Auxiliary Circuits for Power Flow Control in Multifrequency Wireless Power Transfer Systems With Multiple Receivers

This paper describes a technique for multifrequency wireless power transfer systems in which the wireless power can be transmitted through the wireless power transfer channel or channels from the transmitter to the targeted loads with receiver coils specifically tuned for energy reception. Auxiliary circuits comprising bandpass and/or bandstop circuits are proposed for incorporation into the receiver circuits and optional relay circuits so as to facilitate the selection and enhancement of the wireless power transfer to the designated load without causing significant cross interference due to the use of multifrequency wireless power flow control. A unique feature of this technique is that the nontargeted receiver will automatically act as a relay resonator to enhance 1) magnetic coupling, and thus, 2) the power transfer between the power transmitter and the targeted receiver. A second novel feature is that the chosen operating frequencies for the tuned receivers need not be widely apart because the auxiliary circuits consist of bandpass and/or bandstop filters to reduce any cross interference from the nontargeted frequency. The proposed technique has been practically verified in experimental prototype.