反磁性体による低損失磁気浮上共振系を用いた振動発電

抄録

In this paper, a low-frequency mechanical resonator based on diamagnetic magnetic levitation is investigated. This resonator is advantageous for the use in a vibration energy harvester because of its magnetically-sprung design without any mechanical contact. However, as a drawback, there exists a considerable damping due to the eddy current loss in the diamagnetic material because it acts as a conductor. In this study, reduction of the eddy-current loss is achieved by electrically dividing the diamagnetic plate into small pieces to suppress the eddy-current induction so that the damping ratio of the resonator becomes under 0.01. More specifically, comparison is made for a continuous diamagnetic plate, a plate divided into10 pieces in parallel with the moving direction, a plate divided into 10 pieces vertical to the moving direction, and a plate divided into 100 grid pieces. Theoretical calculation and experimental results showed that the division of the diamagnetic plate into 10 pieces vertical to the moving direction or 100 grid pieces can reduce the damping ratio under 0.01.