Wideband Low-Frequency Piezoelectric Energy Harvester with Two Concentrated Proof Masses

Harvesting the wasted vibrations in the surroundings and converting these vibrations to voltage difference through the piezoelectric (PZT) effect, is a promising approach to power many industrial and medical sensor networks. Ambient vibrations often exist in a wideband frequency form, so it is recommended to propose a simple design that can operate in broadband natural frequency of ambient vibration. This paper presents a two-degree-of-freedom (2-DOF) of a piezoelectric cantilever with two concentrated masses. The proposed design provides a broadband natural frequency (1–41 Hz) with high performance. The investigation is conducted using the Finite Element Method (FEM) using COMSOL Multiphysics. 2DOF Lumped mass system of the proposed harvester is derived for verification purposes. The effect of two concentrated masses on the natural frequency range is investigated. The resistance and piezoelectric thickness effects on output power are presented. It is found that the optimum power density at the optimal electric resistance is 0.037 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$({\mu}\mathbf{W}/\mathbf{mm}^{\mathbf{3}})$</tex> .