Design of Wall-plug Efficiency Optimized Semi-active Piezoelectric Shunt Damping Systems

Analysis of the wall-plug efficiency, i.e. the ratio of reflected and absorbed acoustic power over the total electric input power, of semi-active vibration control devices based on the principle of Piezoelectric Shunt Damping is presented. The vibration suppression element in the considered vibration control device consists of a piezoelectric actuator, which is connected to the active synthetic impedance shunt circuit that emulates a negative capacitance. Two types of power amplifiers can be used in the implementation of the synthetic impedance: linear (class B, AB) and switching (class D). Strengths and weaknesses of the two aforementioned implementations of the synthetic impedance shunt circuit in the semi-active vibration control device are analyzed. The key factor in the analysis is the wall-plug efficiency. Principles that can enhance the wall-plug efficiency of the device are discussed.