Comparative analysis of piezoelectric power harvesting circuits for rechargeable batteries

Using piezoelectric materials to harvest energy from ambient vibrations to power wireless sensors has been of great interest over the past few years. Due to the power output of the piezoelectric materials is relatively low, rechargeable battery is considered as one kind of energy storage to accumulate the harvested energy for intermittent use. Piezoelectric harvesting circuits for rechargeable batteries have two schemes: non-adaptive and adaptive ones. A non-adaptive harvesting scheme includes a conventional diode bridge rectifier and a passive circuit. In recent years, several researchers have developed adaptive schemes for the harvesting circuit. Among them, the adaptive harvesting scheme by Ottman et al. is the most promising. This paper is aimed to quantify the performances of adaptive and non-adaptive schemes and to discuss their performance characteristics.