Equivalent circuit analysis of a single-phase rotary wedge-wave ultrasonic motor

This study presents the theoretical equivalent circuit analysis of a single-phase rotary wedge-wave ultrasonic motor (WW-USM) that was verified through simulations and experiments involving switching from the ON to the OFF transient state. The linear equivalent circuit model described herein has an initial condition and is used to derive transient wave motion responses by simple closed-form equations. The responses of the motor stator and the effects of the ON/OFF switching times of the AC source on the motor characteristics are discussed. Both the simulation and experimental results correlated closely, thus validating the numerical solution.