Design and manufacture of LLC resonant ultrasonic motor drive circuit1

A practical drive circuit for traveling wave ultrasonic motor is designed in this paper. The drive circuit is mainly composed by square-wave inverter and LLC resonant transformer. Harmonics of square-wave generated by DC-AC inverter is reduced by the transformer's leakage inductance. The input current of the drive circuit is reduced by transform's secondary inductance. The manufacture of the transformer is also illustrated. Experiment results show that the drive circuit can drive the motor effectively and efficiently.