Evaluation of Asymmetrically Modulated DC/DC Converters With Different Transformer Configurations

For isolated three-phase DC/DC converters, different transformer winding configurations shape the phase current differently, which results in different efficiency and power density. In this paper, the impact of four different transformer winding configurations on the performance of a current-tripler-rectifier three-phase full-bridge (CTRTPFB) DC/DC converter with asymmetrical modulation control strategy is studied using the same comparison criteria for all operation scenarios. Depending on the duty cycle and output current, the CTRTPFB converter operates in three different modes, DMIN, DMED, and DMAX. Comparison reveals that the Y–Y and the Δ–Δ configurations have similar performance, so do the Y-Δ and the Δ-Y configurations. In the DMAX mode, the Y–Y and the Δ–Δ configurations perform better than the Y-Δ and the Δ-Y configurations. In the DMED mode, owing to the controllable characteristics, the Y-Y and the Δ-Δ configurations are the viable choices. In the DMIN mode, the Y-Δ and the Δ-Y configurations perform better than the Y–Y and the Δ–Δ configurations. This paper provides a guideline regarding how to select the most suitable configuration for a particular operation and how to determine the circuit parameters.