Effects of a Series Capacitor on the Energy Consumption in Piezoelectric Transducers at High Vibration Amplitude Level

Abstract

In this paper, a driving method for low-loss generation in piezoelectric transducers at a high vibration amplitude level is presented. First, we analyze the power consumption of several loss mechanisms of piezoelectric transducers using an electrical equivalent circuit model. In this model, loss due to piezoelectric effect is explicitly represented by a series resistor, and pure dielectric loss is separately denoted by a parallel resistor. Mechanical loss is represented by a series resistor in the mechanical arm. The reason for the high efficiency at the anti resonance frequency is explained by this analysis. Next, the effect of an external series capacitor is discussed by comparing the experiment with the calculation, based on the equivalent circuit model for the high vibration amplitude level. By using the external series capacitor, the loss generated at the high vibration amplitude was significantly reduced without a large increase in electrical impedance.