Study on driving circuit of the ultrasonic motor

The ultrasonic motor driving fluid directly is a new type non-contact ultrasonic motor, it resolves the problems of the traditional ultrasonic motor caused by friction, such as shorter life expectancy and continuous running time. It has the distinct characteristic that applies the fluid between the stator and the rotor. According to the character of the ultrasonic motor, this paper designed a set of variable-frequency driving circuit. The signal with adjustable frequency is generated by the voltage controlled oscillator, then the signal is shifted in phase, so four sets square-wave signals that have the same effective value and the same frequency and differ 90 degrees in the phase are generated, which can be applied to drive two sets of push-pull circuit. The output signals of the push-pull circuit are transmitted to transforms for the aim of step up so as to drive the motor. The frequency can be regulated through regulating the supply voltage and the resistance of VCO. The driving figure and the basis character of the motor are obtained by this proposed circuit. The structure of the circuit is simple, and the driving frequency and voltage is easy to regulate. The circuit meets the requirement of the motor.