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

In this paper, the analysis of Space Vector Modulation (SVM) of 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. The voltage balancing ability of DC-link neutral point, which depends on the uneven distribution of short vectors, is analyzed as well. An adaptive and robust controller to balance the output voltage under the unbalanced load limit for different modulation index is proposed. Furthermore, the maximum of unbalanced load is deduced versus the modulation index m. An experimental prototype of 2.5kW was built to verify the effectiveness of the theoretical analysis. Finally, the tested unbalanced limit of outputs for the experimental platform was given under different modulation index.