CPV TRACKING USING PARTIAL CELL VOLTAGES
REFERENCE TO RELATED APPLICATIONS
Reference is made to U.S. Provisional Patent Application Serial No.
61/431,138, filed January 10, 2011 and entitled "CPV TRACKING USING PARTIAL
CELL VOLTAGES", the disclosure of which is hereby incorporated by reference and
priority of which is hereby claimed pursuant to 37 CFR 1.78(a) (4) and (5)(i).
Reference is also made to the following patents and patent applications,
owned by assignee, the disclosures of which are hereby incorporated by reference:
U.S. Published Patent Application Nos.: 2009/0065045, 2010/0252091
and 2011/0061719; and
U.S. Patent Application Serial No.: 12/947,483.
FIELD OF THE INVENTION
The present invention relates to concentrated photovoltaic power
generation.
BACKGROUND OF THE INVENTION
The following patents, patent publications and publications are believed
to represent the current state of the art:
U.S. Patent Nos.: 7,834,303 and 7,884,308; and
U.S. Published Patent Application Nos.: 2008/0087321, 2009/0145480,
2010/0059042 and 2010/0059043.
SUMMARY OF THE INVENTION
The present invention seeks to provide improved systems and methods of
concentrated photovoltaic power generation.
There is thus provided in accordance with a preferred embodiment of the
present invention a solar electricity generator including an array of solar electricity
generating elements, a solar energy concentrating element operative to transmit
concentrated solar radiation from the sun onto the array, voltage measuring functionality
operative to measure at least one of a total row voltage generated by at le st one row of
the electricity generating elements in the array and a total column voltage generated by
at least one column of the electricity generating elements in the array, vertical
positioning functionality operative, in response to ascertaining by the voltage measuring
functionality that a first total row voltage generated by a first multiplicity of the rows is
less than a second total row voltage generated by a second multiplicity of rows, to
generally vertically reposition the solar energy concentrating element thereby to
increase exposure of the first multiplicity of the rows to solar radiation transmitted from
the sun by the solar energy concentrating element, and horizontal positioning
functionality operative, in response to ascertaining by the voltage measuring
functionality that a first total column voltage generated by a first multiplicity of the
columns is less than a second total column voltage generated by a second multiplicity of
columns, to horizontally reposition the solar energy concentrating element thereby to
increase exposure of the first multiplicity of the columns to solar radiation transmitted
from the sun by the solar energy concentrating element.
Preferably, the solar energy concentrating element is a concave reflecting
surface. Alternatively, the solar energy concentrating element is a concentrating lens.
Preferably, the solar electricity generator also includes solar tracking
functionality operative to utilize astronomical information to rotate and position the
energy concentrating element opposite the sun throughout the day. Preferably, the solar
electricity generating elements are serially connected. Preferably, the voltELge measuring
functionality is operative to continuously measure the row and column voltages
throughout the day.
There is also provided in accordance with another preferred embodiment
of the present invention a method for generating solar electricity including transmitting
concentrated solar radiation from the sun onto an array of solar electricity generating
elements, measuring at least one of a total row voltage generated by at least one row of
the electricity generating elements in the array and a total column voltage generated by
at least one column of the electricity generating elements in the array, in response to
ascertaining by the measuring that a first total row voltage generated by a first
multiplicity of the rows is less than a second total row voltage generated by a second
multiplicity of rows, to generally vertically reposition the solar energy concentrating
element thereby to increase exposure of the first multiplicity of the rows to solar
radiation transmitted from the sun by the solar energy concentrating element, and in
response to ascertaining by the measuring that a first total column voltage generated by
a first multiplicity of the columns is less than a second total column voltage generated
by a second multiplicity of columns, to horizontally reposition the solar energy
concentrating element thereby to increase exposure of the first multiplicity of the
columns to solar radiation transmitted from the sun by the solar energy concentrating
element.
Preferably, the measuring includes continuously measuring throughout
the day.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood more fully from the following
detailed description, taken in conjunction with the drawings in which:
Fig. 1 is a simplified pictorial illustration of a solar electricity generator
constructed and operative in accordance with a preferred embodiment of the invention;
Figs. 2A and 2B are simplified pictorial illustrations of steps in the
operation of the solar electricity generator of Fig. 1; and
Figs. 3A and 3B are simplified pictorial illustration of further steps in the
operation of the solar electricity generator of Fig. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference is now made to Fig. 1, which is a simplified pictorial
illustration of a solar electricity generator constructed and operative in accordance with
a preferred embodiment of the invention. The solar electricity generator of Fig. 1
preferably includes an array of solar electricity generating elements, a solar energy
concentrating element operative to transmit concentrated solar radiation from the sun
onto the array, and voltage measuring functionality operative to measure at least one of
a total row voltage generated by at least one row of the electricity generating elements
in the array and a total column voltage generated by at least one column of the
electricity generating elements in the array.
It is a particular feature of the present invention that the solar electricity
generator of Fig. 1 preferably includes vertical positioning functionality operative, in
response to ascertaining by the voltage measuring functionality that a first total row
voltage generated by a first multiplicity of the rows is less than a second total row
voltage generated by a second multiplicity of rows, to generally vertically reposition the
solar energy concentrating element thereby to increase exposure of the first multiplicity
of the rows to solar radiation transmitted from the sun by the solar energy concentrating
element.
Similarly, the solar electricity generator of Fig. 1 also preferably includes
horizontal positioning functionality operative, in response to ascertaining by the voltage
measuring functionality that a first total column voltage generated by a first multiplicity
of the columns is less than a second total column voltage generated by a second
multiplicity of columns, to horizontally reposition the solar energy concentrating
element thereby to increase exposure of the first multiplicity of the columns to solar
radiation transmitted from the sun by the solar energy concentrating element.
As shown in Fig. 1, a solar electricity generator 100 includes a solar
energy concentrating element, such as a concave reflecting surface 102. Alternatively,
the solar energy concentrating element may be, for example, a concentrating lens.
Preferably, a solar tracking system 104 such as a PESOS® SFC 30
Tracking System, commercially available from PAIRAN Elektronik GmbH of
Gottingen, Germany, is provided for rotating and positioning reflecting surface 102
opposite the sun throughout the day. Preferably, tracking system 104 utilizes
astronomical information to position reflecting surface 102 opposite the sun.
An array 110 of solar electricity generating elements is preferably
mounted generally opposite reflecting surface 102, thereby being arranged to absorb
solar radiation reflected thereupon by reflecting surface 102. Preferably, array 110 is
divided into four quadrants of solar electricity generating elements, which quadrants are
designated by reference numerals 112, 114, 116 and 118. Quadrants 112, 114, 116 and
118 are preferably serially connected by connecting elements 122, 124 and 126,
whereby the total voltage generated by array 110 is provided between terminals 128 and
130.
Voltage meter 132 is preferably provided for measuring electric voltage
VI generated by quadrant 112 of solar electricity generating elements between terminal
128 and connecting element 122. Voltage meter 134 is preferably provided for
measuring electric voltage V2 generated by quadrant 114 of solar electricity generating
elements between connecting element 122 and connecting element 124. Voltage meter
136 is preferably provided for measuring electric voltage V3 generated by quadrant 116
of solar electricity generating elements between connecting element 124 and connecting
element 126. Voltage meter 138 is preferably provided for measuring electric voltage
V4 generated by quadrant 118 of solar electricity generating elements between
connecting element 126 and terminal 130.
It is appreciated that voltage meters 132, 134, 136 and 138 preferably
continuously measure voltages VI, V2, V3 and V4 throughout the day.
Reference is now made to Figs. 2A and 2B, which are simplified
pictorial illustrations of steps in the operation of the solar electricity generator of Fig. 1.
As shown in Fig. 2A, solar radiation reflected by reflecting surface 102 is not entirely
aligned with the surface of array 110, and a portion of the solar radiation reflected by
reflecting surface 102 does not impinge on array 110. Furthermore, the misalignment of
the solar radiation reflected by reflecting surface 102 with array 110 causes the
quadrants 112 and 118 to be impinged with less radiation quadrants 114 and 116,
thereby causing the combined generated electric voltages VI and V4 of respective
quadrants 112 and 118 to be lower than the combined generated electric voltages V2
and V3 of respective quadrants 114 and 116.
As mentioned hereinabove, it is a particular feature of the present
invention that solar electricity generator 100 preferably includes horizontal positioning
functionality operative, in response to ascertaining that the combined generated electric
voltages VI and V4 are less than the combined generated electric voltages V2 and V3,
to horizontally reposition reflecting surface 102 opposite the sun and to thereby increase
exposure of quadrants 112 and 118 to solar radiation reflected from the sun by reflecting
surface 102.
It is appreciated that the horizontal positioning functionality is typically
provided in addition to the solar tracking functionality provided by solar tracking
system 104, and may be either integrated within solar tracking system 104 or provided
in addition to solar tracking system 104. However, it is also appreciated that the
horizontal positioning functionality utilizes information provided solely by voltage
meters 132, 134, 136 and 138 and does not require information regarding the relative
position of solar electricity generator 100 and the sun in order to reposition reflecting
surface 102 opposite the sun.
As shown in Fig. 2B, after generally rightward repositioning of reflecting
surface 102 by the horizontal positioning functionality, quadrants 112, 114, 116 and 118
are all generally equally exposed to solar radiation reflected from the sun by reflecting
surface 102, thereby causing subsequent measurements of generated electric voltages
VI, V2, V3 and V4 to be generally equal.
Reference is now made to Figs. 3A and 3B, which are simplified
pictorial illustration of further steps in the operation of the solar electricity generator of
Fig. 1. As shown in Fig. 3A, solar radiation reflected by reflecting surface 102 is not
entirely aligned with the surface of array 110, and a portion of the solar radiation
reflected by reflecting surface 102 does not impinge on array 110. Furthermore, the
misalignment of the solar radiation reflected by reflecting surface 102 with array 110
causes the quadrants 116 and 118 to be impinged with less radiation quadrants 112 and
114, thereby causing the combined generated electric voltages V3 and V4 of respective
quadrants 116 and 118 to be lower than the combined generated electric voltages VI
and V2 of respective quadrants 112 and 114.
As mentioned hereinabove, it is a particular feature of the present
invention that solar electricity generator 100 preferably includes vertical positioning
functionality operative, in response to ascertaining that the combined generated electric
voltages V3 and V4 are less than the combined generated electric voltages VI and V2,
to vertically reposition reflecting surface 102 opposite the sun and to thereby increase
exposure of quadrants 116 and 118 to solar radiation reflected from the sun by reflecting
surface 102.
It is appreciated that the vertical positioning functionality is typically
provided in addition to the solar tracking functionality provided by solar tracking
system 104, and may be either integrated within solar tracking system 104 or provided
in addition to solar tracking system 104. However, it is also appreciated that the vertical
positioning functionality utilizes information provided solely by voltage meters 132,
134, 136 and 138 and does not require information regarding the relative position of
solar electricity generator 100 and the sun in order to reposition reflecting surface 102
opposite the sun.
As shown in Fig. 3B, after generally downward repositioning of
reflecting surface 102 by the vertical positioning functionality, quadrants 112, 114, 116
and 118 are all generally equally exposed to solar radiation reflected from the sun by
reflecting surface 102, thereby causing subsequent measurements of generated electric
voltages VI, V2, V3 and V4 to be generally equal.
It will be appreciated by persons skilled in the art that the present
invention is not limited by what has been particularly shown and described hereinabove.
Rather the scope of the present invention includes both combinations and
subcombinations of various features described hereinabove as well as variations and
modifications thereof which are not in the prior art.

CLAIMS
1. A solar electricity generator comprising:
an array of solar electricity generating elements;
a solar energy concentrating element operative to transmit concentrated
solar radiation from the sun onto said array;
voltage measuring functionality operative to measure at least one of a
total row voltage generated by at least one row of said electricity generating elements in
said array and a total column voltage generated by at least one column of said electricity
generating elements in said array;
vertical positioning functionality operative, in response to ascertaining
by said voltage measuring functionality that a first total row voltage generated by a first
multiplicity of said rows is less than a second total row voltage generated by a second
multiplicity of rows, to generally vertically reposition said solar energy concentrating
element thereby to increase exposure of said first multiplicity of said rows to solar
radiation transmitted from the sun by said solar energy concentrating element; and
horizontal positioning functionality operative, in response to ascertaining
by said voltage measuring functionality that a first total column voltage generated by a
first multiplicity of said columns is less than a second total column voltage generated by
a second multiplicity of columns, to horizontally reposition said solar energy
concentrating element thereby to increase exposure of said first multiplicity of said
columns to solar radiation transmitted from the sun by said solar energy concentrating
element.
2. A solar electricity generator according to claim 1 and wherein said solar
energy concentrating element is a concave reflecting surface.
3. A solar electricity generator according to claim 1 and wherein said solar
energy concentrating element is a concentrating lens.
4. A solar electricity generator according to claim 1 and also comprising
solar tracking functionality operative to utilize astronomical information to rotate and
position said energy concentrating element opposite the sun throughout the day.
5. A solar electricity generator according to claim 1 and wherein said solar
electricity generating elements are serially connected.
6. A solar electricity generator according to claim 1 and wherein said
voltage measuring functionality is operative to continuously measure said row and
column voltages throughout the day.
7. A method for generating solar electricity comprising:
transmitting concentrated solar radiation from the sun onto an array of
solar electricity generating elements;
measuring a total row voltage generated by at least one row of said
electricity generating elements in said array and a total column voltage generated by at
least one column of said electricity generating elements in said array;
in response to ascertaining by said measuring that a first total row
voltage generated by a first multiplicity of said rows is less than a second total row
voltage generated by a second multiplicity of rows, to generally vertically reposition
said solar energy concentrating element thereby to increase exposure of said first
multiplicity of said rows to solar radiation transmitted from the sun by said solar energy
concentrating element; and
in response to ascertaining by said measuring that a first total column
voltage generated by a first multiplicity of said columns is less than a second total
column voltage generated by a second multiplicity of columns, to horizontally
reposition said solar energy concentrating element thereby to increase exposure of said
first multiplicity of said columns to solar radiation transmitted from the sun by said
solar energy concentrating element.
8. A method for generating solar electricity according to claim 7 and
wherein said measuring comprises continuously measuring throughout the day.