Capture Key Technology Research, Based On The Vibrational Energy Of The Piezoelectric Composites

As a new internet communication technology, wireless sensor network is developing rapidly in recent years. It has a very broad application prospect for its low energy consumption, low cost and easy implementation. However, the power supply of sensor nodes remained one of the bottlenecks in the application of wireless sensor network. New technology is badly needed to work around the self-power-supply problem of wireless sensor node. Vibration energy exists everywhere in the nature. It has been a hotspot and foreland research problem in the network research of wireless sensor to use the electric power produced by the nature vibration energy capture to replace the dry-cell as the power supply of wireless sensor nodes. The piezoelectric type utilizes the piezoelectric of the piezoelectric material to transform the vibration energy into the electrical power. It has important academic significance and practical value to the self-power-supply of sensor nodes. In this paper, together with content of National Natural Science Foundation Project, main researches have been done on the key technologies of vibration energy capture device based on piezoelectric composites. The main research content is as following.1. The power supply and energy consumption problems of wireless sensor network are analyzed and general technology problems to be solved urgently are generalized on the basis of current researches at home and abroad on the wireless sensor network and vibration energy capture technology. In this way, the research approach is determined.2. According to the reviewing correlative researches of piezoelectric composites, the composite has its distinctive features compared with original components materials for its additive property, compositionality and product. The performances of 0-3 type piezoelectric composite are analyzed. In this paper, 0-3 type piezoelectric composite is used as the piezoelectric of piezoelectric vibrator.3. Using the cantilever beam piezoelectric vibrator as the research object, it has an in-depth analysis in the cantilever piezoelectric vibrator electricity generation mechanism. The vibration theoretical model is established, the formula of each order natural frequency is deduced; and the relevance between the modal parameters and natural frequency is analysis. Moreover, the electromechanical conversion mechanism of piezoelectric vibrator is analyzed, the electricity generating theoretical model is established and the relevance between the parameters of the cantilever and the voltage produced by the cantilever is analysised. These consequences established a theoretical foundation for the computer simulation and the experiment research. 4. Finite element model of piezoelectric vibrator is built by ANSYS10.0, The static and modal analysis has been done in this paper. Relevance between parameters of the cantilever and its natural frequency is simulated and the electric power generation capacity of different sizes piezoelectric vibrators is finite analyzed. These consequences can be the foundation for designing the best structure size cantilever piezoelectric vibrator.5. Vibration electric generation experiment platform is built to test the capacity of the piezoelectric vibrator. The experiment results verify the accuracy and effectiveness of the theoretical and finite compute simulation analysis.6. On this basis, electric power harvest and storage circuit is designed in this paper. The circuit can keep the voltage-output at +5V produced by the piezoelectric vibrator which can meet the energy consumption needs of wireless sensor network nodes when the frequency of vibration exciter is 100Hz and the active voltage of swept signal generator is 1Vrms.In conclusion, the in-depth researches of the vibration electric generate of cantilever piezoelectric vibrator have been done by theoretical research, computer simulation and experiment research. The vibration energy capture system designed in this paper can meet the self-power-supply needs of wireless sensor nodes which have the advantages of maintained power supply, environmental protection, energy saving, simpleness and practical applicability. This system can supply the foundation for the design of vibration energy capture device. In this paper, beneficial exploration has been done for the theoretical research and the application of utilizing the nature energy as the power supply of wireless sensor nodes.