Analysis and Optimization of Wireless Power and Information Dual Transfer in Multicoil System

In magnetically coupled resonant (MCR) wireless power transfer (WPT) systems, intermediate coils are used to extend power transfer distance. The complex magnetic coupling among multiple coils poses a challenge for simultaneous wireless power and data transfer. Wireless power and information dual transfer (WPIDT) is recently proposed to modulate the transmitting data on one dc side and receives it on the other dc side. In this paper, the design and optimization of WPIDT systems with any number of intermediate coils is investigated. First, a general reduced-order model of the multi-coil MCR channel is developed. The information transmission properties are analyzed in the model by scattering parameters. Accordingly, the matching circuits for communication are studied to optimize for higher transfer gain. The transfer gain can be simultaneously optimized for both upward and downward communication in a symmetrical coil arrangement. Finally, a 27.7-W five-coil WPIDT prototype system is developed and tested to validate the theoretical analysis. The experiments achieve bidirectional data transfer at 20kbps.