Ferrite Core Optimization of Spiral Planar DD Coil for Efficient Wireless Power Transfer Applications

While wireless power transfer (WPT) has been commercialized in many designs, its application in electric vehicles (EVs) remains limited due to the challenges posed by power transmission efficiency. The coil structure and its core configuration, including shielding, play a crucial role in improving power efficiency. Although the Spiral Planar DD-Coil has demonstrated high efficiency, modifications can still enhance the WPT performance. This paper optimizes DD-Coil parameters and proposes an optimized ferrite core structure to minimize weight while maintaining low power losses. Our results indicate that the new core structure not only provides better efficiency compared to the shaped-bar core but also performs comparably to the traditional rectangular core. Additionally, our findings show that increasing the initial radius of the coil enhances power efficiency, while highlighting the trade-off between core thickness and core power loss.