Self-powered piezoelectric energy harvesting device using velocity control synchronized switching technique

With the rapid development of low power consumption electronics, wireless sensor networks (WSN) are highly investigated and used to improve our life quality. Using piezoelectric materials to transfer the mechanical energy into electrical energy for batteries of WSN in order to extend the life time is the focus in many researches in the recent years. It is important and efficient to improve the energy harvesting by designing an optimal interface between piezoelectric device and the load. In this paper, a self-powered piezoelectric energy harvesting device is proposed based on the velocity control synchronized switching technique (V-SSHI). Comparing to diode full bridge rectifier standard technique, the synchronized switching harvesting on inductor (SSHI) technique can highly improve harvesting efficiency. However, in real applications when the energy harvesting device is associated with WSN, the SSHI technique needs to be implemented and requires being self-powered. The conventional technique to implement the self-powered SSHI is to use bipolar transistor as voltage peak detector. In this paper, a new self-powered device is proposed, using velocity control to switch the MOSFET more accurately than in the conventional technique. The concept of design and theoretical analysis is presented in detail. Experimental results are examined and show better performance.