JP2017060246A - Inspection method and inspection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method and an inspection system that make it difficult to suffer an influence of an external environment, thereby enabling high-precision inspection of a photovoltaic power generation panel or a photovoltaic power generation cell.SOLUTION: An inspection method for inspecting an inspection target panel (power generator) 4 comprises a connection step of electrically connecting a reference panel 16 as a photovoltaic power generation panel having a known power generation efficiency to the inspection target panel 4 in series, an energization step of supplying electric current to the inspection target panel 4 and the reference panel 16, an imaging step of imaging the inspection target panel 4 and the reference panel 16 that emit light in the energization step together by using a camera 21, a comparison step of comparing the luminance of an image portion of the inspection target panel 4 and the luminance of an image portion of the reference panel 16 within one image P obtained in the imaging step, and a calculation step of calculating the power generation efficiency of the inspection target panel 4 based on the comparison result obtained in the comparison step and the power generation efficiency of the reference panel 16.SELECTED DRAWING: Figure 1

Description

  The present invention particularly relates to an inspection method and an inspection system for inspecting a power generation unit of photovoltaic power generation.

  As such a technique, for example, an inspection method described in Patent Document 1 is known. In this inspection method, a bias current is passed in the forward direction of the solar cell module to be inspected, light having a wavelength of 800 nm to 900 nm generated from the solar cell module is detected, and an emission distribution image representing the EL emission state of the solar cell module is obtained. doing. In the method described in Patent Document 1, measurement and evaluation are performed by replacing the current distribution of the amorphous layer of the solar cell module with EL light emission. Thereby, the presence or absence of film formation distribution abnormality of a solar cell module and the defective part of an integration state are specified.

  Further, in this inspection method, a predetermined light emission distribution image as a reference for comparison is compared with a light emission distribution image of the solar cell module, and a low-luminance area is higher than a predetermined ratio in the light emission distribution image of the solar cell module. When it is included, the solar cell module is selected as outside of normal.

JP 2012-089790 A

  In the inspection method described above, a predetermined light emission distribution image as a reference for comparison is prepared as a standard separately from the light emission distribution image for actually inspecting the solar cell module. Various conditions for photographing differ between the light emission distribution image serving as a reference and the light emission distribution image of the solar cell module to be inspected. For example, camera settings differ slightly from shooting to shooting. The weather varies with each photo. As described above, the conventional method is affected by the external environment, and it is difficult to accurately inspect.

  An object of this invention is to provide the inspection method and inspection system which can test | inspect a photovoltaic power generation panel or a photovoltaic power generation cell accurately by making it difficult to receive the influence of an external environment.

  One aspect of the present invention is an inspection method for inspecting a power generation unit that is a solar power generation panel or a solar power generation cell, and a reference panel that is a solar power generation panel having a known power generation efficiency with respect to the power generation unit. Electrical connection in series, an energization process for supplying current to the power generation unit and the reference panel, an imaging process for photographing the power generation unit and the reference panel that emit light in the energization process together using a camera, and imaging In one image obtained in the process, the comparison step of comparing the luminance of the image portion of the power generation unit and the luminance of the image portion of the reference panel, the comparison result obtained in the comparison step, and the power generation efficiency of the reference panel And a calculation step of calculating the power generation efficiency of the power generation unit.

  According to this inspection method, the power generation unit and the reference panel are connected in series, and current is supplied to them. By this energization, the power generation unit and the reference panel emit light. The light-emitting power generation unit and the reference panel are photographed together by a camera. One image obtained by this photographing includes an image portion of the power generation unit that emits light and an image portion of the reference panel that emits light. Since there is a correlation between the light emission intensity of the photovoltaic power generation panel and the power generation efficiency, the ratio of the power generation efficiency of the power generation unit to the power generation efficiency of the reference panel can be obtained by comparing the luminance of these image portions. Since the power generation efficiency of the reference panel is known, the power generation efficiency of the power generation unit can be quantitatively calculated based on the power generation efficiency. In this inspection method, since the power generation unit and the reference panel are photographed together, the imaging conditions of the reference panel and the imaging conditions of the power generation unit are the same. Therefore, when comparing the image portions, the influence of the external environment is offset and the influence is not easily received. Therefore, even when the external environment changes, a highly accurate inspection is realized. As a result, it is possible to easily determine the quality (for example, the degree of deterioration) of the solar power generation panel or the solar power generation cell in use at the power plant or the like.

  In some embodiments, in the energization process, a pulse current is supplied to the power generation unit and the reference panel. In this case, the background light can be easily canceled by taking the difference between the light emission amount when the current is on and the light emission amount when the current is off. By canceling the background light, the signal-to-noise ratio (Signal-Noise ratio) can be improved.

  In some embodiments, in the energization process, a pulse current whose current value is changed stepwise is supplied to the power generation unit and the reference panel. In this case, current-luminescence characteristics can be acquired. Thereby, the degradation condition of the power generation unit can be clearly determined.

  In some embodiments, in the energization process, a pulse current is supplied at a current value that is greater than or equal to the ratings of the power generation unit and the reference panel. In this case, it is easy to eliminate the influence of background light (for example, sunlight or lighting).

  In some embodiments, in the imaging process, imaging is performed with a gate time wider than the time width of the pulse current in the energization process. In this case, the influence of background light can be minimized by setting the gate time of the camera to the minimum time including the time width of the pulse current.

  One embodiment of the present invention is an inspection system for inspecting a power generation unit that is a solar power generation panel or a solar power generation cell, and is a solar system that is electrically connected to the power generation unit in series and has a known power generation efficiency. A reference panel that is a photovoltaic power generation panel, a power supply device for supplying current to the power generation unit and the reference panel, a power generation unit that is supplied with current by the power supply device, and a camera for photographing the reference panel together, The brightness of the image portion of the power generation unit and the brightness of the image portion of the reference panel in one image taken by the camera are compared, and based on the comparison result and the power generation efficiency of the reference panel, the power generation of the power generation unit A calculation unit that calculates efficiency.

  According to this solar power generation panel inspection system, the power generation unit and the reference panel are connected in series, and current is supplied to them by the power supply device. By this energization, the power generation unit and the reference panel emit light. The light-emitting power generation unit and the reference panel are photographed together by a camera. One image obtained by this photographing includes an image portion of the power generation unit that emits light and an image portion of the reference panel that emits light. Since there is a correlation between the light emission intensity of the photovoltaic power generation panel and the power generation efficiency, the ratio of the power generation efficiency of the power generation unit to the power generation efficiency of the reference panel can be obtained by comparing the luminance of these image portions. Since the power generation efficiency of the reference panel is known, the power generation efficiency of the power generation unit can be quantitatively calculated by the calculation unit based on the power generation efficiency. In this inspection system, since the power generation unit and the reference panel are imaged together, the imaging conditions of the reference panel and the imaging conditions of the power generation unit are the same. Therefore, when the calculation unit compares the image portions, the influence of the external environment is offset and the influence is less likely to be received. Therefore, even when the external environment changes, a highly accurate inspection is realized. As a result, it is possible to easily determine the quality (for example, the degree of deterioration) of the solar power generation panel or the solar power generation cell in use at the power plant or the like.

  According to some aspects of the present invention, it is difficult to be affected by the external environment, and even when the external environment changes, a highly accurate inspection is realized.

It is a figure showing a schematic structure of an inspection system of one embodiment of the present invention. It is a flowchart which shows the test | inspection procedure of an electric power generation part. It is a flowchart which shows the test | inspection imaging | photography procedure in FIG. (A) is a figure which shows the time change of the pulse current supplied, (b) is a figure which shows the time change of the light-emission quantity in a photovoltaic power generation panel. It is the schematic which shows the image part of the electric power generation part contained in a picked-up image, and the image part of a reference | standard panel. It is a figure which shows the relationship of the pure light emission amount with respect to the electric current value in an electric power generation part. (A) is a figure which shows the pulse current supplied with the electric current value more than a rating, (b) is a figure which shows the light emission amount in the case of setting gate time with respect to pulse current and its pulse width.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  An inspection system 1 according to an embodiment will be described with reference to FIG. The inspection system 1 is a system for determining the quality (deterioration degree, etc.) of the power generation unit by estimating the power generation efficiency of the power generation unit which is a solar power generation panel or a solar power generation cell. The inspection system 1 is applied to a string 2 of photovoltaic power generation. The string 2 is a group of units in which a plurality of photovoltaic panels are directly connected so as to obtain a predetermined output voltage. The string 2 includes a plurality of blocks 3, and the block 3 includes a plurality of photovoltaic power generation panels. Hereinafter, the photovoltaic power generation panel to be inspected by the inspection system 1 is referred to as an inspection target panel 4. In this case, the inspection object panel 4 corresponds to a power generation unit that is an object of inspection by the inspection system 1. In addition, the test | inspection system 1 and the test | inspection method demonstrated below can also test | inspect for each photovoltaic power generation cell 6 which comprises a photovoltaic power generation panel.

  In the example shown in FIG. 1, one string 2 is composed of 12 panels 4 to be inspected in 3 rows, with 4 rows in one row. Each inspection object panel 4 includes a plurality of photovoltaic power generation cells 6. The photovoltaic power generation cell 6 is, for example, a silicon-based cell, but may be another type of cell. In each inspection object panel 4, a plurality of photovoltaic power generation cells 6 are arranged vertically and horizontally. In this inspection system 1, for example, each block 3 is a target of one inspection.

  In the inspection system 1, an EL (Electro Luminescence) emission phenomenon by supplying a current to the inspection target panel 4 is used. The inspection system 1 includes a power supply unit 10 for supplying a current to a block 3 including a plurality of inspection target panels 4 and an imaging unit 20 for imaging the block 3 that emits EL and acquiring a light emission image. Prepare.

  The power supply unit 10 is configured to be able to supply power to individual strings 2 (in string units). The power supply unit 10 includes a connection unit 8 to which a wire for supplying current is connected, a power management device 11 that controls the current supplied to the string 2, and a power source that supplies power via the power management device 11. Device 12. The connection unit 8, the power management device 11, and the power supply device 12 are electrically connected to each other. The power supply unit 10 further includes a power-supply side GPS (Global Positioning System) 13 for the power management device 11 to synchronize with the camera 21 of the photographing unit 20, and a current and a voltage supplied from the power management device 11 to the string 2. And a power management PC 14 for control. Each of the power supply side GPS 13 and the power management PC 14 is connected to the power management device 11, and signals can be transmitted to and received from the power management device 11.

  The connection unit 8 is configured to combine the currents of the plurality of strings 2 into one and supply the combined currents to the power conditioner and the storage battery during power generation of the strings 2.

  The power management device 11 performs on / off control of the current supplied to the string 2. The power management device 11 obtains a GPS signal from the power supply side GPS 13 to synchronize with the camera 21. The power supply device 12 is connected to an external power supply, includes an AC / DC converter and the like, and supplies a direct current via the power management device 11.

  The power supply side GPS 13 is an antenna that receives radio waves from GPS satellites, and receives GPS signals for synchronization with the camera 21. The power supply side GPS 13 outputs the received GPS signal to the power supply management device 11. The power management PC 14 is a PC (for example, a notebook PC) for operating power management software used for inspection in the inspection system 1. The power management software can set the current and voltage supplied from the power management device 11 to the string 2 and their upper limit values by operating the power management PC 14 by the operator.

  The photographing unit 20 estimates the power generation efficiency of the camera 21 for photographing the block 3, the camera-side GPS 23 for the camera 21 to synchronize with the power management device 11, and the inspection target panel 4, and determines whether it is good or bad. An inspection management PC (arithmetic unit) 24 is provided. Each of the camera-side GPS 23 and the inspection management PC 24 is connected to the camera 21 so that signals can be transmitted to and received from the camera 21.

  The camera 21 is a high-sensitivity camera including a lens unit, an imaging unit including a CCD (Charge-Coupled Device), a transmission unit for transmitting an image signal, and the like. The camera 21 is, for example, a high resolution camera. The camera 21 can perform a gate operation and can adjust the gate time. The camera 21 may include a high speed shutter, for example. The camera 21 photographs the block 3 that emits light and a reference panel 16 described later in synchronization with the power supply to the string 2 of the power management device 11. The camera 21 outputs the captured image to the inspection management PC 24.

  The camera-side GPS 23 is an antenna that receives radio waves from GPS satellites, and receives GPS signals for synchronization with the power management device 11. The camera-side GPS 23 outputs the received GPS signal to the camera 21. The inspection management PC 24 is a PC (for example, a notebook PC) for operating panel inspection software used for inspection in the inspection system 1. The panel inspection software obtains a captured image of the inspection target panel 4 by operating the inspection management PC 24 by an operator, and performs predetermined image processing on the captured image, thereby determining whether the inspection target panel 4 is good or bad. Make a decision.

  In the inspection system 1 of the present embodiment, one reference panel 16 that serves as a reference for power generation efficiency of the inspection target panel 4 is used. The reference panel 16 is, for example, a silicon-based panel, but may be another type of panel. The reference panel 16 is, for example, a solar power generation panel configured with one cell. The reference panel 16 may be a photovoltaic power generation panel composed of a plurality of cells. The cell which comprises the reference | standard panel 16 is the same as the photovoltaic power generation cell 6 which comprises each photovoltaic power generation panel of the test object panel 4. FIG. The size of one reference panel 16 may be approximately the same as that of each photovoltaic power generation cell 6 constituting the inspection target panel 4 or may be smaller than the photovoltaic power generation cell 6. The size of the reference panel 16 may be, for example, about 1 / 60th the size of the inspection target panel 4. A plurality of reference panels 16 may be used.

  The power generation efficiency of the reference panel 16 is measured by a prescribed method in advance. That is, the power generation efficiency of the reference panel 16 is known. Here, the power generation efficiency is the ratio of light energy input to the photovoltaic power generation panel that is converted into electrical energy, and is so-called conversion efficiency.

  When the inspection target panel 4 is inspected and photographed, the reference panel 16 is electrically connected to the block 3 to be inspected including the inspection target panel 4, on the panel near the inspection target panel 4, around the inspection target panel 4, etc. Placed in. At this time, the block 3 to be inspected and the reference panel 16 fall within the viewing angle of the camera 21. In other words, the block 3 to be inspected and the reference panel 16 are arranged in the imaging region X of the camera 21.

  Then, with reference to FIG. 2 and FIG. 3, the test | inspection method of the photovoltaic power generation panel using the test | inspection system 1 is demonstrated. First, the reference panel 16 is connected to the string 2 and the power management device 11 (step S01; connection process). As shown in FIG. 1, the connection portion 8 and the plurality of blocks 3 are connected in series by connection lines L <b> 1 and L <b> 3 that are originally provided for solar power generation. Then, the connection line L2 that originally connects the block 3 to be inspected and the connection portion 8 is removed, and instead of this connection line L2, the block 3 to be inspected and the reference panel 16 are connected in series by the connection line L4. To do. The connection unit 8 and the reference panel 16 are connected by a connection line L5.

  Next, the power management software is started in the power management PC 14, and a current value, a voltage value, etc. are set by the power management software (step S02). In the present embodiment, a pulse current is supplied to the string 2 and the reference panel 16. In this step S02, the current value, pulse width, duty ratio, etc. of the pulse current supplied to the string 2 and the reference panel 16 are set.

  Next, panel inspection software is activated in the inspection management PC 24, and the camera 21 is installed (step S03). When the camera 21 is installed, the pan head is adjusted. Subsequently, in the panel inspection software, settings relating to photographing and settings relating to image processing are input (step S04). Here, settings such as the number of integrations, exposure, and brightness value are input.

  Next, the power supply device 12 and the power management device 11 supply power to the string 2 and the reference panel 16 (step S05; energization process). By supplying a predetermined pulse current to the string 2 and the reference panel 16, EL light emission occurs in each block 3 of the string 2 and the reference panel 16.

  Next, trial shooting before inspection is performed (step S06). By looking at the result of this trial shooting, the items set in the above steps S02 to S04 are finely adjusted.

  When the photographing condition adjustment in step S06 is completed, settings relating to panel recognition processing are input in the panel inspection software (step S07). Here, settings such as the number setting in one shooting range, the panel orientation setting (vertical or horizontal), the camera 21 pitch, the panel size, and the power generation amount (output) of the reference panel 16 are input. In the panel inspection software, the inspection range is manually input. This inspection range is a guideline for imaging the block 3 to be inspected, and is fixed during the imaging inspection. The inspection range corresponds to, for example, the imaging region X shown in FIG.

  Next, inspection imaging is performed (step S08). In the inspection imaging, the items set by the power management software and the panel inspection software in each procedure described above are not changed until the inspection is completed or interrupted. Further, the lens setting (aperture and zoom) of the camera 21 is not changed during the inspection.

  In the inspection imaging, each step shown in FIG. 3 is executed. First, block 3 is matched with the inspection range guideline on the panel inspection software screen. Next, the reference panel 16 is designated by manual input on the panel inspection software screen (step S11).

  Next, photographing is performed (step S12; photographing step). In step S12, the block 3 to be inspected and the reference panel 16 are photographed together. That is, imaging is performed so that the block 3 to be inspected and the reference panel 16 are contained in one image.

  Here, with reference to FIG. 4, the pulse current supplied in step S05 and the light emission amount of the inspection object panel 4 to which the pulse current is supplied will be described. As shown in FIG. 4A, in the energization process, a pulse current whose current value is changed stepwise is supplied to the string 2 and the reference panel 16. For example, like the current values C1 to C8, a pulse current (stepped pulse current) is supplied such that the current value increases by a certain amount with time (in time series). The maximum value of the pulse current supplied here is less than the rated current value. The duty ratio is a ratio corresponding to the rated current value. In practice, a pulse current whose current value increases stepwise as shown by the current values C <b> 1 to C <b> 8 is repeatedly supplied to the string 2 and the reference panel 16.

  On the other hand, in each inspection object panel 4 and the reference panel 16 of the block 3, light emission as shown in FIG. That is, light emission amounts P1 to P8 that increase stepwise are obtained corresponding to the current values C1 to C8. Further, between the light emission amounts P1 to P8, background light Poff detected while the pulse current is off is detected. This background light Poff is, for example, a constant value. In the photographing process, a plurality of images corresponding to the current values C1 to C8 and a plurality of images corresponding to the current values C1 to C8 are respectively acquired.

  As a result of the above photographing process, for example, an image P as shown in FIG. 5 is obtained. As FIG. 5 shows, the brightness | luminance differs for every photovoltaic power generation cell 6 which comprises the test object panel 4. FIG. The luminance in the image P is considered to be proportional to the light emission intensity of the solar power generation cell 6. Since there is a correlation between the light emission intensity of the solar power generation cell 6 and the power generation efficiency, the power generation efficiency of the solar power generation cell 6 can be estimated based on the luminance of the solar power generation cell 6 in the image P. it can. In particular, the image P includes an image portion of the reference panel 16 photographed at the same time. Since the power generation efficiency of the reference panel 16 is known, the power generation efficiency of the panel to be inspected 4 and each solar power generation cell 6 can be estimated based on the power generation efficiency of the reference panel 16. The power generation efficiency of the inspection target panel 4 may be estimated from the average value of the luminance of each photovoltaic power generation cell 6 constituting the inspection target panel 4.

  Subsequently, image processing is performed using panel inspection software (step S13). The processes after step S13 are automatically performed by the panel inspection software in the inspection management PC 24. In step S13, the image of the block 3 or the reference panel 16 is corrected, and the block 3 (inspection panel 4) or the reference panel 16 is recognized.

  Next, it is determined whether or not the image processing is successful (step S14). If it is determined in step S14 that the image processing has been successful, the power generation efficiency is determined (step S15). If it is determined in step S14 that the image processing has failed, the process returns to step S11, and the reference panel is designated again.

  When the power generation efficiency is “good”, the inspection imaging process is terminated. On the other hand, when the power generation efficiency is “No”, for example, “There is a panel 4 to be inspected that does not satisfy the judgment criteria. Do you want to re-shoot?” Or the like, a message confirming whether to re-shoot. Appears on the display. When performing re-photographing, the process returns to step S11, and the reference panel is designated again. And the determination result of the quality of power generation efficiency is displayed on a display (step S16).

  Specifically, the determination of whether the power generation efficiency is good in step S15 is performed as follows. The inspection management PC 24 calculates the light emission amounts P1 to P8 and Poff as shown in FIG. 4B based on the luminance of the image P shown in FIG. The inspection management PC 24 calculates the difference between the light emission amounts P1 to P8 when the pulse current is on and the light emission amount Poff when the pulse current is off. As a result, as shown in FIG. 6, pure light emission amounts D1 to D8 are obtained. Thereby, the current value-light emission amount characteristic of the inspection object panel 4 or each photovoltaic power generation cell 6 is obtained. For the reference panel 16 as well, a current value-light emission amount characteristic is obtained in the same manner.

  The inspection management PC 24 stores a predetermined current value supplied to the string 2 during operation of solar power generation and a threshold value of power generation efficiency required for the current value. The ratio of the current value-light emission amount characteristic of the panel to be inspected 4 or each photovoltaic power generation cell 6 to the current value-light emission amount characteristic of the reference panel 16 obtained as described above is obtained (comparison process). Then, by multiplying the power generation efficiency of the known reference panel 16 by the obtained ratio (comparison result), the power generation efficiency of the panel to be inspected 4 or each photovoltaic power generation cell 6 is quantitatively calculated (calculation process). . Here, each power generation efficiency corresponding to a change in the supplied current value may be calculated, or the power generation efficiency estimated for a predetermined current value may be obtained.

  And the quality of power generation efficiency is determined by whether or not the power generation efficiency of the panel to be inspected 4 or each photovoltaic power generation cell 6 calculated in the calculation process is equal to or higher than the above threshold value. By the above steps, the inspection is performed on the inspection object panel 4 or each photovoltaic power generation cell 6.

  According to the inspection system 1 and the inspection method using the inspection system 1 described above, the inspection object panel 4 and the reference panel 16 are connected in series, and a current is supplied to these panels by the power supply device 12. By this energization, the inspection object panel 4 and the reference panel 16 emit light. The inspection object panel 4 and the reference panel 16 that emit light are photographed together by the camera 21. One image P obtained by this photographing includes an image portion of the inspection object panel 4 that emits light and an image portion of the reference panel 16 that emits light. Since there is a correlation between the light emission intensity of the photovoltaic power generation panel (or photovoltaic power generation cell) and the power generation efficiency, by comparing the luminance of these image portions, the inspection panel 4 with respect to the power generation efficiency of the reference panel 16 is compared. The ratio of power generation efficiency can be obtained. Since the power generation efficiency of the reference panel 16 is known, the power generation efficiency of the panel to be inspected 4 can be quantitatively calculated by the inspection management PC 24 based on the power generation efficiency. In this inspection system 1, since the inspection object panel 4 and the reference panel 16 are imaged together, the imaging conditions of the reference panel 16 and the imaging conditions of the inspection object panel 4 are the same. Therefore, when the inspection management PC 24 compares the image portions, the influence of the external environment is offset and the influence is not easily received. Therefore, even when the external environment changes, a highly accurate inspection is realized. As a result, it is possible to easily determine the quality (for example, the degree of deterioration) of the solar power generation panel in use at a power plant or the like. Further, since it is only necessary to connect the reference panel 16 to the inspection target panel 4, it is not necessary to remove the inspection target panel 4 from the power plant, the maintenance cost can be reduced, and loss of opportunity for power generation can be prevented. .

  Conventional inspection methods include IV characteristics and EL image methods, but are not applicable to maintenance and inspection when a solar power generation apparatus is installed outdoors. Outdoor maintenance and inspection (especially on-site maintenance and inspection at power plants) has not been established. According to the inspection system 1, it is possible to reliably and easily determine whether the inspection target panel 4 is good or bad.

  Further, in the energization process, since a pulse current is supplied to the inspection object panel 4 and the reference panel 16, the difference between the light emission amounts P1 to P8 when the current is on and the light emission amount Poff when the current is off is obtained. Easy to cancel the background light. The S / N ratio (Signal-Noise ratio) is improved by canceling the background light.

  In the energization process, a pulse current whose current value is changed stepwise is supplied to the inspection object panel 4 and the reference panel 16, so that the current-luminescence characteristics can be acquired (see FIG. 6). Thereby, it is possible to clearly determine the degree of deterioration of the inspection object panel 4.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to said embodiment. For example, as shown in FIG. 7A, the pulse current may be supplied in another pattern, or as shown in FIG. 7B, the camera settings in the photographing process may be changed. .

  For example, as shown in FIG. 7A, in the energization process, a pulse current may be supplied with a current value that is equal to or higher than the ratings of the inspection object panel 4 and the reference panel 16. In this case, for example, the pulse current may be supplied at a current value about 5 to 10 times the rated current value la. The upper limit current value lb can be appropriately set in consideration of the performance of the inspection object panel 4 and the reference panel 16. In this case, it is desirable to reduce the duty ratio (that is, the time width) in accordance with the magnification with respect to the rated current value la. The duty ratio here is smaller than the duty ratio corresponding to the rated current value shown in FIG. The duty ratio is, for example, less than 50%. By adopting such an energization process, it becomes easy to eliminate the influence of background light (for example, sunlight or lighting).

  For example, as shown in FIG. 7B, in the imaging process, imaging may be performed with a gate time wider than the time width of the pulse current in the energization process. In this case, the gate operation of the camera 21 or the high-speed shutter is adjusted so as to synchronize with the light emission periods of the inspection object panel 4 and the reference panel 16. The gate time tc of the camera 21 is set to the minimum time including the time width tb of the pulse current. For example, when the time width tb of the pulse current is 125 ms, the gate time tc can be made slightly larger than the time width tb to be about 130 ms. Thereby, the time width for detecting the background light is minimized, and the influence of the background light Poff can be minimized.

  In the above-described embodiment, the case where the pulse current is supplied such that the current value increases by a constant amount in time series has been described. However, the pulse current in which the current value decreases by a constant amount in time series is supplied. Also good.

  The present invention is not limited to the case of supplying a pulse current to the inspection object panel 4 and the reference panel 16, and for example, a current that changes in a sine wave shape may be supplied. A constant current may be supplied to the inspection object panel 4 and the reference panel 16.

  In the above-described embodiment, the case where the inspection is performed using the camera 21 that is a high-resolution camera has been described, but the high-resolution camera may not be used. Even when a camera with a relatively low resolution is used, the luminance of the inspection object panel 4 can be obtained based on the obtained image, and the inspection object panel 4 can be inspected with high accuracy. In this case, the inspection object panel 4 is a photovoltaic power generation panel configured by a plurality of cells. Moreover, the brightness | luminance of the test object panel 4 is corresponded to the average value of the brightness | luminance of each photovoltaic power generation cell 6. FIG.

1 Inspection system (inspection system for photovoltaic panels)
2 String 3 Block 4 Panel to be inspected (power generation unit)
6 Solar power generation cell (power generation unit)
10 Power Supply Unit 12 Power Supply Device 14 Power Management PC
16 Reference panel 20 Imaging unit 21 Camera 24 Inspection management PC (calculation unit)

Claims (6)

An inspection method for inspecting a power generation unit that is a photovoltaic panel or photovoltaic cell,
A connection step of electrically connecting a reference panel, which is a photovoltaic power generation panel having a known power generation efficiency, in series to the power generation unit,
An energization step of supplying current to the power generation unit and the reference panel;
A photographing step of photographing the power generation unit and the reference panel that emit light in the energization step together using a camera;
A comparison step of comparing the luminance of the image portion of the power generation unit and the luminance of the image portion of the reference panel in one image obtained in the photographing step;
A calculation step of calculating the power generation efficiency of the power generation unit based on the comparison result obtained in the comparison step and the power generation efficiency of the reference panel,
Including an inspection method.   The inspection method according to claim 1, wherein in the energization step, a pulse current is supplied to the power generation unit and the reference panel.   The inspection method according to claim 2, wherein, in the energization step, the pulse current whose current value is changed stepwise is supplied to the power generation unit and the reference panel.   The inspection method according to claim 2 or 3, wherein, in the energization step, the pulse current is supplied at a current value equal to or higher than a rating of the power generation unit and the reference panel.   The inspection method according to any one of claims 2 to 4, wherein in the imaging step, imaging is performed with a gate time wider than a time width of the pulse current in the energization step. An inspection system for inspecting a power generation unit that is a photovoltaic panel or photovoltaic cell,
A reference panel that is electrically connected to the power generation unit in series and has a known power generation efficiency,
A power supply device for supplying current to the power generation unit and the reference panel;
A camera for photographing together the power generation unit that emits light when supplied with current by the power supply device, and the reference panel;
In one image taken by the camera, the brightness of the image portion of the power generation unit and the brightness of the image portion of the reference panel are compared, and based on the comparison result and the power generation efficiency of the reference panel, A calculation unit for calculating the power generation efficiency of the power generation unit;
An inspection system comprising:

Images