Broadband Low-Frequency Vibration Energy Harvester with a Rolling Mass

Abstract

Richness of broadband low-frequency vibration energy in environemnts makes it significant to develop broadband low-frequency vibration energy harvesters. A vibration energy harvester composed of two symmetrical cantilevered piezoelectric bimorphs and a rolling mass in a guiding channel was proposed. A prototype of the vibration energy harvester with a rolling mass was assembled and tested. The base excitation caused the rolling mass to impact with two cantilevered bimorphs repeatedly and the impacts cause the bimorphs to vibrate dramatically. Experimental results show that maximum output power and corresponding excitation frequency increased with the amplitude of base acceleration. For the prototype, the maximum output power of a piezoelectric bimorph on a resistor with the resistance of 100 kΩ was 602 μW under base acceleration with the amplitude of 1.5 g and frequency of 37 Hz, and the half power bandwidth was about 13.5% or 5 Hz.