A portable photovoltaic module inspection device and method

Abstract

The application discloses a portable photovoltaic module detection device and method, and belongs to the technical field of photovoltaic detection. The device comprises an energy storage unit configured to provide instantaneous large-current pulse discharge and continuous load power supply; a test module electrically connected with the energy storage unit and configured to perform electroluminescence imaging test and power characteristic test on the photovoltaic module; an image acquisition unit configured to acquire the luminescence image of the photovoltaic module in the electroluminescence imaging test; a control unit in communication connection with the energy storage unit, the test module and the image acquisition unit and configured to coordinate the discharge timing of the energy storage unit to cooperate with the electroluminescence imaging test and the power characteristic test; and a portable support structure for bearing the energy storage unit, the test module and the control unit. The application solves the problem of lack of stable power supply and instantaneous large-current demand of EL test in outdoor field, realizes high integration and portability of the device, and improves the detection efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic testing equipment technology, and in particular to a portable photovoltaic module testing device and method. Background Technology

[0002] With the rapid development of the photovoltaic industry, the demand for operation and maintenance of photovoltaic power plants is increasing. During transportation, installation, and long-term outdoor operation, photovoltaic modules may develop defects such as microcracks, grid breaks, potential-induced degradation (PID) effects, and power attenuation, requiring regular inspection. Existing inspection solutions typically use electroluminescence (EL) detectors and power (IV) testers for separate testing. However, existing testing equipment is usually large and heavy, and the EL and power testing equipment are independent. Maintenance personnel must carry multiple devices when conducting on-site outdoor inspections, leading to cumbersome operation and low efficiency. Furthermore, stable mains power is often lacking in outdoor environments. Traditional power supply methods such as diesel generators suffer from high noise levels, vibration affecting image quality, and are difficult to transport. Ordinary lithium battery packs experience severe range degradation in low-temperature environments and cannot meet the instantaneous high-current pulse discharge requirements of EL testing, resulting in unstable image quality. Therefore, achieving highly integrated and portable photovoltaic module testing equipment, along with stable power supply in outdoor environments, is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] One of the objectives of this application is to provide a portable photovoltaic module testing device and method to address the problems of bulky equipment, limited functionality, and difficulty in obtaining outdoor power supply in the prior art, which leads to low testing efficiency and unstable imaging quality.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows: a portable photovoltaic module testing device and method, comprising a portable support structure, which includes a movable base and a control cabinet. The movable base is disposed at the bottom of the control cabinet and is used to control the movement of the entire control cabinet. The control cabinet includes: Energy storage unit, which is used to provide instantaneous high-current pulse discharge and continuous load power supply; The test module, which is electrically connected to the energy storage unit, is used to perform electroluminescence imaging tests and power characteristic tests on the photovoltaic module; The control unit is communicatively connected to the energy storage unit, the test module, and the image acquisition unit, and is used to coordinate the discharge timing of the energy storage unit to cooperate with the electroluminescence imaging test and the power characteristic test. The detection device is externally connected to the image acquisition unit via wired or wireless means, and the image acquisition unit is connected to the control cabinet in a split or quick-release structure.

[0005] The above solution solves the problems of lack of stable power supply and instantaneous high current demand for EL testing by setting up an energy storage unit to provide instantaneous high current pulse discharge and continuous load power supply, and coordinates the discharge timing with the control unit. At the same time, the portable support structure realizes the integration and portability of the equipment, and improves the testing efficiency.

[0006] In one implementation, the energy storage unit includes a supercapacitor module configured to provide millisecond-level high-current pulse discharge during the electroluminescence imaging test phase and to provide a stable scanning voltage during the power characteristic test phase.

[0007] The above solution utilizes the low internal resistance and high power density characteristics of supercapacitor modules to provide millisecond-level large current pulses with minimal voltage drop during the EL testing phase, ensuring the uniformity of EL image brightness while supporting continuous loads for power testing. This achieves adaptive matching of a single energy storage unit to two drastically different load characteristics.

[0008] As one implementation, the supercapacitor module includes: Supercapacitor cell assembly; A DC-DC converter is electrically connected to the supercapacitor cell group and is configured to regulate the input and output voltages. The equalization circuit, together with the supercapacitor cell group, is configured to balance the voltage of each supercapacitor cell; The charge / discharge management circuit is electrically connected to the supercapacitor cell group and the DC-DC converter, and is configured to control the charging current and the discharging current.

[0009] The above solution, through equalization circuits and charge / discharge management circuits, ensures the safety and stability of the supercapacitor module during frequent charge / discharge cycles, and extends its service life.

[0010] As one implementation method, the test module includes: An electroluminescence testing unit, electrically connected to the energy storage unit, is configured to apply a forward bias current to the photovoltaic module to excite luminescence; The power testing unit is electrically connected to the energy storage unit and is configured to scan the current-voltage characteristic curve of the photovoltaic module.

[0011] The above solution integrates the EL test unit and the power test unit into one unit, sharing the same energy storage unit, achieving "one wiring, two tests", and simplifying the operation process.

[0012] In one implementation, the electroluminescence testing unit includes a programmable DC power supply or a first electronic load, configured to apply a forward bias current to the photovoltaic module based on the discharge of the energy storage unit; The power testing unit includes a second electronic load, an irradiance sensor, and a temperature sensor. The second electronic load is configured to scan the current-voltage characteristic curve of the photovoltaic module, and the irradiance sensor and the temperature sensor are configured to collect environmental parameters to correct the power test results.

[0013] The above solution improves the accuracy of power test results by collecting environmental parameters through sensors.

[0014] In one implementation, the control unit executes the following control timing sequence: Control the energy storage unit to perform pre-charging; Upon completion of pre-charging, the test module should be triggered to inject electroluminescence test current into the photovoltaic module; In response to the injection of the electroluminescence test current, the image acquisition unit is triggered to perform exposure and image acquisition; In response to the completion of image acquisition, the test module is controlled to perform a power characteristic test.

[0015] The above solution automatically coordinates the timing of light source triggering, camera exposure, and electronic load through software algorithms, thereby achieving an automated testing process and further improving testing efficiency.

[0016] In one implementation, the control unit is further configured to: Multiple partial images acquired by the image acquisition unit are stitched together to generate a complete electroluminescent image of the photovoltaic module. Based on the grayscale distribution characteristics of the complete electroluminescent image, the defect type and defect level of the photovoltaic module are identified. The defect type includes at least one of microcracks, grid breaks, black spots, or potential-induced degradation effects.

[0017] The above solution enables automatic identification and classification of defects, reducing the difficulty of manual interpretation.

[0018] As one implementation, the detection device also includes a portable light-shielding component for covering the photovoltaic module in outdoor lighting conditions to isolate ambient light interference and provide a darkroom environment for the electroluminescence imaging test.

[0019] The above solution enables the device to perform EL testing outdoors during the day, expanding its application scenarios.

[0020] This invention provides another technical solution, which is a detection method for a portable photovoltaic module testing device, comprising the following steps: Step 1: The control unit detects the current voltage status of the energy storage unit. If the voltage is insufficient, it controls the charge and discharge management circuit to quickly charge the supercapacitor cells. Step 2: In response to the completion of pre-charging, the trigger test module injects electroluminescence test current into the photovoltaic module. When the voltage of the energy storage unit reaches the preset operating voltage threshold, the control unit sends a trigger signal to the electroluminescence test unit. The electroluminescence test unit then applies a forward bias current to the photovoltaic module based on the discharge of the energy storage unit. At this time, the charge carriers inside the photovoltaic module recombine and emit near-infrared light. The control unit ensures that the photovoltaic module is in the best luminescence state by precisely controlling the start time and duration of the current injection. Step 3: In response to the injection of the electroluminescence test current, the image acquisition unit is triggered to perform exposure and image acquisition. At a specific moment after the current injection and stabilization (usually a millisecond delay after the start of current injection), the control unit sends a synchronization trigger signal to the image acquisition unit. Upon receiving the signal, the image acquisition unit immediately opens the shutter to perform exposure. Step 4: In response to the completion of image acquisition, the control test module performs a power characteristic test. After the image acquisition unit 30 completes the image capture and transmits the data back to the control unit 10, the control unit immediately switches the test mode. At this time, the electroluminescence test unit stops working, the power test unit is activated, and the control unit controls the energy storage unit to switch to continuous power supply mode, supporting the second electronic load in the power test unit to scan the current-voltage (IV) characteristic curve of the photovoltaic module.

[0021] The above method supports a dual-mode testing process through a single energy storage unit, achieving efficient comprehensive diagnosis in outdoor environments.

[0022] Compared with the prior art, the beneficial effects of this application are as follows: The portable photovoltaic module testing device and method provided by this invention uses a supercapacitor module as the core energy storage unit. Taking advantage of its fast charging and discharging speed, long cycle life, and good low-temperature performance, it replaces traditional batteries or generators. The low internal resistance of the supercapacitor module can meet the instantaneous (millisecond level) high current discharge requirements of EL testing, ensuring the uniformity of EL image brightness and imaging quality, while also supporting the continuous load of power testing. The device integrates the EL imaging system and the IV characteristic testing system on the same control cabinet and mobile bracket, realizing "one wiring, two tests", which greatly improves the operation and maintenance efficiency. The modular portable design, combined with the mobile base, adapts to complex outdoor terrain and solves the problems of bulky and difficult transportation of existing equipment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall main structure of the portable photovoltaic module testing device of the present invention.

[0024] Figure 2 This is a side view of the overall structure of the portable photovoltaic module testing device of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the portable light-shielding component of the portable photovoltaic module testing device of the present invention.

[0026] Figure 4 This is a schematic diagram of the overall open side view of the portable photovoltaic module testing device of the present invention.

[0027] Figure 5 This is a top view of the overall open structure of the portable photovoltaic module testing device of the present invention.

[0028] Figure 6 This is a schematic diagram of the circuit topology of the portable photovoltaic module testing device of the present invention.

[0029] In the diagram: 10. Energy storage unit; 11. Supercapacitor cell group; 12. DC-DC converter; 13. Equalization circuit; 14. Charge and discharge management circuit; 20. Test module; 21. Electroluminescence test unit; 22. Power test unit; 30. Image acquisition unit; 40. Control unit; 50. Portable support structure; 51. Mobile base; 52. Control cabinet; 60. Portable light shielding component. Detailed Implementation

[0030] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0031] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0032] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0034] Example 1: One preferred embodiment of this application, such as Figures 1 to 6 As shown, a portable photovoltaic module testing device includes a portable support structure 50, which includes a movable base 51 and a control cabinet 52. The movable base 51 is located at the bottom of the control cabinet 52 and is used to control the movement of the entire control cabinet 52. Specifically, the movable base 51 of the portable support structure 50 can be designed as a trolley-type base with wheels, or a foldable bracket structure. The energy storage unit 10, the test module 20, and the control unit 40 are all integrated and installed inside or on the surface of the control cabinet 52. This structural design makes the device lightweight and compact, allowing maintenance personnel to move the device easily like dragging a suitcase, adapting to the testing needs of complex terrains such as mountains and rooftops. The mobile base 51 can be designed as a box structure with wheels and a pull rod, similar to a suitcase, or as a flatbed trolley structure with casters. The control cabinet 52, as the core load-bearing component, internally houses the energy storage unit 10, test module 20, and control unit 40 via partitions or brackets. Externally, it features an operation panel, wiring ports, and ventilation holes. This integrated design consolidates the previously dispersed power supply, load, and control equipment into a single unit. Maintenance personnel can easily move the equipment by dragging the mobile base 51, greatly reducing the difficulty of transporting it in complex outdoor terrain and solving the transportation problems caused by the bulkiness and separation of traditional testing equipment. The control cabinet 52 includes: The energy storage unit 10 is used to provide instantaneous high-current pulse discharge and continuous load power supply. Specifically, the energy storage unit 10 is the core energy source of the entire device. It integrates a high-power-density energy storage medium and related management circuits. During the electroluminescence (EL) imaging test, the photovoltaic module needs an instantaneous (usually millisecond to second-level) high current injection to excite near-infrared light. The energy storage unit 10 can respond to this demand and release an instantaneous high-current pulse. During the power characteristic test, the device needs a continuous and stable voltage output to complete the scanning of the current-voltage (IV) curve. The energy storage unit 10 can also provide continuous load power supply. This embodiment solves the problem of lack of stable mains power supply in outdoor sites through the dual-function configuration of the energy storage unit 10. At the same time, it overcomes the technical bottleneck of traditional lithium batteries having high internal resistance and difficulty in supporting instantaneous high-current discharge, which leads to severe voltage drop. It realizes the passive and portable operation of the device. The test module 20, which is electrically connected to the energy storage unit 10, is used to perform electroluminescence imaging tests and power characteristic tests on photovoltaic modules. Specifically, the test module 20 is integrated inside the device, and its input terminal is electrically connected to the output terminal of the energy storage unit 10 to obtain the electrical energy required for operation. The test module 20 integrates two sets of functional circuits: one set is used to generate the excitation current required for EL testing, and the other set is used to simulate electronic loads for IV scanning. This integrated design allows maintenance personnel to complete both tests with only one wiring without having to carry separate EL testers and power testers, which greatly improves the efficiency of on-site testing. The control unit 40 is communicatively connected to the energy storage unit 10, the test module 20, and the image acquisition unit 30. It is used to coordinate the discharge timing of the energy storage unit 10 to cooperate with electroluminescence imaging testing and power characteristic testing. Specifically, the control unit 40, as the "brain" of the device, is usually implemented using an embedded industrial computer or a high-performance microcontroller. It has a preset automatic control program that can precisely control the switching of the charging and discharging states of the energy storage unit 10. For example, during EL testing, the control unit 40 controls the energy storage unit 10 to output a large current pulse and simultaneously triggers the image acquisition unit 30 to expose. After the EL test is completed, the control unit 40 immediately adjusts the output mode of the energy storage unit 10 to adapt to the continuous voltage output required for power testing. This timing coordination mechanism ensures that a single energy storage unit 10 can stably and efficiently support two completely different test modes, avoiding energy waste and equipment conflicts. The external communication of the detection device with the image acquisition unit 30 is via wired or wireless means. The image acquisition unit 30 and the control cabinet 52 are connected by a split or quick-release structure. Specifically, the image acquisition unit 30 usually uses a high-sensitivity near-infrared camera and is equipped with a filter to filter out ambient light interference. Under the trigger of the control unit 40, the image acquisition unit 30 performs exposure and shooting at the moment when the photovoltaic module is powered on and emits light to obtain defect images inside the module. The image acquisition unit 30 can transmit the acquired image data to the control unit 40 for processing via wired (such as USB, Ethernet) or wireless (such as Wi-Fi, Bluetooth) means.

[0035] The portable photovoltaic module testing device provided in this embodiment provides instantaneous high-current pulse discharge and continuous load power supply through the energy storage unit 10, and coordinates the discharge timing with the control unit 40, which solves the problems of lack of stable power supply at outdoor sites and instantaneous high-current requirements of EL testing. At the same time, the portable support structure 50 realizes the integration and portability of the device, which significantly improves the efficiency and quality of on-site testing of photovoltaic modules.

[0036] Example 2: This embodiment, based on Embodiment 1, provides a detailed description of the specific structure and working principle of the energy storage unit 10. For example... Figure 6 As shown, the energy storage unit 10 includes a supercapacitor module, which is configured to provide millisecond-level high-current pulse discharge during the electroluminescence imaging test phase and to provide a stable scanning voltage during the power characteristic test phase.

[0037] Specifically, the reason why this embodiment chooses a supercapacitor module as the core energy storage medium is a creative design based on the differentiated requirements of electroluminescence (EL) testing and power (IV) testing for power characteristics. In the EL testing stage, photovoltaic modules need to inject a large forward bias current (e.g., tens of amperes) instantaneously (usually in the millisecond to second range) to excite near-infrared light. If a traditional lithium battery pack is used, due to its relatively large internal resistance, the output voltage will drop sharply during the instant of high current discharge, resulting in unstable injection current and ultimately uneven brightness of the acquired EL image, which seriously affects defect interpretation. In addition, lithium batteries suffer from severe performance degradation at low temperatures, making them unsuitable for complex outdoor environments. If a diesel generator is used, there are problems such as bulky equipment, high noise, and vibration affecting image quality. In contrast, supercapacitor modules have extremely low internal resistance and extremely high power density, which can release huge currents in a very short time with minimal voltage drop, thereby ensuring the constant and stable EL test current and ensuring image quality. At the same time, supercapacitors have long cycle life and fast charging speed, which can support the continuous load requirements of the power test phase, perfectly matching the design goal of portable testing devices: "multi-purpose and passive for outdoor use". Furthermore, such as Figure 6 As shown, the supercapacitor module includes: Supercapacitor cell group 11; DC-DC converter 12 is electrically connected to supercapacitor cell group 11 and is configured to regulate input and output voltage; The equalization circuit 13, together with the supercapacitor cell group 11, is configured to balance the voltage of each supercapacitor cell. The charge / discharge management circuit 14 is electrically connected to the supercapacitor cell group 11 and the DC-DC converter 12, and is configured to control the charging current and the discharging current.

[0038] This embodiment achieves adaptive matching of a single energy storage unit 10 to two drastically different load characteristics through the coordinated operation of the circuit topology described above. In the EL test scenario, the charge and discharge management circuit 14 responds to the control command and controls the supercapacitor cell group 11 to release a large current instantaneously. The DC-DC converter 12 responds quickly to maintain voltage stability, ensuring that the current pulse injected into the photovoltaic module has extremely high rise edge steepness and top flatness, thereby obtaining high-quality EL images. In the power test scenario, the circuit switches to continuous power supply mode to support the electronic load to complete the full IV curve scan. This design not only solves the outdoor power supply problem, but also improves the accuracy and reliability of the test data from the source of the power supply.

[0039] Example 3: This embodiment, based on the above embodiments, provides a detailed description of the specific structure of the test module 20 and its cooperative working principle with the energy storage unit 10. For example... Figure 6 As shown, the test module 20 includes an electroluminescence test unit 21, which is electrically connected to the energy storage unit 10 and configured to apply a forward bias current to the photovoltaic module to excite light emission; and a power test unit 22, which is electrically connected to the energy storage unit 10 and configured to scan the current-voltage characteristic curve of the photovoltaic module.

[0040] Specifically, one of the core innovations of this embodiment lies in the realization of an integrated architecture of "one wiring, two tests". In the traditional testing mode, the EL tester and the IV tester are usually two separate devices that need to be connected to the positive and negative terminals of the photovoltaic module respectively. This is cumbersome and requires two independent power supply systems. In this embodiment, the electroluminescence testing unit 21 and the power testing unit 22 are integrated into the same testing module 20, and both are electrically connected to the same energy storage unit 10. This means that both the instantaneous high current required for EL testing and the continuous scanning voltage required for power testing are supplied uniformly by the energy storage unit 10. This design not only reduces the size and weight of the equipment, but also avoids the operational risks caused by repeated wiring on site, significantly improving testing efficiency.

[0041] Furthermore, the electroluminescence testing unit 21 includes a programmable DC power supply or a first electronic load, configured to apply a forward bias current to the photovoltaic module based on the discharge of the energy storage unit 10. In EL test mode, the electroluminescence testing unit 21 operates in constant current source mode or current-pull mode of the electronic load. The electrical energy provided by the energy storage unit 10 is regulated by the electroluminescence testing unit 21 and converted into a constant current (e.g., 0.8 times Isc) that meets the test standard requirements and is injected into the photovoltaic module to excite the recombination of charge carriers inside the module to emit light. Since the energy storage unit 10 has the characteristics of low internal resistance and high power density, even at the moment of injecting a large current, the electroluminescence testing unit 21 can obtain a stable input voltage, thereby ensuring the stability of the output current, preventing current fluctuations caused by voltage drops, and ensuring imaging quality. The power test unit 22 includes a second electronic load, an irradiance sensor, and a temperature sensor. The second electronic load is configured to scan the current-voltage characteristic curve of the photovoltaic module. The irradiance sensor and temperature sensor are configured to collect environmental parameters to correct the power test results. In the power test mode, the second electronic load operates in a variable load mode and scans the complete IV curve of the photovoltaic module from open-circuit voltage to short-circuit current by rapidly changing the internal impedance. It is worth noting that the environmental conditions in the outdoor field are complex and variable. Fluctuations in irradiance and temperature will directly affect the output characteristics of the photovoltaic module. If only the original IV curve is measured, the data will lack comparability. Therefore, this embodiment introduces an irradiance sensor and a temperature sensor. The irradiance sensor monitors the light intensity irradiating the surface of the photovoltaic module in real time, while the temperature sensor is attached to the back panel of the module to collect temperature data. The control unit 40 receives these environmental parameters and corrects the measured IV curve to standard test conditions (STC, such as 1000W / m², 25℃) according to a standard correction algorithm (such as IEC 60891 standard), thereby eliminating the interference of environmental factors and outputting accurate power parameters. This design, which combines hardware integration with environmental perception correction, ensures that the device can still provide high-precision detection data in complex outdoor environments.

[0042] Example 4: Based on the above embodiments, this embodiment provides a detailed description of the coordinated control timing of the control unit 40. The control unit 40 executes the following control timing sequence: controlling the energy storage unit 10 to perform pre-charging; upon completion of pre-charging, triggering the test module 20 to inject electroluminescence test current into the photovoltaic module; in response to the injection of electroluminescence test current, triggering the image acquisition unit 30 to perform exposure and image acquisition; in response to completion of image acquisition, controlling the test module 20 to perform power characteristic testing. Specifically, this embodiment uses software algorithms to materialize hardware actions into a precise time sequence, realizing an automated testing process with "one-click start". The control unit 40 has preset synchronous control logic, the specific execution steps of which are as follows: Step S1: Control the energy storage unit 10 to perform pre-charging. Before the test starts, the control unit 40 detects the current voltage state of the energy storage unit 10. If the voltage is insufficient, the charge and discharge management circuit 14 controls the supercapacitor cell group 11 to perform rapid charging. This step is crucial because electroluminescence (EL) testing requires instantaneous large current pulses. If the energy storage unit 10 does not reach the predetermined voltage threshold, the injected current may become unstable due to excessive voltage drop during discharge, which will affect the imaging quality. The pre-charging process ensures that the energy storage unit 10 has sufficient energy reserves to prepare for the subsequent millisecond-level large current discharge.

[0043] Step S2: In response to the completion of pre-charging, the trigger test module 20 injects electroluminescence test current into the photovoltaic module. When the voltage of the energy storage unit 10 reaches the preset operating voltage threshold, the control unit 40 sends a trigger signal to the electroluminescence test unit 21. The electroluminescence test unit 21 then applies a forward bias current to the photovoltaic module based on the discharge of the energy storage unit 10. At this time, the charge carriers inside the photovoltaic module recombine and emit near-infrared light. The control unit 40 ensures that the photovoltaic module is in the best luminescence state by precisely controlling the start time and duration of the current injection.

[0044] Step S3: In response to the injection of the electroluminescence test current, the image acquisition unit 30 is triggered to perform exposure and image acquisition. At a specific moment after the current injection and stabilization (typically a millisecond delay after the start of current injection), the control unit 40 sends a synchronization trigger signal to the image acquisition unit 30. Upon receiving the signal, the image acquisition unit 30 immediately opens the shutter for exposure. This timing is extremely critical: if the exposure is too early, the module has not yet emitted sufficient light, resulting in a dark image; if the exposure is too late, the optimal light emission window may be missed or the module may overheat. In this embodiment, through precise synchronization by the control unit 40, the image acquisition unit 30 ensures that the image is captured during the period when the photovoltaic module's luminous intensity is highest and most stable, thereby obtaining a high signal-to-noise ratio EL image.

[0045] Step S4: In response to the completion of image acquisition, the control test module 20 performs a power characteristic test. After the image acquisition unit 30 completes the image capture and transmits the data back to the control unit 40, the control unit 40 immediately switches the test mode. At this time, the electroluminescence test unit 21 stops working, the power test unit 22 is activated, and the control unit 40 controls the energy storage unit 10 to switch to continuous power supply mode, supporting the second electronic load in the power test unit 22 to scan the current-voltage (IV) characteristic curve of the photovoltaic module. The power test is arranged after the EL test. On the one hand, the instantaneous large current required by the EL test may produce a small thermal effect on the module. Waiting a moment before performing the power test can avoid the influence of this thermal effect on the IV curve. On the other hand, this sequential arrangement is in line with the habits of on-site operation and maintenance. First, the EL image is used to visually determine whether there are internal defects in the module, and then the power test is used to quantify the performance degradation of the module.

[0046] This embodiment, through the rigorous design of the aforementioned timing logic, achieves orderly support for two distinctly different test modes from a single energy storage unit 10. The control unit 40, acting as the core scheduler, coordinates the precise cooperation of multiple actions such as energy release, current injection, optical acquisition, and load scanning. This not only avoids the tediousness and errors of manual operation but also ensures the synchronization and accuracy of test data at the system level.

[0047] Example 5: Based on the above embodiments, this embodiment provides a detailed description of the data processing function of the control unit 40. The control unit 40 is further configured to: stitch together multiple local images acquired by the image acquisition unit 30 to generate a complete electroluminescent image of the photovoltaic module; and identify the defect type and defect level of the photovoltaic module based on the grayscale distribution characteristics of the complete electroluminescent image. The defect type includes at least one of hidden cracks, broken grids, black spots, or potential-induced decay effects.

[0048] Specifically, for large-size photovoltaic modules or high-resolution imaging requirements, the image acquisition unit 30 often cannot cover the entire module surface with a single shot. Instead, it needs to acquire multiple partial images by moving the shooting position or adjusting the focal length. The image processing module integrated within the control unit 40 first extracts and matches feature points from the acquired partial images, calculates the overlapping area and displacement deviation between adjacent images, and then performs image registration and fusion operations to finally generate an electroluminescent image containing complete information about the module. This stitching processing function eliminates the tediousness and errors of manual stitching, ensuring the completeness and accuracy of subsequent defect identification.

[0049] In terms of defect identification, the control unit 40 uses a preset image recognition algorithm to analyze the stitched complete electroluminescent image. Since defects inside the photovoltaic module will exhibit specific grayscale distribution characteristics in the electroluminescent image, the control unit 40 extracts these features and compares them with a pre-stored defect sample library to determine the defect type. For example, microcracks usually appear as thin line-shaped dark areas, broken grids appear as thin black stripes perpendicular to the main grid lines, black spots appear as local irregular dark spots, and potential-induced degradation (PID) effect usually appears as overall darkening of the module edge area. The control unit 40 can not only identify the above defect types, but also classify the severity of defects according to parameters such as the area ratio of the defect area and grayscale contrast, such as classifying them into minor, moderate, and severe levels. This intelligent image processing and defect identification function greatly reduces the reliance on the professional experience of operation and maintenance personnel, improves the objectivity and standardization of detection results, and provides accurate data support for the operation and maintenance decisions of photovoltaic power plants. Furthermore, the device provided in this embodiment also includes a portable light-shielding component 60, which is used to cover the photovoltaic module in outdoor lighting conditions to isolate ambient light interference and provide a darkroom environment for electroluminescence imaging testing. Specifically, the principle of electroluminescence (EL) testing is to use a near-infrared camera to capture the weak light signal emitted from inside the module. If the test is conducted outdoors during the day, strong ambient light (especially strong sunlight in the near-infrared band) will completely overwhelm the light emission signal of the module, resulting in imaging failure. Traditional solutions can usually only conduct outdoor EL testing at night, which severely limits the maintenance time window. This embodiment creatively solves this problem by introducing the portable light-shielding component 60. The portable light-shielding component 60 can be designed as a folding tent, a telescopic light-shielding cover, or a flexible light-shielding fabric structure. Its interior is coated with light-absorbing material (such as black velvet), which can effectively block external light. During testing, maintenance personnel only need to quickly unfold the portable light-shielding component 60 and cover it on the photovoltaic module under test to create a temporary "dark room" in strong outdoor light conditions. This makes EL testing no longer limited by day and night, significantly expanding the adaptability of the device's application scenarios and improving maintenance efficiency. In this embodiment, through the cooperation of the above-mentioned mechanical structure and light-shielding component, the device achieves high integration, portability, and all-weather operation capability.

[0050] Example 6: This embodiment provides a testing method for a photovoltaic module testing device. This method utilizes an energy storage unit 10 to simultaneously support electroluminescence imaging testing and power characteristic testing. This method can be executed by any of the portable photovoltaic module testing devices described in Embodiments 1 to 5 above, and is particularly completed by the control unit 40 coordinating the various hardware modules. Specifically, the method includes the following steps: Step 1: Pre-charging the energy storage unit 10. Before the test begins, the control unit 40 detects the current voltage state of the energy storage unit 10. If the voltage is insufficient, the charge / discharge management circuit 14 controls the supercapacitor cell group 11 to charge rapidly. This step is crucial because electroluminescence imaging testing requires instantaneous large current pulses. If the energy storage unit 10 does not reach the predetermined voltage threshold, the injected current may become unstable due to excessive voltage drop during discharge, thus affecting the imaging quality. The pre-charging process ensures that the energy storage unit 10 has sufficient energy reserves to prepare for the subsequent millisecond-level large current discharge. Step 2: Based on the discharge of the energy storage unit 10, a forward bias current is applied to the photovoltaic module to excite light emission, and the light emission image of the photovoltaic module is acquired. When the voltage of the energy storage unit 10 reaches the preset working voltage threshold, the control unit 40 triggers the electroluminescence test unit 21 in the test module 20 to work. The electrical energy released by the energy storage unit 10 is regulated and converted into a constant current that meets the test standard requirements and injected into the photovoltaic module. At this time, the charge carriers inside the photovoltaic module recombine and emit near-infrared light. At the same time, the control unit 40 synchronously triggers the image acquisition unit 30 to perform exposure and shooting to obtain the defect image inside the module. It should be understood that the low internal resistance characteristic of the energy storage unit 10 plays a key role in this step. It ensures that the output voltage remains stable at the moment of injection of large current, thereby ensuring the uniformity of light emission brightness. Step 3: In response to the completion of the light emission image acquisition, based on the discharge of the energy storage unit 10, a power characteristic scan of the photovoltaic module is performed. After the image acquisition unit 30 completes the image capture and transmits the data back to the control unit 10, the control unit 10 immediately switches the test mode. At this time, the electroluminescence test unit 21 stops working, the power test unit 22 is activated, and the energy storage unit 10 continues to provide power to support the electronic load in the power test unit 22 to scan the current-voltage characteristic curve of the photovoltaic module. In this embodiment, the power test is arranged after the electroluminescence imaging test. On the one hand, the instantaneous large current required for the electroluminescence test may produce a small thermal effect on the module. Waiting a moment before performing the power test can avoid the influence of this thermal effect on the current-voltage curve. On the other hand, this sequential arrangement is in line with the habits of on-site operation and maintenance. First, the image is used to visually determine whether there are internal defects in the module, and then the power test is used to quantify the performance degradation of the module.

[0051] The photovoltaic module testing method provided in this embodiment supports a dual-mode testing process through a single energy storage unit, achieving efficient comprehensive diagnosis in outdoor environments. This method fully utilizes the high power density and low internal resistance characteristics of the energy storage unit, solving the problem that traditional power supply methods cannot simultaneously meet the demands of instantaneous high current and continuous load, and significantly improving testing efficiency and data.

[0052] Example 7: This embodiment describes in detail the actual application process of the portable photovoltaic module testing device provided by the present invention in a specific application scenario. The scenario is set as on-site operation and maintenance testing of a mountain photovoltaic power station. Due to the complex mountain terrain, photovoltaic modules are usually installed on slopes with large gradients, and there is a lack of mains power access on site, making it difficult for traditional testing equipment to enter or to work properly.

[0053] Maintenance personnel arrive at the site with the portable photovoltaic module testing device provided in this embodiment. The portable support structure 50 of the device is designed as a trolley box structure. The energy storage unit 10, the test module 20 and the control unit 40 are all integrated in the control cabinet 52. Maintenance personnel can easily drag the device to the vicinity of the photovoltaic module to be tested, just like dragging a suitcase. There is no need to carry heavy diesel generators or lithium battery packs, which greatly reduces labor costs and transportation difficulties.

[0054] Upon arrival at the test site, the maintenance personnel removed the image acquisition unit 30 from the control cabinet 52 using a quick-release mechanism and adjusted its shooting angle to face the photovoltaic module under test. Since the test was conducted during the day and the outdoor light intensity was high, direct electroluminescence (EL) imaging testing would be severely interfered with by ambient light. At this time, the maintenance personnel unfolded the portable light-shielding component 60 and covered the surface of the photovoltaic module under test to isolate the ambient light and create a temporary darkroom environment for EL testing. This operation enabled the device to perform high-quality EL imaging in strong daylight, breaking through the limitation that traditional EL testing can only be carried out at night and significantly expanding the time window for maintenance work.

[0055] After the wiring is completed, the maintenance personnel trigger the automated test process through the one-button start function of the control unit 40. The control unit 40 first controls the energy storage unit 10 to precharge. Since the energy storage unit 10 uses a supercapacitor module, its charging speed is extremely fast and it can reach the predetermined voltage threshold in a short time. Subsequently, the control unit 40 coordinates the discharge sequence and controls the energy storage unit 10 to release a large current pulse instantly. The forward bias current is injected into the photovoltaic module through the electroluminescence test unit 21. At the moment of current injection, the image acquisition unit 30 simultaneously exposes and acquires the luminous image of the photovoltaic module. Since the supercapacitor module has extremely low internal resistance, even during the millisecond-level large current pulse discharge process, the output voltage remains stable, ensuring the constant injection current. This results in the acquisition of a high signal-to-noise ratio and uniform brightness EL image, which clearly shows defects such as hidden cracks and broken grids inside the module.

[0056] After the EL test is completed, the control unit 40 immediately switches modes and controls the power test unit 22 to scan the current-voltage (IV) characteristic curve of the photovoltaic module. During this process, the energy storage unit 10 continues to provide a stable and continuous load power supply. The irradiance sensor and temperature sensor collect environmental parameters in real time. The control unit 40 corrects the scan results based on these parameters and outputs accurate power performance data. The entire test process does not require external mains power and is powered entirely by the energy storage unit 10. It also achieves "one connection, two tests", which greatly improves the testing efficiency.

[0057] After the test, the control unit 40 automatically stitches together the acquired EL images and identifies defects, and generates a comprehensive test report by combining the power test data. Maintenance personnel can upload the report to the cloud maintenance platform via wireless network or export it on-site for viewing. Compared with traditional testing methods that require carrying multiple devices, finding power sources, testing at night, or setting up complex shading facilities, the device provided in this embodiment can still efficiently and accurately complete the comprehensive diagnosis of photovoltaic modules in outdoor environments without network or electricity, fully verifying its significant advantages in portability, power supply stability, and testing efficiency.

[0058] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A portable photovoltaic module testing device, characterized in that, include: A portable support structure (50) includes a movable base and a control cabinet. The movable base (51) is located at the bottom of the control cabinet (52) and is used to control the movement of the entire control cabinet (52). The control cabinet (52) includes: Energy storage unit (10) is used to provide instantaneous high-current pulse discharge and continuous load power supply; The test module (20), which is electrically connected to the energy storage unit (10), is used to perform electroluminescence imaging test and power characteristic test on the photovoltaic module; The control unit (40) is communicatively connected to the energy storage unit (10), the test module (20) and the image acquisition unit (30), and is used to coordinate the discharge timing of the energy storage unit (10) to cooperate with the electroluminescence imaging test and the power characteristic test; The external part of the detection device is connected to the image acquisition unit (30) via wired or wireless means. The image acquisition unit (30) and the control cabinet (52) are connected by a split or quick-release structure.

2. The portable photovoltaic module testing device as described in claim 1, characterized in that: The energy storage unit (10) includes a supercapacitor module configured to provide millisecond-level high-current pulse discharge during the electroluminescence imaging test phase and to provide a stable scanning voltage during the power characteristic test phase.

3. The portable photovoltaic module testing device as described in claim 2, characterized in that: The supercapacitor module includes: Supercapacitor cell group (11); DC-DC converter (12) is electrically connected to the supercapacitor cell group (11) and configured to regulate input and output voltage; The equalization circuit (13), together with the supercapacitor cell group (11), is configured to balance the voltage of each supercapacitor cell; The charge / discharge management circuit (14) is electrically connected to the supercapacitor cell group (11) and the DC-DC converter (12) and is configured to control the charging current and the discharging current.

4. The portable photovoltaic module testing device as described in claim 1, characterized in that: The test module (20) includes: An electroluminescence testing unit (21) is electrically connected to the energy storage unit (10) and is configured to apply a forward bias current to the photovoltaic module to excite luminescence. The power test unit (22) is electrically connected to the energy storage unit (10) and is configured to scan the current-voltage characteristic curve of the photovoltaic module.

5. The portable photovoltaic module testing device as described in claim 4, characterized in that: The electroluminescence testing unit (21) includes a programmable DC power supply or a first electronic load, configured to apply a forward bias current to the photovoltaic module based on the discharge of the energy storage unit (10); The power test unit (22) includes a second electronic load, an irradiance sensor and a temperature sensor. The second electronic load is configured to scan the current-voltage characteristic curve of the photovoltaic module, and the irradiance sensor and the temperature sensor are configured to collect environmental parameters to correct the power test results.

6. The portable photovoltaic module testing device as described in claim 1, characterized in that: The control unit (40) executes the following control timing sequence: Control the energy storage unit (10) to perform pre-charging; Upon completion of pre-charging, the test module (20) should be triggered to inject electroluminescence test current into the photovoltaic module; In response to the injection of the electroluminescent test current, the image acquisition unit (30) is triggered to perform exposure and image acquisition; In response to the completion of image acquisition, the test module (20) is controlled to perform a power characteristic test.

7. The portable photovoltaic module testing device as described in claim 1, characterized in that: The control unit (40) is further configured to: Multiple local images acquired by the image acquisition unit (30) are stitched together to generate a complete electroluminescent image of the photovoltaic module; Based on the grayscale distribution characteristics of the complete electroluminescent image, the defect type and defect level of the photovoltaic module are identified. The defect type includes at least one of microcracks, grid breaks, black spots, or potential-induced degradation effects.

8. The portable photovoltaic module testing device as described in claim 1, characterized in that: The detection device also includes a portable light-shielding component (60) for covering the photovoltaic component in outdoor lighting conditions to isolate ambient light interference and provide a darkroom environment for the electroluminescence imaging test.

9. The detection method of the portable photovoltaic module testing device as described in claim 1, characterized in that: The steps include the following: Step 1: The control unit (40) detects the current voltage status of the energy storage unit (10). If the voltage is insufficient, it controls the charge and discharge management circuit (14) to quickly charge the supercapacitor cell group (11). Step 2: In response to the completion of pre-charging, the trigger test module (20) injects electroluminescence test current into the photovoltaic module. When the voltage of the energy storage unit (10) reaches the preset working voltage threshold, the control unit (40) sends a trigger signal to the electroluminescence test unit (21). The electroluminescence test unit (21) then applies a forward bias current to the photovoltaic module based on the discharge of the energy storage unit (10). At this time, the charge carriers inside the photovoltaic module recombine and emit near-infrared light. The control unit (40) ensures that the photovoltaic module is in the best luminescence state by precisely controlling the start time and duration of the current injection. Step 3: In response to the injection of the electroluminescence test current, the image acquisition unit (30) is triggered to perform exposure and image acquisition. At a specific moment after the current injection and stabilization (usually a millisecond delay after the start of current injection), the control unit (40) sends a synchronization trigger signal to the image acquisition unit (30), and the image acquisition unit (30) immediately opens the shutter to perform exposure upon receiving the signal; Step 4: In response to the completion of image acquisition, the control test module (20) performs power characteristic testing. After the image acquisition unit (30) completes the shooting and transmits the data back to the control unit (40), the control unit (40) immediately switches the test mode. At this time, the electroluminescence test unit (21) stops working, the power test unit (22) is activated, and the control unit (40) controls the energy storage unit (10) to switch to continuous power supply mode, supporting the second electronic load in the power test unit (22) to scan the current-voltage (IV) characteristic curve of the photovoltaic module.

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