Least Lossy Piezoelectric Energy-Harvesting Charger

Abstract

Wireless microsensors can operate indefinitely when they use ambient kinetic energy in motion to replenish the battery. Of available technologies, a switched inductor can draw the most power from a piezoelectric transducer. Power consumption, however, limits how much of that power the battery receives. This paper theorizes and shows that drawing and delivering power with an inductor from the transducer into the battery directly reduces the energy the inductor carries. With less energy, inductor current and related ohmic losses are lower. This way, ohmic losses can be up to 74% lower. This is why the switched-inductor bridge is the least lossy piezoelectric charger in the state of the art.