Design And Research Of Contactless Power Transfer System For Rotary Ultrasonic Machining

The new hard and brittle materials represented by carbon fiber composites have a wide application prospect in the field of high-end science and technology due to their excellent physical and chemical properties,but also bring difficulties to the machining.As a special machining method,rotary ultrasonic machining has the advantages of small cutting force,low cutting heat and good surface quality of machined materials.It has unique advantages in the field of hard and brittle materials machining.Unlike traditional machine grinding,ultrasonic tools are integrated with transducers,which need to be fed with high-frequency alternating current.In recent years,the contactless power transfer with loosely coupled transformer as the core has gradually replaced the traditional brush and conductive slip ring contact power transfer.This paper focuses on the contactless power transfer technology applied to rotary ultrasonic machining,and the main research work is as follows:(1)The influence of different core angles on transfer performance of single emission loosely coupled transformer is explored.The structural parameters of the single emission loosely coupled transformer are designed,and the mutual inductance model of the single emission loosely coupled transformer is established.The influences of the primary and secondary coil resistance and coil mutual inductance on the transfer efficiency and output power of the power transfer system are analyzed,and the influences of changing the magnetic core angle on the transfer performance is further explored.By selecting the appropriate magnetic core angle,the system can greatly improve the output power while maintaining a high transfer efficiency to meet the needs of machining.(2)Propose a multiple emission loosely coupled transformer with high misalignment tolerance and a single capacitance compensation method.Firstly,the misalignment tolerance of the single emission loosely coupled transformer are analyzed,and then propose multiple emission loosely coupled transformer.The mutual inductance model of the multi-emission contactless power transfer system is established,and the misalignment tolerance of transfer efficiency and the output power under single capacitance compensation and multi-capacitance compensation are analyzed.The misalignment tolerance of three different combinations of systems was compared by experiments.Finally,the multi-emission rotary ultrasonic machining equipment was designed for rotary ultrasonic machining,which improved the misalignment tolerance of contactless power transfer system.(3)Propose a parameter optimization method of contactless power transfer system suitable for multiple transducers based on NSGA-Ⅱ algorithm.Aiming at the problem that a set of contactless power transfer system cannot be adapted to multiple transducers,a system optimization method based on NSGA-Ⅱ algorithm is proposed to optimize the number of turns of the primary and secondary coil and the compensation capacitance,so as to realize the adaptation of the system to multiple transducers.Finally,combined with the simulation experiment,the average transfer efficiency and output power of the system before optimization and the optimized system based on NSGA-Ⅱ algorithm are compared,and the effectiveness of the method is verified.