A Five-Level Step-Up Module for Multilevel Inverters: Topology, Modulation Strategy, and Implementation

This paper proposes a new single-phase five-level converter based on the switched-capacitor technique. The capacitor charging in the proposed converter is carried out in a self-balancing form which does not need closed-loop modulations or additional balancing circuits. The proposed topology is a voltage booster without using end-side H-bridge for changing load voltage polarity. So, switching losses and total voltage stress of semiconductor components reduce in the proposed converter. The performing modes of the proposed topology, its modulation scheme, capacitors' balancing analysis, capacitance and loss calculations, and also the development of the proposed converter for enhancing the quality of output voltage waveform are discussed in depth. Moreover, the comparison of the proposed structure with the other multilevel topologies shows that the proposed converter can reduce the number of semiconductor elements and the required isolated dc sources. Finally, the simulation and experimental results validate the appropriate performance of the proposed converter.