Patent Publication Number: US-11394345-B2

Title: PV module power electronics mounting system with compression spring

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 15/267,894, which was filed on Sep. 16, 2016 and which claims benefit of U.S. provisional patent application Ser. No. 62/219,884, entitled “PV Module Power Electronics Mounting System with Compression Spring” and filed Sep. 17, 2015, which is herein incorporated in its entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     Solar panels, or photovoltaic (PV) modules, convert energy from sunlight received into direct current (DC). In some solar power systems, the PV modules may be coupled to power conditioning units (PCUs), such as DC-DC converters or DC-AC inverters, in a distributed architecture; i.e., one PCU per PV module. In such systems, each PCU may be mounted to the face (i.e., backsheet surface or superstrate) of the corresponding PV module. 
     One technique known in the art for mounting a PCU to a PV module face is a sliding rail backsheet mount system. In such a system, mounting rails are adhered to the PV module face and the PCU can be slid along the rails into position. However, the sliding rail system requires almost twice the footprint of the PCU in order to insert/remove the PCU (due to the PCU having to slide up/down the rails) and maintains the inverter in a fixed position which respect to the PV module which may not be ideal for shipping combined PCU/PV module assemblies. 
     Therefore, there is a need in the art for an apparatus for efficiently mounting a power conditioner to a PV module frame 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention generally relate to an apparatus for mechanically coupling a power conditioning unit (PCU) to a photovoltaic (PV) module substantially as shown and/or described in connection with at least one of the figures, as set forth more completely in the claims. 
     Various advantages, aspects and novel features of the present disclosure, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG. 1  is a block diagram depicting a physical layout of a photovoltaic (PV) system in accordance with one or more embodiments of the present invention; 
         FIG. 2  is a top angled perspective view of a PCU mounting assembly coupled to a PCU in accordance with one or more embodiments of the present invention; 
         FIG. 3  is a top angled perspective view of a PCU mounting assembly in accordance with one or more embodiments of the present invention; 
         FIG. 4  is a top angled perspective view of a PCU mounting assembly in accordance with another embodiment of the present invention; and 
         FIG. 5  is an angled bottom view of a PCU mounting assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention generally relate to a mounting assembly for mounting a power conditioning unit (PCU) to a photovoltaic (PV) module. The mounting assembly comprises a base member having multiple retention members for retaining the PCU. The mounting assembly further comprises at least one compression spring that maintains the PCU in one or two positions with respect to the PV module and allows the PCU position to be dynamically changed. In a first position, the PCU is pressed flat against the backsheet of the PV module, while in the second position an airgap is present between the PCU and the PV module backsheet for thermal management. 
       FIG. 1  is a block diagram depicting a physical layout of a photovoltaic (PV) system  100  in accordance with one or more embodiments of the present invention. 
     The PV system  100  comprises a plurality of power conditioning units (PCUs)  102   1 ,  102   2  . . .  102   n  (collectively PCUs  102 , or power electronics  102 ), a plurality of PV modules  104   1 ,  104   2  . . .  104   n  (collectively PV modules  104 ), and a plurality of PCU mounting assemblies  150   1 ,  150   2  . . .  150   n  (collectively PCU mounting assemblies or mounting assemblies  150 ). 
     Each PV module  104   1 ,  104   2  . . .  104   n  comprises a structural frame  160   1 ,  160   2 . . .  160   n , respectively, collectively referred to as frames  160 . Each of the frames  160  surrounds the perimeter of the corresponding PV module  104  and may be constructed of any rigid material, such as aluminum, rigid plastic, and the like, or any combination of such rigid materials. The frames  160  of the PV modules  104  are generally coupled flush with the frames  160  of neighboring PV modules  104  in a horizontal direction. 
     Each PCU  102   1 ,  102   2  . . .  102   n  is mechanically coupled to a corresponding PV module  104   1 ,  104   2  . . .  104   n  via a corresponding mounting assembly  150   1 ,  150   2  . . .  150   n , respectively, in a one-to-one correspondence. Each mounting assembly  150   1 ,  150   2  . . .  150   n  is adhered to the surface of a respective PV module backsheet  180   1 ,  180   2  . . .  180   n  (i.e., the rear PV module face that is not exposed to sunlight) for retaining the corresponding PCU  102   1 ,  102   2  . . .  102   n  proximate the PV module  104   1 ,  104   2  . . .  104   n . Each combined PV module  104 /PCU  102 /mounting assembly  150  may be referred to as a power module assembly. 
     In accordance with one or more embodiments of the present invention, each of the mounting assemblies  150   1 ,  150   2  . . .  150   n  comprises one or more compression springs  130   1 ,  130   2  . . .  130   n  (collectively compression springs  130 ), respectively, that enables the corresponding PCU  102  to be pressed flat to respective the PV module backsheet  180   1 ,  180   2  . . .  180   n  (collectively referred to as PV module backsheet  180 ), for example during shipping, and, once installed, to be retained proximate the corresponding PV module  104  with a defined gap between the PCU  102  and the PV module  104  that allows airflow between the components for thermal management of the PCU  102  and the PV module  102 . In some embodiments, the gap may be on the order of 5-25 mm and may depend on topology features of the PCU enclosure. 
     In addition to being mechanically mounted to the PV modules  104 , the PCUs  102   1 ,  102   2  . . .  102   n  are electrically coupled to the PV modules  104   1 ,  104   2  . . .  104   n  to receive the generated DC power from the corresponding PV module  104 . Examples of such coupling may be found commonly assigned U.S. patent application Ser. No. 14/793,164, entitled “Photovoltaic Module with Integrated Power Electronics”, filed Jul. 7, 2015, which is herein incorporated in its entirety by reference. 
     In some embodiments, the PCUs  102  are DC-AC inverters for inverting DC power generated by the PV modules  104  to AC power. In such embodiments, the PCUs  102  are coupled to a load center  108  via an AC bus  106  for distributing the AC output produced by the PCUs  102 . The load center  108  may house connections between an AC commercial power grid distribution system and the AC bus  106  for coupling the generated AC power to the grid. Additionally or alternatively, the generated AC power may be coupled to commercial and/or residential systems via the load center  108 , as well as stored for later use (for example, the generated energy may be stored utilizing batteries, heated water, hydro pumping, H 2 O-to-hydrogen conversion, or the like). 
     In other embodiments, the PCUs  102  may be other types of power conditioning units; for example, the PCUs  102  may be DC-DC converters and the bus  106  may carry DC energy to a DC power distribution system and/or to a single centralized DC-AC inverter. The generated DC power may additionally or alternatively be supplied directly to commercial and/or residential systems via the load center  108 , as well as stored for later use (for example, the generated energy may be stored utilizing batteries, heated water, hydro pumping, H 2 O-to-hydrogen conversion, or the like). 
     In one or more alternative embodiments, the mounting assemblies  150  retain other types of electronics, such as LED drivers, DC optimizers, or other electronics that might have special PV mounting or thermal requirements. 
       FIG. 2  is a top angled perspective view of a PCU mounting assembly  150  coupled to a PCU  102  in accordance with one or more embodiments of the present invention. The PCU mounting assembly  150  comprises a base member  210  generally shaped as a U-shaped rectangle and sized such that the outer edge of the base member  210  is slightly larger than the perimeter of the PCU  102 . The base member  210  is formed from a non-electrically conductive (i.e., insulating) material, such as polycarbonate (PC), p-phenylene oxide (PPO™)+polystyrene (PS), p-phenylene ether (PPE), NORYL™, LEXAN™, or the like, and is adhered to the rear face of the corresponding PV module  104  (i.e., on the side of the PV module  104  not exposed to sunlight) as described further below with respect to  FIG. 5 . 
     The base member  210  further comprises a plurality of PCU retention members  220 - 1 ,  220 - 2 ,  220 - 3 , and  220 - 4 , collectively referred to as PCU retention members  220 . The PCU retention members  220 - 1 ,  220 - 2 ,  220 - 3 , and  220 - 4  extend perpendicular from the face to the base member  210  to retain the PCU  102 . Each of the PCU retention members  220  comprises at least one PCU retention feature, such as a latch, a clip (e.g., a spring clip), a trap (to hold a protuberance of the PCU  102 ), and the like to mechanically secure the PCU  102  to the PCU mounting assembly  150 . In some embodiments, such as the embodiment depicted in  FIG. 2 , the PCU retention members  220 - 1  and  220 - 2  comprise latches  222 - 1  and  222 - 2 , respectively, each having a spring mechanism that retains the PCU  102  until the spring is displaced (e.g., by a tool, finger, or the like) in order to remove the PCU  102  as needed. Additionally, the PCU retention members  220 - 3  and  220 - 4  each define apertures, or “traps”, suitably sized and shaped to accommodate corresponding protuberances of the PCU  102 . For example, as shown in detail in  FIG. 2 , a trap  224 -A of the PCU retention member  220 - 4  accommodates a PCU protrusion  226 -A for retaining the PCU  102 . 
     The PCU mounting assembly  150  further comprises one or more compression springs  130  that enable the PCU  102  to be maintained in one of two positions with respect to the PV module backsheet  180  as well as changed from one position to the other; i.e., the position of the PCU  102  with respect to the PV module backsheet  180  can be dynamically changed while the PCU  102  is mounted on the PV module backsheet  180 . 
     As depicted in  FIG. 2 , the compression spring  130  is substantially shaped as a flat-bottom “V” (e.g., similar to a leaf spring) where the flat bottom is disposed on the top side of the arm of the base member  210  that runs between the PCU retention members  220 - 1  and  220 - 4 . The obtuse-angled arms of the compression spring  130  are suitably sized and shaped such that the free ends of the arms contact the PCU  102  to maintain the PCU  102  is one of two positions with respect to the PV module backsheet  180 . In the first position, the PCU  102  is pressed flat to the PV module backsheet  180  such that it is not proud of the PV module frame, for example in shipping, if laid on the ground or racking, and the like. The PCU  102  is maintained in the first position when pressed toward the PV module backsheet  180  or weighted down toward the PV module backsheet  180 . For example, a restraining strap may be used to press the PCU  102  toward the PV module backsheet  180 , or multiple PV module  104 /PCU  102  assemblies may be stacked during shipping such that the compression spring  130  for each PCU mounting assembly  150  is compressed by the next PV module  104  above in the stack (or in the case of a vertical array the neighboring PV module  104  to the left or right). The PCU  102  moves from the first position to the second position when force applied to the PCU  102  toward the PV module backsheet  180  is removed, causing the compression spring  130  to automatically spring out (for example, by releasing a restraining strap or unstacking stacked PV module  104 /PCU  102  assemblies), resulting in the second position as depicted in  FIG. 2 . The compression spring  130  maintains the PCU  102  in the second position such that an air gap  260  exists between the PCU  102  and the PV module backsheet  180  for improved thermal management of the PCU  102  and PV module backsheet  180 . The air gap is generally on the order of  10 - 20 mm, although in other embodiments it may be larger or smaller. 
     The PCU mounting assembly  150  enables the PCU  102  to be attached with very tight lateral clearances to the PV module frame  160  and racking, whereas a sliding rail system requires almost twice the footprint when inserting and removing the PCU  102  from the rails due to the travel down the rails. 
       FIG. 3  is a top angled perspective view of a PCU mounting assembly  150  in accordance with one or more embodiments of the present invention. As previously described, the PCU mounting assembly  150  comprises the base member  210 , the PCU retention members  220 , and the latches  222 . The traps  224 -A and  224 -B are defined by the PCU retention members  220 - 4  and  220 - 3 , respectively. 
     As depicted in  FIG. 3 , the PCU mounting assembly  150  additionally comprises a first compression spring  130 -A and a second compression spring  130 -B (collectively referred to as compression springs  130 ) disposed along the parallel arms of the base member  210  such that the flat bottoms of the compression springs  130  are adhered to the surface of the base member  210  and the obtuse-angled arms of the compression springs  130  extend vertically from the base member  210  and parallel to the base member arms. In some embodiments, the ends of the compression spring arms may be flattened to lie flush against the PCU  102 . 
     Generally, the compression springs  130  are formed from plastic since it does not need to be grounded and cannot be energized by a cut wire or cable, although in some embodiments one or both of the compression springs  130  may be an insulated metal spring might having a thick polymer coating. 
     The compression springs  130  can be assembled by any suitable means to the base member  210  in a secondary step. For example, the compression springs  130  may be adhered to the base member  210  by one or more of glue, screws, and the like. In some other embodiments, a different number of compression springs  130  may be used and/or one or more of the compressions springs  130  may be located in a different position on the base member  210 . Additionally or alternatively, one or more of the compression springs  130  may be shaped differently; for example, one or more compression springs  130  may be shaped as a coil. 
     The base member  210  may be made with a simple two-part cavity as the undercut regions can be created by pistons from the lower mold wall. 
       FIG. 4  is a top angled perspective view of a PCU mounting assembly  150  in accordance with another embodiment of the present invention. As previously described, the PCU mounting assembly  150  comprises the base member  210 , the PCU retention members  220  and the latches  222 , and the traps  224 -A and  224 -B are defined by the PCU retention members  220 - 4  and  220 - 3 , respectively. 
     As depicted in  FIG. 4 , the outer edges of the base member arms are recessed and the first and second compression springs  130  are disposed along the member arms outer edges such that the obtuse-angled arms of the compression springs  130  extend vertically from the base member  210  and parallel to the base member arms, and in a position to contact the PCU  102  when it is mounted to the PCU mounting assembly  150 . In the embodiment depicted in  FIG. 4 , the compression springs  130  are molded into the base member. Although the compression springs  130  are shown in  FIG. 4  along the outer edges of the base member arms, in other embodiments one or both of the compression springs  130  may be in a different location on the base member  210 , for example on top of the base member arms. Additionally or alternatively, a different number of compression springs  130  and/or differently shaped compression springs  130  may be used. 
       FIG. 5  is an angled bottom view of a PCU mounting assembly  150 . As previously described, the PCU mounting assembly  150  comprises the base member  210 , the PCU retention members  120 , and the compression springs  130 . 
     A plurality of adhesive regions  502 - 1 ,  502 - 2 ,  502 - 3 , and  502 - 4  (collectively referred to as adhesive regions  502 ) are located on the underside of the base member  210  for dispensing adhesive to adhere the base member  210  to the PV module backsheet  180 . As depicted in  FIG. 5 , the adhesive regions  502  are shaped as hollow oblong ovals with one adhesive region  502  corresponding to each of the four corners of the base member  210 ; e.g., in the embodiment of  FIG. 5 , the adhesive regions  502 - 1 ,  502 - 2 ,  502 - 3 , and  502 - 4  are disposed on the backsheet-facing side of the base member  210  underneath the PCU retention members  220 - 1 ,  220 - 2 ,  220 - 3 , and  220 - 4 , respectively. In other embodiments, different sizes, shapes, and/or numbers of adhesive regions  502  may be used, as well as different locations for one or more of the adhesive regions. 
     The base member  210  defines a tape region  504  along the underside of the base portion between the base member arms. The tape region  504  is a recessed region defined for double-stick tape to be applied in order to adhere the base member  210  to the PV module backsheet  180  while the applied adhesive cures. In other embodiments, a different number of tape regions  504  may be used as well as differently sized and/or located tape regions  504 . 
     Each corner of the base member  210  defines a rectangular-shaped cut-out  506 - 1 ,  506 - 2 ,  506 - 3 , and  506 - 4 , collectively referred to as cut-outs  506 . The cut-outs  506  are required to allow the latches  222  and traps  224  to be formed since they are undercut regions and need a part of the mold tool to penetrate the base member  210  in order to support the undercut features in the mold. Alternatively, sliding features may be added in the mold that must be moved out of the way before the part could be ejected from the mold. 
     The foregoing description of embodiments of the invention comprises a number of elements, devices, circuits and/or assemblies that perform various functions as described. These elements, devices, circuits, and/or assemblies are exemplary implementations of means for performing their respectively described functions. 
     While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.