振動発電デバイスの自由度拡張と実環境振動を考慮した最適設計

抄録

Expanding degrees of freedom in vibration systems is an effective way to improve the power generation efficiency of energy-harvesting devices from the vibrating source, since the system becomes responsive for a wide frequency range due to the appearance of multiple resonant peaks. A magnetostrictive-type vibration energy harvester that uses an irongallium alloy (Galfenol) has received much attention in recent years. This energy harvesting technology has advantages over conventional types with respect to the compactness and efficiency, and it is extremely robust and has low electrical impedance. In this study, the differential evolution (DE), known as a kind of global optimization techniques, was introduced for the parameter design of the harvester that comprised a primary structure with an extended two-degrees-offreedom substructure connected to the end. Using DE, we numerically explored the best combination of the mass and dimension of the extended part that minimized the difference between the dominant frequency components in ambient vibration and the natural frequencies of the generator. The proposed design was found to improve the device's electric power generation efficiency.