Dynamic analysis of inverter-fed ultrasonic motors

A rotary traveling wave type ultrasonic motor powered by a resonant power converter is analyzed by simulation to optimize the overall drive performance and to develop suitable control strategies for the drive. Based on a detailed simulation model for the total electromechanical system of the drive, various phenomena such as the well known pull-out phenomenon are verified by individual modeling aspects and explained by simulation. As the total characteristics are reflected by the simulation model and verified by measurements, a general control scheme for speed variable ultrasonic drives is suggested ensuring optimal torque utilization and minimized losses.