Solar systems that include one or more shade-tolerant wiring schemes

Abstract

The present invention provides shade tolerant wiring solutions for solar systems. Elements are grouped and wired in parallel within a group such that the total current of a group is substantially the same among multiple groups. Such a wiring scheme can be applied to solar targets (e.g., solar cells), solar , and solar modules.

Description

PRIORITY CLAIM[0001]The present non-provisional patent Application claims priority under 35 U.S.C. §119(e) from United States Provisional patent application having Ser. No. 61 / 128,009, filed on May 16, 2008, by Hines et al. and titled CONCENTRATING PHOTOVOLTAIC SOLAR PANEL, from United States Provisional patent application having Ser. No. 61 / 131,178, filed on Jun. 6, 2008, by Hines et al. and titled CONCENTRATING PHOTOVOLTAIC SOLAR PANEL, and from United States Provisional patent application having Ser. No. 61 / 209,526, filed on Mar. 6, 2009, by Baker et al. and titled SOLAR SYSTEMS THAT INCLUDE ONE OR MORE SHADE-TOLERANT WIRING SCHEMES, wherein the respective entireties of said provisional patent applications are incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]The present invention was made with Government support under Cooperative Agreement No. DE-FC36-07G017044 awarded by the U.S. Department of Energy. The Government has certai...

AI Technical Summary

Benefits of technology

[0022]For example, the present invention can provide a photovoltaic solar module and / or system that can exhibit improved shadow tolerance relative to a module or system using traditional bypassing techniques, by providing one or more wiring schemes that allow partially shadowed solar cells to contribute output power to a series string. Advantageously, using such wiring schemes can help avoid the activation of bypass diodes with their concomitant power consumption.

[0026]The present invention also teaches that patterns of light and shadow on a solar panel tend to be highly correlated and systematic, so that much of the benefit of an arbitrary-wiring central switchboard as discussed above in connection with FIG. 10 can be achieved with a much simpler static wiring approach that takes advantage of the systematic nature of the shadows that fall on the solar panel. The systematic nature of shadowing can arise because the primary shading source tends to be self-shading by adjacent solar modules that are either arranged at a fixed tilt or on tracking systems. For rooftop installations, other sources of shadowing include objects such as parapet walls, airconditioner units, and elevator shafts that tend to cast shadows having relatively simple geometry.

[0027]In particular, as shown in FIGS. 11A and 11B, a typical shadow 60 is not random but rather has a relatively simple structure (such as straight lines and a simple polygon), and it may be desirable to partition the aperture 62 of a solar submodule into sub-apertures 64 and then wire the solar cells 72 corresponding to some of the sub-apertures 64 in parallel into one group 66, while wiring the solar cells 74 corresponding to the other subapertures 64 into one or more other groups 68, and then producing a desired output voltage by wiring the groups into a series circuit 70. Providing a multiplicity of parallel-wired groups 66 or 68 may allow the parallel-wired groups to receive similar amounts of total sunlight. By providing similar amounts of total sunlight to the multiplicity of parallel-wired groups, the groups then may be wired together in series without substantial loss of output power and without producing voltages which will forward bias shadowed solar cells or activate bypass diodes.

Problems solved by technology

However, when solar panels are not installed flat, they tend to cast shadows.

Traditionally, solar panels are not especially tolerant of shadows.

While such spacing helps each solar panel to produce a high amount of energy, it does not make efficient use of space, whether it be land as shown in the FIG. 1 and 2, or rooftop space in the case of a rooftop installation.

Conventional photovoltaic solar panels tend to lack shadow tolerance because of the properties of the individual solar cells and because of the way photovoltaic systems are typically wired together.

In fact, further exacerbating this problem, general practice is not to include a bypass diode 46 for every individual solar cells 30 and 47, but to include a single bypass diode around a group of solar cells, or even around an entire solar submodule or module, thus regrettably leading to an even greater loss of potential power by virtue of bypassing completely illuminated cells in addition to a partially shaded cell or cells.

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