An online IV curve test device and test method for a photovoltaic power generation system

Abstract

The invention discloses a photovoltaic power generation system online IV curve test device and a test method. The online IV curve test device comprises a temperature acquisition system, a solar irradiance gauge, a multi-channel photovoltaic assembly IV tester, an industrial control computer, a switch, a host computer and a switching case. According to the online IV curve test device, a relay with relatively low cost and having no arc discharge is employed to switch photovoltaic assemblies, IV curves of the assemblies are respectively tested through rapid scanning, accurate volt-ampere characteristics of the photovoltaic assemblies are acquired, and the online IV curve test device satisfies online IV curve tests on all channel assembly strings through cascade networking at present. Through the method, after switching one assembly at each time, an output voltage of the residual assembly string is guaranteed to be greater than the lowest input work voltage of an inverter, and a cell input power is further guaranteed to be greater than a normal start power of the inverter. The whole test period of rapid assembly switching, rapid IV curve scanning test and rapid switching recovery is controlled to be quite short, the online IV curve test function is realized.

Description

Technical field [0001] The invention relates to the field of photovoltaic power generation system testing, in particular to an online IV curve testing device and a testing method for photovoltaic power generation systems. Background technique [0002] Photovoltaic power generation systems usually consist of photovoltaic modules, strings, combiner boxes, inverters and other equipment. According to the difference in the open circuit voltage of a single photovoltaic module and the input voltage range of the photovoltaic grid-connected inverter, the photovoltaic modules connected in series to each string The number of components is different, usually 8-12 pieces or more. In the construction of the power station, multiple photovoltaic strings are connected to a combiner box for confluence and then connected to the inverter. The inverter will control the output power of the photovoltaic string to the maximum through the maximum power point tracking circuit to achieve the power generati...

AI Technical Summary

Problems solved by technology

This patent realizes the online test function, but it cannot scan the entire IV curve

[0008] At present, the IV curve test of the photovoltaic power generation system must disconnect the back-stage inverter, and then dismantle the photovoltaic modules one by one to measure the IV curve one by one. The test workload is huge and the power generation revenue during the test is sacrificed; Data collected at a fixed point in the IV curve by a voltage sensor or a current sensor cannot truly reflect the actual power generation performance of the module

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