A piezohydraulic vibration isolator used for energy harvesting

Abstract

A novel piezohydraulic vibration isolator consisting of a hydraulic cylinder and piezodiscs was presented for low-frequency and wide-bandwidth vibration energy harvesting. The analytical model for performance evaluation was established first based on the theory of vibration analysis and simulated to obtain the influence of backpressure and proof mass on equivalent bulk modulus and stiffness of fluid, and optimal frequency and generated voltage of the piezohydraulic vibration isolator. And then, a prototype was fabricated and tested. The research results show that, under other parameters given, the energy generation performance of a piezohydraulic vibration isolator can be tuned with changing backpressure and proof mass. And there are a series of optimal parameter combinations of backpressure and proof mass for a piezohydraulic vibration isolator to achieve the same optimal frequency and almost the same voltage. The minimal optimal tested frequency of 13 Hz and the relative voltage of 81.6 V were obtained at 0.2 MPa and 10 kg. For parameter combinations (0.4 MPa/10 kg, 0.4 MPa/5 kg and 0.8 MPa/5 kg), the optimal frequency and generated voltage are 19 Hz/98 V, 27 Hz/96.8 V and 39 Hz/94.8 V, respectively. Correspondingly, the bandwidths to generate voltage of 40 V are 28/35/30 Hz, respectively.