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A method and system for detecting the current-voltage curve of a photovoltaic string

A current-voltage, photovoltaic group technology, applied in the field of photovoltaic power generation, can solve problems such as low detection efficiency, poor reliability, and increased hardware costs

Active Publication Date: 2018-03-27
HUAWEI DIGITAL POWER TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this will inevitably increase the hardware cost, and the detection efficiency is low and the reliability is poor

Method used

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  • A method and system for detecting the current-voltage curve of a photovoltaic string
  • A method and system for detecting the current-voltage curve of a photovoltaic string
  • A method and system for detecting the current-voltage curve of a photovoltaic string

Examples

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Embodiment 1

[0041] An embodiment of the present invention provides a schematic diagram of a photovoltaic power generation system, such as figure 1 As shown, it includes: n photovoltaic inverters, photovoltaic strings and power grid. Each photovoltaic inverter is connected to at least two photovoltaic strings, and each photovoltaic inverter is connected to the grid.

[0042] A photovoltaic inverter is a device that completes the inversion process of converting DC power into AC power.

[0043] A photovoltaic string includes a plurality of photovoltaic modules connected in series or / and in parallel. Photovoltaic modules, also known as solar panels, are the core part of photovoltaic power generation systems. They convert solar energy into electrical energy, provide DC output, and transmit it to batteries for storage, or drive loads to work. A single solar cell cannot be directly used as a power source, and several single cells need to be connected in series or / and in parallel and tightly pa...

Embodiment 2

[0064]An embodiment of the present invention provides a method for detecting the current-voltage curve of a photovoltaic string, which is applied to a photovoltaic inverter, and the first photovoltaic string and the second photovoltaic string of the photovoltaic inverter, such as image 3 shown, including:

[0065] Step 201. Control the input voltage of the first photovoltaic string to a first voltage, and obtain a first current of the first photovoltaic string.

[0066] Specifically, the photovoltaic inverter can control the input voltage of the first photovoltaic string to a fixed reference voltage value, and the first voltage is a fixed reference voltage value; or, control the input voltage of the first photovoltaic string to be within a preset range The first voltage is any voltage fluctuation value within a preset range. The first current of the first photovoltaic string is a current corresponding to the first voltage.

[0067] It should be noted that the input voltage ...

Embodiment 3

[0107] An embodiment of the present invention provides a photovoltaic inverter 40, such as Figure 9 shown, including:

[0108] a control unit 401, configured to control the input voltage of the first photovoltaic string to a first voltage;

[0109] An acquisition unit 402, configured to acquire a first current of the first photovoltaic string, where the first current of the first photovoltaic string is a current corresponding to the first voltage;

[0110] The adjustment unit 403 is configured to adjust the voltage of the second photovoltaic string from the open circuit voltage to the short circuit voltage, and during the process of detecting the current-voltage IV curve of the second photovoltaic string, the acquisition unit 402 is also configured to acquire The maximum current of the first photovoltaic string and the minimum current of the first photovoltaic string;

[0111] The processing unit 404 is configured to: under the condition that the second photovoltaic string is...

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Abstract

The application provides a method and system for detecting a current-voltage curve of a photovoltaic string, relating to the field of photovoltaic power generation. On the condition whether an IV curve of the photovoltaic string is affected by illumination change, hardware devices required to provide can be effectively reduced, and the detection reliability and the detection efficiency are improved to a certain extent. The method comprises the following steps of controlling an input voltage of the first photovoltaic string to a first voltage, and acquiring a first current of the first photovoltaic string; regulating the voltage of a second photovoltaic string to a short-circuit voltage from an open-circuit voltage; acquiring the maximum current of the first photovoltaic string and the minimum current of the first photovoltaic string during detection process of the IV curve of the second photovoltaic string; and determining no change of illumination to the first photovoltaic string when the second photovoltaic string and the first photovoltaic string are in the same light environment, and thereby determining that the IV curve of the second photovoltaic string is not affected by the illumination change.

Description

technical field [0001] The present invention relates to the field of photovoltaic power generation, in particular to a method and system for detecting a current-voltage curve of a photovoltaic string. Background technique [0002] Photovoltaic power generation system is a power generation system that directly converts solar energy into electrical energy using photovoltaic modules (English full name: Solar Cell module), including photovoltaic strings, batteries, controllers and photovoltaic inverters. A photovoltaic string includes a plurality of photovoltaic modules connected in series or / and in parallel, and a photovoltaic module is the smallest indivisible photovoltaic battery combination device that can provide direct current output alone. Then, the fundamental factor that determines the power generation capacity of the photovoltaic power generation system is the current and voltage IV output characteristics of the photovoltaic string. [0003] At present, the IV tester ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02S50/10
CPCH02S50/10Y02E10/50
Inventor 尹凯缪金松孟元东
Owner HUAWEI DIGITAL POWER TECH CO LTD