Vibrated model and experiments of multiple piezoelectric cantilevers in energy harvesting

A single piezoelectric cantilever is sensitive to the vibration frequency for scavenging ambient energy. The efficiency of the piezoelectric cantilever is very low when the resonance frequency does not match the environmental vibration frequency. In order to increase the frequency band of the piezoelectric cantilever, multiple piezoelectric cantilevers (MPECS) are designed. A vibration model is presented to determine the resonance frequency of MPECS. It can be found that the results obtained from the theoretical model are basically in agreement with the experimental results. Comparing with a piezoelectric cantilever, the MPECS can effectively increase the band of resonance frequency. The generating capacity of MPECS power generation unit is tested. The maximum output power can reach 4.9 mW at a load of 820 Ω and a working frequency of 60 Hz. The generated energy can satisfy the demand of low-energy microelectronic products such as network sensors.