Design of a position-independent end-to-end inductive WPT link for industrial dynamic systems

This paper will present the design of a position-independent inductive wireless power transfer (WPT) system for dynamic applications, where power is required to be delivered to a moving object on a path, such as industrial sliders and mass movers. A key feature of the designed inductive WPT system is to inherently maintain a constant dc output voltage, dc output power and dc-to-dc efficiency of the overall system, regardless of the vehicle's position. The system consists of an array of transmitting coils, where each coil is driven by a 6.78 MHz constant amplitude current generated from a load-independent Class EF inverter. The receiving coil is series tuned and is connected to a Class EF2 rectifier, which is numerically optimised to maintain a constant dc output, independently of the dc load. The system is powered from a 70V dc voltage source. GaN FET and SiC diodes are used to implement the Class EF inverter and rectifier. Results show a peak dc-dc efficiency of 83% at 150W with a 4% variation of the output voltage. The prototype of the complete link is under way.