Optically-Controlled Shunt Circuit for PV Panel Shading Bypass
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Solution Overview
Problem
Current maximum power point tracking (MPPT) techniques in photovoltaic systems often sacrifice energy from unshaded cells to optimize power output by removing partially shaded panels, leading to inefficiencies due to introduced resistance from shading, which reduces overall power generation.
Innovation Solution
The implementation of an optically-controlled shunt (OCS) circuit within photovoltaic panels that samples light conditions and dynamically bypasses shaded cells, either completely, partially, or not at all, to maximize power delivery by adjusting the switch state based on available light, thereby preventing shaded cells from blocking current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MPPT techniques remove partially shaded panels from the string to maximize power flow, then the efficiency of the string is improved, but the energy generated by unshaded cells in those panels is wasted
Solution Approach 1:
The patent divides the photovoltaic panel into individually controllable cells, each with its own shunt circuit. This segmentation allows selective bypassing of only the shaded cells while keeping unshaded cells active, rather than removing entire panels from the string as in conventional MPPT approaches.
Solution Approach 2:
The patent applies different operational states to different cells within the same panel based on their local light conditions. Each cell can be independently bypassed or activated according to whether it is shaded or unshaded, optimizing the contribution of each local segment to the overall power output.
2Reliability
If shaded panels are removed from the string to optimize power flow, then the resistance introduced by shading is eliminated, but the overall power generation capability is reduced
Solution Approach 1:
The patent implements dynamic control of shunt circuits that can rapidly switch between bypass and active states based on real-time light conditions. This dynamic adjustment allows the system to adapt to changing shading patterns while maintaining optimal power generation from all available unshaded cells.
Solution Approach 2:
The patent uses light sensors to provide feedback about the shading status of each cell, which then controls the shunt circuit state. This feedback mechanism enables the system to automatically respond to shading conditions and optimize power flow without manual intervention or removal of panels.
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
This solution enhances the overall efficiency of photovoltaic systems by allowing unshaded cells to contribute to power generation while minimizing the impact of shaded cells, thereby maximizing power output and reducing energy loss.
Implementation Method 1
The light sampler 202 comprises a photodiode 302 that is exposed to the light 208 available at the PV cell 108
Implementation Method 2
For solar energy, photovoltaic panels arranged in an array typically provide the means to convert solar energy into electrical energy
Data Source
AI summary
An optically-controlled shunt (OCS) circuit includes a switch and a light sampler. The light sampler is coupled to the switch and is configured to sample light at a photovoltaic (PV) cell corresponding to the OCS circuit and to turn on the switch when the sampled light comprises insufficient light for the PV cell. The light sampler may also be configured to turn off the switch when the sampled light comprises sufficient light for the PV cell. The light sampler may further be configured to partially turn on the switch when the sampled light comprises adequate light for the PV cell and to turn off the switch when the sampled light comprises full light for the PV cell. The switch could include a transistor, and the light sampler could include a photodiode.