Enhanced broadband piezoelectric energy harvesting using rotatable magnets

Abstract

We investigate a magnetically coupled nonlinear piezoelectric energy harvester by altering the angular orientation of its external magnets for enhanced broadband frequency response. Electromechanical equations describing the nonlinear dynamic behavior include an experimentally identified polynomial for the transverse magnetic force that depends on magnet angle. Up-and down-sweep harmonic excitation tests are performed at constant acceleration over the range of 0-25 Hz. Very good agreement is observed between the numerical and experimental open-circuit voltage output frequency response curves. The nonlinear energy harvester proposed in this work can cover the broad low-frequency range of 4-22 Hz by changing the magnet orientation.

Nonlinear dynamic and energetic characteristics of piezoelectric energy harvester with two rotatable external magnets

“…The field equations of the beam and magnetic force are sophisticatedly derived using the modified Hamilton's principle and magnetic current model, respectively. The derived equations are qualitatively validated by comparison with the experimental results reported in Zhou et al (2013) [31] and by conducting experiments, it is shown that the mathematical model can predict large-amplitude motion well. The linear terms of the magnetic force and torque are properly reflected in deriving the accurate eigen-modes, and the field equation of the cantilever beam coupled with the electronic circuit is discretized into a single mode oscillator using the Galerkin method.…”

Structure–performance relationships for cantilever-type piezoelectric energy harvesters

“…Among piezoelectric harvesters, a cantilever-type bending structure has been most frequently investigated. [9][10][11][12][13][14] The performance of a piezoelectric energy harvester has often been reported in terms of power density (output power per harvester volume, unit: W cm À3 ) measured at a given frequency and acceleration of vibration. The reported power density values for piezoelectric energy harvesters range from lW cm À3 to a few mW cm…”

A piezoelectric energy harvester based on internal resonance

“…Zhu and Zu [12] presented a buckled-beam piezoelectric energy harvester that uses a midpoint magnetic force to improve the efficiency of output voltage. Zhao et al [13] reported numerical and experimental investigations of a bistable piezomagnetoelastic energy harvester using rotatable magnets. Arrieta et al [14] proposed a novel piezoelectric energy harvester of bistable plate and studied the output voltage and power by experiments.…”