Elucidating negative capacitance design in piezoelectric circuitry to facilitate vibration suppression enhancement assisted by energy harvesting

Owing to their two-way electro-mechanical coupling, piezoelectric transducers have been widely used in vibration control and energy harvesting systems, the performance of which can be boosted by circuitry integrations. Inductive shunt generally benefits the system performance around the resonant frequencies, and op-amp based negative capacitance (NC) element can increase the apparent electro-mechanical coupling by offsetting the piezoelectric inherent capacitance. This research aims at elucidating the NC design in an integrated piezoelectric inductive shunt for simultaneous vibration suppression enhancement and energy harvesting. In particular, the new concept is to leverage the energy harvesting capacity of the piezoelectric circuitry to supply power to a rechargeable battery to drive the NC element, thereby leading to a new design that enhances passive vibration suppression without requesting external power supply. An analytical model that links the NC internal parameters with the system-level responses including vibration suppression enhancement and energy harvesting is presented. The influence of NC internal parameters is analyzed, aiming at improving vibration suppression while maintaining the positive net power which is the difference between the power generated through energy harvesting and the power consumed by the NC element. The design boundaries and uncertainty effects are examined. The analytical results are demonstrated and validated through experiment. This research reveals the potential of a self-sustainable, integrated piezoelectric circuitry for vibration suppression enhancement. The systematic analysis of NC element can be extended to a variety of designs of vibration/wave control utilizing piezoelectric circuitry.