The effect of magnetic proof masses on the energy harvesting bandwidth of piezoelectric coupled cantilever array

In order to explore the ability of magnetic force in improving energy harvesting bandwidth, a novel energy harvester of piezoelectric coupled cantilever array (PCCA) was proposed which introduces nonlinear magnetic force (damping) to differentiate the natural frequencies of PCCs and widen energy harvesting bandwidth of PCCA. Meanwhile, the design of PCCA can increase the number of voltage peaks of each PCC at the cost of decreasing the voltage peaks of its neighbouring PCCs at resonance. The effect of some significant factors, such as PCC interval, PCS length, PCC number, and PCC substrate thickness, on PCC voltage, PCC natural frequency, and PCCA bandwidth are deeply studied and analyzed by experiments and simulations. The results demonstrate that the bandwidth for the proposed PCCA can achieve 73 Hz by the standard of >15 V pp. voltage in the excitation of 1 g acceleration amplitude. Based on the experiment and simulation results, a series of theoretical models are derived to compute PCC voltage, PCC natural frequency, and bandwidth of PCCA with different design parameters, these theoretical models give a reliable instruction for the design of PCCAs to match environmental vibration with different frequency such as machine, wind, wave, and so on.