Non-Isolated Cascaded Multilevel Converter Based on Three-Phase Cells

This work proposes a new non-isolated cascaded multilevel converter topology based on three-phase cells, presenting lower construction and implementation cost than the classic multilevel converters topologies. However, this topology presents several short-circuit states when used with classic PWM switching strategies, which can make this structure unfeasible and cause damage to its components. To solve this technical challenge inherent in the proposed structure, an algorithm based on graph theory was developed in order to identify all converter possible states, including the short circuit states. A STATCOM simulation results are presented in the Simulink MATLAB software using the proposed topology based on instantaneous power theory, where an Optimal Switching Vector Model Predictive Control (OSV-MPC) was applied in order to use only the safe switching states, and prove its viability.