Investigation of a bistable nonlinear hybrid energy harvester (NL-HEH) for wideband applications

This work presents a bistable nonlinear hybrid energy harvester using Piezoelectric (PE) and Electromagnetic (EM) transducers to harvest ambient wideband vibrations. Stretching-induced nonlinearity due to a nonlinear FR4 spring combined with repulsive magnet-induced nonlinearity will introduce bistable nonlinearity into the proposed harvester. This bistable nonlinearity widens the operational bandwidth of the system by 14.3% at 1 g acceleration with respect to a presented nonlinear monostable harvester and linear resonant harvester counterparts. The numerical model of the bistable nonlinear hybrid energy harvester is developed and analyzed for the performance improvement of the vibration energy harvester. With an input excitation of 1 g, the PE and EM transducers generated output power of 0.94 $$\:\mathbf{m}\mathbf{W}$$and 0.3 $$\:\mathbf{m}\mathbf{W}$$, respectively. The total output power and operational bandwidth density of the proposed NL-HEH can reach 1.2 $$\:\mathbf{m}\mathbf{W}$$and 22 Hz, ranging from 143 Hz to 165 Hz. The hybrid design improves the generated output while the nonlinearity in the system widens the operational bandwidth to achieve a relatively high normalized power density of 3.4 $$\:\text{m}\text{W}/{\text{c}\text{m}}^{3}{\text{g}}^{2}$$