A Space Vector PWM scheme for a Single-stage Ac-Dc Modular Cascaded Multilevel Converter

Multilevel power converters have been intensively studied in the power electronics field. However, approaches involving the evaluations and proposals of novel modulation techniques, topologies and applications of semiconductor technologies keep this path as an open research area. This paper proposes a Space Vector Pulse-Width Modulation (SVPWM) approach applied to a Single-stage Ac-Dc Modular Cascaded Multilevel Converter (SMCM). The analysis of the switching vectors is performed in order to design optimal sequences for the improvement of key characteristics, such as multilevel voltage Total Harmonic Distortion (THD), input current THD, magnetizing current level, as well as efficiency. A modulation algorithm is proposed through a step-by-step code and a proper vector sequence from all possible switching states is shown. Simulation results validate the proposed modulation algorithm and its operation, with significant advantages over the classical Phase-Shifted Pulse-Width Modulation (PSPWM) technique.