Performance of Fe–Ga alloy rotational vibration energy harvester with centrifugal softening

Abstract

With the development of vibration energy harvesting, sensor nodes for wireless monitoring are being increasingly powered by harvesting vibrations in rotating environments such as car tires and fan blades. Considering the diverse installation positions of vibration energy harvesters on rotating carriers, the centrifugal forces of the cantilever beams exhibit remarkable differences during rotation. Crucial factors for the performance of vibration energy harvesting include the deformation of the harvester cantilever beam, which is affected by the centrifugal force, and the influence of the pre-magnetization field on the Villari effect of specific alloys. We propose a rotational vibration energy harvester based on an Fe–Ga alloy and establish a mathematical model for magnetostrictive vibration energy harvesting by leveraging centrifugal softening. In addition, we perform a systematic theoretical analysis of the factors influencing the harvester performance considering centrifugal softening, rotation radius, and arrangement of the pre-magnetization field. The theoretical findings are verified on a prototype, and the system characteristics are investigated experimentally. The maximum output voltage reaches 3.36 V, and the energy harvesting efficiency reaches 22.86% when the harvester undergoes rotation at 330 r min−1. Moreover, the harvester is applied in a low-power temperature sensor for real-time temperature monitoring, indicating the validity and applicability of the proposed rotational vibration energy harvester. The results demonstrate that an appropriate use of the centrifugal softening and the pre-magnetization field can enhance the energy harvesting efficiency of a harvester operating at a low rotational frequency.