Promote performance of vibration energy harvesting by amplified inertial force and clamped piezoelectric beams

In this study, a novel vibration energy harvester is proposed, in which the amplified inertial force of a mass acts on two clamped piezoelectric beams to make them execute large-amplitude vibrations densely and produce large outputs. The harvester is composed of an inertial mass, two linkages and two clamped beams. Under excitation, the inertial force generated by the mass can be amplified by the linkages and make the clamped beams deflect easily. Especially, the beam will deflect four times in a cycle, thus it can produce the pulse voltage densely. The theoretical model is established and corresponding simulations are carried out. The validation experiment was conducted. For a low-frequency excitation, the piezoelectric beam can be driven to oscillate with many super-harmonic components, this can increase the electric output in a period. The random experiments prove that the harvester could produce a fairly large output under weak excitation. For the excitation of PSD = 0.06 g²/Hz, it can generate a root-mean-square power of 0.115 mW through a PZT layer of 25 mm × 10 mm.