Reseach On Piezoelectric Generator For Mobile Terminal With Composite Beam Structure

At present mobile phones has become the indispensable products in daily life, but the poor battery life of smart phones or big screen phones is always a big problem to consumers and mobile phone manufacturers. Based on theoretical and experimental comparison of different piezoelectric generator structure performance, a kind of piezoelectric generator consisted of multi-vibrators with composite beam structure was innovatively presented, which could not only meet the wide frequency response spectrum of mobile phones, but also absorb more vibration energy by the whole beams bending and pass it to the piezoelectric vibrator. The FEM simulation analysis was introduced to find out the most adapted model parameters to the spectral response of mobile phones. The portable package design(mobile phone casing) and associated circuitry design which has been tested were both accomplished. Specific researches as follows:1. The comparison in the repeatedly test between the cantilever structure and the simply supported structure which both may be used in the piezoelectric generator structure in the phones showed that the piezoelectric vibrator with cantilever structure was more suitable for mobile phones application environment.2. To be able to design a piezoelectric generator which has a similar frequency response spectrum with the phones to achieve the best effect of energy collection, vibration frequency spectrum of the mobile phone when it knocked on the palm was repeatedly tested and the first peak frequency was at 1600 Hz.3. Through the comparison between the experimental testing result of the piezoelectric cantilever vibrator and the FEM simulation result of the same size Ansys finite element model, the vibrational frequency, the peak voltage and the peak displacement results were all very close, verifying the Ansys FEM analysis feasibility of the piezoelectric generator structure.4. Depending on the actual application situation and the characteristic of piezoelectric cantilever generator, a kind of piezoelectric generator consisted of multi-vibrators with composite beam structure was innovatively presented. The output performance of the presented piezoelectric generator in different material parameters and acoustic parameters was studied in Ansys simulation method. According to the research analysis a final parameter of the piezoelectric generator consisted of multi-vibrators with composite beam structure was determined. Its simulation frequency response spectrum matched the test result very well.5. A Beautiful, practical and feasible portable mobile phone casing was designed to package the piezoelectric generator. All the design drawing of the component and assembly method and the final overall preview include the mobile phone was presented.6.Depending on the experiment result of one piezoelectric vibrator a charging circuit meeting the mobile phone charging requirements was designed. The test result showed that the designed circuit achieved the expected function.