Enhanced common mode current reduction in three-phase inductors, transformers, and motor drive systems

Patent metadata

Field	Value
Publication number	US-10283262-B2
Application number	US-201715787254-A
Country	US
Kind code	B2
Filing date	Oct 18, 2017
Priority date	Oct 18, 2016
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

Enhanced common mode current reduction in three-phase inductors, transformers, and motor drive systems. A motor drive system includes an iron core transformer, a common-mode transformer coupled to a three-phase motor, and a variable speed drive providing a three-phase power signal to drive the three-phase motor, and coupled to the iron core transformer and the common mode transformer. The system includes a DC bus having a DC bus midpoint. The common-mode transformer includes a toroidal ferrite core, a first choke winding, a second choke winding, a third choke winding, a first coupling winding collocated with the first choke winding, a second coupling winding collocated with the second choke winding, and a third coupling winding collocated with the third choke winding. The first, second, and third coupling windings are coupled in parallel to one another. The coupled windings couple a neutral point of the iron core transformer to the DC bus midpoint.

First claim

What is claimed is:

1. A common mode inductor comprising:
a core;
a first winding pair wound on a first portion of the core, wherein the first winding pair includes a first choke winding and a first coupling winding that is electrically isolated from the first choke winding, and further wherein the first choke winding and the first coupling winding have an identical number of turns and are wound in the same direction;
a second winding pair wound on a second portion of the core, wherein the second winding pair includes a second choke winding and a second coupling winding that is electrically isolated from the second choke winding, and further wherein the second choke winding and the second coupling winding have an identical number of turns and are wound in the same direction; and
a third winding pair wound on a third portion of the core, wherein the third winding pair includes a third choke winding and a third coupling winding that is electrically isolated from the third choke winding, and further wherein the third choke winding and the third coupling winding have an identical number of turns and are wound in the same direction.

2. The inductor of claim 1 , wherein
the first choke winding and the first coupling winding are both wound around a first portion of the core;
the second choke winding and the second coupling winding are both wound around a second portion of the core;
the third choke winding and the third coupling winding are both wound around a third portion of the core; and
the first portion, the second portion, and the third portion are distinct from one another.

3. The inductor of claim 1 , wherein the first, second, and third coupling windings and the first, second, and third choke windings have an identical number of turns about the core.

4. The inductor of claim 1 , wherein the first coupling winding, the second coupling winding, and the third coupling winding are electrically coupled to one another in parallel.

5. The inductor of claim 1 , further comprising:
an insulation barrier positioned between the first, second, and third coupling windings and the first, second, and third choke windings.

6. The inductor of claim 1 , wherein the first choke winding, the second choke winding, and the third choke winding are wound from insulated conductors each having a first gauge.

7. The inductor of claim 6 , wherein the first coupling winding, the second coupling winding, and the third coupling winding are wound from insulated conductors each having a second gauge,
wherein the second gauge is lower than the first gauge.

8. The inductor of claim 1 , wherein at least one of the group consisting of the first, second, and third coupling windings and the first, second, and third choke windings is wound from an insulated conductor that includes multiple strands of wire.

9. The inductor of claim 1 , wherein the core one selected from the group consisting of a toroidal ferrite core, a toroidal steel core, and a toroidal powder core.

10. A drive system for a three-phase motor, the system comprising:
a set of filter inductors;
a capacitor neutral star connection coupled to the set of filter inductors;
a common-mode transformer coupled to the three-phase motor;
a variable speed drive coupled to the iron core transformer and the common mode transformer, the variable speed drive providing a three-phase power signal to drive the three-phase motor; and
a DC bus having a DC bus midpoint;
wherein the common-mode transformer includes
a toroidal ferrite core,
a first choke winding,
a second choke winding,
a third choke winding,
a first coupling winding collocated with the first choke winding,
a second coupling winding collocated with the second choke winding, and
a third coupling winding collocated with the third choke winding,

wherein the first, second, and third coupling windings are coupled in parallel to one another, and
wherein the coupled windings couple a neutral point of the capacitor neutral star connection to the DC bus midpoint.

11. The drive system of claim 10 , wherein
the first coupling winding that is electrically isolated from the first choke winding and wound in the same sense as the first choke winding;
the second coupling winding is electrically isolated from the second choke winding and wound in the same sense as the second choke winding; and
the third coupling winding is electrically isolated from the third choke winding and wound in the same sense as the third choke winding.

12. The drive system of claim 10 , wherein
the first choke winding and the first coupling winding are both wound around a first portion of the toroidal ferrite core;
the second choke winding and the second coupling winding are both wound around a second portion of the toroidal ferrite core;
the third choke winding and the third coupling winding are both wound around a third portion of the toroidal ferrite core; and
the first portion, the second portion, and the third portion are distinct from one another.

13. The drive system of claim 10 , wherein the first, second, and third coupling windings and the first, second, and third choke windings have an identical number of turns about the toroidal ferrite core.

14. The drive system of claim 10 , wherein the common-mode transformer further includes an insulation barrier positioned between the first, second, and third coupling windings and the first, second, and third choke windings.

15. The drive system of claim 10 , wherein the first choke winding, the second choke winding, and the third choke winding are wound from insulated conductors each having a first gauge.

16. The drive system of claim 14 , wherein the first coupling winding, the second coupling winding, and the third coupling winding are wound from insulated conductors each having a second gauge,
wherein the second gauge is lower than the first gauge.

17. The drive system of claim 10 , wherein at least one of the group consisting of the first, second, and third coupling windings and the first, second, and third choke windings is wound from an insulated conductor that includes multiple strands of wire.

18. A common mode transformer comprising:
a toroidal ferrite core;
a first choke winding;
a second choke winding;
a third choke winding;
a first coupling winding collocated with the first choke winding;
a second coupling winding collocated with the second choke winding; and
a third coupling winding collocated with the third choke winding,
wherein the first, second, and third coupling windings are coupled in parallel to one another;
wherein the first coupling winding is electrically isolated from the first choke winding, and further wherein the first choke winding and the first coupling winding have an identical number of turns and are wound in the same direction;
wherein the second coupling winding is electrically isolated from the second choke winding, and the second choke winding and the second coupling winding have an identical number of turns and are wound in the same direction; and
wherein the third coupling winding is electrically isolated from the third choke winding, and the third choke winding and the third coupling winding have an identical number of turns and are wound in the same direction.

19. The common mode transformer of claim 17 , wherein
the first choke winding and the first coupling winding are both wound around a first portion of the toroidal ferrite core;
the second choke winding and the second coupling winding are both wound around a second portion of the toroidal fer

Assignees

• Hubbell Inc

Inventors

• Pagenkopf Kenneth Edward

Classifications

• H01F27/28

  Coils; Windings; Conductive connections · CPC title

• H01F27/24

  Magnetic cores · CPC title

• H02M1/126

  using passive filters · CPC title

• H02P27/16 Primary

  using AC to AC converters without intermediate conversion to DC (H02P27/05 takes precedence) · CPC title

• H01F27/255

  made from particles (H01F27/26 takes precedence) · CPC title