A capacitive power and signal transfer system based on ring-coupler with mitigated inter-channel crosstalk

Wireless power and signal transfer systems are becoming increasingly important in rotary applications due to their ability to charge and communicate rotating devices without physical contact. Capacitive coupler is one of the preferred solutions to achieve the above functions because of its advantages of size and weight. However, there are currently no suitable decoupled capacitive coupler design for CPT systems to mitigate the crosstalk between the power and signal transfer channels. This paper proposes a capacitive power and signal transfer (CPST) system based on ring-coupler with extremely weak cross-coupling. A comprehensive model for the dual-input and dual-output capacitive coupler is established, and the decoupling characteristics of the two channels of the proposed coupler are demonstrated based on this model. Then, analysis of both the power and signal channels was conducted, and design methodologies for both two channels were presented. Finally, the proposed decoupled coupler is experimentally verified and applied in the proposed CPST system. The results demonstrate that the proposed system can efficiently transmit 100W of power with an efficiency of \(84.5\%\). Additionally, it is capable of transmitting signals using Amplitude Shift Keying (ASK) modulation at a rate of 4800 bit/s, with an error rate lower than \(0.1\%\).