PHOTOVOLTAIC INSTALLATION

Abstract

To enable the economical and energy-efficient use of a PV system (1) with upright, in particular bifacial, PV modules (2) and especially to largely avoid shading of the PV modules (2), a very simple support structure (3) to manufacture and assemble is proposed, which is constructed by vertical posts (4) connected to each other at intersection points and horizontally running beams (5), so that right-angled mounting fields (6) can be provided for the individual PV modules (2), wherein the posts (4) and beams (5) can preferably each be formed in a material-saving manner by common profiles (12, 22) and wherein in particular a division of the posts (4) into two connectable sections (7), (8) significantly facilitates the assembly overall;Secondly, the invention proposes an electrical interconnection such that superimposed active surfaces (9, 9') can be operated at different electrical operating points, thus preferably forming separately operated electrical lines 21, which are preferably arranged horizontally. This further minimizes the effects of shading of PV modules 2 on the energy conversion efficiency of the PV system 1;

Description

[0001] The invention relates to a photovoltaic (PV) system with several bifacial photovoltaic modules arranged upright on a support structure. The invention further relates to a PV system with at least one bifacial PV module arranged upright on a support structure.

[0002] The invention also deals with the use of such PV systems for electricity generation in a specific configuration.

[0003] Conventional photovoltaic (PV) systems that use unifacial PV modules for electricity generation are often installed at an angle. The only active surface of each PV module, which can convert solar radiation into electrical energy, is typically oriented towards the south. Such systems have the disadvantage of delivering their peak power output at midday. This can strain the electricity grid, particularly during periods of oversupply of such electricity.

[0004] Therefore, for several years now, PV systems with modules that have active surfaces on both sides have been tested. These PV modules, known as bifacial modules, are positioned vertically so that both the front and back are illuminated by the sun. If the bifacial PV modules of such systems are oriented north-south, they can capture sunlight from east and west, especially in the early morning and late evening. This results in a power output complementary to that of conventional systems, with low output around midday but peak values ​​in the morning and evening. Such a daily power curve characteristic is advantageous in terms of ensuring a consistent power supply to the grid throughout the day. However, PV systems with bifacial modules can also be used effectively in orientations other than north-south.

[0005] Bifacial PV modules, unlike unifacial PV modules, present new technical challenges because the back side of the modules is also intended to be used for power generation. The support structures and installation concepts developed so far for unifacial PV modules are therefore only partially applicable, or would require complex and thus expensive modifications.

[0006] One object of the present invention is therefore to provide a photovoltaic system in which several bifacial PV modules can be mounted in a vertical arrangement and which meets the specific requirements of bifacial modules. For this purpose, a support structure is to be provided in particular that is not only cost-effective to manufacture, but also enables rapid and therefore inexpensive installation of the PV system. Furthermore, the support structure should exhibit sufficient stability under typical weather conditions.

[0007] The invention also aims to improve the efficiency of converting sunlight into electrical energy for PV systems.

[0008] To solve these problems, the features of claim 1 are provided according to the invention for a photovoltaic system. In particular, it is thus proposed according to the invention, to solve the problem in a photovoltaic system of the type mentioned at the outset, that the supporting structure has several posts which are attached to or in the ground, in particular anchored, wherein rails are attached to the posts, each connecting two adjacent posts, and wherein two posts and two rails define a substantially rectangular mounting field in which at least one PV module is arranged. Furthermore, it is proposed that the PV modules are attached to the rails, wherein retaining elements are provided for this purpose, which provide groove sections into which an edge of the respective PV module is inserted.

[0009] A mounting field according to the invention can therefore accommodate one or more PV modules, and further subdivisions of the mounting field, for example by means of additional crossbars and / or vertically extending intermediate posts, may also be provided. The mounting field according to the invention can be considered substantially rectangular, in particular, if it is suitable for accommodating a PV module with a rectangular outer contour. Therefore, according to the invention, it can be provided that two posts and two crossbars define a mounting field in which at least one PV module is arranged, wherein the edges of the posts and crossbars that are aligned with the PV modules and thus define the mounting field are preferably arranged at uniform intervals from the outer edges of the at least one PV module.

[0010] In most installation situations, it is advantageous if the multiple bifacial photovoltaic modules are arranged vertically on the supporting structure.

[0011] In other words, the invention provides a support structure in which posts and beams are connected to each other at preferably regular intervals and preferably at right angles, such that two posts and two beams define a rectangular mounting field into which a bifacial PV module is inserted in a vertical suspension. This allows the PV modules to collect sunlight from both sides in order to convert it into electrical energy.

[0012] According to the invention, it is advantageous for high rigidity of the supporting structure if at least individual beams are attached to posts on both sides by means of fasteners. In this context, a suitable fastening of the beams can be achieved in particular by screws, especially self-drilling screws or threaded screws, by rivets, pins, as well as by welding, bonding or by simple positive locking.

[0013] An advantage of this is that a PV system according to the invention, with the features of claim 1, can be manufactured cost-effectively and installed efficiently and therefore cost-effectively. At the same time, the supporting structure according to the invention ensures high stability, particularly against wind loads, as well as efficient utilization of the active areas of the bifacial modules.

[0014] According to the invention, the supporting structure can, for example, be anchored in the ground. This can be achieved, for example, by ground anchors, ground screws, driven piles, or concrete foundations, with additional bracing being provided. If anchoring in the ground is to be avoided, for example, when installing the PV system on landfill sites, the supporting structure can also be anchored according to the invention by weighting the posts against the ground. Furthermore, both the posts and the beams can be designed in the form of longitudinal profiles, for example, as extruded aluminum profiles, which enables particularly economical use of material and thus a lightweight supporting structure. According to the invention, the supporting structure can be made, for example, from C-, S-, U-, Σ-, or Ω-profiles, in particular from combinations of such profiles.For example, angled and / or rounded elements can be provided on the posts and / or beams to minimize shading of the PV modules. Another embodiment according to the invention provides for posts and / or beams made of hot- or cold-rolled steel, preferably with corrosion protection.

[0015] According to the invention, the problem can also be solved by further advantageous embodiments of the dependent claims.

[0016] For example, according to the invention, it is advantageous if, in the operating position of the PV system, the posts are oriented essentially vertically and / or the crossbeams essentially horizontally. Such an orientation of the posts and crossbeams ensures, in particular, that the edges of the posts and crossbeams, which define the individual mounting bays and are aligned with the PV modules, are preferably spaced evenly from the outer edges of rectangular PV modules of the PV system. This allows for economical material usage for the supporting structure and / or good space utilization for rectangular PV modules, which are typical on the market, since the distance between the posts and crossbeams and the PV modules can be kept as small as possible.Unlike conventional PV systems for unifacial PV modules, this design avoids having posts or beams running below or behind a PV module, which would result in undesirable shading of the PV modules.

[0017] In addition, a PV system according to the invention can, for example, be provided for several, in particular up to four, PV modules to be arranged one above the other in a vertical direction. By providing several vertically arranged rows of PV modules, the total usable active area can be increased without the need for additional posts. According to the invention, providing more than four vertically arranged PV modules has the disadvantage that the wind load increases considerably, so that the foundations for the posts must be designed to be significantly more complex and therefore more expensive. Therefore, the invention proposes limiting the number of vertically arranged modules to four. According to the invention, the optimum number of rows of vertically arranged PV modules lies between two and three.

[0018] According to the invention, it is further preferred if horizontally adjacent PV modules are arranged offset from one another in the vertical direction. This configuration, atypical for conventional systems, enables a particularly efficient design of the supporting structure. This is especially true when the vertical offset between horizontally adjacent PV modules is at least the height of a beam. Beams can thus be mounted vertically one above the other on the posts, which is advantageous for numerous configurations of the supporting structure according to the invention. In particular, the respective attachment points of horizontally adjacent beams on a post can thus be arranged vertically one above the other. This allows for the efficient use of flanges and lugs on the posts, as will be explained in more detail below.

[0019] To enable the most efficient installation of the PV system posts, the invention provides that the posts are divided into at least one fastening section connected to the ground and a holding section that can be connected to or is connected to the fastening section. The holding section extends above the fastening section. It is advantageous that the fastening section can initially be anchored in or against the ground independently of the holding section. This is particularly useful, for example, if the fastening section is to be anchored by driving it into the ground. For this purpose, the fastening section can be designed, in particular, as a driving profile, so that it has sufficient rigidity for driving.

[0020] According to the invention, both the holding section and the fastening section can be designed as longitudinal profiles, preferably made of metal. An advantage of this is that different profiles can be combined. For example, a C-, U-, or Σ-profile, which is suitable for driving into the ground, can be combined as the fastening section with an S- or Ω-profile, which are less suitable for driving into the ground, as the holding section of the post. Furthermore, the holding section can be designed to be thinner than the fastening section in order to save material. This can be achieved, for example, by selecting a different profile, particularly with different profile dimensions, or by reducing the material thickness.

[0021] After the mounting section has been anchored, the retaining section can be aligned with the mounting section and firmly connected to it, for example, by means of self-tapping screws that can be screwed into pre-drilled holes. According to the invention, it is preferred if corresponding contact surfaces are formed on both the mounting section and the retaining section. The two sections can abut and thus overlap at these contact surfaces. This provides a way to compensate for deviations in the height of the mounting section by aligning the retaining section with respect to the mounting section. For this purpose, the retaining section can be designed to be slidable along the longitudinal direction of the mounting section, particularly when its contact surface rests against the mounting section.

[0022] According to the invention, the overlap between the fastening and holding sections can be designed to be rotatable. This allows the two sections of a post to be rotated relative to each other when the corresponding contact surfaces are in contact. This can be achieved, for example, by designing the contact surface to be flat, so that the fastening and holding sections lie back-to-back in the assembled state. A rotatable design of the overlap enables rotation of the longitudinal axes of the two post sections relative to each other, thereby improving compensation for misalignments of the fastening section that can occur during its foundation installation.

[0023] According to the invention, it is further advantageous if the individual PV modules, and in particular their outer edges, are arranged at a distance from the posts and / or beams. This prevents shading of the active area of ​​the PV modules by the posts and / or beams. According to the invention, it is preferred if the spacing is chosen to be such that shading is excluded up to a maximum angle of incidence of 75°. This avoids excessive space requirements for the spacing, thus enabling efficient use of the area. Generally, according to the invention, it is preferred if the PV modules are mounted centrally with respect to the outer edges of the posts and / or beams. This minimizes shading on both sides of the bifacial PV modules.

[0024] The angle of incidence, as used here and in the following, is understood to be the angle that an incident ray of sunlight forms with a normal to an active surface of a PV module. Thus, perpendicular incidence of light onto the active surface of a PV module corresponds to an angle of incidence of 0°. Since the PV modules are arranged vertically, the angle of incidence can also be a lateral angle of incidence.

[0025] A highly efficient PV system can be achieved according to the invention if the active surfaces of the PV modules are arranged at a distance from the posts and / or beams. This largely prevents the posts or beams from shading the edge areas of the active surfaces of the PV modules when the light is at an angle, which would negatively affect the efficiency of the system.

[0026] According to the invention, it is particularly advantageous if the active surfaces of the PV modules are spaced away from the posts in such a way that shading of the active surface by the posts is prevented at least up to an angle of incidence of 20°, and more preferably at least up to an angle of incidence of 30°. Alternatively or additionally, it can be provided that the active surfaces of the PV modules are spaced away from the beams in such a way that shading of the active surface by the beams is prevented at least up to an angle of incidence of 25°, and more preferably at least up to an angle of incidence of 30° or even 40°.

[0027] According to the invention, an even more compact PV system can be achieved by arranging the active surfaces of the PV modules asymmetrically spaced from posts and / or beams on opposite sides. For example, individual PV modules can be spaced from the posts in such a way that, for northerly directions, shading of the active surface of the PV module is excluded at least up to an angle of incidence of 20°, preferably at least up to an angle of incidence of 30°, while for southerly directions, shading of the active surface of the PV module is excluded at least up to an angle of incidence of 45°, preferably at least up to an angle of incidence of 60°.

[0028] According to the invention, for horizontally extending beams, it is sufficient if the PV modules are only spaced apart from those beams that run above the PV module. This prevents shading of the active area by beams running above. In contrast, for modules arranged above a horizontally extending beam, there is no risk of shading by the beam running below the module, since the direct sunlight strikes the active area obliquely from above. As a result, according to the invention, the active area of ​​a PV module can be positioned close to a horizontally extending beam to minimize the vertical space requirement of the PV system.

[0029] If the PV system is to be installed in particularly windy locations, the invention provides for the PV modules to be pivotally suspended from the support structure around an axis of rotation. It is advantageous if the axis of rotation runs approximately parallel to the crossbeams, as this ensures pivotability with a compact mounting area. Pivoting the PV modules around an axis of rotation can be achieved, for example, by suspending them only from the upper crossbeams of the support structure. Due to this pivotability, the PV modules can move out of the plane formed by the posts in strong winds. The resulting gaps in the mounting areas allow the wind to pass through almost unimpeded, thus significantly reducing the wind load acting on the support structure.The advantage here is that the supporting structure as a whole needs to be less stable, so that, for example, the posts can be made less rigid and thus overall material costs can be saved.

[0030] To enable the simplest possible installation of the PV system, the invention provides that the posts are equipped with mounting surfaces to which a corresponding crossbar can be attached across its entire surface. By ensuring that the crossbar rests against a mounting surface, forces and moments introduced by the crossbar can be effectively absorbed by the post.

[0031] According to the invention, the retaining surfaces can be designed particularly simply as flanges on a profile and / or as tabs on an opening, for example, incorporated into an outer surface of a profile. It can also be provided that retaining surfaces on one side of a post are designed as flanges and on the other side as tabs. Tabs or flanges are thus considered alternatives according to the invention, whereby, according to the invention, it is preferred for both tabs and flanges if they project perpendicularly from the posts and / or extend in the direction of a plane, preferably laterally offset from it, formed by the PV modules. Furthermore, bores, slots, or the like can also be provided on tabs and / or flanges to facilitate the fastening of the bars by means of screws or the like.

[0032] According to the invention, a flange serving as a holding surface can extend, in particular, along an entire holding section of a post; the flange can thus be part of a profile; however, it can also be subsequently attached to a post, for example by welding. When using profiles that only have simple flanges at their ends, for example an S-profile, additional angle brackets that can be screwed onto a profile can be provided according to the invention. This allows a closed, circumferential force flow to be formed when a bar is attached to a simple flange in conjunction with an angle bracket, thus increasing the stiffness of the structure. In addition, flanges on posts can also be provided according to the invention solely to increase the bending stiffness of the posts.

[0033] According to the invention, the shape of a tab can be determined by the shape of the associated opening in a profile, for example by producing the openings and associated tabs cost-effectively on the post using processes such as punching or laser cutting in conjunction with bending or forming. In this case, a pair of tabs can also be formed from one opening, arranged on both sides of the opening to allow a bolt to be gripped from both sides.

[0034] The robustness and stiffness of the supporting structure can be further increased according to the invention if the retaining surfaces are formed in pairs. This is because a pair of retaining surfaces can grip a beam inserted between them on both sides, thus further improving the dissipation of forces. To facilitate gripping a beam on both sides by the retaining surfaces, it is also advantageous if the beams are narrower than the posts, in particular narrower than the distance between pairs of retaining surfaces.

[0035] Alternatively or additionally, it is also possible to attach the rails to the posts using angle brackets. According to the invention, angle brackets are preferred which have holding surfaces on both sides of the rail to be attached, which can be connected to a post over a flat surface.

[0036] Another possible embodiment of the invention provides that through-holes are formed in the posts to accommodate a bolt or its end. The design of through-holes has the advantage that tilting of the posts relative to one another and the associated fluctuations in the distances between the posts can be easily compensated for by inserting the bolts more or less deeply into the through-holes.

[0037] It is understood that for easy assembly, it is advantageous if the through-hole is designed to be somewhat larger than the bolt it is intended to accommodate. However, according to the invention, it can be provided that the through-hole has a vertical dimension of at least 1.25 times, preferably at least 1.5 times, the height of a bolt. This creates a way to at least partially compensate for different post heights, for example in undulating terrain, by mounting the bolts at different heights.

[0038] In contrast to through-holes formed laterally on the outer surfaces of the posts using attached angle brackets, through-holes offer the advantage that, according to the invention, they can be arranged centrally with respect to the post. This makes it particularly easy to ensure that the PV modules are positioned centrally with respect to the post and / or rail. Such an arrangement is preferred according to the invention because of minimized shading on both sides of a PV module.

[0039] When using through-holes, it is particularly advantageous if at least the retaining section of the post is designed in the form of an omega profile. This is because, with an omega profile, two horizontally adjacent rails can be gripped on both sides by the two open ends of the omega profile, which can be formed by a pair of parallel flanges running along the profile. This creates a closed force flow within the omega profile. Individual rails can be guided through through-holes formed in the side faces of the omega profile. In this configuration, rails running to the left and right of a post designed as an omega profile can be attached to a pair of flanges running along one side of the post. This results in a particularly easy-to-assemble yet robust design for the supporting structure.

[0040] A similarly robust connection between post and rail using through-holes can be achieved according to the invention if at least the holding section of the post is designed in the form of a C- or U-profile. In this case, through-holes can be formed on the side faces of the respective profile, which have bent-up tabs that in turn provide holding surfaces for mounting rails.

[0041] If two rails running to the left and right of a post are to be mounted on a tab, it is advantageous if the height of the tab is more than 1.25 times the height of one rail, preferably at least 1.5 times the height of one rail. With this design, a tab, or a pair of tabs, of a through-hole is thus high enough to hold two rails. An additionally taller through-hole can nevertheless be useful according to the invention to allow for improved compensation of the mounting height of rails.

[0042] In one embodiment of the invention, through-holes can have one or more tabs, as previously described, which provide holding surfaces for mounting a bar, preferably two bars. This results in a variety of configurations, also in conjunction with omega profiles. In contrast to separately attached angle brackets, tabs offer the advantage of reduced assembly effort, since they do not need to be attached to the profiles like angle brackets. Furthermore, bent-up tabs are generally rotationally fixed to a vertical surface of a profile, thus easily achieving high torsional rigidity of the supporting structure.

[0043] In general, and particularly in all previously described configurations of through-holes, it can be provided that individual through-holes have a height of at least twice, and especially at least three times, that of a bolt. This configuration allows one bolt, or in particular two bolts, to be placed in a through-hole, whereby, due to the larger size of the through-hole, the mounting height of the bolt(s) relative to the through-hole can be variable, and thus can be adjusted, especially during installation. This allows for height compensation, which is particularly advantageous on uneven ground.

[0044] As an alternative to receiving at least two bolts in a through-hole, a further embodiment of the invention provides that only one bolt is placed in a through-hole, while a further bolt is mounted on a side of the post opposite the through-hole, without a through-hole, by means of retaining surfaces formed on the post. In this embodiment, it can be provided, in particular, that the bolt guided through the through-hole is mounted on the same retaining surface as the further bolt on the side of the post opposite the through-hole. In other words, according to one embodiment of the invention, it can be provided, in particular, that a bolt inserted through a through-hole and a further bolt are attached to a retaining surface.

[0045] Another embodiment of the invention provides that the posts have a profile with a C-shaped or U-shaped base, at least in the holding section. Additional holding surfaces can be formed as flanges at the ends of the profile. The flanges can either be formed during the manufacturing of the profile or subsequently attached to the profile.

[0046] According to yet another embodiment of the invention, the posts may have a profile with a Z-shaped or S-shaped basic form, at least in the holding section, with additional holding surfaces formed as flanges at the ends of the profile. S-shaped profiles are also known commercially as "Z-plus" profiles. "Additional holding surfaces / flanges" here, as with the C- or U-shaped profiles previously, is to be understood as meaning that the basic form of the profiles is already present without the flanges, even if these are created during the manufacturing of the profile.

[0047] For particularly simple yet robust mounting of the PV modules, it is preferred according to the invention if the PV modules are attached to the mounting rails. If modules are mounted in landscape / portrait format, the modules are therefore held in place along their longer / shorter sides. Special holding elements can be provided for this purpose according to the invention. Preferably, these holding elements provide groove sections into which an edge of the respective PV module is inserted or can be inserted, preferably without a force-fit connection. The groove sections can be lined with a plastic or elastic material, preferably EPDM, to protect the PV modules from damage. Furthermore, it can be additionally provided that the PV modules are bonded to the holding elements to prevent the PV modules from slipping in the groove sections.

[0048] According to the invention, the retaining elements can be manufactured, for example, as cold-formed steel parts, preferably made of corrosion-resistant steel and / or with corrosion protection, or made of plastic or light metals such as aluminum, and in particular have a rubber coating. The retaining elements can also be manufactured in the form of profiles or as injection-molded or die-cast parts.

[0049] According to the invention, the PV modules are preferably held on both sides by the respective retaining element in the area of ​​the groove sections, so that a secure holding of the PV modules can be ensured.

[0050] It is understood that retaining elements as described above can also be used to attach PV modules to the posts in an analogous application of the invention.

[0051] Particularly preferred are two opposing groove sections formed on each of the retaining elements. Thus, a single retaining element can hold two opposing PV modules. It is advantageous if the two groove sections run in a common plane. Additionally or alternatively, it can also be provided that the two groove sections are arranged centrally with respect to the lateral outer surfaces of the retaining element. Such configurations significantly facilitate the central positioning of all PV elements with respect to posts and / or rails, which is preferred according to the invention.

[0052] Furthermore, it can also be provided that the retaining elements each have a cross-sectional reduction, preferably at right angles. At the point where the cross-section changes, a stop can thus be formed on the retaining element. This allows the retaining element to be inserted, or to be inserted, into an opening formed on a bolt up to a defined insertion depth. Accordingly, the invention can provide that the bolts, in particular those arranged centrally, have through-holes corresponding to the retaining elements. These through-holes on the bolts can be designed in such a way as to prevent the retaining elements from slipping in the longitudinal direction of the bolt.

[0053] A key advantage of this design is that, for robust positioning of the PV modules, it is sufficient to attach the retaining element to the mounting bar in the area of ​​an upper groove, for example, by means of a screw; additional fastening in the area of ​​the second, lower groove is therefore unnecessary. This not only saves assembly effort, but also allows the retaining elements to be made narrower in the lower area surrounding a lower retaining groove than in the upper area, which is advantageous for preventing shading of the PV modules.

[0054] For a position-secure and tilt-free mounting of the retaining elements, it is also advantageous according to the invention if a contact surface is formed on the retaining element with which the retaining element lies flat against the bar.

[0055] A further optimization of the retaining elements according to the invention provides that they have a chamfer on an underside, so that shading of a PV module that is inserted into a lower groove of the retaining element can be avoided.

[0056] As an alternative or supplementary embodiment to separate retaining elements, the invention provides for groove sections to be formed on the bars into which a respective PV module can be inserted. These grooves can, for example, be formed only on one upper side of a bar and / or, in particular, extend over the entire length of a bar. An advantage of this is that the PV modules can be inserted directly into the grooves of the bars during assembly, thus reducing the number of retaining elements required. This approach can reduce assembly effort and therefore save costs.

[0057] Similar to the mounting elements, the bars can also be designed with a chamfer on their underside. This ensures that even at the edges of the active area of ​​the PV module, large angles of incidence can be maintained without shading from the respective bar.

[0058] The invention further recognizes that it can be advantageous to design the supporting structure in such a way that the cultivation of the area on which the PV system is to be installed, particularly agricultural cultivation, remains possible, especially of the open spaces between individual rows. For this purpose, the invention provides that a space is maintained between the soil and the lowest beam of the supporting structure. According to the invention, this space can have a height of at least 50 cm, preferably at least 60 cm, and particularly preferably at least 1 m. It is understood that the space is thus interrupted only by the necessary posts.

[0059] When installing PV modules in rows, it can be provided in particular that the rows of the PV system are spaced apart in such a way that there is a management space between the rows with a width of at least 6 meters, at least 8 meters or at least 10 meters.

[0060] For the most efficient use of space, and in particular for maximum energy production per unit area, it can be advantageous according to the invention if the PV modules and the supporting structure essentially form a single plane. Accordingly, the posts can be positioned along a substantially straight line. Above a certain minimum width of the installation area, the PV modules can also be arranged in several rows. It is advantageous if these rows are spaced apart from each other, preferably at uniform intervals. According to the invention, depending on the height of a row of the PV system, a minimum distance to a neighboring row in the direction of the sun can be selected such that shading of the active areas of the PV modules by the neighboring row is largely prevented. Rows of different heights, i.e., with a different number of PV modules stacked on top of each other, can also be provided.

[0061] In a particularly advantageous embodiment of the invention, the PV modules can be oriented essentially in a north-south direction. With a north-south orientation, the surface normals of the two active sides of a bifacial PV module are oriented east and west, respectively. According to the invention, angular deviations of + / -30° are permissible, which is why the orientation is described as "essentially" running in a north-south direction. Such configurations allow the PV system to achieve a current-time curve characteristic as described above, which exhibits no peak power around midday. However, PV systems according to the invention can be advantageously used in a variety of other orientations with respect to the cardinal direction.

[0062] According to the invention, the area utilization of the PV system can be optimized with acceptable losses in energy conversion efficiency if the distance between two rows is at least three times, preferably at least four times, and most preferably at least five times, the maximum height of an active area of ​​the PV system. This largely prevents shading of PV modules by an adjacent row, particularly in the morning and evening, depending on the geographical latitude of the PV system's installation site. The maximum height of an active area of ​​the PV system can, for example, be defined by the vertical distance between the highest and lowest points within the active areas of a row of the PV system (see also the figure description).

[0063] Shading is known to be detrimental because the individual cells of a PV module are typically connected in series to form cell strings, meaning that the least illuminated cell limits the actual current flow. While bypass diodes are known in the art and are typically included in PV modules to minimize the effects of partial shading of the active area, relying solely on bypass diodes to minimize these effects has significant drawbacks. For example, a considerable amount of heat is generated when a bypass diode switches on to electrically bridge a shaded area of ​​the active surface.However, this approach is unacceptable, especially for PV systems like the one described in the invention, where shading is to be expected daily, as frequent heat generation can negatively impact the lifespan of the PV modules. A further disadvantage is that many inverters on the market, despite having bypass diodes, set an operating point that is unfavorable for the PV module, resulting in further power losses in the PV modules connected to the affected inverter.

[0064] To increase the efficiency of energy conversion in a PV system, the features of the second independent claim are provided as an alternative. This claim relates to a PV system with at least one bifacial PV module. In particular, for a photovoltaic system with at least one bifacial PV module, which can be further developed by the previously described configurations of the support structure, the invention proposes, to solve the aforementioned problem, that the electrical interconnection of active surfaces of the PV system, in particular all active surfaces, is selected such that active surfaces of the electrical interconnection located at different heights can be operated at different electrical operating points. In particular, it can be provided that upper (i.e., top-arranged) active surfaces are electrically connected in parallel to lower (i.e., bottom-arranged) active surfaces.Alternatively or additionally, upper active surfaces can be serially connected and / or lower active surfaces can be serially connected.

[0065] According to a further embodiment of the invention, such a circuit can be connected using an electrical module-free return path, for example by means of a cable, so that no PV modules interrupt the return path. Such an electrical module-free return path can, in particular, be implemented corresponding to PV modules connected in series. In conventional PV systems with unifacial PV modules, such return paths have so far been avoided for both cost and technical reasons. However, the invention recognizes that the significant influence of shading on PV systems with vertically oriented PV modules may necessitate such return paths if optimal electrical connection of the PV modules is to be ensured.

[0066] The invention has also recognized that when using upright bifacial PV modules for a PV system, it offers significant advantages if all active surfaces located at different heights can be operated at different operating points, as long as this rule is only deviated from in peripheral areas of the PV system.

[0067] This design means that currents flowing through active surfaces of one or more PV modules arranged at different heights within the PV system can vary. This design thus prevents, for example, shading of a lower active surface from limiting power production in an upper active surface, as would occur if the upper and lower active surfaces of one or more PV modules were electrically connected in series.

[0068] For some time now, rectangular bifacial PV modules have been available on the market, featuring two electrically separated active surfaces, each typically containing multiple cell strings, with the electrical separation running parallel to the shorter side of the module. The invention proposes to install such bifacial PV modules with electrically separated active surfaces in a vertical orientation, thus forming upper and lower active surfaces as defined by the invention.

[0069] The statement that the active areas are electrically separated from each other can, in the context of the invention, be understood in particular to mean that these active areas are not connected to each other in a series circuit; however, an electrical parallel connection of the active areas, even within the PV module, may be provided.

[0070] The invention further proposes operating the upper active surfaces of such bifacial PV modules in parallel with the lower active surfaces, so that the upper active surfaces can operate at an electrical operating point that differs from that of the lower active surfaces. If even one of the lower active surfaces is shaded, the current flow through the upper active surface(s) remains unaffected, since a current path parallel to the shaded lower active surface exists through the upper active surface(s). An electrical operating point within the meaning of the invention can therefore be defined, in particular, by an electric current flowing through the corresponding active surface.

[0071] It is understood that, for the purposes of the invention, active surfaces, and in particular PV modules as a whole, arranged at approximately the same height, can be connected in series. If active surfaces of the PV system, arranged at approximately the same height, are connected in series, this can be referred to as an electrical line according to the invention.

[0072] One embodiment of the invention proposes creating electrically separated electrical lines by connecting active surfaces in series, arranging these electrical lines at different heights, and preferably operating the electrical lines in parallel. This allows the flow currents in the individual electrical lines to vary, which is equivalent to saying that active surfaces in different electrical lines can be operated at different operating points, i.e., in particular at different currents.

[0073] One possible realization of a PV system according to the second independent claim with an upper and a lower active area that can be operated at different operating points thus consists in the series connection of PV modules to, preferably arranged one above the other, electrical rows and the operation of these electrical rows in parallel connection, for example at a common inverter input or at different inverter inputs.

[0074] Utilizing electrically separated active areas of one or more PV modules by operating them in separate electrical rows can be particularly advantageous during the shoulder hours of the day. This is because, if the PV module is partially shaded due to a low sun angle, typically only the lower electrical row is less effective, while the upper electrical row, which is still fully irradiated, can operate normally. In contrast, if PV modules with electrically separated active areas were installed horizontally as described above, the entire module's efficiency would be reduced, since both active areas would be partially shaded.

[0075] Since, according to the invention, electrical arrays arranged one above the other can be operated in parallel, it is possible to avoid the shading of one array and the associated limitation of the current flow in that array affecting an adjacent (typically above) array. An electrical array according to the invention can, for example, already be formed by one of two electrically separated, active surfaces of a PV module.

[0076] According to a further embodiment of the invention, high output power of the PV system can be achieved particularly cost-effectively if an electrical line, as described above, is formed by series connection of active surfaces, in particular of at least two bifacial PV modules. As explained above, the electrical division into electrical lines allows the current flows through different electrical lines to be independent of each other / to differ from each other.

[0077] An electrical line can thus be formed, in particular, by the active surfaces of horizontally adjacent PV modules. For this purpose, it is advantageous, according to the invention, if preferably such active surfaces of PV modules are electrically connected in series and are arranged at approximately the same height. Within a PV module, however, it can be advantageous if the active surfaces are electrically connected in parallel, particularly if they are arranged vertically one above the other.

[0078] In accordance with the invention, it is particularly advantageous if each electrical line is electrically connected to an inverter input. According to the invention, individual lines can be connected to inverter inputs of different inverters or to an inverter input of a common inverter.

[0079] The invention thus recognizes that an electrical line can be formed across several bifacial PV modules, so that, in particular, not each bifacial PV module needs to be connected to its own inverter, which can save costs. In this context, a line can be shorter than a row of posts with PV modules mounted between them. This is because, when active surfaces are connected in series, the electrical voltages generated in them add up, so the number of active surfaces that can be connected in series typically has to be limited.

[0080] Without limiting the invention or contradicting it, it can, for example, be provided according to the invention in the edge regions of a series to connect superimposed active surfaces in series, either within a single PV module or across several PV modules. This ensures efficient and cost-effective power generation even in edge regions, particularly at sufficiently high voltages. A partial reduction in the efficiency of the entire PV system due to shading of parts of the edge regions is deliberately accepted.

[0081] According to a further embodiment of the invention, it is considered advantageous if the PV modules, preferably each PV module, have at least two electrically separated active surfaces, each assigned to different electrical lines. This ensures that even with partial shading of a PV module, high efficiency in the conversion of radiation incident on the PV module into electrical energy can be maintained for the entire PV system.

[0082] Finally, according to the invention, it can also be provided that a PV system with several, in particular two, electrical rows designed according to the invention, with features as described above and / or according to one or more of claims 16 and 17, has a supporting structure with features according to the invention as set out above and / or according to one or more of claims 1 to 15.

[0083] To solve the aforementioned problem, a specific use of a PV system according to the invention, as described above, is also provided. In particular, it is thus proposed according to the invention that a PV system according to the invention, especially as described above and / or according to one of the claims directed to a photovoltaic system, is used such that the PV modules are oriented approximately in a north-south direction during power generation. In this context, angular deviations of + / -30° are permitted according to the invention, which is why the orientation is described as "approximately" in a north-south direction. With a north-south orientation of a PV module, the surface normals of the two active sides of a bifacial PV module are oriented east and west, respectively.This specific use makes it possible to achieve a daily power curve characteristic as described above with a PV system according to the invention, which has no peak power around noon.

[0084] The invention will now be described in more detail using exemplary embodiments, but is not limited to these exemplary embodiments.

[0085] Further embodiments result from combining the features of one or more claims with each other and / or with one or more features of the respective embodiment. In particular, embodiments of the invention can thus be derived from the following description of a preferred embodiment in conjunction with the general description, the claims, and the drawings.

[0086] It shows: Figure 1 a three-dimensional view of a photovoltaic system according to the invention, Figure 2 a detailed view of a row of posts of the same PV system, Figure 3 a post according to the invention designed by means of a C-profile with two mounted bars, Figure 4 a post according to the invention designed by means of an Omega profile with two mounted bars, Figure 5 a bar according to the invention with two opposing groove sections for receiving two PV modules, Figure 6 a cross-section through a holding element according to the invention which is inserted into a bar formed by a U-profile, Figure 7 a perspective view of the holding element made of Figure 6, inserted into the U-shaped bar, Figure 8 a top view of a post and PV modules spaced asymmetrically in the north and south directions to it in the manner of the invention, as well as their active surfaces, Figure 9 a side cross-sectional view of a horizontally extending bar and PV modules arranged above and below it and their active surfaces, Figure 10 a side view of a PV system according to the invention with two rows of posts spaced apart, Figure 11 an electrical connection of PV modules of a PV system according to the invention, Figure 12 another electrical connection of PV modules of a PV system according to the invention, Figure 13 a cross-sectional view of a suspension of PV modules on a support structure of a PV system according to the invention,Figure 14 shows a cross-sectional view of another suspension of PV modules according to the invention on a supporting structure according to the invention for a PV system.

[0087] In the following description of various embodiments of the invention, elements that are functionally identical are given the same reference numbers even if they differ in design or shape.

[0088] The Figure 1 Figure 1 shows a photovoltaic (PV) system, designated as a whole by 1, with several bifacial PV modules 2 arranged upright on a support structure 3. The support structure 3 is formed by several posts 4 arranged in a row. More precisely, each post 4 is divided into a fastening section 7 and an associated retaining section 8. As indicated by the horizontal plane, which illustrates the ground surface, the support structure 3 is anchored in the ground by means of the fastening sections 7.

[0089] As the Figure 1 As shown, several bars 5 run between the posts 4, essentially in a horizontal direction. Since the posts 4 are mounted essentially vertically, each pair of adjacent posts 4 and two adjacent bars 5 defines an essentially rectangular mounting field 6. In the Figure 1 In the illustrated embodiment, a PV module 2 is arranged vertically in each of these rectangular mounting fields 6. The upright arrangement of the PV modules 2, which have active surfaces 9 on both sides, makes it possible to efficiently capture sunlight from west and east directions and convert it into electricity by means of the PV system.

[0090] As shown in the detailed view of PV system 1 in Figure 2 As shown, several PV modules (2), specifically exactly two, are arranged vertically, one above the other. In addition, in Figure 2It is clearly visible that, for example, the uppermost bars 5 are arranged offset from each other in the vertical direction. Since the PV modules 2 are attached to the bars 5 by means of retaining elements 15, horizontally adjacent PV modules 2 are also arranged offset from each other in the vertical direction. This configuration is preferred according to the invention because it allows for easy compensation of different terrain contours.

[0091] As with regard to Figure 2As can be clearly seen, the fastening sections 7 and the holding sections 8, each formed by C-profiles, lie back-to-back against each other and thus overlap in an overlap area. According to the invention, it is preferred if the overlap area is located above ground level, as this facilitates the assembly of the holding section 8 onto the fastening section 7 and also allows the fastening section 7 to be anchored in the ground independently of the holding section 8, e.g., by driving it in.

[0092] The Figure 3 Figure 1 shows an embodiment according to the invention of a connection between a post 4, more precisely its upper retaining section 8, and two horizontally extending bars 5. While the bars 5 are each formed by a U-profile 22, the retaining section 8 of the post 4 is formed by a C-shaped profile 12.

[0093] To attach the two bars 5, a bracket is inserted into the post 4. Figure 3An opening 14, designed as a through-hole, is provided through which the bolts 5 are passed or inserted. The opening 14 itself is created by punching a hole in the C-profile 12 of the post 4. The two bolts 5 can be easily connected by a punching operation. Figure 3 The tabs 13 shown are generated, which, according to the invention, serve as holding surfaces 10. For example, the two latches 5 can be attached to the two tabs 13 very easily and at variable heights by means of screws with self-tapping threads and correspondingly drilled holes.

[0094] The Figure 4 Figure 1 shows an alternative embodiment of the retaining surfaces 10 according to the invention. For this purpose, the post 4, more precisely its upper retaining section 8, is designed by means of an omega profile 12. At its two free ends, the omega profile 12 has two flanges 11 which, unlike the tabs 13 in Figure 3, extend along the entire length of the omega profile 12 and can advantageously be used as retaining surfaces 10 according to the invention. The left rail 5 is simply inserted into the omega profile 12, while the right rail 5 is guided through a through-hole 14 formed in a side face of the post 4. As can be clearly seen, both rails 5 can be attached one above the other to the paired retaining surfaces 10 of the omega profile 12. The paired design of the retaining surfaces 10, each on both side faces of a rail 5, allows for a particularly stable connection and thus a particularly stable supporting structure 3. Figure 4 The paired retaining surfaces 10 grip the bars 5 on both sides.

[0095] Both from Figure 3 as well as from Figure 4The advantage of a further embodiment of the invention becomes apparent when the rails 5 are designed to be narrower than the posts 4. This design greatly facilitates the insertion of the rails 5 through the through-holes 14 in the posts 4 and simultaneously secures them on both sides, particularly from the outside, by the retaining surfaces 10 formed on the posts 4. Figure 4 , are caught.

[0096] According to the invention, either two latches can be placed in a through-hole 14, as is the case in Figure 3 illustrated, or simply a bar, as illustrated in the example of the Figure 4 shows how Figure 4As shown, a further bar 5 adjacent to a first bar 5 placed in a through-hole 14 can thus be mounted on a side of the post 4 opposite the through-hole 14, without using a through-hole 14, namely by means of retaining surfaces 10 formed on the post, which are Figure 4 formed by the flanges 11. Such a design is very useful, for example, to compensate for different heights in uneven terrain.

[0097] For example, the one in Figure 3 The illustrated embodiment can optionally be interpreted as meaning that the post 4, or at least its retaining section 8, is formed by a profile 12 with a C-shaped or U-shaped base, wherein in the case of the U-shape the free ends of the profile 12 would be considered flanges 11. However, flanges 11, which are intended to serve as retaining surfaces 10, are preferred according to the invention as shown in Figure 4designed, i.e., the flanges 11 preferably run in the direction of the bars 5. This design allows the bars 5 to bear against each other in a flat surface. The in Figure 4 The Omega profile 12 of the post 4 shown can also be understood as a profile 12 with a C-shaped basic form, wherein the holding surfaces 10 shown are designed as flanges 11 at the ends of this profile 12.

[0098] As already mentioned in the Figure 2 As indicated, according to the invention the PV modules 2 are preferably attached to the bars 5, wherein for this purpose the in Figure 2 The holding elements shown (15) may be provided.

[0099] The Figure 5 Figure 5 shows an alternative embodiment according to the invention, in which groove sections 16 are provided on the bars for receiving and holding the PV modules 2. As shown in Figure 5. Figure 5As shown, according to the invention it is generally preferred if the groove sections 16 are opposite each other and / or lie in a common plane. This design allows the PV modules 2 to be aligned centrally with respect to the supporting structure 3. This is clearly visible in Figure 5 The chamfers 24 according to the invention are also located on the underside of the bar 5. These chamfers 24 minimize the shading of the lower PV module 2 by the bar 5.

[0100] Figure 6Figure 1 shows a detailed cross-sectional view through a retaining element 15 according to the invention. The retaining element 15 is inserted into a through-hole 23 formed on the underside of the bar 5, which is formed by a U-shaped profile 22. The retaining element 15 has a contact surface 18 that allows it to lie flat against the inside of the bar 5. The cross-sectional reduction 17, located at the level of the contact surface 18, allows the retaining element 15 to be inserted into the through-hole 23 to a defined insertion depth. This ensures, among other things, that the active surfaces 9 of the two PV modules 2 can be mounted at a defined distance from the bar 5, thus effectively preventing shading.

[0101] How good in Figure 6As can be seen, the PV modules 2 are inserted with their edges into the two opposing groove sections 16 of the retaining element 15. The insertion depth is chosen precisely so that the active surfaces 9 of the PV modules 2 are not covered or shaded by the retaining element 15 and / or the bar 5 up to a certain angle of incidence.

[0102] The features of the retaining elements 15 according to the invention, as just explained, are also clearly illustrated in the perspective view of the Figure 7 Illustrated. In particular, it is shown that Figure 7 It is evident that the retaining elements 15 preferably grip the PV modules 2 on both sides to ensure secure mounting. For this purpose, it is sufficient if the retaining elements 15 grip the PV modules on both sides only along a specific edge section, as shown in Figure 7 depicted.

[0103] The Figures 8 and 9This illustrates another key aspect of the present invention, namely, arranging the active surfaces 9 of the PV modules 2 at a distance from the posts 4 and / or beams 5. As shown in the top view of the post 4 in Figure 8 As shown, the active surfaces 9 of the two PV modules 2 arranged to the left and right of the post 4 are spaced from the post 4 in such a way that sunlight can reach the active surface 9 up to a certain angle of incidence without being shaded by the post 4. The angle of incidence corresponds to Figure 8 precisely the angle that the two depicted sun rays each form with the normal (running horizontally in Figure 8 ) of the relevant active area 9.

[0104] If one examines the two opposing sides of the two PV modules 2 more closely, it becomes apparent that the active surfaces 9 to the left and right of the post are not equidistant from the post 4. Rather, they are arranged asymmetrically. Due to the slightly greater distance of the active surface 9 of the in Figure 8 The arrangement of the PV module 2 above ensures that shading of the active area 9 by sunlight from southern directions is prevented for larger angles of incidence than is the case for the area in Figure 8 The PV module 2 arranged below is positioned for sunlight from northern directions. In other words, at the southern edge of a PV module 2, the distance between the PV module 2, more precisely its active area 9, and the post 4 is chosen to be slightly greater than at its northern edge, as is the case with the two PV modules 2 in Figure 8 illustrate.

[0105] The Figure 9In contrast, it shows how, by spacing the active surfaces 9 of the two illustrated PV modules 2 from the transverse bar 5 according to the invention, shading of the active surfaces 9 can be prevented. Since the Figure 9 The figure represents a cross-section through a horizontally extending beam 5. The depicted sunbeam strikes the lower PV module 2 obliquely from above and usually laterally. Due to the distance between the active surface 9 of the lower PV module 2 and the beam 5, as shown in Figure 9 The diagram shows a maximum angle of incidence, up to which sunlight can strike the active surface 9 without shading. Figure 9 This angle of incidence would correspond exactly to the angle formed by the projection onto the vertically running cutting plane of the Figure 9 The depicted incident sunbeam with the plumb line onto the active surface 9 (running horizontally in Figure 9) includes. It is therefore understood that the actual angle of incidence between the sunbeam and the normal can usually be larger than the angle formed by the (in Figure 9 (illustrated) projection of this ray in the plane of intersection with the normal.

[0106] In the rare event that in Figure 9 If the PV modules shown had their active surfaces pointing directly towards the sun, this would correspond to the one in Figure 9 The angle of incidence illustrated by the sunbeam corresponds to the sun's position, i.e., its height above the horizon, measured in degrees. However, sunlight typically strikes the PV modules obliquely from the side, so the sun's position and the angle of incidence differ. The two in Figure 8 The depicted sunbeams strike the PV modules 2 obliquely from the side, with projections of these rays into the horizontally running section plane of the Figure 8are shown.

[0107] Even in the Figure 9 In the illustrated embodiment, the PV modules could be spaced asymmetrically from the beam 5 according to the invention. For example, it would be advantageous according to the invention to move the upper PV module 2, more precisely its active surface 9, closer to the beam 5. This would reduce the maximum height of the supporting structure 3 and thus the wind load; furthermore, it would prevent the upper active surface 9 from being shaded by the beam 5 below, since sunlight always strikes the PV modules 2 obliquely from above. According to the invention, the upper PV module 2 could therefore be positioned close to the beam 5 until the active surface 9 is just barely not covered by the beam 5.

[0108] The Figure 10Finally, further embodiments of the photovoltaic system 1 according to the invention are explained, in particular the spacing of the rows 20 of the PV system 1 according to the invention. As already described in the Figures 1 and 2 As illustrated, the PV modules 2 can, according to the invention, essentially form a single plane with the supporting structure 3. For efficient use of the area, the PV modules 2 are arranged as shown in the illustration. Figure 10 shown, arranged in spaced rows 20. The PV modules 2 of a row 20 thus also essentially form a plane, whereby this plane can be oriented in a north-south direction, as shown in Figure 10 This is the case. Thus, for example, with a sunbeam coming from the west (from the left into Figure 10 ) the in Figure 10The situation shown occurs, in which a section of a row 20 (here the lower PV modules of the right row 20) is shaded by an adjacent row 20 (here the left row 20).

[0109] As seen through the two sunbeams in Figure 10 As indicated, the shading increases the lower the sun's angle. Therefore, a situation like the one described in... Figure 10 The embodiment shown is preferred, in which the distance B between the two rows 20 is more than three times the maximum height of an active area 9 of the PV system 1. This maximum height corresponds to Figure 10 especially the vertical distance A, which defines the distance between a highest and a lowest point, each within the active areas 9 of the left row 20. Due to the large horizontal distance B chosen according to the invention between the two rows 20, the upper sunbeam is thus positioned as if in Figure 10shows that even with a low sun angle, only a portion of the right row 20 is shaded, so that at least the upper active surfaces 9 of the right row 20 are visible. Figure 10 can continue to be used for electricity production.

[0110] A further advantage of spacing the rows 20 of the PV system 1 lies in the cultivation space 19 that arises between the rows, as this can be used, for example, for agricultural purposes. The invention provides, in particular, for the space 19 created between the rows. Figure 10 to make the management space 19, designated with a width B, usable by maintaining a free space 26 in each row between the posts 4 and between the lowest beam 5 of the supporting structure 3 and the ground surface. This ensures that the PV modules 2 are arranged at least at a height C above the ground (see figure). Figure 10Firstly, damage to the PV system from rockfall during agricultural use of the open space 19 can be avoided. Secondly, this design largely prevents the lower active areas 9 of the PV system from being shaded by vegetation or plantings in the open space 19. The open space 26 thus creates the necessary conditions for the agricultural use of the open space 19 without any significant loss of electricity production.

[0111] Based on the Figure 10 The advantages of a division of the PV system into superimposed electrical rows 21 according to the invention can also be understood. This is because the lower row 21 of the right row 20 is in Figure 10 electrically from the top row 21 of the right row 20 in Figure 10Since the lower row 21 is separate, i.e., each is assigned to a separate inverter input, the shading of the lower row 21 cannot affect the current produced by the upper row 21. Similarly, in Figure 10 The effect of partial shading of the upper PV module 2 of the right row 20 can be minimized according to the invention by the fact that this PV module 2 has two horizontally extending and superimposed electrical lines, formed for example by two electrically separated active surfaces 9 within the PV module 2.

[0112] The Figures 11 and 12 The inventive electrical connections of upper and lower active surfaces 9 of a PV system 1 are shown, respectively, in the upper and lower halves of the drawing. Figures 11 and 12The active areas 9, 9' shown each belong to a separate PV module 2. However, the interconnection of active areas 9, 9' explained below can also be applied analogously to PV modules 2 that have several electrically separated active areas 9, 9', especially if these are not arranged next to each other but one above the other in the PV system.

[0113] At the in Figure 11 In the circuit shown, an upper active surface 9 is connected in parallel to a lower active surface 9' located directly below it, so that the current flow through, for example, the upper left active surface 9 can be different from the current flow through the lower left active surface 9'. This allows the lower active surface 9', which is located at a different height than the upper active surface 9 above it, to be operated at a different electrical operating point than the upper active surface 9.

[0114] This parallel circuit is connected in series to another identical parallel circuit, formed by the two right-hand active surfaces 9 and 9'. Due to the double parallel connection, the currents in each of the depicted active surfaces 9 and 9' can vary.

[0115] At the in Figure 12 In the circuit shown, the two upper active surfaces 9 are connected to each other in series. These two active surfaces 9 thus form an upper electrical line 21 according to the invention. In the same way, the two lower active surfaces 9' are connected to each other in series to form a lower electrical line 21. The upper and lower electrical lines 21 are connected in parallel and can therefore, for example, be fed to a common inverter input.

[0116] Alternatively, each of the two electrical lines 21 of the circuit could also be used. Figure 12be assigned to a separate inverter input. In this case, the two electrical lines 21 would thus be electrically separated from each other.

[0117] While in Figure 12 Since the same current flows through the two upper active surfaces 9, the current flow through the upper electrical line 21 can differ from the current flow through the lower electrical line 21. In other words, the lower active surfaces 9' can be operated at an operating point that differs from that at which the two upper active surfaces 9 operate, as is also the case with the in Figure 11 The wiring shown is the case.

[0118] The Figures 13 and 14Finally, Figure 1 shows a cross-sectional view through an upper and a lower beam 5, each represented by the hatched areas, of a support structure 3 according to the invention. The bifacial PV modules 2 are suspended from the support structure 3 in such a way that they can pivot about an axis of rotation 25, as indicated by the double arrows, as soon as a significant wind load acts on the PV modules 2. The axis of rotation 25 preferably runs approximately parallel to the beams 5. According to the invention, it can be advantageous if the pivoting movement of the PV modules 2 is dampened by an additional device.

[0119] At the in Figure 13 In the illustrated embodiment, a retaining element 15 is provided below the upper rectangular bar 5, which encompasses the PV module 2 on both sides and is itself rotatably attached to the upper bar 5 about the axis of rotation 25.

[0120] At the in Figure 14In the illustrated embodiment, the bars 5 are designed with a round outer contour, so that the retaining element 15, which holds the PV module 2, can surround the bar 5 in a ring shape and thus pivot together with the PV module 2 about the axis of rotation 25, formed by the central axis of the upper bar 5.

[0121] In summary, for the economical and energy-efficient use of a PV system 1 with upright, in particular bifacial, PV modules 2, and especially for largely avoiding shading of the PV modules 2, a very simple to manufacture and assemble support structure 3 is proposed, which is constructed by vertical posts 4 connected to each other at intersection points and horizontally running beams 5, so that right-angled mounting fields 6 can be provided for the individual PV modules 2, wherein the posts 4 and beams 5 can preferably each be formed in a material-saving manner by common profiles 12, 22 and wherein in particular a division of the posts 4 into two connectable sections 7, 8 significantly facilitates the assembly overall;Secondly, the invention proposes an electrical interconnection such that superimposed active surfaces 9, 9' can be operated at different electrical operating points, and thus preferably separately operated electrical lines 21 are formed, which are preferably arranged horizontally. This allows the effects of shading of PV modules 2 on the efficiency of the energy conversion of the PV system 1 to be further minimized. Reference symbol list

[0122] 1 Photovoltaic system 2 PV module 3 Supporting structure 4 Post 5 Beam 6 Mounting panel 7 Fastening section 8 Holding section 9 (Upper) active area 9 (Lower) active area 10 Holding surfaces 11 Flange 12 Profile of 4 13 Tab 14 Opening, in particular through-hole, of 4 (for 5) 15 Holding elements 16 Groove section 17 Cross-sectional reduction 18 System area 19 Management clearance 20 Row 21 Electrical row 22 Profile of 5 23 Opening, in particular through-hole, of 5 (for 15) 24 Chamfer 25 Axis of rotation 26 Clearance

Claims

1. Photovoltaic (PV) system (1) with several bifacial PV modules (2) arranged upright on a support structure (3), wherein the support structure (3) has several posts (4) which are attached to or in the ground, in particular anchored, wherein bars (5) are attached to the posts (4) which connect two adjacent posts (4) together and wherein each pair of posts (4) and two bars (5) define a substantially rectangular mounting field (6) in which at least one PV module (2) is arranged, characterized by - that the PV modules (2) are attached to the bars (5), - that For this purpose, retaining elements (15) are provided and - that The retaining elements (15) provide groove sections (16) into which an edge of the respective PV module (2) is inserted.

2. Photovoltaic system (1) according to claim 1, characterized by the fact thatthe posts (4) are essentially vertical and / or the bars (5) are essentially horizontally oriented and / or several, in particular up to four, PV modules (2) are arranged one above the other in a vertical direction.

3. Photovoltaic system (1) according to claim 1 or 2, characterized by the fact that the posts (4) are divided at least into a fastening section (7) connected to the ground and a holding section (8) which can be connected or is connected to it and extends above the fastening section (7) and / or that horizontally adjacent PV modules (2) are arranged offset from each other in a vertical direction.

4. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact thatThe active surfaces (9) of the PV modules (2) are arranged at a distance from the posts (4) and / or beams (5), in particular such that at least up to an angle of incidence of 20°, particularly preferably at least up to an angle of incidence of 30°, shading of the active surface (9) by posts (4) is excluded and / or that at least up to an angle of incidence of 25°, preferably at least up to an angle of incidence of 30° or even 40°, shading of the active surface (9) by beams (5) is excluded.

5. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact that the active surfaces (9) of the PV modules (2) are arranged asymmetrically spaced apart from posts (4) and / or beams (5) on opposite sides and / or the PV modules (2) are suspended pivotably on the supporting structure (3) about an axis of rotation (25) which preferably runs approximately parallel to the beams (5).

6. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact that Retaining surfaces (10) are formed on the posts (4) to which an associated bar (5) can be attached over a surface, in particular wherein the retaining surfaces (10) are formed as flanges (11) on a profile (12) and / or as tabs (13) on an opening (14) in a profile (12).

7. Photovoltaic system (1) according to claim 6, characterized by the fact that the retaining surfaces (10) are formed in pairs in order to grip a bar (5) inserted between the retaining surfaces (10) on both sides, and / or that the bars (5) are narrower than the posts (4), in particular narrower than a distance between retaining surfaces (10) formed in pairs.

8. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact thatthrough-holes (14) are formed on the posts (4) to accommodate a bar (5) or its end, in particular wherein at least one or the holding section (8) of the posts (4) is formed in the form of an omega profile.

9. Photovoltaic system (1) according to claim 8, characterized by the fact that two bolts (5) are placed in a through-hole (14) or that only one bolt (5) is placed in a through-hole (14), while another bolt (5) is mounted on a side of the post (4) opposite the through-hole (14) without a through-hole (14) and by means of retaining surfaces (10) formed on the post (4), in particular wherein a bolt (5) inserted through a through-hole (14) and another bolt (5) are attached to a retaining surface (10).

10. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact thatthe posts (4) have at least in the holding section (8) a profile (12) with a C-shaped, U-shaped, Z-shaped or S-shaped basic shape, in particular wherein additional holding surfaces (10) are formed as flanges (11) at the ends of the profile (12).

11. Photovoltaic system (1) according to one of the preceding claims, wherein a retaining element (15) has two opposing groove sections (16) and / or wherein the bars (5) have a chamfer (24) on a bottom side.

12. Photovoltaic system (1) according to claim 11, characterized by the fact that The retaining elements (15) each have a cross-sectional reduction (17) so that a retaining element (15) can be inserted or inserted into a through-hole (14) formed on a bar to a defined insertion depth, in particular wherein a contact surface (18) is formed on the retaining element (15) with which the retaining element (15) lies flat against the bar (5).

13. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact that A free space (26) is kept between the ground and a lowest barrier (5), in particular wherein the free space (26) has a height of at least 50 cm, at least 60 cm or at least 1 m, in particular wherein rows (20) of the PV system (1) are spaced apart such that a management free space with a width of at least 6 meters, at least 8 meters or at least 10 meters exists between the rows (20).

14. Photovoltaic system (1) according to one of the preceding claims, characterized by the fact that the PV modules (2) and the supporting structure (3) essentially form one plane and / or the PV modules (2) are arranged in several spaced-apart rows (20), wherein the PV modules (2) of a row (20) essentially form one plane.

15. Photovoltaic system (1) according to claim 14, characterized by the fact thata distance between two rows (20) is at least three times, preferably at least four times, particularly preferably at least five times the maximum height of an active area (9) of the PV system (1).