Patent Publication Number: US-2022231637-A1

Title: Novel photovoltaic panel design to enable low voltage and high output power in an energy generating photovoltaic system

Description:
FIELD OF THE INVENTION 
     This application is related to the field of expandable solar power generating systems. More specifically, this application relates to a novel photovoltaic panel design within an expandable solar system to enable operation of the solar system within a safe range of operating voltages. 
     BACKGROUND 
     The following description includes information that may be useful in understanding the disclosure set forth herein. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. 
     All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. 
     Many buildings, vehicles (such as recreational vehicles), pergolas, and boats use visors, awnings, shade screens, canopies or blinds to protect against solar radiation, provide shade and keep buildings or vehicles cool. 
     Incorporating solar generation capabilities on these shade-providing structures is advantageous because it provides the dual benefit of blocking sunlight while simultaneously using that impinging sunlight to generate electrical power. 
     As an example, vehicles such as RVs, use awnings for shade. Users of RVs also have a strong need for clean and silent off-grid power that enables the use of RVs in remote locations for extended periods of time. 
     Traditionally, solar panels are installed on roofs of RVs, but roofs typically have very limited available area for panel installation due to the presence of an air conditioner, air conditioner vents, bathroom vents, refrigerator vent, bathroom skylights, etc. at different locations on the roof. 
     This lack of available roof area greatly limits the number of solar panels that can be installed on a given roof, and hence the total amount of power generated by the installed solar system. 
     The present disclosure sets forth embodiments of a solar awning, such as for use in an RV, that overcome the above-mentioned constraints. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates one embodiment of a layout of a solar system and the sub-systems within the solar system. 
         FIG. 2  illustrates a solar panel with two separate and independent electrical solar circuits 
         FIG. 3  illustrates a sub-set of solar panels in one sub-system that are interconnected to form two separate and independent electrical strings 
     
    
    
     DETAILED DESCRIPTION 
     The photovoltaic panel and the novel layout and interconnection schemes disclosed herein may be equally used in static (fixed) photovoltaic systems, as well as expandable and retractable solar structures that are within close proximity of human beings and therefore accessible by touch. 
     A solar system integrated into structures such as awnings, shade screens, and canopies is in relatively close proximity to human contact. Hence, there is a need to maintain low (safe) voltage output from a solar awning. But there is also a need to maximize total power of the awning, which effectively results in an increase in the total number of solar panels. 
     Increase in the total number of panels results in a correspondingly increase of the number of panels that are electrically connected in series in a given electrical ‘string’ of panels, hence increasing the string voltage. 
     Both of the above-mentioned needs for low voltage and more power can only be met by reducing the number of panels electrically connected in series in a given electrical string, and correspondingly increasing the number of electrical strings in the awning. 
     However, an increase in the number of strings results in a corresponding increase in number of wires in the solar system. 
     An increase in the number of wires requires more space for wire management within the awning, but there is a strong constraint on the amount of available space in the awning due to the highly compact and retracting nature of the awning; thereby severely constraining the number of wires that can be accommodated in the design. For example, such awnings are described in U.S. Pat. No. 10,560,050, entitled “Innovative Energy Generating Photovoltaic Awning”, and U.S. patent application Ser. No. 16/932,751, entitled “Energy Generating Photovoltaic Awning with Scissor Mechanism and Tilting Photovoltaic Panels”, both assigned to the applicant of the present application, EvoluSun, Inc., and are both expressly incorporated herein by reference in their entirety. 
     The embodiments disclosed herein overcome the above constraints; and results in a low voltage without sacrificing the total output power of the awning. 
     In some embodiments, the awning solar system is comprised of a plurality of solar sub-systems which in turn comprise of a plurality of solar panels. 
     In some embodiments, solar panels are grouped into mechanical modular sub-systems such that each sub-system is comprised of a plurality of solar panels, and sub-systems are placed next to one another. For the embodiment shown in  FIG. 1 , solar system ( 400 ) consists of subsystems  100 ,  150 ,  200 ,  250  and  300 . Although  FIG. 1  illustrates a solar system with 5 subsystems, any number of subsystems may be incorporated into a system without deviating from the spirit or scope of the invention. 
     Each sub-system is further comprised of two or more solar strings; and each string consists of a plurality of solar panels connected serially to form an electrical circuit. 
     The present disclosure sets forth herein a solar panel design that comprises of two separate and independent solar electrical circuits housed within a single solar panel; henceforth referred to a split-circuit panel. 
     A split-circuit panel offers the unique advantage of reducing the voltage output of a solar panel by half while not impacting the total power output, and also not impacting the mechanical support structure to which the panels are connected. 
     Furthermore, because each of the two independent solar cell circuits within the solar panel is electrically connected to a bypass diode which ensures protection of individual solar cells against reverse-bias conditions that can arise due to multiple reasons while in operation; another benefit of the split-circuit panel is the reduction in number of solar cells per bypass diode to half of those in a standard solar panel that comprises of only one solar cell circuit. This leads to an inherently more robust solar panel that is more adaptive to a solar cell reverse bias condition. Another benefit of a split-circuit design is the simplification of the mechanical and electrical assembly of solar panels within a mechanical enclosure, and also the reduction in the unique number of mechanical components needed to mount the solar panels. Mechanically speaking, the solar panel can use the same mechanical mounting components on a given short side of the solar panel because a junction box will always be present on the short side even if the solar panel is rotated 180 degrees to move the right slide to the left and the left side to the right. 
     Electrically, this simplification results from the rotational symmetry of the electrical circuit layout within the solar panel. Specifically, the solar panel can rotated by 180 degrees around the center of the panel, and the resulting new mechanical orientation has the same location of the positive and negative terminals as the original orientation. 
     Yet another benefit that results from the mechanical and electrical simplification of the solar panel design is the reduced error in assembly of the solar panels, because a specific orientation of the solar panels is not required to achieve correct assembly. 
     In one embodiment, a sub-system comprised of plurality of split-circuit solar panels are connected in series on either side of a solar panel to create two independent electrical strings from a set of solar panels (See  FIG. 3 ) 
     Moving to a detailed description of the FIGs;  FIG. 1  shows a schematic of a solar system ( 100 ) comprising of sub-systems ( 105 ,  110 ,  115 ,  120 , and  125 ) with a plurality solar panels inside each sub-system. 
       FIG. 2  shows a solar panel ( 200 ) comprising of a plurality of solar cells that are interconnected to form two separate and independent electrical circuits ( 210 ,  220 ). One circuit ( 210 ) has positive and negative terminals ( 20 ,  21 ) terminating on the left side of the solar panel; and the other circuit ( 220 ) has the positive and negative terminals ( 22 ,  23 ) terminating on the right side of the solar panel. 
     Circuit  210  of  FIG. 2  is shown as comprising of a plurality of solar cells ( 10 ,  11 ,  12 ,  13 ,  14 ) that are interconnected with a plurality of electrically conducting connectors ( 31 ,  32 ,  33 ,  34 ). A bypass diode ( 40 ) is connected across the electrical terminals of circuit  210 . 
     Similarly, the second circuit ( 220 ) is shown as comprising of a plurality of solar cells ( 15 ,  16 ,  17 ,  18 ,  19 ) that are interconnected with a plurality of electrically conducting connectors ( 35 ,  36 ,  37 ,  38 ). A bypass diode ( 41 ) is connected across the electrical terminals of circuit  220 . 
       FIG. 3  shows an embodiment for interconnection of electrical circuits across a plurality of solar panels. In this embodiment, the solar panels ( 310 ,  320 ,  330 ) are electrically connected. Circuit  30  in solar panel  310 , circuit  32  in solar panel  320 , and circuit  34  in solar panel  330  are connected to form one electrical string. Circuit  31  in solar panel  310 , circuit  33  in solar panel  320 , and circuit  35  in solar panel  330  are connected to form another electrical string. Circuit  30  is connected to circuit  32  by means of electrical conductor  42 , and circuit  32  is connected to circuit  34  by means of electrical conductor  44 . Similarly, circuit  31  is connected to circuit  33  by means of electrical conductor  43 , and circuit  33  is connected to circuit  35  by means of electrical conductor  45 . Circuits  30 ,  31 ,  32 ,  33 ,  34 , and  35  respectively have bypass diodes  50 ,  51 ,  52 ,  53 ,  54 , and  55  connected in parallel to solar cells comprised within the circuits. 
     Although the present invention has been described in terms of specific exemplary embodiments, it will be appreciated that various modifications and alterations might be made by those skilled in the art without departing from the spirit and scope of the invention.