improving the efficiency of a cantilever energy scavenger

Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. recently, efforts have been made to improve the performance of energy harvesters. the output voltage dramatically depends on the geometrical and physical parameters of these devices. in addition, improved performance is often achieved by operating at or near the resonance point. so, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. for this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. these parameters include the length, thickness, density, and young’s modulus of each layer. the beam is considered a unimorph cantilever with rectangular configuration and the study is performed using comsol multiphysics software. the results are compared with those obtained by an analytical approach. the results show that changing the parameters made the natural frequency of the system vary in the range of 20 hz to 200 hz and increased the output voltage up to 20 v.