Input DC Voltages of Three-level Neutral Point Clamped Voltage Source Inverter Balancing Using a New Kind of Clamping Bridge

Abstract

A serious constraint in multilevel inverters is the capacitor voltage-balancing problem. The unbalance of the different DC voltage sources of the three-level Neutral Point Clamping Voltage Source Inverter (NPC-VSI) constituted the major limitation for the use of this power converter. To remedy to this problem, a new control solution to compensate the unbalanced DC voltages for the three-level NPC VSI is presented. It provides a fast and flexible control of the inverter capacitor voltages, leads to a simpler implementation, and present high equalization efficiency. Simulation results show the effectiveness of our methods.