Research of Non-linear Oscillator Interfaces in Piezoelectric Energy Harvesting
Date Issued
2011
Date
2011
Author(s)
Chang, Yen-Cheng
Abstract
It has been shown that optimum power output of a linear piezoelectric energy harvester occurs when the driving frequency is close to the resonance of the device. However, the vibration sources typically have a wide range of frequency bands. This motivates us developing nonlinear piezoelectric oscillators for vibration energy harvesting.
The nonlinear oscillator is constructed by introducing magnetic couplings on the cantilever beam. As a result, the stiffness of the structure varies depending on the strength of magnetic couplings. The governing equations are derived assuming a suitable form of magnetic potential energy, and their solutions are numerically solved and validated by experiment.
The result shows that the magnitudes of harvested power depend on the relative strength of magnetic couplings. At small coupling, the potential energy has a single well, while it exhibits double wells under large magnetic coupling. As a result, the optimal harvested power occurs at the transition from a single well structure to the double well structure. In addition, it is observed that harvested power is enhanced significantly and exhibits wideband effect in a nonlinear system under either harmonic or random excitation.
Subjects
Piezoelectric Materials
Non-linear Oscillator
Wideband Effect
Type
thesis
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