*WINNER* Layered DD Coil: An Improved Coil Structure For Wireless Power Transfer

Abstract

Wireless power transfer is gaining application in electric vehicles and in the charging of biomedical implants. Inductance is a primary property that enables wireless power in an inductive wireless power transfer (IWPT) system. It indicates both the power storing and sharing capability of the coil involved.
The Double Dee (DD) coil is a coil type that has shown a significant amount of inductance for this purpose. To increase the DD coil inductance, more turns and a much wider area are required. With an area constraint, this will limit the use of the DD coil. In this research, a Layered DD coil is presented to further enhance the inductance capability of the DD coil and overcoming the area constraint. Multiple layers of the coil are used and the coils are oriented such that the emanating magnetic field adds up constructively thereby enhancing the coil inductance. Simulation and experimental implementation of the coil have shown an enhanced and superior performance in comparison to the parent DD coil. The use of shielding materials will enhance its overall performance and prevent or reduce the potential hazard of the field. Various shielding materials known to have good magnetic properties were investigated to determine their effect on IWPT. Ferrite, Cobalt-Iron, Steel were among the materials used and which showed significant prospects in IWPT. It was deduced based on their performance that cobalt-iron would enable a higher amount of power to be transmitted than ferrite. Other configurations of the LDD coil show the potential for cost-saving.