Real-time coupling coefficient estimation and maximum efficiency control on dynamic wireless power transfer using secondary DC-DC converter

Transmitting efficiency is able to be controlled by changing the input impedance on the receiving side using a DC-DC converter for static wireless power transfer system. However, the control method has never been applied for dynamic wireless power transfer system where coupling coefficient changes drastically. The information of coupling coefficient is needed constantly to achieve the control. Moreover, the considerations about dynamics of the transmitting circuit and coupling coefficient are necessary in dynamic wireless power transfer system. In this paper, a simple method of coupling coefficient estimation with RLS (Recursive least squares) filter and maximum efficiency control using a PID feedback controller are proposed. The simulation and experimental results of dynamic maximum efficiency control are provided and indicating the effectiveness of the proposed control in a real dynamic wireless power transfer system for EVs.