Distributed power system using direct current power sources

• US 9,853,490 B2
• Filed: 04/27/2016
• Issued: 12/26/2017
• Est. Priority Date: 12/06/2006
• 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:
  US15/139,745
• Publication Number:
  US 20160241079A1
• Time in Patent Office: 608 Days
• Field of Search: 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 3/381 Dispersed generators
• 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 system comprising:

a plurality of power converters, each power converter coupled to a corresponding DC power source of a plurality of DC power sources, wherein each power converter comprises;

control circuitry configured to provide a feedback signal to the power converter from a connection between the power converter and the corresponding DC power source coupled to the power converter; and

a power conversion portion configured to charge or discharge the corresponding DC power source coupled to the power converter,

wherein each power converter of the plurality of power converters is connected in series to at least one other power converter of the plurality of power converters.

2. The system of claim 1, wherein the control circuitry in each power converter of the plurality of power converters is configured to set a voltage between or current through terminals of the power converter.

3. The system of claim 1, wherein the control circuitry in each power converter of the plurality of power converters is configured to lock an input voltage and current from the corresponding DC power source coupled to that power converter to an optimal power point.

4. The system of claim 1, wherein each power converter of the plurality of power converters is configured to function as one or more of a current source, a voltage regulator, or a trickle charge source.

5. The system of claim 1, wherein a first DC power source of the plurality of DC power sources comprises a DC battery.

6. The system of claim 1, wherein a first DC power source of the plurality of DC power sources comprises a solar panel.

7. The system of claim 1, wherein a first power converter of the plurality of power converters is coupled to a first DC power source, the first DC power source comprising a plurality of solar cells connected in series, or a plurality of solar cells connected in parallel, or a plurality of solar cells connected in both series and parallel.

8. The system of claim 1, wherein the plurality of power converters are configured to form a serial string of power converters, and wherein the system further comprises:

a power controller coupled to the serial string of power converters, the power controller configured to maintain current through or voltage across the serial string of power converters at a regulated value.

9. The system of claim 8, wherein the power controller comprises one or more of a bi-directional DC/AC inverter, a bi-directional DC/DC converter, a charging regulator, or a load controller.

10. The system of claim 9, further comprising a shunt regulator coupled to the serial string of power converters and to the power controller.

11. A system comprising:

a first plurality of DC power sources;

a first plurality of power converters, wherein each power converter of the first plurality of power converters is coupled to a corresponding DC power source of the first plurality of DC power sources, wherein each power converter of the first plurality of power converters comprises control circuitry and a power conversion portion, and wherein each power converter of the first plurality of power converters is serially connected to at least one other power converter of the first plurality of power converters, thereby forming a first serial string;

a second plurality of DC power sources; and

a second plurality of power converters, wherein each of second plurality of power converters is coupled to a corresponding DC power source of the second plurality of DC power sources, wherein each power converter of the second plurality of power converters comprises control circuitry and a power conversion portion, and wherein each power converter of the second plurality of power converters is serially connected to at least one other power converter of the second plurality of power converters, thereby forming a second serial string,

wherein the first serial string and the second serial string are connected in parallel to form parallel-connected strings.

12. The system of claim 11, wherein the control circuitry in each power converter of the first plurality of power converters and each power converter of the second plurality of power converters is configured to provide a feedback signal to the power converter from a connection between the power converter and the corresponding DC power source coupled to the power converter.

13. The system of claim 11, wherein the first plurality of DC power sources comprise one or more batteries.

14. The system of claim 13, wherein the second plurality of DC power sources comprise one or more photovoltaic panels.

15. The system of claim 11, further comprising:

a power controller coupled in parallel to the parallel-connected strings, the power controller configured to maintain current through or voltage across the parallel-connected strings at a first value.

16. The system of claim 15, wherein the power controller is further configured to control a direction of the current and to charge the first plurality of DC power sources from the second plurality of DC power sources.

17. The system of claim 16, wherein the power controller is further configured to:

determine that an amount of power received from the second plurality of DC power sources is insufficient to charge all of the first plurality of DC power sources; and

based on the determination and when charging the first plurality of DC power sources, turn off one or more of the first plurality of power converters, while leaving on the remaining power converters in the first plurality of power converters.

18. The system of claim 16, wherein each power converter of the first plurality of power converters is configured to:

during the charging of the first plurality of DC power sources by the power controller, determine whether the corresponding DC power source coupled to that power converter is full; and

based on a determination that the corresponding DC power source is full, enter a bypass mode in which power is not taken from the power controller by that power converter.

19. The system of claim 16, wherein the first plurality of power converters are configured to draw different amounts of power from the power controller based on power needs of the plurality of DC power sources coupled to the first plurality of power converters.

20. A method, comprising:

coupling a plurality of DC power sources respectively to a plurality of power converters, wherein each power converter of the plurality of power converters comprises;

a control circuit configured to provide a feedback signal to the power converter from a connection between the power converter and the DC power source coupled to that power converter; and

a power conversion portion configured to convert power to discharge or charge the DC power source coupled to that power converter;

coupling the plurality of power converters together in a serial connection to form a serial string of power converters; and

coupling the serial string of power converters to a power controller configured to maintain current through or voltage across the serial string of power converters at a set value.