Wide-Range Adaptive IPT Using Dipole-Coils With a Reflector by Variable Switched Capacitance

A dipole-coil-based inductive power transfer (IPT) with a reflector, which first adopts the variable switched capacitance for load power regulation under very wide-range distance variation between transmitter (Tx) and receiver (Rx) coils, is newly proposed. The resonant frequency of the LC tank of the proposed IPT can be appropriately modulated by the variable switched capacitance with reliable zero-voltage-switching (ZVS) operations. Therefore, even though the distance changes very widely, load power can be regulated solely by the variable switched capacitance in the Rx circuit without complicated communication links between the Tx and Rx coils. A detailed static analysis based on a recent imaginary gyrator model and design procedure for the proposed IPT are presented to build a simplified LC resonant tank of the proposed IPT and ZVS condition and to identify applicable distance variation range for constant load power. A prototype of the Tx and Rx coils for 100 W of load power, considering average power consumptions of home appliances, was fabricated and verified by simulations and experiments, which showed that load power was completely regulated to 100 W for 23–70 cm of very wide-range distance variation at a fixed switching frequency of 140 kHz.