Actively controlled power conversion techniques for piezoelectric energy harvesting applications

Abstract

The current advances in ultra-low power design let foresee great opportunities in energy harvesting platforms for self-powered systems. This paper presents two conversion schemes based on active control for harvesting energy with a higher efficiency than traditional passive approaches. A prototype has been developed and the approaches have been validated for piezoelectric energy harvesters with both measurements in realistic conditions (i.e. irregular vibrations) and mixed-signal circuital simulations. The proposed converters may increase harvested power of at least 25% and up to three times with respect to a passive rectifier. The harvested power is about 40 μW in presence of weak vibrations (aRMS = 1.18 m/s2) obtained in a train passenger car in motion with a 28 × 6 × 0.5 mm3 cantilever made of PZT-A4E with a 20 g mass attached at the free end. © 2010 Springer Science+Business Media B.V.