Synchronous Rectification-Based Phase Shift Keying Communication for Wireless Power Transfer Systems

The receiver-to-transmitter communication in a wireless power transfer (WPT) system plays an important role in the closed-loop control. Existing methods for the communication use separate modules or additional power components connected with the resonant tank or load. Therefore, these methods suffer from low reliabilities, high costs, or large disturbances on power transfer. To overcome these disadvantages, this paper proposes a synchronous rectification-based phase shift keying method for WPT systems. The method is to modulate the phase difference between the rectifier input voltage and the receiver resonant current and demodulate the reflected phase difference between the inverter output voltage and the transmitter resonant current. The disturbance on power transfer caused by the modulation is numerically analyzed. Two encoding schemes, namely the binary encoding and the pulse frequency/width encoding are suggested for digital and analog data transfer, respectively. The maximum data rate, the highest pulse frequency, and the narrowest pulse width are derived based on the system dynamical characteristics. Experimental results are given to verify the method and analysis.