Design and performance analysis of ultrasonic generator for giant magnetostrictive transducer

The ultrasonic generator for giant magnetostrictive transducer (GMT) is different from the traditional ones for piezoelectric transducers. However, there are few relevant reports of generators for GMT. In this investigation, the equivalent circuit model of GMT with contactless energy transfer was established, and an ultrasonic generator for GMT was designed. The frequency source circuit was based on direct digital synthesis (DDS), and a full-bridge switching circuit was used for power amplification. The frequency tracking strategy was implemented based on the phase sampling and RMS calculation modules, so that the ultrasonic generator could output signals with fixed frequencies and realize frequency tracking. Finally, the performance of the generator was tested and analyzed. The results showed that, the generator could output ultrasonic signals within a range of 15-50 kHz under the open-loop fixed function and could stably drive GMT to work at the working frequency for a long duration under the closed-loop frequency tracking function. Besides, this investigation also upgraded ultrasonic generator for GMT, and it was verified that upgraded generator could output more than 1 kW power by experiments.