PWM interface for piezoelectric energy harvesting

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