Electret Vibration Harvester Electrode Layout for Lower Output Impedance
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Solution Overview
Problem
Existing vibration-driven energy harvesting elements face challenges in efficiently generating power due to limitations in the design of fixed and movable electrodes, leading to inefficiencies in power generation.
Innovation Solution
The energy harvesting element incorporates a configuration with first and second electrodes, a movable part with third and fourth electrodes, and electrets, allowing for efficient power generation through changes in electrostatic capacitance caused by vibration, coupled with a rectifier to convert alternating current to direct current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fixed and movable electrode designs are used, then the device structure is simple, but power generation efficiency is low
Solution Approach 1:
The electrode system is divided into multiple independent electrodes (first fixed electrode, second fixed electrode, third movable electrode, fourth movable electrode) with distinct functions. Each electrode can be independently controlled or positioned, allowing optimized charge distribution and capacitance modulation during vibration, thereby improving power generation efficiency without creating a monolithic complex structure.
Solution Approach 2:
The patent transitions from a single-plane electrode arrangement to a multi-dimensional configuration where electrodes are arranged in both fixed and movable planes. The third and fourth electrodes are positioned on a movable part that can displace relative to the fixed electrodes, creating a three-dimensional electrostatic field that enhances charge induction and power generation during vibration.
2Reliability
If conventional electrode configurations are used, then manufacturing is simpler, but output impedance is higher
Solution Approach 1:
The patent combines multiple electrode pairs into a unified energy harvesting system where the first and second fixed electrodes work together with the third and fourth movable electrodes. This merging of multiple electrostatic generators into a single integrated device reduces overall output impedance by providing multiple parallel charge pathways, while the common movable part structure maintains manufacturing simplicity.
3Power
If conventional power generation methods are used, then fewer components are needed, but voltage and current output is insufficient
Solution Approach 1:
The patent ensures continuous power generation during vibration by maintaining overlapping regions between all electrode pairs throughout the motion range. The movable part with third and fourth electrodes continuously modulates the capacitance of multiple electrostatic generators simultaneously, ensuring that at least one electrode pair is always in a charge-inducing configuration, thereby maximizing voltage and current output throughout the vibration cycle.
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 configuration enables efficient power generation, reduces output impedance, and lowers manufacturing costs by optimizing voltage and current output, while minimizing the need for complex component selection.
Implementation Method 1
power generation is performed in such a way that a change of the area of a portion where the fixed electrode and the movable electrodes face each other causes change of the charge induced by an electret, which changes potential difference between the fixed electrodes and the movable electrodes to generate an electromotive force
Data Source
AI summary
An energy harvesting element capable of efficiently generating power is provided. The energy harvesting element generates power by vibration, and includes a first electrode and a second electrode, a member having a third electrode electrically connected to the second electrode, and facing the first electrode, and a fourth electrode relatively fixed to the third electrode without being electrically connected to the third electrode, and electrically connected to the first electrode and facing the second electrode, the member being provided between the first electrode and the second electrode, and an electret provided in one of the first electrode and the third electrode, and one of the second electrode and the fourth electrode.