System and method for converting solar energy to electricity

#The disclosed technique relates to energy conversion in general, and to methods and systems for increasing the efficiency of photovoltaic cells, in particular.

#The solar radiation which reaches the Earth, is used to produce electrical power. Methods and systems of converting the solar radiation to electrical power are known in the art, such as heliothermal, heliochemical, helioelectrical, and the like.

#In heliothermal processes the solar radiation is absorbed and converted to heat, which can be used for many purposes, such as house heating by warm air or water, cooling by absorption refrigeration, cooking, generating electricity by vapor cycles, and the like. In heliochemical processes the shorter wavelengths can cause chemical reactions, sustain growth of plants and animals, convert carbon dioxide to oxygen by photosynthesis, cause degradation of fabrics, plastics and paint, and the like. In helioelectrical processes part of the solar energy can be converted directly into electricity by photovoltaic cells.

#The disclosed technique will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

#FIG. 1A is a schematic illustration of a plurality of cells on a cell array, constructed and operative in accordance with an embodiment of the disclosed technique;

#FIG. 1B is a schematic illustration of a circuit in which the cells of FIG. 1A are coupled with a load;

#The disclosed technique overcomes the disadvantages of the prior art by coupling the photovoltaic cells, according to the flux of a concentrated light which illuminates each cell. The cells which receive light of the same flux, are grouped together and all the cells in a group produce the same current. Thus, the output current of a group of cells is proportional to the flux of the concentrated light which illuminates this group, and this output current is not limited by a low-current-producing cell, which would otherwise be coupled with this group.

#The term “cell” herein below, refers to a single photovoltaic cell. The term “group” refers to a plurality of cells, having the same flux, which are coupled together. The term “sub-group” herein below, refers to a group of cells which all receive a concentrated light having the same flux, wherein not all of these cells are necessarily coupled together. A group can include a plurality of sub-groups, which are coupled together. The term “low-current-producing cell” herein below, refers to a cell whose output current falls due to reduction in the flux of light reaching the cell, or due to a malfunction in the cell. A low-current-producing cell can produce a lower current, when there is a fall in the flux of light which reaches the cell, when the cell malfunctions.

#The term “low-current-producing group” herein below, refers to a group which includes one or more low-current-producing cells or a dead cell whose output power is zero. The term “light” herein below, refers to a concentrated light which is focused on the photovoltaic cell array, by a focusing element, such as lens, lens assembly, one mirror, a plurality of mirrors, light guide, and the like. The mirror can be concave (known in the art as “dish”), in which case it is in form of a paraboloid, hyperboloid, catenary of revolution, and the like. The term “iso-flux regions” herein below, refers to different regions of a cell array where the light falling thereon, is of substantially the same flux.