Design and implementation of three-phase resonant DC-DC power converter for low-voltage high-current applications

Abstract

The most commonly employed DC power supply in industrial processes, such as chemical electrolysis, aluminum potlines, DC arc furnaces, graphitizing furnaces, copper refining, plasma torches, the starting process of aircraft, the large Hadron collider, and nuclear fusion, is a magnetic confinement approach based on a line frequency isolated transformer with a phase-controlled rectifier. These power supplies suffer from high conduction losses, low efficiency, large size, and heavy weight. In this article, a high-frequency isolated three-phase resonant DC-DC converter is proposed for high power applications that demand low voltage, isolation, good regulation against load and line disturbances, and fast dynamic response. The modeling, control, and design of the proposed converter are carried out under symmetrical control with fixed frequency operation, and its steady-state analysis has been presented according to the description of the operational stages of the converter. Mathematical modeling of the LLC resonant tank network is presented, and its design curves are plotted against a variation of normalized frequency for different values of load. Based on mathematical analysis, a 5-V/150-A prototype model has been built and tested under various operating conditions, and the obtained experimental results are presented. © 2014 Copyright © Taylor & Francis Group, LLC.