A 6.78 MHz Full-Duplex Simultaneous Capacitive Power and Data Transfer System for Rotary Steerable Drilling Application

Wireless power transfer (WPT) technology could provide a safe and reliable power supply for rotary steerable drilling applications, but lightweight and communication are urgent requirements. Also, the drilling process is accompanied by vibration and medium changes. This paper proposed a full-duplex simultaneous capacitive power and data transfer (SCPDT) system with a shared channel to address these challenges. The operating frequency of 6.78MHz with a double T-type compensation topology makes the energy transfer of the system stable under the drastic increase in coupling capacitance. In addition, the notch filter and amplitude shift keying (ASK) method are adopted to achieve full-duplex communication. The gain of the communication channel is analyzed to solve the problem of full-duplex communication under variable coupling capacitance. An experimental prototype is built to validate the effectiveness of the proposed 6.78MHz SCPDT system. The communication rate of the system could reach 200-kbps, where the transfer power is 128W with 83% efficiency. The experimental result shows that the system's output can stabilize when the coupling capacitance increases sharply. Meanwhile, the output power of the energy transmission channel and the signal gain of the communication channel are almost unaffected by the change in the coupling parameters.