A Self-Sensing Synchronous Switch Circuit for Bidirectional Piezoelectric Energy Conversion

Piezoelectric materials are versatile and widely used in many industrial applications. As a compact electromechanical transducer, a piezoelectric device not only transforms energy in either electrical-to-mechanical or mechanical-to-electrical directions but also conveys the deformation information into a measurable electrical signal. In most of the existing engineering designs, only one of the energy transformations or information-sensing functions is utilized. The interface circuit is the major obstacle against the integration of all these functions into a multifunctional application. This article explores the possibility of encapsulating all the sensing and bidirectional energy transformation functions in a single piezoelectric device by introducing a switched-mode synchronous switch interface circuit. Such a multifunctional design is realized with a multibranch modified buck-boost converter working under strong discontinuous conduction mode (DCM). The three functions operate in a time-sharing way; therefore, the information acquisition and energy transformation processes can be decoupled. In the experiment, we implement a prototyped self-sensing synchronous switch bidirectional energy conversion circuit (BECC) for energy harvesting and vibration excitation purposes. It samples the piezoelectric voltage at a rate of 500 Hz and successfully carries out the energy transformation tasks according to the software instructions. The switched-mode self-sensing BECC (SS-BECC) provides unprecedented convenience for the design of future multifunctional and miniaturized piezoelectric devices.