A study on important issues for estimating the effectiveness of the proposed piezoelectric energy harvesters under volume constraints

Abstract

This study presents theoretical investigations on the effectiveness criteria for piezoelectric energy harvesters (PEHs) under volume constraints. Firstly, the importance of the volume consideration is investigated. The powers of different PEHs of variant volumes are investigated under the same resonance frequency. It is found that the power output is strongly dependent on the volume of the transducer. Secondly, the impact of the mechanical damping, the electrical damping, the volume of motion, the normalized power to the volume, and the applied load resistance on the power output are investigated. The investigations are analyzed to find the optimized conditions of the applied load and the excitation frequency in order to optimize the power output under volume constraints. The proposed procedure for estimating the effectiveness is to compare the performance of the proposed PEHs to a rectangular-shaped PEH of the same volume. An optimized structure for a rectangular-shaped PEH to be used as the reference is investigated. The power output under the optimized conditions is derived. In order to estimate the effectiveness of the proposed PEHs, the average power over a band of frequencies from the proposed structure must be compared to the average power over the same band of frequencies from the optimized reference harvester.