A method for fault detection and identification of photovoltaic power generation components based on digital twin

A photovoltaic power generation and fault detection technology, applied in the field of solar photovoltaic power generation, can solve the problems of many photovoltaic panels and DC-DC converters, and achieve the effects of high efficiency, high flexibility and strong reliability

Active Publication Date: 2022-07-19
ANHUI SCI & TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the DC modular photovoltaic grid-connected power generation system, there are many photovoltaic panels and DC-DC converters used in the front stage, and it is not easy to identify and diagnose if a fault occurs

Method used

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  • A method for fault detection and identification of photovoltaic power generation components based on digital twin
  • A method for fault detection and identification of photovoltaic power generation components based on digital twin
  • A method for fault detection and identification of photovoltaic power generation components based on digital twin

Examples

Experimental program
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Effect test

example 1

[0090] Example 1: Calculation of fault characteristics when the fault type of solar cell module is i=1

[0091] The failure is due to the solar cell module being shaded (due to dust etc.). it causes failure of the panel (Light intensity is G ref =1000W / m 2 , the temperature is T ref = Under the condition of 25℃, when the maximum power is reached, the output current of the solar cell module) is in G ref (G ref =1000W / m 2 ) occurs when change (at this time changes are negligible). Therefore, the characteristic quantity y(t) in the physical entity of the photovoltaic power generation module to be detected in a steady state is obtained as:

[0092]

[0093] In formula (10), i o (t) is the output current of the DC-DC converter; D 3 , D 1 are the switching devices S 3 , S 1 The duty cycle of ; R is Figure 4 the resistance in the physical entity shown; is the light intensity G in the digital twin ref =1000W / m 2 , the temperature is T ref = Under the conditi...

example 2

[0098] Example 2: Calculation of fault characteristics when DC-DC converter fault type i=4

[0099] refer to image 3 As shown, if the switching device S 1 An open circuit fault occurs, and the fault event will cause the solar cell module output to open circuit. At this time, in this case, the residual vector γ(t)=z(t)-y(t), that is, equation (9) minus equation (10), the residual vector γ(t) is y(t) )=E[0,0,0,V oc ] T . The residual γ(t) is generated and analyzed to obtain the fault characteristic value f 4 and Similarly, the characteristic values ​​of other fault types of DC-DC converters listed in the table below can be obtained by calculation.

[0100] Table 2 DC-DC converter faults

[0101]

[0102]

[0103] table, I sc is the short-circuit current of the solar cell module; V oc is the open circuit voltage of the solar cell module; D 1 is the switching device S 1 The duty cycle of ; D 3 is the switching device S 3 duty cycle.

example 3

[0104] Example 3: Calculation of eigenvalues ​​when the fault type of electrical sensor is i=12

[0105] For measuring the inductor current i L (t) sensor considering gain drift Δc 12 (t) Drift and deviation of the measured value from the exact value Δe 12 (t) deviation. In the measured physical system, the failure of such a sensor can be modeled as:

[0106]

[0107] In formula (11), E is the unit matrix of the electrical sensor gain; ΔC(t) is the drift of the gain; i L (t) is the current flowing through the inductor L in the physical entity; v c (t) is the output voltage of the DC-DC converter in the physical entity; i pv (t) is the output current of the solar cell module in the physical entity, v pv (t) is the output voltage of the solar cell module in the physical entity; ΔE(t) is the deviation.

[0108] In this case, the residual γ(t)=z(t)-y(t), that is, γ(t)=[Δc 12 (t)i L (t)+Δe 12 (t),0,0,0] T . Therefore, the fault characteristic value f 12 =[1,0,0,0] ...

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Abstract

The invention discloses a method for detecting and identifying faults of photovoltaic power generation components based on digital twins. DC converter; construct a digital twin with the same physical structure as the photovoltaic power generation module to be tested, calculate and output the measured characteristic quantity z(t) of the photovoltaic power generation module in the digital twin; according to the characteristic quantity y(t), and measure The feature quantity z(t), calculate and output the residual vector γ(t); according to the residual vector γ(t), output the detection result; when there is a fault in the detection result, according to the residual vector γ(t), and the fault feature value f i , calculate and output L 2 Inner product; fault characteristic value f i By the residual vector γ(t) and the 2‑norm of the residual vector γ(t) ||γ(t)|| 2 Calculated; according to L 2 Inner product, output fault type. The method can detect whether a photovoltaic power generation module fails, and identify the type of failure. High reliability and strong practicability.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaic power generation, in particular to a fault detection and identification method for photovoltaic power generation components based on digital twins. Background technique [0002] As environmental issues receive increasing attention, the energy market is increasingly interested in photovoltaic power generation systems. The DC modular photovoltaic grid-connected power generation system is used by more and more people, refer to figure 1 As shown, each solar cell module in the system is connected with an independent DC-DC converter, and then the output terminals of these DC-DC converters are connected in series with the input terminal of a DC-AC converter , and the energy is input into the AC grid through the DC-AC converter. In the DC modular photovoltaic grid-connected power generation system, many photovoltaic panels and DC-DC converters are used in the front stage, and it is not easy t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/16H02S50/10
CPCH02S50/10Y02E10/50
Inventor 周小杰黄友锐国海徐善永权悦韩涛张帝胡福志
Owner ANHUI SCI & TECH UNIV
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