A Study of Resonance Tracking Control for Langevin Typed Piezoelectric Vibrator

Abstract

Accurate control method for Langevin typed ultrasonic vibrator has been just achieved. In this development, the behavior of phase difference between voltage and current of piezoelectric device is applied to keep the state of resonance, which was formally proposed by the author in the field of ultrasonic motors. High power piezoelectric devices usually require pulse driven MOSFET in order to obtain high efficiency. However, its process tends to generate a lot of noise compared with sinusoidal wave driving. The experimental result shows the availability of the method in case of pulse driving.