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Summary: In this paper, a novel method named as level vector pulse width modulation (LVPWM) is proposed for multilevel inverters. Similar to the conventional space vector pulse width modulation (SVPWM), the proposed method is a vector‐based method in the α–β frame. Unlike the SVPWM, the variables of each of the α and β axes are considered separately. Instead of space vectors, level vectors are considered for the synthesis of the reference vectors. There is no need to consider multiple switching states, vectors, and large lookup tables in the algorithm. The appropriate switching states for the synthesis of the reference vectors are determined using simple computations at each sampling time. Generality for different inverter topologies, online implementation, simplicity of the algorithm and computations, independency of the algorithm complexity from the number of switching states, and easy extension to overmodulation region are the advantages of the proposed method. Implementation of the LVPWM in different inverter topologies is studied. The validation of the proposed modulation strategy is carried out by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Multilevel inverters (MLIs) with reduced number of switching devices and dc sources have compact size, reduced cost, and higher efficiency. This article proposes a transformer-based single-source MLI with reduced number of components and small size transformers. The proposed topology is a hybrid three-phase MLI assembled by a conventional three-phase two-level inverter (TTI) and two single-phase cascaded H-bridge inverters (CHBIs). The proposed MLI has a low ratio of number of active switches to number of output voltage levels. In order to use only one dc source, the CHBIs are cascaded with the TTI through transformers. An individual nearest level modulation (NLM) has been developed to control voltage of this inverter. Moreover, power distribution between its modules is analyzed. The total power of the transformers is 28% of the inverter rated power. Simulation and experimental results of a 13-kVA prototype verify the efficiency of the proposed arrangement. [ABSTRACT FROM AUTHOR]

Summary: This paper presents cascaded topology of three‐phase neutral‐point‐clamped converters (NPCC)s. Two or more NPCCs are cascaded in their AC sides through transformers. This multilevel inverter (MLI) is a transformer‐based single‐source inverter with trinary asymmetry. Compared with conventional and advanced diode‐clamped multilevel inverters, the proposed MLI achieves more levels on output voltage. From cost, number of components, volume, complexity and efficiency aspects, the proposed inverter is an optimized and advanced inverter. An individual space vector modulation (SVM) method has been developed for voltage control of the inverter. The neutral‐point voltage of the inverter is balanced conveniently by the SVM method. The proposed inverter is suitable for constant‐frequency applications. Simulation and experimental results of a 17‐kVA prototype verify the efficiency of the proposed arrangement. [ABSTRACT FROM AUTHOR]