A single-stage three-phase AC/DC converter with Y-Δ three-phase transformer

Abstract

400V DC power supply architecture for data center has been demonstrated to possess superior efficiency, power density and reliability compared with traditional ac architecture. A three-phase AC/DC converter is needed as the front rectifier to convert three-phase 380V AC voltage to 400V DC voltage. To achieve buck-boost AC/DC conversion and electrical isolation as well, this paper proposes a single-stage three-phase AC/DC converter with Y-Δ three-phase transformer. It achieves unity power factor, high-frequency electrical isolation, and adjustable output voltage with single-stage structure. To guarantee the voltage-second balance of three-phase transformer, the modified SVPWM algorithm is proposed. The operation principles and SVPWM algorithm are presented specifically. To verify the theoretical analysis, a 3kW prototype based on the proposed converter and SVPWM algorithm was built in the lab. And the experimental results show the good characteristics of the converter well.