Distributed power system using direct current power sources

• US 8,618,692 B2
• Filed: 10/25/2010
• Issued: 12/31/2013
• Est. Priority Date: 12/04/2007
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Adest, Meir, Handelsman, Lior, Galin, Yoav, Fishelov, Amir, Sella, Guy, Binder, Yaron
• Primary Examiner(s): Deberadinis, Robert L.
• Application Number:
  US12/911,153
• Publication Number:
  US 20110084553A1
• Time in Patent Office: 1,163 Days
• Field of Search: 307/58
• US Class Current: 307/58
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A distributed power system including multiple (DC) batteries each DC battery with positive and negative poles. Multiple power converters are coupled respectively to the DC batteries. Each power converter includes a first terminal, a second terminal, a third terminal and a fourth terminal. The first terminal is adapted for coupling to the positive pole. The second terminal is adapted for coupling to the negative pole. The power converter includes: (i) a control loop adapted for setting the voltage between or current through the first and second terminals, and (ii) a power conversion portion adapted to selectively either: convert power from said first and second terminals to said third and fourth terminals to discharge the battery connected thereto, or to convert power from the third and fourth terminals to the first and second terminals to charge the battery connected thereto. Each of the power converters is adapted for serial connection to at least one other power converter by connecting respectively the third and fourth terminals, thereby forming a serial string. A power controller is adapted for coupling to the serial string. The power controller includes a control part adapted to maintain current through or voltage across the serial string at a predetermined value.

Claims

1. A distributed power system comprising:

a plurality of DC power sources, each DC power source with positive and negative poles;

a plurality of power converters coupled respectively to the DC power sources, each power converter including a first terminal, a second terminal, a third terminal and a fourth terminal, wherein said first terminal is adapted for coupling to said positive pole and said second terminal is adapted for coupling to said negative pole;

wherein each said power converter includes;

(i) a control loop adapted for setting the voltage between or current through said first and second terminals, and

(ii) a power conversion portion adapted to perform at least one of;

converting power from said first and second terminals to said third and fourth terminals to discharge said power source connected thereto, or converting power from said third and fourth terminals to said first and second terminals to charge said power source connected thereto;

wherein each of said power converters is adapted for serial connection to at least one other power converter by connecting respectively said third and fourth terminals, thereby forming a serial string; and

a power controller adapted for coupling to said serial string, the power controller including a control part adapted to maintain current through or voltage across said serial string at a predetermined value.

2. The distributed power system of claim 1, wherein the control part maintains voltage across said serial string at a predetermined value.

3. The distributed power system of claim 1, wherein the control part maintains current through said serial string at a predetermined value.

4. The distributed power system of claim 1, wherein the power controller includes a bi-directional DC/AC inverter.

5. The distributed power system of claim 1, wherein the power controller includes a bi-directional DC/DC converter.

6. The distributed power system of claim 1, wherein said power converters have a function selected from the group consisting of:

current source, voltage regulation or trickle charge.

7. The distributed power system according to claim 1, wherein the DC power sources comprise DC batteries.

8. The distributed power system according to claim 7, further comprising:

a plurality of photovoltaic panels;

a plurality of DC-to-DC converters, each of the DC-to-DC converters including;

one or more input terminals coupled to one or more of the photovoltaic panels;

one or more output terminals coupled in series to one or more of the other DC-to-DC converters, thereby forming a second serial string;

a control loop adapted to set the voltage and current at the input terminals of the DC-to-DC converter according to predetermined criteria; and

,

a power conversion portion adapted to convert the power received at the input terminals to an output power at the output terminals;

wherein said serial string and said second serial string are connectible in parallel to form parallel-connected strings.

9. The distributed power system according to claim 8, wherein the power controller is further adapted for coupling in parallel to said parallel-connected strings, wherein the control part of the power controller is further adapted to maintain current through or voltage across said parallel connected strings at a predetermined value.

10. The distributed power system according to claim 8, wherein said power controller is selectably either off-grid or connected to grid.

11. The distributed power system according to claim 8, wherein said photovoltaic panels provide electrical power for charging said DC power sources.

12. The distributed power system according to claim 1, wherein the DC power sources comprise solar panels.

13. A distributed power system comprising:

a plurality of DC power sources, each DC power source with positive and negative poles;

a plurality of power converters coupled respectively to the DC power sources, each power converter including a first terminal, a second terminal, a third terminal and a fourth terminal, wherein said first terminal is adapted for coupling to said positive pole and said second terminal is adapted for coupling to said negative pole;

wherein each said power converter includes;

(i) a first control loop configured to set either current through or voltage between said first and second terminals,

(ii) a second control loop configured set either current through or voltage between said third and fourth terminals; and

(iii) a power conversion portion adapted to perform at least one of;

converting power from said first and second terminals to said third and fourth terminals to discharge said power source connected thereto, or converting power from said third and fourth terminals to said first and second terminals to charge said power source connected thereto;

wherein each of said power converters is adapted for serial connection to at least one other power converter by connecting respectively said third and fourth terminals, thereby forming a serial string.

14. The distributed power system according to claim 13, wherein the DC power sources comprise DC batteries.

15. The distributed power system according to claim 14, further comprising:

a plurality of photovoltaic panels;

a plurality of DC-to-DC converters, each of the DC-to-DC converters including;

one or more input terminals coupled to one or more of the DC photovoltaic panels;

one or more output terminals coupled in series to one or more of the other DC-to-DC converters, thereby forming a second serial string;

a control loop adapted to set the voltage and current at the input terminals of the DC-to-DC converter according to predetermined criteria; and

,

a power conversion portion adapted to convert the power received at the input terminals to an output power at the output terminals;

wherein said serial string and said second serial string are connectible in parallel.

16. The distributed power system according to claim 15, further comprising a power controller, wherein said power controller is selectably either off-grid or connected to grid.

17. The distributed power system according to claim 15, wherein said photovoltaic panels provide electrical power for charging said power sources.

18. The distributed power system according to claim 15, further comprising a communications interface between said power converters and a power controller for controlling charging and discharging of said power sources.

19. The distributed power system according to claim 13, wherein the DC power sources comprise solar panels.

20. A method, comprising:

coupling a plurality of DC power sources to a plurality of power converters, wherein each said DC power source includes a positive and a negative pole, wherein each said power converter includes a first terminal, a second terminal, a third terminal and a fourth terminal, wherein said first terminal is adapted for coupling to said positive pole and said second terminal is adapted for coupling to said negative pole, and wherein each said power converter further includes;

(i) a control loop adapted for setting the voltage between or current through said first and second terminals, and

(ii) a power conversion portion adapted to perform at least one of;

converting power from said first and second terminals to said third and fourth terminals to discharge said power source connected thereto, or converting power from said third and fourth terminals to said first and second terminals to charge said power source connected thereto;

connecting in serial each of said power converters to at least one other power converter by connecting respectively said third and fourth terminals, thereby forming a serial string; and

coupling a power controller to said serial string, the power controller including a control part adapted to maintain current through or voltage across said serial string at a predetermined value.