Dynamic period switching of PRS-PWM with run-length limiting technique for spurious and ripple reduction in fast response wireless power transmission

In this paper, we propose a control method in a wireless power transmission that targets small battery-less devices. Dynamic period switching of PRS-PWM (Pseudo Random Sequence - Pulse Width Modulation) with run length limiting technique has been developed to break through the tradeoff between transient response speed, rectified voltage ripple, and spurious emission. Developed wireless power transmission system has achieved ripple reduction by 44%, response speed of 70μs, and spurious reduction by 15.6dB.