Power Conditioner Shadow Detection for PV Module MPPT
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Solution Overview
Problem
Existing photovoltaic cell systems face reduced power generation efficiency due to unnecessary suspension of power generation for abnormality detection, which requires periodic measurement of short-circuit current and open-circuit voltage, leading to inefficient maximum power point tracking.
Innovation Solution
A power conditioner and control method that performs a maximum power point search by detecting changes in current and voltage over time, identifying adjacent photovoltaic cell modules with significant changes, and predicting shadow occurrences to minimize power generation suspension and maintain efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a maximum power point search is performed by measuring actual generated power while varying current or voltage over the entire adjustable range, then the maximum power point can be accurately identified even with multiple peaks, but power generation efficiency is reduced due to unnecessary maximum power point search in normal operating conditions
Solution Approach 1:
The system performs preliminary detection of abnormal states (such as shadow casting) before initiating a full maximum power point search. By detecting changes in current and voltage that indicate abnormal conditions, the system prepares to perform the search only when necessary, avoiding unnecessary searches during normal operation and thus maintaining power generation efficiency while ensuring accurate maximum power point identification when needed
Solution Approach 2:
The system changes the operating parameters (current or voltage) over the entire adjustable range only when an abnormal state is detected. During normal operation, the system maintains current parameters to avoid reducing power generation efficiency. When abnormality is detected, the system then varies parameters across the full range to accurately identify the maximum power point, thus dynamically adjusting parameter exploration based on operational conditions
2Reliability
If photovoltaic cell abnormality is detected periodically by suspending power generation to measure short-circuit current and open-circuit voltage, then abnormal states can be identified, but power generation efficiency is reduced due to unnecessary suspension of power generation even when no abnormality has occurred
Solution Approach 1:
The system uses the photovoltaic cell's own operating characteristics (current and voltage changes during normal power generation) to detect abnormal states. Instead of suspending power generation to perform separate measurements, the system continuously monitors parameters during normal operation, allowing the photovoltaic cell to serve both power generation and self-diagnosis functions simultaneously, thus maintaining power generation efficiency while ensuring reliable abnormality detection
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 solution allows for efficient maximum power point tracking by reducing unnecessary power generation suspension, thereby enhancing overall power generation efficiency by performing targeted maximum power point searches based on detected and predicted shadow impacts.
Implementation Method 1
Photovoltaic power generation is a known way of generating power by converting sunlight into power
Data Source
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AI summary
A power conditioner (12) includes a detector (15) and a controller (19). The detector (15) detects electrical output of each of a plurality of photovoltaic cell modules (11). The controller (19) compares a change over time in the electrical output detected by the detector (15) with a threshold. When the change over time exceeds the threshold for a plurality of photovoltaic cell modules (11) and the photovoltaic cell modules (11) are in a predetermined positional relationship, the controller (19) causes the photovoltaic cell modules (11) to perform a maximum power point search.