Micro-power converters for energy harvesting devices

This paper demonstrate the feasibility of micro-power converters based on active control for harvesting power from multiple tiny piezoelectric transducers with higher efficiency than conventional passive approaches, especially in case of irregular vibrations and heterogeneous transducers. A prototype system was developed and validated in realistic conditions: three 0.5×12.7×31.8 mm³ piezoelectric cantilevers with 18g tip masses were excited with the vibrations of a train passenger car. The converter harvested up to 142μW@0.22g-RMS and up to 90μW@0.11g-RMS. An implementation based on discrete components including passive start-up and implementing basic power management techniques consumes a fraction of the extra harvested power during operation.