Junction temperature testing device of photovoltaic junction box

Abstract

The utility model relates to a junction temperature testing device of a photovoltaic junction box, which belongs to the field of junction temperature testing of semiconductor power devices and comprises a testing board, two groups of bus bars are pre-buried on the testing board, and the bus bars are electrically connected with two ends of a diode in the photovoltaic junction box respectively. Two groups of leads are arranged on a diode in the photovoltaic junction box, and the two groups of leads and the two groups of bus bars form Kelvin wiring method connection; the high-temperature accommodating box is used for providing an environment temperature required by the test of the test board; the direct-current voltage source meter is electrically connected with the photovoltaic junction box; the temperature acquisition unit is used for detecting the temperature of the photovoltaic junction box; and the control module is electrically connected with the high-temperature accommodating box and the direct-current voltage source meter. The junction temperature testing device of the photovoltaic junction box is simple and convenient to operate and less in manual intervention, greatly reduces testing errors and testing interference, and further can quickly and accurately measure the junction temperature of the photovoltaic junction box.

Description

Technical Field

[0001] The utility model relates to the field of junction temperature testing of semiconductor power devices, in particular to a junction temperature testing device for a photovoltaic junction box. Background Art

[0002] Photovoltaic junction boxes are important components in solar photovoltaic power generation systems. They are used to centrally connect and protect the cables between solar panels, and they also play a role in bypass protection in photovoltaic modules. The internal structure of photovoltaic junction boxes on the market is generally assembled by welding wires and discrete diode devices, and potting glue is used in the junction box. When the solar cell has a hot spot and cannot generate electricity, the diode will conduct forward and play a bypass role. However, the diode will continue to release heat when it is turned on for a long time. If the junction temperature of the junction box is not properly evaluated, it is easy to cause the junction box to fail as a whole due to excessive heat generation, or even cause a fire.

[0003] At present, the junction temperature test of photovoltaic junction boxes is usually measured by a combination of multiple devices, where multiple devices usually belong to different equipment manufacturers, the data cannot be interoperable, and various data need to be manually processed, selected and the junction temperature is settled. The steps are cumbersome and there are many manual intervention processes. Therefore, it is urgent to design a highly automated junction temperature test device for photovoltaic junction boxes. Utility Model Content

[0004] In view of the above-mentioned technical problems, the purpose of the utility model is to provide a junction temperature testing device for a photovoltaic junction box, which refers to IEC-62790 in accordance with relevant regulations, can automatically perform junction temperature testing and calculate junction temperature data through program settings, can improve the test steps of the junction temperature testing process, and reduce manual intervention, so that the junction temperature test is automated and programmed, and the results are clear and consistent.

[0005] To solve the above technical problems, the utility model provides a junction temperature testing device for a photovoltaic junction box, comprising a test board, wherein the test board is used to place the photovoltaic junction box and simulate the solar cell in the actual use of the photovoltaic junction box; two groups of busbars are pre-buried on the test board, and the busbars are electrically connected to the two ends of the diode in the photovoltaic junction box respectively; two groups of leads are arranged on the diode in the photovoltaic junction box, and the two groups of leads and the two groups of busbars form a Kelvin wiring method connection; a high-temperature containing box, which is used to hold the test board and provide the environmental temperature required for the test board test; a DC voltage source meter, which is electrically connected to the photovoltaic junction box; a temperature acquisition unit, which is used to detect the temperature of the photovoltaic junction box; and a control module, which is electrically connected to the high-temperature containing box and the DC voltage source meter respectively.

[0006] Preferably, the busbar is fixed on the test board by means of a sealant.

[0007] Preferably, the bus bar is welded and electrically connected to the diode electrode in the photovoltaic junction box.

[0008] Preferably, the temperature acquisition unit includes a temperature probe, the temperature probe is fixed on the diode housing in the photovoltaic junction box, and the temperature probe is used to detect the temperature of the diode.

[0009] Preferably, there are three groups of temperature probes, which are respectively arranged on the diode housing in the photovoltaic junction box and the positive and negative poles of the diode. The three groups of temperature probes are respectively used to detect the temperature of the diode and the positive and negative poles of the diode.

[0010] Preferably, the DC voltage source meter outputs a plurality of pulse signals at a certain interval time, and the interval time of the plurality of pulse signals ≥ 0.5 ms.

[0011] Preferably, the DC voltage source meter outputs a stable DC signal.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The present invention provides a junction temperature testing device for a photovoltaic junction box. In the technical solution of the junction temperature testing device for a photovoltaic junction box provided by the present invention, the photovoltaic junction box is first placed on the photovoltaic junction box test board, and the embedded bus bar is connected to the positive and negative poles of the diode in the photovoltaic junction box. Two connection leads are simultaneously led out from the diode and are electrically connected to the DC voltage source meter together with the embedded bus bar. The temperature sensing probe is placed in the photovoltaic junction box and connected to the temperature acquisition unit, and then the photovoltaic junction box test board is placed in the high-temperature accommodation box. The high-temperature accommodation box adjusts the temperature according to the control module. The junction temperature testing device for the photovoltaic junction box is simple and convenient to operate, with less manual intervention, and converts the adjustment, sampling, and calculation work into automation, greatly reducing the test error and test interference, and thus can quickly and accurately measure the junction temperature of the photovoltaic junction box. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the layout schematic diagram of the photovoltaic junction box test board of the present invention;

[0015] Figure 2 It is the principle block diagram of the junction temperature testing device for the photovoltaic junction box of the present invention;

[0016] Figure 3 It is the layout schematic diagram of the photovoltaic junction box test board of another embodiment of the present invention;

[0017] Figure 4 It is the fitting curve diagram of the photovoltaic junction box temperature and the forward voltage drop of the present invention.

[0018] In the figure, 1. test board, 2. photovoltaic junction box, 3. lead wire, 4. busbar, 5. high temperature containment box, 6. DC voltage source meter, 7. temperature acquisition unit, 8. control module, 9. temperature probe. DETAILED DESCRIPTION

[0019] In order to further understand the purpose, structure, features and advantages of the present invention, the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "parallel", "symmetrical", "vertical line" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the structure referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] Embodiment 1

[0022] See also Figure 1 and Figure 2 As shown, an embodiment of the utility model provides a junction temperature testing device for a photovoltaic junction box, comprising a test board 1, wherein the test board 1 is used to place a photovoltaic junction box 2, simulating the solar cell in the actual use of the photovoltaic junction box 2; two groups of busbars 4 are pre-buried on the test board 1, and the busbars 4 are respectively electrically connected to the two ends of the diode in the photovoltaic junction box 2; two groups of leads 3 are arranged on the diode in the photovoltaic junction box 2, and the two groups of leads 3 and the two groups of busbars 4 form a Kelvin wiring method connection; a high-temperature containing box 5, wherein the high-temperature containing box 5 is used to hold the test board 1 of the photovoltaic junction box to be tested, and has a sealing heating function to control the internal temperature of the high-temperature containing box 5 to reach the required temperature for the test, and provide the required ambient temperature for the test of the test board 1.

[0023] A DC voltage source meter 6 is used to be electrically connected to the photovoltaic junction box 2; a temperature acquisition unit 7 is used to detect the temperature of the photovoltaic junction box 2; the DC voltage source meter 6 is electrically connected to the diode in the photovoltaic junction box 2, and the DC voltage source meter 6 has two working modes, namely the first mode and the second mode. The DC voltage source meter 6 is used in the first mode to provide a pulse current signal to the photovoltaic junction box 2 and detect the forward voltage drop during the high level period of the pulse current signal; the DC voltage source meter 6 is used in the second mode to provide a stable DC signal to the photovoltaic junction box 2 and continuously detect the forward voltage drop under the DC signal. Specifically, the DC voltage source meter 6 can output a regulated current and can control the magnitude of the output current.

[0024] The busbar 4 is fixed on the test board 1 by means of sealant.

[0025] The bus bar 4 is welded and electrically connected to the diode electrode in the photovoltaic junction box 2.

[0026] The temperature acquisition unit 7 includes a temperature probe 9 which is fixed on the diode housing in the photovoltaic junction box 2, and the temperature probe 9 is used to detect the temperature of the diode.

[0027] Such as Figure 1 and Figure 4As shown, there is a control module 8, and the control module 8 is electrically connected to the high-temperature containment box 5 and the DC voltage source meter 6 respectively, and is respectively used to control the temperature adjustment of the high-temperature containment box 5 and the DC signal output adjustment of the DC voltage source meter 6. The control module 8 includes an adjustment mode, a reading mode, and a calculation output mode. The adjustment mode can adjust the temperature and stabilization time of the high-temperature containment box 5 according to the setting, and adjust the operation mode and output current of the DC voltage source meter 6, so that the DC voltage source meter 6 operates in the corresponding mode at the corresponding temperature; the reading mode can read and record the forward voltage drop detected by the DC voltage source meter 6 and the temperature detected by the temperature acquisition unit 7 at the same time; the calculation output mode can calculate the average value of the forward voltage drop in the high-level period of the current signal detected by the DC voltage source meter 6 in the first mode, and fit it with the temperature detected by the temperature acquisition unit 7 at the same time to obtain a fitting curve Tj = Kvf + b of the forward voltage drop and the junction temperature, and substitute the stable forward voltage drop detected by the DC voltage source meter 6 in the second mode into the fitting curve to calculate and output the junction temperature. The DC voltage source meter 6 outputs a plurality of pulse signals at a certain interval time, and the interval time of the plurality of pulse signals ≥ 0.5 ms. The DC voltage source meter 6 outputs a stable DC signal. In the embodiment of the present invention, the photovoltaic junction box test board 1 with the photovoltaic junction box 2 placed and connected is placed in the high-temperature containment box 5. The diode in the photovoltaic junction box 2 is connected to the DC voltage source meter 6 by the Kelvin connection method through the bus bar 4 and the connection lead 3, and the temperature sensor probe 9 is connected to the temperature acquisition unit 7 to monitor the temperature of the photovoltaic junction box 2. The high-temperature containment box 5 is heated to the first temperature point, for example, 30 °C, by the control module 8. After stabilizing to the thermal equilibrium of the photovoltaic junction box 2, the DC voltage source meter 6 is triggered to operate in the first mode, providing a pulsed current signal to the photovoltaic junction box 2, and detecting the forward voltage drop in the high-level period of the pulsed current signal. The control module 8 operates in the reading mode, records the forward voltage drop in the high-level period and the temperature detected by the temperature acquisition unit 7, and records them as VF1 and T1. The high-temperature containment box 5 is heated to the second temperature point, for example, 50 °C, by the control module 8. After stabilizing to the thermal equilibrium of the photovoltaic junction box 2, the DC voltage source meter 6 is triggered to operate in the first mode, providing a pulsed current signal to the photovoltaic junction box 2, and detecting the forward voltage drop in the high-level period of the pulsed current signal. The control module 8 operates in the reading mode, records the forward voltage drop in the high-level period and the temperature detected by the temperature acquisition unit 7, and records them as VF2 and T2.The control module 8 raises the temperature of the high-temperature containment box 5 to a third temperature point, such as 70 °C. After stabilizing to the thermal equilibrium of the photovoltaic junction box 2, the DC voltage source meter 6 is triggered to operate in the first mode, providing a pulsed current signal to the photovoltaic junction box 2, and detecting the forward voltage drop during the high-level period of the pulsed current signal. The control module 8 operates in the reading mode, records the forward voltage drop during the high-level period and the temperature detected by the temperature acquisition unit 7, and records them as VF3 and T3. By operating the calculation and output mode of the control module 8, VF1, T1, VF2, T2, VF3, and T3 are fitted to output the characteristic curve Tj = Kvf + b of the forward voltage drop VF of the diode and the junction temperature Tj. The control module 8 adjusts the high-temperature containment box 5 to 75 °C, and triggers the DC voltage source meter 6 to operate in the second mode, providing a stable DC signal to the photovoltaic junction box 2, and continuously detecting the forward voltage drop under the DC signal. After waiting for the photovoltaic junction box 2 to stabilize to thermal equilibrium, the control module 8 operates in the reading mode, records the stable forward voltage drop and records it as VFw. The control module 8 operates in the calculation and output mode, substitutes VFw into Tj = Kvf + b to obtain the junction temperature of the photovoltaic junction box 2.

[0028] Optionally, the control module 8 can control the high-temperature containment box 5 to operate at greater than or equal to three temperature points, record greater than or equal to three VFs and Ts, and perform curve fitting.

[0029] Based on this, a photovoltaic junction box junction temperature testing device provided by an embodiment of the present invention thermally stabilizes the photovoltaic junction box 2 within at least three temperature points through the adjustment mode of the control module 8, triggers the DC voltage source meter 6 to provide a pulsed current in the first mode and detect the forward voltage drop during the high-level period, and records the temperature and forward voltage drop at each temperature point, thereby outputting the fitting curve Tj = Kvf + b of the forward voltage drop and the junction temperature. The control module 8 stabilizes the temperature of the high-temperature containment box 5 at 75 °C, the DC voltage source meter 6 operates in the second mode, provides a stable DC signal to the photovoltaic junction box 2, reads the stable forward voltage drop and substitutes it into the fitting curve to calculate and output the junction temperature. Compared with the existing testing methods, the junction temperature testing device of the photovoltaic junction box is simple and convenient to operate, has less manual intervention, converts the adjustment, sampling, and calculation work into automation, greatly reduces the testing error and testing interference, and can thus quickly and accurately measure the junction temperature of the photovoltaic junction box.

[0030] The sizes of the photovoltaic junction box, the sizes of the busbars, and the structure of the control module not elaborated in detail in the present invention are all prior arts and will not be described in detail.

[0031] Embodiment 2

[0032] See Figure 3As shown in the figure, the present utility model provides another embodiment of a junction temperature testing device for a photovoltaic junction box. The difference between the embodiment of the present utility model and the first embodiment is that the temperature acquisition unit 7 includes temperature probes 9, and there are three groups of the temperature probes 9, which are respectively arranged on the diode housing in the photovoltaic junction box 2 and at the positive and negative electrodes of the diode. The three groups of temperature probes 9 are respectively used to detect the temperature of the diode and the positive and negative electrodes of the diode.

[0033] The power module size, bushing size, and installation method not described in detail in the present utility model are all prior arts and will not be elaborated here.

[0034] The principle and implementation manner of the present utility model have been described through specific embodiments. The description of the above embodiments is only used to help understand the method and core idea of the present utility model. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A junction temperature test device for a photovoltaic junction box, characterized in that: The test board (1) comprises a test board (1), wherein the test board (1) is used to place a photovoltaic junction box (2) and simulate the solar cell in the actual use of the photovoltaic junction box (2); two groups of busbars (4) are pre-buried on the test board (1), and the busbars (4) are respectively electrically connected to the two ends of the diode in the photovoltaic junction box (2); two groups of lead wires (3) are arranged on the diode in the photovoltaic junction box (2), and the two groups of lead wires (3) and the two groups of busbars (4) form a Kelvin wiring method connection; A high temperature containing box (5), used for containing the test board (1) and providing an environmental temperature required for testing the test board (1); A DC voltage source meter (6), used for being electrically connected to the photovoltaic junction box (2); A temperature collection unit (7), used for detecting the temperature of the photovoltaic junction box (2); A control module (8), wherein the control module (8) is electrically connected to the high-temperature containment box (5) and the DC voltage source meter (6) respectively.

2. The junction temperature testing device for a photovoltaic junction box according to claim 1, characterized in that: The busbar (4) is fixed on the test board (1) by means of a sealant.

3. The junction temperature testing device for a photovoltaic junction box according to claim 1, characterized in that: The busbar (4) is electrically connected to the diode electrodes in the photovoltaic junction box (2) by welding.

4. The junction temperature testing device for a photovoltaic junction box according to claim 1, characterized in that: The temperature acquisition unit (7) comprises a temperature probe (9), the temperature probe (9) is fixed on a diode housing in a photovoltaic junction box (2), and the temperature probe (9) is used to detect the temperature of the diode.

5. The junction temperature testing device for a photovoltaic junction box according to claim 4, characterized in that: The temperature probes (9) are in three groups, which are respectively arranged on the diode housing in the photovoltaic junction box (2) and on the positive and negative ends of the diode. The three groups of temperature probes (9) are used to detect the temperature of the diode and the positive and negative ends of the diode respectively.

6. The junction temperature testing device for a photovoltaic junction box according to claim 1, characterized in that: The DC voltage source meter (6) outputs a plurality of pulse signals at a certain interval, and the interval between the plurality of pulse signals is ≥0.5 ms.

7. A junction temperature testing device for a photovoltaic junction box according to claim 1, characterized in that: The DC voltage source meter (6) outputs a stable DC signal.

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