Optimum frequency tracking of the ultrasonic motor based on a three-level constant voltage drive

Abstract

Abstract Ultrasonic motors are widely used in aerospace, smart cameras, and other applications. For ultrasonic motors to have the highest operating efficiency, the operating frequency of the motor needs to be adjusted in real time so that the motor’s operating frequency tracks the optimum frequency. Since the current research is limited to the optimum frequency tracking under constant velocity, the three-level drive parameters need to be adjusted to stabilize the velocity, which lacks precision and does not consider the frequency tracking under variable velocity. This paper explores an optimum frequency tracking scheme for ultrasonic motors under the three-level constant voltage input drive and proposes a variable step-size optimum frequency tracking scheme. The experimental results show that the optimum frequency of ultrasonic motors in variable velocity motion exists, and the proposed tracking scheme with three-level drive parameters can effectively improve the efficiency of the motor and significantly broaden the application scenario of the optimum frequency of ultrasonic motors.