Load-Isolation Wireless Power Transfer With K-Inverter for Multiple-Receiver Applications

Disturbances among the receivers caused by irrelevant circuit topology and inductive cross couplings among the receiving coils are particularly problematic aspects of multi-receiver wireless power transfer (WPT) systems. This paper proposes an effective and convenient scheme in which a K-inverter is inserted between an approximately 0 Ω output impedance voltage source and a transmitting resonator in order to isolate the receivers from each other, where the voltage and power distributed to each load are independent of other loads. The load-isolation principle is illustrated in detail. The indirect cross coupling aggravating the cross interferences is also investigated, and some practical criterions are derived to eliminate them. A three-receiver WPT experimental platform was established and tested to verify the theory; measured results were in close agreement with the theoretical values.