Design Manufacture Of Piezoelectric And Electromagnetic Hybrid Micro Power Generator With Low Frequency Response

Energy supply has become increasingly prominent in the field of wireless sensor network,implanted monitoring system, portable electronic appliance and micro-device in harsh scenario. With the disadvantages of large volume, short service life, poor environmental adaptability, limited energy storage, replaced often even complex and power cable, the traditional battery has been unable to meet the self-powered need of the systems. The piezoelectric and electromagnetic hybrid micro power generator is proposed to efficiently convert environmental vibration energy into electrical energy, which has important scientific significance for the self-powered technology development.The foundation structure is PZT-based four helical cantilever beams, mass block with Au coil and Nd2Fe14 B permanent magnets. When the device is driven by ambient vibration,helical cantilever beams and magnetic induction coil follow mass block motion. According to the piezoelectric effect of PZT piezoelectric material grown on the cantilevers, the upper and lower surfaces of PZT films occur potential differences. Piezoelectric energy is collected by extraction electrodes. As Faraday law of electromagnetic induction mentioned, coil incises the magnetic line and produces electromotive force in the meantime. Electromagnetic energy is gathered with the electrodes. The piezoelectric module design can effectively reduce the devices resonant frequency, suitable for ambient vibration environment with the frequency of163.6Hz in the modal analysis. Combined with induction coils and Nd2Fe14 B magnets integrated design, a novel idea of the future research of MEMS hybrid power generator provided with low frequency response and high power output is provided.Through theoretical analysis of piezoelectric and electromagnetic generating mechanism,PZT films, with high electromechanical coupling coefficient, piezoelectric constant and approach to manufacture mature, Nd2Fe14 B, with high remanence, coercivity and maximum magnetic energy product, Au, with low resistivity and good stability, are selected as the critical materials. The overall design dimension parameters are optimized by simulation and theoretical calculation. Manufacturing technology process and corresponding photoetchingmasks are designed in detail. Through researching the influence of different PZT hydrocolloid and cooling process after annealing on the PZT films quality, PZT piezoelectric films(about3 μm) are achieved by sol-gel tech, showing uniform and compact surface topography and high dielectric property. The integrated manufacturing of vibrational piezoelectric and electromagnetic hybrid micro power generator is realized by using MEMS micromachining process, metalloscope obvservation and micro assembly with magnet. MEMS micromachining process includes lithography, wet etching, IBE, magnetron sputtering, lift-off,CVD, RIE, ICP etching, dicing technology, bonding process and so on. Finally, establish the test system and carry on the preliminary test and analysis.