Piezoelectric energy harvester with PWM electric interface

In this study, an active wideband electric interface based on pulse width modulation (PWM) for piezoelectric energy harvester is investigated. The switching interfaces are used to increase the output power of energy harvesting devices for wide frequency range. The model of a piezoelectric dynamic system is built, and the active interface is developed. It is shown that the active energy harvesting technique can effectively enable harvested power to be the maximum possible value for a dynamic electromechanical system for all frequencies. The proposed wideband interface is composed of a full bridge converter with PWM modulation. The voltage is adaptive to the vibration. A theoretical analysis is proposed and an experimental result verifies our theoretical prediction. In the final experiment, the PWM interface can harvested more energy in the case of multi-frequency vibration.