Electromagnetic Vibration Energy Harvester with Magnetic Springs for Broadband and Frequency Up-conversion

Abstract

Capturing vibration energy from the environment by vibration energy harvesters (VEHs) to power electronic devices such as wireless sensor nodes has become a hot research topic. However, the narrow bandwidth of linear VEHs and the low excitation frequency results in low output power in the actual environmental vibration featuring multiple frequencies. To overcome this limit, this paper proposes an electromagnetic VEH utilizing dual magnetic springs for both broadband and frequency up-conversion. Under the excitation with low acceleration, the cylindrical magnet and the ring one reciprocate synchronously and their corresponding nonlinear magnetic springs help broadband. When the excitation acceleration exceeds a certain threshold, the cylindrical magnet separates from ring one and their interacted magnetic pull realizes the cylindrical magnet’s frequency up-conversion. Firstly, the versatile VEH utilizing nonlinear magnetic spring is compared with that using linear mechanical spring by simulation analysis and the results show that the former mechanism is superior to the latter one. Afterward, the broadband of the proposed architecture under the excitation of small acceleration is validated by simulation.