Analysis and characterisation of a cantilever energy harvester

Abstract

Harvesting the energy from base vibration through a Piezo-electric Transducer (PZT) is an adaptable and an emerging technique in recent years. The power output of piezoelectric energy harvester can be improved by an appropriate configuration of its geometry and positioning of additional mass. This paper presents a numerical study on a cantilever energy harvester to quantify the energy harvested from vibration having a single frequency harmonic excitation and discusses the effect of base acceleration on the energy output for different beam widths and proof masses. It focusses on the numerical simulation procedure necessary to develop a deeper understanding on the performance of the harvester. The methodology adopted to finalise the geometry and the proof mass is explained. The configuration of the cantilever energy harvesting structure includes structural steel cantilever beam sandwiched between two PZT layers. The beam is subjected to harmonic excitation. The results suggest that the bimorph configuration produces more energy output when the ratio of length to width of beam is more with large proof mass, provided the induced stress in the piezoelectric material is within the permissible limits. The studies demonstrated that the finalised harvester can deliver a maximum of 880mW of power to a matched resistive load of 12kΩ, when exposed to a base acceleration of 30g at the resonant frequency of 77.5Hz.