Auto adjusting balancer apparatus

• US 10,439,414 B2
• Filed: 04/23/2018
• Issued: 10/08/2019
• Est. Priority Date: 03/23/2017
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Inventors: Oughton, Jr., George William
• Primary Examiner(s): Moody, Kyle J
• Application Number:
  US15/959,659
• Publication Number:
  US 20180278074A1
• Time in Patent Office: 533 Days
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H02M 7/4833 Capacitor voltage balancing

Abstract

An apparatus includes a string of serially-connected energy storage devices, a string of serially-connected windings on at least one core and having a first medial node coupled to a first medial node of the string of serially-connected energy storage devices, and first and second switches configured to connect first and second end nodes of the string of serially-connected storage devices to respective first and second end nodes of the string of serially-connected energy storage devices. A control circuit is configured to operate the first and second switches at the same duty cycle.

Claims

1. An apparatus comprising:

first, second, third and fourth serially connected windings;

a first switch configured to connect a first tap of the first winding to a first terminal of a first energy storage device;

a second switch configured to connect a second tap of the first winding and a first tap of the second winding to a second terminal of the first energy storage device and the first terminal of a second energy storage device, the second tap of the second winding and a first tap of the third winding connected to a second terminal of the second energy storage device and a first terminal of a third energy storage device;

a third switch configured to connect a second tap of the third winding and a first tap of the fourth winding to a second terminal of the third energy storage device and a first terminal of a fourth energy storage device;

a fourth switch configured to connect a second tap of the fourth winding to a second terminal of the fourth energy storage device; and

a control circuit configured to operate the first, second, third and fourth, switches at a same duty cycle.

2. The apparatus of claim 1 wherein the first and second windings are magnetically coupled to one another and wherein the third and fourth windings are magnetically coupled to one another.

3. The apparatus of claim 2, wherein the first and second windings are wound on a first core and wherein the third and fourth windings are wound on a second core.

4. The apparatus of claim 2, wherein a turns ratio of the first winding to the second winding is 1:

1 and wherein a turns ratio of the third winding to the fourth winding is 1;

1.

5. The apparatus of claim 1, wherein the first, second, third and fourth windings are magnetically coupled to one another.

6. The apparatus of claim 5, wherein the first, second, third and fourth windings are wound on a common core.

7. The apparatus of claim 5, wherein a turns ratio of the first, second, third and fourth windings to one another is 1:

1.

8. The apparatus of claim 1, wherein the same duty cycle is less than 50%.

9. The apparatus of claim 8, wherein the same duty cycle is greater than 40%.

10. The apparatus of claim 1, further comprising:

a first diode connected between the first terminal of the first energy storage device and the second terminal of the fourth winding; and

a second diode connected between the second terminal of the fourth enemy storage device and the first terminal of the first winding.

11. The apparatus of claim 1, wherein the first, second, third and fourth switches are bidirectional.

12. The apparatus of claim 11, wherein the first and third switches each comprise an insulated gate bipolar transistor (IGBT) and a diode coupled in parallel with the IGBT.

13. The apparatus of claim 1, wherein the second and fourth switches each comprise two IGBTs coupled in series and respective diodes coupled in parallel with the IGBTs.

14. The apparatus of claim 1, wherein the first, second, third and fourth energy storage devices comprise capacitors or batteries.

15. The apparatus of claim 1, further comprising a multilevel inverter circuit coupled to the terminals of the first, second, third and fourth energy storage devices.

16. An apparatus comprising:

a string of serially-connected energy storage devices;

a string of serially-connected windings on at least one core and having a first medial node coupled to a first medial node of the string of serially-connected energy storage devices; and

first and second switches, configured to connect first and second end nodes of the string of serially-connected windings to respective first and second end nodes of the string of serially-connected energy storage devices; and

a control circuit configured to alternately open and close the first and second switches at a same duty cycle while the first medial node of the string of serially-connected windings and the first medial node of the string of serially-connected energy storage devices are continuously connected to one another,

wherein the string of serially-connected energy storm devices comprises at least four serially-connected energy storage devices;

wherein the string of serially-connected windings comprises at least four serially-connected windings; and

third and fourth switches, respective ones of which are configured to connect respective second and third medial nodes of the string of serially-connected windings to respective second and third medial nodes of the string of serially-connected energy storage devices.

17. The apparatus of claim 16, wherein the at least four serially-connected windings are wound on a single core.

18. The apparatus of claim 16, wherein the string of serially-connected energy storage devices comprises capacitors or batteries.

19. The apparatus of claim 16, further comprising a multi-level inverter coupled to the string of serially-connected energy storage devices.