Evaluation of energy harvesting by using piezoelectric unimorph ceramics

By using the piezoelectric direct effect, piezoelectric energy harvesters hold the promise of providing an alternative power generating device. Also, ambient vibration is the focus to provide the amount of available mechanical energy resource that can be converted into electricity by piezoelectric ceramics. Design and analysis of the piezoelectric unimorph ceramic and electric converter as well as efficiency of electromechanical conversion and energy storage is studied in this article. In experiment, electric power 33.84mW is gained by a capacitor 470µF and a load resistor 10.4M-ohm at low operating frequency of 2.5Hz for 25 seconds, for example. The effectiveness of this electric power to fully charge a NiMH battery only needs 30 minutes.