A high-power-density DC/DC converter for high-power distributed power systems

This paper presents a zero-voltage-switching (ZVS) three-level DC/DC resonant converter for high-power distributed power systems. The paper first addresses the operation of the converter at a fixed frequency, which is achieved by applying phase-shift control between the primary and the secondary sides of the transformer. Next, the operation of the converter at variable frequency is presented. In both operating modes, the converter can achieve ZVS operation in the entire load range by using the magnetizing inductance of the transformer. In addition, the converter can operate with wide input voltage variations without penalizing the efficiency. As a result, the converter is suitable for applications in which high efficiency and high power density are required. The principle of operation for the converter is analyzed and verified on a 2.75 kW, 745 kHz experimental prototype.