Photovoltaic module measuring device and photovoltaic system

Abstract

The utility model relates to a photovoltaic module measuring device and a photovoltaic system. In the photovoltaic module measuring device, a plurality of first ends of a switching module are connected with a plurality of photovoltaic modules in a one-to-one correspondence manner, an input end of a measuring instrument is connected with a second end of the switching module, an output end of the measuring instrument is used for being connected with a rear-end circuit of a photovoltaic system, and an input end of a control system is connected with the output end of the measuring instrument, and the switching module conducts each photovoltaic module and the measuring instrument in a time-sharing manner. On-line measurement of multiple groups of photovoltaic modules is realized by sharing the same measuring instrument, and the accuracy of a test result during comparison test of the multiple groups of photovoltaic modules is improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic measurement technology, and in particular to a photovoltaic module measurement device and a photovoltaic system. Background Technology

[0002] The power generation performance of photovoltaic modules is one of the important indicators of photovoltaic module technology. In addition to higher power, high-efficiency modules should also have higher power generation.

[0003] Electricity meters are typically used to measure the power generation performance of photovoltaic (PV) modules. However, the applicant discovered that regardless of the meter's design accuracy, random or systematic accuracy fluctuations and malfunctions can occur in actual use. Traditional solutions connect two PV modules to their respective electricity meters. When the two meters malfunction, experience accuracy fluctuations, or have inconsistent accuracy ranges at different times, the cumulative meter readings cannot accurately reflect the power generation of the two PV modules during the same period, resulting in low accuracy in outdoor comparative testing of PV modules. Utility Model Content

[0004] Therefore, it is necessary to provide a photovoltaic module measurement device and photovoltaic system with high accuracy in comparing measurement results.

[0005] In a first aspect, a photovoltaic module measuring device is provided, comprising:

[0006] The switching module has multiple first terminals that are connected one-to-one to multiple photovoltaic modules;

[0007] The measuring instrument has its input end connected to the second end of the switching module, and its output end is used to connect to the back-end circuit of the photovoltaic system.

[0008] The control system's input terminal is connected to the output terminal of the measuring instrument;

[0009] The switching module switches on each photovoltaic module and measuring instrument in a time-sharing manner.

[0010] In one embodiment, the switching module includes:

[0011] The high-frequency switching element has multiple first terminals that are connected one-to-one to multiple photovoltaic modules, and the second terminal of the high-frequency switching element is connected to the input terminal of the measuring instrument. Within one working cycle, the high-frequency switching element conducts each photovoltaic module and the measuring instrument in a time-sharing manner.

[0012] In one embodiment, the high-frequency switching element sequentially turns on each photovoltaic module and measuring instrument in a time-sharing manner during one working cycle.

[0013] In one embodiment, the output of the control system is connected to the high-frequency switching element. The control system outputs a drive signal to the high-frequency switching element, which drives the high-frequency switching element to switch between different photovoltaic modules and measuring instruments at a preset waiting time.

[0014] In one embodiment, the measuring instrument is an electricity meter used to measure the current and voltage of the photovoltaic module.

[0015] In one embodiment, the control system is used to output the power generation corresponding to the current and voltage of the photovoltaic module.

[0016] In one embodiment, the photovoltaic module measuring device further includes:

[0017] The housing has multiple input terminals for connecting each photovoltaic module and output terminals for connecting the back-end circuit of the photovoltaic system.

[0018] The switching module, measuring instruments, and control system are all housed within the cavity of the housing;

[0019] The multiple first terminals of the switching module are connected one-to-one with the multiple input terminals on the housing, and the output terminal of the measuring instrument is connected to the output terminal on the housing.

[0020] In one embodiment, the control system includes:

[0021] The power calculator's input terminal connects to the output terminal of the measuring instrument. The power calculator is used to output the power of the photovoltaic module.

[0022] The memory is connected to the output of the power calculator.

[0023] Secondly, a photovoltaic system is provided, including:

[0024] Multiple photovoltaic modules;

[0025] The aforementioned photovoltaic module measuring device;

[0026] Back-end circuitry of a photovoltaic system.

[0027] In one embodiment, the back-end circuit of the photovoltaic system includes:

[0028] A grid-connected inverter has its input terminal connected to the output terminal of a measuring instrument, and its output terminal is used to connect to the power grid.

[0029] The aforementioned photovoltaic module measuring device and photovoltaic system, by connecting a measuring instrument in series between the photovoltaic modules and the back-end circuits of the photovoltaic system, and cooperating with the time-sharing switching of the switching module, achieve online time-sharing measurement of each photovoltaic module. Furthermore, because the same measuring instrument is used, it avoids the comparison measurement errors caused by the malfunction of multiple meters or variations in measurement accuracy when measuring photovoltaic modules with multiple meters. Using the same measuring instrument also reduces costs. In other words, the low-cost photovoltaic module measuring device provided in this application embodiment can be used to measure important data such as the power generation of photovoltaic modules and ensures the accuracy of the comparison measurement results. Attached Figure Description

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 One of the structural schematic diagrams of a photovoltaic module measuring device and a photovoltaic system according to one or more embodiments;

[0032] Figure 2 A second schematic diagram of a photovoltaic module measuring device and a photovoltaic system according to one or more embodiments;

[0033] Figure 3 The third schematic diagram of a photovoltaic module measuring device and a photovoltaic system according to one or more embodiments;

[0034] Figure 4 Fourth schematic diagram of a photovoltaic module measuring device and a photovoltaic system according to one or more embodiments;

[0035] Figure 5 Fifth schematic diagram of a photovoltaic module measuring device and a photovoltaic system according to one or more embodiments;

[0036] Figure 6 This is a schematic diagram of the test results of a photovoltaic module measuring device in one embodiment.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Photovoltaic system; 10. Photovoltaic module measuring device; 11. Switching module; 111. High-frequency switching element; 12. Measuring instrument; 13. Control system; 131. Power calculator; 132. Memory; 20. Photovoltaic module; 30. Back-end circuit of photovoltaic system. Detailed Implementation

[0039] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0041] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0042] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0043] In one embodiment, Figure 1 As shown, a photovoltaic module measuring device 10 is provided, including: a switching module 11, a measuring instrument 12, and a control system 13.

[0044] In this system, the multiple first terminals of the switching module 11 are connected one-to-one with multiple photovoltaic modules 20. The input terminal of the measuring instrument 12 is connected to the second terminal of the switching module 11, and the output terminal of the measuring instrument 12 is used to connect to the back-end circuit 30 of the photovoltaic system. The input terminal of the control system 13 is connected to the output terminal of the measuring instrument 12. The switching module 11 turns on each photovoltaic module 20 and the measuring instrument 12 in a time-sharing manner.

[0045] The switching module 11 refers to a device or circuit that supports the selective activation of either the first terminal or the second terminal. For example, the switching module 11 may include, but is not limited to, a high-frequency switching element 111, such as a single-pole multi-throw switch, a multi-pole multi-throw switch chip, or a high-speed analog switch module.

[0046] Measuring instrument 12 refers to an instrument used to measure the electrical performance of photovoltaic module 20. For example, it could be an electricity meter. It measures the voltage and current of photovoltaic module 20.

[0047] The control system 13 refers to a device or circuit capable of at least receiving and storing signals output by the measuring instrument 12. The photovoltaic system back-end circuit 30 refers to the subsequent circuit used for storing, converting, and processing the DC power output by the photovoltaic module 20. For example, the photovoltaic system back-end circuit 30 may include an inverter, energy storage device, combiner, AC grid-connected system, etc.

[0048] Specifically, a measuring instrument 12 is connected in series between the photovoltaic module 20 and the photovoltaic system back-end circuit 30. Combined with the time-sharing switching of the switching module 11, online time-sharing measurement of each photovoltaic module 20 is achieved. Since the same measuring instrument 12 is used, measurement errors caused by multiple meters measuring the photovoltaic module 20 are avoided, and costs are reduced. That is, the low-cost photovoltaic module measuring device 10 provided in this application embodiment can be used to measure important data such as the power generation of the photovoltaic module 20 and ensure the accuracy of the comparative measurement results.

[0049] In one embodiment, Figure 2 As shown, the switching module 11 includes a high-frequency switching element 111.

[0050] Among them, the multiple first terminals of the high-frequency switching element 111 are connected to the multiple photovoltaic modules 20 one by one, and the second terminal of the high-frequency switching element 111 is connected to the input terminal of the measuring instrument 12. The high-frequency switching element 111 conducts each photovoltaic module 20 and the measuring instrument 12 in a time-division manner within one working cycle.

[0051] The high-frequency switching element 111 may include, but is not limited to, IGBTs (Insulated Gate Bipolar Transistors), solid-state relays, or MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). For example, the high-frequency switching element 111 may include multiple IGBTs, the number of which is consistent with the number of photovoltaic modules 20. The input terminals of the multiple IGBTs are connected one-to-one with the output terminals of each photovoltaic module 20. Each IGBT is turned on in a time-sharing manner within one working cycle, enabling time-sharing measurement of each photovoltaic module 20 by the measuring instrument 12 in one working cycle.

[0052] By employing a high-frequency switching element 111, the photovoltaic modules 20 and the measuring instrument 12 are connected via high-frequency switching. When the measurement accuracy of the measuring instrument 12 fluctuates, the difference in the impact of the measurement accuracy fluctuation of the measuring instrument 12 on the measurement results of multiple different photovoltaic modules 20 can be reduced, thereby ensuring high reliability of the results when comparing the power generation performance of multiple photovoltaic modules 20.

[0053] In one embodiment, the high-frequency switching element 111 sequentially and time-divisionally turns on each of the photovoltaic modules 20 and the measuring instrument 12 within one working cycle. For example, the high-frequency switching element 111 can be a cyclic switching switch. By cyclically switching the second terminal to each of the first terminals within one working cycle, each photovoltaic module 20 and the measuring instrument 12 can be sequentially turned on, realizing time-division measurement of each photovoltaic module 20, and ensuring that each photovoltaic module 20 is measured within one working cycle, with consistent measurement duration. This facilitates the comparison of measurement results of multiple photovoltaic modules 20 under the same conditions, improving the reliability of the evaluation results of the performance of multiple photovoltaic modules 20 based on comparison. By selecting different models of cyclic switching switches, different working cycles of the switching module 11 can be set.

[0054] In one embodiment, Figure 2 As shown, there can be two photovoltaic modules 20. The power generation performance of the photovoltaic modules 20 is evaluated by measuring and comparing the power generation of the two photovoltaic modules 20. In this scenario, a switching module 11 with a working cycle of 5 seconds can be selected.

[0055] In one embodiment, the output of the control system 13 is connected to the high-frequency switching element 111. The control system 13 outputs a drive signal to the high-frequency switching element 111. The drive signal drives the high-frequency switching element 111 to switch different photovoltaic modules 20 and measuring instruments 12 within a working cycle with a preset waiting time.

[0056] The control system 13 controls the conduction between each photovoltaic module 20 and the measuring instrument 12 at a preset waiting time interval, which can provide time for the measuring instrument 12 to measure and transmit data.

[0057] In one embodiment, the control system 13 drives the high-frequency switching element 111 to switch the conduction of each photovoltaic module 20 and the measuring instrument 12 at a waiting time interval greater than 0 milliseconds and less than or equal to 20 milliseconds.

[0058] If the waiting time is too long, the measurement results may differ due to the accuracy fluctuation of the measuring instrument 12 when switching to different photovoltaic modules 20. When the waiting time is less than or equal to 20 milliseconds, the difference in measurement results between different photovoltaic modules 20 is minimal due to the fault or accuracy fluctuation of the measuring instrument 12 itself. Therefore, the photovoltaic module 20 testing device provided in this application embodiment controls the switching module 11 to switch from one photovoltaic module 20 to the next photovoltaic module 20 with a waiting time interval greater than 0 milliseconds and less than or equal to 20 milliseconds. This ensures that the measuring instrument 12 has time to collect and transmit data, and also ensures the reliability of the comparison results when comparing the measurement results between multiple groups of photovoltaic modules 20.

[0059] In one embodiment, the driving signal is a square wave signal. The driving signal can also be a pulse signal.

[0060] For example, such as Figure 3 As shown, the high-frequency switching element 111 may include multiple switching transistors (e.g., switching transistors S1 and S2 in the figure). The control system 13 includes a microcontroller, which may be an STM32 series microcontroller. Multiple output pins of the microcontroller are connected to the controlled terminals of the multiple switching transistors, and the input terminals of the multiple switching transistors are all connected to a logic power supply (e.g., a 3.3V voltage source). The input terminals of the multiple switching transistors are connected to each photovoltaic module 20. The multiple pins of the microcontroller output high-level pulse signals in turn in turn to trigger the multiple switching transistors to conduct sequentially in a time-sharing manner, thereby realizing the time-sharing conduction of each photovoltaic module 20 and the measuring instrument 12.

[0061] Optionally, the control system 13 can be a microcontroller, and one output pin of the microcontroller can be connected to, for example... Figure 4 The two switching transistors shown alternately output high and low levels when the microcontroller is powered on. When Q1 outputs a high level, it conducts, connecting the photovoltaic module 20 and the measuring instrument 12, which then performs measurements on the photovoltaic module 20. When the microcontroller outputs a low level, Q1 is turned off, and Q2 conducts, connecting the photovoltaic module 20 and the measuring instrument 12, which then performs measurements on the photovoltaic module 20.

[0062] In one embodiment, the measuring instrument 12 is an electricity meter used to measure the current and voltage of the photovoltaic module 20. Current, voltage, and power are instantaneous values, while power generation is a cumulative value over time. The electricity meter can collect the current and voltage of the photovoltaic module 20 multiple times within a certain period and send them to the control system 13. Based on the control system 13 or a remote terminal, the power generation of the photovoltaic module 20 is calculated. Besides measuring the current and voltage of the photovoltaic module 20, different types of electricity meters can also be selected to measure other parameters of the photovoltaic module 20, such as the amount of electricity generated.

[0063] The current and voltage of the photovoltaic module 20 reflect the power generation of the photovoltaic module 20. Therefore, the power generation of the photovoltaic module 20 can be obtained through the electricity meter, thereby realizing the comparison of the power generation between multiple photovoltaic modules 20 and the comparative test of the power generation performance of the photovoltaic module 20. The comparison test results are highly accurate.

[0064] In one embodiment, the measuring instrument 12 is a high-precision electricity meter. Since a single measuring instrument 12 is used, a high-precision electricity meter can be selected to measure the current and voltage of the photovoltaic module 20 while effectively controlling costs, thereby improving the accuracy of the measurement results of the photovoltaic module 20 and improving the accuracy of the comparison results of the power generation of the photovoltaic module 20.

[0065] In one embodiment, Figure 5 As shown, the control system 13 includes a power calculator 131 and a memory 132.

[0066] The power calculator 131 has its input terminal connected to the output terminal of the measuring instrument 12, and is used to output the power of the photovoltaic module 20. The memory 132 is connected to the output terminal of the power calculator 131.

[0067] The power calculator 131 can calculate the power of the photovoltaic module 20 based on the received current and voltage, and store it in the memory 132 for retrieval and viewing.

[0068] For example, the power stored in the memory 132 and the measurement time of each photovoltaic module 20 by the measuring instrument 12 can be integrated to obtain the power generation of each photovoltaic module 20. Then, the power generation of multiple photovoltaic modules 20 can be compared. It should be noted that when the photovoltaic module measuring device 10 provided in this application compares the performance of multiple photovoltaic modules 20, the installation environment such as the installation position and installation angle of the photovoltaic modules 20 should be kept the same to avoid differences in measurement performance results caused by differences in the installation environment.

[0069] To better illustrate the implementation process of the photovoltaic module measuring device 10 provided in this application embodiment, the following example is provided:

[0070] The control system 13 controls the high-frequency switching element 111 to switch between two photovoltaic modules 20. When switching to a certain photovoltaic module 20, the meter measures the current and voltage at that time. The control system 13 reads the meter reading and stores the reading in the control system 13. Based on the meter reading and the switching time, the control system 13 can calculate the power generation of each photovoltaic module 20. The power calculation can be performed using the control system 13 equipped with an online power calculator 131. The power generation can be calculated using an online integrator based on the power generation and the time of data acquisition by the measuring instrument 12. Of course, the control system 13 can also send the stored current and voltage to remote terminals such as mobile phones, tablets, and laptops for calculation. In this case, the control system 13 includes a communication module connected to the memory 132 to send the current and voltage stored in the memory 132 to the remote terminal.

[0071] In one embodiment of this application, the control system 13 performs the measurement work of the photovoltaic module 20 cyclically at a fixed period T. When the set acquisition period T is reached, as... Figure 2 As shown, the control system 13 controls the high-frequency switching element 111 to connect the photovoltaic module A to the electricity meter, and the electricity meter measures the current I of the photovoltaic module A at this time. A Voltage value UA The control system 13 simultaneously reads I A and U A And the power value P was calculated. A Control system 13 stores P A value.

[0072] To ensure the control system 13 reliably completes data reading, calculation, storage, and meter switching, and the system reaches a stable operating state, after a waiting time t (t much shorter than the acquisition period T) between switching photovoltaic module A and photovoltaic module B, the control system 13, after completing data reading and storage for photovoltaic module A, controls the high-frequency switching element 111 to connect photovoltaic module B to the meter. The meter then measures the current I of photovoltaic module A at this time. B Voltage value U B The control system 13 simultaneously reads I B and U B The power value P was calculated. B Control system 13 stores P B Value; such as Figure 6 As shown.

[0073] The control system 13 will measure P within the empirical duration (the conduction time of each photovoltaic module 20 and the meter). A and P B The power generation Q of photovoltaic module A is calculated by time integration based on the following expressions. A The power generation Q of photovoltaic module B B :

[0074]

[0075] Where Period represents the empirical duration.

[0076] As long as the solar intensity remains unchanged within the "waiting time t" (or in other words, the waiting time t is small enough), then the time-division measured P A and P B This can accurately reflect the power generation of photovoltaic module A and photovoltaic module B under the same conditions. For example, a waiting time greater than 0 milliseconds and less than or equal to 20 milliseconds can be set, and the acquisition period T can be set to 5 seconds.

[0077] The photovoltaic module measuring device 10 provided in this application embodiment achieves the function of measuring the power generation of multiple photovoltaic modules 20 with one meter based on the principle of short-term time-sharing occupancy. It has low cost and the power generation comparison results have high reliability.

[0078] In one embodiment, Figure 5As shown, a photovoltaic system 1 is provided, including: a plurality of photovoltaic modules 20, the photovoltaic module measuring device 10, and a photovoltaic system back-end circuit 30.

[0079] The photovoltaic system 1 equipped with the photovoltaic module measurement device 10 can support online measurement and comparison of multiple photovoltaic modules 20, and the comparison results are highly reliable.

[0080] In one embodiment, the photovoltaic system back-end circuit 30 includes a grid-connected inverter.

[0081] The input terminal of the grid-connected inverter is connected to the output terminal of the measuring instrument 12, and the output terminal of the grid-connected inverter is used to connect to the power grid.

[0082] A grid-connected inverter can convert direct current (DC) into alternating current (AC). Its output AC can be synchronized with the frequency and phase of the mains power, so the output AC can be returned to the mains power.

[0083] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A photovoltaic module measuring device, characterized in that, include: A switching module (11) is provided, wherein multiple first terminals of the switching module (11) are connected one-to-one to multiple photovoltaic modules (20). Measuring instrument (12), the input end of which is connected to the second end of the switching module (11), and the output end of which is used to connect to the back-end circuit (30) of the photovoltaic system. A control system (13) is connected to the output of the measuring instrument (12). The switching module (11) switches on each of the photovoltaic modules (20) and the measuring instrument (12) in a time-sharing manner.

2. The photovoltaic module measuring device according to claim 1, characterized in that, The switching module (11) includes: A high-frequency switching element (111) is provided, with multiple first terminals of the high-frequency switching element (111) connected one-to-one to multiple photovoltaic modules (20), and a second terminal of the high-frequency switching element (111) connected to the input terminal of the measuring instrument (12). The high-frequency switching element (111) is used to conduct each photovoltaic module (20) and the measuring instrument (12) in a time-division manner within one working cycle.

3. The photovoltaic module measuring device according to claim 2, characterized in that, The high-frequency switching element (111) sequentially turns on each of the photovoltaic modules (20) and the measuring instrument (12) in a time-sharing manner within one working cycle.

4. The photovoltaic module measuring device according to claim 2, characterized in that, The output of the control system (13) is connected to the high-frequency switching element (111). The control system (13) outputs a drive signal to the high-frequency switching element (111). The drive signal drives the high-frequency switching element (111) to switch different photovoltaic modules (20) and the measuring instrument (12) at the preset waiting time.

5. The photovoltaic module measuring device according to claim 1, characterized in that, The measuring instrument (12) is an electricity meter, which is used to measure the current and voltage of the photovoltaic module (20).

6. The photovoltaic module measuring device according to claim 1, characterized in that, The control system (13) is used to output the power generation corresponding to the current and voltage of the photovoltaic module (20).

7. The photovoltaic module measuring device according to claim 1, characterized in that, Also includes: The housing is provided with multiple input terminals for connecting each photovoltaic module (20) in a one-to-one correspondence and output terminals for connecting the back-end circuit of the photovoltaic system; The switching module (11), the measuring instrument (12), and the control system (13) are all located inside the cavity of the housing; The multiple first terminals of the switching module (11) are connected one-to-one with the multiple input terminals on the housing, and the output terminal of the measuring instrument (12) is connected to the output terminal on the housing.

8. The photovoltaic module measuring device according to any one of claims 1-7, characterized in that, The control system (13) includes: A power calculator (131) is provided, the input of which is connected to the output of the measuring instrument (12), and the power calculator (131) is used to output the power of the photovoltaic module (20). The memory (132) is connected to the output of the power calculator (131).

9. A photovoltaic system, characterized in that, include: Multiple photovoltaic modules (20); Photovoltaic module measuring device (10) as described in any one of claims 1-8; Photovoltaic system back-end circuit (30).

10. The photovoltaic system according to claim 9, characterized in that, The photovoltaic system back-end circuit (30) includes: A grid-connected inverter, the input terminal of which is connected to the output terminal of the measuring instrument (12), and the output terminal of which is used to connect to the power grid.

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