Design and Analysis of a Wireless Ultrasonic Motor Drive System

In this letter, a novel wireless motor system, namely, the wireless ultrasonic motor (WUM) system, is proposed and analyzed. A unique wireless drive topology is designed to solve the problems of the existing wireless drives, such as complex controller and converter at both the transmitting and receiving sides, regular maintenance, and output ripple resulted from motor type and control scheme. The key is to combine the merits of the wireless power transfer and ultrasonic motor to wirelessly energize the ultrasonic motor with high-frequency voltage directly. Meanwhile, a matching inductor is designed for the proposed wireless drive to improve power quality and to filter harmonic voltages at the motor side. Furthermore, laminated coil structure is optimized with electromagnetic decoupled ability and less ferrite core. Two-mode motor control method is designed to extend the speed range of the proposed WUM drive. Finally, operating principles and experimental results are provided to verify the feasibility and correctness of the proposed WUM drive system.