Bifacial Multi-Junction Solar Tracking for Current Balancing
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Solution Overview
Problem
Existing solar tracking devices do not optimize the current production of bifacial multi-junction photovoltaic modules by balancing the illumination of the front and rear faces, limiting efficiency due to unequal light reception by stacked, series-connected junctions.
Innovation Solution
A method that measures and optimizes the orientation of bifacial photovoltaic panels by balancing the current production of stacked, series-connected junctions using sensors to measure front and rear face irradiances, calculating an optimal theoretical orientation, and adjusting panel positioning to equalize and maximize current output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional solar tracking devices follow only the sun's path to maximize upper face illumination, then the current from the upper junction is maximized, but the current from the lower junction is insufficient, limiting the overall module efficiency
Solution Approach 1:
The tracking device dynamically adjusts the panel orientation beyond simple sun-following motion. The system continuously modifies the tilt and azimuth angles based on real-time measurements of front and rear face irradiances, enabling adaptive balancing of light distribution to both faces of the bifacial module throughout the day
Solution Approach 2:
The system employs feedback control by measuring the irradiances on both front and rear faces using sensors, comparing the current distribution between junctions, and adjusting the panel orientation accordingly. This closed-loop control ensures optimal current balancing from both series-connected junctions
2Illumination intensity
If the panel orientation is fixed to face the sun directly, then the upper junction receives maximum light, but the lower junction receives insufficient light, causing current limitation in series-connected configuration
Solution Approach 1:
The system transitions from single-face (mono-facial) optimization to dual-face (bifacial) optimization by utilizing illumination from both the front and rear surfaces of the module. This dimensional expansion of light reception geometry enables both junctions to contribute effectively to current generation
3Ease of manufacture
If the tracking device only maximizes upper face illumination, then mono-facial module efficiency is optimized, but bifacial multi-junction module efficiency is limited due to unbalanced junction illumination
Solution Approach 1:
The tracking device is designed to serve multiple functions: it not only follows the sun's apparent motion but also actively manages the illumination distribution between front and rear faces to optimize current balancing in series-connected junctions. This multi-functional capability enables the same device to benefit both mono-facial and bifacial module configurations
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 method effectively maximizes current production by equalizing the currents generated by bifacial photovoltaic modules, accounting for real characteristics and illumination conditions, thereby enhancing the operational efficiency of solar power plants.
Implementation Method 1
Bifacial photovoltaic modules with tandem-type junctions are based on the pairing of two stacked, series-connected photovoltaic junctions
Implementation Method 2
measuring a front face irradiance Ai on an upper photoactive face of said panel and measuring a rear face irradiance Ar on a lower photoactive face of said panel
Data Source
AI summary
A method for maximizing the current produced by a bifacial photovoltaic solar module including a plurality of cells, each having at least two stacked and series-connected junctions, the module being capable of orientation and including a device for driving its orientation with respect to the sun. The method includes an algorithm including measuring the module's irradiance at the upper face (Ai) on its upper photoactive face, reflective irradiance (Ar) on its lower photoactive face in its initial orientation, and initial current I from the irradiances Ai and Ar, and calculating currents Ijg generated by the stacked junctions from the cells' physical characteristics and I, calculating an optimized theoretical orientation for which equalization and maximization of the theoretical currents Ijtmax is obtained, and positioning the module in the theoretical orientation when an imbalance between Ijtmax and Ijg is greater than a threshold value dIjmax. A module designed for this method.