Wireless Power and Data Transfer in Industrial Nutrunners

Abstract: Wireless power and data transfer systems are experiencing an ever-growing consumer and industrial adoption. Its use in common devices has made the technology more accessible to people, but seldomly does it replace a physical connection inside a product. When two parts of an assembly are to be electrically connected, the solution has traditionally been connectors or wires. However, typical connection methods using physical connectors between two devices can be fragile and sensitive to dust and debris. In this degree project, a wireless power and data connection between two parts of an industrial nutrunner are evaluated. A very compact nutrunner encasement calls for a minimal wireless interface with high efficiency. Additional complications are met when the nutrunner body is made of metal, which introduces losses. Electromagnetic simulations of a flexible PCB transformer with ferrite film backing are performed in the simulation software Finite Element Method Magnetics (FEMM), and electrical performance is evaluated in the circuit simulator LT-Spice. From the best performing solution, a physical model is constructed and evaluated. The final implementation uses a flyback converter for power transfer, and amplitude modulated data for bi-directional data transfer. Results indicate the potential for excellent performance with 1 W power transfer with more than 50 % efficiency whilst simultaneously transferring data at a rate greater than 1 Mbit/s.