Air Gap Design of in-Tire Repeater Coil for Dynamic Wireless Power Transfer System Considering Tire Deformation

Abstract

Wireless power transfer (WPT) to in-motion electric vehicles can extend the cruising range without additional batteries. Our group has already proposed a novel dynamic WPT system using in-tire and in-wheel repeater coil, which can shorten the air gap between the coils on the road and tire sides. In WPT system, the air gap should be as small as possible from the viewpoint of efficiency and leakage electromagnetic field. However, it is necessary to have a sufficient air gap to avoid coil damage by tire deformation. The maximum tire deformation when overcoming bumps of various heights at different vehicle speeds is experimentally measured with two different tires, normal tire and self supporting runflat (SSR) tire. The measured results show advantages of using SSR tire for the proposed WPT system.