Electromagnetic vibration harvester with piezoelectrically tunable resonance frequency

This paper presents an electromagnetic vibration scavenger that exhibits a tunable eigenfrequency. By applying a static electrical field the eigenfrequency can be shifted. This feature is originated from exploiting the elastostriction of the utilized piezoelectric bimorph suspension. It is demonstrated that in the tuning operation mode more than 50 µW are scavenged continuously across the feasible frequency range of 20 Hz.