Equivalent circuit modeling and experimental validation of a piezoelectric energy harvester attached on a thin plate with AC-DC conversion

Abstract

Plate-like structures are widely used in numerous automotive, marine and aerospace applications. Power output investigations of patch-based piezoelectric energy harvesters integrated to these structures require accurate models for energy harvesting performance evaluation and optimization. The equivalent circuit modeling of the cantilever-based vibration energy harvesters for estimation of electrical response has been proposed in the recent years for predicting the electrical outputs of the harvesters. However, equivalent circuit modeling of piezoelectric patch harvesters integrated to plate-like structures including nonlinear circuits has not been studied in the existing literature. Considering these needs, a multi-mode equivalent circuit model of a piezoelectric energy harvester integrated to a thin plate is developed and verified experimentally in the present study. Equivalent circuit parameters are obtained from analytical distributed-parameter model of the plate and harvester which governs the electromechanical coupling behavior of piezoelectric patch and vibration of the host plate. The multi-mode circuit representation of the harvester is built via electronic circuit simulation software SPICE. Using the SPICE software, electrical outputs of the piezoelectric energy harvester are computed for the standard AC input-AC output and AC input-DC output problems. In the AC-AC case, only a resistive load is connected to the harvester, whereas for the AC-DC case, a full-wave rectifier and a smoothing capacitor are connected to the circuit before the resistive load to convert the AC voltage to stable DC voltage. In the AC-AC problem, voltage FRFs are calculated for various resistive loads and validated by the published analytical closed-form solution. In the AC-DC problem, simulation results of the DC voltage and power outputs are computed for a wide range of load resistance values and validated with comparisons against the analytical single-mode representation of the harvester. Finally, experimental measurements of DC voltage FRFs are conducted for a case study and verified against the numerical model.