Power and frequency bandwidth improvement of piezoelectric energy harvesting devices using phase-shifted synchronous electric charge extraction interface circuit

This article presents a new way to control the synchronous electric charge extraction interface circuit, which was formerly developed to improve the performances of piezoelectric vibration energy harvesting devices. An analytical model for energy harvesting systems including this new technique, called phase-shift synchronous electric charge extraction, is proposed. This model is then used to study the properties of this new control scheme in the cases of low and high electromechanical coupling. Contrary to the synchronous electric charge extraction technique which exhibited significant improvements in terms of harvested power for piezoelectric devices with low electromechanical coupling, the phase-shift synchronous electric charge extraction technique shows capability to increase the harvested power up to the theoretical limit for piezoelectric devices with high electromechanical coupling. In addition, the presented theoretical results show that the frequency bandwidth of piezoelectric energy harvesting devices may be substantially increased.