Testing method and testing device for bypass diode

Abstract

The invention discloses a bypass diode test method and a bypass diode test device, and belongs to the field of photovoltaic technology. The method comprises the following steps: acquiring forward voltage drop values of a bypass diode to be measured at different temperatures in a target temperature range, and determining a voltage drop and junction temperature relationship between the forward voltage drop and the junction temperature of the bypass diode; obtaining reverse withstand voltage extreme values of the bypass diode at different temperatures in the target temperature range, and determining a junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode; and determining a test result of the bypass diode according to at least one of the voltage drop junction temperature relation and the junction temperature withstand voltage relation based on the component performance parameters of the bypass diode. The method can quickly and accurately judge the safety and reliability of the bypass diode when the assembly works for a long time.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic technology, and in particular relates to a bypass diode testing method and testing device. Background Art

[0002] When a cell or a group of cells in a photovoltaic module is shaded or damaged, the module may experience a hot spot effect, which is an important factor affecting the quality and safety of photovoltaic modules. Bypass diodes are important components that reduce the risk of fire caused by hot spot effects. Therefore, the long-term reliability and safety of bypass diodes are crucial.

[0003] When a hot spot occurs in a component, the diode will continue to generate heat during forward startup and will be at high temperature for a long time. If the hot spot disappears at this time, the diode will switch from forward operation to reverse operation instantly. The reverse voltage withstand performance of the diode will decrease under high temperature, and thermal runaway breakdown is likely to occur. The current diode thermal runaway test method is: after the rated current is passed forward for a certain period of time at a certain temperature (the diode works forward when simulating a hot spot), it is switched to the reverse bias state. If the reverse leakage current and the diode temperature are both in a decreasing state, the test passes. This type of test method is difficult to accurately judge the safety and reliability of the diode during the long-term operation of the component. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a bypass diode testing method and testing device, which can quickly and accurately determine the safety and reliability of the bypass diode during the long-term operation of the component.

[0005] In a first aspect, the present application provides a bypass diode testing method, comprising:

[0006] Obtaining forward voltage drop values ​​of the bypass diode to be tested at different temperatures within a target temperature range, and determining a voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode;

[0007] Obtaining the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range, and determining the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode;

[0008] Based on the component performance parameters of the bypass diode, a test result of the bypass diode is determined according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

[0009] According to the bypass diode testing method of the present application, through the voltage drop junction temperature relationship and junction temperature withstand voltage relationship of the bypass diode, combined with the component performance parameters corresponding to the bypass diode when it is actually connected in parallel with the component, it is judged whether the bypass diode can meet the requirements corresponding to the component performance parameters. The testing process is simple and can quickly and accurately judge the safety and reliability of the bypass diode when the component is working for a long time.

[0010] According to an embodiment of the present application, the component performance parameter includes a component opening voltage parameter of the bypass diode, and determining the test result of the bypass diode according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship includes:

[0011] Determining a first operating temperature of the bypass diode based on the component opening voltage parameter and the junction temperature withstand voltage relationship;

[0012] The first operating temperature is compared with an operating temperature threshold of the bypass diode, and a test result of the bypass diode is determined according to the comparison result.

[0013] According to an embodiment of the present application, comparing the first operating temperature with an operating temperature threshold of the bypass diode, and determining a test result of the bypass diode according to the comparison result, includes:

[0014] When the first operating temperature is greater than the operating temperature threshold, it is determined that the bypass diode test has passed.

[0015] According to an embodiment of the present application, the component performance parameter includes a component opening voltage parameter of the bypass diode and a diode voltage drop extreme value corresponding to the bypass diode at a diode junction temperature threshold, and the test result of the bypass diode is determined according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, including:

[0016] Determining a first operating temperature of the bypass diode based on the component opening voltage parameter and the junction temperature withstand voltage relationship;

[0017] Determining a second operating temperature of the bypass diode based on the diode voltage drop extreme value and the voltage drop junction temperature relationship;

[0018] The first operating temperature and the second operating temperature are compared, and a test result of the bypass diode is determined according to the comparison result.

[0019] According to an embodiment of the present application, comparing the first operating temperature with the second operating temperature and determining the test result of the bypass diode according to the comparison result includes:

[0020] When the first operating temperature is greater than or equal to the second operating temperature, it is determined that the bypass diode test has passed.

[0021] According to an embodiment of the present application, the component performance parameter includes a component opening voltage parameter of the bypass diode and a diode voltage drop extreme value corresponding to the bypass diode at a diode junction temperature threshold, and the test result of the bypass diode is determined according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, including:

[0022] Determining a voltage drop and withstand voltage relationship of the bypass diode based on the voltage drop and junction temperature relationship and the junction temperature and withstand voltage relationship;

[0023] Determining a first target withstand voltage of the bypass diode based on the diode voltage drop extreme value and the voltage drop withstand voltage relationship;

[0024] The first target withstand voltage is compared with the component start-up voltage parameter, and a test result of the bypass diode is determined according to the comparison result.

[0025] According to an embodiment of the present application, comparing the first target withstand voltage with the component start-up voltage parameter, and determining the test result of the bypass diode according to the comparison result, includes:

[0026] When the first target withstand voltage is greater than or equal to the component opening voltage parameter, it is determined that the bypass diode test has passed.

[0027] According to an embodiment of the present application, obtaining the forward voltage drop value of the bypass diode to be tested at different temperatures within the target temperature range includes:

[0028] When the temperature of the bypass diode reaches the target temperature value within the target temperature range, a first pulse current is applied to the bypass diode to obtain a forward voltage drop value corresponding to the target temperature value, and the magnitude of the first pulse current is the component short-circuit current value corresponding to the bypass diode.

[0029] According to an embodiment of the present application, obtaining the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range includes:

[0030] When the temperature of the bypass diode reaches the target temperature value within the target temperature range, a reverse voltage is applied to the bypass diode, the current output current of the bypass diode is obtained and the reverse voltage is gradually increased, it is determined that the current output current is greater than or equal to the first current threshold, and the reverse withstand voltage extreme value corresponding to the target temperature value is obtained.

[0031] According to an embodiment of the present application, the target temperature range is 20° C.-200° C., and the diode junction temperature threshold of the bypass diode is within the target temperature range.

[0032] In a second aspect, the present application provides a bypass diode testing device, comprising:

[0033] A first processing module is used to obtain the forward voltage drop value of the bypass diode to be tested at different temperatures within the target temperature range, and determine the voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode;

[0034] A second processing module is used to obtain the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range, and determine the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode;

[0035] The third processing module is used to determine the test result of the bypass diode based on the component performance parameters of the bypass diode and according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

[0036] According to the bypass diode testing device of the present application, through the voltage drop junction temperature relationship and junction temperature withstand voltage relationship of the bypass diode, combined with the component performance parameters corresponding to the bypass diode when the bypass diode is actually connected in parallel with the component, it is judged whether the bypass diode can meet the requirements corresponding to the component performance parameters. The testing process is simple and the safety and reliability of the bypass diode when the component is working for a long time can be judged quickly and accurately.

[0037] In a third aspect, the present application provides a bypass diode testing system, comprising:

[0038] An environmental chamber, the environmental chamber is used to place the bypass diode to be tested and provide a temperature environment within a target temperature range for the bypass diode;

[0039] A data acquisition device and a power supply device, wherein the data acquisition device and the power supply device are connected to the bypass diode, and the data acquisition device is used to collect current and voltage data of the bypass diode under the power supply of the power supply device;

[0040] As in the bypass diode testing device described in the second aspect above, the testing device is connected to the data acquisition device.

[0041] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0043] Figure 1 This is one of the flow charts of the bypass diode testing method provided in the embodiment of the present application;

[0044] Figure 2 This is a second flow chart of a bypass diode testing method provided in an embodiment of the present application;

[0045] Figure 3 This is the third flow chart of the bypass diode testing method provided in the embodiment of the present application;

[0046] Figure 4 This is a fourth flow chart of the bypass diode testing method provided in an embodiment of the present application;

[0047] Figure 5 is a structural schematic diagram of a bypass diode testing device provided in an embodiment of the present application;

[0048] Figure 6 It is a structural schematic diagram of a bypass diode testing system provided in an embodiment of the present application.

[0049] Reference numerals:

[0050] Testing device 500, first processing module 510, second processing module 520, third processing module 530,

[0051] Environmental chamber 610 , temperature monitoring device 611 , current detection device 621 , voltage detection device 622 , first power supply 631 , second power supply 632 , bypass diode 700 . DETAILED DESCRIPTION

[0052] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0053] Reference below Figure 1-Figure 6 A method for testing a bypass diode 700 , a device 500 for testing a bypass diode 700 , and a system for testing a bypass diode 700 according to an embodiment of the present application are described.

[0054] The test method of the bypass diode 700 provided in the embodiment of the present application can be executed by an electronic device or a functional module or functional entity in the electronic device that can implement the test method of the bypass diode 700.

[0055] like Figure 1As shown, the test method of the bypass diode 700 according to the embodiment of the present application includes step 110 , step 120 and step 130 .

[0056] Step 110 , obtaining the forward voltage drop values ​​of the bypass diode 700 to be tested at different temperatures within the target temperature range, and determining the voltage drop-junction temperature relationship between the forward voltage drop and the junction temperature of the bypass diode 700 .

[0057] The target temperature range may be a range in which the junction temperature of the bypass diode 700 may fluctuate. The target temperature range is related to the device characteristics of the bypass diode 700 itself, and bypass diodes 700 of different specifications have different target temperature ranges.

[0058] The forward voltage drop refers to the forward voltage drop of the bypass diode 700 under a specified forward current, that is, the minimum forward voltage at which the bypass diode 700 can be turned on, reflecting the voltage characteristic of the bypass diode 700 when it is forward-conducting.

[0059] In this embodiment, multiple target temperature values ​​are selected within the target temperature range, and the forward voltage drop values ​​of the bypass diode 700 corresponding to each temperature are measured to obtain the corresponding relationship between the target temperature value and the forward voltage drop value within the target temperature range, that is, the voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode 700 is obtained.

[0060] It is understandable that the selection of multiple target temperature values ​​within the target temperature range may be performed according to a certain data selection rule or may be randomly selected.

[0061] For example, the target temperature range is 20°C-200°C.

[0062] In this embodiment, the forward voltage drop values ​​corresponding to 30°C, 40°C, 50°C...190°C, and 200°C can be obtained according to the data collection rule of a temperature difference of 10°C, wherein 30°C corresponds to a forward voltage drop value VF1, 40°C corresponds to a forward voltage drop value VF2, 50°C corresponds to a forward voltage drop value VF3...190°C corresponds to a forward voltage drop value VF17, and 200°C corresponds to a forward voltage drop value VF18.

[0063] According to the target temperature value within the target temperature range and the forward voltage drop value corresponding to the target temperature value, the voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode 700 can be fitted.

[0064] In actual implementation, the voltage drop-junction temperature relationship can be represented as a linear function, a quadratic function, or a multi-time function.

[0065] For example, according to the data collection rule with a temperature difference of 10°C, after measuring the forward voltage drop values ​​corresponding to 18 target temperature values ​​within the target temperature range, the function expression of the voltage drop junction temperature relationship is obtained through linear fitting as follows:

[0066] Tj=k1×VF+b1

[0067] Wherein, Tj represents the junction temperature of the bypass diode 700, VF represents the forward voltage drop of the bypass diode 700, and k1 and b1 are function parameters obtained by fitting.

[0068] Step 120 , obtaining the reverse withstand voltage extreme values ​​of the bypass diode 700 at different temperatures within the target temperature range, and determining the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode 700 .

[0069] The reverse withstand voltage limit refers to the maximum reverse withstand voltage that the bypass diode 700 can withstand at a certain temperature. When the reverse voltage applied to the bypass diode 700 at this temperature exceeds the reverse withstand voltage limit, the bypass diode 700 may fail due to breakdown.

[0070] In this embodiment, multiple target temperature values ​​are selected within the target temperature range, and the reverse withstand voltage extreme values ​​corresponding to the bypass diode 700 at each temperature are measured to obtain the corresponding relationship between the target temperature value and the reverse withstand voltage extreme value within the target temperature range, that is, the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode 700 is obtained.

[0071] In actual implementation, the multiple target temperature values ​​selected within the target temperature range when measuring the reverse withstand voltage extreme value may be the same as the multiple target temperature values ​​selected within the target temperature range when measuring the forward voltage drop value, that is, when obtaining the reverse withstand voltage extreme value and the forward voltage drop value, multiple target temperature values ​​are selected within the target temperature range for measurement according to the same data selection rule.

[0072] For example, the target temperature range is 20°C-200°C.

[0073] In this embodiment, according to the temperature difference of 10°C, the reverse withstand voltage extreme values ​​corresponding to 30°C, 40°C, 50°C...190°C, and 200°C can be obtained, wherein 30°C corresponds to the reverse withstand voltage extreme value VB1, 40°C corresponds to the reverse withstand voltage extreme value VB2, 50°C corresponds to the reverse withstand voltage extreme value VB3...190°C corresponds to the reverse withstand voltage extreme value VB17, and 200°C corresponds to the reverse withstand voltage extreme value VB18.

[0074] According to the target temperature value within the target temperature range and the reverse withstand voltage extreme value corresponding to the target temperature value, the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode 700 can be fitted.

[0075] In actual implementation, the junction temperature-voltage withstand relationship can be represented by a linear function, a quadratic function, or a multi-time function.

[0076] For example, according to the data collection rule with a temperature difference of 10°C, after measuring the reverse withstand voltage extremes corresponding to 18 target temperature values ​​within the target temperature range, the function expression of the junction temperature withstand voltage relationship is obtained through linear fitting as follows:

[0077] VB=k2×Tj+b2

[0078] Wherein, Tj represents the junction temperature of the bypass diode 700, VB represents the reverse withstand voltage of the bypass diode 700, and k2 and b2 are function parameters obtained by fitting.

[0079] It can be understood that the multiple target temperature values ​​selected within the target temperature range when measuring the reverse withstand voltage extreme value and the multiple target temperature values ​​selected within the target temperature range when measuring the forward voltage drop value may also be different. The target temperature value is selected within the target temperature range, and the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship that are consistent with the temperature range are fitted.

[0080] Step 130 : Based on the component performance parameters of the bypass diode 700 , according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, determine the test result of the bypass diode 700 .

[0081] The component performance parameters of the bypass diode 700 refer to the electrical performance parameters during the application process when the bypass diode 700 is connected in parallel with the photovoltaic component.

[0082] In actual implementation, the component performance parameters of the bypass diode 700 may include parameters such as component short-circuit current value, component turn-on voltage parameter, and diode voltage drop extreme value corresponding to the diode junction temperature threshold.

[0083] The component short-circuit current value can represent the theoretical maximum current when the bypass diode 700 works in the forward direction, that is, the component short-circuit current Isc of the component connected in parallel with the bypass diode 700.

[0084] The component open-circuit voltage parameter can characterize the theoretical maximum bias voltage when the bypass diode 700 works in reverse. The component open-circuit voltage parameter can be determined based on the component open-circuit voltage of the component connected in parallel with the bypass diode 700. For example, the component open-circuit voltage parameter can be 1 / 3Voc, where Voc is the component open-circuit voltage.

[0085] The diode junction temperature threshold refers to the maximum junction temperature Tj that the bypass diode 700 can reach in actual operation. max , for example, the diode junction temperature threshold is 75°C.

[0086] In this embodiment, the diode voltage drop extreme value is the forward voltage drop VF0 corresponding to the bypass diode 700 when operating in a temperature environment corresponding to the diode junction temperature threshold, that is, the maximum forward voltage drop that the bypass diode 700 can achieve in actual operation.

[0087] It can be understood that the voltage drop junction temperature relationship represents the law of how the forward voltage drop changes with the junction temperature during the operation of the bypass diode 700, and the junction temperature withstand voltage relationship represents the law of how the reverse withstand voltage changes with the junction temperature during the operation of the bypass diode 700.

[0088] In this embodiment, according to the law of how the forward voltage drop and / or reverse withstand voltage change with the junction temperature during the operation of the bypass diode 700, combined with the component performance parameters corresponding to the bypass diode 700 when it is actually connected in parallel with the component, it can be determined whether the changes in the forward voltage drop and reverse withstand voltage of the bypass diode 700 with the junction temperature can meet the requirements corresponding to the component performance parameters, and the safety and reliability of the bypass diode 700 when the component works for a long time can be quickly and accurately determined.

[0089] In the related art, the diode thermal runaway test method is: after passing the rated current in the forward direction for a certain period of time at a certain temperature (the diode works forward when simulating a hot spot), switch to the reverse bias state. If the reverse leakage current and the diode temperature are both in a decreasing state, the test passes. Each test obtains a set of current and bias parameters. If you want to see the reverse limit capability of the diode under a certain forward current, you need to set up multiple sets of tests for continuous exploration and load testing. In addition, this type of test method is difficult to accurately judge the safety and reliability of the diode during long-term operation of the component.

[0090] In the embodiment of the present application, the forward voltage drop value and the reverse withstand voltage extreme value of the bypass diode 700 at different temperatures within the target temperature range are measured, and the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship of the bypass diode 700 are constructed. By using the law of the electrical performance of the bypass diode 700 characterized by at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship changing with the junction temperature, combined with the component performance parameters corresponding to the bypass diode 700 when the bypass diode 700 is actually connected in parallel with the component, it can be determined whether the bypass diode 700 can meet the requirements corresponding to the component performance parameters, which is convenient for detecting the reverse limit capacity of the bypass diode 700 under the forward current. The test process is simple, and the safety and reliability of the bypass diode 700 can be quickly and accurately determined when the component works for a long time.

[0091] According to the testing method of the bypass diode 700 provided in the embodiment of the present application, through the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship of the bypass diode 700, combined with the component performance parameters corresponding to the bypass diode 700 when the bypass diode 700 is actually connected in parallel with the component, it is judged whether the bypass diode 700 can meet the requirements corresponding to the component performance parameters. The testing process is simple and can quickly and accurately judge the safety and reliability of the bypass diode 700 when the component is working for a long time.

[0092] In some embodiments, the component performance parameter includes a component turn-on voltage parameter of the bypass diode 700, such as Figure 2 As shown, determining the test result of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship may include:

[0093] Step 131, determining a first operating temperature of the bypass diode 700 based on a component opening voltage parameter and a junction temperature withstand voltage relationship;

[0094] Step 132 : Compare the first operating temperature with the operating temperature threshold of the bypass diode 700 , and determine a test result of the bypass diode 700 according to the comparison result.

[0095] It should be noted that the junction temperature-voltage relationship characterizes the law of how the reverse voltage of the bypass diode 700 changes with temperature, and the component turn-on voltage parameter characterizes the theoretical maximum bias voltage when the bypass diode 700 works in reverse. The component turn-on voltage parameter is substituted into the junction temperature-voltage relationship to calculate the first operating temperature of the bypass diode 700. The first operating temperature can characterize the maximum temperature that the bypass diode 700 can withstand when working in reverse at the theoretical maximum bias voltage.

[0096] The operating temperature threshold of the bypass diode 700 refers to the maximum junction temperature allowed when the bypass diode 700 is working. For example, the operating temperature threshold of the bypass diode 700 is 200° C., which means that the maximum junction temperature of the bypass diode 700 cannot exceed 200° C.

[0097] It should be noted that the operating temperature threshold is the maximum junction temperature allowed when the bypass diode 700 is working, the diode junction temperature threshold is the maximum junction temperature that the bypass diode 700 can reach in actual operation, the diode junction temperature threshold is less than the operating temperature threshold, and the maximum value of the target temperature range can be the operating temperature threshold.

[0098] In this embodiment, the calculated first operating temperature of the bypass diode 700 is compared with the operating temperature threshold to determine whether the bypass diode 700 meets the component performance requirements, and to quickly and accurately determine the safety and reliability of the bypass diode 700 when the component works for a long time.

[0099] In some embodiments, comparing the first operating temperature with an operating temperature threshold of the bypass diode 700, and determining a test result of the bypass diode 700 according to the comparison result, includes:

[0100] When the first operating temperature is greater than the operating temperature threshold, it is determined that the bypass diode 700 has passed the test.

[0101] In this embodiment, when the first operating temperature is greater than the operating temperature threshold, it indicates that the maximum temperature that the bypass diode 700 can withstand when working in reverse under the theoretical maximum bias voltage is greater than the maximum junction temperature allowed when the bypass diode 700 is working. The bypass diode 700 can meet the component performance requirements and has a certain safety margin, and can be applied to photovoltaic components corresponding to the component opening voltage parameters.

[0102] For example, the component open-circuit voltage parameter is 1 / 3Voc, where Voc is the component open-circuit voltage. Substitute 1 / 3Voc into the function expression of the junction temperature and withstand voltage relationship: VB=k2×Tj+b2.

[0103] Assuming VB=1 / 3Voc, the maximum temperature that the bypass diode 700 can withstand when the reverse bias voltage is 1 / 3Voc is calculated, that is, the first operating temperature T0. The operating temperature threshold of the bypass diode 700 is 200°C.

[0104] If T0 is greater than 200° C., it can be quickly determined that the bypass diode 700 meets the performance parameter requirements of the component and has a safety margin, and can be applied to a photovoltaic component with an open-circuit voltage of Voc.

[0105] It can be understood that when the first operating temperature is less than or equal to the operating temperature threshold, it indicates that the maximum temperature that the bypass diode 700 can withstand when working in reverse under the theoretical maximum bias is less than or equal to the maximum junction temperature allowed when the bypass diode 700 is working. The bypass diode 700 may not be able to meet the performance requirements of the component. When the component works for a long time, the safety and reliability of the bypass diode 700 are low.

[0106] In some embodiments, the component performance parameters include the component opening voltage parameter of the bypass diode 700 and the diode voltage drop extreme value corresponding to the bypass diode 700 at the diode junction temperature threshold, such as Figure 3 As shown, according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, determining the test result of the bypass diode 700 includes:

[0107] Step 133: Determine the first operating temperature of the bypass diode 700 based on the component opening voltage parameter and the junction temperature withstand voltage relationship;

[0108] Step 134, determining a second operating temperature of the bypass diode 700 based on the diode voltage drop extreme value and the voltage drop junction temperature relationship;

[0109] Step 135 : Compare the first operating temperature and the second operating temperature, and determine a test result of the bypass diode 700 according to the comparison result.

[0110] In this embodiment, the component opening voltage parameter is substituted into the junction temperature and withstand voltage relationship, and the maximum temperature that the bypass diode 700 can withstand when working in reverse at the theoretical maximum bias voltage is calculated, that is, the first operating temperature; the diode voltage drop extreme value is substituted into the voltage drop junction temperature relationship, and the maximum temperature that the bypass diode 700 can reach when the maximum forward voltage drop is reached under the condition of long-term operation at the maximum forward current (i.e., the component short-circuit current) is calculated, that is, the second operating temperature.

[0111] Compare the maximum temperature that the bypass diode 700 can withstand when working in reverse under the theoretical maximum bias and the maximum temperature corresponding to the maximum forward voltage drop reached by the bypass diode 700, and determine whether the second highest operating temperature that can be reached exceeds the first highest operating temperature that can be tolerated, and then determine whether the bypass diode 700 meets the component performance requirements, and quickly and accurately determine the safety and reliability of the bypass diode 700 when the component works for a long time.

[0112] In some embodiments, comparing the first operating temperature with the second operating temperature and determining the test result of the bypass diode 700 according to the comparison result may include:

[0113] When the first operating temperature is greater than or equal to the second operating temperature, it is determined that the bypass diode 700 has passed the test.

[0114] In this embodiment, when the first operating temperature is greater than or equal to the second operating temperature, it indicates that the maximum temperature that the bypass diode 700 can withstand when working in reverse at the theoretical maximum bias is greater than or equal to the maximum temperature that the bypass diode 700 can reach under the maximum forward voltage drop, and the bypass diode 700 can meet the component performance requirements and have a certain safety margin.

[0115] For example, the component open-circuit voltage parameter is 1 / 3Voc, where Voc is the component open-circuit voltage. Substitute 1 / 3Voc into the function expression of the junction temperature and withstand voltage relationship: VB=k2×Tj+b2.

[0116] Assuming VB=1 / 3Voc, the maximum temperature that the bypass diode 700 can withstand when the reverse bias voltage is 1 / 3Voc is calculated, that is, the first operating temperature T0.

[0117] The diode junction temperature threshold Tj that the bypass diode 700 can reach in actual operation max The temperature is 75℃, and the diode voltage drop limit is VF0 in a temperature environment of 75℃.

[0118] Substitute VF0 into the functional expression of the voltage drop and junction temperature relationship: Tj=k1×VF+b1, let VF=VF0, and calculate the second operating temperature Tj0.

[0119] Comparing the relationship between T0 and Tj0, if T0<Tj0, the bypass diode 700 does not meet the requirements of the component performance parameters and cannot be applied to the component; if T0=Tj0, the bypass diode 700 just meets the requirements of the component performance parameters and can be applied to the component; if T0>Tj0, the bypass diode 700 meets the requirements of the component performance parameters and has a safety margin, and can be applied to photovoltaic components with an open circuit voltage of Voc.

[0120] In some embodiments, the component performance parameters include the component opening voltage parameter of the bypass diode 700 and the diode voltage drop extreme value corresponding to the bypass diode 700 at the diode junction temperature threshold, such as Figure 4 As shown, according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, determining the test result of the bypass diode 700 includes:

[0121] Step 136, determining the voltage drop and withstand voltage relationship of the bypass diode 700 based on the voltage drop and junction temperature relationship and the junction temperature and withstand voltage relationship;

[0122] Step 137, determining a first target withstand voltage of the bypass diode 700 based on the diode voltage drop extreme value and the voltage drop withstand voltage relationship;

[0123] Step 138: compare the first target withstand voltage and the component start-up voltage parameter, and determine the test result of the bypass diode 700 according to the comparison result.

[0124] It can be understood that the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship have the same variable junction temperature. By converting the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, the voltage drop withstand voltage relationship between the reverse withstand voltage and the forward voltage drop of the bypass diode 700 can be obtained.

[0125] For example, the function expression of the voltage drop junction temperature relationship is Tj=k1×VF+b1, and the function expression of the junction temperature withstand voltage relationship is VB=k2×Tj+b2. By converting the two function expressions, the function expression of the voltage drop withstand voltage relationship is as follows:

[0126] VB=k1×k2×VF+k2×b1+b2

[0127] Wherein, VB represents the reverse withstand voltage of the bypass diode 700, VF represents the forward voltage drop of the bypass diode 700, and k1, b1, k2 and b2 are function parameters obtained by fitting.

[0128] In this embodiment, the diode voltage drop extreme value is substituted into the voltage drop withstand voltage relationship to calculate the maximum voltage that the bypass diode 700 can withstand when it is switched to reverse bias instantaneously under the condition of long-term maximum forward current operation, that is, the first target withstand voltage.

[0129] By comparing the first target withstand voltage that the bypass diode 700 can withstand under extreme conditions with the component opening voltage parameter corresponding to the photovoltaic component in parallel with the bypass diode 700, it is possible to determine whether the bypass diode 700 meets the component performance requirements and quickly and accurately determine the safety and reliability of the bypass diode 700 when the component works for a long time.

[0130] In some embodiments, comparing the first target withstand voltage with the component turn-on voltage parameter, and determining the test result of the bypass diode 700 according to the comparison result may include:

[0131] When the first target withstand voltage is greater than or equal to the component opening voltage parameter, it is determined that the bypass diode 700 has passed the test.

[0132] In this embodiment, when the first target withstand voltage that the bypass diode 700 can withstand under extreme conditions is greater than or equal to the component opening voltage parameter, it indicates that the bypass diode 700 can meet the component performance requirements and has a certain safety margin.

[0133] For example, the diode junction temperature threshold Tj that the bypass diode 700 can reach in actual operation is max The temperature is 75℃. Under the temperature environment of 75℃, the extreme value of the diode voltage drop is VF0. The component opening voltage parameter is 1 / 3Voc, and Voc is the component open circuit voltage.

[0134] Substituting VF0 into the function expression of the voltage drop and withstand voltage relationship VB=k1×k2×VF+k2×b1+b2, we can obtain the first target withstand voltage VB0 that the bypass diode 700 can withstand under extreme conditions. VB0 is the maximum voltage that the bypass diode 700 can withstand when it is instantly switched to reverse bias under long-term operation at the maximum forward current.

[0135] Comparing the relationship between VB0 and 1 / 3Voc, if VB0<1 / 3Voc, the bypass diode 700 does not meet the requirements of the component performance parameters and cannot be applied to the component; if VB0=1 / 3Voc, the bypass diode 700 just meets the requirements of the component performance parameters and can be applied to the component; if VB0>1 / 3Voc, the bypass diode 700 meets the requirements of the component performance parameters and has a safety margin, and can be applied to photovoltaic components with an open circuit voltage of Voc.

[0136] In some embodiments, obtaining the forward voltage drop value of the bypass diode 700 to be tested at different temperatures within the target temperature range includes:

[0137] When the temperature of the bypass diode 700 reaches the target temperature value within the target temperature range, a first pulse current is applied to the bypass diode 700 to obtain a forward voltage drop value corresponding to the target temperature value. The magnitude of the first pulse current is the component short-circuit current value corresponding to the bypass diode 700.

[0138] In this embodiment, when measuring the forward voltage drop value corresponding to a certain target temperature value, the temperature of the bypass diode 700 is controlled to reach the target temperature value and maintained at the target temperature value for a certain period of time so that the junction temperature of the bypass diode 700 reaches the target temperature value and stabilizes.

[0139] For example, the target temperature value is 30° C., and the temperature of the bypass diode 700 is controlled to reach 30° C. and maintained at 30° C. for at least 40 minutes. At this time, the junction temperature of the bypass diode 700 reaches 30° C. and is stable.

[0140] In this embodiment, when the temperature of the bypass diode 700 reaches the target temperature value and stabilizes, a first pulse current with a component short-circuit current value is applied to the bypass diode 700, and the voltage waveform at both ends of the bypass diode 700 is collected by the voltage detection device 622 to obtain the forward voltage drop value corresponding to the target temperature value.

[0141] In actual implementation, multiple voltage drop values ​​of the device to which the first pulse current is applied may be recorded, and an average value of the multiple voltage drop values ​​may be calculated as the forward voltage drop value corresponding to the target temperature value.

[0142] For example, the bypass diode 700 is connected to the second power supply 632, and the second power supply 632 selects the pulse current output mode, closes the loop for a short time and then immediately disconnects, applying a first pulse current with a current magnitude of the component short-circuit current value Isc and a pulse width of up to 1 ms to the bypass diode 700.

[0143] In this embodiment, the voltage waveform across the bypass diode 700 is collected by the voltage detection device 622, and the voltage drop value of the bypass diode 700 within 1 ms of power-on is recorded. A voltage drop value is taken every 0.1 ms, and the average value of multiple voltage drop values ​​is calculated as the forward voltage drop value corresponding to the target temperature value.

[0144] It should be noted that under the first pulse current of the component short-circuit current value, the forward voltage drop values ​​corresponding to each target temperature value are measured, and the obtained voltage drop junction temperature relationship can characterize the law of change of the forward voltage drop with the junction temperature when the bypass diode 700 works under the maximum forward current.

[0145] In some embodiments, obtaining the reverse withstand voltage extreme value of the bypass diode 700 at different temperatures within the target temperature range includes:

[0146] When the temperature of the bypass diode 700 reaches the target temperature value within the target temperature range, a reverse voltage is applied to the bypass diode 700, the current output current of the bypass diode 700 is obtained and the reverse voltage is gradually increased, it is determined that the current output current is greater than or equal to the first current threshold, and the reverse withstand voltage extreme value corresponding to the target temperature value is obtained.

[0147] It is understandable that when measuring the reverse withstand voltage limit corresponding to a certain target temperature value, the temperature of the bypass diode 700 is controlled to reach the target temperature value and maintained at the target temperature value for a certain period of time so that the junction temperature of the bypass diode 700 reaches the target temperature value and stabilizes.

[0148] In this embodiment, when the temperature of the bypass diode 700 reaches the target temperature value and stabilizes, a reverse voltage is applied to the bypass diode 700 to obtain the current output current of the bypass diode 700. It is determined whether the bypass diode 700 is broken down based on the current output current and the first current threshold. If it is not broken down, the reverse voltage is gradually increased until the current output current is greater than or equal to the first current threshold, and the reverse withstand voltage limit corresponding to the target temperature value is obtained.

[0149] The first current threshold is a preset current critical value. When the current output current of the bypass diode 700 is greater than or equal to the first current threshold, it indicates that the bypass diode 700 has failed due to breakdown.

[0150] For example, the bypass diode 700 is connected to the first power supply 631, the first power supply 631 selects the constant voltage output mode, sets the initial reverse voltage to 10V, and the first current threshold is 10A.

[0151] 6315s after the first power supply is turned on, if the current output current of the bypass diode 700 collected by the current detection device 621 is less than 10A, the bypass diode 700 is determined to be normal; if the current output current of the bypass diode 700 is greater than or equal to 10A, the bypass diode 700 is determined to have broken down and failed.

[0152] If the bypass diode 700 is normal when the reverse voltage is 10V, the reverse voltage is increased by 0.5V each time until the bypass diode 700 breaks down and fails, thereby obtaining the reverse withstand voltage extreme value corresponding to the target temperature value.

[0153] In some embodiments, the target temperature range is 20° C.-200° C., and the diode junction temperature threshold of the bypass diode 700 is within the target temperature range.

[0154] The target temperature range may be a range in which the junction temperature of the bypass diode 700 may fluctuate. The target temperature range is related to the device characteristics of the bypass diode 700 itself, and the target temperature ranges of bypass diodes 700 of different specifications are different.

[0155] In actual implementation, the maximum value of the target temperature range may be the highest junction temperature allowed when the bypass diode 700 is operating. For example, the operating temperature threshold of the bypass diode 700 is 200° C.

[0156] It is understandable that the operating temperature threshold is the maximum junction temperature allowed when the bypass diode 700 is working, the diode junction temperature threshold is the maximum junction temperature that the bypass diode 700 can reach in actual operation, and the diode junction temperature threshold is less than the operating temperature threshold.

[0157] The embodiment of the present application also provides a testing device 500 for a bypass diode 700 .

[0158] like Figure 5 As shown, the testing device 500 comprises:

[0159] The first processing module 510 is used to obtain the forward voltage drop value of the bypass diode 700 to be tested at different temperatures within the target temperature range, and determine the voltage drop-junction temperature relationship between the forward voltage drop and the junction temperature of the bypass diode 700;

[0160] The second processing module 520 is used to obtain the reverse withstand voltage extreme value of the bypass diode 700 at different temperatures within the target temperature range, and determine the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode 700;

[0161] The third processing module 530 is used to determine the test result of the bypass diode 700 based on the component performance parameters of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

[0162] According to the test device 500 of the bypass diode 700 provided in the embodiment of the present application, through the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship of the bypass diode 700, combined with the component performance parameters corresponding to the bypass diode 700 when the bypass diode 700 is actually connected in parallel with the component, it is judged whether the bypass diode 700 can meet the requirements corresponding to the component performance parameters. The test process is simple, and the safety and reliability of the bypass diode 700 when the component works for a long time can be judged quickly and accurately.

[0163] In some embodiments, the component performance parameter includes a component opening voltage parameter of the bypass diode 700. The third processing module 530 is used to determine the test result of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, including:

[0164] Determine the first operating temperature of the bypass diode 700 based on the component opening voltage parameter and the junction temperature withstand voltage relationship;

[0165] The first operating temperature is compared with an operating temperature threshold of the bypass diode 700 , and a test result of the bypass diode 700 is determined according to the comparison result.

[0166] In some embodiments, the third processing module 530 is used to compare the first operating temperature with the operating temperature threshold of the bypass diode 700, and determine the test result of the bypass diode 700 according to the comparison result, including:

[0167] When the first operating temperature is greater than the operating temperature threshold, it is determined that the bypass diode 700 has passed the test.

[0168] In some embodiments, the component performance parameter includes a component opening voltage parameter of the bypass diode 700 and a diode voltage drop extreme value corresponding to the bypass diode 700 at a diode junction temperature threshold. The third processing module 530 is used to determine the test result of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, including:

[0169] Determine the first operating temperature of the bypass diode 700 based on the component opening voltage parameter and the junction temperature withstand voltage relationship;

[0170] Determine a second operating temperature of the bypass diode 700 based on the diode voltage drop extreme value and the voltage drop junction temperature relationship;

[0171] The first operating temperature is compared with the second operating temperature, and a test result of the bypass diode 700 is determined according to the comparison result.

[0172] In some embodiments, the third processing module 530 is used to compare the first operating temperature with the second operating temperature, and determine the test result of the bypass diode 700 according to the comparison result, including:

[0173] When the first operating temperature is greater than or equal to the second operating temperature, it is determined that the bypass diode 700 has passed the test.

[0174] In some embodiments, the component performance parameter includes a component opening voltage parameter of the bypass diode 700 and a diode voltage drop extreme value corresponding to the bypass diode 700 at a diode junction temperature threshold. The third processing module 530 is used to determine the test result of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, including:

[0175] Based on the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, determine the voltage drop withstand voltage relationship of the bypass diode 700;

[0176] Determine a first target withstand voltage of the bypass diode 700 based on the diode voltage drop extreme value and the voltage drop withstand voltage relationship;

[0177] The first target withstand voltage is compared with the component turn-on voltage parameter, and the test result of the bypass diode 700 is determined according to the comparison result.

[0178] In some embodiments, the third processing module 530 is used to compare the first target withstand voltage and the component start-up voltage parameter, and determine the test result of the bypass diode 700 according to the comparison result, including:

[0179] When the first target withstand voltage is greater than or equal to the component opening voltage parameter, it is determined that the bypass diode 700 has passed the test.

[0180] In some embodiments, the first processing module 510 is used to obtain the forward voltage drop value of the bypass diode 700 to be tested at different temperatures within the target temperature range, including:

[0181] When the temperature of the bypass diode 700 reaches the target temperature value within the target temperature range, a first pulse current is applied to the bypass diode 700 to obtain a forward voltage drop value corresponding to the target temperature value. The magnitude of the first pulse current is the component short-circuit current value corresponding to the bypass diode 700.

[0182] In some embodiments, the second processing module 520 is used to obtain the reverse withstand voltage extreme value of the bypass diode 700 at different temperatures within the target temperature range, including:

[0183] When the temperature of the bypass diode 700 reaches the target temperature value within the target temperature range, a reverse voltage is applied to the bypass diode 700, the current output current of the bypass diode 700 is obtained and the reverse voltage is gradually increased, it is determined that the current output current is greater than or equal to the first current threshold, and the reverse withstand voltage extreme value corresponding to the target temperature value is obtained.

[0184] In some embodiments, the target temperature range is 20° C.-200° C., and the diode junction temperature threshold of the bypass diode 700 is within the target temperature range.

[0185] The embodiment of the present application also provides a test system for the bypass diode 700 .

[0186] like Figure 6 As shown, the test system includes an environmental chamber 610, a data acquisition device and a power supply device, and a test device 500 for the bypass diode 700 as described above.

[0187] The environmental chamber 610 is used to place the bypass diode 700 to be tested and provide a temperature environment within a target temperature range for the bypass diode 700 .

[0188] In this embodiment, a temperature monitoring device 611 may be provided in the environmental chamber 610 , and the temperature monitoring device 611 may detect the temperature of the bypass diode 700 in real time to reflect whether the bypass diode 700 has reached a target temperature value within a target temperature range.

[0189] It is understandable that the environmental chamber 610 can also provide the bypass diode 700 with a required humidity environment.

[0190] In this embodiment, a data acquisition device and a power supply device are connected to the bypass diode 700 , and the data acquisition device is used to collect current and voltage data of the bypass diode 700 when the power supply device is supplying power.

[0191] The power supply device is connected to the bypass diode 700, and the power supply device provides different power supply output modes for the bypass diode 700. The data acquisition device can measure the current and voltage data of the bypass diode 700 to obtain parameters such as the forward voltage drop value and reverse withstand voltage limit of the bypass diode 700 at different temperatures within the target temperature range.

[0192] In actual implementation, the data acquisition device may include a current detection device 621 and a voltage detection device 622 , and the power supply device may include a first power supply 631 and a second power supply 632 .

[0193] The first power supply 631 may provide a constant voltage output mode to measure the reverse withstand voltage limit of the bypass diode 700 at different temperatures within a target temperature range.

[0194] The second power supply 632 can provide a constant current output mode, a pulse current output mode, etc. to measure the forward voltage drop value of the bypass diode 700 at different temperatures within the target temperature range.

[0195] The test device 500 is connected to the data acquisition device. The test device 500 can receive the data collected by the data acquisition device, obtain the forward voltage drop value and the reverse withstand voltage extreme value of the bypass diode 700 at different temperatures within the target temperature range, construct the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship, and based on the component performance parameters of the bypass diode 700, determine the test result of the bypass diode 700 according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

[0196] According to the test system of the bypass diode 700 provided in the embodiment of the present application, through the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship of the bypass diode 700, combined with the component performance parameters corresponding to the bypass diode 700 when the bypass diode 700 is actually connected in parallel with the component, it is judged whether the bypass diode 700 can meet the requirements corresponding to the component performance parameters. The test process is simple and can quickly and accurately judge the safety and reliability of the bypass diode 700 when the component works for a long time.

[0197] A specific embodiment is described below.

[0198] The bypass diode 700 to be tested is placed in the environmental chamber 610 and connected to the data acquisition equipment and the power supply device. The component performance parameters of the bypass diode 700 are first obtained, including the theoretical maximum current of the bypass diode 700 when working in the forward direction (component short-circuit current Isc), the theoretical maximum bias voltage of the bypass diode 700 when working in the reverse direction (1 / 3 component open-circuit voltage Voc), and the maximum forward voltage drop that the bypass diode 700 can achieve in actual work (diode voltage drop extreme value VF0).

[0199] The temperature of the environmental box 610 is adjusted to the diode junction temperature threshold of 75°C. The temperature monitoring device 611 monitors the ambient temperature. After the temperature stabilizes, it is maintained at 75°C for at least 40 minutes. At this time, the junction temperature of the bypass diode 700 reaches 75°C and stabilizes. The second power supply 632 selects the constant current output mode with a current of Isc. The closed loop is energized for 1 hour. The voltage detection device 622 detects the voltage drop VF0 across the bypass diode 700. The circuit is disconnected after the test.

[0200] In this embodiment, the target temperature range is 20°C-200°C. According to the data collection rule with a temperature difference of 10°C, the forward voltage drop values ​​and reverse withstand voltage extremes corresponding to 30°C, 40°C, 50°C...190°C, and 200°C are obtained.

[0201] The temperature of the bypass diode 700 is controlled to reach 30°C and maintained at 30°C for at least 40 minutes. The second power supply 632 selects the pulse current output mode, closes the loop for a short time and then disconnects immediately, and applies a first pulse current with a current magnitude of the component short-circuit current value Isc and a pulse width of up to 1ms to the bypass diode 700.

[0202] The voltage waveform across the bypass diode 700 is collected by the voltage detection device 622, and the voltage drop value of the bypass diode 700 within 1ms of power-on is recorded. A voltage drop value is taken every 0.1ms, and the average value of multiple voltage drop values ​​is calculated as the forward voltage drop value corresponding to 30°C.

[0203] Among them, 30℃ corresponds to the forward voltage drop value VF1, 40℃ corresponds to the forward voltage drop value VF2, 50℃ corresponds to the forward voltage drop value VF3…190℃ corresponds to the forward voltage drop value VF17, and 200℃ corresponds to the forward voltage drop value VF18.

[0204] After measuring the forward voltage drop values ​​corresponding to 18 target temperature values ​​within the target temperature range, the function expression of the voltage drop junction temperature relationship is obtained through linear fitting as follows:

[0205] Tj=k1×VF+b1

[0206] Wherein, Tj represents the junction temperature of the bypass diode 700, VF represents the forward voltage drop of the bypass diode 700, and k1 and b1 are function parameters obtained by fitting.

[0207] The temperature of the bypass diode 700 is controlled to reach 30° C. and maintained at 30° C. for at least 40 minutes. The first power supply 631 selects a constant voltage output mode, sets an initial reverse voltage of 10V, and a first current threshold of 10A.

[0208] 6315s after the first power supply is turned on, if the current output current of the bypass diode 700 collected by the current detection device 621 is less than 10A, the bypass diode 700 is determined to be normal; if the current output current of the bypass diode 700 is greater than or equal to 10A, the bypass diode 700 is determined to have broken down and failed.

[0209] If the bypass diode 700 is normal when the reverse voltage is 10V, the reverse voltage is increased by 0.5V each time until the bypass diode 700 breaks down and fails, thereby obtaining the reverse withstand voltage extreme value corresponding to the target temperature value.

[0210] Obtain the reverse withstand voltage extreme values ​​corresponding to 30℃, 40℃, 50℃...190℃, 200℃, wherein 30℃ corresponds to the reverse withstand voltage extreme value VB1, 40℃ corresponds to the reverse withstand voltage extreme value VB2, 50℃ corresponds to the reverse withstand voltage extreme value VB3...190℃ corresponds to the reverse withstand voltage extreme value VB17, and 200℃ corresponds to the reverse withstand voltage extreme value VB18.

[0211] After measuring the reverse withstand voltage extremes corresponding to 18 target temperature values ​​within the target temperature range, the function expression of the junction temperature withstand voltage relationship is obtained through linear fitting as follows:

[0212] VB=k2×Tj+b2

[0213] Wherein, Tj represents the junction temperature of the bypass diode 700, VB represents the reverse withstand voltage of the bypass diode 700, and k2 and b2 are function parameters obtained by fitting.

[0214] The function expression of the voltage drop junction temperature relationship is Tj=k1×VF+b1, and the function expression of the junction temperature withstand voltage relationship is VB=k2×Tj+b2. By converting the two function expressions, the function expression of the voltage drop withstand voltage relationship is as follows:

[0215] VB=k1×k2×VF+k2×b1+b2

[0216] Wherein, VB represents the reverse withstand voltage of the bypass diode 700, VF represents the forward voltage drop of the bypass diode 700, and k1, b1, k2 and b2 are function parameters obtained by fitting.

[0217] In actual implementation, the bypass diode 700 may be tested in at least one of the following ways:

[0218] First, VF0 is substituted into VB=k1×k2×VF+k2×b1+b2 to obtain the first target withstand voltage VB0 that the bypass diode 700 can withstand under extreme conditions, and the relationship between VB0 and 1 / 3Voc is compared.

[0219] If VB0 is less than 1 / 3Voc, the bypass diode 700 does not meet the requirements of the component performance parameters and cannot be applied to the component; if VB0 is equal to 1 / 3Voc, the bypass diode 700 just meets the requirements of the component performance parameters and can be applied to the component; if VB0 is greater than 1 / 3Voc, the bypass diode 700 meets the requirements of the component performance parameters and has a safety margin, and can be applied to photovoltaic components with an open-circuit voltage of Voc.

[0220] Secondly, by substituting 1 / 3Voc into VB=k2×Tj+b2, the maximum temperature that the bypass diode 700 can withstand when the reverse bias voltage is 1 / 3Voc is calculated to be the first operating temperature T0, and T0 is compared with the operating temperature threshold of the bypass diode 700, which is 200°C.

[0221] If T0 is greater than 200° C., it can be determined that the bypass diode 700 meets the component performance parameter requirements and has a safety margin, and can be applied to the component.

[0222] Third, VF0 is substituted into Tj=k1×VF+b1, the second operating temperature Tj0 is calculated, and the relationship between T0 and Tj0 is compared.

[0223] If T0<Tj0, the bypass diode 700 does not meet the requirements of the component performance parameters and cannot be applied to the component; if T0=Tj0, the bypass diode 700 just meets the requirements of the component performance parameters and can be applied to the component; if T0>Tj0, the bypass diode 700 meets the requirements of the component performance parameters and has a safety margin, and can be applied to photovoltaic components with an open circuit voltage of Voc.

[0224] In this embodiment, by constructing the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship of the bypass diode 700, and converting them to obtain the voltage drop withstand voltage relationship, combined with the component performance parameters corresponding to the bypass diode 700 when the bypass diode 700 is actually connected in parallel with the component, it can be determined whether the bypass diode 700 can meet the requirements corresponding to the component performance parameters. The test process is simple and can quickly and accurately determine the safety and reliability of the bypass diode 700 when the component works for a long time.

[0225] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0226] In the description of this application, "first feature" or "second feature" may include one or more of the features.

[0227] In the description of the present application, “plurality” means two or more.

[0228] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0229] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for testing a bypass diode, characterized in that: include: Obtaining forward voltage drop values ​​of the bypass diode to be tested at different temperatures within a target temperature range, and determining a voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode; Obtaining the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range, and determining the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode; Based on the component performance parameters of the bypass diode, a test result of the bypass diode is determined according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

2. The bypass diode testing method according to claim 1, characterized in that: The component performance parameter includes a component opening voltage parameter of the bypass diode, and determining the test result of the bypass diode according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship includes: Determining a first operating temperature of the bypass diode based on the component opening voltage parameter and the junction temperature withstand voltage relationship; The first operating temperature is compared with an operating temperature threshold of the bypass diode, and a test result of the bypass diode is determined according to the comparison result.

3. The bypass diode testing method according to claim 2, characterized in that: The comparing the first operating temperature with the operating temperature threshold of the bypass diode and determining the test result of the bypass diode according to the comparison result includes: When the first operating temperature is greater than the operating temperature threshold, it is determined that the bypass diode test has passed.

4. The bypass diode testing method according to claim 1, characterized in that: The component performance parameter includes a component opening voltage parameter of the bypass diode and a diode voltage drop extreme value corresponding to the bypass diode at a diode junction temperature threshold, and determining a test result of the bypass diode according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship includes: Determining a first operating temperature of the bypass diode based on the component opening voltage parameter and the junction temperature withstand voltage relationship; Determining a second operating temperature of the bypass diode based on the diode voltage drop extreme value and the voltage drop junction temperature relationship; The first operating temperature and the second operating temperature are compared, and a test result of the bypass diode is determined according to the comparison result.

5. The bypass diode testing method according to claim 4, characterized in that: The comparing the first operating temperature with the second operating temperature and determining the test result of the bypass diode according to the comparison result includes: When the first operating temperature is greater than or equal to the second operating temperature, it is determined that the bypass diode test has passed.

6. The bypass diode testing method according to claim 1, characterized in that: The component performance parameter includes a component opening voltage parameter of the bypass diode and a diode voltage drop extreme value corresponding to the bypass diode at a diode junction temperature threshold, and determining a test result of the bypass diode according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship includes: Determining a voltage drop and withstand voltage relationship of the bypass diode based on the voltage drop and junction temperature relationship and the junction temperature and withstand voltage relationship; Determining a first target withstand voltage of the bypass diode based on the diode voltage drop extreme value and the voltage drop withstand voltage relationship; The first target withstand voltage is compared with the component start-up voltage parameter, and a test result of the bypass diode is determined according to the comparison result.

7. The bypass diode testing method according to claim 6, characterized in that: The comparing the first target withstand voltage with the component start-up voltage parameter and determining the test result of the bypass diode according to the comparison result includes: When the first target withstand voltage is greater than or equal to the component opening voltage parameter, it is determined that the bypass diode test has passed.

8. The bypass diode testing method according to any one of claims 1 to 7, characterized in that: The step of obtaining the forward voltage drop value of the bypass diode to be tested at different temperatures within the target temperature range includes: When the temperature of the bypass diode reaches the target temperature value within the target temperature range, a first pulse current is applied to the bypass diode to obtain a forward voltage drop value corresponding to the target temperature value, and the magnitude of the first pulse current is the component short-circuit current value corresponding to the bypass diode.

9. The bypass diode testing method according to any one of claims 1 to 7, characterized in that: The obtaining of the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range includes: When the temperature of the bypass diode reaches the target temperature value within the target temperature range, a reverse voltage is applied to the bypass diode, the current output current of the bypass diode is obtained and the reverse voltage is gradually increased, it is determined that the current output current is greater than or equal to the first current threshold, and the reverse withstand voltage extreme value corresponding to the target temperature value is obtained.

10. A bypass diode testing device, characterized in that: include: A first processing module is used to obtain the forward voltage drop value of the bypass diode to be tested at different temperatures within the target temperature range, and determine the voltage drop-junction-temperature relationship between the forward voltage drop and the junction temperature of the bypass diode; A second processing module is used to obtain the reverse withstand voltage extreme value of the bypass diode at different temperatures within the target temperature range, and determine the junction temperature withstand voltage relationship between the reverse withstand voltage and the junction temperature of the bypass diode; The third processing module is used to determine the test result of the bypass diode based on the component performance parameters of the bypass diode and according to at least one of the voltage drop junction temperature relationship and the junction temperature withstand voltage relationship.

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