Simulation and characterization of symmetrical planar spring FR4-based for Electrodynamic Vibration Energy Harvesting

This paper discusses about vibration energy harvesting using electrodynamic method, where inertial mass (a magnet) moves relative to an idle conductor. An thin planar spring with material of FR4 is used as mechanical spring, an NdFeB magnet is used as an inertial mass, and bobbin-less coil is used as the conductor. The research discussed in this paper compares the maximum voltage and resonance frequency generated by the Electrodynamic Vibration Energy Harvesting (EVEH) device with an FR4 thin planar spring with the dimensio n of 25mm × 25mm, one of which uses two 14mm symmetrical cantilever arm, and the other uses four 7mm symmetrical cantilever arm. Finite Element Analysis (FEA) Comsol 4.3a simulation software is used to design the mechanical spring and EVEH device. Fabrication of the mechanical spring is done using laser cutting method and EVEH device characterization is done using a loudspeaker as vibration energy source. From the experiment, it is found that the two symmetrical cantilever EVEH generated a maximum voltage and resonance frequency of respectively 303 mV and 45 Hz with 0,5g acceleration then 423 mV and 49 Hz with 1g, while the four symmetrical cantilever EVEH generated 235 mV and 102 Hz with 0,5g then 350 mV and 113 Hz with 1g, where g = 9,8 m/s².