Solar Cell Module Error Detection Using Modulated Light
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Solution Overview
Problem
Existing methods for determining abnormal photovoltaic cells in a module are inaccurate due to the sealed nature of photovoltaic modules, which prevents direct measurement of cell voltage and relies heavily on ambient temperature, leading to reduced precision in identifying failed cells.
Innovation Solution
An abnormality determination system that includes a modulated light radiation unit, phase detection unit, and determination unit, where modulated light is radiated to individual cells, and a lock-in amplifier outputs a signal indicating the cell's state, allowing for precise identification of abnormal cells based on changes in current and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photovoltaic module is sealed with resin to protect the cells, then the module's durability and protection are improved, but the ability to measure individual cell voltage is lost
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the relationship between module current and individual cell voltage characteristics. Instead of directly measuring sealed cell voltages, the system uses current measurements combined with the known electrical characteristics of series-connected cells to infer individual cell states, effectively mediating between the sealed structure and measurement needs
2Ease of operation
If cell temperature is used to determine cell failure, then the measurement can be easily obtained through infrared camera, but the determination precision is reduced due to strong ambient environment influence
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring module current and comparing it against expected values for each cell. The system uses the electrical feedback from current measurements to identify deviations that indicate cell failure, creating a closed-loop detection system that compensates for environmental temperature variations by relying on electrical rather than thermal signatures
3Device complexity
If only module-level current measurement is used, then the system is simple, but the ability to identify which specific cell has failed is lost
Solution Approach 1:
The patent applies segmentation by dividing the module-level current measurement into cell-specific information. By analyzing the current characteristics and using the known series connection topology, the system segments the overall current signal to identify which specific cell is causing the deviation, effectively partitioning the measurement information to locate individual cell failures
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 accurate determination of abnormal cells by analyzing changes in voltage and current, providing a more precise method than relying solely on temperature measurements, thus improving the identification of failed cells within a photovoltaic module.
Implementation Method 1
A modulated light radiation unit 11 radiates modulated light ML to one photovoltaic cell C1 among a plurality of photovoltaic cells C1 to C5 included in the photovoltaic module M
Implementation Method 2
a phase detection unit 12 configured to output a signal LAo indicating a state of the photovoltaic cell C1 according to a current change in the photovoltaic module M and a reference signal RS indicating a phase of the modulated light ML
Data Source
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AI summary
An abnormality determination system (1) for a photovoltaic module (M) including a plurality of photovoltaic cells (C1, C2, C3, C4, C5) connected in series includes: a modulated light radiation unit (11) configured to radiate modulated light to one photovoltaic cell among the plurality of photovoltaic cells (C1, C2, C3, C4, C5); a phase detection unit (12) configured to output a signal in accordance with a state of the one photovoltaic cell according to a signal indicating a power output of the photovoltaic module (M) and a reference signal indicating a phase (frequency) of the modulated light; and a determination unit (13) configured to determine whether the one photovoltaic cell is in an abnormal state according to the signal output from the phase detection unit (12).