A photovoltaic simulation device

Abstract

The application provides a photovoltaic simulation device. Since two poles of a direct-current power supply module are used as two poles of the photovoltaic simulation device, and the direct-current power supply module is used to simulate the volt-ampere characteristic of a photovoltaic string in a first quadrant, the photovoltaic simulation device can simulate the output of the photovoltaic string. In addition, since the switch module is turned on when the negative pole potential of the direct-current power supply module is greater than the positive pole potential of the direct-current power supply module, and the first preset resistor and the first preset inductor are used to simulate the equivalent resistance and the equivalent inductance of the diode branch respectively, the series branch formed by the switch module, the first preset resistor and the first preset inductor can be turned on when the two poles of the direct-current power supply module appear negative pressure due to the failure of external devices, like each bypass diode in the photovoltaic string, so that the photovoltaic simulation device provided by the application makes the negative pressure characteristic of the photovoltaic simulation device closer to the photovoltaic string.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrical testing, in particular to a photovoltaic simulation device. BACKGROUND

[0002] At present, the photovoltaic simulation device used for inverter testing includes a simulated photovoltaic DC power supply, which is mainly used for simulating the steady-state power characteristics of the forward voltage of a photovoltaic string and the steady-state power characteristics of the forward current, that is, the IV curve of the photovoltaic simulation device is consistent with the IV curve of the photovoltaic string in the first quadrant.

[0003] However, when the photovoltaic simulation device outputs a negative voltage due to the failure of external devices, the negative voltage characteristics thereof do not match the negative voltage characteristics of the photovoltaic string, thereby causing a large test deviation when the photovoltaic simulation device is used for inverter testing.

[0004] Therefore, how to make the negative voltage characteristics of the photovoltaic simulation device closer to the negative voltage characteristics of the photovoltaic string is a technical problem to be solved. SUMMARY

[0005] Therefore, the present application provides a photovoltaic simulation device to make the negative voltage characteristics of the photovoltaic simulation device closer to the negative voltage characteristics of the photovoltaic string.

[0006] To achieve the above-mentioned purpose, the embodiments of the present application provide the following technical solutions:

[0007] The present application provides a photovoltaic simulation device, comprising: a DC power supply module, a switch module, a first preset resistor and a first preset inductor; wherein:

[0008] The two poles of the DC power supply module are respectively used as the two poles of the photovoltaic simulation device, and the DC power supply module is used for simulating the voltage-current characteristics of the photovoltaic string in the first quadrant;

[0009] The input end of the switch module is connected with the negative pole of the DC power supply module, the output end of the switch module is connected with the positive pole of the DC power supply module, and the switch module is used for simulating the one-way conduction characteristics of the diode branch; the one-way conduction characteristics are the characteristics of the diode branch when the negative pole potential of the DC power supply module is greater than the positive pole potential of the DC power supply module;

[0010] The first preset resistor and the first preset inductor are both connected in series in the branch where the switch module is located, the first preset resistor is used for simulating the equivalent resistance of the diode branch, and the first preset inductor is used for simulating the equivalent inductance of the diode branch.

[0011] Optionally, the resistance value of the first preset resistor is equal to the resistance value of the equivalent resistance of the bypass diode branch of the photovoltaic string.

[0012] The first preset inductance is equal to the inductance of the bypass diode branch.

[0013] The bypass diode branch is formed by the bypass diodes in the photovoltaic string and is parallelly connected between the two poles of each photovoltaic sub-string in each photovoltaic module.

[0014] Optionally, the direct current power supply module comprises a direct current constant voltage power supply and a second preset resistor; wherein:

[0015] The direct current constant voltage power supply and the second preset resistor are connected in series, the positive pole of the series branch is the positive pole of the direct current power supply module, and the negative pole of the series branch is the negative pole of the direct current power supply module.

[0016] The no-load voltage of the direct current constant voltage power supply is equal to the open circuit voltage of the photovoltaic string, and the resistance value of the second preset resistor is equal to the resistance value of the equivalent output resistance of the photovoltaic string under the corresponding output requirement.

[0017] Optionally, in the direct current constant voltage power supply, a first main structure and a first preset capacitor are included; wherein:

[0018] The first preset capacitor is connected in parallel between the two poles of the first main structure.

[0019] Optionally, the output requirement includes any one of the following: low-voltage output, high-voltage output, and maximum current and maximum voltage output, respectively.

[0020] Optionally, the direct current power supply module comprises an analog photovoltaic direct current power supply and a third preset resistor; wherein:

[0021] The analog photovoltaic direct current power supply and the third preset resistor are connected in series, the positive pole of the series branch is the positive pole of the direct current power supply module, and the negative pole of the series branch is the negative pole of the direct current power supply module.

[0022] The analog photovoltaic direct current power supply is used to simulate the voltage-current characteristic of the photovoltaic string in the first quadrant, and the resistance value of the third preset resistor is equal to the equivalent output resistance of the photovoltaic string under the corresponding output requirement.

[0023] Optionally, in the analog photovoltaic direct current power supply, a second main structure and a second preset capacitor are included; wherein:

[0024] The second preset capacitor is connected in parallel between the two poles of the second main structure.

[0025] Optionally, the output requirement includes any one of the following: low-voltage output, high-voltage output, and maximum current and maximum voltage output, respectively.

[0026] Optionally, if the direct current power module comprises the second preset resistance or the third preset resistance, then:

[0027] The first preset inductance is converted into a second preset inductance; the second preset inductance is an inductance on a total branch formed by a branch in which the switch module is located and a branch in which the direct current power module is located;

[0028] The inductance value of the second preset inductance is equal to the inductance value of the first preset inductance.

[0029] Optionally, the switch module comprises a power diode or a switch tube.

[0030] As can be seen from the above technical solution, the present application provides a photovoltaic simulation device. In the photovoltaic simulation device, since the two poles of the direct current power module are used as the two poles of the photovoltaic simulation device, and the direct current power module is used to simulate the voltage-current characteristic of the photovoltaic module string in the first quadrant, the photovoltaic simulation device can simulate the output of the photovoltaic module string. Further, since the switch module is turned on when the negative pole potential of the direct current power module is greater than the positive pole potential of the direct current power module in the diode branch, and the first preset resistance and the first preset inductance are used to simulate the equivalent resistance and the equivalent inductance of the diode branch, respectively, the series branch formed by the switch module, the first preset resistance and the first preset inductance can be turned on when the two poles of the direct current power module appear negative pressure due to the failure of external devices, like each bypass diode in the photovoltaic module string, so that the photovoltaic simulation device provided by the present application makes the negative pressure characteristic of the photovoltaic simulation device closer to the photovoltaic module string. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without any creative effort.

[0032] Figure 1 The structure of an embodiment of the photovoltaic simulation device provided by the present application is shown in the schematic view;

[0033] Figure 2 The structure of an example of the photovoltaic module string is shown in the schematic view;

[0034] Figure 3 The structure of another embodiment of the photovoltaic simulation device provided by the present application is shown in the schematic view;

[0035] Figure 4 The IV curve of the photovoltaic module string is shown in the schematic view;

[0036] Figure 5 A schematic structural view of another embodiment of the photovoltaic simulation device provided in this application;

[0037] Figure 6 This is a schematic diagram simulating the structure of a photovoltaic DC power supply 12;

[0038] Figure 7 and Figure 8 These are schematic structural views of two more embodiments of the photovoltaic simulation device provided in this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0040] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] To make the negative voltage characteristics of the photovoltaic simulation device more closely resemble those of a photovoltaic string, this application provides a photovoltaic simulation device, the specific structure of which is as follows: Figure 1 (Taking power diode D1 as an example to illustrate the switching module 20) As shown, it specifically includes: DC power supply module 10, switching module 20, first preset resistor R1, and first preset inductor L1; the connection relationships between the components and the functions of each component are described in detail below:

[0042] The two poles of the DC power module 10 serve as the two poles of the photovoltaic simulation device. The DC power module 10 is used to simulate the volt-ampere characteristics of the photovoltaic string in the first quadrant.

[0043] The input terminal of the switch module 20 is connected to the negative terminal of the DC power supply module 10, and the output terminal of the switch module 20 is connected to the positive terminal of the DC power supply module 10. The switch module 20 is used to simulate the unidirectional conduction characteristic of the diode branch. The unidirectional conduction characteristic is the characteristic of the diode branch conducting when the negative terminal potential of the DC power supply module is greater than the positive terminal potential of the DC power supply module.

[0044] The first preset resistor R1 and the first preset inductor L1 are both connected in series in the branch where the switch module 20 is located. The first preset resistor R1 is used to simulate the equivalent resistance of the diode branch, and the first preset inductor L1 is used to simulate the equivalent inductance of the diode branch.

[0045] Since the two poles of the DC power module 10 serve as the two poles of the photovoltaic simulation device, and are used to simulate the volt-ampere characteristics of the photovoltaic string in the first quadrant, the photovoltaic simulation device can simulate the output of the photovoltaic string. Furthermore, since the switch module 20 conducts when the diode branch is at a voltage greater than the positive voltage of the DC power module, and the first preset resistor R1 and the first preset inductor L1 are used to simulate the equivalent resistance and equivalent inductance of the diode branch, the series branch formed by the switch module 20, the first preset resistor R1, and the first preset inductor L1 can conduct when a negative voltage occurs at the two poles of the DC power module 10 due to a fault in an external device, just like the bypass diodes in the photovoltaic string. Thus, the photovoltaic simulation device provided in this application makes the negative voltage characteristics of the photovoltaic simulation device closer to those of the photovoltaic string. Consequently, when using the photovoltaic simulation device to test the inverter, the test deviation can be further reduced.

[0046] Optionally, the switching module 20 can be a power diode D1, such as... Figure 1 As shown, the anode of power diode D1 serves as the input terminal of switch module 20, and the cathode of power diode D1 serves as the output terminal of switch module 20; alternatively, a switching transistor can be used, in which case the input terminal of the switching transistor serves as the input terminal of switch module 20, and the output terminal of the switching transistor serves as the output terminal of switch module 20; no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0047] Optionally, the switching transistor can be a MOSFET or an IGBT; in practical applications, it may be any of the above, but no specific limitation is made here. It may be determined according to the specific circumstances, and all of them are within the protection scope of this application.

[0048] It should be noted that when selecting the power diode D1, a diode with a maximum surge current greater than the maximum surge current of the bypass diode branch of the photovoltaic string should be selected to prevent frequent failures of the photovoltaic simulation device and improve the working reliability of the photovoltaic simulation device.

[0049] Among them, the bypass diode branch is the branch formed by the bypass diodes connected in parallel between the two poles of each photovoltaic sub-string in each photovoltaic module in the photovoltaic string; the following is an example. Figure 2 The bypass diode branch is explained using the photovoltaic string shown as an example, as detailed below:

[0050] exist Figure 2 The photovoltaic string shown includes four photovoltaic modules 01. Among the four photovoltaic modules 01, every two photovoltaic modules 01 are connected in series to form two series branches. The two series branches are then connected in parallel to form the photovoltaic string. Each photovoltaic module includes three photovoltaic sub-strings 02. A bypass diode D2 is connected in anti-parallel between the two poles of each photovoltaic sub-string 02. Therefore, all the bypass diodes D2 are connected to form a bypass diode branch.

[0051] Another embodiment of this application provides another implementation of the photovoltaic simulation device. The structure of this implementation is basically the same as the above-described implementation, except that:

[0052] The resistance of the first preset resistor R1 is equal to the equivalent resistance of the bypass diode branch of the photovoltaic string; the inductance of the first preset inductor L1 is equal to the equivalent inductance of the bypass diode branch.

[0053] It should be noted that the bypass diode branch of the photovoltaic string has been described in detail in the above embodiments, and will not be repeated here. Please refer to the relevant descriptions in the above embodiments.

[0054] In this embodiment, by adding the above-mentioned limitation to the above-described implementation of the photovoltaic simulation device, the negative voltage characteristics of this implementation of the photovoltaic simulation device are made closer to the negative voltage characteristics of the photovoltaic string, thereby further reducing the test deviation when using this implementation to test the inverter.

[0055] The following is based on Figure 2 Taking the photovoltaic string shown as an example, the process of determining the resistance value of the first preset resistor R1 and the inductance value of the first preset inductor L1 is explained.

[0056] The process of determining the resistance value of the first preset resistor R1 is as follows:

[0057] First, determine the equivalent resistance of each bypass diode D2, which is the resistance of the bypass diode when it is conducting. To determine the equivalent resistance of each bypass diode D2, first find the nominal voltage Vf and nominal current If of the bypass diode D2 from the datasheet. Then, determine the equivalent resistance of each bypass diode D2 using the formula rf = Vf / If; where rf is the equivalent resistance of the bypass diode D2.

[0058] Next, determine the value of the first preset resistor R1. The specific process is as follows: Determine the value of the first preset resistor R1 according to the formula R1 = number of photovoltaic modules O1 in series in each series branch * number of bypass diodes D2 in each photovoltaic module * rf / number of series branches connected in parallel in each photovoltaic string.

[0059] The process of determining the resistance value of the first preset inductor L1 is as follows:

[0060] First, the total equivalent inductance lf of the cable required to achieve the bypass diode D2 connection in each photovoltaic module 01 is obtained through experiments. Then, according to the formula L1 = number of photovoltaic modules 01 in series in each series branch * lf / number of series branches connected in parallel in each photovoltaic string.

[0061] Another embodiment of this application provides a specific implementation of the DC power supply module 10, the specific structure of which is as follows: Figure 3 (exist Figure 1 As shown in the diagram (based on the existing structure), it specifically includes: a DC constant voltage power supply 11 and a second preset resistor R2; their connection relationship is as follows:

[0062] The DC constant voltage power supply 11 and the second preset resistor R2 are connected in series. The positive terminal of the series branch serves as the positive terminal of the DC power supply module 10, and the negative terminal of the series branch serves as the negative terminal of the DC power supply module 10.

[0063] Among them, the no-load voltage of the DC constant voltage power supply 11 is equal to the open-circuit voltage of the photovoltaic string, and the resistance value of the second preset resistor R2 is equal to the resistance value of the equivalent output resistance of the photovoltaic string under the corresponding output requirements.

[0064] It should be noted that the DC constant voltage power supply 11 is a relatively mature power supply device, and will not be described in detail here; however, the DC constant voltage power supply 11 includes a first main structure and a first preset capacitor connected in parallel between the two poles of the first main structure; under normal circumstances, the value of the first preset capacitor is relatively large, and this value is much larger than the capacitance value of the actual port capacitance between the two poles of the photovoltaic string, so as to stabilize the output voltage of the DC constant voltage power supply 11, that is, stabilize the output voltage of the photovoltaic simulation device.

[0065] Since the value of the first preset capacitor is usually large, under normal circumstances, when the output voltage of the DC constant voltage power supply 11 changes transiently due to an external device failure, the inrush current generated on the two poles of the DC constant voltage power supply 11 is much greater than the inrush current generated on the two poles of the photovoltaic string. However, in this embodiment, since the DC constant voltage power supply 11 is connected in series with the second preset resistor R2, the inrush current generated on the two poles of the DC constant voltage power supply 11 will flow through the second preset resistor R2. Therefore, the inrush current generated on the two poles of the DC constant voltage power supply 11 can be reduced, thereby making the transient characteristics of the photovoltaic simulation device closer to the transient characteristics of the photovoltaic string.

[0066] Furthermore, since the resistance of the second preset resistor R2 is equal to the equivalent output resistance of the photovoltaic string under the corresponding output requirements, the inrush current generated across the DC constant voltage power supply 11 is closer to the inrush current generated across the photovoltaic string. Therefore, the transient characteristics of the photovoltaic simulation device are made even closer to the transient characteristics of the photovoltaic string.

[0067] The output requirement can be low voltage output, high voltage output, or output at maximum current and maximum voltage respectively; no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0068] The process of determining the resistance value of the second preset resistor R2 is explained below:

[0069] like Figure 4 As shown, the IV curve of the photovoltaic string is divided into a low-voltage section, a high-voltage section, and a negative-voltage section; among them, the negative-voltage section is independent of the second preset resistor R2, and will be ignored in the following explanation.

[0070] When the output requirement is low voltage output, corresponding to the low voltage segment, the resistance value of the second preset resistor R2 is: R2 = Vmp / (Isc - Imp); when the output requirement is high voltage output, corresponding to the high voltage segment, the resistance value of the second preset resistor R2 is: R2 = (Voc - Vmp) / Imp; when the output requirement is to output at maximum current and maximum voltage respectively, the resistance value of the second preset resistor R2 is: R2 = Voc / Isc.

[0071] Where Isc is the short-circuit current, Voc is the open-circuit voltage, Imp is the MPPT (Maximum PowerPoint Tracking) current, and Vmp is the MPPT voltage.

[0072] This embodiment also provides another specific implementation of the DC power supply module 10, the specific structure of which is as follows: Figure 5 (exist Figure 1As shown in the demonstration (based on the above), it specifically includes: a simulated photovoltaic DC power supply 12 and a third preset resistor R3; their connection relationship is as follows:

[0073] The simulated photovoltaic DC power supply 12 and the third preset resistor R3 are connected in series. The positive terminal of the series branch serves as the positive terminal of the DC power supply module 10, and the negative terminal of the series branch serves as the negative terminal of the DC power supply module 10.

[0074] The simulated photovoltaic DC power supply 12 is used to simulate the volt-ampere characteristics of the photovoltaic string in the first quadrant, that is, the IV curve of the simulated photovoltaic DC power supply 12 is consistent with the IV curve of the photovoltaic string in the first quadrant; the resistance value of the third preset resistor is equal to the equivalent output resistance of the photovoltaic string under the corresponding output requirements.

[0075] It should be noted that the simulated photovoltaic DC power supply 12 is a relatively mature power supply device, and will not be described in detail here; however, the simulated photovoltaic DC power supply 12 includes a second main structure 01 and a second preset capacitor Cy connected in parallel between the two poles of the second main structure 01, which can be found in [reference needed]. Figure 6 Normally, the value of the second preset capacitor Cy is relatively large, and this value is much larger than the actual port capacitance between the two poles of the photovoltaic string, so as to stabilize the output voltage of the DC constant voltage power supply 11, that is, to stabilize the output voltage of the photovoltaic simulation device.

[0076] Since the value of the second preset capacitor is usually large, under normal circumstances, when the output voltage of the simulated photovoltaic DC power supply 12 changes transiently due to an external device failure, the inrush current generated on the two poles of the simulated photovoltaic DC power supply 12 is much greater than the inrush current generated on the two poles of the photovoltaic string. However, in this embodiment, since the simulated photovoltaic DC power supply 12 is connected in series with the third preset resistor R3, the inrush current generated on the two poles of the simulated photovoltaic DC power supply 12 will flow through the third preset resistor R3. Therefore, the inrush current generated on the two poles of the simulated photovoltaic DC power supply 12 can be reduced, thereby making the transient characteristics of the photovoltaic simulation device closer to the transient characteristics of the photovoltaic string.

[0077] In addition, since the resistance of the third preset resistor R3 is equal to the equivalent output resistance of the photovoltaic string under the corresponding output requirements, the inrush current generated on the two poles of the simulated photovoltaic DC power supply 12 is closer to the inrush current generated on the two poles of the photovoltaic string. Therefore, the transient characteristics of the photovoltaic simulation device are closer to the transient characteristics of the photovoltaic string.

[0078] The output requirement can be low voltage output, high voltage output, or output at maximum current and maximum voltage respectively; no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0079] It should be noted that the process of determining the resistance value of the third preset resistor R3 is the same as the process of determining the resistance value of the second preset resistor R2, and will not be repeated here. Please refer to the above description.

[0080] In the two embodiments of the DC power module 10 described above, the second embodiment of the DC power module 10 is closer to the output of the photovoltaic string, but it has a higher cost. Although the first embodiment of the DC power module 10 is not as close to the output of the photovoltaic string as the second embodiment, it has a lower cost. Therefore, the two embodiments of the DC power module 10 can be selected according to the actual situation, and no specific limitation is made here.

[0081] Another embodiment of this application provides yet another implementation of a photovoltaic simulation device, the specific structure of which can be found in [reference needed]. Figure 7 ( Figure 7 Only Figure 3 Based on the presentation) or Figure 8 ( Figure 8 Only Figure 3 This implementation method is based on the demonstration (and is similar to...). Figure 3 or Figure 5 The photovoltaic simulation devices shown are largely the same, with the following differences:

[0082] In this embodiment, the first preset inductor L1 is converted into the second preset inductor L2; wherein, the second preset inductor L2 is the inductance on the main branch formed by the convergence of the branch where the switch module 20 is located and the branch where the DC power supply module 10 is located; and, the inductance value of the second preset inductor L2 is equal to the inductance value of the first preset inductor L1.

[0083] Since there is a second preset resistor R2 or a third preset resistor R3 in the DC power module 10, the influence of the second preset inductor L2 on the branch where the DC power module 10 is located is almost negligible. Therefore, the first preset inductor L1 can be converted into the second preset inductor L2.

[0084] The connection method of the second preset inductor L2 is described in detail below:

[0085] like Figure 7 As shown, the first connection method for the second preset inductor L2 is:

[0086] One end of the second preset inductor L2 is connected to the connection point between the output terminal of the branch where the switch module 20 is located and the positive terminal of the branch where the DC power supply module 10 is located. The other end of the second preset inductor L2 serves as the positive terminal of the photovoltaic simulation device.

[0087] like Figure 8 As shown, the second connection method for the second preset inductor L2 is:

[0088] One end of the second preset inductor L2 is connected to the connection point between the input terminal of the branch where the switch module 20 is located and the negative terminal of the branch where the DC power supply module 10 is located. The other end of the second preset inductor L2 serves as the negative terminal of the photovoltaic simulation device.

[0089] The above are only two connection methods for the second preset inductor L2. No specific determination is made here. It can be determined according to the specific situation. All of them are within the protection scope of this application.

[0090] The features described above in the disclosed embodiments can be substituted or combined with each other, enabling those skilled in the art to implement or use this application. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A photovoltaic simulation device, characterized in that, include: DC power supply module, switching module, first preset resistor and first preset inductor; wherein: The two poles of the DC power module serve as the two poles of the photovoltaic simulation device, and the DC power module is used to simulate the volt-ampere characteristics of the photovoltaic string in the first quadrant. The input terminal of the switching module is connected to the negative terminal of the DC power supply module, and the output terminal of the switching module is connected to the positive terminal of the DC power supply module. The switching module is used to simulate the unidirectional conduction characteristic of a diode branch. The unidirectional conduction characteristic is the characteristic that the diode branch conducts when the negative terminal potential of the DC power supply module is greater than the positive terminal potential of the DC power supply module. The first preset resistor and the first preset inductor are both connected in series in the branch where the switching module is located. The first preset resistor is used to simulate the equivalent resistance of the diode branch, and the first preset inductor is used to simulate the equivalent inductance of the diode branch. Wherein, the resistance value of the first preset resistor is equal to the resistance value of the equivalent resistance of the bypass diode branch of the photovoltaic string. The inductance value of the first preset inductor is equal to the inductance value of the equivalent inductance of the bypass diode branch; The bypass diode branch is the branch formed by the bypass diodes connected in parallel between the two poles of each photovoltaic sub-string in each photovoltaic module in the photovoltaic string.

2. The photovoltaic simulation device according to claim 1, characterized in that, The DC power supply module includes: a DC constant voltage power supply and a second preset resistor; wherein: The DC constant voltage power supply is connected in series with the second preset resistor, and the positive terminal of the series branch serves as the positive terminal of the DC power supply module, while the negative terminal of the series branch serves as the negative terminal of the DC power supply module. The open-circuit voltage of the DC constant voltage power supply is equal to the open-circuit voltage of the photovoltaic string, and the resistance value of the second preset resistor is equal to the equivalent output resistance value of the photovoltaic string under the corresponding output requirements.

3. The photovoltaic simulation device according to claim 2, characterized in that, The DC constant voltage power supply includes: a first main structure and a first preset capacitor; wherein: The first preset capacitor is connected in parallel between the two poles of the first main structure.

4. The photovoltaic simulation device according to claim 2, characterized in that, The output requirements include any of the following: low voltage output, high voltage output, and output at maximum current and maximum voltage, respectively.

5. The photovoltaic simulation device according to claim 1, characterized in that, The DC power supply module includes: an analog photovoltaic DC power supply and a third preset resistor; wherein: The simulated photovoltaic DC power supply is connected in series with the third preset resistor, with the positive terminal of the series branch serving as the positive terminal of the DC power supply module and the negative terminal of the series branch serving as the negative terminal of the DC power supply module. The simulated photovoltaic DC power supply is used to simulate the volt-ampere characteristics of the photovoltaic string in the first quadrant, and the resistance value of the third preset resistor is equal to the equivalent output resistance of the photovoltaic string under the corresponding output requirements.

6. The photovoltaic simulation device according to claim 5, characterized in that, The simulated photovoltaic DC power supply includes: a second main structure and a second preset capacitor; wherein: The second preset capacitor is connected in parallel between the two poles of the second main structure.

7. The photovoltaic simulation device according to claim 5, characterized in that, The output requirements include any of the following: low voltage output, high voltage output, and output at maximum current and maximum voltage, respectively.

8. The photovoltaic simulation device according to any one of claims 1 to 7, characterized in that, If the DC power supply module includes a second preset resistor or a third preset resistor, then: The first preset inductor is converted into a second preset inductor; the second preset inductor is the inductor on the main branch formed by the convergence of the branch where the switching module is located and the branch where the DC power module is located. The inductance value of the second preset inductor is equal to the inductance value of the first preset inductor.

9. The photovoltaic simulation device according to any one of claims 1 to 7, characterized in that, The switching module includes a power diode or a switching transistor.

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