Asymmetric Comb Electrode Vibration Harvester for Vertical Orientation
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Solution Overview
Problem
Vibration-driven energy harvesters experience reduced power generation efficiency when installed vertically due to gravitational forces causing the movable unit to move towards the ground, resulting in smaller gap distances and reduced vibration amplitudes.
Innovation Solution
The design incorporates asymmetrical comb electrode structures with varying gap distances and electrostatic forces between movable and fixed electrodes, ensuring the movable unit vibrates with greater amplitude by positioning the electrode with a larger gap distance closer to the ground and adjusting the electrostatic forces to prevent downward displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vibration-driven energy harvester is installed in a vertical orientation with the first movable comb electrode positioned closer to the ground, then the device can be installed in space-saving vertical configurations, but the gap distance between the first movable comb electrode and the first fixed comb electrode becomes smaller, causing the movable unit to contact the fixed electrode and reducing vibration amplitude and power generation efficiency
Solution Approach 1:
The patent applies asymmetry by making the gap distances between comb electrodes non-uniform. Specifically, the gap distance between the first movable comb electrode and first fixed comb electrode is made different from the gap distance between the second movable comb electrode and second fixed comb electrode. This asymmetric design allows the device to be installed in vertical orientations without the movable unit contacting the fixed electrodes, as the varying gap distances prevent symmetric contact that would occur with uniform gaps, thereby maintaining vibration amplitude and power generation efficiency while enabling vertical installation flexibility
2Adaptability or versatility
If the vibration-driven energy harvester is installed in a vertical orientation, then space utilization is improved, but gravitational force causes the movable unit to move toward the ground, reducing the gap distance and vibration amplitude
Solution Approach 1:
The asymmetric gap distance design compensates for gravitational effects in vertical installations. By having different gap distances at different positions, the design ensures that when gravity causes the movable unit to shift downward, the larger gap provides sufficient clearance to prevent contact, thereby maintaining adequate vibration amplitude. This allows vertical installation capability while mitigating the negative impact of gravity on vibration amplitude
3Ease of manufacture
If equal gap distances are used between all comb electrodes, then the structure is simpler and easier to manufacture, but the movable unit contacts the fixed electrodes during vibration in vertical installations, reducing power generation efficiency
Solution Approach 1:
The patent implements asymmetry by specifying that the gap distance between the first movable comb electrode and first fixed comb electrode differs from the gap distance between the second movable comb electrode and second fixed comb electrode. This asymmetric configuration prevents the movable unit from contacting the fixed electrodes during vibration in vertical installations, thereby maintaining power generation efficiency. The asymmetry is simple to implement in the manufacturing process, requiring only different gap specifications rather than complex adaptive mechanisms
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 approach minimizes the reduction in power generation efficiency caused by gravity, allowing the vibration-driven energy harvester to maintain higher efficiency even when installed vertically by optimizing the vibration amplitude and electrode interactions.
Implementation Method 1
electric charges induced via the electrets also change. As a result, the voltage between the first movable comb electrode and the first fixed comb electrode and the voltage between the second movable comb electrode and the second fixed comb electrode change and power is thus generated
Implementation Method 2
a movable unit supported by an elastic support member
Data Source
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AI summary
A vibration-driven energy harvester includes: a base; a movable assembly that includes a first movable electrode and a second movable electrode; a first fixed electrode disposed so as to face opposite the first movable electrode; a second fixed electrode disposed so as to face opposite the second movable electrode; an elastic support member having a fixed end fixed to the base, the elastic support member supporting the movable assembly; a first electret formed at least at one of the first movable electrode and the first fixed electrode; and a second electret formed at least at one of the second movable electrode and the second fixed electrode, wherein: a gap distance between a front end of the second movable electrode and a facing surface of the second fixed electrode facing the front end of the second movable electrode is different from a gap distance between a front end of the first movable electrode and a facing surface of the first electrode facing the front end of the first movable electrode.