This paper presents a novel space-vector modulation scheme that can be processed quickly by a digital-signal processor, in addition to achieving minimum switching frequencies in the devicesof the converter. The modulation algorithm takes advantage of symmetry in the space-vectordiagram to process all the calculations within the first sextant. An equivalent reference vector in this sextant is used for the calculation of duty cycles and the definition of optimal sequences of vectors. By simply interchanging the final states of the legs of the inverter of this equivalentvector generates the original reference vector in the corresponding sextant. The total number ofswitching steps in the final sequences is preserved; thus, optimal sequences of vectors need only be defined in the first sextant. This strategy is especially attractive for multilevel convertersin which the total number of vectors and sequences is very high. Furthermore, since multilevelconverters are usually applied to high-power systems, reducing the switching frequencies of thedevices is an important goal. Efficiency of the modulation algorithm is verified in the three-levelconverter by simulation and experiment