Equivalent Circuit Model for MEMS Vibrational Energy Harvester Compatible with Sinusoidal and Nonsinusoidal Vibrations

Abstract

We build an equivalent Simulation Program with Integrated Circuit Emphasis (SPICE) model for a vibrational energy harvester comprising comb electrodes coated with an electret film that is used to convert the vibrational kinetic energy into electrical output power by electrostatic induction. In the assembled module, sinusoidal and nonsinusoidal vibrations are imported into the nonlinear current sources as an inertial force, and the power-generating performances are simulated. The nonsinusoidal waves observed in an actual environment (highway duct) are used as an input sample. By quantitatively comparing the simulation and experimental results, we verify the applicability of the equivalent module for various vibrations. When the device is excited by sinusoidal vibration, the maximum output power is calculated to be 71 µW at 0.044 G (1 G = 9.8 m/s 2), which is close to the experimental result of the actual device, 68 µW at 0.045 G. Furthermore, when importing a nonsinusoidal vibration, the two timings at the highest generating peak are obtained in accordance with the moment of resonance, and the amplitudes are experimentally and analytically obtained to be 0.80 and 0.63 V, respectively.

Power enhancement of MEMS vibrational electrostatic energy harvester by stray capacitance reduction

“…To verify the effect of the BOX layer thickness and the height of the comb structures, the dynamic behaviors of energy harvester are numerically simulated using the SPICE equivalent circuit model reported elsewhere [43].…”

MEMS Electrostatic Energy Harvester Developed by Simultaneous Process for Anodic Bonding and Electret Charging

“…Most environmental vibrations are seen in the acceleration range of 1 G (G = 9.8 m/s 2 ) or smaller, (5,6) and they can be converted into electrical power using a carefully designed MEMS-based energy conversion mechanism such as the piezoelectric effect, (7)(8)(9)(10)(11) electromagnetic induction, (12)(13)(14)(15)(16) and electrostatic induction. (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) Amongst them, electrostatic energy harvesters using the permanent electrical charge or socalled electret can effectively convert small mechanical vibrations into electrical power, owing to the advantage that the mechanical resonator part and power-generating electrodes can be independently designed to optimize the harvester performance as a velocity-damped resonance generator (VDRG). (33) Figure 1(a) shows a photograph of an electret-type vibrational energy harvester reported elsewhere.…”