Test system for grid-connected test of photovoltaic inverter

Abstract

The invention provides a test system for a photovoltaic inverter grid-connected test, and the system comprises a photovoltaic simulation equipment cabin which is connected with a to-be-tested photovoltaic inverter unit and is used for outputting a current to the photovoltaic inverter unit, and the photovoltaic inverter unit comprises one or more to-be-tested photovoltaic inverters; the low-voltage side multi-winding transformer unit comprises a transformer, and the low-voltage side of the transformer comprises at least two alternating-current windings of different voltage levels. The at least two alternating current windings are respectively connected with the photovoltaic inverter unit; and through interface switching of the at least two alternating current windings, the alternating current windings are matched with the photovoltaic inverters corresponding to the grid-connected voltage levels in the photovoltaic inverter unit so as to carry out grid-connected testing on the photovoltaic inverters. By outputting an adjustable photovoltaic simulation source, a conveniently accessed photovoltaic inverter and an integrally switched low-voltage side multi-winding transformer, the problems of large occupied area and low compatibility of a photovoltaic inverter test system are solved, and the efficiency of batch replacement and interface parameter matching of photovoltaic inverters is improved.

Description

Technical Field

[0001] This application relates to the field of power equipment detection. Specifically, it relates to a test system for grid-connected testing of photovoltaic inverters. Background Art

[0002] Before a photovoltaic inverter product is put into use, it needs to undergo a series of tests by specialized testing institutions such as electric power research institutes. Among them, grid-connected testing is a crucial link. However, there are various different grid-connected voltage levels for photovoltaic inverters. In response to this situation, the test systems built by testing institutions usually need to include multiple transformers with different turns ratios, which will lead to an increase in equipment investment costs and floor space. In addition, when a large number of photovoltaic inverters need to be tested for grid connection simultaneously, the disassembly, installation, and fixation of photovoltaic inverters all require a large amount of time and lack order.

[0003] The above information disclosed in the background art section is only used to enhance the understanding of the background of this application. Therefore, it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] To solve at least one of the above problems, this application proposes a test system for grid-connected testing of photovoltaic inverters.

[0005] According to the first aspect of this application, at least one embodiment of this application provides a test system for grid-connected testing of photovoltaic inverters, including: a photovoltaic simulation equipment cabin, connected to the photovoltaic inverter unit to be tested, for outputting current to the photovoltaic inverter unit, and the photovoltaic inverter unit includes one or more photovoltaic inverters to be tested; a low-voltage side multi-winding transformer unit includes a transformer, where: the low-voltage side of the transformer includes at least two AC windings with different voltage levels, and the high-voltage side is connected to the grid bus to access the grid, and the at least two AC windings are respectively connected to the photovoltaic inverter unit; through the interface switching of the at least two AC windings, it is matched with the photovoltaic inverter with the corresponding grid-connected voltage level in the photovoltaic inverter unit to perform grid-connected testing on the photovoltaic inverter.

[0006] For example, in some embodiments of this application, the photovoltaic simulation equipment cabin includes a photovoltaic simulation source, where: the photovoltaic simulation source is connected to the photovoltaic inverter and is used to output current to the photovoltaic inverter to perform grid-connected testing on the photovoltaic inverter.

[0007] For example, in some embodiments of this application, the photovoltaic simulation source outputs current in the form of a DC copper busbar.

[0008] For example, in some embodiments of the present application, the low-voltage side multi-winding transformer unit further includes: at least two circuit breakers, respectively connected to the at least two AC windings, and configured to perform interface switching according to the grid connection voltage level of the photovoltaic inverter so as to access the AC windings of the corresponding voltage level.

[0009] For example, in some embodiments of the present application, when the photovoltaic inverter determines the grid connection voltage level, the interface of the circuit breaker connected to the AC winding of the corresponding voltage level is closed.

[0010] For example, in some embodiments of the present application, each of the at least two circuit breakers includes a first interface and a second interface, wherein: one end of the first interface is connected to the photovoltaic inverter unit, and the other end is connected to the AC busbar of the corresponding voltage level; one end of the second interface is connected to the AC busbar of the corresponding voltage level, and the other end is connected to the corresponding AC winding of the transformer.

[0011] For example, in some embodiments of the present application, it further includes: a universal bracket for installing the photovoltaic inverter to perform grid connection tests on the photovoltaic inverter.

[0012] For example, in some embodiments of the present application, the universal bracket includes: a support frame for fixing the photovoltaic inverter; a ceiling disposed at the upper end of the support frame to cover the photovoltaic inverter; and a base disposed at the lower end of the support frame to fix the support frame.

[0013] For example, in some embodiments of the present application, the photovoltaic simulation source is disposed in a container, wherein: a hatch is provided on the first side wall of the container for maintaining and debugging the photovoltaic simulation source.

[0014] For example, in some embodiments of the present application, the photovoltaic inverter unit is disposed at the first side wall of the container.

[0015] The present application provides a test system for grid connection tests of a photovoltaic inverter, which solves the problems of large floor area and low compatibility of the photovoltaic inverter test system by means of an adjustable photovoltaic simulation source, a conveniently accessible photovoltaic inverter, and an integrally switched low-voltage side multi-winding transformer, and improves the efficiency of batch replacement of photovoltaic inverters and matching of interface parameters.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. Description of the Drawings

[0017] The above and other objectives, features, and advantages of the present application will become more apparent by describing its exemplary embodiments in detail with reference to the accompanying drawings. The accompanying drawings described below are only some embodiments of the present application and do not limit the present application.

[0018] Figure 1 Schematic diagram of a test system for grid - connection test of a photovoltaic inverter showing an exemplary embodiment;

[0019] Figure 2 Layout schematic diagram of a test system for grid - connection test of a photovoltaic inverter showing an exemplary embodiment;

[0020] Figure 3 Schematic diagram of a general bracket for a photovoltaic inverter showing an exemplary embodiment. Detailed implementation manners

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar parts, and thus their repeated description will be omitted.

[0022] The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will realize that the technical solutions of the present disclosure can be practiced without one or more of these specific details, or can be implemented in other ways, components, materials, devices, etc. In these cases, well - known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0023] The flowcharts shown in the accompanying drawings are only illustrative and do not necessarily include all the contents, operations, or steps, nor are they necessarily executed in the order described. For example, some operations or steps can be decomposed, and some operations or steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0024] In the description, claims and the above-mentioned drawings of this application, terms such as "first", "second", etc. are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0025] Those skilled in the art can understand that the drawings are only schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, so they cannot be used to limit the protection scope of this application.

[0026] Figure 1 Schematic diagram of a test system for grid-connected testing of a photovoltaic inverter, showing an exemplary embodiment.

[0027] As Figure 1 shown, the test system for grid-connected testing of a photovoltaic inverter includes a photovoltaic simulation equipment cabin 101 and a low-voltage side multi-winding transformer unit 103. The photovoltaic simulation equipment cabin 101 is connected to the low-voltage side multi-winding transformer unit 103 through a photovoltaic inverter unit 102 to achieve the connection of the test system.

[0028] According to the exemplary embodiment, the photovoltaic simulation equipment cabin 101 is connected to the photovoltaic inverter unit 102 to be tested and is used to output current to the photovoltaic inverter unit 102. The photovoltaic simulation equipment cabin 101 includes a plurality of photovoltaic simulation sources 1011 - 101N, and the photovoltaic simulation sources are connected to the photovoltaic inverter and are used to output current to the photovoltaic inverter for grid-connected testing of the photovoltaic inverter.

[0029] According to the exemplary embodiment, the output current of the photovoltaic simulation source can be flexibly adjusted. The photovoltaic simulation source outputs current in the form of a DC copper busbar, and a plurality of photovoltaic simulation sources 1011 - 101N are connected in parallel on the copper busbar according to test requirements to simulate the DC output of multiple string-type arrays.

[0030] According to the exemplary embodiment, the photovoltaic inverter unit 102 includes one or more photovoltaic inverters to be tested. A plurality of photovoltaic inverters 1021 - 102N can be installed in the photovoltaic inverter unit 102 at the same time to perform synchronous testing on multiple photovoltaic inverters and improve the efficiency of batch testing of photovoltaic inverters.

[0031] According to an exemplary embodiment, the low-voltage side multi-winding transformer unit 103 includes a transformer 1031, the low-voltage side of which includes at least two AC windings with different voltage levels, and the high-voltage side is connected to the grid bus to access the grid. Among them, at least two AC windings are respectively connected to the photovoltaic inverter unit. The low-voltage side multi-winding transformer unit integrates low-voltage AC windings of multiple voltage levels, and through the interface switching of at least two AC windings, it is matched with the photovoltaic inverter corresponding to the grid-connected voltage level in the photovoltaic inverter unit to perform grid-connected testing on the photovoltaic inverter.

[0032] According to an exemplary embodiment, the low-voltage side multi-winding transformer unit 103 further includes at least two circuit breakers 10321, 10322,..., 1032N. Each AC winding is respectively connected to a circuit breaker. The circuit breaker is used to perform interface switching according to the grid-connected voltage level of the photovoltaic inverter to access the AC winding of the corresponding voltage level. When the photovoltaic inverter determines the grid-connected voltage level, the interface of the circuit breaker connected to the AC winding of the corresponding grid-connected voltage level is closed.

[0033] According to some embodiments, each circuit breaker includes a first interface and a second interface to better disconnect the connected AC winding. Among them, one end of the first interface is connected to the photovoltaic inverter unit, and the other end is connected to the AC busbar of the corresponding voltage level. One end of the second interface is connected to the AC busbar of the corresponding voltage level, and the other end is connected to the corresponding AC winding of the transformer.

[0034] For example, as Figure 1 shown, the transformer of the low-voltage side multi-winding transformer unit integrates a 400V AC winding, a 540V AC winding, and an 800V AC winding; when the photovoltaic inverter needs to match the 400V AC grid, the interfaces of the circuit breakers connected to the 540V AC winding and the 800V AC winding are disconnected, and the interface of the circuit breaker connected to the 400V AC winding is closed. This application takes this as an example only, and the AC windings of different voltages integrated in the low-voltage side multi-winding transformer unit can be self-matched. This application takes this as an example only, but is not limited thereto.

[0035] This application provides a test system for grid-connected testing of photovoltaic inverters. By means of a photovoltaic simulation source with adjustable output, a conveniently accessible photovoltaic inverter, and an integrated switching low-voltage side multi-winding transformer, it solves the problems of large floor area and low compatibility of the photovoltaic inverter test system, and improves the efficiency of batch replacement of photovoltaic inverters and matching of interface parameters.

[0036] Figure 2 The layout diagram of the test system for grid-connected testing of photovoltaic inverters showing an exemplary embodiment is shown.

[0037] As Figure 2As shown, multiple photovoltaic simulation sources are arranged inside the container, that is, inside the photovoltaic simulation equipment compartment 101. Hatches 1041-104N are provided on the first side wall of the container for maintaining and debugging the photovoltaic simulation sources. The photovoltaic inverter unit 102 is arranged at the first side wall of the container to meet the requirements for maintenance and debugging between the photovoltaic simulation sources and the photovoltaic inverters.

[0038] According to the exemplary embodiment, the low-voltage side multi-winding transformer unit 103 is installed near the photovoltaic inverter 102, so that the layout of the entire test system is smooth and the wiring is convenient.

[0039] Figure 3 Schematic diagram of a general bracket for a photovoltaic inverter showing an exemplary embodiment.

[0040] For the portable installation of a photovoltaic inverter to be tested, the present application also proposes a general bracket. As Figure 3 shown, the test system includes a general bracket for installing a photovoltaic inverter to perform a grid connection test on the photovoltaic inverter. That is, the general bracket is arranged at the first side wall of the container. The general bracket includes a base 301, a support frame 302, and a ceiling 303. Among them, the base 301 is arranged at the lower end of the support frame 302 for fixing the support frame 302. The support frame 302 can be adjusted for installing and fixing photovoltaic inverters 102N of different sizes. The ceiling 303 is arranged at the upper end of the support frame 302 to cover the photovoltaic inverter 102N and shield the photovoltaic inverter from wind and rain.

[0041] The general bracket provided by the present application is installed on the ground and is applicable to photovoltaic inverters of various manufacturers, making the installation of photovoltaic inverter equipment convenient and stable.

[0042] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teachings of the content disclosed in the present application, these principles can be applied to many other embodiments.

[0043] In addition, it should be noted that the above-mentioned drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, rather than for limiting purposes. It is easy to understand that the processes shown in the above-mentioned drawings do not indicate or limit the time sequence of these processes. Additionally, it is also easy to understand that these processes can be executed, for example, synchronously or asynchronously in multiple modules.

[0044] The above specifically shows and describes the exemplary embodiments of the present application. It should be understood that the present application is not limited to the detailed structures, setting methods, or implementation methods described here; on the contrary, the present application intends to cover various modifications and equivalent settings included within the spirit and scope of the appended claims.

Claims

1. A test system for grid-connected testing of a photovoltaic inverter, characterized in that, Comprising: A photovoltaic simulation equipment cabin, connected to the photovoltaic inverter unit to be tested, for outputting current to the photovoltaic inverter unit, and the photovoltaic inverter unit includes one or more photovoltaic inverters to be tested; The low-voltage side multi-winding transformer unit includes a transformer, wherein: The low-voltage side of the transformer includes at least two AC windings with different voltage levels, and the high-voltage side is connected to the grid bus to access the grid, The at least two AC windings are respectively connected to the photovoltaic inverter unit; Through the interface switching of the at least two AC windings, it is matched with the photovoltaic inverter with the corresponding grid-connected voltage level in the photovoltaic inverter unit to perform grid-connected testing on the photovoltaic inverter.

2. The test system according to claim 1, wherein, The photovoltaic simulation equipment cabin includes a photovoltaic simulation source, wherein: The photovoltaic simulation source is connected to the photovoltaic inverter and is used for outputting current to the photovoltaic inverter to perform grid-connected testing on the photovoltaic inverter.

3. The test system according to claim 2, characterized in that, The photovoltaic simulation source outputs current in the form of a DC busbar.

4. The test system according to claim 1, wherein, The low-voltage side multi-winding transformer unit further includes: At least two circuit breakers, respectively connected to the at least two AC windings, for performing interface switching according to the grid-connected voltage level of the photovoltaic inverter to access the AC winding of the corresponding voltage level.

5. The test system according to claim 4, wherein When the photovoltaic inverter determines the grid-connected voltage level, the interface of the circuit breaker connected to the AC winding of the corresponding voltage level is closed.

6. The test system according to claim 4, wherein Each of the at least two circuit breakers includes a first interface and a second interface, wherein: One end of the first interface is connected to the photovoltaic inverter unit, and the other end is connected to the busbar of the corresponding voltage level; One end of the second interface is connected to the busbar of the corresponding voltage level, and the other end is connected to the corresponding AC winding of the transformer.

7. The test system according to claim 1, characterized in that, Further comprising: A universal bracket for installing the photovoltaic inverter to perform grid-connected testing on the photovoltaic inverter.

8. The test system according to claim 7, characterized in that The universal bracket includes: A support frame for fixing the photovoltaic inverter; A ceiling, arranged at the upper end of the support frame to cover the photovoltaic inverter; A base, arranged at the lower end of the support frame to fix the support frame.

9. The test system according to claim 2, characterized in that, The photovoltaic simulation source is arranged in a container, wherein: A cabin door is arranged on the first side wall of the container for maintaining and debugging the photovoltaic simulation source.

10. The test system according to claim 9, characterized in that, The photovoltaic inverter unit is arranged at the first side wall of the container.

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