Maximum Efficiency Operation in Wider Output Power Range of Wireless In-Wheel Motor with Wheel-Side Supercapacitor

Wireless power transfer (WPT) via magnetic resonant coupling has been widely studied for many applications. In the control of WPT systems with variable power load such as motor, achieving high efficiency and desired power corresponding to the load at any time is important. Some methods which increases efficiency by secondary side power converters has been proposed. In these research, however margin between possible transmission power which is determined by the primary and secondary side voltage and received power is necessary because WPT systems with variable power load is unstable. This paper proposes a method for maximum efficiency operation by dynamic voltage control of the primary and secondary side DC-link. Margin in the transmission power is unnecessary in the system configuration which has supercapacitor and DC/DC converter on the secondary-side because supercapacitor compensates power fluctuation. Simulations and experiments demonstrated feasibility of the proposed method and effectiveness of the controllers.