Effect of cutting tools and dynamic primary compensations on the working performance of contactless energy transfer system for rotary ultrasonic machining

In rotary ultrasonic machining, contactless energy transfer (CET) unit transmits electric energy from an ultrasonic power supply to a transducer, which converts the energy into ultrasonic vibration of the tool. Compensation enhances this transmission efficiency. However, the tool varies under different working conditions, changing the working performance of contactless energy transfer system (CETS), and fix compensation decreases CETS working performance under different tool parameters. To investigate the impact of tool size and dynamic compensations on CETS working performance, the equivalent-circuit models of CETS with dynamic primary compensations are developed, including dynamic primary series and parallel compensations, and examines the effect of tool on the transducer parameters. Subsequently, the effect of dynamic primary compensations and their variations on the CETS frequency characteristics, the influence of tool parameters and dynamic primary compensation variations on CETS transfer performance, and the sensitive analysis of CETS transfer performance on tool parameters and dynamic primary compensations are investigated. Finally, the experiment is conducted to validate the effects of tool and dynamic primary compensations, and the experimental results are consistent with the analysis above. Furthermore, the experiment also shows that a large tool extension can ensure the energy transmission of cutting tool, the dynamic primary series and parallel compensations are suitable options considering the stable output of ultrasonic power supply and load detection of transducer, respectively.