Development of a Simple Ultrasonic Motor Driver

This study mainly designed a simple driver for a circular cylindrical ridge-wave ultrasonic motor (RW-USM). Compared with a conventional switching resonant converter drive circuit, the drive circuit presented in this study was designed with IC-type components utilized to form a phase shifter that, in turn, was used to obtain two waveform signals with a 90-degree difference. In addition, two APEX PB50 ICs are used in the design of the amplifier circuit, which amplifies the two aforementioned signals by 11 times to drive the RW-USM. At a drive frequency of 34.868 KHz, a drive voltage of 200 Vp-p, and a preload of 1 N, an RW-USM utilizing the presented driver was found to have a maximum speed of 104.981 rpm, a maximum output torque of 3.957 mN.m, and an electromechanical transform ratio $\eta$ that was increased from 16% to 22%. The simulation and experimental results show that the presented simple IC-type driving circuit is very suitable for use in RW-USM.