電池フリーIoTの実現に向けた磁歪式振動発電デバイスの量産構造の提案

抄録

　Author proposes mass production structure of magnetostrictive vibrational power generator for battery- free IoT. This is based on a lamination of Fe-Ga alloy and a magnetic material (part), with a coil wound. This lamination is formed as a part of a U-shaped frame yoke with a permanent magnet attached. The magnetic part has moderate rigidity and is in a state of magnetic saturation. When the lamination is bent by an external force, the uniform stress generated in Fe-Ga changes the magnetic flux due to the Inverse magnetostrictive effect, and electromotive force proportional to time differential of the interlinking magnetic flux is generated in the coil. Compared with our conventional parallel beam type, the number of turns of the coil can be increased more than twice, and the assembly is easy and durability is high. The prototype using a Fe-Ga plate of 4 x 0.5 x 16mm³ generated maximum power of 1 mW at 28.4 Hz and 0.075 G vibration, and succeeded wireless signal transmission with one free vibration.