Equivalence of SVM and Carrier-based PWM in Three Phase/Wire/Level Vienna Rectifier for Unbalanced Load

In this paper, the analysis of Space Vector Modulation (SVM) of a three phase/wire/level Vienna rectifier is conducted, according to which the implementation of the equivalent carrier-based PWM is deduced theoretically within each separated sector in the diagram of vectors. Compared with conventional three-level converters, the SVM of Vienna rectifier is different because of its operation principle, which is discussed in detail in this paper. In addition, the ability of the Vienna rectifier to work under unbalanced power grid is demonstrated as well. An adaptive and robust controller to balance the output voltage under the unbalanced load for different modulation indices is further developed. An experimental prototype of 2.5 kW Vienna rectifier was built to verify the validity of the theoretical analysis.