Piezoelectric Energy Harvesting

Project Description

This project investigates the use of piezoelectric elements to harvest electrical energy from small mechanical vibrations. One possible application is a wireless electrical power supply for tiny sensors embedded in structures such as buildings or bridges. Instead of a battery or wired power supply, the sensor would harvest its power from the tiny mechanical vibrations in the structure.

In the experimental setup, we will attach a PZT plate (piezoelectric ceramic device) to the side of a tuning fork with a resonant frequency of about 4 kHz. When excited by irregular mechanical perturbations, the tuning fork will vibrate at its resonant frequency. The piezoelectric element will be connected to a shunt L-C circuit with a resonant frequency close to that of the tuning fork. According to coupled mode theory, the energy in the system should oscillate between the mechanical and electrical modes at a beat frequency approximately equal to the difference between the resonant frequencies of the two modes. Our goal is to successfully observe this phenomenon and find how to achieve the highest electromechanical coupling and lowest loss possible. By choosing the proper beat frequency, it should be possible to transfer the system’s energy into a battery while it is in the electrical mode.