Photovoltaic Cell Defect Detection Using Dual Infrared States

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Solution Overview

Problem

Current methods for detecting solar cells in photovoltaic plants are limited by the need for indoor detection using external light sources, which increases costs and complexity due to the large area coverage and require extensive wiring, making it difficult to efficiently detect defects in solar cells.

Innovation Solution

A method that uses a sunlight source to obtain first and second infrared images of solar cells in short-circuit and other states, allowing for defect detection without artificial lighting, reducing the need for indoor movement and wiring reconstruction, and utilizing an inverter to control the solar cells' operation states for accurate imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If outdoor detection is performed using natural sunlight, then detection area coverage is improved and wiring complexity is reduced, but detection precision may deteriorate due to ambient light interference

Engineering Contradiction:
Improvedetection area coverageVSAvoiddetection precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies periodic action by controlling the inverter to switch between different operation modes (MPPT mode and constant power mode) at specific time intervals. The infrared camera captures images during constant power mode when the solar cell emits stronger infrared signals, while avoiding capture during MPPT mode when signals are weaker. This periodic switching enables precise defect detection outdoors using natural sunlight without requiring artificial lighting.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes operational parameters by controlling the inverter to switch between different power output modes. During constant power mode, the solar cell operates at a higher power level which generates stronger infrared emission signals. This parameter change amplifies the infrared signal strength during natural sunlight conditions, improving detection precision outdoors without needing artificial light sources.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If indoor detection with external light source is used, then detection precision is improved, but device complexity and operational costs increase due to wiring reconstruction requirements

Engineering Contradiction:
Improvedetection precisionVSAvoidwiring complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by utilizing the solar cell's own infrared emission characteristics during normal operation. Instead of requiring external light sources and complex wiring setups, the system uses the solar cell's inherent photovoltaic effect and infrared emission properties. The inverter controls the solar cell to operate in constant power mode, where it emits strong infrared signals that can be captured by the infrared camera, enabling precise detection without any external illumination equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent makes the inverter multi-functional by enabling it to serve both its primary power conversion function and a secondary defect detection function. By controlling the inverter to switch between MPPT mode and constant power mode, it simultaneously manages power generation while creating optimal conditions for infrared imaging. This eliminates the need for separate detection equipment and wiring infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If solar cells are controlled to operate in different states, then defect detection accuracy is improved, but operational time is increased due to multiple imaging requirements

Engineering Contradiction:
Improvedefect detection accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses periodic action by implementing time-based control where the inverter switches between MPPT mode and constant power mode in sequential intervals. The system captures infrared images during constant power mode when emission signals are strong, and skips capture during MPPT mode when signals are weak. This periodic switching pattern optimizes the detection process by capturing images only during optimal signal conditions, improving accuracy without requiring excessive operational time.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies preliminary action by pre-controlling the inverter to enter constant power mode before image capture is initiated. This ensures that the solar cell is already in the optimal operational state with strong infrared emission signals when the infrared camera begins capturing images, eliminating the need for extended operation in multiple modes and reducing total detection time while maintaining high accuracy.

Inventive Principle:
Principle #10Preliminary action

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

Enables comprehensive and cost-effective detection of solar cells in photovoltaic plants by eliminating the need for artificial lighting and on-site wiring, improving detection accuracy and reducing operational costs while allowing for precise identification of defects.

Implementation Method 1

The photovoltaic module converts illuminating light energy into electrical energy

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

The photovoltaic module converts illuminating light energy into electrical energy, and emits an infrared signal under the drive of the electrical energy

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 3

The infrared signal is collected by using an infrared camera to obtain an infrared image

Methodology Applied
Scientific EffectInfrared detection: Infrared Radiation

Data Source

PatentEP4009517B1Method, device and system for detecting cell sheet of photovoltaic power station
Publication Date: 2024.07.31 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4009517B1 patent drawingFigure 1
  • EP4009517B1 patent drawingFigure 2
  • EP4009517B1 patent drawingFigure 3

AI summary

This application discloses a method, an apparatus, and a system for detecting a solar cell of a photovoltaic plant, belonging to the communications field. The method includes: obtaining a first infrared image and a second infrared image, where the first infrared image includes infrared image information corresponding to an ambient infrared signal reflected by a to-be-detected solar cell operating in a short-circuit state, the second infrared image includes infrared image information corresponding to an infrared signal emitted by the to-be-detected solar cell operating in a first state and infrared image information corresponding to an ambient infrared signal reflected by the to-be-detected solar cell, and the first state is another state other than the short-circuit state; and detecting, based on the first infrared image and the second infrared image, whether the to-be-detected solar cell has a defect. This application can reduce difficulty and operation and maintenance costs of photovoltaic module detection.