Suppressing Voltage Fluctuations With Optimized Assisted Coils in Dynamic Wireless Power Transfer

Dynamic Wireless Power Transfer (DWPT) is a promising technology for alleviating range anxiety and reducing the size, cost, and volume of electric vehicle batteries. However, DWPT systems often experience voltage fluctuations due to variations in mutual coupling caused by vehicle movement. This paper proposes the use of small auxiliary coils, referred to as ’assisted coils,’ placed between adjacent transmitter coils to mitigate voltage fluctuations. These coils are significantly smaller than the main transmitter coils, resulting in minimal cross-coupling between the assisted and main coils. Despite this, the mutual coupling between the assisted coils and the receiver coil is too small to fully compensate for voltage drops during transitions between main transmitter coils. To address this, the paper introduces a design strategy to define the ratio between the LCC compensation inductors of the main and assisted coils, ensuring stable voltage during transitions. The dimensions of the assisted coils are optimized using ANSYS Maxwell, focusing on minimizing voltage fluctuations and reducing cross-coupling. Simulation and experimental results validate the proposed approach, showing a stable voltage with a 55.06% improvement in output voltage during transitions between adjacent main transmitter coils.