A Single-Phase Direct AC-AC Wireless Power Transfer System Using Conduction Mode-Exchanged Pulse Density Modulation

This paper presents a new prototype of a single-phase, direct ac-ac converter for inductive wireless power transfer (WPT) applications. The proposed WPT features a power control methodology based on pulse density modulation (PDM) suitable for a wide range of soft switching and fixed frequency operation, which is beneficial for switching loss minimization and circuit parameter design. The essential performances of the proposed system are investigated by an experiment of a 25-kHz small-scale prototype, whereby the direct ac-ac power conversion and PDM-based power control characteristics with wide-range soft switching are revealed.