Direct Adaptive SSDV Circuit for Piezoelectric Shunt Damping

Piezoelectric shunt damping is widely studied to suppress vibration of thin structures via shunting an attached piezoelectric transducer with an electrical impedance. The synchronized switch damping on voltage (SSDV) technique can be used to enhance the damping effect. However, SSDV is not stable in the weak excitation. Although some adaptive SSDV circuits have been developed to tackle the stability problems, additional monitoring devices are required to provide feedback for the vibration strength signal for adjusting the series voltage sources. We here present a new direct adaptive SSDV (DA-SSDV) method without an additional excitation level monitoring module, based on the ratio of the maximum piezo voltage and the value of the series voltage sources. A compact DA-SSDV circuit is designed with low-cost off-the-shelf discrete components. The closed-loop control of the series voltage sources is realized simply through a passive envelope detector and a resistive voltage divider. Experimental results show that the DA-SSDV circuit avoids the stability problems and possesses good displacement transmissibility around 6.2, a fast voltage adjustment response speed above 5 V/s, and high operation sensitivity with the open-circuit piezo voltage of 540 mV. The DA-SSDV shows great application value in compact and low-power vibration control systems.