Capacitive Power Transfer System With Integrated Wide Bandwidth Communication

Abstract

This letter proposed a novel method for compensation network design used in Capacitive Power Transfer (CPT) systems to achieve simultaneous power and data delivery. The proposed method combines both ladder filter and resonant circuit designs, allowing the existing double-sided CL compensation topology to exhibit different characteristics under the power channel and the communication channel. The proposed system significantly reduces the design complexity and increases the bandwidth for data transfer while maintaining the circuit resonance at the wireless power transfer frequency. The system is compatible with both Amplitude Shift Keying (ASK) and Frequency Shift Keying (FSK) modulation methods, passing the high frequency data carrier with an approximately unity gain. Detailed circuit parameter design and system performance analysis are presented, and a new metric Power to Signal (PSR) is introduced to analyze the effect of the data communication on the power transfer. A prototype CPT system rated at 10W is built, which demonstrates a 81.2% DC-AC efficiency and a data transfer rate of 10kbps by using either ASK or FSK modulation techniques.