Two-Stage Factorized Power Architecture DC–DC Converter for Spacecraft Secondary Power Supply System

Abstract

In this article, we propose a two-stage factorized power architecture (FPA) dc–dc converter, which caters to applications that require high efficiency, high power density, low ripple, and high dynamic response of space-borne low-voltage and high-current power supply. The first-stage 48 V intermediate bus converter (IBC) adopts the six-phase interleaving magnetic integration buck converter (IMIBC). A new array high symmetry multi-phase coupled inductor (CI) is constructed, and a general zero-voltage switching (ZVS) control strategy is proposed. The designed IBC provides 2.4 kW power with a density of up to 1400 W/in3 and efficiency up to 97.15%. The second-stage point of load converter (POLC) adopts the four-phase interleaving magnetic integration LLC dc/dc transformer (DCX). A new method of current sharing, which is based on the inverse coupling resonant inductor, is proposed. This method yields good current sharing under a 15% mismatch of resonance parameters. A highly symmetrical four-phase resonant CI and a four-phase magnetic integration transformer are developed; the design of magnetic components is optimized by constructing a high-precision magnetic circuit mode. The designed POLC has a power density of up to 700 W/in3 and an efficiency of up to 97.1%. Finally, the experimental prototype is fully tested against a similar type of Vicor’s products. According to the results, the power supply designed in this article has several benefits with regard to efficiency, power density, transient response speed, and ripple.