Variable Capacitor Generator for Wave Energy Harvesting
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Solution Overview
Problem
Existing energy conversion systems that harness environmental forces like sea waves face inefficiencies due to the need for repeated recharging of electrodes, which requires AC/DC conversions and voltage adjustments, leading to power losses.
Innovation Solution
A system utilizing interconnected variable capacitors made of stretchable material, where a power extraction unit directs electrical charge from high-voltage to low-voltage electrodes, and a power control unit senses voltages to optimize energy transfer, allowing for efficient energy extraction from environmental forces without the need for external recharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC/DC conversions and voltage step ups or step downs are used to recharge electrodes, then the electrodes can be recharged, but power losses increase greatly reducing system efficiency
Solution Approach 1:
The system uses the stretchable material's own mechanical energy to directly recharge the capacitor electrodes without external power sources. The stretching action generates electrical charge that automatically flows back to recharge the electrodes, creating a self-sustaining cycle that eliminates the need for AC/DC conversions and external recharging equipment.
Solution Approach 2:
The invention extracts and eliminates the complex power conversion subsystem (AC/DC converters, voltage regulators) from the system. By using direct mechanical-to-electrical energy conversion through the stretchable material, the system removes the intermediate conversion steps that cause power losses.
2Loss of energy
If an internal source is used for recharging electrodes, then system efficiency increases greatly, but the system complexity increases
Solution Approach 1:
The invention merges the energy generation and energy storage functions into a single integrated system. The stretchable material with embedded electrodes serves both as the mechanical actuator and as the energy storage capacitor, eliminating the need for separate power conversion equipment and control systems.
Solution Approach 2:
The stretchable material performs multiple functions: it acts as the mechanical component that responds to environmental forces, generates electrical charge through deformation, and serves as the dielectric medium for capacitor operation. This multi-functionality reduces the number of separate components needed in the system.
3Reliability
If voltage is increased to recharge electrodes at proper times, then electrode recharging is achieved, but power losses increase
Solution Approach 1:
The system utilizes the periodic stretching and relaxing cycles of the stretchable material to automatically time the charge and discharge of the capacitor electrodes. Each mechanical cycle naturally produces the voltage variations needed for recharging, eliminating the need for external voltage regulation and timing control systems.
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 solution enhances energy conversion efficiency by eliminating the need for external recharging and optimizing power distribution across capacitors, thereby increasing the overall efficiency of energy harvesting from environmental forces like sea waves.
Implementation Method 1
When the sheet is stretched, the surface is increased while at the same time the distance between its opposite surfaces is decreased. As a result, the capacitance between its pair of electrodes increases, and the voltage resulting from the charge on its electrodes decreases.
Implementation Method 2
The SM material functions like a variable capacitor. As a part of the system is moved back and forth, it can be made to repeatedly stretch and relax a quantity (e.g. a sheet) of SM which is preferably EAP (electro active polymer) material.
Data Source
Figure 1~3
Figure 4~5
Figure 6~8
AI summary
An electricity generator having variable capacitors that each includes a repeatedly stretched and relaxed sheet of SM (stretchable material) and electrodes lying against opposite faces of the sheet, which includes a power extraction unit coupled to the electrodes of at least a pair of capacitors. The unit directs an electrical charge (current) from a first pair of electrodes that have a higher voltage, to one or more second pairs of electrodes that have a lower voltage, to recharge the second pairs of electrodes. During the current flow electrical power is extracted by the drop in voltage of current passing through the unit. The power extraction unit can be provided with a control unit that has voltage detectors and that selectively connect capacitors, based on their voltages, for maximum efficiency in generating power output.