Experimental study of a hybrid vibration energy harvesting mechanism

In this paper, a novel hybrid vibration energy harvesting mechanism integrating effects of both electromagnetic induction and piezoelectricity have been presented. The structure topologically consists of three modules. The first is electromagnetic induction module comprising of two pairs of bulk NdFeB permanent magnet and one hand-wound enameled copper coil. The second is piezoelectric energy harvesting module utilizing impact mode. The last is another piezoelectric energy harvesting module based on impact-induced vibration. Mounting a manufactured prototype of the proposed generator onto an electric shaker, preliminary experimental tests have been performed; electric energy stored in capacitor via bridge rectifier was measured and analyzed. It was found that, in 30 seconds, the harvested electric energy was 57.2 μJ for impacted piezoelectric components, 429.3 μJ for piezoelectric components under impact-induced vibration and 6547.2 μJ for the electromagnetic induction component, respectively, at the vibration excitation amplitude of 4.5 mm and frequency of 13 Hz.