New energy harvester with embedded piezoelectric stacks

Abstract

Mechanical energy harvesters are designed to capture the ambient energy and transform it into usable electrical energy. Power harvesting from mechanical vibrations is the fundamental step toward providing self-powered smart systems in the developing wireless and portable electronic devices marketplace. This paper presents a new design and an analytical model for the development of a composite energy harvester by using piezoelectric stacks. The in-plane polarization of the piezoelectric elements and the flexible electrode design using piezoelectric stacks are introduced to maximize the electrical voltage/charge output. The presented model is applicable to composite beams with structural strain rate damping and embedded piezoelectric stacks. The steady state vibration response of the composite harvester subjected to a harmonic base motion is obtained and electrical outputs are analytically derived. Moreover, a parametric study for the composite energy harvester with different embedded piezoelectric stacks number, length and thickness under the excitation in a wide frequency domain has been done. Finally, the new design is compared to a conventional unimorph harvester with identical geometrical and material properties to demonstrate the potential significant improvement in the electrical charge and voltage outputs.