부산대학교 도서관

This paper presents an equivalent circuit for a non-tight transformer of a series-parallel-type resonant wireless power transfer system. The proposed non-tight transformer circuit is designed as an equation of state with a coupling coefficient parameter and it enables to consider its fluctuation while performing a simulation. In addition, we present a wireless power transfer system with a dual active bridge DC–DC converter. The proposed system synchronises by a phase-locked loop control system and transmits power. In order to confirm performances of the proposed system, we simulated a simulation of the system transfers power using a variable coupling coefficient and a simulation of the system transfers power bi-directionally. In addition, the proposed system adopted pulse width control can improve distortions of AC voltage and current when the dual active bridge DC–DC converter of the proposed system is supplied with different DC voltage sources. From the simulations, we confirm good results and proposed the wireless power transfer with a dual active bridge DC–DC converter that realizes high efficiency power transmission.