Research on Inherent Frequency and Vibration Characteristics of Sandwich Piezoelectric Ceramic Transducer

Abstract

Great progress has been made in the field of ultrasonic processing in recent years, and piezoelectric ceramic transducers have been widely used as drive sources. In this paper, a sandwich piezoelectric ceramic transducer is designed, and the vibration of each part of the transducer is analyzed by elastic mechanics and piezoelectric theory. According to its mechanical and electrical boundary conditions, the vibration model of the piezoelectric transducer was established. Based on the equivalent elastic modulus method for simplifying the pre-stressed bolts into a one-dimensional transducer vibration model, the relationship between the one-dimensional axial response frequency of the transducer and the length of each component was obtained. Based on the half wavelength theory, a transducer with the vibration node in the crystal stack and an inherent frequency of 15 kHz was designed and fabricated. In order to verify the natural frequency and vibration characteristics of the piezoelectric transducer, a laser vibration measurement system was built in this study. The vibration characteristics of the transducer under different parameters such as voltage and frequency were analyzed, and the accuracy of the vibration model was verified. The vibration states of the end surface of the transducer and the radial surface were evaluated at the first-order inherent frequency and second-order inherent frequency. The results show that the equivalent simplified model established in this study can effectively design the inherent frequency of the transducer, and the operation at the first-order inherent frequency meets the one-dimensional assumptions of this study. The transducer operating conditions measured in this study also provide a more detailed reference for ultrasonic processing applications.

A Driving Power Supply for Piezoelectric Transducers Based on an Improved LC Matching Network

“…A piezoelectric transducer is an oscillating unit that can achieve maximum power transfer only if it is made to work in a resonance state [ 11 , 12 ]. When the system environment and working conditions change, the piezoelectric transducer impedance and series resonance frequency also change [ 13 , 14 ], the frequency tracking function makes the ultrasonic power supply operating frequency follow the transducer series resonance frequency change accurately and timely to ensure that the transducer always works in the resonance state [ 15 ]. The power adjustment function regulates the electrical energy delivered to the piezoelectric transducer by the ultrasonic power supply and controls the vibration amplitude of the piezoelectric transducer output in order to adapt to a variety of welding conditions [ 16 ].…”