Vertical installation for generating electricity by means of photovoltaics

Abstract

The invention relates to an installation (1) for generating electricity by means of photovoltaics, wherein the installation (1) has at least four solar modules (2), wherein the solar modules (2) are distributed between at least two solar surfaces (3) so that each solar surface (3) has at least two solar modules (2), wherein the solar surfaces (3) are vertically one above another in a parallel offset arrangement, wherein the solar modules (2) are connected in at least two strings (4, 5), wherein each of the at least two strings (4, 5) comprises at least one solar module (2) on at least two different solar surfaces (3), wherein each string (4, 5) is assigned a usable depth (6, 7), wherein the usable depth (6, 7) corresponds to the maximum distance between the solar modules (2) of the string (4, 5) and an outer edge (8) of the solar surface (3) of the relevant solar module (2), wherein the strings (4, 5) have at least two different usable depths (6, 7).

Description

[0001] Vertical system for generating electricity using photovoltaics

[0002] The invention relates to a system for generating electricity by means of photovoltaics, wherein the system has at least four solar modules, wherein the solar modules are distributed over at least two solar surfaces, so that each solar surface has at least two solar modules, wherein the solar surfaces are arranged vertically offset one above the other in parallel.

[0003] When generating electricity using photovoltaics to power more than just small devices such as wristwatches or radios, it is necessary to use a large number of solar modules to achieve the required level of performance. The solar modules can be arranged in a single, for example horizontal, solar array. Depending on the location of the system and the available space, it is advantageous to divide the solar modules into several, typically parallel, solar arrays. This enables, for example, optimal orientation of the solar arrays based on the average angle of solar radiation. The solar arrays are arranged vertically one above the other to reduce the system's footprint. Regardless of the direction in which the parallel arrays are arranged, a balance must be struck between optimal use of the incoming sunlight and temporary mutual shading of the solar arrays.Completely avoiding shadowing at any time of day also means that at many times of the day, especially at the sun's highest position and thus at its maximum light intensity, a portion of the incoming sunlight remains unused. Conversely, making the most complete use of incoming light at the sun's highest position and at the optimal angle of incidence simultaneously means that parts of the system are shaded at other times of the day.

[0004] In practice, it is not economical to connect each solar module individually or in parallel to an inverter. The cabling and installation work required would be disproportionately high. Therefore, several solar modules are usually connected in series and connected together to an inverter. The disadvantages of shading solar modules in such a series connection are well known. In particular, each solar module is usually combined with a freewheeling diode (i.e. connected in parallel) to protect it from the power of the other solar modules in the series in the event of shading or a fault. Although the shaded solar module still receives radiant energy and could therefore deliver PV power (albeit to a lesser extent), this power is lost.

[0005] In addition, US 4,966,631 A proposes to coordinate the arrangement of the solar modules connected in series with an expected shadow pattern, for example parallel to the earth's surface.

[0006] JP 2002-061126 A shows a noise barrier with vertical photovoltaics, with additional inclined PV elements arranged underneath. The modules are arranged in strings that run parallel and offset in the direction of travel and can extend across both solar panels. The shadow of a passing car should always affect only part of the strings.

[0007] US 2014 / 028104 Ai shows parallel solar arrays. However, the sub-strings are limited to the individual solar arrays and each is wired to its own inverter.

[0008] Also in DE 10 2019 008062 Ai, EP 3 007234 Ai and US 2018 / 323639 Ai only strings within a solar area are shown.

[0009] JP 2021-145496 A shows a ground-mounted photovoltaic system (also called a solar park). The solar panels are naturally arranged in a horizontally offset manner—in the open space. This is therefore a different type of system than the one disclosed in the present disclosure.

[0010] It is an object of the invention to avoid or reduce efficiency drops of the system due to different shading of the solar modules over the course of the day and at the same time to reduce the effort of the cabling between the individual solar panels and the inverter.

[0011] The solution according to the invention provides that the solar modules are connected in at least two strings, wherein each of the at least two strings comprises at least one solar module on at least two different solar surfaces, wherein each string is assigned a usable depth, wherein the usable depth corresponds to the maximum distance of the solar modules of the string from an outer edge of the solar surface of the respective solar module, wherein the strings have at least two different usable depths.

[0012] In everyday language, the terms “solar panel” and “solar module” are not clearly defined and are sometimes used synonymously in German, while in English, other meanings of “solar panel” and “solar module” are common. For the sake of clarity, the terms “solar panel” and “solar module” are therefore defined separately in this disclosure and not synonymously. A solar module comprises one or more solar cells. In this disclosure, a solar module is understood to be an assembly of one or more solar cells that provides the total power of the combined solar cells via a common two-pole electrical connection. A solar module is the smallest unit that is electrically connected. For purposes other than transmitting electrical power, additional poles of the electrical connections can of course be provided. The solar cells within the solar module can be connected in series and / or parallel.Within a solar area, the solar modules can be embedded in larger structures. For example, the solar modules can be mechanically embedded in solar panels. A solar panel is a mechanical structural unit. Several solar modules can be arranged within a solar panel, e.g., geometrically parallel. A solar panel can have several "outputs," which are electrical connections designed to transmit electrical power. In this case, each output corresponds to a solar module. A solar panel with multiple outputs therefore has several solar modules and is therefore not a "solar module" in itself. Several solar panels can themselves be arranged in rows or arrays. The strings can correspond to the panels, rows, or arrays, or they can subdivide them. For example, it is generally conceivable that the solar modules of a panel, row, or array belong to the same string or different strings.Each solar module can only belong to one string.

[0013] Due to the different usable depths, the solar modules are shaded at different times and to different extents throughout the day. The usable depth refers to the solar module or modules within the string with the greatest distance from an outer edge of the respective solar surface. This means that the distance is determined between the solar module and the outer edge of the solar surface in which the solar module is arranged. The extent of shading of the solar surfaces can naturally be the same or similar for parallel solar surfaces, in particular if the solar surfaces are arranged in a structure with three or more surfaces at equal distances. The effect of the invention is generally also achieved for solar surfaces that deviate from exact parallelism. As long as there is an essentially simultaneous development of shading over the course of the day, i.e.If a consistent degree of shading is achieved at different times during the day, the solar surfaces are to be understood as parallel within the meaning of the claims and are covered by the present disclosure.

[0014] Assuming all solar modules are identical, the reference point of the solar module is irrelevant for determining the distance (and thus the usable depth), as the distance is only relevant as a relative measurement. If solar modules with different geometries are used, the decisive distance for determining the usable depth would be the distance measured between the point on the solar module furthest from the outer edge of the solar panels ("deepest") and the outer edge.

[0015] The different usable depths mean that the string with the shallower usable depth can deliver a proportionally greater output than if only a single string per solar panel or multiple strings with the same (i.e., equally large) usable depth were used. This reduces the system's efficiency loss due to shading throughout the day.

[0016] Due to the arrangement of the solar panels vertically one above the other, offset in parallel, the shading effect is greater the closer the direction of the solar radiation is to a vertical line over the course of the day. At the same time, when the sun is relatively high in the sky over the course of the day, the achievable output is also greatest (assuming the solar panels are optimally oriented). At a relatively low sun position over the course of the day, when no significant shading of the solar panels is to be expected due to the vertical arrangement (i.e. the shadow of one solar panel falls on a neighboring solar panel and shades it partially or completely), the achievable output is also substantially lower than when the sun is relatively high.In other words, the effect of self-shading in the vertical arrangement disclosed here begins at a fundamentally higher power level due to the position of the sun than would be the case with a horizontal arrangement, where self-shading increases with the lower position of the sun. Expressed in concrete terms, the shadow contrast is stronger at the sun's highest point than at a lower position of the sun. This results in a more significant power difference depending on the usable depth of the solar modules than would be the case with a horizontal arrangement. Avoiding or reducing the disadvantage of this power difference with the circuit disclosed here is therefore more important with the vertical arrangement than with a horizontal arrangement.

[0017] Optionally, each string can be a series connection of individual solar modules. Typically, a freewheeling diode (or bypass diode) is connected in parallel with each solar module. The freewheeling diode prevents the entire string from having to be shut down in the event of a defect in the associated solar module.

[0018] In this configuration, for example, all solar modules in a string can be the same distance from the outer edge of the respective solar module's solar surface. Accordingly, all solar modules within a string experience the same degree of shading from a parallel, offset solar surface. Therefore, all solar modules within this string can operate at the same reduced power level, specifically, they can deliver the same reduced current, so that each individual solar module operates optimally relative to its own shading. Depending on the extent of shading, the power level between the different strings can vary significantly.

[0019] According to an alternative optional configuration, each string can be a series connection of parallel-connected groups of solar modules. Typically, a blocking diode is connected in series with each solar module. The blocking diode prevents the output voltage of the entire group from collapsing in the event of a failure of the associated solar module.

[0020] In this alternative configuration, for example, all groups in a string can have the same usable depth, with the usable depth of a group corresponding to the maximum distance of the solar modules in the group from an outer edge of the solar surface of the respective solar module. Within the parallel-connected group, a reduction in the current supplied by individual group members (i.e. individual solar modules within the group) can be accepted because this does not limit the current supplied by the other group members. However, the total current of the individual groups connected in series should be the same in order to make the best possible use of the power of the unshaded group members. The distribution of the distances of the individual group members to the outer edge of the respective solar surface can therefore be the same for all groups.As it turns out, this configuration can increase the efficiency of the system by up to 40%, depending on the arrangement of the solar panels.

[0021] According to an optional embodiment, at least two solar modules of a solar array can be mechanically connected in a panel, wherein the panel has at least two electrical connections, each electrical connection being connected to at least one solar module, so that the solar modules of the panel can be connected via different, separate connections. The interconnection of several solar modules facilitates production, handling, and installation.

[0022] In this context, it can be provided, in particular, that each solar module of the panel has exactly one row of solar cells, with the rows of the at least two solar modules arranged in parallel. This achieves the minimum width of a row for a given geometry of the solar cells. Thus, all solar cells in a row operate at the same operating point when shadowed by an adjacent, parallel surface or solar surface (i.e., parallel to the outer edge) and thus deliver the same power. Each cell delivers the same current possible for it, and no power is lost due to the series connection of the cells.

[0023] The outer edges of the solar panels of the system can optionally lie in an imaginary connecting plane, whereby the imaginary connecting plane forms an angle of 90° with a horizontal line. At their outer edges, the solar panels form an angle of greater than 0° with the imaginary connecting plane. The solar panels are therefore not located in a common plane. The imaginary connecting plane is a vertical plane, with the smallest possible footprint of the system. A vertical imaginary connecting plane exists when the present disclosure is used on a noise barrier to generate electricity using photovoltaics. The solar panels can be formed, for example, by the upper sides of slats of the noise barrier. The noise barrier can, for example, be constructed from wall elements as in WO 2020 / 056441 Ai, with the properties disclosed there.The efficiency losses due to shading are greater in these configurations and with a conventional connection of the solar modules than with a horizontal imaginary connection plane, so that the benefit of the invention in reducing these losses is particularly evident here.

[0024] The at least two strings can be connected to different inverters or to independent inputs of an inverter. The strings generally supply different currents. For the most efficient use of the supplied current, separate inverter directions can therefore be provided. Optionally, the inverter outputs can be connected in parallel to combine the output power of the individual strings downstream of the inverter(s). Specifically, the string connections can each be connected to independent maximum power point (MPP) trackers, which can be integrated, for example, in the inverter(s).

[0025] The invention will be further explained below using particularly preferred embodiments, to which it is not intended to be limited, and with reference to the drawings. The drawings show in detail:

[0026] Fig. 1 schematically shows the structure of a system according to a first embodiment of this disclosure with four solar surfaces arranged offset in parallel;

[0027] Fig. 2 schematically shows the structure of a system according to a second embodiment of this disclosure, wherein two solar modules connected in series form a panel; and Fig. 3 schematically shows the structure of a system according to a third embodiment of this disclosure, wherein two parallel-connected groups each with two solar modules connected in series form a panel.

[0028] Fig. 1 shows a system 1 for generating electricity using photovoltaics. In a basic configuration (solid lines), the system has four solar modules 2. The four solar modules 2 are distributed across two solar panels 3. Each solar panel 3 has two solar modules 2. The solar panels 3 are arranged offset in parallel. In this basic configuration, the solar modules 2 are connected in two strings 4, 5. Each of the two strings 4, 5 comprises a solar module 2 on each of the two solar panels 3. Each string 4, 5 is a series connection of individual solar modules 2. Each string 4, 5 is assigned a usable depth 6, 7.

[0029] The usable depth 6, 7 corresponds to the maximum distance of the solar modules 2 of the respective string 4, 5 from an outer edge 8 of the solar surface 3 of the respective solar module 2. The outer edges 8 of the solar surfaces 3 lie in an imaginary connecting plane 9. In this exemplary embodiment, the imaginary connecting plane 9 is a vertical plane. The solar surfaces 3 are mounted, for example, on the upper sides of corresponding slats of a noise barrier. The two strings 4, 5 have different (therefore two) usable depths 6, 7. In this exemplary embodiment, all solar modules 2 of a string 4, 5 have the same distance from an outer edge 8 of the solar surface 3 of the respective solar module 2. Accordingly, the solar modules 2 of a string 4, 5 in this case all supply the same current strength per string.

[0030] In the lamellar arrangement of solar modules 2 shown here with several parallel rows 10, 11 of solar modules 2, individual module rows 10 of a lamella with a shorter distance to the open sky receive more radiant energy than those module rows 11 with a greater distance. If lamellas are arranged in such a way that at certain times of day in direct sunlight individual rows 10, 11 of modules are self-shading within the lamellas, the difference in radiant energy between rows of modules 10, 11 at different distances from the open sky becomes even more pronounced. Within a lamella, if the adjacent parallel rows 10, 11 with different distances from the open sky were connected in series, all module rows would only deliver the power of the module row 11 with the lowest received radiant energy.When freewheeling diodes are arranged per module row, one or more module rows with lower power or partial shade are completely switched off. This loss is particularly pronounced in slatted arrangements of multi-row solar modules with narrow spacing between the slats, or stacked vertically or diagonally.

[0031] In the first embodiment shown in Fig. i, the two strings 4, 5 are connected to different inverters or to independent inputs of an inverter via electrical terminals 12, 13. More precisely, each string 4, 5 is connected to its own MPP tracker. This allows the optimal power level for each string 4, 5 to be determined and utilized.

[0032] Apart from the basic configuration, several extended configurations are illustrated in Fig. 1. The dashed lines show a first extended configuration with an additional four solar modules 14 per solar panel 3, as well as two further solar panels 15, each with six solar modules 16. In total, in this first extended configuration, twelve solar modules 2, 14, 16 are connected in series per string 4, 5. Within each string 4, 5, additional freewheeling diodes 17, 18 can be provided, for example to bridge an upper or lower half of the string 4, 5. This means that if one part of the string 4, 5 fails, the other half can continue to be used. This can be useful, for example, in the event of contamination or mechanical damage in the lower area of ​​a noise barrier, in order to switch off entire solar panels across all strings.

[0033] A second expanded configuration is illustrated in dotted lines in Fig. 1. Six additional solar modules 19 are schematically indicated per solar panel 3, 15, so that the number of solar modules is doubled compared to the first expanded configuration. The additional solar modules 19 are arranged at a greater usable depth and are accordingly connected in series in two additional strings 20, 21. The feasibility and efficiency of such additional module rows 22 depends on the distance 23 between the solar panels 3, 15 and the angle 24 between the solar panels 3, 15 and the imaginary connecting plane 9, relative to the angle of incidence of the sun's light 25. The greater the distance 23, the greater the benefit of extended usable depths and corresponding strings.

[0034] For all configurations, an uppermost solar surface 26 is schematically indicated in Fig. 1. This is naturally not affected by shading effects. Therefore, for the uppermost solar surface 26, all solar modules, regardless of their distance from the outer edge 8, can be connected in a common series circuit and connected together to a separate connection of the inverter in a conventional manner. In the second exemplary embodiment shown in Fig. 2, 4 or 5 panels 27, each with two solar modules 28 connected in series, are connected in series per string. The panels 27 are connected in arrays 29 that extend perpendicular to the outer edge 8. The individual panels 27 of an array 29 thus have different usable depths 6, 7 and therefore belong to different strings 4, 5 according to this exemplary embodiment. Otherwise, the second exemplary embodiment corresponds to the first exemplary embodiment and uses the same reference numerals.

[0035] The third exemplary embodiment shown in Fig. 3 differs from the first exemplary embodiment in particular in that each string 4, 5 is a series connection of parallel-connected groups 30 of solar modules 31. All groups 30 of a string 4, 5 have the same usable depth 32, 33. The usable depth 32, 33 of a group 30 corresponds to the maximum distance of the solar modules 31 of the group 30 from an outer edge 8 of the solar surface 3 of the respective solar module 31. This maximum distance is determined by the "deepest" solar module 31 of the group 30. To avoid repetition, with regard to the other features in Fig. 3, reference is made to the explanations for the first exemplary embodiment and Fig. 1.

Claims

Claims:

1. A system (1) for generating electricity by means of photovoltaics, the system (1) comprising at least four solar modules (2), the solar modules (2) being distributed over at least two solar surfaces (3), such that each solar surface (3) has at least two solar modules (2), the solar surfaces (3) being arranged vertically one above the other in parallel offset fashion, characterized in that the solar modules (2) are connected in at least two strings (4, 5), each of the at least two strings (4, 5) comprising at least one solar module (2) on at least two different solar surfaces (3), each string (4, 5) being assigned a usable depth (6, 7), the usable depth (6, 7) corresponding to the maximum distance of the solar modules (2) of the string (4, 5) from an outer edge (8) of the solar surface (3) of the respective solar module (2), the strings (4, 5) having at least two different usable depths (6, 7).

2. System (1) according to claim 1, characterized in that each string (4, 5) is a series connection of individual solar modules (2).

3. System (1) according to claim 2, characterized in that all solar modules (2) of a string (4, 5) have the same distance from an outer edge (8) of the solar surface (3) of the respective solar module (2).

4. System (1) according to claim 1, characterized in that each string (4, 5) is a series connection of parallel-connected groups (30) of solar modules (31).

5. Plant (1) according to claim 4, characterized in that all groups (30) of a strand (4, 5) have the same usable depth (32, 33), wherein the usable depth (3 2 > 33) of a group (30) corresponds to the maximum distance of the solar modules (31) of the group (30) from an outer edge (8) of the solar surface (3) of the respective solar module (31).

6. System (1) according to one of claims 1 to 5, characterized in that at least two solar modules of a solar surface are arranged mechanically connected in a panel, wherein the panel has at least two electrical connections, wherein each electrical connection is connected to at least one solar module, so that the solar modules of the panel can be connected via different, separate connections. 7- System (1) according to claim 6, characterized in that each solar module of the Panels have exactly one row of solar cells, wherein the rows of at least two solar modules are arranged in parallel.

8. System (i) according to one of claims 1 to 7, characterized in that the outer edges (8) of the solar surfaces (3) lie in an imaginary connecting plane (9), wherein the imaginary connecting plane (9) encloses an angle of 90° with a horizontal.

9. System (1) according to one of claims 1 to 8, characterized in that the at least two strings (4, 5) are connected to different inverters or to independent inputs of an inverter.

10. Noise barrier, wherein a system according to one of claims 1 to 9 is installed on the noise barrier.

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