A Frequency Up-Converted Piezoelectric Energy Harvesting System with Broad Bandwidth Based on MEMS PZT Thick Film Technology

In this paper, an impact-based frequency up-converted piezoelectric energy harvesting system (PEHS) is proposed and fabricated using MEMS piezoelectric thick film technology. The PEHS mainly consists of a high-frequency piezoelectric cantilever (PC-H) with resonate frequency of 935 Hz and a low-frequency stainless-steel cantilever (SC-L) with resonate frequency of 23 Hz. Under the external low-frequency vibration excitation, the SC-L at the bottom impacts the PC-H during the movement, in this way the low-frequency external vibration is converted to high-frequency piezoelectric cantilever vibration. When the PC-H is triggered to vibrate at 935 Hz, the maximum voltage output is 74 mV at 1.0 g. Then incorporate the PC-H with SC-L and form the PEHS, at driving frequency of 20 Hz to 34 Hz, the maximum voltage output and 3dB bandwidth of the PEHS reach 1220 mV and 4.7 Hz, respectively. The maximum voltage output of the PEHS (1220 mV) is more than 16 times of that of the single PC-H (74 mV).