Efficiency Maximization of Inductive Power Transfer System by Impedance and Switching Frequency Control in Secondary-side Converter

Many of previous studies have focused on the efficiency of only one component of inductive power transfer (IPT) system, so the efficiency improvement of multiple components of the system has not been considered sufficiently. Therefore, this paper focuses on multiple components, which are the resonant circuit and the secondary-side converter, and proposes a control method to improve the efficiency of these components. As a result, the overall system efficiency is improved. To improve the multiple components’ efficiency, the load impedance control for resonant circuit and switching frequency control to the secondary-side converter were applied. As a result, the combined efficiency of the resonant circuit and the secondary-side converter was raised at the maximum of 1.2 points or 1.3 points with the proposed control where the resonant coil coupling factor was 0.3 or 0.2.