Patent Publication Number: US-2012024337-A1

Title: Apparatus facilitating wiring of multiple solar panels

Description:
FIELD OF THE INVENTION 
     Embodiments of the invention relate to solar panel installation, and more particularly to facilitating the wiring together of a plurality of solar panels. 
     BACKGROUND OF THE INVENTION 
     Solar panel installation traditionally involves installing a foundation system (typically a series of posts or footings), and then mounting individual solar panels to the support frame with brackets or clips. Other, more complicated mounting systems have been proposed with multiple parts and complex assemblies. These mounting structures can be difficult to install and worse, expensive to manufacture. Additional problems can result from the diverse materials used to manufacture such mounting systems. 
     In known solar panel-driven power generation systems, sets of solar panels are wired in series to produce a desired voltage. These sets of wired solar panels are called strings. The strings consist of solar panels electrically connected to each other with panel lead wires. Once the strings are wired, sets of strings can be connected in parallel with wire harnesses to add the currents from each string, until the connected sets provide a desired current. Each individual solar panel in such a system, however, must be separately wired in series and/or parallel configurations with other solar panels of the system. Typically, this wiring is performed on-site and one panel at a time, requiring moving equipment, materials and labor along rows of support structures. This is time-consuming and increasingly inefficient with larger scale systems. Thus, a simplified system for wiring a plurality of solar panels together is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a top-down view of a carrier with a plurality of solar panels mounted thereon. 
         FIG. 1B  shows a partial top-down view of a carrier with plugs having a plurality of solar panels mounted thereon. 
         FIG. 2  shows a top-down view of the  FIG. 1B  carrier with the plugs and solar panels aligned along a central axis. 
         FIG. 3A  is a schematic diagram of a portion of a power generation system having a plurality of carriers and showing a possible series electrical connection between adjacent solar panels in a row, with rows of solar panels connected in parallel. 
         FIG. 3B  is a schematic diagram of a single row of solar panels in the  FIG. 3A  system. 
         FIG. 4A  is a top-down view of the  FIG. 2  carrier having a wiring block for interconnecting the plurality of solar panels installed thereon. 
         FIG. 4B  is a close-up top-down view of a portion of the  FIG. 4A  carrier. 
         FIG. 4C  is a side view of the  FIG. 4A  carrier with a wiring block mounted on the interior of the carrier. 
         FIG. 4D  is a side view of the  FIG. 4A  carrier with a wiring block mounted on the exterior of the carrier. 
         FIG. 5  is a top-down view of the wiring block illustrated in  FIGS. 4A and 4B . 
         FIG. 6A  is a schematic diagram of the internal components of a  FIGS. 4A and 4B  wiring block configured to electrically connect solar panels of a carrier in parallel. 
         FIG. 6B  is a schematic diagram of the internal components of a  FIGS. 4A and 4B  wiring block configured to electrically connect solar panels of a carrier in series. 
         FIG. 7  is a top-down view showing a plurality of  FIG. 2  carriers connected together with  FIG. 6A  wiring blocks installed thereon. 
         FIG. 8  is a schematic diagram of a portion of a power generation system having multiple interconnected groups of solar panels on a plurality of carriers 
         FIGS. 9A ,  9 B, and  9 C are schematic diagrams showing series, parallel, and hybrid series/parallel wired carriers, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and which illustrate specific embodiments of the invention. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use them. It is also understood that structural, logical, or procedural changes may be made to the specific embodiments disclosed herein without departing from the spirit or scope of the invention. 
     By way of background,  FIGS. 1A ,  1 B and  2  show examples of solar panel carriers as described in co-pending application Ser. No. 12/______ entitled “A MOUNTING SYSTEM SUPPORTING SLIDABLE INSTALLATION OF A PLURALITY OF SOLAR PANELS AS A UNIT” by John Bellacicco, John Hartelius, Henry Cabuhay, Tom Kuster, Michael Monaco, and Martin Perkins. (attorney docket no. F4500.1001/P1001), filed on even date with this application, the disclosure of which is fully incorporated by reference herein. Solar panel carriers  100 ,  101 ,  200 , respectively shown in  FIGS. 1A ,  1 B and  2 , hold a plurality of solar panels together as a single unit and provide a way of installing the plurality of solar panels as a unit onto a support structure in a manual or semi-automated installation system. Such solar panel carriers (e.g., carrier  100  in  FIG. 1A ) support simplified installation of solar panels, reducing both on-site field labor and equipment movement over an installation site. The solar panel carriers can be easily installed on a support structure, e.g., one comprising a plurality of spaced parallel rails designed to slidably accept the carrier. 
       FIG. 1A  shows one exemplary solar panel carrier  100  with a plurality of solar panels  120   a - 120   h  pre-mounted thereon. The carrier  100  is depicted having 4 rows and 2 columns of solar panels  120   a - h , but is understood that the carrier can have any number of solar panels arranged in an M rows×N column array. Each solar panel  120   a - h  has a set of positive and negative terminals  122   a - h ,  124   a - h , shown in  FIG. 1A  with pigtail wires. The terminals  122   a - h ,  124   a - h  connect to the solar cells within an individual solar panel. The solar panels  120   a - h  in carrier  100  are aligned in the same direction; that is, the terminals  122   a - h ,  124   a - h  on each panel are oriented on right hand side of the solar panels  120   a - h  mounted on carrier  100 . It is, however, of course understood that solar panels  120   a - h  can be oriented in any direction on carrier  100 . 
       FIG. 1B  shows another exemplary solar panel carrier  101  having a different arrangement of positive and negative terminals for solar panels  121   a - h  mounted thereon. The solar panels  121   a - h  of the  FIG. 1B  carrier  101  each have a plug  123   a - h  which contains positive and negative contacts that engage a corresponding receptacle on the carrier  101 . Alternatively, the carrier  101  can have the plug and the panel can have the receptacle. 
       FIG. 2  shows carrier  200  with solar panels  121   a - h  installed thereon, each having plug/receptacles  123   a - h . The solar panels  121   a - h  are installed on carrier  200  in an orientation which aligns plug/receptacles  123   a - h  along a central axis  210 . This type of arrangement simplifies the general location of wiring on the carrier  200  as all the wiring of the solar panels  121   a - h  can be routed along the axis  210 . 
       FIG. 3A  shows one possible arrangement for wiring a plurality of solar panels  120   a - h  of each of carriers  100 ,  100   b ,  100   e  ( FIG. 1A ) together. The panels in each row of arranged carriers  100 ,  100   b ,  100   c  are wired in series to form a solar panel string  310   a ,  310   b ,  310   c ,  310   d . Each solar panel string  310   a ,  310   b ,  310   c ,  310   d  can be equipped with protection device or circuitry  330   a ,  330   b ,  330   c ,  330   d , e.g., a fuse, diode, circuit breaker or other protection device or circuit. 
     As  FIG. 3A  shows, in a first series solar panel string, e.g.,  310   a , the positive and negative terminals  122   a ,  122   b ,  124   a ,  124   b  on solar panels  120   a  and  120   b  on carrier  100  are wired to each other. The rightmost solar panel in the row ( 120   b ) on carrier  100  is wired to the leftmost panel of the next carrier in the series. Wiring continues until a desired number of panels are connected to the series string  310   a  attain a desired string voltage.  FIG. 3B  shows an electrical schematic of a series string  310   a . The positive end of a series solar panel string  310   a  is connected to a protection device or circuit  330   a . The last solar panel in the series on carrier  100   c  provides a negative end of the string  310   a.    
     Because there are multiple rows of solar panels on each carrier  100 ,  100   b ,  100   c , arranged carriers create multiple series solar panel strings  310   a ,  310   b ,  310   c ,  310   d , which may be electrically connected together in parallel to form a group  300  of solar panels, as shown in  FIGS. 3A and 3B . The parallel-wired series strings  310   a ,  310   b ,  310   c ,  310   d  may be electrically connected to a combiner  350 , which aggregates the electrical energy generated by the solar panel strings in group  300  together with that of other solar panel strings to attain a desired voltage and current. The combined electrical output from combiner  350  is fed to an inverter  360 . It should be understood that although 4 series solar panel strings  310   a ,  310   b ,  310   c ,  310   d  of 6 solar panels, 2 from each row of carriers  100 ,  100   b ,  100   c  are shown in  FIG. 3A , any number of series solar panel strings, or panels per string could be used as needed to meet a desired current and/or voltage. 
     While  FIGS. 3A and 3B  show one possible wiring configuration for the solar panels held by each of a plurality of carriers, e.g.,  100 ,  100   b ,  100   c , it should be apparent that wiring the solar panels in the field in the manner illustrated in  FIGS. 3A and 3B  is a time consuming and labor intensive process. 
     In order to facilitate the wiring together of the individual solar panels, e.g.,  120   a - h , mounted on a carrier, e.g.,  100 , and the wiring of a carrier  100  to other carriers, e.g.,  100   b ,  100   c , etc., a wiring block  405  is preferably provided on each carrier, for example carrier  200  of  FIG. 2A  in the manner shown in  FIGS. 4A and 4B .  FIG. 4A  shows wiring block  405  as electrically interconnecting a plurality of solar panels, e.g.,  121   a - h . The solar panels  121   a - h  are preferably mounted on the carrier  200  so that all wiring is near the center line axis  210  of the carrier  200 . The wiring block  405  is connected by wires to each of the plug/receptacles  123   a - h  on the carrier  200 , although the wiring block  405  can be directly wired to pigtail wiring, e.g., terminals/wiring  122   a - h ,  124   a - h  of the  FIG. 1A  carrier  100 , as well. The wires can optionally be run through channels  220   a ,  220   b , provided within or beneath carrier  200 .  FIG. 4B  shows a close up view of solar panel  121   a  on carrier  200  having positive wire  410   a  and negative wire  411   a  from wiring block  405  connected to corresponding plug/receptacle  123   a . Connections from wiring block  405  to plugs/receptacles  123   b ,  123   c  and  123   d  and other panels are also shown. 
     As shown in  FIG. 4C , wiring block  405  can be attached to the carrier  200  in a recess or channel  225  provided within the backside  226  of carrier  200 . Alternatively, as shown in  FIG. 4D , carrier  200  can be mounted directly on a backside  226  of carrier  200 .  FIGS. 4C and 4D  also show channels  220   a ,  220   b  for passage of wires from wiring block  405  to solar panels  121   a - h . Channels  220   a ,  220   b  can be run in the body of carrier  200 , and are shown in  FIGS. 4C-4D  as being positioned above attachment structures  230   a ,  230   b , which are used to mount the carrier  200  to a support structure. 
       FIG. 5  shows the exterior of one embodiment of wiring block  405 . The wiring block  405  is contained in a protective housing  450  which is secured to a carrier, e.g.,  200  by means of threaded screw mounts  402   a ,  402   b  which align with holes or screw mounts on the backside of carrier  200 . Of course it is understood that other securing materials, e.g., glue, Velcro®, or other conventional fasteners can be also used. A plurality of positive and negative wires  410   a - h ,  411   a - h  exit the wiring block  405  to facilitate easy connection to the plug/receptacles, e.g.,  123   a - h , on the carrier  200 . Each pair of positive and negative wires, e.g.,  410   a ,  411   a , is connectable to the respective positive and negative wires on a respective solar panel  121   a . The positive and negative wires  410   a - h ,  411   a - h  are equipped with a corresponding connector  412   a - h ,  413   a - h , which can be one of a Multi Contact 4 (MC4) and Yamaichi YSol 4 connector, which are commonly used with solar panels, for connection to, e.g., plug/receptacles  123   a - h  on the carrier  200 . It is of course understood that other connectors could be used as well. Additionally, a pair of positive and negative conductors  415   a ,  415   b  for connecting adjacent wiring blocks  405  on adjacent carriers  200  are arranged on opposite sides of the wiring block  405 . These too may have Multi Contact 4 (MC4) or Yamaichi YSol 4 connectors attached so as to allow easy connection of one carrier  200  to another. If plugs/receptacles  123   a - h  are note used, the positive and negative wires  410   a - h  can be directly connected to the pigtail wires, e.g.,  122   a ,  124   a  ( FIG. 1A ) on the solar panels. 
       FIG. 6A  shows an interior schematic of one embodiment of a wiring block  405 A configured to electrically connect attached all solar panels  121   a - h  on a carrier  200  in parallel. The plurality of positive and negative wires  410   a - h ,  411   a - h  respectively connect to a corresponding pair of busbars  416 ,  417  using screw-down wire fasteners  421   a - h ,  422   a - h . Other means of fastening the wires to the busbars  416 ,  417  can be used, including, for example, clip fasteners, or soldering. Positive and negative conductors  415   a ,  415   b  are also connected to busbars  416 ,  417 , respectively, to allow interconnection of the solar panels from one carrier with those of another through the electrical connection of the wiring block  405  of one carrier with the wiring block  405  of another carrier, as explained in greater detail below. To prevent damage to the connected solar panels, busbars  416 ,  417  are bridged by a protection circuit, preferably a bypass diode  425 . Generally, current will flow across busbars  416 ,  417  so long as the bypass diode  425  is not tripped by a positive overvoltage. If there is a short to ground on the cartridge, as long as the voltage on the diode is negative, the cartridge will supply current at a diminished level. However, if there is a short to ground where the voltage on the diode is positive then the cartridge will experience reverse voltage bias, tripping the diode. Other protection circuitry comprising blocking diodes, circuit breakers, or fuses can also be used in addition or substituting for to the bypass diode to prevent damage to solar panels within the cartridge, if required. 
       FIG. 6B  shows an interior schematic of another embodiment of a wiring block  405 B configured to electrically connect solar panels  121   a - h  of carrier  200  in series. In  FIG. 6B  the screw-down wire fasteners  421   b - h ,  422   a - g  are wired together to facilitate a series wiring of corresponding solar panels  121   a - h . As an example, fastener  422   a , which corresponds to the negative input from a first solar panel  121   a , is wired to fastener  421   b , which corresponds to the positive input from a second solar panel  121   b . The positive input from the first solar panel  121   a  may connect to a bypass diode, fuse, circuit breaker, or other protection device or circuit  425  to cross-connector  415   a  for positive output. At the opposite end of the series, the negative input from the last solar panel  121   h  is connected to negative conductor  415   b  for negative output from carrier  200 . Although  FIGS. 6A and 6B  respectively illustrate wiring blocks  405  which interconnect the solar panels of a carrier in parallel or series, the wiring block  405  can also be internally configured to wire some panels on a carrier in series and others in parallel. 
       FIG. 7  shows a set of  FIG. 2  carriers  200 ,  200   b  (and associated solar panels  121   a - h  and plug/receptacles  123   a - h ) connected in series via the positive and negative conductors  415   a ,  415   b  connected to their wiring blocks  405 .  FIGS. 9A and 9B  show electrical schematic diagrams of series and parallel wired  FIG. 2  carriers  200 ,  200   b  with wiring blocks  405 A ( FIG. 9A) and 405B  ( FIG. 9B ) wired in parallel and series, respectively.  FIG. 9C  shows a hybrid wiring scheme in wiring blocks  405 C which two sets of four solar panels on a carrier  200 ,  200   b  are wired in series and the sets then are wired in parallel, with the carriers  200 ,  200   b  then being wired in series. Alternatively, the solar panels could be wired in parallel and the sets in series. 
       FIG. 8  shows a power generating system comprising a plurality of carriers  200 - 200   o  formed into carrier groups  800 ,  800   b ,  800   c , and  800   d  which are mounted on support rails  840   a ,  840   b ,  840   c ,  840   d . Each of the carriers  200 - 200   o  contains a respective wiring block  405  ( FIG. 6A ). The solar panels of each carrier are wired in parallel through a wiring block  405 , while the carriers of each group  800 ,  800   b ,  800   c ,  800   d  are wired in series. For example, the carriers  200 ,  200   a ,  200   b ,  200   c  are wired in series. The carrier groups  800  and  800   b  are respectively wired in parallel to a positive busway  830   a  and a negative busway  830   b , and the carrier groups  800   c  and  800   d  are wired in parallel to fused positive busway  830   c  and fused negative busway  840   d , or individually home run to a combiner, e.g.,  350 . 
     The positive and negative busways  830   a ,  830   b ,  830   c ,  830   d  form an electrical group. As shown in  FIG. 8 , each of the positive busways  830   a ,  830   c  may be respectively mounted on to one of the spaced parallel rails  840   a ,  840   c , which mount the carriers, and the negative busways  830   b ,  830   d  are mounted to the other of the carrier mounting rails  840   b ,  840   d . Alternatively, the busways  830   a ,  830   b  can run along the ground or on a roof or side of a building, depending on where the carriers are installed. The carrier groups  800   a ,  800   b  and  800   c ,  800   d  are wired in parallel by a combiner  350  to an inverter  360 . 
     Generally, a semi-automated carrier mounting and delivery system may be used at the end of each solar array row to push carriers, e.g., those in groups  800 ,  800   b ,  800   c ,  800   d , in to place on rails  840   a ,  840   b . One such mounting and delivery system is described in more detail in co-pending application Ser. No. 12/______, entitled “AUTOMATED INSTALLATION SYSTEM FOR AND METHOD OF DEPLOYMENT OF PHOTOVOLTAIC SOLAR PANELS, to John Bellacicco, Tom Kuster, Michael Monaco and Tom Oshman (attorney docket no. F4500.1002/P1002), filed on even date with this application, the disclosure of which is incorporated by reference herein. As discussed in that application, each carrier mounts and supports a plurality of solar panels as a unit, is set on the rails by a robotic system and moved along, thereby simplifying installation time and lowering cost. Once in place, since each of the solar panels on the carriers are pre-wired, only carrier to carrier wiring needs to be done on site. To further facilitate installation, positive and negative male/female electrical connectors can be provided on the edge of the carriers e.g.,  200 , so that when the carriers are pushed into place, the male and female connectors interconnect the wiring blocks  405  on the carriers, e.g.,  200 . Then all that is needed to do is to connect each carrier group, e.g.,  800  to positive and negative busways, e.g.,  830   a ,  830   b  or combiner  350 , substantially reducing the on-site labor required for installation. 
     While several embodiments have been described in detail, it should be readily understood that the invention is not limited to the disclosed embodiments. Rather the embodiments can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described. Although certain features have been described with some embodiments of the carrier, such features can be employed in other embodiments of the carrier as well. Accordingly, the invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.