Solar Bicycle Wheel Module Shading Avoidance
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Solution Overview
Problem
Solar bicycles with solar modules arranged laterally on wheels face significant power generation losses due to partial shading from bicycle frame struts and fork blades, which can cause the electrical voltage and current to collapse, especially when these structures cast shadows on the modules as they rotate.
Innovation Solution
The solar modules are arranged in a manner that ensures no two adjacent modules in the circumferential direction are shaded simultaneously by strategically spacing them at least as wide as the shadow cast by the thickest frame strut or fork blade, with radially arranged modules connected in series and circumferentially offset modules connected in parallel, using diodes to prevent shaded modules from affecting unshaded ones, and allowing for air permeability between the modules to reduce wind sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If solar modules are arranged laterally on the wheels, then the area for power generation is increased, but frame struts and fork blades cast shadows on the modules causing power generation loss
Solution Approach 1:
The solar modules are divided into multiple segments arranged around the wheel circumference, with each segment positioned at specific angular intervals. This segmentation allows the system to maximize the total area for power generation while ensuring that no single shadow-casting structure (frame strut or fork blade) can block all modules simultaneously, thus reducing power generation loss.
2Area of stationary object
If solar modules are placed close together to maximize area, then more modules can be installed, but shadow from frame structures affects multiple modules simultaneously
Solution Approach 1:
Each solar module is positioned at a specific local angular position around the wheel, creating a non-uniform distribution pattern. This local quality approach ensures that modules are spaced such that when one module is in shadow, adjacent modules remain exposed to sunlight, optimizing the overall power generation area while minimizing shadow interference.
3Area of stationary object
If solar modules are arranged in a compact circular pattern, then the area utilization is maximized, but wind resistance increases
Solution Approach 1:
The solar module arrangement creates a porous or open structure around the wheel, with gaps between modules that allow wind to pass through. This porous configuration maintains high wheel surface utilization for power generation while reducing wind resistance by enabling airflow through the module arrangement rather than creating a solid barrier.
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 arrangement minimizes the negative impact of shading on power generation, allowing all solar modules to generate electricity effectively, with a maximum reduction of 10% in solar power generation, and increases the area used for power generation by allowing more modules to be placed on the wheel, resulting in a higher electrical voltage.
Implementation Method 1
Solar modules arranged laterally on at least one of the front and rear wheels generate electricity
Data Source
Figure 1
AI summary
The invention relates to a solar-powered bicycle (1) with an electric motor (7) for drive assistance and with solar modules (10) arranged laterally on the wheels (2) for charging a battery (8). The invention proposes to arrange the solar modules (10) at a circumferential distance such that the blades (12) of a bicycle fork (13) and frame stays (14) are never (partially) shaded by more than one of the solar modules (10) arranged circumferentially on the wheels (2) at any one time. This achieves a high efficiency of power generation with the solar modules (10).