DISTRIBUTED POWER HARVESTING SYSTEMS USING DC POWER SOURCES

• US 20110273015A1
• Filed: 07/14/2011
• Published: 11/10/2011
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Galin, Yoav, Fishelov, Amir, Adest, Meir, Sella, Guy, Handelsman, Lior, Gazit, Meir
• Granted Patent: US 9,130,401 B2
• Time in Patent Office: Days
• US Class Current: 307/43
• 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 3/381 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: H02S 40/34 comprising specially adapted electrical connection means to be structurally associated with the PV module, e.g. junction boxes
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A photovoltaic panel with multiple photovoltaic sub-strings including serially-connected photovoltaic cells and having direct current (DC) outputs adapted for interconnection in parallel into a parallel-connected DC power source. A direct current (DC) power converter including input terminals and output terminals is adapted for coupling to the parallel-connected DC power source and for converting an input power received at the input terminals to an output power at the output terminals. The direct current (DC) power converter optionally has a control loop configured to set the input power received at the input terminals according to a previously determined criterion. The control loop may be adapted to receive a feedback signal from the input terminals for maximizing the input power. A bypass diode is typically connected in shunt across the input terminals of the converter. The bypass diode functions by passing current during a failure of any of the sub-strings and/or a partial shading of the sub-strings. The bypass diode may be a single bypass diode connected across the parallel-connected DC power source. The DC power converter may convert the input power at high current to the output power at a lower current. The output terminals may be connectible with wire cables to a load, and the DC power converter is configured to reduce energy loss through the wire cables to the load.

Claims

1. A photovoltaic panel comprising:

a plurality of photovoltaic sub-strings including serially-connected photovoltaic cells, wherein the sub-strings have direct current (DC) outputs adapted for interconnection in parallel into a parallel-connected DC power source; and

a direct current (DC) power converter including input terminals adapted for coupling to said parallel-connected DC power source and for converting an input power received at said input terminals to an output power at output terminals.

2. The photovoltaic panel of claim 1, wherein said direct current (DC) power converter has a control loop configured to set the input power received at said input terminals according to a previously determined criterion.

3. The photovoltaic panel of claim 1, wherein said direct current (DC) power converter has a control loop adapted to maximize the input power by setting input voltage.

4. The photovoltaic panel of claim 1 further comprising:

a bypass diode connected in shunt across said input terminals of said converter,

5. The photovoltaic panel of claim 4, wherein said bypass diode functions by passing current during at least one condition selected from the group consisting of:

a failure of any of said sub-strings and a partial shading of said sub-strings.

6. The photovoltaic panel of claim 4, wherein said bypass diode is a single bypass diode connected across the parallel-connected DC power source output.

7. The photovoltaic panel of claim 1, wherein said DC power converter converts said input power at high current to said output power at a lower current.

8. The photovoltaic panel of claim 3, wherein said output terminals are connectible with wire cables to a load, whereby said DC power converter is configured to reduce energy loss through said wire cables to said load.

9. A distributed power harvesting system comprising:

a photovoltaic panel having a plurality of sub-strings including serially-connected photovoltaic cells, wherein said sub-strings are connectible in parallel to provide a parallel-connected DC power source; and

a power converter with input terminals adapted for attaching to said parallel-connected DC power source output.

10. The distributed power harvesting system according to claim 9, further comprising:

a bypass diode connected across said parallel-connected DC power source.

11. The distributed power harvesting system according to claim 9, further comprising:

a load connectible to the output terminals.

12. The distributed power harvesting system according to claim 9, wherein said power converter includes a circuit loop configured to set input power received at said input terminals according to a previously determined criterion

13. The distributed power harvesting system according to claim 12 wherein said previously determined criterion is a maximum input power.

14. A method for power harvesting in a system including a photovoltaic panel with a plurality of sub-strings including serially-connected photovoltaic cells, a power converter with input terminals and output terminals, the method comprising:

connecting the sub-strings in parallel to provide a parallel-connected DC power source;

attaching the input terminals of the converter to the parallel-connected DC power source.

15. The method according to claim 14, further comprising:

attaching a single bypass diode across said parallel-connected DC power source output.

16. The method according to claim 14, further comprising:

converting power by the power converter from the input terminals to the output terminals;

during said converting, setting the input power received at the input terminals according to a previously determined criterion.

17. The method according to claim 14, further comprising:

connecting the output terminals to a load;

converting power by the power converter from the input terminals to the output terminals;

while said converting power, reducing the current output from the output terminals, thereby reducing energy losses.