Structure Analysis of Magnetic Coupling Resonant for Wireless Power Transmission System

Using magnetically coupled resonators coils in a strongly coupled near field was suggested for wireless power transfer. A circuit model is presented along with a derivation of key system concepts such as frequency splitting, the maximum operating distance (critical coupling). Here, a simple circuit topological structure, the series-shunt-mixed resonant coupling, is presented with better performance in the transfer distance and efficiency. The theoretical analysis and experimental verifications of several resonant coupling structures have been investigated by several groups. In the experimental verification, a pair of resonant coils with 15 cm diameter was used. The experimental results show that high efficiency of 85% was achieved at a distance of 10 cm and 45% efficiency at 20 cm. Through the developed model, it is seen that the system can transfer power over a midrange of a few meters and that impedance matching is important to achieve high efficiency.