Maximizing Power in a Photovoltaic Distributed Power System

• US 20130193765A1
• Filed: 01/30/2013
• Published: 08/01/2013
• Est. Priority Date: 01/30/2012
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Yoscovich, Ilan
• Granted Patent: US 9,812,984 B2
• Time in Patent Office: Days
• US Class Current: 307/75
• CPC Class Codes: H02J 2300/10 The dispersed energy generation being of fossil origin, e.g. diesel generators
• 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: H02M 7/42 Conversion of dc power input into ac power output without possibility of reversal
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A power harvesting system including multiple parallel-connected photovoltaic strings, each photovoltaic string includes a series-connection of photovoltaic panels. Multiple voltage-compensation circuits may be connected in series respectively with the photovoltaic strings. The voltage-compensation circuits may be configured to provide respective compensation voltages to the photovoltaic strings to maximize power harvested from the photovoltaic strings. The voltage-compensation circuits may be include respective inputs which may be connected to a source of power and respective outputs which may be connected in series with the photovoltaic strings.

Claims

1. A system comprising:

a plurality of parallel-connected compensated photovoltaic strings, each compensated photovoltaic string including;

a photovoltaic string having a series-connection of photovoltaic cells; and

a voltage-compensation circuit having a voltage output connected in series with said photovoltaic string, wherein said voltage-compensation circuit includes an input connected to a source of power separate from power provided by the photovoltaic string, wherein the voltage-compensation circuit is configured to provide at the voltage output an adjustable compensation voltage in series with a voltage generated by said photovoltaic string such that a total voltage of the compensated photovoltaic string maintains a predetermined value.

3. The system of claim 1, wherein each of said voltage-compensation circuits include one of:

an alternating current (AC) to direct current (DC) converter, wherein the AC to DC converter includes an input connected to said source of power, and wherein the AC to DC converter includes an output configured to provide the adjustable compensation voltage; and

a DC-to-DC converter, wherein the DC to DC converter includes an input connected to said source of power, and wherein the DC to DC converter includes an output configured to provide the adjustable compensation voltage.

4. The system of claim 1, wherein said source of power is provided by an AC power grid.

10. The system of claim 1, wherein each compensated photovoltaic string further comprises:

adapted to measure at least one circuit parameter of said photovoltaic string, wherein said voltage-compensation circuit is adapted to adjust said adjustable compensation voltage based on said at least one measured circuit parameter.

11. The system of claim 10, wherein said at least one measured circuit parameter includes a current flowing in said photovoltaic string.

12. The system of claim 10, wherein said at least one measured circuit parameter includes a voltage across said photovoltaic string.

26. The system of claim 1, wherein each voltage compensation circuit provides its adjustable compensation voltage so as to maximize power harvested from the photovoltaic string connected to the voltage compensation circuit.

27. The system of claim 1, wherein each of the voltage compensation circuits is connected to the same source of power.

28. The system of claim 1, wherein the predetermined value for each of the compensated photovoltaic strings is the same.

29. The system of claim 28, further comprising:

a power converter having an input attached to an output of the plurality of parallel-connected compensated strings and having an output configured to provide the source of power to each of the voltage compensation circuits.

2. (canceled)

5-9. -9. (canceled)

13. A system comprising:

a photovoltaic string including a series connection of photovoltaic cells; and

a voltage-compensation circuit having a voltage output connected in series with said photovoltaic string to form a compensated photovoltaic string, wherein said voltage-compensation circuit includes an input connected to a source of power separate from power provided by the photovoltaic cells within the photovoltaic string, wherein the voltage-compensation circuit is configured to provide at the voltage output au adjustable compensation voltage in series with a voltage generated by the photovoltaic string such that a total voltage of the compensated photovoltaic string maintains a predetermined value.

15. The system of claim 13, wherein said voltage-compensation circuit includes a direct current (DC-to-DC converter having:

a direct current source power input connected to said source of power; and

a direct current output configured to provide the adjustable compensation voltage.

16. The system of claim 13, wherein said voltage-compensation circuit includes:

an alternating current-to-direct current converter having;

an alternating current source input connected to said source of power; and

a direct current output configured to provide the adjustable compensation voltage.

30. The system of claim 13, wherein the voltage compensation circuit provides the adjustable compensation voltage so as to maximize power harvested from the photovoltaic string.

31. The system of claim 13, further comprising:

a sensor operatively connected to said voltage compensation circuit, wherein said sensor is adapted to measure at least one circuit parameter of said photovoltaic string;

wherein said voltage-compensation circuit is adapted to adjust said adjustable compensation voltage based on said at least one measured circuit parameter.

32. The system of claim 31, wherein said at least one measured circuit parameter includes one of a current flowing in said photovoltaic string and a voltage across said photovoltaic string.

14. (canceled)

17. (canceled)

18. A method comprising:

monitoring a circuit parameter within a photovoltaic string;

receiving with a voltage-compensation circuit a source of power separate from power provided by photovoltaic cells within the photovoltaic string;

generating from the source of power, with the voltage-compensation circuit, a compensation voltage based on said monitored circuit parameter; and

adding serially said compensation voltage with a photovoltaic voltage generated by said photovoltaic string such that a total voltage of the compensation voltage and the photovoltaic string voltage maintains a predetermined value.

21. The method of claim 18, wherein said circuit parameter includes one of a current produced by said photovoltaic string, a voltage across said photovoltaic string, and power produced by said photovoltaic string.

24. The method of claim 18, further comprising:

adjusting the compensation voltage such that power harvested from said photovoltaic string is maximized.

25. The method of claim 18, further comprising:

generating the compensation voltage from outputs of a direct current (DC) to DC converter receiving the source of power at inputs of the DC to DC converter.

19-20. -20. (canceled)

22-23. -23. (canceled)