Y-Configuration Active Bridge (YAB) Converter: A DAB-Type Single-Stage Isolated Three-Phase AC-DC Converter with Simple Sinusoidal Control

Abstract

This paper reviews commonly used three-phase isolated AC-DC converters and introduces a novel Y-configuration Active Bridge (YAB) converter for single-stage isolated AC-DC power conversion. The proposed YAB addresses the limitations of multi-stage designs by eliminating bulky electrolytic capacitor banks and input boost inductors, thereby enabling a simplified start-up process without the risk of inrush current. It retains the advantages of single-stage AC-DC Dual Active Bridge (AC-DC DAB) converters while significantly reducing control complexity. Across its entire operating range, the YAB achieves low total harmonic distortion, maintains relatively low current stress, and exhibits excellent soft-switching performance. The operating principle of the proposed converter is detailed, and an equivalent circuit model is presented. System performance is evaluated using a numerical Fast Fourier Transform (FFT) model. To validate the performance of the proposed converter, a three-phase 6 kW, 480 V YAB prototype is designed and tested in the laboratory. Experimental results demonstrate a maximum efficiency of 97.1\%.