A piezoelectric motor driven by a single-phase signal

Abstract

This paper aims to present a proof-of-concept for a novel piezoelectric motor using a single-phase driving signal. The stator is constructed by bonding a Terfenol-D plate and a piezoelectric ceramic (PZT) plate onto the outer surface of a metal base. The PZT plate based on d<inf>31</inf> effect is used to simultaneously excite two in-plane bending modes of the stator. Similarly, the Terfenol-D plate can also be used to excite the two bending modes. By superposition of the two bending modes, elliptical motions of the stator surface points are generated. The working modes and vibration characteristics of the motor are analyzed by finite element analysis software. The resonance frequencies of the two bending modes are tuned to be close by additional mass. The dimensions of the stator are optimized to maximize the output displacement. To confirm the feasibility of the proposed design, a prototype motor is fabricated and tested. The size of the prototype motor is about 11.2×10.7×28.0 mm³. The tested resonance frequencies of the two bending modes are 16.0820 kHz and 16.3476 kHz respectively. The maximum no-load speed is 85 rpm. The applied driving voltage is 100 V<inf>o-p</inf> (peak voltage) at a frequency of 16.34 kHz.