Distributed power harvesting systems using DC power sources

• US 10,447,150 B2
• Filed: 07/05/2017
• Issued: 10/15/2019
• 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): Kaplan, Hal
• Application Number:
  US15/641,553
• Publication Number:
  US 20170373590A1
• Time in Patent Office: 832 Days
• Field of Search: 307117
• CPC Class Codes: G05F 5/00 Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• 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 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• 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 7/35 with light sensitive cells
• CPC Class Codes: H02M 3/04 by static converters
• CPC Class Codes: H02M 7/44 by static converters
• 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 method for maintaining reliability of a distributed power system including a power converter having input terminals and output terminals. Input power is received at the input terminals. The input power is converted to an output power at the output terminals. A temperature is measured in or in the environment of the power converter. The power conversion of the input power to the output power may be controlled to maximize the input power by setting at the input terminals the input voltage or the input current according to predetermined criteria. One of the predetermined criteria is configured to reduce the input power based on the temperature signal responsive to the temperature. The adjustment of input power reduces the input voltage and/or input current thereby lowering the temperature of the power converter.

Claims

1. A method comprising:

determining, by a controller, a maximum power point of a power output of a string of solar cells; and

based on a temperature signal received from a temperature sensor, causing a power converter coupled to the string of solar cells to reduce the power output of the string of solar cells to less than a maximum power associated with the maximum power point.

2. The method of claim 1, wherein the temperature signal indicates a temperature of the power converter.

3. The method of claim 1, wherein the temperature signal indicates a temperature of the string of solar cells.

4. The method of claim 1, wherein causing the power converter to reduce the power output comprises fixing the power output to a selected voltage or current.

5. The method of claim 1, wherein causing the power converter to reduce the power output comprises adjusting a duty cycle of power input to the power converter.

6. The method of claim 5, wherein adjusting the duty cycle further comprises:

responsive to detecting that a voltage of the power output increases, reducing the duty cycle; and

responsive to detecting that the voltage of the power output decreases, increasing the duty cycle.

7. An apparatus comprising:

a string of solar cells;

a temperature sensor;

a power converter coupled to the string of solar cells; and

a controller configured to;

determine a maximum power point of a power output of the string of solar cells; and

cause the power converter to reduce, based on a temperature signal received from the temperature sensor, the power output of the string of solar cells from a maximum power associated with the maximum power point.

8. The apparatus of claim 7, further comprising:

a second string of solar cells;

a second power converter coupled to the second string of solar cells; and

a second controller configured to;

determine a second maximum power point of a second power output of the second string of solar cells; and

cause the second power converter to reduce, based on one or more of the temperature signal and a second temperature signal received from a second temperature sensor, the second power output of the second string of solar cells to less than a second maximum power associated with the second maximum power point.

9. The apparatus of claim 7, wherein the apparatus is a solar panel comprising integrated circuitry.

10. The apparatus of claim 7, wherein the temperature signal indicates a temperature of the power converter.

11. The apparatus of claim 10, wherein the temperature sensor is integrated with the power converter.

12. The apparatus of claim 7, wherein the temperature signal indicates a temperature of the string of solar cells.

13. The apparatus of claim 12, wherein the temperature sensor connects to an input of the controller.

14. The apparatus of claim 7, wherein the controller is configured to cause the power converter to reduce the power output by fixing the power output to a selected voltage or current.

15. The apparatus of claim 7, wherein the controller is configured to cause the power converter to reduce the power output by adjusting a duty cycle of power input to the power converter.

16. The apparatus of claim 15, wherein the controller is configured to adjust the duty cycle by:

responsive to detecting that a voltage of the power output increases, reducing the duty cycle; and

responsive to detecting that the voltage of the power output decreases, increasing the duty cycle.

17. A system comprising:

a solar panel comprising a first string of solar cells;

a first temperature sensor;

a first power converter coupled to the first string of solar cells; and

a first controller configured to;

determine a maximum power point of a power output of the first string of solar cells; and

cause the first power converter to reduce, based on a temperature signal received from the first temperature sensor, the power output of the first string of solar cells to below a maximum power associated with the maximum power point.

18. The system of claim 17, wherein the solar panel further comprises a second string of solar cells, the system further comprising:

a second power converter coupled to the second string of solar cells; and

a second controller configured to;

determine a second maximum power point of a second power output of the second string of solar cells; and

cause the second power converter to reduce, based on one of the temperature signal and a second temperature signal received from a second temperature sensor, the second power output of the second string of solar cells to below a second maximum power associated with the second maximum power point.

19. The system of claim 17, wherein the temperature signal indicates a temperature of the first power converter.

20. The system of claim 17, wherein the temperature signal indicates a temperature of the first string of solar cells.