Science Daily November 29, 2022
Vibration energy harvesters suffer from a significant drop in performance for non-steady-state vibrations, which are important for practical applications. Researchers in Japan demonstrated that the output power under an impulsive force can be increased significantly by placing a U-shaped metal component, called a dynamic magnifier (DM), under a MEMS piezoelectric vibration energy harvester (MEMS-pVEH) with a Pb(Zr,Ti)O3 film. Based on the results of numerical calculations they designed DM to have the same resonant frequency as the MEMS-pVEH and a high mechanical quality factor (). They measured the waveforms of the output voltage of the fabricated 2DOF-pVEHs for impulsive forces with various duration times. The output power of the MEMS-pVEH placed on the DM showed a gradual change according to the duration of applying an impulsive force and a maximum of 19 nJ/G2 when the duration of the impulsive force was 3.8 ms. This result was about 90 times greater than the output power of the MEMS-pVEH without a DM. According to the researchers the fabrication of pVEHs with a complex 2DOF structure can be significantly improved by adding a spring structure to a simple MEMS-pVEH…read more. TECHNICAL ARTICLE