Three-phase single-stage three-level AC/DC converter with a wide output voltage control range

In this paper, a three-phase single-stage three-level AC/DC converter with a wide controllable output voltage is presented. The proposed converter integrates a PFC circuit and a three level DC/DC LLC circuit into one. Moreover, it operates at a fixed frequency and provides a wide controllable output voltage (200Vdc-430Vdc) with a high efficiency over a wide load range. In addition, the input boost inductors operate in a discontinuous mode to improve the input power factor. The switching devices achieve ZVS, and the converter's THD is small. The feasibility of the proposed converter is verified with experimental results of a 2kW prototype.