Design of high output broadband piezoelectric energy harvester with double tapered cavity beam

Abstract

Design of piezoelectric energy harvester for a wide operating frequency range is a challenging problem and is currently being investigated by many researchers. Widening the operating frequency is required, as the energy is harvested from ambient source of vibration which consists of spectrum of frequency. This paper presents a technique to increase the operating frequency range and to enhance the amplitude of the generated voltage in the operating frequency range. The wider operating frequency range is achieved by designing a harvester using propped cantilever beam with variable overhang and the amplitude of the generated voltage is enhanced by introducing a double tapered cavity. The proposed piezoelectric energy harvester is modeled analytically using Euler Bernoulli beam theory. The results from the modeling and analysis reveal that the maximum voltage is generated from the energy harvester designed with the double tapered cavity having the taper angle of α = 2.25°. Hence the experimental investigations are carried out with this energy harvester and the generated voltage measured is in close agreement with the results obtained from the model. The simulation and experimental results presented in this paper demonstrate that the proposed harvester design not only widens the operating frequency range but also it enhances the amplitude of the generated voltage in large extent.