Photovoltaic cell panel invisible defect detection device based on high dynamic range imaging

Abstract

The invention discloses a photovoltaic cell panel invisible defect detection device based on high dynamic range imaging, and relates to the technical field of solar cell panel application, the device comprises a light emitting assembly, an area-array camera assembly and a control assembly; the light-emitting component is used for acting on the photovoltaic cell panel to enable the photovoltaic cell panel to generate photoluminescence or electroluminescence; the area-array camera assembly is used for receiving an exposure instruction issued by the control assembly so as to change the exposure quantity; photoluminescence images or electroluminescent images of the photovoltaic cell panel under different exposure quantities are shot; the control assembly is also used for performing fusion processing on the photoluminescence images of the photovoltaic cell panel under different exposures to obtain a photoinduced defect image of the photovoltaic cell panel; and carrying out fusion processing on the electroluminescent images of the photovoltaic cell panel under different exposures to obtain an electrogenerated defect image of the photovoltaic cell panel. According to the invention, high-efficiency and high-definition imaging detection of invisible defects of the photovoltaic panel can be realized in any environment.

Description

Technical Field

[0001] The present application relates to the technical field of solar panel applications, and in particular to a photovoltaic panel invisible defect detection device based on high dynamic range imaging. Background Art

[0002] Crystalline silicon photovoltaic panels are important components of current solar power generation facilities. These components may have internal or surface defects during product manufacturing or power generation operation, and many defects are invisible to the human eye. For example, surface contamination, hidden cracks, debris, black spots, broken grids, local heating, etc. These defects are important factors affecting the photoelectric conversion efficiency and service life of photovoltaic panels, and even bring hidden safety hazards. Therefore, countries around the world are actively developing detection technology for invisible defects of photovoltaic panel components. Imaging detection technology has become the mainstream of invisible defect detection technology for photovoltaic panel components due to its comprehensive, intuitive, high sensitivity and high efficiency.

[0003] Electroluminescence imaging and photoluminescence imaging are currently the key technologies to be developed because they can detect a wide variety of defects with high efficiency. In recent years, electroluminescence imaging and photoluminescence imaging have been applied to online inspection under sunlight; however, under high sunlight irradiance, electroluminescence imaging and photoluminescence imaging will be disturbed by the reflected image of ambient light, making it difficult to obtain high-definition defect images. Summary of the invention

[0004] The purpose of this application is to provide a photovoltaic panel invisible defect detection device based on high dynamic range imaging, which can realize high-efficiency and high-definition imaging detection of photovoltaic panel invisible defects in any environment.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] The present application provides a photovoltaic panel invisible defect detection device based on high dynamic range imaging, comprising a light emitting component, an area array camera component and a control component; the control component is connected to the area array camera component;

[0007] The light-emitting component is used to: act on the photovoltaic cell panel to make the photovoltaic cell panel generate photoluminescence or electroluminescence;

[0008] The area array camera component is used to: receive the exposure instruction sent by the control component to change the exposure amount; and take the photoluminescence image or electroluminescence image of the photovoltaic panel under different exposure amounts;

[0009] The control component is also used to: fuse the photoluminescence images of the photovoltaic panel under different exposure amounts to obtain a photo-induced defect image of the photovoltaic panel; and fuse the electroluminescence images of the photovoltaic panel under different exposure amounts to obtain an electro-induced defect image of the photovoltaic panel.

[0010] According to the specific embodiments provided by the present application, the present application has the following technical effects: the present application provides a photovoltaic panel invisible defect detection device based on high dynamic range imaging, whether facing electroluminescence or photoluminescence, the luminous images of the photovoltaic panel under different exposures are captured by the area array camera component; thus, under the background of photoluminescence or electroluminescence, various invisible defects on the surface and inside of the photovoltaic panel are revealed. Then, the control component performs fusion processing, so as to fuse the high-exposure image with the low-exposure image, and the transition exposure position pixels with the low-exposure position pixels, so as to obtain a corresponding high-definition defect image without over-exposure areas and too dark areas. Based on the fusion processing of the luminous images of the photovoltaic panel under different exposures mentioned above, effective detection can be achieved in both high-irradiance environments and low-irradiance environments, overcoming the interference of ambient light on imaging.

[0011] In summary, the defect image finally obtained by the present application takes into account the defect information in the too dark or too bright areas, and improves the actual imaging dynamic range; the imaging of the present application can be applied to both photoluminescence imaging and electroluminescence imaging, and can realize efficient detection of invisible defects of photovoltaic panels in high irradiance environments or low irradiance environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 This is a schematic diagram of the composition principle of a photovoltaic panel invisible defect detection device based on high dynamic range imaging in one embodiment of the present application.

[0014] Figure 2 It is a structural schematic diagram of a photovoltaic panel invisible defect detection device based on high dynamic range imaging in a daylight environment when the light-emitting component is an electroluminescent driving power component in one embodiment of the present application.

[0015] Figure 3 It is a structural schematic diagram of a photovoltaic panel invisible defect detection device based on high dynamic range imaging in a daylight environment when the light-emitting component is a photoexcitation light source component in one embodiment of the present application.

[0016] Figure 4 Schematic diagram of filter transmittance, InGaAs camera spectral sensitivity, and photo / electrospectral curves in one embodiment of the present application.

[0017] Figure numerals: 1-electroluminescent driving power supply assembly, 2-photovoltaic panel, 3-photoexcitation light source assembly, 4-filter, 5-array camera, 6-control assembly, 7-sunlight, 8-photovoltaic panel photoinduced defect image, 9-photovoltaic panel electroinduced defect image, 10-near-infrared light source, 11-beam expander. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] In the imaging detection of invisible defects of solar panels under high irradiance, the radiance of the photoluminescent or electroluminescent target has the characteristics of high dynamic range, and it is difficult to capture clear defect images based on the quantization accuracy of ordinary photoelectric sensors, so it is necessary to use high dynamic range imaging methods. Based on this, the present application provides a photovoltaic panel invisible defect detection device based on high dynamic range imaging, which overcomes the interference of high irradiance of ambient light on photoluminescent imaging and electroluminescent imaging, thereby achieving high-efficiency and high-definition detection of invisible defects of photovoltaic panels.

[0020] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0021] In an exemplary embodiment, Figure 1 As shown, a photovoltaic panel invisible defect detection device based on high dynamic range imaging is provided, comprising a light emitting component, an array camera component and a control component 6; the control component 6 is connected to the array camera component. The photovoltaic panel 2 detected by the device is a polycrystalline silicon photovoltaic panel or a monocrystalline silicon photovoltaic panel, and the spectral range of the photoluminescence or electroluminescence generated by the photovoltaic panel 2 is: 1050nm-1250nm.

[0022] In a specific application, the light-emitting component is used to act on the photovoltaic panel 2 so that the photovoltaic panel 2 generates photoluminescence or electroluminescence. Under the background of electroluminescence or photoluminescence, various invisible defects on the surface and inside of the photovoltaic panel 2 are revealed, and during this manifestation process, the photovoltaic panel 2 will also generate reflected light. Corresponding to the spectral range of the photovoltaic panel 2 mentioned above, the crystalline silicon photovoltaic panel generates electroluminescence under the action of the electroluminescent driving voltage, and the spectral energy of the electroluminescence is mainly concentrated in the short-wave infrared range of 1050nm to 1250nm; the crystalline silicon photovoltaic panel generates photoluminescence under the irradiation of the photoluminescent light source, and the spectral energy of the photoluminescence is mainly distributed in the short-wave infrared range of 1050nm to 1250nm.

[0023] In a specific application, the area array camera assembly is used to: receive an exposure instruction sent by the control assembly 6 to change the exposure amount; and capture photoluminescence images or electroluminescence images of the photovoltaic panel 2 under different exposure amounts.

[0024] Specifically, the area array camera assembly includes a filter 4 and an area array camera 5 which are arranged in sequence; the filter 4 is a narrowband filter or a bandpass filter, and the central wavelength of the filter 4 is near 1150nm, so most of the interference of ambient light on the photoluminescent image or the electroluminescent image can be filtered out. In other words, the central wavelength of the filter 4 is 1150nm±Δ, where Δ is the wavelength floating range.

[0025] The spectral transmittance curve of the filter 4 matches the spectral sensitivity curve of the area array camera 5. The area array camera 5 is a near-infrared camera or a short-wave infrared camera, including a short-wave infrared InGaAs camera, a near-infrared silicon CCD camera, a near-infrared silicon CMOS camera and other types of short-wave infrared cameras, and the above cameras have high sensitivity in the wavelength range of 1050nm-1250nm.

[0026] In a specific application, the control component 6 is also used to: fuse the photoluminescence images of the photovoltaic panel 2 under different exposure amounts to obtain a photovoltaic panel photo-induced defect image 8; fuse the electroluminescence images of the photovoltaic panel 2 under different exposure amounts to obtain a photovoltaic panel electro-induced defect image 9.

[0027] Specifically, the control component includes an exposure control unit and an image acquisition unit. The exposure control unit is respectively connected to the near-infrared light source 10, the area array camera component and the image acquisition unit. The exposure control unit is used to: issue an exposure instruction to the area array camera component to change the exposure amount; while issuing the exposure instruction, issue an acquisition instruction to the image acquisition unit to acquire the luminous image corresponding to the exposure instruction. The exposure instruction refers to the exposure time, which is controllable, and different exposure times can be selected according to the radiation brightness or radiation intensity of the target being photographed. In particular, when the light-emitting component is a photoexcitation light source component 3, the exposure time is associated with the emission power of the near-infrared light source. In addition, the image acquisition unit is used to: capture the photoluminescence image or electroluminescence image of the photovoltaic panel 2 under different exposure amounts, so as to obtain a high dynamic range photoluminescence image sequence or electroluminescence image sequence of the photovoltaic panel.

[0028] In a specific practical application, the control component 6 is a microcomputer, and the microcomputer is provided with an input and output interface. The microcomputer is connected to the area array camera component through the input and output interface. The microcomputer sends exposure instructions to the area array camera component through the input and output interface to control the exposure of the camera and achieve shooting with different exposure amounts.

[0029] In another specific application, when the light-emitting component is an electroluminescent driving power supply component 1, the light-emitting component is a set of reverse DC voltage sources applied to the PN junction of the photovoltaic panel; the magnitude of the reverse DC voltage output by the reverse DC voltage source is associated with the series resistance or parallel resistance of the photovoltaic panel. When working, the reverse DC voltage source outputs a reverse DC voltage to act on the photovoltaic panel 2, so that the photovoltaic panel 2 generates electroluminescence.

[0030] like Figure 2As shown, the device of the present application works under sunlight 7, that is, under high irradiance, and the settings of the various components in the device are as follows: electroluminescent driving power supply component 1, filter 4 is a 1150nm narrow-band filter, area array camera 5 is an area array InGaAs camera, and control component 6 is a microcomputer. When working, the photovoltaic panel 2 generates electroluminescence and forms a defect image under the action of the electroluminescent driving power supply component 1. In this process, it will also be affected by the reflected light of the photovoltaic panel 2 itself. The electroluminescence and reflected light formed on the surface of the photovoltaic panel 2 pass through the 1150nm narrow-band filter and are photographed by the area array InGaAs camera. The area array InGaAs camera exchanges data through the peripheral interface of the microcomputer, changes the exposure time under the control of the microcomputer, and shoots electroluminescent images with different exposure amounts, such as low-exposure electroluminescent images and high-exposure electroluminescent images. The microcomputer fuses the electroluminescent images with different exposure amounts, and finally obtains a clear electroluminescent defect image 9 of the photovoltaic panel with a high dynamic range.

[0031] In a specific application, when the light-emitting component is a photoexcitation light source component 3, the light-emitting component includes a near-infrared light source 10 and a beam expander 11; when working, the near-infrared light source 10 emits a laser, which is shaped by the beam expander 11 and evenly projected onto the photovoltaic panel 2 to induce the photovoltaic panel 2 to produce photofluorescence.

[0032] The near-infrared light source 10 is a near-infrared narrowband light source, such as a laser light source with a wavelength of 808nm or 850nm; or, the near-infrared light source 10 is an LED light source with a wavelength of 850nm. The near-infrared light source 10 can also be a semiconductor laser with a central wavelength of 850nm. The beam expander 11 is mainly composed of an optical lens, and the beam expander 11 expands the point-shaped light spot emitted by the infrared light source 10 into light spots of various shapes, including circular light spots and rectangular light spots, as needed. The beam expander 11 can also adjust the size and shape of the light spot as needed.

[0033] like Figure 3As shown, the device of the present application works under sunlight 7, that is, under high irradiance, and the arrangement of the components in the device is as follows: the photoexcitation light source assembly 3 includes a near-infrared light source 10 and a beam expander 11, the near-infrared light source 10 uses an 808nm laser, the filter 4 is a 1150nm narrow-band filter, the array camera 5 is an array InGaAs camera, and the control assembly 6 is a microcomputer. When working, the 808nm laser, under the control of the exposure control system, emits a light beam according to a certain laser emission power, which is evenly projected on the surface of the photovoltaic panel 2 after being shaped by the beam expander 11, and induces the photovoltaic panel 2 to generate photofluorescence and form a defect image. In this process, it will also be affected by the reflected light of the photovoltaic panel 2 itself. The photofluorescence and reflected light formed on the surface of the photovoltaic panel 2 pass through the 1150nm narrow-band filter and are photographed by the array InGaAs camera. The area array InGaAs camera exchanges data through the peripheral interface of the microcomputer, changes the exposure time under the control of the microcomputer, and takes photoluminescence images with different exposure amounts, such as low-exposure photoluminescence images and high-exposure photoluminescence images. The microcomputer fuses the photoluminescence images with different exposure amounts, and finally obtains a clear photo-induced defect image of the photovoltaic panel with a high dynamic range 8.

[0034] In another specific application, when the light-emitting component includes an electroluminescent driving power component 1 and a photoexcitation light source component 2, relevant personnel can switch between the two as needed. In the same detection process, only the electroluminescent driving power component 1 or the photoexcitation light source component 2 can be used. When one of them works, the other does not work. Regardless of whether the electroluminescent driving power component 1 or the photoexcitation light source component 2 is used for light emission, Figure 4 As shown, it is a schematic diagram of the filter transmittance, InGaAs camera spectral sensitivity, and photo / electrospectral curves during the luminescence process.

[0035] In another specific application, the photoluminescence images of the photovoltaic panel under different exposures are fused to obtain a photovoltaic panel light-induced defect image, including: based on a preset pixel retention rule, the photoluminescence images of the photovoltaic panel under different exposures are fused by replacing pixels at the same position to obtain a photovoltaic panel light-induced defect image. Similarly, a photovoltaic panel electrical defect image can be obtained.

[0036] The fusion processing of images with different exposure amounts mentioned in this application takes the fusion of two images as an example, one is a low-exposure image and the other is a high-exposure image. The characteristic of the low-exposure image is that there is no overexposed area in the whole image, but the dynamic range is low, and there are often too dark image areas, so the image details in the too dark area are difficult to distinguish, and the image in the too dark area needs to be discarded through fusion. The characteristic of the high-exposure image is that there is an overexposed area, and the image details of the area cannot be recognized, but at the same time, the brightness and image details of other images without overexposed areas are improved. Therefore, the same-position pixel replacement method can be used to replace the pixel values ​​of the overexposed position in the high-exposure image with the pixel values ​​in the low-exposure image at the same position, based on which a clear defective image with no overexposed area and no too dark area can be obtained.

[0037] In the prior art, due to the limitation of the performance of photoelectric sensors, the quantization accuracy of the camera is limited, for example, 8 bits or 12 bits. Therefore, when the brightness of different areas of the target image varies greatly, it is difficult for an image taken by an ordinary camera to take into account both the dark and bright areas at the same time. In contrast, the present application fuses images with different exposure amounts, removes the overexposed image areas, and finally obtains a defective image of a photovoltaic panel with a high dynamic range. The dynamic range of imaging refers to the range of quantization accuracy of imaging. The present application is applicable to photoluminescence imaging mode and electroluminescence imaging mode. By fusing images with different exposure amounts, the imaging clarity of the target is improved, which also increases the actual imaging dynamic range of the camera.

[0038] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A photovoltaic panel invisible defect detection device based on high dynamic range imaging, characterized in that: The photovoltaic panel invisible defect detection device based on high dynamic range imaging includes a light emitting component, an area array camera component and a control component; the control component is connected to the area array camera component; The light-emitting component is used to: act on the photovoltaic cell panel to make the photovoltaic cell panel generate photoluminescence or electroluminescence; The area array camera component is used to: receive the exposure instruction sent by the control component to change the exposure amount; and take the photoluminescence image or electroluminescence image of the photovoltaic panel under different exposure amounts; The control component is also used to: fuse the photoluminescence images of the photovoltaic panel under different exposure amounts to obtain a photo-induced defect image of the photovoltaic panel; and fuse the electroluminescence images of the photovoltaic panel under different exposure amounts to obtain an electro-induced defect image of the photovoltaic panel.

2. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 1 is characterized in that: When the light-emitting component is a photoexcitation light source component, the light-emitting component includes a near-infrared light source and a beam expander; when working, the near-infrared light source emits a laser, which is shaped by the beam expander and evenly projected onto the photovoltaic cell panel to induce the photovoltaic cell panel to generate photoluminescence; When the light-emitting component is an electroluminescent driving power component, the light-emitting component is a set of reverse DC voltage sources applied to the PN junction of the photovoltaic panel; when working, the reverse DC voltage source outputs a reverse DC voltage to act on the photovoltaic panel, so that the photovoltaic panel generates electroluminescence.

3. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 1 is characterized in that: The area array camera assembly comprises a filter and an area array camera which are arranged in sequence; the filter is a narrowband filter or a bandpass filter; the area array camera is a near-infrared camera or a short-wave infrared camera; The spectral transmittance curve of the filter matches the spectral sensitivity curve of the area array camera.

4. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 1, characterized in that: The photovoltaic cell panel is a polycrystalline silicon photovoltaic cell panel or a monocrystalline silicon photovoltaic cell panel, and the spectral range of the photoluminescence or electroluminescence generated by the photovoltaic cell panel is: 1050nm-1250nm.

5. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 2, characterized in that: The control component includes an exposure control unit and an image acquisition unit; The exposure control unit is connected to the near-infrared light source, the area array camera assembly and the image acquisition unit respectively; the exposure control unit is used to: issue an exposure instruction to the area array camera assembly to change the exposure amount; while issuing the exposure instruction, issue an acquisition instruction to the image acquisition unit to acquire the luminous image corresponding to the exposure instruction; the exposure instruction refers to the exposure time, and when the light-emitting assembly is a photoexcitation light source assembly, the exposure time is associated with the laser emission power of the near-infrared light source; The image acquisition unit is used to capture photoluminescence images or electroluminescence images of the photovoltaic cell panel under different exposure amounts.

6. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 2, characterized in that: The beam expander is mainly composed of an optical lens; The magnitude of the reverse DC voltage output by the reverse DC voltage source is associated with the series resistance or parallel resistance of the photovoltaic panel.

7. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 2, characterized in that: The near-infrared light source is: a laser light source with a wavelength of 808nm or 850nm; or, the near-infrared light source is: an LED light source with a wavelength of 850nm.

8. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 3 is characterized in that: The central wavelength of the filter is 1150nm±Δ, where Δ is the wavelength floating range.

9. The photovoltaic panel invisible defect detection device based on high dynamic range imaging according to claim 1, characterized in that: In the control component, the photoluminescence images of the photovoltaic cell panel under different exposure amounts are fused to obtain a photo-induced defect image of the photovoltaic cell panel, including: Based on a preset pixel retention rule, the photoluminescence images of the photovoltaic panel under different exposure amounts are fused by replacing pixels at the same position to obtain a photovoltaic panel light-induced defect image.

Images