Dynamic modeling and experimental validation of a low frequency piezoelectric vibration energy harvester via secondary excitation of pressured fluid

Abstract

A low frequency piezoelectric energy harvester using secondary excitation of pressured fluid is proposed in this paper to scavenge low frequency vibration energy in ambient environments. This harvester was characterized by an indirect vibration-to-electric energy converter via transferring the pressure energy of pressured liquid medium. A series of simulations and experiments were conducted to prove the good performance and the feasibility of this novel structure in low-frequency high-intensity vibration. The results showed that the diameter of damping orifice, initial system backpressure and proof mass brought strong influences on the resonance frequency and output voltage. Meanwhile, according to experiments, it was found that the resonance frequency was decreased with the decreasing liquid backpressure. In this case, lowest resonance frequency of 19 Hz was achieved under the condition of 10-kg proof mass and 0.2-MPa liquid backpressure. Also, there were the optimal proof mass and backpressure to maximize the generated voltage, respectively. Moreover, in the impedance matching experiments, the maximum output power reached 1.35mW at the matching load resistance of 18kΩ.