PV Module Fault Detection Using TDR and Mechanical Agitation

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Solution Overview

Problem

Photovoltaic (PV) module operations are hindered by intermittent electrical pathway failures, which are difficult to detect and can lead to reduced output or complete failure, as existing methods lack effective means to identify and isolate these faults in series and parallel connections within PV modules.

Innovation Solution

An end-of-line electrical pathway testing system utilizing Time Domain Reflectometry (TDR), mechanical agitation, dark current/voltage testing, and thermographic imaging to detect and isolate intermittent faults in PV modules, employing forward and reverse bias testing to identify faulty connections, and using a microcontroller to provide pass/fail indicators based on sampled data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional testing methods are used for PV modules, then manufacturing simplicity is maintained, but intermittent electrical pathway failures cannot be detected

Engineering Contradiction:

Improvedetection of intermittent electrical pathway failuresVSAvoidtesting system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrical pathway testing is segmented into multiple independent testing phases: initial resistance measurement, mechanical agitation testing, and post-agitation resistance measurement. Each phase targets specific aspects of intermittent failures, allowing comprehensive detection without requiring a single complex testing device.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Mechanical agitation is applied preliminarily to the PV module before final electrical pathway verification. This preliminary mechanical stress activates intermittent connection issues that would otherwise remain hidden, enabling their detection in subsequent electrical measurements.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If PV modules are thoroughly tested for all electrical pathways, then detection precision is improved, but testing time increases

Engineering Contradiction:

Improvefault detection precisionVSAvoidtesting time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of continuously monitoring all electrical pathways throughout the module lifecycle, the system applies partial excessive action by subjecting the module to intense mechanical agitation at a critical intermediate stage. This concentrated stress application reveals intermittent failures that would require much longer continuous monitoring to detect naturally.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The testing process uses periodic action by conducting measurements at discrete time points: before mechanical agitation, during/after agitation, and after potting compound application. This periodic sampling captures intermittent failures at their most vulnerable moments without requiring continuous monitoring.

Inventive Principle:

Principle #19Periodic action

3Reliability

If mechanical agitation is applied to detect intermittent failures, then fault detection capability is improved, but module stability during testing deteriorates

Engineering Contradiction:

Improveintermittent failure detectionVSAvoidmodule stability during testing

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The PV module is potted with stabilizing compound beforehand to provide structural cushioning during mechanical agitation testing. This pre-applied stabilization allows the module to withstand the mechanical stress required to reveal intermittent failures without suffering permanent damage or excessive movement.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively identifies and isolates intermittent electrical pathway failures in PV modules, enabling early detection and potential repair, thereby ensuring consistent module performance and reducing the need for extensive reworking or discarding of modules.

Implementation Method 1

An end-of-line electrical pathway testing system utilizing Time Domain Reflectometry (TDR)... to detect and isolate intermittent faults in PV modules

Methodology Applied

Scientific EffectTime Domain Reflectometry:

Implementation Method 2

...and thermographic imaging to detect and isolate intermittent faults in PV modules

Methodology Applied

Scientific EffectThermographic imaging: Thermography

Implementation Method 3

employing forward and reverse bias testing to identify faulty connections

Methodology Applied

Scientific EffectElectrical bias testing: Electric Field

Data Source

PatentUS12081168B2Electrical pathway intermittent fault detection

Publication Date: 2024.09.03 MAXEON SOLAR PTE LTD

AI summary

Testing to detect intermittent electrical pathways is described. Applied currents may be reversed to fully test all components of a workpiece. Various testing methodologies may be employed. These methodologies may include Time Domain Reflectometry (TDR), mechanical agitation, dark current/voltage testing, (dark IV), i.e., electrical testing of a workpiece using applied electricity, and thermographic imaging, e.g., infra-red thermal imaging. The sensed voltage during agitation may be compared to a benchmark voltage to determine whether or not an intermittent failure exists.