Papers by Author: Jing Quan Liu

Abstract: As the low-power wireless sensor components and the development of micro electromechanical systems, long-term supply of components is a major obstacle of their development. One of solutions to this problem is based on the environmental energy collection of piezoelectric vibration energy harvesting. Currently, frequency band of piezoelectric vibration energy harvester is narrow and the frequency is high, which is not fit for the vibration energy acquisition in the natural environment. A piezoelectric vibration energy harvester with lower working frequency and broader band is designed and a test system to analyze the harvester is presented in this paper. The traditional mass is replaced by a permanent magnet in this paper, While other two permanent magnets are also placed on the upper and above of the piezoelectric cantilever. Experiments showed, under the 0.5g acceleration, compared with the traditional non-magnetic piezoelectric vibration energy harvesting, a piezoelectric cantilever (length 40mm, width 8mm, thickness 0.8mm) has a peak-peak voltage of 32.4V, effectively enlarges working frequency band from 67HZ-105HZ to 63HZ-108HZ.

Abstract: In this paper, a MEMS-based piezoelectric energy harvester is studied and the whole fabrication process is discussed. The generator structure of composite cantilever with nickel metal mass is devised. MEMS related techniques such as UV-LIGA, ion etching, XeF₂ dry etching, wet chemical etching are developed to fabricate the device. This key process includes the bonding a bulk PZT to a Si wafer, and thinning the PZT down to about 15µm in thickness after bonding by mechanical lapping and polishing method. Epoxy resin with a thickness of about 4µm is used as the intermediate adhesive layer. The formed generator is measured on vibration testing setup. The energy under the first resonant mode can be harvested, corresponding to the resonant frequency of 810 Hz . The maximum output voltage under the resonant operation is about 1.23V_p-p.