Design and Implementation of Interleaved Vienna Rectifier with Greater than 99% Efficiency
Three-phase rectifiers have been widely used in industries and increasing efficiency has always been a hot topic. Conventional 2-level 6-switch boost rectifiers are dominant due to their simplicity. However, in order to achieve a higher efficiency, 3-level converters are better options because lower switching voltage allows for the use of lower voltage switches, which usually presents lower on-resistance and smaller junction capacitors. Among the 3-level topologies, Vienna rectifiers are widely used to achieve high efficiency. With the use of a SiC diode, the reverse recovery loss from diodes in Vienna rectifiers can be totally eliminated, which further makes the Vienna rectifier a promising topology in achieving high efficiency. Additionally, unlike other bi-directional topologies, there is no need to worry about the shoot-through problem. Thus, in this paper, a Vienna rectifier is selected as the basic converter unit for the interleaved system.
Paralleling switches or converters are commonly used to achieve higher efficiency and better thermal management. In such practices, interleaving the gate signals of several sub-converters instead of simply gating them simultaneously can further enhance efficiency and power density. The cancellation effect among the interleaved sub-converters allows for smaller input filters. In other words, to achieve the same power quality with the same passive components, the switching frequency of each sub-converter in the interleaved systems can be lower, which lowers switching loss. Additionally, applying the interleaving technique may reduce EMI filter size due to its cancellation effect among sub-converters. Thus, the interleaved Vienna rectifier, which merges the advantages of the Vienna rectifier and interleaved systems in achieving high efficiency, is discussed.
In this paper, the design of a 3 kW, three-phase, two-channel interleaved Vienna rectifier with greater than 99% efficiency is presented. The converter efficiency is optimized for 230 V, 360~800 Hz input voltage, 650 V output voltage and 3 kW output power under a power quality requirement from a standard DO-160E. The operation principle of the interleaved Vienna rectifier is presented, with special attention given to circulating current generation and suppression. A comprehensive design procedure for the interleaved Vienna rectifier, including a design flow chart, loss estimation for the converter, design guideline of interphase inductors and semiconductor selection is described. A converter prototype is built and experiment results are shown, verifying the validity of the design procedure.