Transfer efficiency control using switching devices in resonant magnetic coupling

The resonant magnetic coupling (RMC) method has advantageous features for mid-range wireless power charging. However, if a receiver is moved closer to a transceiver as transmission output remains fixed, excessive power is supplied to a load, which may cause considerable damage to the receiving device. In this paper, we propose a new efficiency control technique using nonlinear devices. Two switches with diodes are connected to the resonant capacitance in parallel and are turned on/off alternately at the transmission frequency. With this technique, receiving power control can be achieved without any communication between the transceiver and the receiver.