A fast and flexible nearest-level-equivalent space vector modulation algorithm for three-phase multilevel converters.

• Merely one nearest space vector closet to the origin requires to be detected online. • Redundant and optimized switching sequences are flexibly generated to achieve the minimum number of switching transitions. • Continuous modulation and discontinuous modulation modes are easily obtained. • It is more hardware efficient, independent of the level number and suitable for various multilevel converters. This paper presents a nearest-level-equivalent space vector modulation (SVM) algorithm for three-phase multilevel converters. The proposed algorithm provides a simple approach to obtain three modulation vectors online based on basic vectors. In addition, the principle of nearest-level modulation (NLM) is applied in the proposed SVM to make its superior performance to the generalized SVM algorithms, which present: (1) Merely one modulation vertex need to be detected and three-phase duty cycles are obtained. Therefore, the unbalanced voltages of inner cell of neutral-point-clamped cascaded multilevel converter (NPC-CMC) can be addressed; (2) Redundant and optimized switching sequences are automatically generated to minimize the number of switching transition; (3) Different modulation modes can be flexibly chosen to optimize the harmonic benefit. The proposed SVM scheme is independent of level numbers and finally verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]