An energy autonomous switching converter for harvesting power from multiple piezoelectric transducers

This paper introduces a power conversion technique
based on active control for harvesting power from multiple
piezoelectric transducers with higher efficiency than
conventional passive approaches. The proposed scheme allows
each source to operate efficiently, 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 142?W@0.22g-RMS and up to
90?W@0.11g-RMS. An implementation based on discrete
components including passive startup and basic power
management consumes a fraction of the extra harvested power
as little as 5.5?W per source during operation. The structure is
modular and the number of sources can be easily increased
without affecting power consumption.