Theoretical Investigation of Bistable Piezoelectric Energy Harvester Using Frequency Down-Conversion

Recently, vibrational energy harvesting has been considered a promising alternative to batteries for powering microsystems for large wireless sensor network applications. However, ambient vibrations are below 100 Hz, while most machines and equipment operate relatively at high frequencies (more than 70 Hz). Herein, we propose a theoretical study to harvest energy from high frequencies using a frequency-down bistable piezoelectric energy harvester mechanism. We investigate the energy harvesting benefit in the down-conversion of a high-frequency signal to a low-frequency signal utilizing magnetic coupling. A high-frequency driving beam triggers a low-frequency generating beam. We use a spring-mass-damper equivalent model to understand the operation mechanism of the proposed piezoelectric vibration energy harvester. Based on the theoretical model, the static and dynamic effect of magnetic nonlinearity on the performance of the proposed piezoelectric vibration energy harvester is numerically analyzed. The targeted applications are the down-conversion and the filtering of high frequencies and mass sensing, particularly the harvester's behavior for mass sensing applications.