Design and Fabrication of a High Efficiency Piezoelectric Vibration-Induced Micro Power Generator

To fulfill the increasing self-power demanding of the embedded and remote microsystems, theoretical and experimental study of a piezoelectric vibration-induced micro power generator that can convert mechanical vibration energy into electrical energy is presented. A complete energy conversion model regarding the piezoelectric transducer is discussed first. To verify the theoretical analysis, two clusters of transducer structures are fabricated. The piezoelectric lead zirconate titanate (PZT) material that has better energy conversion efficiency among the piezoelectric materials is chosen to make of the energy conversion transducer. The desired shape of the piezoelectric generator with its resonance frequency in accordance with the ambient vibration source is designed by finite element analysis (FEA) approach. Conducting wires and load resistor are soldered on the electrodes to output and measure the vibration induced electrical power. Experimental results shows that the maximum output voltages are generated at the first mode resonance frequencies of the structure. It is also found from the experimental results that the induced voltage is irrelevant to the width of the structure but is inverse proportion to the length of the structure. It takes 7 minutes to charge a 10,000 μF capacitors array to a 7 V level. The total amount of electricity and energy stored in the capacitors are 0.7 Coulomb and 0.245 J, respectively. The experimental results are coincidence with the theoretical analysis.