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Method and device for positioning mismatched component in photovoltaic group string and photovoltaic system

A photovoltaic module and photovoltaic group technology, applied in the field of photovoltaic systems, can solve the problems of low efficiency and time-consuming positioning of mismatched components, and achieve the effect of improving efficiency

Active Publication Date: 2020-04-14
SUNGROW POWER SUPPLY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, for a photovoltaic string of a 1000V photovoltaic system, each photovoltaic string contains 20 modules, and for a photovoltaic string of a 1500V photovoltaic system, each photovoltaic string contains 35 modules. Each component is tested one by one. Obviously, the more components, the longer it takes, and the efficiency of mismatched component positioning is too low.

Method used

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  • Method and device for positioning mismatched component in photovoltaic group string and photovoltaic system
  • Method and device for positioning mismatched component in photovoltaic group string and photovoltaic system
  • Method and device for positioning mismatched component in photovoltaic group string and photovoltaic system

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Embodiment 1

[0048] see figure 1 , which is a flow chart of a method for locating mismatched components in a photovoltaic string provided by the present application.

[0049] The method for locating mismatched components in a photovoltaic string provided in this embodiment includes:

[0050] S101: Obtain all step voltage intervals on the IV curve of the faulty string;

[0051] Based on the fact that the IV curve of a normal photovoltaic module has a convex function feature, when there is a current mismatch problem in the module or string, a downward inflection point will appear on the IV curve, which reflects the concave function feature. Therefore, the IV curve can be used Bump detection to identify mismatch issues. The method for detecting the concavity and convexity of the curve is relatively mature, and will not be further elaborated here.

[0052] For details, please refer to figure 2 , which is a schematic diagram of the step voltage range of the mismatch component provided by t...

Embodiment 2

[0066] see image 3 , which is a flow chart of another method for locating mismatched components in a photovoltaic string provided by the present application.

[0067] Before obtaining all the step voltage intervals by using the IV curve of the faulty string, it also includes:

[0068] S301: Performing an IV scan on the photovoltaic string to obtain an IV curve.

[0069] S302: Identify a faulty string with current mismatch through the IV curve.

[0070] Specifically, the concavo-convex feature of the IV curve can be used for mismatch detection, and faulty strings with current mismatch can be identified. So far, only the entire faulty photovoltaic string has been identified, but the faulty component in the faulty string cannot be located. Therefore, it is necessary to locate the faulty component in the faulty string.

[0071] S303: Obtain all step voltage intervals by using the IV curve of the faulty string. All step voltage intervals on the IV curve are determined by the ...

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Abstract

The invention discloses a method and a device for positioning a mismatched component in a photovoltaic group string and a photovoltaic system. The method comprises the following steps: acquiring all step voltage intervals on an IV curve of a fault group string; sequentially controlling voltages of direct-current buses from high to low to enable the voltage of the fault group string to work in eachstep voltage interval, and carrying out infrared thermal imaging IR photographing on the fault group string in each step voltage interval; and obtaining the mismatch component corresponding to each step voltage interval according to an IR photographing result of each step voltage interval and the IV curve. According to the method, IR photographing is performed according to the step voltage interval instead of photographing each photovoltaic module in a mismatched group string one by one to judge whether mismatch occurs so that mismatched component positioning efficiency can be improved.

Description

technical field [0001] The present application relates to the technical field of photovoltaic power generation, and in particular to a positioning method, device and photovoltaic system for mismatched components in a photovoltaic string. Background technique [0002] At present, the inverter controls the DC bus voltage to detect the voltage-current V-I characteristics of the photovoltaic string (hereinafter referred to as IV scan), and then, through the IV curve fault diagnosis algorithm, the purpose of fault diagnosis of the photovoltaic string is realized. [0003] The faults of photovoltaic strings mainly include: current mismatch of components in photovoltaic strings, low short-circuit current, low open-circuit voltage, high series resistance, low parallel resistance, potential induced decay (PID for short), and voltage loss when multiple strings are connected in parallel. Matching issues. Among them, the current mismatch of components in the photovoltaic string is the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02S50/15H02S40/32
CPCH02S40/32H02S50/15Y02E10/50
Inventor 云平崔鑫徐君
Owner SUNGROW POWER SUPPLY CO LTD