Bi-directional Power Transfer of a Contactless Electric Vehicle Charger Using Direct Three-Phase to Single-Phase AC/AC Converter

This paper explains a bi-directional power transfer operation of an inductive charger using a direct three-phase to single-phase AC/AC converter. The converter has a fewer switches than a matrix converter with the same functionality and uses a resonant circuit to utilize zero-current switching. The charger is designed to charge electric vehicle battery, and the transfer operation will be applied to support power grid through a vehicle-to-grid application. The paper focuses on power transfer analysis of a series-series inductive power system with a switching frequency generated from a resonant current. Equivalent circuit and steady-state equations were developed to predict system behavior. Analytical calculations were compared with simulation outcomes for validation purposes. The analysis shows that the coupled system has three resonant frequencies, and power transfer capacity is affected by circuit coupling factor and battery voltage level.