Increasing the number of voltage levels in single-phase multilevel converters

The main focus of this paper is on the modification of single-phase Neutral Point Clamped (NPC), Flying Capacitor (FC) and Modular Multilevel Converter (MMC) structures. These converters can output a maximum voltage of V_DC/2 while they have a DC link voltage of V_DC. Hence, the structure of these three converters is modified to increase the number of voltage levels and the utilization of DC link voltage. Moreover, using this idea, the number of clamping diodes in NPC, flying capacitors in FC, and half-bridge cells in MMC can be reduced for generating the same number of voltage levels. Increased switching state redundancy and lower power loss are the main benefits of the proposed approach. Finally, MMC and NPC converters and their modified structures are simulated in Matlab/Simulink environment and their performances under different conditions are investigated.