A low-frequency wideband vibration harvester based on piecewise linear system

This paper presents a low-frequency wideband electromagnetic vibration energy harvester for scavenging the ambient vibration. The proposed energy harvester is mainly composed of a diamagnetically stabilized levitation structure and elastic films as the stoppers. A levitated magnet moves inside the harvester when it is excited by external horizontal excitation. Elastic film is introduced to build a piecewise linear system which can increase the resonant frequency and extend the operating bandwidth for the energy harvester. A prototype was fabricated and tested by a vibration exciter and hand shaking. It was found that the operating bandwidth reaches 3Hz at excitation amplitude of 5mm. A maximum 152W output power was obtained from the harvester while it is excited under the excitation of 5Hz frequency and 0.8g acceleration. A 12-stage Villard's multiplier circuit was adopted to rectify and boost the output signal of the vibration harvester. Under the hand shaking excitation, the proposed energy harvester can light up a light-emitting diode by the voltage multiplier circuit, demonstrating its potential application for powering some portable and wearable smart devices.