Vibration Characteristics and Experimental Research of an Improved Bistable Piezoelectric Energy Harvester

Featured Application In this paper, an improved bistable piezoelectric energy harvester (IBPEH) suitable for a vibration environment is studied. It can replace polluting batteries to supply power for low-power sensors. The linear-arch composite beam in this paper solves the defect that the traditional piezoelectric energy trap can only collect vibration energy in a single direction and further enhances the collection efficiency of the bistable piezoelectric energy harvester by optimizing the potential well. The energy harvest proposed in this paper provides an application for the intelligent development of dangerous places such as coal mines. Bistable piezoelectric energy harvester (BPEH) can remove mechanical energy waste, which is expected to realize the self-power supply of wireless sensors. To further improve the energy harvesting efficiency, we designed an improved bistable piezoelectric energy harvester (IBPEH). The restoring force model of the composing beam is acquired based on fitting experimental data, and the nonlinear magnetic model is obtained by using the magnetic dipole method. The electromechanical coupling dynamics model of the system is established based on Newton's second law and Kirchhoff's law. Based on the control variable method, the influences of excitation frequency and excitation amplitude on the vibration characteristics of IBPEH and BPEH are compared in simulation analysis. Moreover, the correctness of the theoretical analyses is verified by experiments. The results show that variations in the number of magnets and appropriate adjustments in their positions can broaden the operating frequency bandwidth of the bistable piezoelectric energy harvester, and realize large-amplitude periodic motion at lower excitation amplitudes. IBPEH can yield a higher voltage than BPEH under the same excitation conditions. This paper provides a theoretical basis for optimizing the potential well and further improving the electric energy harvest efficiency of the bistable piezoelectric energy harvester device.