New State Vectors Selection Using Space Vector Modulation in Three Dimensional Control Regions for Multilevel Converters

A new and generalized three-dimensional space vector modulation algorithm for multilevel converters is presented. This new possibility is compared with an existing one concluding with the similitude and differences. Three-leg three wire, three-leg four wire and four-leg four wire multilevel converters are studied. This modulation technique uses the minimum number of tetrahedrons inside a cube, where each tetrahedron has four vertices which permit to generate a reference voltage vector. The proposed technique calculates the switching state vectors and the duty cycles without using angles, trigonometric functions or look-up tables. The low computational cost of the proposed method is always the same and it is independent of the number of levels of the converter. In general, the presented algorithm is useful in systems with or without neutral, unbalanced load, and harmonics generation