Direct-current combiner box, inverter, photovoltaic system and protection method

Abstract

The invention discloses a direct-current combiner box, an inverter, a photovoltaic system and a protection method. The combiner box comprises a switching device, a sampling circuit and a controller, wherein the switching device is connected in parallel between the positive input end and the negative input end; the sampling circuit is used for collecting at least one of input parameters and outputparameters of the combiner box; and the controller is used for controlling the switching device to be switched on when determining that a short circuit occurs between the output positive cable and theoutput negative cable or the output positive cable and the output negative cable are reversely connected according to the at least one parameter, and the switching device, the positive input end andthe negative input end form a closed loop. When the output end of the combiner box or a post-stage circuit of the output end is short-circuited, most of short-circuit current passes through the closedswitching device to form backflow, so that the current generated by the input end of the combiner box is reduced to be output from the output end of the combiner box, and overcurrent burnout of an output cable of the combiner box caused by overlarge output current of the combiner box is avoided. According to the scheme, the combiner box can be protected when positive and negative output cables are reversely connected.

Description

Technical field[0001]This application relates to the technical field of photovoltaic power generation, and in particular to a DC combiner box, an inverter, a photovoltaic system and a protection method.Background technique[0002]At present, as environmental pollution becomes more and more serious, the world is paying more and more attention to photovoltaic power generation.[0003]During photovoltaic power generation, due to the limited power generated by photovoltaic cells, it is generally necessary to connect multiple battery panel groups in series and parallel to input the combiner box.[0004]Seefigure 1 , The figure is a schematic diagram of a photovoltaic system provided by the prior art.[0005]At present, a plurality of battery panel groups are connected in series and parallel to the input end of the DC combiner box. For ease of introduction, the DC combiner box is referred to as the combiner box 100 in the following. The output terminal of the combiner box 100 is connected to the ...

AI Technical Summary

Problems solved by technology

[0008] At this time, when the output switches (K1-Kn) of each combiner box are closed, the output voltage of the combiner box will be quickly pulled to zero, and the output current will be the sum of the short-circuit current of each input battery string, and all the current will sink into a short-circuited branch circuit or a combiner box where the positive and negative cables are connected incorrectly, causing overcurrent burning of the cable or damage to the combiner box

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