Analysis of Piezoelectric Buzzers as Vibration Energy Harvesters

Abstract

This paper studies the energy harvesting capability of piezoelectric buzzer elements which are primarily used in electro-acoustic applications. Two commercially available piezo buzzer elements were analysed for their vibration energy harvesting capabilities under mechanical preload condition. A maximum power of 220 uW across a (resistive) load of 126 kΩ was obtained for a 35mm piezo buzzer with a preload of 57gms whereas for a 27mm buzzer the maximum power delivered to a load of 133 kΩ was 86 uW with a preload of 25gms. Resonance frequencies for the two buzzers were found to be 22Hz and 24Hz respectively at an acceleration of 2 m/s2. The buzzer elements were used to successfully charge a supercapacitor up to 5 volts which was used to power a microcontroller. Results show that piezo buzzers are viable as vibration energy harvesters, capable of powering low-power microelectronic devices.