Simulation and Characterisation of Planar Spring Based on PCB-FR4 in Electromechanical System for Energy Harvesting

Abstract

This paper presents comparison study of simulation and fabrication characterized two type planar springs at micro–fabricated electromagnetic power generator for an ambient vibration energy harvesting system. The power generator utilized a LASER–machined FR4-PCB planar spring, a copper coil, and NdFeB magnet. In order to change resonant frequency, we developed a gimbal suspension structure for the fabrication of spring. The NdFeB permanent magnet was applied as inertial mass. The system was specially designed to harvest low ambient vibrations from 20 to several hundred hertz and low acceleration. The dimension of fabricated energy harvester had 2.5 x 2.5 cm2 in size. In this study we present two different design of cantilever, which is has two and four cantilever, respectively. The different designed given different resonance frequency to the system. The result of simulation giving resonance frequency of two cantilever membrane 22.6 Hz and four cantilever membrane 110.3 Hz. The measurements result has generated 0.135 V with resonance frequency 39 Hz of two cantilever membrane appropriate for human motions, four cantilever membrane has generated 0.174 V with resonance frequency106 Hz appropriate for machine industries.