Pre-charge Method Using a Bi-directional Isolated DC-DC Converter

Abstract

This paper proposes a capacitor pre-charge method using a bi-directional isolated DC-DC converter. This converter topology works as a phase-shifted full bridge DC-DC converter under forward direction of power conversion. In addition, this converter topology works as a current-fed converter under backward direction of power conversion and can operate in both the buck-mode and boost-mode. Then, a switching control method is presented for the voltage critical area of buck-boost. Appropriate input current control can be achieved by this switching control method in the voltage critical mode of buck-boost. Finally, the effectiveness of this pre-charge method is verified through an experiment on pre-charge using a 200V, 1000µF capacitor.