherein the second power switch and the third power switch have a third node disposed therebetween. The circuit further includes a second braking resistor coupled in series with the second chopper switch to form a fourth branch, wherein the fourth branch is coupled between a terminal of the second capacitor and a fourth node disposed between the third power switch and the fourth power switch. The circuit further includes a third capacitor and/or inductor forming a fifth leg, wherein the fifth leg is coupled between (i) the second node and the fourth node, or (ii) the first node and the third node. In another aspect, a drive system for an AC multi-phase motor is provided. The drive system includes a first inverter including a first capacitor, a second inverter including a second capacitor, wherein the first capacitor and the second capacitor are coupled in series to form a first leg, and wherein the first capacitor and the second capacitor have a first node disposed therebetween. The drive system also includes an integrated voltage balancing and braking chopper circuit. The circuit includes a first power switch, a second power switch, a third power switch, and a fourth power switch coupled in series to form a second branch, wherein the second branch is in parallel with the first branch. The circuit further includes a first braking resistor coupled in series with the first chopper switch to form a third leg, wherein the third leg is coupled between a terminal of the first capacitor and a second node disposed between the first power switch and the second power switch, and wherein the third power switch and the fourth power switch have a third node disposed therebetween. The circuit further includes a second braking resistor coupled in series with the second chopper switch to form a fourth branch, wherein the fourth branch is coupled between a terminal of the second capacitor and a fourth node disposed between the third power switch and the fourth power switch. The circuit further includes a third capacitor and/or inductor forming a fifth leg, wherein the fifth leg is coupled between (i) the second node and the fourth node, or (ii) the first node and the third node. In another aspect, an integrated voltage balancing and braking chopper circuit is provided. The circuit includes a first power switch coupled between a positive terminal of a first capacitor and a first node, a second power switch coupled between the first node and a second node, a third power switch coupled between the second node and a third node, and a fourth power switch coupled between the third node and a negative terminal of a second capacitor, wherein the first capacitor and the second capacitor are coupled in series. The circuit also includes a first brake chopper coupled between the first node and one of a positive terminal of th