Key Techniques On Vibration-Powered Energy Harvesting Based On Piezoelectric Ceramic

How to obtain armaments'conditions and then transmit them without wires is one of important research directions in condition monitoring areas. The development of wireless sensor networks provides a good solution for it. As to wireless sensors, power supply is a major bottleneck problem affecting their applications. The traditional way of using electrochemical batteries have such disadvantages as inconvenient install and uninstall, periodical replacement and expensive maintenance costs, so it is necessary to find another way to power wireless sensors permanently. Nowadays emerging harvesting energy technologies become a research hotspot in condition monitoring areas, which transform other energy sources to electrical energy. It is of great important significance to self-power wireless sensors.As to armaments, vibration is just an ideal energy source. Funded by National Defense Basis Research Project, Armament Advanced Research Project and National Science Foundation Project of China, in this paper some key techniques of vibration energy harvesting based on piezoelectric ceramic are deeply studied. The electricity generation principles based on piezoelectric cantilever beams is analyzed. Then theoretical and finite element models are built. In the end, finite element analysis and experiments are done.The detailed contents and innovative work of this paper are as follows.1. The development of vibration energy harvesting based on piezoelectric ceramic at home and abroad is reviewed and then key technologies needed to be are analyzed and summarized, which is the basis of this paper.2. Considering piezoelectric cantilever vibrators as a research object, the electricity generation principles of piezoelectric cantilever beams is analyzed and corresponding mathematic models are built, which will be the basis of finite element simulation and experiments. As to the problem of uneven strain distribution in rectangular piezoelectric cantilever vibrators, piezoelectric cantilever vibrators with different geometry are studied. The results show that under the same conditions triangular cantilever beams can improve the strain distribution and generate more voltage than trapezoidal ones; rectangular ones are the worst.3. Finite element models piezoelectric cantilever beams are built and then static and mode analysis are presented by finite element analysis methods. Effecting relationships between geometry parameters of a piezoelectric cantilever beams and its electricity output as well as resonant frequencies are studied. The analysis results are consistent with those of theoretical analysis, which will be helpful to optimal designing of piezoelectric cantilever beams.4. An experiment set-up is designed and built and a conversion and store circuit is studied. Different experiments on vibration-powered behaviors of piezoelectric cantilever beams are studied in detail. Experimental results validate the validity of theoretical and finite element analysis.In conclusions, combined with theoretical, finite element and experimental analysis, vibration-powered behaviors of piezoelectric cantilever beams are deeply studied in this paper. The result shows that tens of millwatt power can be obtained by optimally designed piezoelectric cantilever vibrators, so it is feasible to power wireless sensors in the future.