High Q Values Non-Uniform PCB Coil for Inductive Power Transfer

Inductive Power Transfer (IPT) garners significant interest owing to its wireless energy transmission capability. Its transfer efficiency directly correlates with quality factor (Q)values of transceiver coils, and therefore, reducing losses while preserving the self-inductance is vital. As the operating frequency rises to the megahertz (MHz) band, traditional stranded coil is difficult to maintain good performance due to the processing. Rising alternating current (AC) losses makes IPT system turns to PCB coil. However, printed circuit board (PCB) coil's AC losses dominated by proximity effects. To increase the Q values of the PCB coil, this paper proposes a novel coil with non-uniform wire spacing and wire width. Non-uniform wire layout strategy reduces the magnetic induction intensity (B) above the copper traces, thus reducing the eddy current losses. Also wire widths are designed to balance eddy current and conduction losses, resulting in overall losses reduction. Simulations demonstrate 7% AC losses decrease over conventional coils, with a Q value of 464.5, underlining its performance superiority.