Design and verification of an inertial anti-phase hybrid vibration energy harvesting system

Harnessing and converting environmental vibration energy into electrical energy is considered to be a promising solution to achieving self-powered sensor nodes in sensor networks. To improve the efficiency of environmental vibration energy harvesting, a novel hybrid anti-phase energy harvesting mechanism is proposed. The proposed cross-shaped anti-phase harvester consists of a cross-shaped beam with two fixed ends and two free ends, each incorporating an iron core coil, a cantilever beam with magnets, and a piezoelectric patch attached at the center of the cross-beam. Under external excitations, the motion between the iron core coil and the magnets exhibits anti-phase or large relative displacement, which effectively enhances the electrical energy output of the structure. The designed cross-shaped anti-phase harvester shows anti-phase motion between the coil and magnets in multiple modes. Experimental validation studies have been carried out, the results demonstrate that under weak random excitations, the harvester can achieve high power and voltage outputs. At an excitation with power spectral density (PSD) of 0.035 g2 /Hz, i.e. a root mean square (RMS) acceleration of 0.7 g, the RMS power output can exceed 5.153 mW.