MEMD Energy Harvesting via Floating Gate Charging
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Solution Overview
Problem
The lifetime of existing electrostatic converters for harvesting electrical energy from mechanical movements is limited by the stability of the charge implanted in electrets, and they often require electrets for operation, which can restrict their effectiveness and durability.
Innovation Solution
A micro-electromechanical device (MEMD) with a floating gate charging device (FGCD) that selectively and controllably charges conductive elements using tunnel oxide, allowing for charge displacement measurement and rectification, enabling efficient energy harvesting and sensing without relying on electrets, with optional multiple FGCDs and conductive elements for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If electrets are used in electrostatic converters, then charge stability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the electret component from the electrostatic converter design. By using a simple conductive element that can be charged through contact with a charged object, the invention eliminates the need for complex electret structures while maintaining charge stability functionality.
Solution Approach 2:
The patent employs simple conductive elements that can be easily recharged by contacting external charged objects. This approach replaces expensive, complex electrets with inexpensive, easily replaceable conductive elements that achieve the same functional result through periodic recharging.
2Stability of the object's composition
If electrets are used in electrostatic converters, then charge stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent removes the electret component from the electrostatic converter design. By using a simple conductive element that can be charged through contact with a charged object, the invention eliminates the need for complex electret structures while maintaining charge stability functionality.
3Use of energy by moving object
If conventional electrostatic converters are used, then energy harvesting capability is achieved, but device wear increases reducing lifetime
Solution Approach 1:
The patent replaces the mechanical friction-based contact charging mechanism with an electromagnetic induction-based wireless charging mechanism. This substitution eliminates mechanical wear while maintaining the ability to recharge conductive elements, thereby extending device lifetime.
4Stability of the object's composition
If electrets are used in electrostatic converters, then charge stability is improved, but ease of operation decreases
Solution Approach 1:
The patent enables the conductive element to automatically recharge by contacting external charged objects in the environment. This self-service mechanism eliminates the need for manual intervention to maintain charge stability, improving ease of operation while preserving charge stability.
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 MEMD achieves improved energy harvesting and sensing capabilities with increased charge stability and reduced wear, allowing for rapid charging and discharging cycles, and can operate electret-free, enhancing device usability and compatibility with existing technologies.
Implementation Method 1
floating gate charging device (FGCD) that selectively and controllably charges conductive elements using tunnel oxide
Implementation Method 2
electrostatic converter for converting mechanical movement into electrical energy
Implementation Method 3
variable capacitor structure comprising a first and a second capacitor plate separated by a dielectric
Implementation Method 4
The induced AC may be rectified by rectifier circuitry to generate a direct current
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
The present invention discloses, inter alia, a micro-electromechanical device (MEMD) for sensing and for harvesting electrical energy responsive to being subjected to mechanical forces, comprising at least one first conductive element fixedly mounted on a first support, wherein the at least one first conductive element is chargeable with electrons; and at least one second conductive element inertia-mounted on a second support such that the first and second supports are electrically isolated from each other.