Magnetostrictive Power Generation Element Resisting Bending
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Solution Overview
Problem
Existing power generation methods using piezoelectric elements face limitations due to low power generation efficiency when subjected to bending deformation, high impedance at low frequencies, and the need for large amplitude and high-frequency vibrations, while methods using magnetostrictive materials require excessive force and uneven compression, leading to inefficient power generation.
Innovation Solution
A power generation element utilizing two magnetostrictive rods made of materials like Galfenol or permendur, with coils wound around them, that undergo expansion and contraction perpendicular to their axis direction, leveraging the inverse magnetostrictive effect to generate power efficiently with small force and resisting bending and impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If piezoelectric elements are deformed by bending, then power can be generated, but power generation efficiency is low and the material is easily damaged
Solution Approach 1:
The patent changes the deformation mode from bending to longitudinal compression/expansion. The piezoelectric element is configured to undergo compression and expansion in the longitudinal direction (parallel to polarization axis) rather than bending, which significantly improves both power generation efficiency and structural reliability. This parameter change in deformation type resolves the contradiction between power generation capacity and material durability.
Solution Approach 2:
Instead of applying force perpendicular to the polarization axis (bending mode), the patent applies force parallel to the polarization axis (compression/expansion mode). This inversion of the force application direction allows the piezoelectric element to operate in its high-efficiency longitudinal mode while avoiding the structural damage associated with bending, thus resolving the contradiction between power generation and reliability.
2Power
If piezoelectric elements are used, then power can be generated, but impedance is high at low frequencies reducing power output
Solution Approach 1:
The patent changes the operational frequency parameter to resonate at higher frequencies. By designing the piezoelectric element and its mounting structure to resonate at frequencies above 1 kHz, the system operates in a frequency range where the capacitive impedance of the piezoelectric element is lower, enabling more effective power transfer to low-impedance loads and resolving the high impedance problem at low frequencies.
3Power
If magnetostrictive material is compressed to generate power, then current can be induced, but excessive force is required and compression is uneven
Solution Approach 1:
The patent replaces direct mechanical compression of the magnetostrictive material with electromagnetic actuation. A coil generates a time-varying magnetic field that induces alternating magnetization in the magnetostrictive rod, causing it to expand and contract without requiring external mechanical compression forces. This substitution eliminates the need for excessive compressive force while achieving uniform actuation throughout the material.
Solution Approach 2:
The patent changes the actuation mechanism from mechanical compression to electromagnetic induction. By applying an alternating magnetic field through a coil, the magnetostrictive material is actuated through changes in magnetic flux density rather than mechanical force, significantly reducing the required actuation force while maintaining uniform compression/expansion cycles.
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 solution achieves high power generation capacity with strong resistance to bending and impact, efficient power generation at higher resonance frequencies, and increased voltage output, surpassing the limitations of traditional piezoelectric and magnetostrictive methods.
Implementation Method 1
a temporal change in magnetic flux density through a magnetostrictive material which changes magnetic permeability through a reverse magnetostrictive effect by applying force from outside
Implementation Method 2
a method for generating power using a change in magnetic flux of a permanent magnet is a method for generating power by a temporal change in interlinkage magnetic flux density of coil caused by vibration of the permanent magnet
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The present invention provides a power generation element which has strong resistance to bending and impact and has high power generation capacity, and a power generation apparatus including the power generation element. The power generation element (1) includes: a first magnetostrictive rod (11a) made of a magnetostrictive material; a rigid rod (11b) made of a magnetic material and disposed in parallel with the first magnetostrictive rod (11a), the magnetic material having rigidity and a shape that enable uniform application of compression force or tensile force to the first magnetostrictive rod (11a); a first coil (12c) wound around the first magnetostrictive rod (11a); and two connecting yokes (10a and 10b) each of which is provided at one end of each of the first magnetostrictive rod (11a) and the rigid rod (11b) to connect the first magnetostrictive rod (11a) and the rigid rod (11b), wherein the power generation element (1) generates power through expansion or contraction of the first magnetostrictive rod (11a) due to vibration in a direction perpendicular to an axis direction of the first magnetostrictive rod (11a).