• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention refers to a method and a photovoltaic panel inspection system based on luminescence measurements, comprising: covering means, switchable between two states of different opacity, to be arranged on the photovoltaic panel and covering at least one first cell from a group of cells from said panel; a shell covering part of a second cell of the group of cells; image capture means, housed in the housing, to obtain images of luminescence emitted by the second cell; and a microprocessor to obtain the luminescence, from the images obtained for the phases of different opacity of the covering means and determines the state of the photovoltaic panels based on the luminescence variation. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2802473A1
    申请号:ES201930640
    申请日:2019-07-10
    公开日:2021-01-19
    发明作者:Barba Rufino Barco；Rebollo Miguel Angel Gonzalez；Lopez Juan Jimenez；Sacristan Oscar Martinez；Fernandez Angel Moreton；Conde Sofia Rodriguez；Gomez Victor Alonso；Shabnam Dadgostar
    申请人:Universidad de Valladolid；
    IPC主号:
    专利说明:

    [0003] OBJECT OF THE INVENTION
    [0004] The present invention relates to the technical field of renewable energies and more specifically to the inspection and quality control of photovoltaic modules in operation by, for example, electroluminescence measurements.
    [0006] BACKGROUND OF THE INVENTION
    [0007] Currently, in the inspection of photovoltaic modules by luminescence it is necessary to disconnect the panel from the electrical network to be able to apply an electrical voltage through a power supply.
    [0009] The disconnection of the panel is a safety problem and a loss of production, since, although the characterization of a single panel does not require much time, in photovoltaic plants the panels are connected in large series.
    [0011] Therefore, the state of the art lacks a solution that allows controlling the proper functioning of the solar installations in a safe way and that does not interfere with the normal operation of the panels.
    [0013] DESCRIPTION OF THE INVENTION
    [0014] In order to achieve the objectives and avoid the drawbacks mentioned above, the present invention describes, in a first aspect, a system for inspecting a photovoltaic panel comprising:
    [0015] - Cover means, switchable between two states of different opacity, configured to be arranged on the photovoltaic panel and cover at least one first cell of a group of cells of said panel;
    [0016] - a housing dimensioned to cover a part of a second cell of the group of cells;
    [0017] - image capture means, housed in the housing, configured to obtain images of luminescence emitted by the covered part of the second cell; Y
    [0018] - a microprocessor that has an image processing software configured to obtain the luminescence variation of the second cell, based on the luminescence images obtained for the different opacity states of the covering means and determine an operating state based on the luminescence variation obtained.
    [0020] The system of the present invention contemplates in one of its embodiments a solid state relay, housed in the housing, which controls the switching of the covering means from a first opaque state to a second opaque state and vice versa. Thus, the opacity conditions of the covering means can advantageously be controlled, in order to subsequently determine the luminescence image by subtracting the images obtained with different opacity of the covering means. In one of the preferred embodiments, the covering means comprise at least one electrochromic crystal.
    [0022] The image capture means in one of the embodiments of the present invention comprise a camera with a sensor to be selected from: a Si sensor, an InGaAs sensor, or an InSb sensor, or any other type of sensor sensitive to luminescence emitted by the photovoltaic module.
    [0024] Additionally, the present invention contemplates other electronic elements housed inside the housing, such as, for example, according to one of the embodiments of the invention, a battery for storing energy and a power supply connected to the means for capturing energy. picture. Thus, the inspection system of the present invention is advantageously provided with greater autonomy and avoids its dependence on other auxiliary devices.
    [0026] In one of the preferred embodiments of the present invention, means of displacement of the system are contemplated over the entire surface of the photovoltaic panel to be inspected, where the means of displacement are arranged in a frame on which the covering means and the Case. In one of the realizations These particular means of movement consist of a set of soft material wheels arranged in the lower part of the frame. Thus, advantageously, the inspection equipment can traverse the panel without causing any damage or scratches, since the moving means is the only physical contact that the photovoltaic panel receives during an inspection operation.
    [0028] Optionally, an upper cover is contemplated in the casing, where said cover is attached to the rest of the casing by means of pivoting means of the hinge type that allow its opening. Thus, the electronic components housed inside the housing can advantageously be protected, but without giving up having access to them for replacement or repair, for example.
    [0030] Optionally, a side cover is contemplated on the housing, where said side cover is attached to the rest of the housing by means of pivoting hinge-type means that allow its lateral opening to access the chamber.
    [0032] In one of the embodiments of the invention, the inspection equipment is structured so that the cover means and the housing are arranged in planes perpendicular to each other. Thus, equipment can be made, for example, with an "L" or an inverted "T" shape that are appropriate to combine a good shading effect on the cells (by arranging the covering means in a plane parallel to that of the panel), and good imaging (by arranging the housing in a plane perpendicular to the panel) so that the imaging means housed within it focuses perpendicularly on the cells being inspected.
    [0034] According to a particular embodiment of the invention, the inverted "T" -shaped configuration of the invention comprises a first electrochromic crystal arranged transversely to one side of the housing and a second electrochromic crystal arranged in the same plane as the first crystal. , but on the opposite side of the case.
    [0036] Alternatively, in one of the embodiments of the invention, the housing has a rectangular section sized to cover, when placed on a photovoltaic panel to be inspected, half of at least two cells. Thus, advantageously, the team of inspection can reduce the time and length of travel required to inspect the entire panel by imaging multiple cells at the same time.
    [0038] A second aspect of the invention refers to a method for inspecting a photovoltaic panel that comprises the steps of:
    [0039] - covering, by means of covering means with a first degree of opacity, at least one first cell of a group of cells of the photovoltaic panel;
    [0040] - covering, by a housing, a part of a second cell of the group of cells of the photovoltaic panel, where the uncovered part is exposed to solar radiation; - obtaining, by means of image capture housed in the housing, a first luminescence image produced in the first part of the cell as a result of the solar radiation received in the uncovered part;
    [0041] - modify the opacity of the covering means to a second opacity degree;
    [0042] - obtaining a second luminescence image of the first part of the cell;
    [0043] - obtaining the variation of the luminescence of the second cell as a result of subtracting the first and the second luminescence images; Y
    [0044] - determining an operating state based on the variation in luminescence obtained.
    [0046] In one of the embodiments of the invention, when there is a lot of ambient light, to better eliminate noise it is contemplated to repeat the luminescence imaging cycle several times.
    [0048] In one of the embodiments of the invention, an image processing software specifically developed to obtain the luminescence variation of the second cell is stored in the microprocessor, based on the luminescence images obtained for the different opacity states of the covering media. and determining an operating state based on the obtained luminescence variation.
    [0050] According to an embodiment of the invention, to modify the opacity of the covering means, an electric field is applied to the covering means, switched by means of a solid state relay, also synchronizing, by the microprocessor, the opacity modifications of the blanking media with luminescence imaging.
    [0051] In one of the embodiments of the present invention, the measurement of the luminescence variation in the images is performed by subtracting, pixel by pixel, the two images obtained with different opacity of the covering means, subsequently generating a new image with the result of said subtraction.
    [0053] Additionally, the present invention contemplates: determining a travel route that, with suitable displacement means, allows an inspection device comprising the image capture means and the covering means to travel the surface of the photovoltaic panel following the programmed route. Thus, the need for manual guidance of the device is advantageously eliminated and allows optimal planning of the movements necessary for the inspection of the panel to be carried out. In one of the embodiments of the invention, specifically developed software makes it possible to program certain travel routes and subsequently load them into the microprocessor.
    [0055] The measurement through electroluminescence of the present invention makes it possible to detect possible manufacturing errors or damage caused during transportation or assembly of the panels very quickly and without involving any additional operation to disconnect elements that pose risks to personnel and a productive loss.
    [0057] In addition, throughout the useful life of photovoltaic panels, the method and system of the present invention allows a much more frequent monitoring of their operation compared to the inspections carried out by traditional methods that require physical manipulation of them, connecting equipment additional and / or disconnecting the photovoltaic panels, which makes said inspections are much more spaced in time and, therefore, the chances of detecting an early failure are reduced.
    [0059] Additionally, the measurements are made during the panel operation so the results are more faithful to the state of the panel working.
    [0061] BRIEF DESCRIPTION OF THE FIGURES
    [0062] To complete the description of the invention and in order to help a better understanding of its characteristics, according to a preferred example of the embodiment of the same, a set of drawings is attached where, by way of illustration and not limitation, the following figures have been represented:
    [0064] - Figure 1 represents one of the particular embodiments of the invention where a dimensioned housing is provided to cover two half cells and two shading covering elements.
    [0066] - Figure 2 represents one of the particular embodiments of the invention, where the cover of the housing in the open position allows one to observe the electronic components housed inside.
    [0068] - Figure 3 represents a plan view of an embodiment of the present invention arranged on a photovoltaic panel, with a complete example path.
    [0070] DETAILED DESCRIPTION OF THE INVENTION
    [0071] The present invention discloses a method and a system to inspect photovoltaic panels by means of a luminescence analysis, with the panel in operation and without altering the connections of the installation, where the excitation source used is directly sunlight. Thus, the basic operation consists of covering one of the cells 4 of a photovoltaic panel 3 , to limit the current in the cells connected in series, increasing the probability of radiative recombination and increasing the luminescence signal emitted by the cells connected in series.
    [0073] To achieve the above effect, the present invention advantageously takes advantage of the common configuration of photovoltaic panels in series of cells with protection diodes, in which to prevent a malfunction of the entire panel in the event of the appearance of shaded areas or the appearance of hot spots When detecting a malfunction in any one of the cells, current stops flowing through the series of cells, diverting it through the protection diode, allowing the rest of the series of cells of the photovoltaic panel to continue in normal operation.
    [0075] Figure 1 shows one of the preferred embodiments of the invention where a housing 1 is arranged, which houses the electronic components of the system, sized to simultaneously cover two half cells of a photovoltaic panel 3 , and where the The system also comprises a pair of covering elements, in this case electrochromic glasses 2, one at the front and the other at the rear, for shading the cells of the photovoltaic panel 3 . This embodiment represented in figure 1 is configured to cover, in part, two cells for the same reason that it has two electrochromic crystals, and it is none other than to optimize the movements necessary to carry out luminescence measurements of all cells. of the photovoltaic panel, but the operation is the same with a housing dimensioned to cover part of a single cell and using a single covering element.
    [0077] To capture the base luminescence of the inspection method and the system of the present invention, according to one of the preferred embodiments, the system has a camera, which preferably has an InGaAs sensor, which detects the emission of luminescence caused in the part of the cell that is being covered (or what is the same, the part of the cell that is not being directly exposed to the sun) of the panel in operation, caused by the excitation that causes direct exposure to sunlight from the other part of the cell.
    [0079] In figure 2 , an upper cover 21 of the housing 1 is shown which, in the open position, allows the main electronic components of the system to be observed. In one embodiment, the system has a power supply 22 to power the camera 23 , a battery 24 , a microprocessor 25, and a solid state relay 26 . To access the camera lens, a side cover 27 is arranged at the bottom of the housing.
    [0081] The design of the casing 1 has a section of rectangular geometry dimensioned to cover at least half a cell, so that the chamber 23 is arranged on the inside focusing perpendicularly towards the part of the cell that is covered by the casing itself. This part that the camera focuses on is not being excited by sunlight, but currents caused by the photoelectric effect produced by sunlight in the part of the cell that is not covered by the housing are what cause the luminescence captured by the camera.
    [0083] Luminescence is observed when the electron-hole pairs are radiatively recombined in sufficient quantity. Said radiative recombination can be increased by exposing the photovoltaic panel to the sun and at the same time limiting the current in a group of cells connected in series. In this way, the separation of the pairs outside the solar cell is limited, increasing the radiative recombination and therefore increasing the luminescence emission in the entire cell, which makes it possible to observe the luminescence in the inspected area.
    [0085] The limitation of the current in a group of cells of the photovoltaic panel occurs as a consequence of the shading of a cell, so that as it receives less radiation from the sun, it produces less current than in the rest of the unshaded cells. The shaded cell then behaves like a diode in reverse, preventing the passage of a greater current than it produces. To avoid this effect, photovoltaic panels generally have protection diodes or bypass diodes that protect the photovoltaic panel from the effects of hot spots and shaded spots, which negatively affect the performance of the panel by forcing a shaded cell to dissipate powers so high that they lead to deterioration of said cell. This situation is what solves the protection diodes, which are installed in parallel with a group of cells connected in series and thus offer an alternative path to current in the event of a fault. For example, according to the most common configuration of today's panels, in which they are divided into three groups of cells in series, a defect in one cell affects only one third of the panel and leaves the other two thirds operating normally.
    [0087] The method and system of the present invention take advantage of this configuration of the photovoltaic panels with protection diodes to limit the current in a group of cells of the photovoltaic panel 3 shading some of them by means of a covering element and, simultaneously, covering with the housing 1 half the surface area of a cell under analysis from the same group of cells, so that the covered half is focused by camera 23 to collect an image of the luminescence that is produced. For example, in the case of a panel divided into three groups of cells, by shading a cell (also referred to herein as a control cell), the current is limited to one third of the cells in the panel. By limiting the current, the separation of the hollow electron pairs is made more difficult, favoring the increase in radiative recombination by increasing the luminescence emission.
    [0088] For shading the control cell, a covering element is used which, in one of the preferred embodiments, is an electrochromic crystal. Electrochromic crystals basically work by varying the orientation of their fibers depending on the application of an electric field, which allows modifying its opacity. In the present invention, the electric field that varies the opacity of the electrochromic crystal 2 is controlled with the solid state relay 26 .
    [0090] The coverage of cells by means of electrochromic crystals provides a high level of reliability to the present invention, since it allows contrasting the images taken by the camera under two different conditions of controlled opacity and obtained consecutively with a very short time interval, which minimizes the effects of the great variability of sunlight that filters through the housing and mixes with the emission of luminescence.
    [0092] The method of the present invention obtains each of the images in two different states, a first state with the polarized electrochromic crystal, in which there is less opacity and a second state with the unpolarized electrochromic crystal, in which the opacity is higher. In the state in which the electrochromic glass is more opaque, the current is more limited, whereby more radiative recombination occurs in the inspected area, which leads to a higher emission of luminescence than in the polarized state of the electrochromic glass.
    [0094] Once the two luminescence images corresponding to the two states of different opacity have been obtained, said images are subtracted to obtain the luminescence emitted by the cell.
    [0096] The result of subtracting the images is the elimination of noise due to sunlight itself, obtaining the resulting luminescence. The microprocessor 25 is configured to receive the two images captured by the camera 23 , and obtain a new image that is the result of subtracting the two images pixel by pixel.
    [0098] For higher quality and more reliable results, it is advisable to run multiple cycles of images to prevent variability in atmospheric conditions from influencing the luminescence inspection result. In these cycles the capture of the camera and the opacity of the electrochromic glass are synchronized. The opacity of the glass is controlled by the relay 25 , while the microprocessor 25 controls its synchronization with the captures of the camera 23 . Next, the images are processed to obtain the final image, which is actually composed of relative values derived from the processing described above of the gray levels of the images taken.
    [0100] An alternative embodiment of the present invention, instead of electrochromic crystals as cover elements, comprises a screen with TFT thin film transistor technology, which provides greater opacity than electrochromic crystals.
    [0102] In Figure 3 the system of the present invention is observed from a plan perspective, where the system has been arranged on a photovoltaic panel 3 to be inspected. In the initial position, it is sufficient that one of the electrochromic crystals covering elements covers a cell, but the embodiment shown with two crystals minimizes the necessary displacements, also allowing the inspection of the rows of cells located at the top and bottom of the table. module support. The photovoltaic panel is in normal operating conditions while the system performs the inspection, without the need to disconnect the panels and require specialized personnel to perform additional actions. The system of the present invention moves through the panel following the zigzag path indicated by arrows 31 (although any other path could be followed, but for efficiency reasons it will be more convenient to define the shortest path possible).
    [0104] The movement of the inspection system of the present invention on the photovoltaic panel is carried out with a minimum physical contact between them, where preferably all contact is limited to wheels (not represented in the figures) made of soft material that avoid scratching the panel. A frame 28 is arranged on said wheels that supports the cover elements 2 in a plane perpendicular to that of the housing and which, at the same time, during the inspection operation, are arranged in a plane parallel to that of the photovoltaic panel 3 .
    [0106] In the present invention, therefore, there is a compact and autonomous inspection equipment that incorporates all the necessary elements to take luminescence images of the cells of a photovoltaic panel that runs completely for their complete characterization. Once the inspection of the photovoltaic panel is completed, the information collected by the inspection team is a set of images of Relative luminescence (obtained from the subtraction of the luminescence images under two different opacity conditions of the covering element) that represent measures of the luminescence variation of each of the cells, variation generated thanks to the fact that it has been forced on its group of cells an area shaded by a covering element.
    [0108] From the luminescence variation information for each of the cells, the photovoltaic panel is fully characterized and it is easy to know its status and identify any malfunction in it. On the one hand, the relative intensity of the signal is directly associated with the state of the panel, to the extent that the more “luminous” the image is, the more luminescence the cell is emitting and the better the state of the panel. In addition, it is possible to observe areas in which there are variations of the emitted signal that correspond to different types of defects such as breaks, electrically isolated areas and others, which can appear in the solar panels.
    [0110] The present invention should not be limited to the embodiment described herein. Other configurations can be made by those skilled in the art in light of the present description. Accordingly, the scope of the invention is defined by the following claims.
    权利要求:
    Claims (15)
    [1]
    1. System to inspect a photovoltaic panel (3) characterized in that it comprises:
    - Cover means (2), switchable between two states of different opacity, configured to be arranged on the photovoltaic panel and cover at least one first cell of a group of cells of said panel;
    - a housing (1) dimensioned to cover a part of a second cell of the group of cells;
    - image capture means (23), housed in the housing, configured to obtain images of luminescence emitted by the covered part of the second cell; Y
    - a microprocessor (25) configured to obtain a luminescence variation of the second cell, based on the luminescence images obtained for the different opacity states of the covering means and determine an operating state based on the luminescence variation obtained.
    [2]
    System according to claim 1, further comprising a solid state relay (26) housed in the housing, which controls the switching of the covering means from a first opaque state to a second opaque state and vice versa.
    [3]
    3. System according to any of the preceding claims, wherein the covering means comprise an electrochromic crystal.
    [4]
    4. System according to any of the preceding claims, wherein the covering means comprise a first electrochromic crystal arranged transversely to one side of the housing and a second electrochromic crystal arranged in the same plane as the first crystal, but on the opposite side of the housing, such that a side view of the system is shaped like an inverted T.
    [5]
    System according to any of the preceding claims, wherein the covering means comprise a tft-type screen.
    [6]
    System according to any of the preceding claims, wherein the image capture means comprise a sensor to be selected from: an InGaAs sensor, a Si sensor and an InSb sensor or any other sensor sensitive to the luminescence emitted by solar cells.
    [7]
    7 . System according to any of the preceding claims, further comprising a battery (24) and a power supply (22) housed inside the housing.
    [8]
    8 . System according to any of the preceding claims, which also comprises moving means to move the system over the entire surface of the photovoltaic panel, where the moving means are arranged in a frame (28) on which the cover means are also arranged. and the casing.
    [9]
    9 . System according to any of the preceding claims, wherein the casing further comprises an upper cover, which is attached to the rest of the casing by means of pivoting hinge-type means that allow it to be opened.
    [10]
    10 . System according to any of the preceding claims, wherein the housing further comprises a side cover, which is attached to the rest of the housing by means of pivoting hinge-type means that allow its lateral opening to access the chamber.
    [11]
    11 . System according to any of the preceding claims where the covering means and the casing are arranged in planes perpendicular to each other.
    [12]
    12. Method to inspect a photovoltaic panel characterized by comprising:
    - covering, by means of covering means (2) with a first degree of opacity, at least one first cell of a group of cells of the photovoltaic panel;
    - covering, by a casing (1), a part of a second cell of the group of cells of the photovoltaic panel, where the uncovered part is exposed to solar radiation; - obtaining, by means of image capture (23) housed in the housing, a first luminescence image produced in the first part of the cell as a result of solar radiation received in the uncovered part;
    - modify the opacity of the covering means (2) to a second opacity degree; - obtaining a second luminescence image of the first part of the cell; - obtaining a variation in the luminescence of the second cell as a result of subtracting, by a microprocessor (25), the first and second luminescence images; Y
    - determining an operating state based on the variation in luminescence obtained.
    [13]
    13 . Method according to claim 12, where modifying the opacity of the covering means comprises applying an electric field to the covering means by means of a solid state relay and where it also comprises synchronizing, by the microprocessor, the opacity modifications of the means coverts with luminescence imaging.
    [14]
    14 . Method according to any of claims 12-13, where obtaining the luminescence variation comprises:
    - subtract the two images pixel by pixel; Y
    - generate a new image with the result of the pixel by pixel subtraction of the two images.
    [15]
    15 . Method according to any of claims 12-14, further comprising:
    - storing a travel path in the microprocessor; Y
    - moving, by means of movement, an inspection device comprising the image capture means and the covering means over the surface of the photovoltaic panel following the stored path.
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    同族专利:
    公开号 | 公开日
    ES2802473B2|2021-11-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2016118975A1|2015-01-23|2016-07-28|Alliance For Sustainable Energy, Llc|Luminescence imaging systems and methods for evaluating photovoltaic devices|
    WO2018098516A1|2016-12-01|2018-06-07|Bt Imaging Pty Ltd|Determining the condition of photovoltaic modules|
    US20180262159A1|2017-03-09|2018-09-13|Alliance For Sustainable Energy, Llc|Illuminated outdoor luminescence imaging of photovoltaic modules|
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