Initial Current Injection Method of a Direct Three-Phase to Single-Phase AC/AC Converter for Inductive Charger

This paper explains an initial current injection method of a direct three-phase to single-phase AC/AC converter for an inductive charger. The converter has a lesser number of switches than a matrix converter and uses a resonant circuit to utilize zero-current switching. The method applies a DC resonant charging to charge a primary resonant capacitor, by taking advantage of the converter topology. The charged voltage is used to boost the initial current since in practice an affordable current transducer has only a limited measurement range, due to its accuracy and noise characteristics. The method is applied to kick-start the inductive charger without adding an amplification circuit to the current transducer output. Simulation results are presented to verify theoretical calculations.