Modeling and verification of a piezoelectric frequency-up-conversion energy harvesting system

An impact-based frequency-up-conversion (FUC) energy harvesting system has been studied for realizing high power density from ambient vibration. It can harvest the lower frequency environment vibration and convert into a higher frequency self-oscillation. The energy output is greatly improved. In this paper, theoretical modeling of the FUC energy harvesting system is established, including a lower frequency piezoelectric bimorph (LFPB) and a higher frequency piezoelectric bimorph (HFPB). The dynamic analysis is carried out and the output performance is simulated. Experiments indicate that the developed FUC system can generate a high peak power of 2.62 mW and an average power of 0.58 mW from an external excitation acceleration of 1 g at 29 Hz. The peak power output of the HFPB operating at 153.8 Hz is about 4.5 times higher than that of the LFPB at 29 Hz. This work provides a theoretical basis and methodology for developing impact-based FUC energy harvesting system, which opens up a way for achieving high power output at low ambient frequency.