New Control Method For Dual Voltage Rectifier

Abstract

In this paper, a novel AC-DC converter having dual stage voltage rectifiers and voltage summation architecture is designed. Voltages of the two DC-buses are added together at the output port via down-stream DC-DC transformers (DCXs). The DC output voltage is controlled by regulating the voltage of the adjustable DC-busses of the DV-rectifiers. Therefore, voltage regulation is not required for the DCXs, which can always operate at their highest operation point to guarantee maximum efficiency. As the voltage of the adjustable DC-buses are changeable, multilevel voltages can be obtained with the DVrectifier, which is benefit for reduction of switching losses and improvement of conversion efficiency. To achieve current regulation of AC input port and voltage regulation of the two DC-buses simultaneously, multi-mode operation and smooth mode transition strategies are proposed for the DV-rectifier. Operation principles, control strategies and characteristics of the DV-rectifier and DCX-based AC-DC converter are analyzed in detail. Feasibility and effectiveness of the proposed solutions are verified with experimental results.