Vibration-based automatic power-generation system

Abstract

Two types of electric power generator systems that automatically extract power from oscillating motion of a human body or vibration of machines and structures are proposed and studied. The first system utilizes self-excited rotation of an eccentric rotor that rotates in one direction in synchronization with the applied oscillating motion. Connecting an electrical load to the generator increases the damping about the rotor axis, and numerical analysis shows that there exists an upper limit to this damping to maintain the self-excited rotation mode. Excessive damping reduces the rotor to a swinging motion, resulting in decreased power output. The second type utilizes resonant vibration of a permanent magnet unit suspended by a set of springs. In order to maximize the output power, a micro controller changes the connection of the generator coils, which in effect changes the electro-mechanical damping, to keep the vibration amplitude within the allowable stroke. Theoretical analysis and experimental results are presented for both systems.

Effective optimization of electromagnetic energy harvesters through direct computation of the electromagnetic coupling

“…A clear description can be found in [14][15][16], referring to Faraday's law, in Ref. [17], referring to the Lorentz's force, and in Ref. [18] with the coupling geometrically derived from the change of the flux linkage.…”

Nanomechanics: Fundamentals and Application in NEMS Technology

“…A different system exploits the resonant vibrations of a magnet placed inside a coil and suspended by springs. The power output reaches a maximum when the frequency of the oscillatory motion matches the resonance frequency of the system, which can be adjusted by tuning the mass and the elastic constant of the springs [103].…”

A new energy harvest system with a hula-hoop transformer, micro-generator and interface energy-harvesting circuit

“…Arnold (2007) proposed three types of electromagnetic power generation systems in the range of microwatts to tens of watts. Sasaki et al (2005) proposed a device that is combined with gear train to generate power under the state of self-excited rotation. Spreemann et al (2006) also presented an electricity-generating device with the volume 1.5 cm 3 and power 0.4-3 mW at vibration frequencies of 30-80 Hz.…”