Terrestrial solar array including a rigid support frame

Abstract

A concentrator photovoltaic solar cell array system includes a central support mountable on a surface and a solar cell array including triple junction III-V semiconductor compound solar cell receivers and a support frame coupled to the solar cell array and carried by, and rotatable with respect to, the central support about an axis orthogonal to the central longitudinal axis. The support frame can include (i) a first frame assembly coupled to the solar cell array and (ii) a second frame assembly coupled to the first frame assembly arranged to increase the rigidity thereof. The system also has an actuator for rotating the central support and the support frame as well as pivoting the support frame so as to adjust its angle with respect to the earth's surface, so that the solar cell array is maintained substantially orthogonal to the rays from the sun as the sun traverses the sky.

1 . A concentrator photovoltaic solar cell array system for producing energy from the sun using one or more sun-tracking solar cell arrays, the system comprising:
 a central support mountable on a surface, and rotatable about its central longitudinal axis;   a substantially planar solar cell array including a plurality of triple junction III-V semiconductor compound solar cell receivers;   a support frame coupled to the solar cell array and carried by and rotatable with respect to the central support about an axis orthogonal to the central longitudinal axis, the support frame comprising:
 a first frame assembly coupled to the solar cell array; and 
 a second frame assembly coupled to the first frame assembly arranged to increase the rigidity of the first frame assembly; and 
   an actuator for rotating the central support and the support frame so that the solar cell array is maintained substantially orthogonal to the rays from the sun as the sun traverses the sky.   
     
     
         2 . A system as claimed in  claim 1  wherein the second frame assembly comprises a truss. 
     
     
         3 . A system as claimed in  claim 1  wherein the second frame assembly comprises two shorter beams and one longer beam, wherein a first end of each shorter beam is coupled to the first frame assembly and a second end of each shorter beam is coupled to the longer beam. 
     
     
         4 . A system as claimed in  claim 1  wherein the second frame assembly is arranged along the greatest perpendicular dimension of the solar cell array. 
     
     
         5 . A system as claimed in  claim 2  wherein the truss is arranged along the greatest perpendicular dimension of the solar cell array. 
     
     
         6 . A system as claimed in  claim 2  wherein the truss comprises a lower chord, an upper chord substantially parallel to the lower chord, two or more substantially parallel brace chords coupled to the upper and lower chords, and at least one diagonal chord disposed between two brace chords and coupled to the upper and lower chords. 
     
     
         7 . A system as claimed in  claim 2  wherein the truss comprises a lower chord, an upper chord substantially parallel to the lower chord, and at least one diagonal chord coupled to the lower chord and upper chord. 
     
     
         8 . A system as claimed in  claims 6  or  7  wherein the lower chord comprises at least a portion of the first frame assembly. 
     
     
         9 . A system as claimed in  claims 6  or  7  wherein the first frame assembly comprises a generally rectangular frame member comprising upper and lower parallel members oriented in a direction substantially parallel to the surface to which the center support is mountable, wherein the upper chord is coupled to the lower parallel member by at least one truss support member. 
     
     
         10 . A system as claimed in  claim 6  wherein the brace chords are arranged substantially orthogonal to a plane defined by the solar cell array. 
     
     
         11 . As system as claimed in  claim 7  wherein the direction of the perpendicular distance from the lower chord to the upper chord is substantially orthogonal to a plane defined by the solar cell array. 
     
     
         12 . A system as claimed in  claims 6  or  7  wherein the width of the lower chord is substantially the same as the width of the solar cell array, wherein the width of the solar cell array is measured in a direction substantially parallel to the surface to which the central support is mountable. 
     
     
         13 . A system as claimed in  claim 1  wherein the second frame assembly is arranged in a direction orthogonal to a plane defined by the first frame assembly. 
     
     
         14 . A system as claimed in  claim 2  wherein the truss is arranged in a direction orthogonal to a plane defined by the first frame assembly. 
     
     
         15 . A system as claimed in  claim 1  wherein the second frame assembly is arranged in a direction orthogonal to a plane defined by the solar cell array. 
     
     
         16 . A system as claimed in  claim 2  wherein the truss is arranged in a direction orthogonal to a plane defined by the solar cell array. 
     
     
         17 . A system as claimed in  claim 1  wherein the width of the first frame assembly and the width of solar cell array are substantially the same, wherein the width of the solar cell array is measured in a direction substantially parallel to the surface to which the central support is mountable. 
     
     
         18 . A system as claimed in  claim 2  wherein the truss is mounted above the vertical center of the solar cell array. 
     
     
         19 . A system as claimed in  claim 1 , wherein the solar cell array comprises a plurality of solar cells and a corresponding plurality of Fresnel lenses each of which is disposed over a single solar cell for concentrating by a factor in excess of 500× the incoming sunlight onto the solar cell and producing in excess of 13 watts of DC power at AM 1.5 solar irradiation per solar cell with conversion efficiency in excess of 37%. 
     
     
         20 . A system as claimed in  claim 1 , wherein the central support is constituted by a first member provided with means for mounting the central support on the surface, and a second member rotatably supported by, and extending upwardly from, the first member. 
     
     
         21 . A system as claimed in  claim 1 , wherein the support frame is mounted on a cross member which is rotatably mounted with respect to the second member of the central support about an axis orthogonal to the central longitudinal axis. 
     
     
         22 . A system as claimed in  claim 1 , wherein the first frame assembly comprises a generally rectangular frame member having a plurality of parallel support struts that are parallel to the shorter sides of the rectangular frame member. 
     
     
         23 . A system as claimed in  claim 22 , wherein the first frame assembly further comprises a plurality of oblique support struts. 
     
     
         24 . A system as claimed in  claim 1  wherein the solar cell array is arranged to produce approximately 25 kW peak DC power on full illumination. 
     
     
         25 . A system as claimed in  claim 1  comprising at least one inclined strut coupled to the central support and the first frame assembly. 
     
     
         26 . A concentrator photovoltaic solar cell array system for producing energy from the sun using a plurality of sun-tracking solar cell arrays, comprising:
 a central support mountable on a surface and rotatable about its central longitudinal axis;   a rectangular solar cell array having an aspect ratio between 1:3 and 1:5, with the longitudinal of the array substantially parallel to the surface for producing in excess of 25 kW peak DC power on full illumination and including a plurality of triple junction III-V semiconductor compound solar cell receivers mounted on the support frame; and   a support frame coupled to the solar cell array and carried by and rotatable with respect to the central support about an axis orthogonal to the central longitudinal axis, the support frame comprising:
 a first frame assembly coupled to the solar cell array; and 
 means for increasing the rigidity of the first frame assembly; and 
   an actuator for rotating the central support and the support frame so that the solar cell array is maintained substantially orthogonal to the rays from the sun as the sun traverses the sky.   
     
     
         27 . The system of  claim 26  wherein the means for increasing the rigidity of the first frame assembly prevents a deflection greater than 1 degree near the perimeter of the solar cell array. 
     
     
         28 . A concentrator photovoltaic solar cell array system for producing energy from the sun using one or more sun-tracking solar cell arrays, the system comprising:
 a central support mountable on the ground, and being capable of rotation about its central longitudinal axis;   a rectangular solar cell array for producing in excess of 25 kW peak DC power on full illumination including a plurality of triple junction III-V semiconductor compound solar cell receivers;   a support frame coupled to solar cell array and carried by and rotatable with respect to the central support about an axis orthogonal to the central longitudinal axis, the support frame comprising:
 a rectangular frame assembly coupled to the solar cell array comprising first and second long members aligned in a direction substantially parallel to the direction of the largest perpendicular dimension of the solar cell array and comprising first and second short members aligned in a direction substantially perpendicular to the direction of the largest perpendicular dimension of the solar cell array; and 
 a truss assembly coupled to at least one of the first and second long members, the truss assembly comprising a lower chord, an upper chord substantially parallel to the lower chord, and at least one diagonal chord coupled to the lower chord and upper chord; and 
   an actuator for rotating the central support and the support frame so that the solar cell array is maintained substantially orthogonal to the rays from the sun as the sun traverses the sky.   
     
     
         29 . The system of  claim 28  wherein the lower chord comprises one of the first and second long members. 
     
     
         30 . The system of  claim 28  wherein the direction of the perpendicular distance from the lower chord to the upper chord is substantially orthogonal to a plane defined by the solar cell array. 
     
     
         31 . The system of  claim 28  wherein the width of the rectangular frame assembly is approximately the same as the largest perpendicular dimension of the solar cell array. 
     
     
         32 . The system of  claim 28  wherein the truss assembly is located above the vertical center of the solar cell array. 
     
     
         33 . The system of  claim 28  wherein the first and second long members and first and second short members are formed as a unitary structure.