Five-Level H-Bridge NPC Converter Control with Minimum Commutation

In this paper, an Optimized Pulse Width Modulation (OPT-PWM) control for a Multilevel Converter (MC) is proposed. The control principle is based on the optimization of the number of commutations. The OPT-PWM control is applied on a five-level H-Bridge Neutral Point Clamped (HB-NPC) converter. First, all of the switching states for all voltage levels are examined. Then, to perform the commutation from a voltage level to another one, all of the possible trajectories from the initial state to the final one are considered. The best of them is chosen, according to minimum number of commutations criteria. A state machine is used to realize the proposed control method. Finally, the OPT-PWM control is verified on a five-level HB-NPC and validated by simulation results.