Maximum efficiency control of wireless power transfer via magnetic resonant coupling considering dynamics of DC-DC converter for moving electric vehicles

Wireless charging for moving electric vehicles could extend their cruising distance. Wireless power transfer via magnetic resonant coupling is suitable for this application. The transmitting efficiency can be maximized by using a DC-DC converter on the secondary side. The control system, however, must be designed properly to satisfy the response requirements depending on motion of the vehicle. Previous controllers were designed without considering the dynamics of the DC-DC converter for wireless power transfer via magnetic resonant coupling. This paper proposes the design method of secondary voltage control with a feedback controller using a novel DC-DC converter model based on the analysis of wireless power transfer system. Experiments show that the proposed model is effective and that the secondary voltage control improves not only the transmitting efficiency but also the charging power at any transmitting distance.