Photovoltaic Module Internal Protection Circuit with Independent Columns
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Solution Overview
Problem
Existing half-cell photovoltaic modules suffer from low practical utilization rates and increased failure risks due to inefficient internal protection circuit designs, leading to reduced power generation capacity and stability, especially during environmental tests like hot spot tests.
Innovation Solution
An internal protection circuit structure for photovoltaic modules with independent power generating units, where solar cells are divided into six columns each with specific polarity connections and three separate junction boxes with diodes, allowing for improved current flow and reduced power loss, enhancing the utilization rate and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional internal protection circuits connect two strings in parallel and then three strings in series with bypass diodes, then the circuit structure is simple and compatible with existing manufacturing processes, but the practical utilization rate of electricity generation is low (about 33% for vertical outgoing, 60% for lateral outgoing) and power generation capacity is lost when substrings are shadowed
Solution Approach 1:
The patent divides the 60 solar cells into six independent columns (first through sixth columns) instead of traditional string configurations. Each column can independently generate and output electricity, allowing partial operation when some columns are shadowed. This segmentation increases the practical utilization rate from 33-60% to approximately 83% by ensuring that unshadowed columns continue to contribute to power generation.
Solution Approach 2:
The patent introduces a busbar as an intermediary component that collects current from multiple columns and distributes it to junction boxes. This intermediary structure enables flexible current routing and allows the system to maintain high utilization rates by aggregating power from all functional columns regardless of their individual shadowing status.
2Reliability
If bypass diodes are connected in parallel to protect solar cells from reverse bias, then the cells are protected from damage, but two-thirds or two-fifth of the substrings are bypassed and lose power generation capacity when shadowed
Solution Approach 1:
By segmenting the module into six independent columns with individual junction boxes, the patent eliminates the need for bypass diodes that would force large portions of the module into non-generating mode. Each column operates independently, so shadowing affects only that specific column rather than causing bypass of multiple substrings, thereby maintaining higher overall power generation capacity.
Solution Approach 2:
The patent applies local protection measures at each junction box level rather than global bypass diodes. Each junction box independently manages the electrical characteristics of its associated column, allowing localized shadowing to be handled without affecting the operational status of other columns, thus preserving power generation capacity.
3Productivity
If six columns of solar cells are connected with specific polarity arrangements and three separate junction boxes, then the practical utilization rate increases by about 23% and reliability improves, but the circuit structure becomes more complex
Solution Approach 1:
The patent merges the functions of multiple strings and bypass diodes into a unified six-column architecture with junction boxes. Instead of complex series-parallel combinations with bypass paths, the design combines all six columns in parallel configuration, simplifying the overall circuit topology while achieving higher utilization rates through independent column operation.
Solution Approach 2:
The junction boxes serve multiple functions: they collect current from individual columns, provide electrical connections to the busbar, and enable independent operation of each column. This multi-functionality reduces the need for additional protective components and simplifies the overall circuit structure despite the increased column segmentation.
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 proposed design increases the practical utilization rate of electricity generation by about 23% compared to existing methods, reduces power generation capacity loss, and lowers the likelihood of failure during environmental tests, while being compatible with conventional manufacturing processes without additional costs.
Implementation Method 1
Each separate junction box is provided with a diode
Data Source
AI summary
The present invention discloses an internal protection circuit structure of photovoltaic modules having independent power generating unit, which includes a plurality of solar cells. The plurality of solar cells is combined to form a power generating unit A and a power generating unit B. Polarities of the upper ends of the substrings of solar cell are positive, negative, positive, negative, positive, and negative sequentially from the first column of A to the sixth column of A. Polarities of the lower ends of the substrings of solar cell are positive, negative, positive, negative, positive, and negative sequentially from the first column of B to the sixth column of B. Moreover, the busbar is provided with three separate junction boxes.