Design and analysis of unsymmetrical SSD based negative capacitance technique for vibration suppression

Abstract

Synchronized switch damping on negative capacitance (SSDNC), as one of the nonlinear synchronized switch damping (SSD) techniques, has been received much attention in recent years. The damping effect depends on the effective voltage on the piezoelectric actuator in SSDNC control. The applicable bipolar voltage of a piezoelectric element is unsymmetrical. However, the voltage on the piezoelectric actuator is applied symmetrically in SSDNC, which greatly wastes the driving capability. An unsymmetrical SSDNC (un-SSDNC) is proposed in this paper to further boost the voltage on the PZT actuator and make full use of the driving ability to improve the control performance. A bypass capacitor, two diodes and switches are attached to the SSDNC circuit to realize unsymmetrical bipolar voltage. The control logic of the switches is introduced and the switched voltage is derived as well as the control performance. Experiments and simulations were carried out to verify the designed circuit and the theoretical results of the switched voltage. The influence of the bypass capacitor on the switched voltage and the stability of the un-SSDNC system were investigated. The voltage ratio and control performance increase with increasing bypass capacitor, but too large of bypass capacitor will cause the problem of system stability.