Analysis of the push-pull convertor used in ultrasonic motor drive

The push-pull convertor is widely used in ultrasonic motor drive as a DC/AC step-up convertor. In this application, the load of the convertor is the LC series compensation circuit in general. Because the operation mode is different from the traditional DC/DC applications, and also because of the non-linearity of the load, the push-pull convertor used in ultrasonic motor drive has more complex operation. This paper analyzes its operation in detail. The analysis will help to make right design of the convertor, and also will help to understand the non-linearity of ultrasonic motor driving unit.