A magnetically resonant coupling system for wireless power transmission

Magnetically resonant coupling is a steady and feasible approach for wireless power transmission (WPT), also called contactless power transfer. This paper presents a process to design a complete WPT system which can be connected to daily alternating current (AC) power source directly. Subsequently, by comparative simulation and experimental analysis between circular coil pair and octagonal coil pair on the printed circuit board (PCB) reaches the conclusion that the former has better performance in the WPT unit system. Each pair is measured by the vector network analyser (VNA) to acquire the values of serial resistance, mutual inductance and self inductance. These parameters can be set into Advanced Design System (ADS) to find the operating characteristics of the resonance circuit and the power efficiency of the coil pair system. With this simulation and experiment in PCB coil pairs, the complete WPT system including AC-direct current (DC) converter, primary driven circuit, PCB circular coil pair spaced 15 mm apart and secondary rectifier circuit is designed and tested. The whole system achieves a power transmission efficiency of approximate 50% at the frequency of 500 KHz.