Analysis and Design of Wireless Bidirectional Power and Data Transfer with Decoupled DD-R Coil Geometry

This paper proposes and implements a novel wireless bidirectional power and data transfer system using decoupled DD-R (Double-D and rectangular) coil geometry. Double-D power coils are placed in overlap with rectangular data coils, at both primary side and secondary side, respectively to form a compact structure. The slight power-data coupling under displacement and parasitic effect is neglected in previous decoupling structure studies, which may cause a significant decrease in SNR (signal-to-noise ratio), especially in high-power applications. A fully analytical design method of the data channel is proposed aiming to minimize the number of turns and maximize SNR considering parasitic parameters and displacements, which can give an optimal region quickly and is applicable to Double-D power coils of different sizes. The coupling characteristics of the power and data coils are first presented. Then the data channel performance is analyzed and the corresponding design objectives, limits, and principles are obtained. An optimal design method is further developed and a detailed design example is given based on the above analysis. Finally, a 5kW hardware prototype is constructed. The data transfer rate is 200kbps and the BER (Bit Error Rate) is 1.9e-5. The experimental results verified the feasibility of the proposed system and the validity of the design method.