Nonlinear multimodal energy harvesting system: A dual-cantilever beam structure for combining piezoelectric and electromagnetic mechanisms

A nonlinear piezoelectric-electromagnetic composite energy harvester (NEPH) is proposed. The dynamic equations of its electromechanical system are established and numerical methods are used to simulate its voltage output characteristics if the system parameters are changed. The experimental setup is built up to measure the output characteristics of the prototype. Experimental results show at the first resonant frequency (22 Hz), the total power of the PH generator under a load impedance of 50 kΩ is 5.51 mW, and the total power of the EH generator under a load impedance of 200 Ω is 72.48 μW; at the second resonant frequency (30 Hz), the total power of the PH generator under load impedance of 50 kΩ is 1.79 mW, and the total power of the EH generator under load impedance of 200 Ω is 27.42 μW. In addition, the two electromagnetic generators have the same amplitude, frequency, and phase, so they can be directly connected in series or parallel without rectification. Finally, a practical application in driving electronic loads proves the potential value in supplying power to some low-power electronic devices.