PROJECT TITLE :

Combined Effect of Bistability and Mechanical Impact on the Performance of a Nonlinear Electromagnetic Vibration Energy Harvester

ABSTRACT:

This paper presents the look, modeling, fabrication, and characterization of a nonlinear bistable electromagnetic vibrational energy harvesting device. A folded cantilever structure based on low Young's modulus FR4 material reduces the operating frequency, whereas keeping the device footprint comparatively little. The bistability is introduced into the system by a pair of repulsively oriented NdFeB permanent magnets. A second nonlinear mechanism, i.e., mechanical impact between the oscillator and the bottom, is additionally taken into consideration. Analytical expressions are derived to get the restoring force and potential energy for such a system. The model was more numerically simulated and validated with experimental results of the fabricated device. The device generated most power of nineteen.3 μW at 1.five-g acceleration across an optimum resistive load of 1 kΩ, which was more improved by almost 70p.c with an optimized prototype. Both the numerical simulation and experimental results show broadening of the operational frequency range of the nonlinear bistable device by up to four.thirty five Hz at 0.6-g acceleration with respect to the linear counterpart. At higher input vibration, the harvester oscillates with massive amplitude and collides with the bottom, that abruptly changes the system dynamics. At an acceleration of 1.five g, this impact induced change in dynamics increases the peak power frequency and widens the bandwidth even any up to eight Hz (twenty twop.c of the height power frequency). Thus, the consequences of both bistability and mechanical impact are incorporated into a single device to get a fairly wideband operation.