Study On The Nonlinear Dynamic Behaviors Inside A Piezoelectric Energy-harvesting/storage System And The Relative Integrated Optimization

The wireless power supply technology for the development of micromation and integration of new generation sensor technology is bottleneck that needs to break though. Among all kinds of energy harvesters, the piezoelectric energy is the most promised one because the piezoelectric materials are natural candidates for converting mechanical energy into electric energy with low loss in the energy converting process. This paper puts up a mount of study on the nonlinear dynamic behaviors and relative integrated optimization on the piezoelectric energy harvesting/storing system, obtains a lot of innovative results. Specific contents are as follows:(1) This paper establishes a novel intermittent nonlinear coupling model of piezoelectric energy harvesting/storage system spaning structure analysis and electrics circuit design fields. The dynamics performance of the harvesting structure under the turning of the open and close circuit conditions is calfully analysed. The multi-time scale interaction mechanisms and the mechanism of how the circuit influence the dynamic characteristic of harvesting structure is analysed, the integral analysis and optimization of piezoelectric energy harvester is then realized.(2) The machanism of how the load mode and temperature influence the performances of piezoelectric harvester is studied, and an appropriate frequency adjusting and temperature compensating strategy to enhance the environmental adaptability of piezoelectric energy harvester is developed, which gives the energy harvester better adapbility on enenvironment influence. In order to strength the interaction between the energy hatvester and the environment with varying frequency, two novel approaches for designing piezoelectric harvesters with adjustable and broad operating frequency-band are presented. Numerical results show that the harvesting efficiency of these devices is several times higher than the harvesters without frequency adjusting function. On the other side, temperature-induce d frequency shift in a thickness mode bulk piezoelectric device with a layer of another material for temperature compensation is analysed. It is shown that with a proper design of the compensation layer the temperature sensitivity can be reduced or made zero.(3) The nonlinear behavior distinction of piezoelectric energy harvester near resonance is studied, multi-valuedness and jump phenomena at resonance region of the output power are found, the influence of the driving force and circuit load to the nonlinear region which gives an important guidance of device design are analyzed.(4) The machanism of how the electrode on the surface of piezoelectric structure influce its integral performance is studied. Two noval methods for the electrode optimization are developed, the stress concentration effect near the edge of an electrode has been reduced, and the reliability of the piezoelectric harvester is enhanced a lot.This paper breakthroughs several key and/or difficult problems in the analysis and design of piezoelectric energy harvesting device, develops a variety of new type of piezoelectric energy harvesters with much better performance than the traditional one. Several research blanks of the international community in this field are filled, a series of valuable methods and conclusions suit to different harvesting model are obtained. These achievements have instructional significance to enhance the integral performance of the piezoelectric energy harvester. By conducting this kind of study, the cross and penetration of sentific subjects can be further promoted.