Piezoelectric Energy Conversion with Variable Capacitance Amplification
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Solution Overview
Problem
Current methods for converting mechanical energy into electrical energy, such as those using piezoelectric and electrostatic means, are not optimal in terms of efficiency.
Innovation Solution
A device that combines piezoelectric and electrostatic means by associating a piezoelectric element with a capacitor of variable capacitance, where the piezoelectric element's deformation causes a variation in capacitance, amplifying the electrical energy produced through electrostatic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If piezoelectric means are used to convert mechanical energy into electrical energy, then electrical energy can be recovered, but the conversion efficiency is not optimal
Solution Approach 1:
The patent combines piezoelectric means with electrostatic means in a hybrid energy conversion device. The piezoelectric element converts mechanical energy to electrical energy, which then charges an electrostatic capacitor. The capacitor's variable capacitance mechanism amplifies the electrical energy output, resolving the contradiction by merging two conversion mechanisms to achieve both high efficiency and high productivity
Solution Approach 2:
The patent employs variable capacitance in the electrostatic capacitor, where the capacitance parameter changes dynamically during operation. By varying the capacitance (C) while maintaining charge (Q), the voltage (V=Q/C) and stored energy (E=Q²/2C) are amplified. This parameter change enables the system to transform mechanical work into amplified electrical energy, improving both conversion efficiency and energy output
2Productivity
If electrostatic means with variable capacitance are used to amplify electrical energy, then energy amplification is achieved, but the device complexity increases
Solution Approach 1:
The patent designs the electrostatic capacitor to serve multiple functions: energy storage, energy amplification through variable capacitance, and mechanical coupling with the piezoelectric element. The same capacitor structure that stores electrical energy also provides the variable capacitance mechanism for amplification, reducing the need for separate components and thereby limiting the increase in device complexity
Solution Approach 2:
The patent integrates the variable capacitance mechanism within the existing capacitor structure, where movable electrodes are nested between fixed electrodes. This nested configuration allows capacitance variation through mechanical displacement while maintaining a compact overall structure, achieving energy amplification without proportionally increasing device complexity
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 combination significantly increases the efficiency of mechanical energy conversion into electrical energy, allowing for the amplification of electrical energy stored in the capacitor during capacitance reduction, thereby enhancing energy conversion efficiency.
Implementation Method 1
use a piezoelectric material to transform mechanical energy into electrical energy, the mechanical energy causing the deformation of the piezoelectric material and the appearance of electrical charges in the material
Implementation Method 2
a device for recovering mechanical energy in the form of vibration into electrical energy, comprising a plurality of capacitors with variable capacitance, formed by two facing elements carried respectively by a fixed comb and a comb movable, the movable comb being set in motion under the effect of external vibrations and modifying the air gap between the two elements and thus the capacitance of the capacitors
Data Source
Figure 1A~1E
Figure 1C~1D
Figure 2A~3
AI summary
The principal subject of the present invention is a method for converting mechanical energy into electrical energy by means of at least one piezoelectric element and at least one variable capacitor, said method comprising the steps: a) of mechanical deforming the piezoelectric element; b) of recovering the charges produced by the deformation of the piezoelectric element; c) of transferring the charges from the piezoelectric element to the capacitor; d) of modifying the capacitance of the capacitor; and e) of recovering at least some of the electrical energy. The subject of the present invention is also a device for converting mechanical energy into electrical energy, which comprises a piezoelectric element (p) and a variable capacitor (210, 212, 214), said piezoelectric element being capable of transferring charges to said capacitor.