Low-cost efficiency tracking method for wireless charging system

Based on the three different process of battery charging, we proposed a design and optimization method for wireless charging system by introducing the duty cycle (D) information of the switching regulator in the receiver (Rx). D changes monotonically as it is dependent on the supply voltage (Vp) of the power amplifier in the transmitter. By feeding back power information, a power regulation circuit is proposed to automatically adjust the transmitting power, so the stability of the wireless power transfer is improved.