Photovoltaic power generating assembly fault detection and identification method based on digital twinning

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 reliability and high flexibility

Active Publication Date: 2021-10-08
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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  • Photovoltaic power generating assembly fault detection and identification method based on digital twinning
  • Photovoltaic power generating assembly fault detection and identification method based on digital twinning
  • Photovoltaic power generating assembly fault detection and identification method based on digital twinning

Examples

Experimental program
Comparison scheme
Effect test

example 1

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

[0091] This failure is due to the solar cell module being blocked (due to factors such as dust). it causes failure of the battery board's (light intensity is G ref =1000W / m 2 , the temperature is T ref = In the case of 25°C, when the maximum power is reached, the output current of the solar cell module) is in G ref (G ref =1000W / m 2 ) occurred in the case of changes (at this time changes are negligible). Therefore, it is concluded that the characteristic quantity y(t) in the physical entity of the photovoltaic power generation module to be detected in the steady state is:

[0092]

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

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 output of the solar cell module to open-circuit. At this time, in this case, the residual vector γ(t)=z(t)-y(t), that is, the formula (9) minus the formula (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 eigenvalues ​​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 duty cycle; D 3 is the switching device S 3 duty cycle.

example 3

[0104] Example 3: Eigenvalue calculation when the electrical sensor fault type is i=12

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

[0106]

[0107] In the formula (11), E is the identity 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 DC-DC converter output voltage 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 eigenvalue f 12 =[1,0,...

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Abstract

The invention discloses a photovoltaic power generating assembly fault detection and identification method based on digital twinning. The method comprises the following steps: detecting and outputting a characteristic quantity y (t) in a physical entity of a to-be-detected photovoltaic power generating assembly, wherein the photovoltaic power generating assembly comprises a solar cell assembly and a DC-DC converter; constructing a digital twin body having the same physical entity structure as the to-be-detected photovoltaic power generating assembly, and calculating and outputting the measurement characteristic quantity z (t) of the photovoltaic power generating assembly in the digital twin body; calculating and outputting a residual vector gamma (t) according to the characteristic quantity y (t) and the measured characteristic quantity z (t); outputting a detection result according to the residual vector gamma (t); when a fault exists in the detection result, calculating and outputting an L2 inner product according to the residual vector gamma (t) and a fault characteristic value fi, wherein the fault characteristic value fi is calculated by the residual vector gamma (t) and a 2-norm gamma (t) 2 of the residual vector gamma (t); and outputting a fault type according to the L2 inner product. The method can be used for detecting whether the photovoltaic power generating assembly has a fault or not and identifying the type of the generated fault. The reliability and the practicability are high.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaic power generation, in particular to a method for detecting and identifying faults of photovoltaic power generation components based on digital twins. Background technique [0002] As environmental issues receive more and more attention, the energy market is increasingly interested in photovoltaic power generation systems. 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 Applications(China)
IPC IPC(8): H02S50/10
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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