Multi-receiver and repeater wireless power transfer via magnetic resonance coupling — Impedance matching and power division utilizing impedance inverter

Future applications of wireless power transfer will include powering various devices in a room, charging electric vehicles in a parking area, charging moving robots and so on. Therefore practical wireless power transfer must be able to support complicated configurations for example combination of multi-receiver and repeaters. Many past works have discussed on methods for improving efficiency and more recently extended the methods to multi-receiver system. However controllable power division among receivers is also an important feature as receivers nearer to the transmitter tend to absorb more power compared to further antennas. In this paper, a new impedance matching and power division method utilizing impedance inverters only at receiver sides is proposed. The mathematical equations in the proposed method are then generalized for arbitrary number of receivers and arbitrary number of repeaters.