3D Vibration Harvesting Using Free Moving Ball PZT Microbox

A novel approach to PZT energy harvesting is proposed. Through an experimentally confirmed simulation, the new design was shown to offer a much wider range of resonant frequencies, namely below 100Hz, and a much more isotropic behavior than cantilever structures; although when exposed to 5たm vibration at 100Hz, the power density was evaluated to 50nW.cm -3 for a 2.1mm unit, and to 18nW.cm -3 when scaled down to 0.01mm. The resonant behavior of the system was also identified and linked to the relative backlash of the rigid ball encapsulated in the structure comparatively to the excitation amplitude. Finally, design optimization is discussed.