Simultaneous Wireless Power and Data Transmission Based on Unsymmetrical Current Waveforms With Duty Cycle Modulation

This paper proposes an active-clamped inverter (ACI) with duty cycle modulation for achieving simultaneous wireless power and data transmission (WPDT). The proposed method adjusts harmonic amplitudes by changing the duty cycle of the inverter, as a means to encode information alongside power using a shared wireless channel. This method generates a variable unsymmetrical current waveform corresponding with different duty cycles. By controlling the duty cycle, simultaneous power and data transfer can be achieved by using the fundamental and harmonic components respectively. The ACI is designed to operate in continuous current mode to reduce the variation of harmonic components, even under no load conditions. A simple ACI containing two switches is proposed to generate unsymmetrical current waveforms with a high efficiency and high circuit quality factor Q. Two communication methods are developed to balance the power transfer capability and signal-noise-ratio (SNR). Various separation distances and loads are tested, with experimental results showing the proposed system can achieve simultaneous power and data transfer across a shared channel in an inductive wireless power transfer.