Simulation model for ultrasonic motors powered by resonant converters

A rotary traveling wave type ultrasonic motor powered by a resonant converter is modeled to optimize the overall drive performance by simulation and to develop suitable control strategies for the drive. Based on mechanical approaches in modeling the stator under consideration of unsymmetries and reflecting the nonlinear stator/rotor-contact by an elastic contact model, an extended contact model of the stator/rotor interaction with closed form solutions for nonideal traveling waves is derived referring to a two-mode approximation of the stator and piezoceramic. By incorporation of a converter model into the mechanical subsystem, a proper simulation model for ultrasonic drives is presented, whereby some interesting phenomena are verified by simulations and explained by strong graphical means.