Micro-Piezoelectric Generator Experimental Design And Application Research

In recent years, research on the energy harvesting using piezoelectric material has caught people's more attention, the merits of energy conservation and environmental protection attract people to pay more attention to it, and the generator made by piezoelectric material has merits as followed: simple structure, low cost, easy operation, and miniaturization.First of all, there is an introduction about the piezoelectric energy harvesting and the applications of piezoelectric energy haversting.And then it is based on the basic theory of piezoelectric energy harvesting to introduce ceramics material, piezoelectric effect, piezoelectric vibrator and their vibration pattern and equivalent circuit. More over it is introduced that the effect of the support and power for power output of the piezoelectric vibrator.The measures to solve the problem are as followed:The curved Theory of Vibration and piezoelectric relevance knowledge is used to analyze the rectangle piezoelectric vibrator and the circle shape piezoelectric vibrator respectively, it provides theory basis to optimize piezoelectric vibrator design. Analytical results are indicated: When there is identical displacement to rectangle piezoelectric vibrator at free boundary, voltage from bending vibration increase with natural frequency , the piezoelectric constant , the beam mass density , piezoelectric ceramics thickness , exciting the amplitude , reducing with dielectric constant , the beam length , unit length amplitude; The electric charge increase with width of beam; it is analyzed that the best of piezoelectric wafer affixing is the root segment in the cantilever beam. The main analysis of circle shape piezoelectric vibrator is vibration, the results indicates that synonym frequency of circle shape piezoelectric vibrator reduces with the radius square, recreating with thickness, at the same time it is effected by other parameters (including the ratio of ceramics wafer thickness and base board thickness, the ratio of the ceramics wafer diameter and base board diameter).There is some experiment analysis about the factor affecting the electric power generation ability of the rectangle piezoelectric vibrator and the circle shape piezoelectric vibrator, it is summed up that the power output rules of the structure parameters of the piezoelectric vibrator (including length, broad, thickness, the diameter, the ratio of ceramics wafer thickness and base board thickness, the ratio of the ceramics wafer diameter and base board diameter) impedance matching, stimulating force and the amplitude at free boundary, and the reason of the law is analysed.The correctness having been verified, at the same time it provide experiment basis for the piezoelectric generator design.Two kinds of generators are designed based on theoretical analysis and experiment: the cantilever support piezoelectric generator and simply supported boundary pressing piezoelectric generator, at the same time, the vibrator is designed and chosen. The experiment has tested the ability of the two kinds of electric power generator, there is a comparison for them about the ability of power output, and experiment analysis indicates that the cantilever piezoelectric generator can output more power.There is an attempt to apply piezoelectric generator to RF wireless system. First of all, it is introduced that the functional requirement and technical requirement of the RF wireless system, Then the wireless transmission circuit, the wireless accepting circuit as well as the receiving and dispatching system software are designed, and the electric appliance parameters are determined, simultaneously it is carried on the system low power loss to design. Finally the power source control circuit are designed, which solves the problem that the voltage of piezoelectric power generator is unable to last, the control circuit can make the piezoelectric power generator to provide continues about 1s the voltage signal.There is a test on the piezoelectric power generator and the control circuit as well as the RF wireless system, the experimental result has indicated that the power output capacity of cantilever support piezoelectric power generator is higher than the simple support piezoelectric power generator, it is up to 13.28%, it is also higher to 36.4%than the efficiency(25%) that point out by Miki UMEDA etc.the electrical energy which the piezoelectric power generator produces satisfies the power supply request of RF wireless system. Through optimized design, the performance of micro-piezoelectric generator is better and it is worth application.