Photovoltaic Cell Shunt Fault Detection by Light Shielding Current Response
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Solution Overview
Problem
Existing methods for determining abnormalities in the parallel resistance component of photovoltaic cells in a photovoltaic module are complex and require modulated light irradiation, making them inefficient and burdensome.
Innovation Solution
A photovoltaic module abnormality determination system that acquires the output current and light shielding rate of a target photovoltaic cell, determining abnormalities in the parallel resistance component based on the range of output current change with varying light shielding rates, without using modulated light irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If modulated light irradiation is used to determine abnormalities in photovoltaic cells, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent extracts the essential measurement function from the complex modulated light system. Instead of using modulated light irradiation and synchronization signal detection, the invention directly measures output current at different light shielding rates to determine abnormalities. This removes the need for AC current clamp sensors, lock-in amplifiers, and modulated light sources, significantly simplifying the system while maintaining measurement capability.
Solution Approach 2:
The photovoltaic module itself serves as the measurement tool. By measuring its own output current under different light shielding conditions, the system eliminates the need for external complex measurement equipment. The module's electrical characteristics are used directly to detect abnormalities in parallel resistance components without requiring separate detection systems.
2Measurement precision
If modulated light irradiation and light shielding methods are used, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent removes the burdensome light shielding operations and modulated light irradiation procedures. The inspection process is reduced to simply measuring output current at two different light shielding rates (0% and a predetermined rate), eliminating the need for complex mask positioning, light modulation, and synchronization signal extraction that characterized previous methods.
Solution Approach 2:
The invention changes the measurement parameter from detecting synchronization signals in modulated light systems to directly measuring output current magnitude at different light shielding rates. This parameter change simplifies the operation to basic electrical measurement while maintaining the ability to evaluate parallel resistance components through the relationship between light shielding rate and current change.
3Reliability
If electro-luminescence method is used to detect PID phenomenon, then reliability is improved, but productivity deteriorates
Solution Approach 1:
The patent enables continuous power generation during inspection. Unlike the electro-luminescence method requiring complete power generation stop, this invention measures output current during normal operation at different light shielding rates. The photovoltaic module continues to generate power throughout the inspection process, eliminating downtime and improving productivity while maintaining detection capability for parallel resistance abnormalities including PID effects.
Solution Approach 2:
The system uses the photovoltaic module's own power generation output as the measurement signal. By measuring the output current that the module naturally produces during operation, the inspection process requires no external power injection or stopping of power generation. The module serves both as the object of inspection and the source of measurement signals, enabling continuous operation and high inspection efficiency.
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 efficient and simple determination of abnormalities in the parallel resistance component of photovoltaic cells, reducing the complexity and burden of existing methods while maintaining accuracy.
Implementation Method 1
irradiating one photovoltaic cell of a plurality of photovoltaic cells connected in series to constitute a photovoltaic module with modulated light
Implementation Method 2
a first photovoltaic cell, which is one of the m photovoltaic cells, is shielded from light
Data Source
AI summary
A photovoltaic module abnormality determination system that determines presence or absence of an abnormality in a parallel resistance component of each of a plurality of photovoltaic cells connected in series to constitute a photovoltaic module, acquires an output current of the photovoltaic module during power generation, acquires a light shielding rate of a determination target photovoltaic cell for the presence or absence of the abnormality in a parallel resistance component, determines that the abnormality is not present in the parallel resistance component of the determination target photovoltaic cell in a case where a light shielding rate range of output current change, in which the output current of the photovoltaic module changes in a case where the light shielding rate of the determination target photovoltaic cell is changed, is between a light shielding rate of 0 and 1 of the determination target photovoltaic cell, and determines that the abnormality is present in the parallel resistance component of the determination target photovoltaic cell in a case where a light shielding rate range of non-output current change, in which the output current of the photovoltaic module hardly changes even in a case where the light shielding rate of the determination target photovoltaic cell is changed, is between the light shielding rate of 0 and 1 of the determination target photovoltaic cell.