Development Of Piezoelectric Power Device And Research On The Generation Performance

Presently, the self-supplying power technology has been developing rapidly. There are many kinds of self-supplying power technology which can convert environmental energy into electric power. However, the energy supplied by self-supplying power technology is too low (almost atμW grade) due to certain confining factors, which can't meet the need of most electronic equipments, except for certain application environment. It's important to improve the electromechanical conversion efficiency for development of self-supplying power technology. There are three typical methods to convert energy into electric power: electromagnetic induction method, static (electronic capacity) conversion and piezoelectric conversion. The piezoelectric generation has been greatly valued because of its advantages of simple structure, no heating, free electromagnetic interference, easy to process, easy to achieve the aims of structural miniaturization and integration and so on. This paper develops a piezoelectric generation setting to convert mechanical vibration energy into electric power, and this setting will supply power as energy source of illumination set. The main research is listed as follows:1. Analysis of the present development of piezoelectric power Analyze the classification of micro generation set and introduce the research situation of self-supplying power sets. Expound that the piezoelectric material has great advantages in self-supplying power system. And summarize the main research direction of this paper.2. Piezoelectric ceramic material selection The performance of piezoelectric ceramic material is significant for generating ability of piezoelectric device. The electromechanical coupling coefficient K is prefer to be larger when select the piezoelectric material for power generation. Generally, the mechanical quality factor Qm of piezoelectric ceramic should be greater than 500. The relative dielectric constantεis larger. The piezoelectric constant g is smaller, and the piezoelectric constant voltage is higher. Considering the influence of piezoelectric ceramic parameters on the performance of piezoelectric generation, select the piezoelectric PZT-5H as oscillator material. Meanwhile four different piezoelectric formulas with different boundary conditions is given, which provides theoretical guidance for analysis and test of the generating capacity of piezoelectric oscillator power.3. Theoretical analysis of piezoelectric oscillatorAs an important part of the piezoelectric device, the piezoelectric oscillator plays the role in converting the mechanical energy into electric power. Analyze the influence of different supporting methods and dimension parameters on the generating capacity of the piezoelectric vibrator, which is the key part of the whole piezoelectric device design.Comparing and analyzing the cantilever pattern piezoelectric oscillator and simply supported beam pattern oscillator theoretically, we found that the generation capacity of the piezoelectric oscillator of the cantilever pattern is largely greater than the simply supported beam pattern under the same load. While the input displacement is the same, the results will be opposite. So we should consider the external excitation conditions when chose the supporting type of oscillator.4. Analysis and testing of the generating capacity of piezoelectric oscillator Build the piezoelectric vibrator models and simulate them by the finite element analysis soft combining with the professional knowledge of piezoelectricity vibration analysis and electrics. Analyze the influence of external excitation and geometry parameters on the generating capacity and the natural frequency of piezoelectric oscillator under different supporting methods. According to the theories analysis, test different piezoelectric vibrators and compared the experiment data with the FEA results, and validate the correctness of FEA method, which will provide theoretical support to choose suitable supporting types and sizes of piezoelectric oscillators in different conditions.5. Piezoelectric power device design and the development of luminous devicesIt's found that the generation capacity is quite different by different connection methods through experiment and testing. The output voltage of parallel- connection bimorphs piezoelectric oscillator which is distorted under external forces is close to the output voltage of ingle-chip oscillator, and the series-connection bimorphs oscillator which is distorted under external forces is twice to the output voltage of ingle-chip oscillator. Design three kinds of piezoelectric generation devices: inertial vibration generation device, steel-ball impacting generation device and free inertial impacting piezoelectric oscillator generation device. The generation capacity of inertial vibration generation device is weaker, but it can vibrate for quite long time, transforming and storing energy without people and supplying durative electric power. The steel-ball impacting generation device produces bending vibration when the piezoelectric vibrator is impacted instantaneously. This device can produce instantaneous great electric current, and its electric quantity can illumine a few decades of LBD with mW grade. However, the generation time is short, which will affect the luminescence durative when used for the luminescence settings. The free inertial impacting piezoelectric oscillator generation device can produce quiet heavy and increase the generating duration at the same time, and it's more suitable to supplying power for the luminescence settings than the former structures.6. Conclusion and expectationSummarizes the conclusions of this paper and look forward the next research task.